Short Notes in Plastic Surgery

June 19, 2019

6A. Vacuum Assisted Closure

Filed under: Chapter 6A — ravinthatte @ 5:06 am

6A. Vacuum Assisted Closure

(Also popularly called by its short form VAC)

Introduction

When this blog was begun in 2011, Vacuum Assisted Closure or VAC as an aid in improving the quality of wounds as well as their preparation for final closure with a suitable skin cover was just about making its presence felt in Indian hospitals. In fact, there was an official presentation on the technique in the annual meeting of the association of plastic surgeons of India in Goa where that meeting was held in the year 2010. Since then VAC has come to be accepted as a routine technique for preparation of wounds prior to their closure or cover by skin grafts or flaps. In fact, the technique is also used after a skin graft is applied and has shown good results in the “take” of the grafts because the suction that the VAC machine employs increases the force with which the graft comes to oppose the recipient area and an elaborate “tie over” dressing is not required to eliminate the possibility of the graft shearing away from the recipient area. In view of this background this small chapter is being added to the section on skin grafting for which Dr. Parag Sahasrabudhe the head of the department of plastic surgery at the Sassoon General Hospital in Pune, Maharashtra, India was invited to contribute. The compiler of these “Short Notes” thanks him and his colleague Dr. Amey Bindu for their efforts. The compiler of these short notes also thanks Dr. Sitaram Prasad and Dr. Shailesh Ranade of Mumbai India for providing suitable illustrations for this chapter.  

History

That wounds improve by being sucked was known in ancient times and Ayurvedic texts of ancient Indian medicine around and before the Christian era describe an appliance called GHATI YANTRA in the form of a cup (probably an earthen ware) which was heated prior to application around the wound and later had a sucking effect on the wound as it cooled and settled down to the ambient temperature.

During the Roman empire the wounds suffered by its soldiers were routinely sucked by mouth by other men and some of them were proficient enough in this art and were called to perform the act routinely. In the story of Cleopatra who was bitten by a poisonous snake (an Asp) such a professional “sucker” was supposed to have been commissioned but the treatment did not succeed and Cleopatra succumbed to the Asp’s bite.

In the eighteenth and nineteenth century cupping to improve wounds was quite common and one such cup was called the “leech cup” in England to indicate that the cup was doing the same thing that leeches did when they sucked the periphery of the wounds to reduce oedema. In fact, the deity associated with Ayurved (Dhanwantari) has a leech in one of its many hands.

The modern history of mechanical suction of wounds begins in Afghanistan in 1985 when Bagaoutidinov, a Russian surgeon used a mechanical suction machine to treat wounds suffered by Russian soldiers injured in the Russo- Afghan war.

However, the real beginning to the formal description and use of a suction machine with the help of polyurethane non-absorbent foam and tubes must be credited to Drs. Louis Argenta and Michael Morikwas from the Wake Forest School of Medicine in North Carolina, USA in 1990.  

Nomenclature and principles

The principle of the technique is to seal the periphery of the wound with a barrier then apply a sheet of poly urethane foam of the size of the wound and then cover it with a transparent film. A drainage tube is then placed over the foam through this film and the other end of the tube is attached to a suction cannister with a negative pressure between 80 and 125 mms of mercury. This system also goes by the name ‘negative pressure wound therapy (NPWT)’ Topical negative pressure (TNP) or Vacuum sealing technique

How does VAC work? Some rational presumptions

  1. The sub atmospheric pressure around the wound produces a mechanical stress leading to an inflammatory response and angiogenesis which helps create granulation tissue. Such mechanical stress is known to produce angiogenesis in another technique called tissue expansion.
  2. The outflow of interstitial tissue both from the wound bed and the surrounding tissue helps reduce edema and allows greater blood flow and scavenging activity.
  3. The drainage of the exudate reduces harmful proteolytic enzymes a product of bacterial inflammatory activity and also reduces the bacterial load
  4. It has been postulated that the deformation of moribund cells is a stimulus for regeneration of new cells together with deposition of protein and cellular matrix.
  5. With the bacterial load decreasing this generation of new cells reduces wound size
  6. In those cases where dryness is a problem, newer models of the VAC machines also employ a separate channel for irrigation with an antibacterial fluid to maintain a moist environment in and around the wound 

Clinical applications

The VAC assisted treatment for wounds and ulcers is most frequently used with great success in the following conditions:

  1. Immediately for a highly contaminated wound after debridement in which the zones of viable and non-viable tissues are not apparent.
  2. The same kind of wound seen after an interval where contamination has led to infection the wound has become fulminant or indolent and needs to be prepared for skin cover.
  3. Dep and intermediate thickness burn wounds of a limited size which have not had the benefit of early skin cover and are being readied for skin cover.
  4. Sternal dehiscence or burst abdomens following surgery to improve the wounds prior to a final formal closure.
  5. Sizable pressure sores after an initial debridement or even in between successive debridements.
  6. Ulcers on the inferior extremity of venous diabetic or indeterminate etiology prior to their closure by skin cover.
  7. VAC has also been tried for entero-cutaneous fistulae.
  8. Necrotizing fasciitis after the lesion is reasonably controlled with parenteral antibiotics and after decompression of a compartment syndrome if it was present.
  9. The system is also extremely useful when skin grafting is performed particularly on uneven surfaces and where a tie-over dressing is difficult to maintain. The meshed graft is covered by the urethane foam and the suction helps oppose the graft to the recipient bed by taking away any exudate which might form a film preventing neo vascularization of the skin graft.

Under what circumstances the VAC system does not work or must be used with caution

  1. The VAC system does not help when the wound is covered with a thick eschar or in cases of osteomyelitis. In both conditions either a thorough debridement and/or removal of sequestra and shaving away of dead infected bone as well as the eschar must precede the application because the system is meant for improving wounds not to remove dead adherent tissue or to treat the underlying disease The VAC system also will not benefit in the treatment of fistulae surrounded by ulcers.
  2. The system must be used with great caution if the bed of the wound is occupied by an organ which is bare or major nerves or vessels are exposed in the wound and is best avoided.
  3. It is contraindicated in patients on anti-coagulant therapy for fear of bleeding  and for malignant lesions because negative pressure will stimulate cell growth and cause the spread of the lesion

Newer Modalities

VERAFLOW Technique:

VAC VERAFLOW is a newer modality of NPWT therapy marketed by KCI, in which the device has an option of irrigation of the wound by a topical solution like plain saline or topical antibiotic or antiseptic solution, with simultaneous intermittent negative suction and removal of the fluid. The “soak-time”, suction pressure and negative pressure can be modified as per requirements.

This therapy helps in cleaning the wound with topical solution, local delivery of topical antimicrobial or antiseptic solution, and maintaining a moist environment to improve the healing. The irrigation used in the VERAFLOW technique helps clean the wound and can also achieve local delivery of an antiseptic or an antibacterial solution in addition to keeping the wound moist.

Complications

There are no major complications associated with VAC therapy. Skin irritation may be noted in few patients. There may be some pain while changing VAC dressing. In some situations, the cost of the therapy also proves to be an issue that needs to be considered.

­­Clinical Examples

Following pictures contributed by Drs. Parag Sahasrabuddhe and Amey Bindu, Pune, Maharashtra, India

Following pictures contributed by Dr. Shailesh Ranade, Mumbai, Maharashtra, India

Following pictures contributed by Dr. Sitaram Prasad, Mumbai, Maharashtra, India

Avulsion Rt. Arm with Chest wall defect

Degloving Injury of Chest wall

Extravasation

Perineal Degloving

Sacral Pressure Sore

May 16, 2019

63A. The Inverted Nipple of the Female Breast

Filed under: Chapter 63A — ravinthatte @ 4:35 am

This blog began almost ten years ago and was written in continuity. However the compiler of this blog has continued to attend scientific meetings in India and as and when a subject not yet covered in this blog came to his notice in these meetings those subjects are now included. In January 2019 at the meeting of the Maharashtra State Chapter of the national Association of India’s Plastic Surgeons, Shailesh Nisal of the Sparsha Clinic in Nagpur, India presented an excellent paper on the Inverted Nipple of the female breast and was invited to write on the subject. That chapter is reproduced below.

63A. The Inverted Nipple of the Female Breast

Prevalence

Several studies have shown that the incidence of congenital inverted nipples in unmarried females is about 3-4%. Of these 86% are bilateral while 14% are unilateral. 96% of these could be everted either by a cold touch, suckling or by eversion with fingers. These which can be everted do not need surgical intervention (except when cosmetic correction is desired) because the nipple comes out on suckling by the baby and normal feeding is possible.

Types or Grades

Grade I

  • Shy nipples
  • Easy protraction with gentle pressure  

Grade II

  • Brought out with difficulty
  • Retracts when released

Grade III

Cannot be brought out and in a vast majority of cases lactation is not possible in spite of a surgical correction This condition may hinder drainage of sweat or the normal discharge from the nipple leading to crusting soreness infection and a rash in the surrounding skin.

Grade III Inversion of the nipple, cannot be brought out and there is soreness and crusting in buried part. Lactating ducts likely to be cicatrized and the patient will not be able to lactate.

Nipple inversion can be Congenital/Pubertal or Acquired. When a normal projecting nipple in an adult female puckers or inverts over a period of time the cause is either an inflammation or a malignancy. This warrants serious evaluation and management based on the cause. The present discussion concerns itself purely with Congenital or Developmental (Nipple) Inversion of the nipple.

Indications for surgery

The indications for surgical intervention are both cosmetic as well as functional. Nipples that project from the areola are a part of the erotic appeal of a woman. In addition, the sensations that arise from nipples when handled are a part of the erotic experience that a female enjoys.

Grade II correction in Nulliparous women should be avoided since they may be able to lactate normally without intervention.

Grade III inverted nipples have severe cicatrisation of lactiferous ducts and usually such breasts fail to lactate successfully with or without surgery and this fact must be conveyed to the patient so as not arouse such an expectation.

Surgery

  1. Two cross stay sutures are taken to bring out the inverted nipple by traction.
 Cross sutures to evert and bring out the nipple
Small incision at 9’O clock position at the desired base of the nipple is sufficient to do the transection as well as the encircling suture which is described in the steps narrated below.

2. The incision measures a few mms (from) at the base of the nipple at 9’o clock for the right breast and at 3’o clock for the left breast assuming that the surgeon is standing on the right side of the patient as she lies on the table

A pair of scissors is passed in the subcutaneous plane all around while pulling and hooking out the bands which were tethering the nipple inward. All tight bands are cut one by one while continuing to apply traction on the stay sutures. The end point is reached when the nipple stays everted and projects itself without any pull on the traction sutures.

The release is complete once the nipple stands out in the desired position even after traction on the suture is eased.

T

The tight band pulling the nipple are hooked out and then transected one by one so as to cause eversion without traction.
When combined with excision of Fibroadenoma a peri-areolar incision may be used for the same procedure

3. An encircling purse string suture is taken through the subcutaneous tissue at the level of the desired base of the nipple. The knot is tied tight enough to not allow retraction but loose enough not to cause a vascular compromise.

 Encircling suture at base of nipple with absorbable suture, tight enough to prevent retraction but loose enough not to cause vascular compromise

4. The Incision is closed with absorbable suture such as 4-0 Vicryl or Monocryl for both the purse string as well as the closure of the skin.

5. Another purse string suture can be taken through the skin only if the bands were found to be very tight and the Surgeon fears a recurrence of inversion in spite of transection of all the bands and the previous suture in the subcutaneous plane. Here too care is taken in tying the knot as narrated in point 3.

Dressing

The Principle in dressing these wounds is not to have the slightest pressure on the newly everted nipple during the phase of healing and maturation.

There are 2 ways of doing it. First by placing an open lid upside down with 2 holes on its top through which the stay sutures come out and are tied so as to retain traction on the nipple. The vascularity of the nipple can be inspected through it if the lid is transparent or by gently lifting it and seeing underneath the lid without untying the knot. The other way is to place a thick foam with a hole in its centre in which the nipple sits in a relaxed fashion without any pressure on it. Such a foam is any case necessary inside the brassiere for 3 months till healing occurs. This is to prevent the pressure of the brassiere on the nipple causing the transected bands to reunite and result in recurrence.

Foam with a hole to avoid even slightest pressure on the operated nipple, this continues for 6 weeks till mature healing occurs.
Cross sutures passed through holes in a plastic lid and tied to maintain traction. The lid prevents any pressure of dressing or Bra on the everted nipple

The traction sutures are removed between the second and third week

Results

Satisfactory eversion maintained after 3 yrs.

If done carefully and with attention to detail the results are gratifying.

The possible complications are partial or complete necrosis of the nipple due to devascularisation and recurrence of inversion. Both would result from the way the purse string suture is applied. A tight suture can lead to de-devascularisation and a loose one may lead to a relapse.

April 20, 2019

Chapter 72.  Injuries Of The lower brachial Plexus C8 T1

Filed under: Chapter 72,Uncategorized — ravinthatte @ 6:39 am

Chapter 72.  Injuries of the Lower brachial Plexus C8 T1

The chapters included in this blog so far for the treatment of injuries to the brachial plexus have covered (1) the general principles including the treatment of injuries to the nerves and their classification chapter 69; (2) treatment of injuries to the plexus of a global nature (when all the roots are avulsed or ruptured) chapter 70 and (3) the treatment of injuries to the plexus at the level of the C5 C6 roots and the their nerves chapter 71. This chapter deals with injuries to lower brachial plexus involving it’s C8 T1 roots.

The compiler of this blog is indebted to Dr. P.S. Bhandari a leading plastic surgeon specialising in the treatment of injuries and other pathologies of the brachial plexus as well as peripheral nerves and who works at the Brij Lal Super-speciality hospital and research centre in Haldwani, Nainital in the Uttarakhand state of India for helping in the writing of this chapter on the injuries to the lower brachial plexus (C8 T1). Dr. Mukund Thatte plastic, hand and brachial plexus surgeon from the Bombay hospital Mumbai India has as in the previous chapters been of equal help in this chapter as well. In addition, because of the intricate nature of the nerve supply of the muscles of the fore arm Professor Maksud of the department of plastic surgery at the Lokmanya Tilak hospital of Mumbai India as well as his two younger colleagues, Drs. Saumil Shah and Sanket Ekhande were a great help in ‘brain storming’ and the anatomical cadaveric dissections of the relevant nerves as well as for the photographs and drawings included in this chapter.

The compiler of these short notes is aware that such an anatomical division as narrated in the first para for the treatment of these injuries is not ideal because in reality not infrequently the nature of injuries is not clearly defined in terms of the location of the injury and is of a mixed nature across the roots. However, this arrangement was followed with the thought that it would be easier for a post-graduate to grasp the subject if it was divided in separate parts. It was also the impression of this compiler that the available texts are somewhat jumbled up with the assumption that the readers would be able to sort out the information which they needed. The compiler of these short notes differed from this assumption when he approached these texts as a postgraduate would do.

The other caveat that was followed was also somewhat different in that procedures which involved re-innervation from extra or intra plexal sources were mostly included in the previous chapters. This too does not conform to all the protocols. For example, in the chapter on global palsy one surgeon who was invited to contribute includes a free muscle transfer with micro neural as well as micro vascular repair as a primary treatment. But that was only an exception. Free muscle transfers as well as local muscle transfers to overcome deficiencies will be covered in a later chapter. This is not to mean that these procedures are meant only for salvage after the original re-innervation did not yield satisfactory results and therefore that option of a primary free muscle transfer will also be covered at that time.

The treatment of lower brachial plexus lesions in one respect differs from those of the upper part of the plexus in the distances involved in the process of re -neurotization. As examples (1) the transfer of the spinal accessory nerve to the suprascapular nerve supplying the supra-Spinatus muscle that is proposed to be re-innervated or (2) the re-innervation of the biceps muscle by borrowing from the adjacent ulnar nerve to the branch of the musculocutaneous nerve that supplies the biceps muscle near its hilum do not involve more than a distance of few centimetres for the reinnervation to succeed. This is not true of the injuries to the lower brachial plexus as explained below.

The nerves affected in the paralysis of the C8 T1 roots, either avulsions or rupture of the nerves that emerge from these roots, leads to mixed results in the ulnar median and radial nerve motor territories because of the way these nerves form. The radial nerve for example is formed by all the roots (C5 to T1) while the median nerve draws its fascicles from C5C6 and C8T1. The ulnar nerve is however an exception in that it is wholly formed by theC8 T1 roots. The ulnar motor supply therefore is completely lost but the effects on the other nerves are more variable because the root values of the branches of these nerves might be from outside the supply from the roots C8, T1. To explain this intricacy a chart is given below of individual supply of muscles and the root values of nerves that supply them. Those which are definitely paralysed are shown in red, those that may be spared are shown in blue and the muscles that are definitely spared are shown in green. The chart begins with the ulnar nerve which is the most affected.

This chart draws its information from a recent edition of Gray’s Anatomy but is not always accurate when the muscles are tested in patients who suffer from injuries to the C8 T1 roots. In fact if one was to consult other standard texts such as by Last or Lister some variation is quite apparent. In the chart below Dr P.S. Bhandari who has a vast experience in the field of these injuries has pointed out this discrepancy by noting the nerve supply that he thinks is correct from what he has seen in his clinical practice. Those observations and highlighted in yellow in the case of pronator quadratus, flexor digitorum superficialis, flexor pollicis longus and palmaris longus muscles.

Flexor carpi ulnaris                                               Ulnar nerve root value C8 T1

Flexor digitorum profundus (ulnar side)          Ulnar nerve root value C8 T1

All palmar and dorsal interossei, C8 T1

Adductor pollicis   C8 T1

Flexor pollicis brevis deep head   C8 T1

The ulnar lumbricals via the deep or other branches of the ulnar nerve C8 T1

The branches of the ulnar nerve which supply the small muscles of the little finger also have the same root value C8 T1

The median nerve

Flexor carpi radialis, median nerve, root value C6 C7

Pronator Quadratus, median nerve, root value C6 C7                          (C8 T1)

Palmaris longus, median nerve, root value C7 C8                                   (C8)

Flexor digitorum superficialis, median nerve root, value C8 T1         (C7 C8 T1)

Flexor digitorum profundus, radial two, Anterior interosseus (AIN) root value C8 T1

Flexor pollicis longus, AIN, root value C7 C8                                             (C8 T1)  

Flexor pollicis brevis, Abductor pollicis brevis, Opponens pollicis and radial lumbricals all by branch of median nerve root value C8 T1

The radial nerve

Extensor carpii radialis longus, Radial, root value C6 C7

Extensor carpii radialis brevis,     P.I.N., root value C7 C8 PIN: Posterior interosseus nerve

Extensor  digitorum                        P.I.N., root value C7 C8

Extensor carpii ulnaris                   P.I.N. root value C7 C8

Extensor indices                               P.I.N. root value C7 C8

Abductor pollicis longus                P.I.N. root value C7 C8

Extensor pollicis longus                 P.I.N. root value C7 C8

Extensor pollicis brevis                  P.I.N. root value C7 C8

Supinator                                           P.I.N. root value C6 C7 (Via separate fascicles?)

Brachioradialis                                 Radial root value C5 C6

(THE BRACHIALIS MUSCLE IN THE ARM IS ALSO MENTIONED HERE BECAUSE ITS NERVE A BRANCH OF THE MUSCULLOCUTANEOS NERVE WITH IT’S ROOT VALUE C5 C6 IS FREQUENTLY USED TO REINNERVATE THE ANTERIOR INTEROSSEUS NERVE ROOT  VALUE C8 T1).

What emerges therefore is the fact that while dealing with these injuries a thorough clinical examination is of great importance and must include examination of muscles which are paralysed and those that are not and to decide if nerves can be borrowed from non- paralysed muscles without causing gross loss of function in the upper arm.

Be that as it may, common clinical experience in injuries to the C8 T1 roots usually reveals that all flexors and extensors of the fingers (including the thumb) all intrinsic muscles of the palm and all small muscles of the thumb and little finger are paralysed. The long radial extensor of the wrist as well as the radial flexor of the wrist are spared which means that the wrist is not normal but functional but the fingers are limp. Of these the small muscles (the crucial intrinsic muscles ) waste rapidly and in most cases are extremely difficult to salvage except in fresh cases involving children or young adults in whom the opposite C7 root might be used to re-innervate the ulnar nerve by way of a nerve graft. These cases are few by far and therefore the surgeon needs to accept the fact that the hand will have to be partially rehabilitated by achieving a pinch action between the index and the middle finger against the thumb.

The anterior interosseus nerve (A.I.N.) also called the million dollar nerve as the name suggests is crucial here because it supplies the long flexors of the thumb as well as the long flexor of the index and the middle fingers (Flexor Digitorum Profundus) and therefore it’s reinnervation if successful will allow a pinch to be formed with the wrist in a position of function (in slight extension) Four prospective nerve donors are available. (1) Nerve to brachialis a branch of the musculocutaneous nerve (root value C5 C6), (2) the nerve to brachioradialis branch of radial nerve (root value C5 C6), (3) and the nerve to extensor carpii radialis brevis if the muscle is not paralysed. The nerve to the intact extensor carpii radialis longus the slightly weaker of the two extensors can also be used if the ECRB is working well.

As to the extensors of the fingers which are supplied by the posterior interosseus nerve the nerve that is commonly used is the nerve to the supinator root value C6 C7 a branch of the radial nerve which leaves the radial nerve carrying separate fascicles as compared the posterior interosseus nerve (P.I.N.) with a root value of C7 C8.

Any treatment therefore will require testing individual muscles confirming that they are not affected and borrowing nerves supplying those muscle without causing too much loss of function. Reproduced below are figures to show how the intact muscles whose nerves might be borrowed without affecting the function of the hand are tested.

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Please find below photographs of dissections in the lower arm and forearm showing the nerves and their course which are affected in the lower brachial palsy as well as nerves that escape the effects of the palsy.

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These figures are self-explanatory with incorporated labels.

Below is reproduced a line drawing of the possible procedures for reinnervation.

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The fascicles of the median nerve on top (Red) The posterior fascicles divided and joined to the nerve to brachialis (Blue) and the flow of the nerve impulse in green in the lower diagram.

Please find below intra-operative and clinical examples kindly supplied by Dr. P.S. Bhandari. They mainly show reinnervation of the anterior-interosseous nerve (AIN), also called the Million Dollar Nerve.

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January 9, 2019

Chapter 71: Upper Brachial Plexus Palsy

Filed under: Chapter 71,Uncategorized — ravinthatte @ 6:34 am

Chapter 71: Upper Brachial Plexus Palsy

Avulsion of C5 C6 roots and/or Rupture (laceration) of their Combined Trunk

The compiler of these short notes thanks Drs. Raja Sabapathi the director of the plastic and microsurgical services and a hand surgeon at the Ganga hospital in Coimbatore a leading plastic surgery centre in India, his associate Hari Venkatramani who in turn was helped by Dr. Dalton Jerome. Equally valuable was the guidance given by Dr Mukund Thatte a plastic surgeon specialising in hand and brachial plexus surgery of Bombay hospital in Mumbai India who was helped by Dr. Amita Hiremath his associate.

The nature of accidents which cause injuries to the brachial plexus is described in detail in chapter 69. To revise this in short, any fall for example usually from a two wheeler where the ipsilateral shoulder is depressed and the neck is severely flexed laterally to the opposite side leads to this condition and as stated in the previous chapter more than fifty percent of such cases involve all roots and/ or trunks of the brachial plexus.(C5 to T1).Because of the acute angle at which the trunk of the of the upper roots(C5 C6) courses down the neck as compared to the lower roots and trunks the injury to this part of the brachial plexus is commoner than the rest in the remaining fifty percent of the cases particularly if the shoulder is in adduction at the time of the impact about 15 percent. In cases where the rider is thrown over the handle bars at the time of the impact and the shoulder is in abduction the lower roots and the trunks are more likely to be affected.

The avulsion of the C5 C6 roots or rupture(laceration) of the upper trunk lead to a paralysis of the supraspinatus and the infraspinatus (suprascapular nerve C5C6) the deltoid (the axillary nerve C5C6) the biceps brachii and the brachialis muscle (both supplied by the musculocutaneous nerve C5C6).

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This mainly leads to absence of abduction and external rotation of the shoulder and inability to flex the elbow which can be improved a great deal by the existing methods of repair (Please see photographs at the end of the chapter before the atlas of the operative steps). The sensory loss on account of this condition occurs over the lateral surface of the shoulder and also involves the index finger and the thumb. The crisscrossing of the nerves within the brachial plexus is such that the sensory loss is usually not severe enough to cause trophic changes.

The modalities for radiological diagnosis to pin point if the injury involves avulsion of roots with or without a pseudo meningocele have been described in chapter 69. The rupture of the upper ensuing trunk and its severity may not be easy to diagnose completely preoperatively and is usually done intra-operative (Sunderland classification chapter 69). In case of a Post Ganglionic injury i.e. rupture intra-plexal repair of a ruptured common trunk of C5 C6 roots such as by excising a neuroma and approximation of the cut ends of the trunk without tension or bridging a ‘net nerve deficit’ by a nerve graft are performed if possible.

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Photographs contributed by Dr. Raja Sabapathi and Dr. Hari Venkatramani, Coimbatore

A common source for the nerve graft is the sural nerve. Its anatomical course is reproduced below by way of a cadaveric dissection.

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This repair helps towards rehabilitation of the other muscles around the shoulder girdle and helps to stabilise the shoulder joint in which the desired movements will occur with greater ease.

This repair also helps improvement in the sensations over the shoulder region and in the hand. However, the surgeon also aims to reinnervate the affected muscle (or muscles) near its hilum by a distal nerve transfer for more predictable results because the reinnervation is faster due to a much lesser distance that the process of reinnervation has to traverse.

The aim of these distal transfers done to rehabilitate a patient with C5C6 lesions are to restore abduction and external rotation of the shoulder and flexion at the elbow. While restoring the flexion at the elbow by reinnervating the biceps the action of supination also comes to be normalised because the biceps is an additional supinator at the radioulnar joint in addition to the supinator proper which is supplied by a branch of the radial nerve (Root Value C7 C8). This is however achieved only if the action of the paralysed biceps improves to over grade 4+. The restoration of the action of the biceps also helps the stabilisation of the shoulder joint.

The supraspinatus as well as the infraspinatus are reinnervated by the spinal accessory nerve (XI) harvested at the level of the middle fibres of the trapezius (The upper third of the Trapezius remains innervated) by joining it to the suprascapular nerve which arises from the upper trunk (C5C6).

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The restoration of the abduction of the shoulder by the deltoid is achieved by reinnervating the anterior division of the axillary nerve (root valueC5C6 via the posterior cord) by the branch of the radial nerve to the long head of the triceps (root value C6C7C8) after it has been ascertained preoperatively that the triceps muscle is functional (at least MRC grade 4).

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Figures photoshopped from Gray’s Anatomy

 Flexion of the elbow is aimed to be restored by borrowing the antero-medial fascicle of the ulnar nerve (root value C8 T1) to reinnervate the branch to the biceps of the musculocutaneous nerve (root value C5C6) and additionally the central fascicle of the median nerve is used to reinnervate the branch of the musculocutaneous nerve to the brachialis. The use of the fascicles of the ulnar nerve were first described by Oberlin while the addition of the fascicles of the median nerve to the nerve to the brachialis was described by Susan Mackinnon.

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All repairs are done without any tension and this is further confirmed by performing passive movements of the shoulder and elbow with the coaptation in view. Should there be any evidence that such movements are causing tension then the patient’s shoulder is immobilised in adduction for four weeks and the elbow is held at 135 degrees flexion, both are then slowly and progressively mobilised.

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Photographs contributed by Dr. Raja Sabapathi and Dr. Hari Venkatramani, Coimbatore

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Photographs contributed by Dr. Raja Sabapathi and Dr. Hari Venkatramani, Coimbatore

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Pictures contributed by Dr. Mukund Thatte and Dr. Amita Hiremath, Mumbai.

The following pictorial atlas gives a step by step description of how the Brachial Plexus is explored.

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These pictures are contributed by Nayana Nayak, clinical associate of Mukund Thatte at the Bombay Hospital, Mumbai.

Notes: Teres minor is an important external rotator of the shoulder joint and has been specifically reinverted by some surgeons using the phrenic nerve, a motor branch of the triceps or the long thoracic nerve if it has escaped the effects of the injury to C5C6 nerves. This is done by re-innervating a branch of the lower subscapular nerve which supplies the teres minor muscle.

It is expected that exposure of the nerves in the upper arm will be included in the next chapter which will discuss injuries to the lower brachial plexus.

October 10, 2018

70. Treatment Strategies in Cases of Pan-plexal Avulsion Injuries of the Brachial Plexus

Filed under: Chapter 70,Uncategorized — ravinthatte @ 11:17 am

70. Treatment Strategies in Cases of Pan-plexal Avulsion Injuries of the Brachial Plexus

(In cases where roots (C5 to T1) are not available for repair at the site).

Though a global or pan-plexal palsy can result from laceration of post-ganglionic nerve roots the present chapter deals only with a palsy where all roots are avulsed from the spinal cord.

The aims and objects of the reconstructive surgeon under the above condition are as follows.

  1. Restore the function of abduction and external rotation at the shoulder
  2. Restore the ability to flex the elbow
  3. Restore extension at the elbow
  4. Restore the flexion and extension at the wrist
  5. To achieve at least mass flexion of the fingers for a grip
  6. Restore extension of the fingers
  7. Get the thumb to move in a position away from the palm to achieve a grip
  8. Restore sensations to the hand.

There are basically two methods to achieve these objectives:

  1. restoration by extraplexal neurotisation of affected nerves for restoring functions of muscles as well as regaining sensations
  2. a combination of extraplexal neurotisation as well as importing free functioning muscles (FFMT) to restore action of muscles.
  3. The nerve reconstruction effort can be done in one stage the results are then observed over some months and the residual deficiencies can be then corrected at a later stage.
  4. The reconstruction is planned in stages to begin with and as the stages are accomplished information on the success or failures of the stages will influence later strategies.

It is generally accepted that the scope and availability of tissue for revitalising all the muscular actions mentioned above is limited. For example, at the wrist an arthrodesis in a position of function will spare FFMTs which then can be used for actions involving fingers. In the case of the thumb though a restoration of active opposition for a grip is ideal, recourse might be taken to get the thumb in a better position by a static procedure (not by an arthrodesis which is usually avoided) but by re-routing a tendon (a tenodesis procedure). At the elbow because the arm falls by its own weight and gets extended passively more attention is paid to flexion at the elbow in a dynamic fashion. Because the actions of the arm are performed with the help of at least some abduction at the shoulder the restoration of active abduction at the shoulder is considered crucial by most surgeons and constitutes the foundation of the rest of the reconstructive procedures distally. There might be cases where as a result of paralysis of muscles around the shoulder particularly in late cases the shoulder might tend to sub luxate in which case a procedure to fix the shoulder in a slightly abducted position of function might become necessary.

In order to compile this chapter, the help of three leading surgeons in India who do considerable work on patients with injuries to the brachial plexus was sought and they were invited to narrate their strategies. Their names are Dr. Anil Bhatia an orthopaedic surgeon from Pune whose practice is restricted to patients with injuries to the brachial plexus, Dr. Mukund Thatte a plastic surgeon and a leading hand surgeon who practices in Mumbai and Dr. Venugopal Purushothaman a leading plastic hand and brachial plexus surgeon from Chennai. All three hail from India.

The material in this chapter does not include procedures to restore sensations to the limb nor does it include secondary procedures which may be employed to correct any residual problems following the primary treatment. These subjects are to be covered in later chapters.

The strategy of Dr. Purushothaman is narrated below with the help of diagrams. The strategy involves restoration of nerve functions by extra plexal nerve sources and does not involve FFM transfers certainly not primarily. In his method the extra-plexal neurotization is done in a single stage with the help of two teams who work simultaneously. The various manoeuvres are narrated below followed by diagrams.

  1. Spinal accessory to the suprascapular nerve. This is one procedure that appears to be common to all the contributors to this chapter. The suprascapular nerve is the first branch of the upper trunk and supplies the supraspinatus muscle a prime abductor of the shoulder, as well as the Infraspinatus, which is an external rotator.
  2. Contra lateral (opposite) C7 root is bridged with a nerve graft (usually sural nerve) and joined to the axillary nerve arising from the posterior cord of the brachial plexus (C5 C6) which supplies the deltoid muscle. This procedure too is done to restore abduction at the shoulder
  3. The same C7 root is also joined with a nerve graft same as above to the nerve to the biceps a branch of musculocutaneous nerve (C5 C6).
  4. A vascularised ulnar nerve graft from the same side is rotated and its distal end is joined also to the contralateral C7 root and its proximal end is joined to the whole of the median nerve (flexors of the wrist and fingers) and is also joined to all motor branches of the radial nerve which supply extensors of the wrist and fingers. In addition, one funiculus of this graft is used to supply the nerve to the brachialis a branch of the musculocutaneous nerve.
  5. The third intercostal motor nerve is used to supply the nerve to the pectoralis muscle the lateral pectoral nerve (C 5 6 7).
  6. The fourth and the fifth motor intercostal nerves are joined to the nerve to the triceps branch of the radial nerve.
  7. The sixth intercostal motor nerve is joined to the nerve to the serratus anterior or the long thoracic nerve.
  8. In the next stage, the thumb is positioned to allow opposition by a static opponensplasty. The tendon used is the flexor carpi ulnaris (FCU) which is detached from its insertion extended in length with a tendon graft such as by a piece of palmaris longus to go around the metacarpal of the thumb and brought in an opposable position.
  9. The flexor digitorum profundi muscles are tagged to each other for a mass action enabling flexion of all fingers.

This completes the re-neurotization. 1, 2, 5, 7 will look after the shoulder 3, 6 will enable elbow movements 4 will look after the movements of the hand and fingers. The diagrams that follow describe in nutshell the procedures undertaken by Dr. Purushothaman.

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Dr. Anil Bhatia performs the reconstruction in one stage. He joins the spinal accessory nerve of the same side to the suprascapular nerve (abduction of the shoulder). He also uses the Phrenic nerve of the same side to join to the posterior division of the lower trunk for extension of the elbow. He then mobilizes the brachial plexus on the affected side in the following manner.

  1. All three upper middle and lower trunk are completely dissected.
  2. The delto-pectoral grove is opened and all the cords with the musculocutaneous nerve are isolated.
  3. The medial cord is traced behind the clavicle till its roots C8 T1 roots and is delivered under the clavicle.
  4. The posterior division of the lower trunk is now visible.
  5. That division is split off the lower trunk.
  6. The opposite C7 is then isolated and traced distally as far as possible till the converging elements of the upper and middle trunks.
  7. The branch to the serratus anterior is divided to allow for its transfer across the neck.
  8. The C7 contralateral root is then transferred across the neck, sometimes behind the oesophagus or via the carotid sheath and brought as much as possible on the affected side or at least near the midline near the medial border of the sternomastoid close to the supra-sternal notch.
  9. The mobilization of the anterior division of the lower trunk on the affected side allows it to reach near the supra-sternal notch where the contralateral C7 root now lies on adduction of the arm.
  10. If this approximation is difficult the humerus is shortened to facilitate upward and medial movement of the anterior division of the lower trunk.
  11. The opposite C7 root is now joined to the anterior division of the lower trunk (flexion of fingers).
  12. In addition the medial cutaneous nerve of the fore arm already divided at its origin to facilitate the mobilisation of the anterior division of the medial cord is used as a conduit to reinnervate the musculocutaneous nerve via the opposite C7 root. This can be supplemented by an additional conduit of a sural nerve graft between the C7 root and the musculocutaneous nerve for flexion of the elbow by way of the biceps.

In summary: In one procedure the abduction of the shoulder the flexion and the extension of the elbow the flexion and extension of the fingers is provided for.

The figures below conform to what Dr. Bhatia does in one stage for a global avulsion palsy.

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Dr. Mukund Thatte performs the reconstructive procedures in four stages after confirming that no reconstruction is possible at the level of the roots.

First stage

  1. Spinal accessory nerve to the suprascapular nerve for abduction at the shoulder.
  2. Opposite hemi C7 root (posterior half) to the lateral cord for reinnervation of the biceps and pectoralis major plus sensation in the Median territory via lateral root of the Median which is a terminal branch of the lateral cord.

Second stage

  1. Free functional muscle transfer (FFMT) of Gracilis muscle across the volar surface of the elbow. The transferred muscle is innervated by the intercostal nerves and vascularised through the thoracodorsal vessels. The muscle is sutured to the tendons of the flexor digitorum profundus as well as flexor pollicis longus.
  2. One intercostal nerve is used to innervate the triceps muscle.
  3. Sensory branches of Intercostals joined to Ulnar.

Stage three

  1. Wrist fusion if there is no recovery of extensors

Stage four

  1. Opponensplasty to improve function in the hand from the recovered flexor pollicis longus from the earlier neurotization

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June 15, 2018

69. Injuries of the Brachial Plexus

Filed under: Chapter 69 — ravinthatte @ 6:06 am

69. Injuries of the Brachial Plexus

General principles

The word brachial has its root in the Latin word Bracchium to mean an arm the plural of that word is Bracchia. The word plexus refers to the complex arrangement of the nerves which supply the arm both its sensations and the motor power to the muscles that move it. The plexus is formed by the cervical (C) 5678 and thoracic (T) 1 mixed spinal nerve roots formed by the axons of the sensory dorsal root ganglion (DRG) and the motor roots of the anterior horn cells (AHC).

Slide1

The format of this and following chapters

This and the following chapters dealing with injuries to the brachial plexus aim at providing a guide to post-graduate students in Plastic and Orthopaedic and Hand surgery in a practical and readymade format to help them organise their thoughts before appearing for their examinations as well as prior to assisting or undertaking surgery on the brachial plexus. This chapter only describes the general principles as indicated in the title. In the event the material in these chapters is not organised in the traditional manner. The description of the anatomy of how the plexus forms (roots trunks divisions and cords) and the various individual branches emanating from the plexus are dealt with and described as and when specific clinical applications are presented. For example, the next chapter will discuss the treatment for a global palsy where all roots of the plexus are avulsed and the relevant anatomical diagrams will be included for ease of understanding.

Acknowledgements

These chapters would not have been possible but for the enormous help given by Drs. Mukund Thatte and Maksud Devle both academic plastic surgeons from Mumbai, India.

A very brief note on history

The history of the treatment of injuries to the brachial plexus reveals that the progress was extremely slow or almost non-existent till the seventies of the last century. In fact, a pioneer in the field of nerve injuries prior to that period had lamented that the treatment of injuries to the brachial plexus is not likely to see any successful outcomes in the foreseeable future.

The element of avulsion in injuries to the brachial plexus

One of the possible reasons for this pessimism mentioned in the previous paragraph might have been the crucial difference between the injuries to the brachial plexus and the other peripheral nerves. In the brachial plexus there is a possibility of an avulsion of the roots of nerves from the spinal cord prior to their emergence from the bony vertebral column before forming (the brachial) plexus. For all practical purposes at present, this avulsion injury cannot be treated at the site of avulsion by any form of neural repair in the hands of a majority of surgeons in this speciality, though some attempts are now underway to achieve this repair. Injuries causing avulsions of all the nerves C5, 6, 7, 8, T1 which together form the brachial plexus resulting in a flail and insensate limb is called a global palsy and unfortunately constitute more than fifty percent of all injuries in the supraclavicular area. Rarely in post-traumatic injuries all nerves can be lacerated beyond the ganglion and can also lead to a global palsy. An avulsion injury might be also partial involving only some nerve roots and therefore results in a paralysis of only some muscles and loss of sensation in the area of the nerve supply.

Slide2

Nomenclature

Traditionally these avulsion injuries are called ‘pre-ganglionic’ because the sensory roots of the nerves have their ganglia located outside the spinal cord. The motor root however emerges from the grey matter directly. Traditionally the term pre-ganglionic is used for the motor component of the injury as well. The terms supraclavicular and infraclavicular are also frequently used in describing these injuries. Most infraclavicular injuries involve the peripheral parts of the brachial plexus at the level of the cords and the nerves ensuing from the cords to the arm. Post ganglionic injuries can in the supraclavicular areas will involve the trunks and divisions. The terms extraplexal and intra plexal are used to describe the nature of repair. When the injury to the plexus is partial some nerves from the undamaged part of the plexus which can be spared without causing too much morbidity are used to neurotize the damaged nerves. This is an intra-plexal form of repair. When no such intraplexal nerve is available as happens in a global avulsion injury (C5678 T1) nerves which do not form a part of the brachial plexus are used to help in the repair to neurotize the affected nerves of the brachial plexus and this is called an extra-plexal repair. Such extra plexal nerves can also be used to neurotize muscles transferred as a free functioning muscle to restore function (please see paragraph towards the end of this chapter).

The diagnosis

The diagnosis of an avulsion injury leading to a completely flail limb or a partially paralysed arm is made by (1) the history of a high velocity accident in which the shoulder was forced down wards and the head and neck are forced to the opposite side. In a vast majority of cases the injury is caused by a heavy fall from a ‘two-wheeler’ and the injury is “closed” in nature.

Slide3

(2) by total lack of clinical recovery and the electro diagnostic studies of the muscles in the affected limb in three months. In fact, the electro-diagnostic study might show deterioration by an increase in the appearance of spontaneous fibrillation in the affected muscles. (3) by radiological investigations such as the appearance of a pseudo meningocele at the site where the nerve was avulsed.

Slide4

The M.R.I. is considered the most appropriate for this purpose. See above (4) A C.T. myelogram is the other option to identify the herniation of the meninges where the nerves have been avulsed. (5) a plain radiograph of the area which shows fractures of the bony vertebral column at the suspected site of avulsion can also indirectly contribute in the diagnosis of injuries to the nerves at the spinal level. Plain X-rays can also diagnose fractures involving the shoulder and other joints in the arm as also a raised diaphragm indicating Phrenic nerve injury and this will influence the treatment undertaken in the surgical rehabilitation of the affected arm. A tentative period of three months is mentioned above as a general consensus.  Reconstructive procedures are usually begun at this time. However in a confirmed (by MRI and electrophysiology) five root avulsion injury with no progress it can start earlier.

Basic principle in the treatment of avulsion injuries of all roots of the brachial plexus

Because no recovery is possible in the avulsed nerves these injuries will require to be treated by bringing in extra-plexal tissue for example a transfer or rerouting of an unaffected nerve in the vicinity, the sacrifice of which will not cause any gross morbidity due to the loss of power in the muscle which it supplied originally or cause unacceptable area of anaesthesia after its sacrifice. As an alternative a vascularised muscle as a free flap can be brought in which can be neurotised by an unaffected extra-plexal local nerve. This muscle is used to re-establish the most desired action or actions that the surgeon feels are crucial in the rehabilitation of the patient. More than one muscle might be used in stages to achieve the desired result at different joints. The conditions mentioned in the earlier description while using a nerve alone and the possible morbidities that it may cause apply here as well (details of such procedures will be given in later chapters for ease of understanding).

Injuries to the plexus with open wounds

As opposed to the above where the final diagnosis must wait, in cases of open injuries caused during accidents or resulting from attacks by sharp instruments the decision to repair the damaged nerves outside the bony canal is easier. If the patient is stable or is rendered stable after the treatment of life saving injuries the wound can be explored thoroughly, the lacerated nerves can be identified and repaired after vascular reconstruction is performed if required.  Repair of torn muscles can be undertaken simultaneously. Here too the surgeon is helpless in repairing avulsions of the nerves from the spinal cord though perhaps reconstructive surgery can begin early in such cases because the diagnosis is made on the table. If the patient is unstable, the injuries to the nerves are mapped, torn ends of the nerves can be approximated with radio opaque vascular clips to prevent retraction and the patient can be explored early by what is called a ‘subacute exploration’. Traditionally gunshot injuries as well as penetrating punctured wounds are treated more conservatively to allow a clearer picture to emerge regarding the exact damage caused to the brachial plexus.

Injuries to the nerves of the brachial plexus which do not include an element of avulsion.

In addition to avulsion injuries there are three other types of closed injuries that the nerves can suffer outside of the bony spinal column. They are based on the classification described by Seddon originally described for other peripheral nerves. Slide14 In the severest form the traction injury can tear the nerve and the nerve loses its continuity. This is called neurotemesis.

The stretch injury can also disrupt a nerve by tearing the axons without losing its apparent continuity because of the sheaths that envelope the nerve can be fully or partially intact. This in the Seddon’s classification is called axonotemesis. Sunderland classified this type of injury further by stating that the damage to the investing layers of a nerve played a part in the severity of the effects of axonotemesis. Slide15 The investing layers are (1) endoneurium which covers the individual axon (2) perineurium which encloses a group of axons or fascicles (3) and the epineurium which invests a group of fascicles or a nerve. In the Sunderland classification axonal damage with an intact endoneurium has the best chances of recovery. Then on, the successive damage to the endoneurium as well as damage to the perineurium delays the recovery of the nerve proportionately.

 

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The nature of recovery in axonotemesis might be patchy and the surgeon usually waits for some months before ultimately deciding to reconstruct the nerve or to undertake reanimation of the affected muscles by way of plexal constituents when elements within the plexus are available and can be used without significant morbidity or by extraplexal sources by the principle explained in the cases of pan-plexal avulsion. The element of devascularisation of the nerve in closed injuries is difficult to judge. The Sunderland’s classification of axonotemesis is sound but the recovery of the nerve must be evaluated by way of clinical and electro-diagnostic methods. However, at the time of surgical exploration the Sunderland classification can come to the rescue of the surgeon by the examination of the nerve under magnification allowing him to choose the nature of surgery depending upon which investing layers are damaged. A neuroma at the site of the injury will need a linear epineural incision to expose the neuroma’s interior to find out if the whole or any part of the nerve is in continuity. Intra operative electrical stimulation of the nerve and its effect on the muscles that the nerve supplies in the form of contraction help a great deal in the diagnosis of the state of the nerve. Depending on the findings of these observations a repair can be performed after ascertaining the integrity of the investing layers of the nerve.

Slide9

In the third category the axons suffer a temporary loss of function and do not suffer any significant cellular damage. The effects of this condition wane off rapidly. This condition is called neuropraxia in the Seddon classification. The stretching force in this condition is not very severe as revealed by the history and observation for a few hours will show recovery in the patient’s condition.

A paradox

One very important difference in the loss of the function of the muscles as opposed to loss of sensations following avulsion injuries to the brachial plexus needs to be noted. The sensory neuron cell bodies (dorsal root ganglion) of the sensory axons lie outside the spinal cord and therefore even though the sensory roots are avulsed from the spinal cord the ganglionic cell bodies remain intact and therefore Wallenerian degeneration does not extend beyond the ganglion in the affected sensory nerve roots. As a result, though the arm is insensate investigation such as sensory nerve action potential (SNAP) denoting the speed of the sensory electrical impulse remains normal because the ganglion is intact confirming that the injury is in the nature of an avulsion proximal to the ganglion (Pre-ganglionic). This paradox does not occur on the motor side where the Wallenerian degeneration proceeds up to the motor neurons in the spinal cord. Here the electromyogram will show fibrillation at rest and inadequate response to direct stimulation of the muscles and or attempted voluntary contraction as the muscle is paralysed and later degenerates following the loss of its nerve supply.

 

Advances in the treatment of injuries to the brachial plexus 

The progress in the treatment for the effects caused by the injuries to the brachial plexus gathered speed in the seventies of the last century owing to the ‘die hard’ attitude of the surgeons and the development of optical instruments which allowed great magnification of the parts being operated on. The development of fibreoptic light which was brighter less traumatic and could be carried by cables helped a great deal in this effort. Simultaneously fine surgical instruments and micro-sutures came to be developed. On this background Millesi first described (1977) the possibility of repairing fascicles instead of co-opting the cut ends of the whole of the nerve arbitrarily. Slide16 This fascicular repair was applied to the repair of the fascicles of a damaged nerve as well as when a nerve graft was co-opted to repair a gap in the nerve. The same principle of fascicular repair could be used when a cut end of an intact nerve was used as a new conduit to re-neurotise an affected nerve in its distal part or at the time of re-neurotisation of a free muscle transfer.

Slide10

In recent times the repair of nerves has been undertaken with the help of biological tissue adhesives after orienting the cut ends in their normal axis. The tissue adhesive can also be used to bind the cable grafts in bundles.

Common extra-plexal tissue used in the treatment for rehabilitation of injuries to the brachial plexus.

The following nerves can be utilised as extra plexal donors. (1) The spinal accessory cranial nerve (2) The Phrenic nerve (3) The cervical nerves (4) The intercostal nerves (5) The C7 nerve root from the opposite side. (7) The hypoglossal nerve has also been used. If these nerves are found to be not long enough to target the recipient nerve then the repair is accomplished with the help of nerve grafts between the above extraplexal nerve and the recipient nerve damaged in its proximal part.

Source of Nerve Grafts

The two most frequently used nerves to harvest nerve grafts are the sural nerve in the lower leg and the radial cutaneous nerve in the forearm (for the course and approach to harvesting of the radial cutaneous nerve please see the previous chapter on ‘compressive neuropathy of the radial nerve).

Slide11

Both cause only a little morbidity after their harvest. In addition the medial cutaneous nerve of the arm as well as the medial cutaneous of the forearm can be harvested for the purpose of obtaining nerve grafts and also result in very little morbidity. Typically these are all used in a total palsy. In partial injuries the Sural is favoured.

Slide12

Though not extraplexal the ulnar nerve has also been used as a graft. It can also be used as a vascularised graft both pedicled as well as by way of a free microvascular transfer. The sacrifice of the paralysed ulnar nerve is a compromise to achieve rehabilitation in areas supplied by the median nerve.

Free functioning muscle transfer (FFMT)

In global or pan-plexal palsies in order to make the paralysed arm functional at multiple levels, the shoulder the elbow the wrist and the fingers; one or two FFM transfers are undertaken because neurotization by way of extra plexal nerves, for example for the shoulder, does not suffice for all the other areas mentioned. The commonest muscle used for this purpose is the Gracilis muscle which is strong but not bulky and has a long tendon and its harvest leads to a scar which is hidden on the medial side of the thigh.

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Results

Generally speaking the results of surgery in the treatment of injuries to the brachial plexus by whatever cause are better in children than adults. Treatment in adults above the age of fifty are generally poor though treatment can be undertaken after counselling and advise. The results are generally speaking superior when treatment is begun within three to six months of the injury irrespective of the nature of the injury.

 

 

April 3, 2018

68. Compressive Neuropathy of the Radial nerve

Filed under: Chapter 68,Uncategorized — ravinthatte @ 10:26 am

68. Compressive Neuropathy of the Radial nerve

The compiler of these short notes thanks Dr. Anil Bhat, Professor and Head, Department of Orthopaedics, Kasturba Medical College and Manipal Academy of Higher Education, for scrutinising the manuscript, general guidance and some illustrations. He has done notable work on compressive neuropathies in the arm. The cadaveric dissections were performed by Dr. Saumil Shah and Dr. Chirag Bhansali both senior residents in the department of plastic surgery at the Lokmanya Tilak municipal hospital and college Mumbai under the supervision of Dr. Maksud Devle a professor in the same department. Dr. Natarajan the head of the department of anatomy kindly allowed these dissections.

1.   The radial nerve receives contributions from the posterior cord of the brachial plexus from which it arises but also from all three trunks superior middle and inferior of the brachial plexus and therefore its root value is C5 6 7 8 as well as T1. It gives branches to all three heads of the triceps muscle as it emerges from the lower triangular space (Fig. 1).

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The nerve is accompanied at its exit from this space by the brachial artery. It then passes behind the humerus along its spiral groove and can be damaged at this site by fractures in the middle third of the humerus (Fig. 2 and 3).

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2.   In some of these cases of fractures of the humerus, the nerve can also be damaged during surgery when the fractures of the humerus are reduced and fixed by appliances. Rarely the radial nerve may be affected by a tardy palsy when the fracture comes to unite even though the nerve is in continuity. The spiral groove is also the area where the nerve can get compressed by a sharp edge on which the arm rests when the arm is extended and abducted during deep sleep or in a state of inebriation. In popular parlance, this is called the Saturday night palsy where all extensors of the wrist and fingers are paralysed. The condition usually recovers spontaneously though in the interim the hand needs to be splinted, at least at the wrist (in extension) to allow actions by the flexors.

3.   From here on the nerve pierces the lateral intermuscular septum to enter the anterior compartment and lies in a furrowed space between the brachialis on the medial side and the brachioradialis and then the extensor carpi radialis on the lateral side. It is in front of the lateral condyle of the humerus that it divides into the superficial and the deep branch also called the posterior interosseous nerve (PIN) and it is these two nerves that may suffer a compressive neuropathy which is the subject of this chapter. The superficial branch is sensory and is called radial sensory nerve (RSN). The PIN is purely motor. Please see figures 2 and 3 above.

4.   The RSN travels along the radial border of the forearm below the brachioradialis. Half way down in the middle of the forearm it becomes subcutaneous between the brachioradialis and the extensor carpi radialis brevis by piercing the deep fascia and it is at this site that pain along the nerve can be elicited by tapping to produce exaggeration of symptoms of its compressive neuropathy (Fig. 4 and 5 below). It divides into two main branches 5 centimetres proximal to the radial styloid one of which supplies the dorsal and the radial surface of the thumb and the other called the major dorsal branch supplies the dorso-ulnar surface of the thumb as well as the dorsal radial aspect of the index finger. Another branch supplies sensations to the dorso-radial surface of the index and the dorso ulnar surface of the long finger.

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Actions involving strong pronation and simultaneous ulnar deviation puts this nerve on maximum stretch and any profession involving such repeated action predisposes to a neuropathy of the nerve. Repeated use of a heavy screw driver is an example. It is worth noting that this action results in approximation of the brachioradialis and the extensor carpi radialis brevis which might compress the nerve as it emerges from under the deep fascia leading to repeated ischemia. In modern times a variety of wrist and forearm bands are used in many a sport as also in activities such as lifting weights in the gymnasia. This together with tight wrist watch belts or heavy bangles that Indian women wear and may cause friction and contribute to the compression.

The condition produces pain or paraesthesia along the nerve and its sensory distribution and can rarely lead to loss of sensations. The pain is exacerbated when the nerve is tapped as well as when the forearm is pronated and flexed ulnar wards at the wrist.

Slide6
Fritz de Quervains

One branch of this nerve is in close approximation to the first extensor compartment of the wrist (Fig. 4) which is known to undergo an inflammatory pathological constriction leading to pain and poor gliding of the long extensor and abductor of the thumb. The condition is named after Fritz de Quervains (1868-1940) who was mainly known for his study of thyroid disease but also described an inflammatory condition of the tendons in the first extensor compartment.

A neuropathy of the radial sensory nerve might coexist with de Quervains disease because the obstructed first compartment and the consequent inflammation may temporarily affect the nerve. The diagnosis is made by tapping over the first extensor compartment when pain usually does not spread along the distribution of the nerve if the condition is restricted to the first extensor compartment. An improper release of the first compartment without identifying and securing the nerve can however lead to consequences such as a painful neuritis or anaesthesia in the distribution of the nerve.

The entrapment of the radial sensory nerve can be treated surgically by an incision not more than 3 centimetres in length placed vertically over the course of the nerve at about the junction of the upper two thirds and the lower one third of the flexor aspect of the forearm (Fig. 6).

Slide7

In view of the small size of the nerve some form of magnification is advised. The first step is to identify the musculotendinous junction of the brachioradialis muscle. Then by retracting the skin posterio-laterally the extensor carpi radialis brevis tendon can be visualised. The wound is undermined proximally and then distally and the fascia between the two muscles is identified by inserting a small right-angled retractor on either side. The nerve may be seen emerging in the lower end of the incision. If not the fascia between the two muscles is incised and the two muscles are retracted in their proximal part and in the bed created by this retraction the nerve can be visualised. The incision in the fascia is then extended distally and then proximally for about 10 centimetres and this will suffice to completely decompress the nerve. Occasionally a part of the brachio radialis muscle might have to be resected along its vertical direction. Only the skin and subcutaneous tissue are closed leaving the deep fascia open. A supporting dressing across the wrist joint with a thin plaster slab is employed to give post-operative rest to the part.

5.   The posterior interosseous nerve (P.I.N) is the larger of the two branches of the radial neve and arises in front of the lateral epicondyle of the humerus but unlike the sensory branch enters the posterior compartment of the forearm between the two heads of the supinator (humeral and ulnar) muscle (Fig. 12 and 13 see below). But prior to that it may encounter a fibro-tendinous arcade originating from the radio humeral joint which merges with fascia covering the supinator muscle (Fig. 7 and 8). This structure is named after Fritz Frohse (1871-1916, German anatomist).

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6.   After emerging from the supinator muscle the nerve divides into a superficial and a deep branch. The superficial branch supplies the extensor carpi ulnaris the extensor digiti communis and the extensor digiti quinti muscles. The deep branch supplies both the long and short extensor of the thumb and its long abductor as well as the additional extensor to the index finger (indexus proprius). Prior to crossing the elbow the radial nerve supplies the brachialis the anconeus and the brachioradialis. The P.I.N. passes through a tunnel like structure near the elbow. The tunnel’s floor is formed by the capsule of the radio-ulnar joint. The tunnel’s medial wall is formed mainly by the tendon of the biceps muscle and also the brachialis. It’s lateral wall is formed by the brachio-radialis and the long and short extensors of the wrist. Of these the brachioradialis crosses across the tunnel over the nerve from the lateral to the anterior side partly forming the tunnel’s roof. The arcade of Frohse mentioned earlier in the preceding paragraph is also adjacent to this tunnel but its location might vary. The nerve can get compressed in this tunnel because of fibrous bands in between the two heads of the supinator muscle. Gray’s anatomy states that the nerve can also get compressed here by the sharp edge of the extensor carpi radialis brevis, ECRB (Fig. 9) or a leash of vessels from the radial recurrent artery which supply the brachioradialis muscle as well as the extensor carpi radialis longus muscle ECRL (Fig. 10).

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The leash of vessels is probably named after Henri A.K. Henry also wrote the well known book the Extensile exposures of the extremities (Fig. 11).

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7.   The main symptom of the radial tunnel syndrome is pain and paralytic effects of the muscles that the P.I.N supplies are rare except when the compression is severe or in post-traumatic cases where the nerve might be damaged within the radial tunnel. In non-traumatic cases the pain is classically produced by pressure over an area between the brachioradialis and the extensor carpi radialis longus. Pain is also caused when pressure is applied over the supinator when the forearm is being supinated. To rule out any pressure on the undivided radial nerve pressure is applied above the elbow between the tendon of the biceps and the origin of the brachioradialis just above the elbow when pain will not be felt. The diagnosis of the radial tunnel syndrome is mainly clinical and electrodiagnostic methods are not useful. Infiltration with local anaesthetic agents sequentially can help locate the area of entrapment.

Surgery to treat the radial tunnel / P.I.N.syndrome is performed by an incision along the posterior border of the brachioradialis muscle marked by asking the patient to flex the elbow in the mid prone position against resistance. The incision about 10 centimetres will expose the extensor carpi radialis longus (E.C.R.L.) on the lateral side and the brachioradialis on the medial side.

A very thin nerve the posterior cutaneous nerve of the fore arm can be identified here and should be saved. The area between the two muscles is occupied by a fascia which is incised sharply by retracting the two muscles. Further retraction will reveal vessels straddling the two muscles which are cauterized. A plane is developed between the two muscles above and below by blunt dissection with a finger. In the area thus created can then be seen both the superficial and deep (P.I.N.) branches of the radial nerve. The P.I.N. here can be seen entering the supinator muscle. The humeral superficial head of the supinator is then stripped off or incised over the humerus to release it and take away the compression of the P.I.N. The detached head of the muscle is then held and any fibrous bands between it and its deep origin are then cut away. At this stage a finger can be introduced in the proximal part of the incision at the level of the elbow and burrowed higher to take away any constricting elements around the main trunk of the radial nerve. Some surgeons as a form of caution detach the origin of the long radial extensor of the wrist (E.C.R.L.) from the lateral epicondyle just in case the condition was only one of lateral epicondylitis (Fig. 14-18 below).

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All above photographs courtesy Dr. Anil Bhat.

February 19, 2018

67. Compressive Neuropathy of the Ulnar Nerve

Filed under: Chapter 67,Uncategorized — ravinthatte @ 4:32 am

67. Compressive neuropathy of the ulnar nerve

The compiler of these short notes acknowledges the help of Drs. Mukund Thatte from Mumbai and Rajendra Nehete from Nashik in India both plastic surgeons with special interest in surgery of the hand in writing this chapter. The cadaveric dissections were performed by Professor Maksud Devale assisted by Sumit Hadgaonkar as well as Neeraj Bhaban both senior residents; all from the department of plastic surgery at the Lokmanya Tilak municipal medical college and hospital in Mumbai. Professor Natrajan the head of the department of anatomy of the above institutions was kind enough to allow the dissections.

  1. The ulnar nerve is a mixed nerve and is a terminal branch of the medial cord borrowing its fibres from the C8 and T1 nerve roots.

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  1. Like the median nerve it is vulnerable to compression as it traverses across the elbow and the wrist though the sites in the case of the ulnar nerve are different. Approximately 8 to10 centimetres above the medial epicondyle of the humerus the ulnar nerve lies posterio-medial to the brachial artery and anterior to the medial head of the triceps and is posterior to the medial inter-muscular septum. This septum is continuous from the medial epicondyle to the coraco-brachialis muscle. A fibrous arcade extending from the intermuscular septum and made of the deep brachial fascia covers the ulnar nerve at this site and may compress the nerve. This fibrous arch was described by John Struthers the Scottish anatomist and is named after him. The previous chapter on compression of the median nerve around the elbow also included a similar ligament arising from an abnormal origin of the pronator teres from the humerus which too was described by John Struthers and is named after him.

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Dissection specimens courtesy Maksud Devale, Sumit Hadgaonkar and Neeraj Babhan.

  1. From here on the ulnar nerve lies behind the medial epicondyle and is medial to the olecranon. This is the cubital tunnel the roof of which is formed by a tough and somewhat taut fascial layer which extends from the origin of the flexor carpi ulnaris on the humerus named after Osbourne. Barring this fascial structure the nerve for all practical purposes is subcutaneous at this point. From here the ulnar nerve enters the forearm between the humeral and ulnar head of the flexor carpi ulnaris.

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  1. All the structures mentioned above may be associated with a compression of the nerve the commonest probably being in the cubital tunnel and this is the second most common compressive neuropathy after the carpal tunnel syndrome involving the median nerve in the arm described in the previous chapter.
  2. While taking the history of the patient suspected of having compression of the nerve around the elbow, past injuries around the elbow joint should be enquired into. This includes injuries or fractures around the elbow. Any occupation involving movements which would lead to a valgus stress should also be enquired into and noted. Rarely a single episode of a severe twisting injury or a hyper extension injury can lead to an ischemic episode leading to neuritis and which might resemble later as a cubital tunnel syndrome. The symptoms usually begin with tingling and numbness in the little and ring fingers accompanied by pain and tenderness in the medial half of the elbow particularly over and around the medial epicondyle and is severe when the nerve is pressed upon in the humeral sulcus or the cubital tunnel. As the condition progresses the weakness of the ulnar intrinsic muscles can lead to clumsiness in actions involving adduction of the thumb and disturbance of proprioceptive actions. Overtime the wasting of the muscles on the ulnar side of the palm becomes quite evident. A Tinels sign is almost always positive from the beginning. Active flexion of the elbow against resistance causes pain at the site and a combination of local pressure and the flexion manoeuvre up to sixty seconds leading to severe pain is conclusive of the diagnosis in a vast majority of cases. In early stages conservative treatment with splints anti- inflammatory agents and a temporary change in the job description may help the condition. Soft padding around the elbow to prevent trauma or counselling on how to prevent certain actions can also give relief
  3. As with the compressive neuropathy of the median nerve at and around the elbow a differential diagnosis of the exact cause of the compression of the ulnar nerve around the elbow may not be always possible because the nerve though compressed in the cubital tunnel might also have other contributing factors for example a pincer action of the two heads of the origin of the flexor carpi ulnaris muscle or a fascial band above the elbow called the Struthers ligament. (Please see para2) All the hard and soft parts in this area develop from modification of the same mesenchymal mass and the condition might be a single phenotype with adjoining abnormalities. This probably has a bearing on the surgical procedure that is employed where a complete exposure of the nerve above and below the elbow is safer from the point of view of giving a final and a lasting result. Generally speaking the results of surgery to decompress the ulnar nerve around the elbow are not as satisfactory as after the release of the carpal tunnel syndrome and for this reason nerve conduction studies play an important role in locating the compressive lesion more accurately or to rule it out and arrive at a diagnosis of a non-obstructive neuropathy
  4. Compression of the nerve and the consequent symptoms and signs which result from reduction of the space in the cubital tunnel following injuries such as fractures are outside the description given in the preceding paragraph and form a distinct entity. A sequestrum, osteophytes or a shallow sulcus following a malunion forcing the nerve to displace\sub-luxate outside the tunnel during flexion among other things can play a part in the ensuing pathology also called a tardy palsy. In such cases an anterior transposition of the nerve after adequate decompression of all offending structures around the cubital tunnel is considered the best possible treatment. The question as to if a sub muscular placement is better than a subcutaneous\sub fascial placement when the nerve is transposed is a matter of debate though the subcutaneous\sub fascial placement is by-far the simpler of the two options. As explained in the previous paragraph the procedure of anterior transposition must ensure a fair amount of mobilisation of the nerve so as to eliminate any possible compression by causes enumerated earlier such as fibrous bands (ligament of Struthers) above the elbow and the pincer action of the dual origin of the flexor carpi ulnaris at the elbow. A medial epicondylectomy can be performed at the time of the anterior transposition if found necessary. Generally speaking an in-situ decompression with a limited incision is not favoured because should it fail subsequent surgery to transpose the nerve becomes that much more difficult. Localised lesions above and at or below the elbow with a normal capacious cubital tunnel are uncommon and have to be proved by conduction studies as mentioned earlier.
  5. The incision for the procedure is vertical and is centred on a point between the medial epicondyle and the olecranon and extends about eight cm. superiorly. It is most convenient to expose the ulnar nerve first in the ulnar sulcus behind the medial epicondyle and then trace it upwards and in so doing identify a cutaneous branch of the antebrachial nerve and retract it out of harm’s way. The medial intermuscular septum is next identified which lies anterior to the nerve and any fascial structures going across the nerve from the septum are released including any offending fibres of the septum itself. This is the area purportedly of the Struthers ligament. The nerve is then followed downwards into the cubital tunnel and its passage through the pronator\flexor origin is inspected for any compressive pathology and if present this is released. At this point the nerve is inspected for any subluxation out of the cubital tunnel while flexing and extending the elbow. The tunnel itself is inspected for any post traumatic artefacts or an abnormally large medial epicondyle. The artefacts are cleared and a medial epicondylectomy can be performed at this stage if indicated. If the cubital tunnel is shallow and if this shallowness is responsible for the subluxation of the nerve  a decision is taken to transpose the nerve anteriorly.  In so doing the connective tissue around the nerve is kept intact so as to preserve its blood supply most of which runs along the nerve and this is best done by retracting the nerve by a soft catheter around it. As the ulnar nerve gets gently retracted, its branches from its posterior surface to the flexor carpi ulnaris and the ulnar profundus muscles come into view. They need to be preserved if necessary by gentle teasing and mobilisation. A thorough distal inspection of the nerve is then performed and any fibrous bands likely to impinge on the nerve in its new transposed position are cut away. In order that the nerve does not regress to its earlier position the soft tissue under the skin flap is sutured to a part of the anterior periosteum of the medial condyle to prevent the nerve sliding back irrespective of the  new placement of the nerve sub fascial or sub muscular. The skin is closed in one layer which includes the subcutaneous tissue. Because the incision extends into the lower half of the upper arm the tourniquet is applied a little higher and most surgeons prefer general anaesthesia for the procedure.
  6. Below are reproduced photographs of a patient who had both, the ulnar and the medial nerve pathology following a supra-chondylar fracture, corrected and fixed with implants. Pictures provided by Rajendra Nehete, plastic and hand surgeon, Nasik, Maharashtra, India.

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The following pictures are of Ulnar nerve transposition courtesy Mukund Thatte, plastic and hand surgeon, Mumbai involving an abnormal insertion of the triceps, compression by the Struthers ligament  as well as compression in the cubital tunnel.

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  1. From here on the ulnar nerve courses over the interosseous membrane till it approaches the wrist where it lies superficial to the flexor retinaculum and then divides into two branches superficial and the deep The superficial branch supplies the palmaris brevis a cutaneous muscle and supplies sensations to the whole of the little finger and the ulnar side of the ring finger as well as the hypo-thenar area. The deep branch of the ulnar nerve is more important because it supplies all the interosseous muscles (both palmar and dorsal) the adductor of the thumb and the ulnar lumbricals. A structure called the piso-hamate ligament crosses superficial to the passage of the ulnar nerve over the flexor retinaculum and encloses it in a tunnel named after Guyon who described it in 1861. The ulnar nerve is vulnerable to compression in this area by sheer lack of space (sometimes brought on by inflammation in the surrounding area and may be temporary) or by space occupying lesions such as a ganglion, post traumatic residue of a fracture of the hook of the hamate or its non-union, non-specific inflammatory conditions or a post traumatic aneurism of a branch of the ulnar artery which lies medial to the nerve on a deeper plane and is separated from the nerve by a fascial structure. Repeated trauma to the hypothenar area adjoining the wrist or sustained pressure to the area by a handle of a two-wheeler is known to cause a compressive neuropathy in this area. This condition is far less common than the carpal tunnel syndrome but it can lead to clumsiness of actions involving the adductor muscle wasting of the hypothenar area and may result in clawing of the ulnar fingers with extension at the M.P. joints and flexion of the interphalangeal joints  As in other compressive neuropathies the condition begins with altered sensations (in the hypothenar area in this instance) tingling and numbness and a deep ache. The differentiating feature being intact sensation on the dorsum, since the dorsal sensory branch is given proximal to the wrist in the lower part of the forearm and is not compressed.

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  1. In mild early cases a splint in a neutral position and rest and reducing pressure on the hypothenar area might help the patient. In more severe cases where pain is exacerbated by local pressure or by forced radial deviation and muscles are affected surgery will need to be undertaken after an x ray preferably a C.T scan to look for undiagnosed fractures of the hamate particularly in the region of its hook. A M.R.I. can also help to diagnose soft tissue lesions that might be causing pressure on the Guyon’s canal. An electro diagnostic test such as a sensory nerve action potential (SNAP) of the ulnar nerve will help confirm compression. Such diagnostic precautions are essential because the condition is uncommon its muscular manifestations are not always apparent and a post traumatic arthritic pathology in the region might be all that the patient has and can be treated without surgery.
  2. The incision in the palm used to release the median nerve from the carpal tunnel can also be used to release the ulnar nerve from the Guyon’s canal except that it might have to be extended by about a centimetre proximally towards the wrist and also across it parallel to its transverse crease (please see diagram above). The soft tissues are incised and retracted and the free border of the hypothenar muscles is identified. The hook of the hamate is palpated by the tip of the index finger and the Guyon’s canal is located. It is in the region of the fascia covering the proximal free border of the hypothenar muscles that the deep branch of the ulnar nerve makes its appearance after going around the hook of the hamate and travels across the palm to supply the adductor of the thumb and is usually accompanied by a leash of blood vessels. The fascia in the proximal part of the hypothenar muscles needs to be carefully tenotomised to expose the deep branch fully and is then traced proximally to its origin from the ulnar nerve which is then released from the confines of the Guyon’s canal by de-roofing it with a scissors introduced in the canal. A carefully introduced small right angled retractor when lifted will demonstrate if the canal is fully opened or not and will also determine the presence of any tightness of the ante brachial fascia. The release of this fascia if required as well as the release of the canal is helped greatly by the transverse extension of the vertical incision. All operative steps are undertaken under vision with magnification and the fact that the ulnar artery lies medial and deeper to the nerve must be borne in mind. Also if the cause of the compression happens to be a small post traumatic loose piece of the Hamate bone (sequestrum) or an abnormal post traumatic dilatation of a blood vessel (an aneurism) those conditions must be dealt with. The wound is closed after haemostasis. The nature of anaesthesia for this procedure is no different from the ones used for the release of the carpal tunnel syndrome which have been narrated in the previous chapter. Following photographs have been supplied courtesy Rajendra Nehete, hand and plastic surgeon, Nashik, Maharashtra, India. The incision employed here is similar to the one described in the text above.

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The following pictures are kindly provided by Mukund Thatte, hand and plastic surgeon, Mumbai.

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November 15, 2017

66. Compression neuropathy of the median nerve in the upper arm

Filed under: Chapter 66,Uncategorized — ravinthatte @ 4:45 am

66. Compression neuropathy of the median nerve in the upper arm

The contribution of Mukund Thatte, hand surgeon, in editing and supplying information and providing illustrations, is acknowledged. The illustrations of dissected specimens were entirely the work of Maksud Devale (Professor) Chirag Bhansali and Gaurav Kadakia senior residents in the department of plastic surgery at the Lokmanya Tilak Municipal General Hospital and medical college Mumbai India. Professor Natarajan head of the anatomy department kindly consented to undertake the dissections under my supervision (Ravin Thatte).

  1. The most frequent compression neuropathy in the arm is that of the median nerve as it courses under the flexor retinaculum of the wrist which encloses a space called the carpal tunnel underneath the carpal ligament. This forms the central third of the retinaculum and the neuropathy is called the ‘carpal tunnel syndrome’ (CTS). The condition was briefly touched upon in the previous chapter which dealt with the general principles of compression neuropathies. CTS will be covered in detail at the end of this chapter but the median nerve can also be compressed, though less frequently, in the lower arm and in the fore arm and those conditions are narrated here first, including the anatomy of the nerve as it courses below and branches into the palm.
  2. The median nerve is a mixed nerve borrowing its sensory fascicles from the lateral cord of the brachial plexus and the motor fibres from its medial cord except for the pronator teres which might get some fibres from the lateral cord.

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  1. About three inches above the elbow in a normal adult the nerve lies between the brachial artery on the lateral side and the brachialis and the medial inter-muscular septum on its medial side.

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  1. As it courses below, in very rare case, it might encounter a ligamentous structure extending between an accessory and abnormal origin of the pronator teres muscle on the humerus to a spur on the same bone under which the nerve must pass unlike the brachial artery which lies superficial to this structure. The ligament is named after Struther also called an arcade.

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  1. The main symptom of these entrapments is pain which gets exaggerated when resistance is applied to pronation. A solitary entrapment by the Struthers ligament is not easy to diagnose though evidence of a humeral spur on a plain radiograph or a C.T scan can help. Should such a diagnosis be clinched then surgery involves a simple release of the band.

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  1. Below, the median nerve is related to the two origins of the pronator teres muscle between which it passes. (The humeral and the ulnar head). This is also the area which is covered by a tough structure called the bicipital aponeurosis which is a modification of the deep fascia of the area shown in photographs of a dissected forearm in an earlier paragraph.
  2. Rarely the nerve might pass deep to both heads of the pronator teres or an abnormal dense band might be present between the two heads of the pronator teres muscle leading to impingement of the nerve. This condition is particularly common in individuals whose job involves repeated forceful actions of flexion and pronation. The tough nature of the bicipital aponeurosis perhaps contributes to the condition. This condition is called the pronator teres syndrome. The main symptom of this condition is pain, exaggerated when pressure is applied to the free border of the pronator in the upper third of the forearm in full supination or when flexion at the elbow or pronation of the forearm is resisted (The provocation test). See illustration above.
  3. The condition may result in altered sensibility over the thenar eminence and the index as well as the middle finger. The diagnosis is mainly clinical.

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  1. To treat the condition the exposure of the area is done by an incision in front of the elbow in the form of a lazy S and as the first step the bicipital aponeurosis is incised and released and retracted to expose the two heads of the pronator teres. They in turn are retracted to expose the median nerve and the obstruction to or compression of the nerve by the two heads of the pronator becomes evident following which the nerve is released from the pincer action of the two heads of the muscle. The obstruction might be in the form of a fibrous band or just thickened fascia. Occasionally a bulky part of the muscle might have to be myotomised. The incised bicipital aponeurosis is not closed and the resulting defect is left open. This allows the space around the pronator to remain capacious and helps to resolve the pathology (see illustrations above). The incision used for the procedure can also be used to explore the area above the elbow to feel for and then release the Struther’s ligament if present.
  2. As the median nerve courses down from this area, it for all practical purposes is a dual conduit because the fascicles of the anterior interosseous nerve (A.I.N.) are lying separately within the same epineurial The A.I.N branches from the median nerve here from its posterior surface to travel deep to it over the interosseous membrane. The anterior interosseous nerve may on rare occasions get compressed here by the overarching fibrous arch of origin of the flexor digitorum sublimis. The A.I.N. specifically supplies the flexor digitorum profundus of the index finger and sometimes the flexor digitorum profundus of the middle finger but always supplies the flexor pollicis longus and the pronator quadratus. Its sensory distribution is restricted to carpo-metacarpal joints and the radio ulnar joint. The compression of only the A.I.N. therefore results in weakness in the flexion of the interphalangeal joint of the thumb and the weakness of the long flexor of the index specifically without any loss of sensations over the thenar eminence. This is usually called the anterior interosseous syndrome which causes pain locally and which may radiate along the course of the nerve. The sensory supply to skin over the thenar eminence comes via a branch of the median nerve about 5 cms proximal to the flexor retinaculum of the wrist and the presence of altered sensations over the thenar eminence together with weakness of the long flexor of the index and the thumb usually indicates a compression of the main trunk of the median nerve before the exit of the A.I.N. The treatment of the A.I.N. syndrome involves employing an incision similar to that described for the pronator syndrome but might have to be extended a little lower so that the tendinous fibrous arch of the sublimis can be divided under vision. In reality the release of the ligament of Struthers if present, the release of the median nerve in the pronator syndrome and the division of the fibrous arch of the sublimis in the A.I.N. syndrome may be accomplished in a single surgical procedure because an accurate differential diagnosis of each separately is not always possible.

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  1. This brings us to the course of the median nerve under the flexor retinaculum of the wrist. The retinaculum is divided into three parts the central third of which is the toughest and is spread across the carpal bones and is called the carpal ligament. The proximal part is a continuation of the ante brachial fascia and the distal third continues as the somewhat thick palmar fascia. The retinaculum in the distal third is attached to the borders of the thenar and hypothenar muscles. The description of the density of these structures (ante brachial fascia and the palmar fascia) is important because they too may contribute to the compression of the nerve and a mere release of the retinaculum and the carpal ligament may not suffice. This additional release is usually achieved after inspection by the naked eye following the release of the retinaculum. On either side of the retinaculum lie the long flexors of the wrist at their insertions. The palmaris longus tendon inserts in the proximal free border of the flexor retinaculum and then spreads over it as a fibrous insertion. The median nerve accompanied by the median artery is the most superficial structure when the retinaculum is opened. The flexor superficialis and profundus tendons to the four fingers lie below the nerve in that order and the flexor pollicis longus lies on the radial side of these tendons. Because the median nerve is the most superficial structure here, in extremely rare cases it may be horrendously mistaken for the palmaris longus tendon at the time of its blind harvest as a tendon graft. The median nerve under the retinaculum carries the motor fascicles for supplying the small muscles of the thumb namely the abductor pollicis brevis, the opponens pollicis and the flexor policis brevis (the superficial head). These fascicles emerge as the recurrent branch of the median nerve which most frequently emerges beyond the distal margin of the flexor retinaculum. The emergence of this branch is however subject to variations in one of which it pierces the retinaculum while underneath it. That as well as other variations are included in the figures below.  It is best therefore when planning the incision to  place it about a centimetre on the ulnar side of the Thenar crease (see illustrations below).

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  1. The principle features of C.T.S. are altered sensibility on the radial side of the palm and radial side three and a half fingers sometimes leading to anaesthesia, weakness of the thenar muscles leading to clumsiness in actions performed by those muscles for example abduction or opposition by the thumb accompanied by pain particularly at night. In fact nocturnal pain on the radial side of the hand might be the only symptom that might bring the patient to the clinician when the other clinical features have not manifested. C.T.S. of some duration will result in wasting of the thenar muscles. The diagnosis is clinical in a vast majority of cases by way of tests shown in the figures below. If a psychosomatic element is suspected or in cases of suspected malingering electro diagnostic tests may be useful. Such tests might also be undertaken to judge the results of surgery if the patient complains of lack of relief following the surgical procedure. Many units however use electro-diagnostic methods as a routine.

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Photographs courtesy Bipin Ghanghurde

  1. Many or most patients consult surgeons after some form of medication has been tried for C.T.S. Anti-inflammatory drugs are the most frequently used. Many patients try massaging, some try some form of alternative medicine and others take a variety of exercises before seeking a surgical opinion. In the surgeon’s hand two forms of conservative treatments are available, injection of corticosteroids under the flexor retinaculum or splinting. Of these two, splinting in the position of function with the wrist extended in 30degrees extension has been objected to because of the increase in pressure it would cause within the carpal compartment. The neutral position is therefore preferred and that too in the form of night splints. Among the corticosteroids dexamethasone is preferred because it causes the least injury if inadvertently injected into the nerve. Of those who undergo surgery there are those who find the condition unbearable even after some form of conservative treatment or those that are convinced by the surgeon of the effectiveness of the surgical treatment soon after the first surgical consultation as opposed to any form of expectant conservative treatment. Surgeons may occasionally take recourse to conservative treatment in the form of injections of corticosteroids to give temporary relief and suit the patient’s convenience to postpone surgery for some time.
  2. Surgical treatment consists of laying open the flexor retinaculum in its entirety (including the distal palmar fascia and the proximal ante brachial fascia if required) to relieve pressure over the nerve and its emerging branches and to leave those layers open. Only the skin and subcutaneous tissue is closed at the end of surgery. This briefly describes the open approach. An endoscopic approach has been described in recent years with “key hole” incisions and special instruments have been devised for this purpose. Only a minority of surgeons practice this method probably because the incisions employed in the open approach are not very long and the hospital stay in either method is no different, most patients being treated on a day care basis. The cost of endoscopic instruments, the learning curve to master the technique and no evidence of the technique’s superiority over the open approach might be the other reasons why the method has not gained adequate popularity.
  3. The incisions employed to treat C.T.S are many but they mainly fall in two parts, an incision employed in the palm parallel to the main thenar crease on its ulnar side (Please see figure above para12) and another incision in the transverse wrist crease. If they should be joined in the form of a lazy S is a matter of choice. As far as possible a vertical incision across the wrist crease should be avoided because it transgresses the horizontal arrangement of the elastic fibres within that crease and can lead to a bothersome and conspicuous hypertrophic scar. Surgery is performed under a tourniquet on the arm except in very obese individuals where the tourniquet is applied on the forearm. Most surgeons prefer not to employ formal general anaesthesia with an intratracheal intubation but a few surgeons opt for a laryngeal mask and some form of anaesthesia. A vast majority employ a combination of deep infiltration of a local anaesthetic agent after sedation because the tourniquet time is not long. The tourniquet is raised after the infiltration and the patient is prepared and draped. Because some specialisation is required to execute a brachial or an axillary block that practise is also not commonly employed. Intravenous analgesia with the tourniquet raised ahead of the injection of the analgesic agent is also effective but is employed only in some units.
  4. The surgery is begun in the palm. After the skin is incised the palmar fat is visualised which is cut and retracted and the distal part of the flexor aponeurosis is identified. A blunt dissection is employed to identify structures entering the palm from underneath the retinaculum particularly the motor branch of the median nerve to the thenar muscles if it is following its most common course. If not the focus shifts to the main trunk of the median nerve emerging from underneath the retinaculum. A scissor can then be introduced under the retinaculum as ulnar-wards as possible to the median nerve and is opened to create a space in the carpal tunnel. The scissors are then employed to undermine the skin superficial to the retinaculum up to the wrist crease and a retractor is placed in the subcutaneous space and is lifted to expose the flexor retinaculum in almost its entirety and brought under vision. At this time the scissors can now be employed to cut the retinaculum as well as its carpal ligamentous portion up to the proximal wrist crease. In the past it was customary to trim any abnormal swelling in the sheath of the flexors under the retinaculum. This practise now appears to be on the wane unless the swelling of the sheath is abnormal and occupies the whole of the space under the retinaculum in which case the bulky synovial sheath is excised and biopsied. Only in those cases where the ante-brachial fascia appears to be tight on visual inspection or palpation that a transverse incision may be employed in the wrist crease to expose it and is then carefully incised with a 15 number blade under vision to release the last remnants of the compressive pathology. Since the dissection was begun in the palm any tightness of the palmar fascia will have been dealt with when the retinaculum was identified. All visible bleeders are cauterised and the wounds are closed, skin and subcutaneous tissue together, with interrupted stitches. A bulky soft tissue dressing is given preferably with a splint to immobilise the wrist for a week when the stitches are removed and gradual active and passive physiotherapy follows. Usually the patient is ready to do all normal activities within two weeks. Intra operative photographs with a small incision which allows all the steps mentioned in the above paragraph and showing some specific anatomic structures not mentioned in the above paragraph are reproduced below. Photographs courtesy Mukund Thatte.

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  1. The results following surgery of C.T.S. are satisfactory in a vast majority of cases. If the diagnosis is correct and the release of the carpal tunnel is complete. The bothersome altered sensations as well as pain disappear even before the stitches are removed. Wasting of thenar muscles is another matter. If they can be brought back to their original size will depend upon the efforts that the patient undertakes to retrain them as well as the amount of wasting that has already occurred. There appears to be some disagreement on the subject as to whether the power really comes back to the original following surgery. Irrespective whether the size and strength are regained or not the clumsiness that the patient experienced in certain actions pre-operatively almost always disappears. Conditions such as obesity or diabetes which predispose to many a condition including C.T.S. have been narrated in the previous chapter. They will have a certain bearing on how the patient will do in the long run.

Addendum:

Dr. Beng Hai from Singapore, who was a faculty at the recent meeting of the Indian Society for the Surgery of the Hand, together with the Singapore society 2017, gave two examples of how a severely fibrosed median nerve after the release of the carpal tunnel syndrome can be neurotomised parallel to the fascicles in order to restore its function (photograph to the left). He also pointed out that occasionally a space occupying lesion within the carpal tunnel can produce features of a carpal tunnel syndrome and can be usually diagnosed by an ultrasound examination (photograph to the right).

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September 7, 2017

65. Compressive neuropathy of the peripheral nerves in the upper limb General information

Filed under: Chapter 65,Uncategorized — ravinthatte @ 6:26 am

Compressive neuropathy of the peripheral nerves in the upper limb: General information

The speciality of the surgery of the hand (also called hand surgery) is now over 50 years old in India but older in the western part of the world. Over the years both orthopaedic as well as plastic surgeons have first migrated towards this speciality and then taken it up as a full-time occupation. A general surgeon taking up this speciality is more an exception than a rule. This chapter has therefore been vetted by Mukund Thatte a plastic surgeon and a leading practitioner of surgery on the brachial plexus and peripheral nerves as well as two orthopaedic surgeons Sudhir Warrier and Pankaj Ahire both of who restrict their practice entirely to surgery of the hand. All three have their practice in Mumbai India.

This chapter focuses only on peripheral neuropathies in the arm and does not include conditions which involve the brachial plexus or conditions such as the thoracic outlet syndrome.

  1. All activity within living tissues can be described as electro chemical in nature and this in recent times has been collectively called physics. Slide1 Erwin Schrödinger’s work on the genetic makeup of living beings in his seminal work published as “What is Life” has shown that all living activity can be reduced and explained as principles of physics. Nowhere else in the body is this electro-chemical activity more evident than in the functioning of the nervous system. The nervous system is not only aware of the conditions that prevail within the body and is able to react to the changes that occur with appropriate responses but is also aware of the organism’s environment and allows suitable actions to be taken to safeguard the interests of the organism.
  2. The agents for the perception and execution of these actions are the nerves made up of axons the longer of the two cytoplasmic projections from the neuron or the nerve cell. The shorter of the two projections the dendrites, in a vast majority, serve as connections between adjacent neurons.
  3. The peripheral nerves in the limbs are the longest nerves in the body which traverse long distances through anatomical compartments and tunnels and are therefore prone to pressure and or compression at various sites. Because the hand as an organ is far more skilful than the foot and is vital to a myriad of daily activities, compressions of the nerves in the arm leading to clinical problems appear to be more frequent than those in the lower leg. As noted in the preamble to this chapter this statement excludes the conditions which arise because of problems related to the vertebral column in the inferior extremity.
  4. The basic unit of the nerve is the axon a long protoplasmic extension from the neuron and is called axoplasma. A few axons make a fascicle and several fascicles make a nerve. The axons are covered by a connective tissue layer called endoneurium, fascicles are sheathed by connective tissue called the perineurium and the nerve in turn by the epineurium which is quite thick sometimes up to forty percent of the cross section of the nerve. The epineurium has a mesentery called the meso-neurium through which blood vessels enter or leave to fulfil the nerve’s metabolic requirements.
  5. The axons can be large in diameter or small. They can also be myelinated or non-myelinated. The non-myelinated axons are fewer in numbers. Myelination is an attempt by nature through evolution to ensure faster conduction of the electrical impulse without spillage. The myelin coating of the axon is laid down by the Schwann cells. Because the distance that the electrical impulse must travel is long the axons have nodes first described by Ranvier (nodes of Ranvier). These nodes act as substations like in man-made electrical grids where conduction is optimised by a saltatory process. (Saltatory as in leaping). These nodes in fact are relay stations. The myelin sheath is interrupted at each node. As can be seen the non-myelinated fibres are inferior in their conducting efficiency. Though they are surrounded by Schwann cells they do not provide them with a myelin sheath.

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  1. The axon is enclosed within a layer of endoneurium a layer not previously mentioned in the paragraph above. The endoneurim itself is extremely thin and is made of connective tissue of mesodermal origin and encloses a network of capillaries more profuse than in the sub-perineurial layer and the capillaries are broader in diameter than the capillaries elsewhere in the nerve probably on account of being the terminal vessels actually nourishing the nerve tissue. What is more the nerve mimics the brain by creating a blood nerve barrier here in which together with the subperineural blood vessels, a privileged environment is created which resists deleterious effects of metabolic changes that occur on the outside. When this limit is crossed by an external force as happens in a compressive neuropathy an ‘internal compartment syndrome’ results. Because the nerve itself has no lymphatic drainage the resultant oedema leads to accumulation of proteins and the loss of privilege incites an inflammatory response to antigens from which the axon had been protected earlier. Lymphocytes and macrophages follow into this zone of inflammation. The myelin sheath gets destroyed first in patches then over a length followed by formation of scar. The conductivity of the nerve suffers and if the condition is not treated till the effects of the compression are reversible the area of supply of a given nerve suffers consequences such as anaesthesia or loss of function of muscles. The following figures are schematic and do not purport to be real cross sections of a nerve but are drawn to understand how the structure of a nerve is organised. For example, the myelin sheath is pearly white in colour but shown here in black because it is very difficult to show a white pearly appearance in a diagram. The same applies to all the sheaths.

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  1. An acute compression neuropathy can occur following an improper use of a tourniquet on the arm ironically when surgery is being performed for treating conditions in the hand. The incidence of this kind of ‘palsy’ is much lower now because of the introduction of pneumatic tourniquets (some of them with alarms indicating the duration of application). Mercifully most patients recover completely. The available texts have paid little attention to the exact nature of the pathology that follows in the nerve in cases of a tourniquet ‘palsy’ and if any degree of rapid demyelination occurs in the affected nerves.
  2. The blood supply of the nerves develops as the nerves grow in the limb buds and it is this neuro-ectodermal tissue that orchestrates the development of the capillary network in its vicinity which later develops into vessels. The rationale of a neuro cutaneous flap is this synchronous development. The median nerve in the forearm for example is supplied by the median artery which overlies it and also by the branches of the anterior interosseous artery in the same fashion that the radial artery supplies branches to the radial artery forearm flap. The ulnar nerve near the elbow is supplied specifically by the ulnar collateral arteries which draw their blood supply from the brachial artery and have been used for a free ulnar nerve transfer. The blood supply to the nerve as can be seen is either axial or segmental.

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  1. It has to be borne in mind that the axons are open live conduits and their axoplasmic flow is bidirectional. This means that the products of abnormal metabolism have a free play in either direction. Therefore, a compression pathology in the proximal part of a nerve may have consequences in a distal part of the same nerve when it lies in a vulnerable compressible area. For example, a patient with a thoracic outlet syndrome may later develop a carpal tunnel syndrome. This is called somewhat harshly as a ‘double crush’. This can happen the other way around as well and is called the reverse double crush in which a distal lesion can precipitate a proximal pathology. Diabetes obesity, hypothyroidism, abuse of alcohol and tobacco the usual culprits in many diseases have also been statistically proved to have a role as predisposing factors in the development of compression neuropathy. A hereditary condition in which trivial trauma precipitates demyelination in nerves leading to symptoms both motor and sensory might sometimes be confused with a compression neuropathy. These cases show a rapid onset and total recovery they may be recurrent and occur at various sites. Clinicians must have this condition at the back of their minds before arriving at a diagnosis of compression neuropathy which has a steady progressive course.
  2. Most living tissues have an optimal ability to stretch and the nerve is no exception. The nerve in some measure resembles a woven rope as fascicles traverse distally and get straightened if stretched. The mesoneurium also has a certain play when it gets stretched. Nature therefore protects the nerve while the body pursues normal activities but is vulnerable when a certain limit is crossed particularly when the stretching action is performed repeatedly. Modern life creates many situations which put the body and particularly the upper arm through repetitive abnormal movements in certain occupations. The significance of this is not so much in the causation of the compression pathology but in the effects that this stretching produces when the nerve is already beginning to get compressed because the compressed nerve tends to lose its elasticity and therefore suffers repeated trauma. Ironically the practice of yog now popular all over the world to ward off the ill effects of modern living if practiced with excessive and unnecessary vigour can aggravate many an existing condition in the limbs as well as a compressive neuropathy. These facts are important when taking the history of a patient with compression neuropathy.
  3. The preceding paragraphs form a background with which a clinician must be familiar so as to be able to diagnose a case of compression neuropathy. What follows is taking down a detailed history which includes the additional information that the patient gives on his own, physical examination and electro diagnosis when there is a doubt about the diagnosis.
  4. The patient’s complaints more often than not are sensory in nature for example tingling and numbness. It might be revealed on direct questioning that the sensations that the hand generates are not quite what they should be (paresthesia). Aching pain and fatigue are caused by muscular weakness but the ache that the patient complains of might in fact be severe numbness. The tingling might be getting aggravated by activity and there are patients who are miserable enough with their symptoms to lose their confidence for doing their daily activities. Insomnia is not unknown. A patient might complain that a particular action is difficult to perform for example turning the key for opening a lock or that a particular area of the palm is dry and rough. It might also have been noticed that the affected hand has become weak. There might be symptoms of intolerance to cold or hot objects. Generally speaking the symptoms of a compressive neuropathy vary greatly and only the common ones have been narrated here.
  5. Notwithstanding the variety of tests that have been described to test for loss or altered sensations the results of these tests are not always reliable or conclusive on account of their subjective nature. If the condition is unilateral it helps a great deal to make a comparison and then arrive at a firmer conclusion. Light touch can be measured by moving cotton across the affected and the contralateral normal part and then measured in ten grades (one to ten) and compared. The capacity to feel a vibratory impulse can be tested either by a tuning fork or by a specially designed instrument with multiple frequencies because there is a theory that high frequencies are lost the earliest in compression neuropathies. Cutaneous pressure thresh holds can be tested by mono filaments of increasing diameters till they bend and two – point discrimination formerly tested with a paper clip is now measured by instruments which are more sophisticated. However, as things stand two-point discrimination is one of the last sensory modalities to be lost in compressive neuropathy and is a poor diagnostic tool to diagnose the condition early.

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  1. The motor impairment in the palm is somewhat easier to diagnose though the exact amount of loss of power in the small muscles of the hand cannot be graded as is done in the larger muscles in other parts of the body. Wasting of muscles in the palm is also easier to diagnose particularly when compared to the opposite side but here too the clinician must take into account which of the two hands is dominant. Many a times the non-dominant hands have leaner palms. While the hand is being examined it is worthwhile to observe palmer sweating. Though there is very little that we know of the autonomic component of the nerves in the hand the region supplied by the affected nerve is more likely to be dry.
  2. Perhaps the more reliable methods to diagnose nerve entrapment are by the use of percussion or pressure on the known course of the nerve or to cause provocation by bending the joint to an extreme position for a minute across which the nerve passes in a canal. The manoeuvre causes reduction in the space of the canal in which the nerve lies and produces exaggeration of the symptoms that the patient is suffering from. In the case of the median nerve pressure can be applied over the middle of the pronator teres resulting in pain, percussion can be done proximal to the carpal tunnel leading to unpleasant tingling along the nerve and provocation can be induced by extending or flexing the wrist through its maximum range with the forearm in the supine position for a minute which causes the symptoms to increase several folds. These tests will be given in detail with figures in sections on individual nerves later in this blog.
  3. The nature of the impulse in the nerve being electrical and the result of that impulse on the muscle also being electrical the rational thing has been to subject cases of compressive or other neuropathies to electro diagnosis. This is a speciality in itself and only the bare minimum information is provided here. The electro diagnosis is divided in two parts, electro- myography and nerve conduction studies. In myography a sharp needle is inserted in a muscle and its electrical activity is noted on a graph. A muscle which has been denervated for a long time and is wasted and in which the muscle fibres are replaced with fibrous and collagenous tissue is silent and will not transmit any impulse across the needle. A muscle which has lost its nerve supply completely approximately for a period of more than two weeks will show fibrillations which denote an autonomous electrical activity in the muscle. A normal muscle upon insertion of the needle responds with a brief burst of electrical activity. When the patient is asked to contract the muscle with the needle in place a normal muscle recruits a large number of muscle fibres leading to what is known as interference pattern because of overlapping. In a muscle recovering after a successful repair of a nerve serial myographies will show a greater recruitment of muscle fibres over a certain duration.
  4. Nerve conduction studies are performed by placing two electrodes along a nerve one of which is the stimulating electrode and the other is the receiving electrode. The conduction can be studied in either direction. Unlike the motor axons which are bigger the sensory axons are smaller the amplitude of the waves generated in them is also smaller and the electrical activity is expressed in microvolts as compared to in the motor axons which are designated in milli-volts. It is customary to measure the speed with which the impulse passes in milliseconds. Because the quantities involved are very small the investigation can be marred by room temperature the temperature of the surface on which the electrodes are placed or by technical problems. Therefore, a comparison with values on the normal side is far more important in nerve conduction studies. A difference of about fifty percent between the two sides is considered diagnostic of a pathological entrapment of the nerve.

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  1. It is a moot point as to if in clinical practice treatment should or can be undertaken without recourse to electro diagnostic methods in cases of compressive neuropathy or if these methods are used only when the diagnosis is doubtful and in those cases where the patient needs to be convinced of the diagnosis.

 

 

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