Short Notes in Plastic Surgery

January 20, 2017

Chapter 60. Understanding flaps based on Perforators (Vasculosomes)

Filed under: Chapter 60,Uncategorized — ravinthatte @ 5:47 am

Chapter 60. Understanding flaps based on Perforators (Vasculosomes)
(Addendum to Chapter 59)

This chapter was invited from Adhish Basu, Kolkata, whose work on perforator flaps won the Kilner Essay Award (2016) of the Association of Plastic Surgeons of India. He presents a slightly different view of perforator flaps as compared to the previous chapter.

There has been a long-standing confusion towards naming traditional peninsular-design skin flaps (like the groin flap) as perforator flaps. While harvesting these flaps, the operator takes a leap of faith as the perforators that obviously provide the flap with nourishment essential for it’s survival are not visible! Although not visible, the perforators are present and therefore the flap should be called a “perforator flap”. Unfortunately, flap nomenclature has traditionally been based on flap dissection techniques rather than on their vascular basis. When Fu-Chan Wei et al described their ‘free-style perforator flap from the thigh, the dissection of perforators through the muscle was a requirement to call it a perforator flap.[1] It was actually Ye-Guang Song and co-workers who were the first to describe a perforator flap from the thigh in 1984, years before Isao Koshima described the perforator flaps from the abdomen in 1989.[2][3] The reason why Koshima is often quoted as the first one to describe perforator flaps is because of his description of intramuscular dissection of the pedicle over a long distance.[3] The free-style concept was actually first described by Sipra Asko-Seljavaara in 1983 who proposed an exploratory skin incision for dissection of the perforator around the point where it perforates the fascia.[4] Hence all isolated perforator flaps are actually free-style in concept. The question of whether the tissue characteristics of the donor and recipient match, needs to be addressed by any flap that is harvested, and not necessarily the flap has to be one that has its perforators skeletonized![5]

The vasculosome theory provides a physiological basis for harvesting perforator flaps.[6] (Figure 1) Based on the principles of the vasculosome theory the flaps based on perforator vessels may be classified into three broad categories viz. “isolated” perforator (IP) flaps, “clustered” perforator (CP) flaps and combined perforator flaps.[5] (Figures 2 and 3).

vasculosome-theory-basu-flap-classification-fig-1

vasculosome-theory-basu-flap-classification-fig-2

vasculosome-theory-basu-flap-classification-fig-3

When a single vasculosome is harvested based on dissected and isolated perforator vessels the flap is termed an Isolated perforator flap. (Figure 2) On the other hand when one or more vasculosomes are harvested based on one or more perforators which have neither been dissected nor been isolated, the flap is termed a clustered perforator flap. (Figure 2) Both isolated and clustered perforator flaps have subtypes. While the isolated perforator flaps may be subdivided based on the length of pedicle dissected into long and short types; the clustered perforator flaps may be classified into peninsular (Latin paene = almost and insula = island) and island subtypes. An example of the peninsular clustered perforator flap is the traditional groin flap; whereas examples of the island clustered perforator flap are Behan’s keystone design island flap and the radial forearm flap (where multiple forearm vasculosomes are supplied by a long source vessel, the radial artery). The pectoralis major musculocutaneous flap when harvested as a true island flap is also an example of an island clustered perforator flap, the muscle mass being incidentally included in the flap.

If more than one vasculosome is individually harvested on isolated perforators but are eventually joined with a single source vessel, these flaps are termed chimeric perforator flaps. (Figure 3) When a flap has more than one vasculosome included with two separate feeding perforators, the flap is termed a conjoined perforator flap (previously termed Siamese flaps). (figure 3) The latter requires two sets of feeder vessels for complete survival of the flap. Peninsular clustered perforator flaps which require arterial supercharging or turbocharging for complete survival, are basically conjoined flaps.[5]

References

  1. Wei FC, Mardini S. Free-style free flaps. Plast Reconstr Surg 2004;114(4):910–916
  2. Song YG, Chen GZ, Song YL. The free thigh flap: a new free flap concept based on the septocutaneous artery. Br J Plast Surg. 1984 Apr;37(2):149-59.
  3. Koshima I, Soeda S. Inferior epigastric artery skin flaps without rectus abdominis muscle. Br J Plast Surg 1989;42(6):645–648
  4. Asko-Seljavaara S. Free style free flaps. In: Programs and Abstracts of the Seventh Congress of the International Society of Reconstructive Microsurgery. New York, NY; 1983
  5. Basu A. Classification of flaps and application of the concept of vascular territories. In Textbook of plastic, reconstructive and aesthetic surgery, Edition: 1, Chapter: 5, Publisher: Thieme, Editors: Karoon Agrawal, 2016, pp.93 – 120
  6. Basu A. The vasculosome theory. Plast Reconstr Surg 2015; 135(2):449e–451e

November 14, 2016

59. Understanding flaps based on Perforators

Filed under: Chapter 59,Uncategorized — ravinthatte @ 9:04 am

This small chapter is included in this blog to acquaint the readers with nomenclature of  perforator based flaps. To that end the compiler of this blog wrote to Sameer Kumta and Leena Jain two leading microvascular surgeons in private practice in Mumbai India and the following communication was sent to them.

The human circulatory system being centrifugal and because the integument is the body’s outermost layer the vessels that supply it need perforce to pierce fascial envelopes to supply and drain it. The word perforator was majorly used by Ian Taylor the well known plastic surgeon from Australia whose voluminous work was published in the late eighties and nineties, mainly in the British Journal of Plastic Surgery and involved a very large number of cadaveric dissections. These dissections involved the vascular network surrounding the neural network and it was he who conceptualised the idea of an angiosome to define territories of vascular supply based on independent perforator vessels.

The word ‘envelopes’ at the beginning of the preceding paragraph is used in the plural because fascia is present in multiple planes in the body. For example, it envelopes the arteries themselves and is also present as an inter-muscular septum as well as an independent entity which encases the muscle (perimyceum). The fascia is also present in the subcutaneous plane through which the vessels pass to ultimately supply the skin. The question that needs to be clarified is at what level does a vessel come to be called as a perforator. For example the historic Sushruta flap or the forehead flap is now known to be supplied by the supra-trochlear vessel which penetrates the local deep fascia after traversing a bony gutter in the orbit to supply the skin over a large area of the forehead. Could this flap then be called a perforator flap because the concerned vessel pierces the local deep fascia? A similar question can be posed about the well-known ‘groin’ flap based on the superficial external iliac artery. This vessel is a branch of the femoral artery and is termed as a direct cutaneous artery in the existing classification though it has pierced  the femoral sheath which in fact is a condensed form  of the regional deep fascia and what is more a flap is now based on one of its very tiny branches which passes through the subcutaneous tissue to supply a sizable area of skin and can be transferred by way of a micro-vascular transfer. Is this flap a perforator flap? The reply of doctors Kumta and Jain to this communication by the compiler of these short notes is reproduced below. The relevant diagrams were drawn jointly by the compiler and the two expert contributors.

Introduction

Koshima and Soeda in 1989 first described perforator flaps to differentiate an adipocutaneous flap from the conventional fasciocutaneous flaps to highlight the fact that the supra and subfascial plexus were not essential for a flap’s survival. With over 400 perforators more than 0.5 mm in diameter being available across the body, any part of the body can be thus considered as a potential perforator flap donor site, in line with the principle of a free-style perforator flap. This march from conventional flaps to ‘free style’ flap has been revolutionary due to the multiplicity of donor sites that can be harvested in various parts of the body.

To begin with the definition; a perforator flap is one that receives its blood supply from a fascia-perforating vessel whether directly perforating or indirectly perforating it after traversing the muscle or the intermuscular septum. To understand the basic course of a perforator, Werner Spalteholz (1893) has classified them into a direct or a pure artery that directly enters the skin (direct cutaneous perforatorDCp) and an indirect or impure artery that penetrates the muscle / septum and then supplies the skin (musculocutaneous perforator –  MCp and septocutaneous perforatorSCp). This course in practical terms determines  whether or not intramuscular dissection would be required while harvesting a particular perforator flap.

Nomenclature

Newer perforator flaps continue to be described; however there is no uniform anatomical nomenclature of perforator flaps.  The basic requirements to standardise a nomenclature are:

  1. Should be simple to understand and reproducible by any micro-surgeon
  2. Should be anatomically sound
    • define the source vessel (vascular anatomy)
    • define the anatomic muscle dissected if any (surgical anatomy)
    • define the type of perforator (perforator anatomy)
  1. Should be clinically significant in stating whether superfine micro-vascular anastomosis  is required or not.

According to the Gent consensus, a perforator flap should be named after the nutrient artery or vessels and not after the underlying muscle. If there is a potential to harvest multiple perforator flaps from one vessel, the name of each flap should be based on its anatomical region or muscle. For example, the nutrient vessel [lateral circumflex femoral artery (LCFA)] plus the muscle name (vastus – lateralis) yields the flap name, LCFAP-vl. This classification does not however, define the type of perforator that has been dissected- septocutaneous / musculocutaneous and does not mention the level of dissection – perforator level/ source vessel level.

Sinna et al, proposed the following modifications to the above nomenclature:

At least three elements must be accurately described.

  1. The first term specifies the name of the proximal vessel, as suggested by Hallock.
  2. The second term defines the extent of vascular dissection, as suggested by Kim.
  3. The third term identifies the muscle in addition to the type of perforator (a musculocutaneous, septocutaneous, or direct cutaneous perforator), characterized in the Gent consensus.

flaps-perforators

J T Kim, provides an anatomical classification system which signifies the course of perforator, its source vessel and the muscle being traversed if any.

A: DIVISIONS OF NOMENCLATURE

Perforator flaps can be categorized into :

  1. When based on DCp/ SCp, it is named according to the proximal vessel name.
  2. When based on MCp, it is named according to the muscle it perforates.
  3. Whether the proximal source vessel is harvested or dissection is stopped at perforator level itself would indicate the level of anastomosis that is at ‘perforator level’ or ‘source vessel’ level; the former is technically superior as it needs super microsurgical anastomosis. This forms the basis of nomenclature of the flap whether it is a perforator based flap (anastomosis at perforator level) or a perforator flap (anastomosis at  source vessel level).

B: BASIS OF NOMENCLATURE

DCp is the perforator sprouting from the proximal vessel to dermis without traversing the muscle or deep fascia, and mostly found in face, perineum and so on.

SCp is the one piercing the intermuscular septum

MCp, is one piercing the muscle and requires intramuscular dissection of the perforator.

C: APPLICATION OF NOMENCLATURE

  1. LATERAL THORACIC REGION

In accordance with Kim’s classification, flaps from the lateral thoracic region could thus be described and comprehended in the following manner:

“Latissimus dorsi perforator-based flap”: based on a musculocutaneous perforator and dissection stopped at the level of perforator itself.

“Latissimus dorsi perforator flap”: based on a musculocutaneous perforator and dissection done till the source vessel.

“Thoracodorsal perforator based flap”: based on a septocutaneous perforator and dissection stopped at the level of perforator itself, no dissection of the main proximal vessel.

“Thoracodorsal perforator flap”: based on a septocutaneous perforator, dissection done till source vessel.

“Lateral thoracic perforator flap”: based on a direct cutaneous perforator from the lateral thoracic artery, dissection is done till the proximal artery.

Figures below first show the basic design of the branches that ensue from the femoral artery. The wonder that is natural symmetry, means that the same figure can be used to describe the arteries around the shoulder or around the lateral thoracic region by changing the names of the vessels. Nomenclature of perforator flaps harvested from the lateral thoracic region; as well as flaps based on the femoral system are also included in the figures.

1_f-cutaneous-design

2_f-cutaneous-design

3_f-cutaneous-design

  1. LOWER LIMB

In the thigh, the anterolateral thigh flap can be elevated based on SCp or MCp:

‘vastus lateralis perforator flap’ based on MCp, dissection done till source vessel

‘vastus lateralis perforator based flap’ based on MCp, dissection stopped at perforator level

‘lateral circumflex femoral perforator flap’: based on SCp, dissection done till source vessel

‘lateral circumflex femoral perforator based flap’: based on SCp with dissection stopped at perforator level

  1. UPPER LIMB

Similarly, in the upper limb, flaps can be described easily and with uniformity.

‘radial perforator flap’, based on SCp from radial artery, dissection till source vessel

‘flexor carpi radialis perforator flap’: based on MCp perforating the flexor carpi radialis, dissection till source vessel

CONCLUSION

  1. New Nomenclature of Perforator Flap: scientific, accurate, anatomical, consistent and simple.
  2. Perforator flaps:
  • MCp: name of muscle + perforator flap
  • SCp / DCp: name of source artery + perforator flap
  1. Perforator based flap: no sacrifice of source artery, suffix of anatomic direction or area
  • MCp: name of muscle + perforator based flap
  • SCp / DCp: name of source artery + perforator based flap

The above nomenclature proposed by Kim is easy to follow and can be comprehended by surgeons across the globe. Uniformity in nomenclature of perforator flaps cannot be over- emphasized as perforator flaps are the order of the day in reconstructive surgery.

SUGGESTED READING

  1. Koshima I, Soeda S. Inferior epigastric artery skin flaps without rectus abdominis muscle. Br J Plast Surg. 1989;42:645–648.
  1. Taylor GI. The angiosomes of the body and their supply to perforator flaps. Clin Plast Surg. 2003;30:331–342
  1. Wei FC, Mardini S. Free-style free flaps. Plast Reconstr Surg. 2004;114:910–916
  1. Blondeel PN, Van Landuyt KH, Monstrey SJ, et al. The “Gent” consensus on perforator flap terminology: Preliminary definitions. Plast Reconstr Surg. 2003;112:1378–1383; discussion 1384–1387.
  1. Sinna R, et al. What Should Define a “Perforator Flap”? Plastic and Reconstructive Surgery December 2010.vol 126;6: 2258-2263
  1. Kim JT. New nomenclature concept of perforator flap. Br J Plast Surg. 2005;58:431–440.

August 10, 2016

58. Major Reconstructive Surgery Following Excision of Malignant Tumors of the Head, Face and the Neck: The Indian experience

Filed under: Chapter 58,Uncategorized — ravinthatte @ 9:35 am

Introduction and Acknowledgements

Prabha Yadav is the head of the department of reconstructive surgery at the Tata cancer hospital in Mumbai India and together with her two junior consultants Vinay Shankdhar and Dushyat Jaiswal perform on an average six hundred reconstructions in one year a majority of which follow excisions for cancers in the head and neck region. She has kindly consented to share their experience as well as the vast clinical material in their collection without which this chapter could not have been written.

Slide1

Once their material was sifted through the compiler of these notes met with Dr. Yadav’s senior fellow Amit Patil and her two senior residents, Rajendra Dhondge, Saumya Mathews, on several occasions to ascertain how a flap or flaps were chosen for a particular defect as well as to arrive at a cogent bibliography as to how we have arrived at the present stage of our reconstructive choices. What surprised the compiler of these notes was that the Tata group was relying on only three flaps for almost ninety percent of their reconstructive work namely the radial artery forearm flap, the free micro vascular fibular transfer and the lateral thigh flap. They are shown below in the sequence that they have been mentioned.

Radial artery forearm flap

Slide2

Fibula osteocutaneous flap

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Anterio lateral thigh flap

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One obvious advantage of this or these choices is that the operative areas are wide apart allowing two teams to operate simultaneously. The flap can be developed once the approximate size of the defect is known and the vessels at the recipient site can be made ready after the tumor is excised saving considerable amount of time so crucial for patients rendered weak by their disease. To a question as to what they would fall back upon in case of a major loss of one or more flaps in a given case the answer was equally surprising. The team invariably would use these same flaps from the opposite side of the body after debridement of the dead tissue in the recipient area, suitable antibiotics and a waiting period.  Salvage flaps such as a pectoralis major flap would only be a last choice. As to whether reconstruction with flaps hides early recurrences, the oncologist in the team said that all flaps might hinder recognition of recurrences but immediate reconstruction allows for ancillary radio-therapy to begin immediately and therefore recurrences have fallen in general.

Pectoralis major flap

Slide7

This discussion is narrated here to indicate that free micro vascular flaps are now as far as possible the first choice even in difficult situations. This certainly is a revolution particularly in India which continues to be a developing country. The days when tissue was moved in stages to the defect during which patients were unable to swallow properly or covered their faces for long durations and many times continued to stay in the ward till the reconstruction was complete are now history.

Slide8

Another point that emerged during the discussion was the nature of cancers that were seen at the Tata cancer hospital and the infrequency of cancers of the skin including melanomas. Their work load consisted mainly of cancers of the buccal mucosa as well as that of the tongue and the gingiva or the mandible and many of them were aggressive. The title of this chapter was therefore modified to call it the Indian experience. Examples of some infrequent tumors of the skin are presented below:

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A brief history of pedicle flaps

It is on this background that we launched a search for a comprehensive history of pedicle flaps when we came across the introduction to the Encyclopedia of flaps; editors Strauch Vasconez and Hall Findlay, Lippincot Raven 1998 by R.A. Chace to realise that the thirty years beginning with 1968 were for plastic surgery what the first thirty years of the same century was for physics. The introduction begins with Sushruta’s forehead flap from the pre-Christian era and lauds it because it is still used today.

Slide15

Though it is certain that Sushruta described the cheek flap for reconstruction of the nose historians have not found a description of the forehead flap in his treatise; However a fragment survives of a conversation between a student and Sushruta in which the student wonders as to how such a flap survives Sushruta answers by saying that the flap survives by way of its continuity with the skin from which it is fashioned. The original terse aphorism is in Sanskrit: सानुबंधेन जीवित:

Sushruta’s verse does not however comment on the nature of the continuity; or the bridge. Be that as it may the sudden appearance of this flap in 18th century in India almost certainly is not an accident. The technique probably lay hidden but was carried by way of an oral tradition from ancient times. Curiously this bridge or the base; or the continuity that Sushrut alluded to remained unexplored for almost two thousand years until Milton in 1968 showed the fallacy of the length breadth ratio in the planning of flaps. The one to one ratio between the base and the length therefore was no longer sacrosanct if a sizable vessel ran along the length of the flap from its base. Milton proved this in an experiment on pigs by cutting flaps of various dimensions on the back of the animal and demonstrated that disproportionately long flaps which had survived in the experiment had a segmental vessel running within them.

Slide16

This discovery was preceded by a prescient observation nearly hundred years earlier in 1863 by John Wood that the inclusion of the superficial inferior epigastric artery in a flap in the lower abdomen leads to a better survival of the flap. Strangely he called this flap a groin flap. Incidentally a flap based the superficial external pudendal artery (s.e.p.a.) from the lower abdomen was described by Dias and Dias and Patil in 1984 and 1987.

Slide17

Slide18 To pick up the link again In 1920 Sir Harold Gillies Slide19 had stated that in general a flap should not be larger than the width of the flap but later added a rider that a longer flap could be raised if the flap contained in its base a larger vascular pedicle such as the superficial temporal artery. In 1931 Jacques Joseph using illustrations from Manchos Atlas of Cutaneous Vessels (1889) described the delto-pectoral-flap later imaginatively used for reconstruction in the head face and the neck by Bakamjian in 1965.The flap is shown in the figure below.

Slide21

Slide22 Almost certainly as a consequence of Milton’s work mentioned earlier Macgregor and Jackson described the groin flap in 1972 and in the same year Macgregor and Morgan coined the term axial pattern flap the word axial denoting the presence of a vessel along the longer axis of the flap.

Slide23

Slide24 In 1973 Daniel and Taylor reported the first free micro vascular flap transfer of an axial pattern flap which incidentally was the groin flap. The groin flap as shown in the above drawing is a flap supplied by a direct cutaneous vessel the superficial circumflex iliac artery a branch of the femoral artery and runs in the subcutaneous tissue almost from its beginning unlike a majority of other vessels which perforate deeper structures such as deep fascia and muscle to supply the skin (please see note in a later paragraph about the vascularity of faciocutaneous flaps). Incidentally a free flap was attempted earlier by Antia and Buch in 1970 where  adipo-fascial tissue from the lower abdomen was transferred for a soft tissue defect of the face but the attempt failed.

The role of fascia in cutaneous flaps

Slide25 Ponten in 1981 included the fascia in a flap in the leg below the knee to demonstrate that the standard one to one ratio can be exceeded up to one as to three and longer flaps can be successfully designed and rotated for local use. Barclay and others in 1983 reported twelve cases of cross leg fasciocutaneous flaps. In 1984 Thatte and Laud showed that fascia alone can be moved based superiorly as a transposition flap, to be covered by a split skin graft to heal wounds on the anterior surface of the lower leg.

Slide26

Thatte et al, in two papers in 1986 showed that fasciocutaneous cross leg flaps can be detached in ten days by incorporating a distal fascial extension to the main flap which was buried in the normal tissue beyond the defect for faster revascularization.

Slide27

Thatte et al also used the anterior rectus sheath to cover a wound on the volar surface of the palm which in turn was covered by a skin graft to avoid too much bulk that a conventional flap carried. In the case reported in that paper in 1986 the wound on the dorsum of the hand was covered by the S.E.P.A. flap described earlier in this chapter (superfial external pudendal artery flap).

Slide28

Around this time a series of papers were published underlying the importance of the deep fascia together with its rich vascularity because of a main vessel which ran underneath it and which in turn pierced it to form a rich plexus on the outer surface of this fascia This fascia could be in the form of an intermuscular septum in which case the vessel that arose from the main underlining vessel and which penetrated the fascial septum was called a septocutaneous vessel and its  branches that supplied the subcutaneous tissue and skin came to be called as perforators. Occasionally these septocutaneous vessels penetrated the adjoining muscle to appear on its surface by penetrating the fascia of the muscle; or the epimyceum to supply the skin.

The blood supply to the skin and subcutaneous tissue that resulted from this vascular architecture was not random but had a certain territorial arrangement. Several papers were published on these vascular territories in various parts of the body and to name only one Whetzel et al in 1997 mapped the areas of blood supplying the lower leg which corresponded with specific septocutaneous vessels.

Slide29

Taylor in 2003 in his seminal work called these territories angiosomes and showed that they were connected by way of what he called choke vessels which otherwise lie dormant but can be activated by a delaying procedure in which two adjoining angiosomes can be possibly raised as a single flap.

Slide30

Taylor most notably demonstrated the presence of approximately four hundred perforators in the human body on which flaps can be based. The most commonly used fasciocutaneous flap as of today is the lateral thigh flap originally described by Baek (1984) and later became popular though the work of Song et al and Koshima et al (1984/1989).

 Muscle flaps 

Slide31 Unlike the comparatively short and a somewhat nuanced history of fasciocutaneous flaps over the last twenty years the history of muscle flaps is longer and more robust and direct. Ombredanne in 1906 folded the pectoralis minor muscle on itself by cutting its humeral attachment to create a breast mound after a mastectomy. In the same year Tanzini used the latissimus dorsi muscle for the same purpose as a transposition flap after a mastectomy. Six years later in 1912 Stephano d Estes used the same muscle this time together with its overlying skin to create a new breast. It is not quite clear as to whether these surgeons were aware of the exact axial nature of the blood supply of the muscle and and\or in what manner the overlying skin was supplied by blood vessels that emerged from the muscle. In 1955 Neal Owens used a composite flap of the sterno mastoid muscle together with the platysma and the overlying skin based superiorly to cover defects in the face. However the muscle flap technique gathered pace after Ger used muscle flaps for compound defects in the lower leg a notoriously difficult area for reconstructive surgery. Orticochea ventured even further by raising a superiorly based gracilis muscle flap together with its overlying skin and used it as a cross leg flap in 1972. All these efforts were somewhat empirical in that the exact blood supply of various muscles as well as the territories of skin that got supplied through the muscles was not known.

Slide32 McCraw and Dibell put the whole story together by publishing their work on musculocutaneous territories in 1977. One of the more high profile musculocutaneous flaps was the one in which soft tissue and skin in the lower abdomen based on its blood supply emerging from the rectus abdominus was transferred together with the muscle to create the breast mound the rectus being supplied by the superior epigastric artery (1983 Bunkis et al. and Elliot and Hamtrampf). The same soft tissue in the lower abdomen is now being transferred to the area of the breast as a free microvascular flap because it is supplied by a perforator which arises from the inferior epigastric artery. This avoids sacrificing a muscle. Generally speaking the role of muscle and musculocutaneous flaps in closing defects has diminished considerably and muscle flaps are now used mainly as a pedicled local flap or as a free flap with its nerve kept intact as a dynamic transfer. For example, the gracilis muscle is used locally to reconstruct a dynamic anal sphincter or the same muscle is moved by way of a free micro vascular transfer and later neurotised at the new site for restoring animation in the face following a facial palsy. Such a procedure can also be done to restore motion across a joint in cases such as a palsy of the brachial plexus. Here too the most frequently used muscle is the Gracilis muscle.

Slide33

Slide34 Flaps of an entirely different genre namely the pedicled venous flaps and the neurocutaneous flaps are included here only to complete this review though they are not amenable to a free vascular transfer. The pedicled fasciocutaeous venous flap has only a large vein in the base of the flap without any known artery or a perforator. Two such fairly large flaps based on the cephalic and the saphenous vein in the hand and the leg have been successfully employed for adjacent defects (Thatte and Thatte et al (1992-1994, 1998-2000). Their circulatory physiology is somewhat obscure though three possible explanations have been offered by experimental work done mainly by Mukund Thatte.

Slide35

The neurocutaneous flap described by Masquelet et al 1992 and Bertelli et al 1992 has a far better explanation in that vessels are laid pari pasu with the nerve as it leads with its ingrained genetic developmental impulse during the embryological stages of the deposition of tissue and consequently the nerve has a profuse blood supply both within itself and in its surroundings to enable it to carry out its high metabolic functions in a chain linked fashion and therefore can support a flap of the surrounding tissue. This kind of transfer has the added advantage of the flap being a sensate flap because most neurocutaneous flaps are based on subcutaneous sensory nerves.

Slide36

Neither the pedicled venous nor the neurocutaneous flap can be transferred as free flaps. Since this discussion began with Sushruta’s forehead flap a technique is presented below in which two flaps have been fashioned from this area.

Slide37

While plastic surgeons have dramatically improved their expertise in reconstructing flat surfaces both for cover and lining as for example of the oral cavity or in filling a dead space or infected cavities as well as reimplanting and transplanting of composite tissue such as limbs toes or fingers they have not had such success in creating functioning tubes. Hypospadias is a prime example. In the more proximal variety of that condition for example in penoscrotal hypospadias a locally constructed skin tube is frequently bolstered by a flap of the dartos fascia from under the median raphe of the scrotum to prevent disruption leading to formation of fistulae. Reconstruction of the oesophagus in the neck is a far more formidable proposition ideally requiring immediate reconstruction. More often than not the local tissue might be short or scarred and the patient might also need post-operative radiation. All methods in the past which invariably used some form of a skin tube either created locally or transported from a distance and then covered by a flap have had indifferent results and were time consuming as well as cumbersome. One of the more dramatic improvements in this regard has been the free microvascular transfer of a jejunal loop with almost zero morbidity in digestive function. Also this is a composite tissue in many ways resembling the excised oesophagus. Whether the isoperistatically placed jejunal tube does actually participates in the act of swallowing is somewhat doubtful because it has lost its nerves in the process of its transfer but the transplanted living jejunal tube probably compensates by being an open and passive conduit and allows the forward motion generated in the proximal segment.

Slide38

A few examples of reconstructive procedures following excisions of malignant tumors around the oral cavity are presented below.

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A small chapter following this will include some alternative methods of reconstruction in the region of the head and neck and a possible systematic nomenclature of fasciocutaneous flaps.

April 13, 2016

57. Orthognathic Surgery and Surgical Distraction for Deformities in Clefts of the Lip and Palate

Filed under: Chapter 57,Uncategorized — ravinthatte @ 4:53 am

57. Orthognathic Surgery and Surgical Distraction for Deformities
in Clefts of the Lip and Palate

  1. Chintamani Kale and Heemanshu Dave, the two orthodontists who contributed to the preceding chapter have continued to help in this chapter. Ashok Dabir, a senior maxillofacial surgeon in Mumbai figures in this chapter as a very important guide. Nitin Mokal, craniofacial plastic surgeon, who has been a contributor to these short notes in the past has also helped a great deal. The chapter has evolved after several joint meetings between them and the compiler of these short notes. The idea of these meetings was to distill what is germane to deformities of the jaw as related to patients with clefts from the vast literature on Orthognathic Surgery. It became apparent as the discussions progressed that the orthodontist acts like a physician to the maxillofacial surgeon.
  2. The word ‘ortho’ of Greek origin generally means straight, right, correct or proportionate as opposed to twisted or crooked. The word ‘gnathis’, also of Greek origin derives from the original ‘gnathos’ to mean the jaw. The restoration of the jaws to their rightful position and form by surgical methods is orthognathic surgery. The subject of the previous chapter, Orthodontics for patients with clefts dealt with restoration of dental alignment of the two jaws. In many instances the two specialities, orthodontic as well as orthognathic, overlap each other and therefore Orthognathic surgery is also called ‘dentofacial’ surgery. The nature of the alignment of the teeth and their location (please see Angle’s classification in the previous chapter) also depends on amongst other things the projection of the two jaws. As a general principle when orthodontic treatment is not enough to alter appearance and dental alignment, orthognathic surgery can help. In many instances orthodontic treatment is begun knowing in advance that some form of orthognathic surgery might be required later. In orthognathic surgery the jaws are moved after strategic cuts in ‘one go’. The jaws can also be moved slowly after these cuts by what is known as slow distraction.
  3. Orthodontic movement of teeth has possibilities and limitations both. In fact Profit and Ackerman, from the United States of America drew what is known as an “envelope” to generally narrate how much of the dental discrepancy can be treated by orthodontia, under what circumstances moulding and non-surgical distraction become necessary and when both are not feasible how maxillofacial surgery including surgical distraction becomes a necessity. The vertical and horizontal axis in the envelop represent ideal positions of the teeth (please see figures below). For example, backward movement of 7 mm and forward movement of 2 mm of the upper incisors is possible by orthodontic treatment alone. Similarly, its downward and upward movement possible by orthodontic treatment is 4 mm and 2 mm respectively. For the lower mandibular incisor, the backward movement is restricted to 3 mm and the forward movement to 5 mm. Similarly, the inferior movement possible is 4 mm and the upward movement a mere 2 mm (please see figures below).

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  1. During the phase of development till about 18 years of age, when the jaws are more pliable pending final ossification, some forward movement of teeth and the jaw can be achieved by traction on the upper jaw without any surgical cut. Since the chapter deals with deformities involving clefts in the maxillary bone, and because in this condition the upper jaw is unable to grow normally both because of inherent deficiency and surgical treatment resulting in raw areas and scars, a contraption to pull the jaw forwards in a patient is shown below. The compliance for this treatment is often unsatisfactory and relapse is known because as soon as the forward displacement is achieved and the treatment is stopped, the maxilla may relapse somewhat to an unfavourable posterior position. In the mandible which is unaffected in its normal forward growth attempts can be made to restrict this growth to achieve a match with the maxilla which may never assume its normal forward growth. Also the mandible in order to achieve normal lip closure tends to rotate upwards resulting in an upward tilt of the symphyseal region. A maxillary appliance can be incorporated with a mandibular extension to reverse these two abnormalities as shown in the figures below.

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All illustrations of orthodontic treatment courtesy Chintamani Kale, Orthodontist, Mumbai.

  1. When the discrepancy exceeds what has been narrated so far, surgical intervention is needed. It might be in the nature of surgical distraction following an osteotomy or a corticotomy or osteotomy followed by immediate surgical advancement. For this purpose, to gauge the mismatch between the maxillary and mandibular skeleton, fixed points are marked by way on a tracing of lateral cephalogram. These multiple points and the angles that they make will determine the nature of surgery. When seen altogether these figures appear like a Byzantine puzzle for a beginner or an average post-graduate student. They have been therefore for convenience of the reader marked four or five points at a time and then all together. Additional figures show the angles and their interpretations so that surgery can be planned.

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The drawings of cephalometric analysis and their interpretation courtesy Heemanshu Dave, orthodontist, Mumbai.

  1. A survey of literature as well as major works on Orthognathic surgery reveal that pages devoted to surgery on deformities following clefts are less than two or three percent probably representing their smaller numbers. One reason could be that when such deformities were very common, sometimes even grotesque, orthagnathic surgery was in a stage of early development. On the other hand as clefts came to be treated with fewer raw areas following surgery and orthodontic treatment improved the incidence of major deformities may have fallen. It is generally accepted that both orthognathic slow distraction as well as orthognathic surgery with immediate movement of the bone, should be undertaken around 18 years of age when facial growth is complete. Only when the deformity is severe and has a functional element, for example difficulty in swallowing, chewing, breathing (sometimes mild sleep apnea) or when the deformity is so severe that it leads to psycho-social problems should these procedures be undertaken during the growing years, after advising the parents that the procedure might have to be repeated. Unlike orthognathic surgery of the facial skeleton in non-cleft patients deformities in patients with clefts have some special features.

a) The soft tissue envelope of the face may stretch with distraction or surgery but might shrink after the final orthodontic appliance to maintain the correction is removed.

b) At least part of the bony envelope, mostly mucoperiosteal, is inevitably scarred following repair of the cleft leading to difficulty in moving the bone.

c) Such scarring or repair might have compromised vascular environment of the bone which may compel a change of design from Le Forte 1 osteotomy to Le Forte 2 osteotomy (please see arrow in figures).

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d) Fistulae between the oral and the nasal cavity might need import of tissue but even here a part of the cover or lining may have been borrowed from the local area leading to shortage

e) Alveolar bone grafting, a procedure with a fickle outcome, might mean that the maxillary segment might not be firmly united; not an ideal situation while moving the bone ‘en block’. Fresh bone grafting might have to be done at the time of surgery

f) And lastly the other features of the face which accompany a repaired cleft such as nasal deformity or hypoplasia on the affected side unless corrected will mar the final result and may have to be performed separately particularly because almost all orthognathic surgery is done with nasal intubation.

7.   The modern orthognathic surgeon carries out a number of different surgical procedures for dento-facial deformities. There is little doubt however that the three most commonly used techniques are the Le Forte 1 maxillary osteotomy, the bilateral sagittal split ramus osteotomy of the mandible and the sliding genioplasty particularly in cases for deformities in patients with clefts. (see figures following para 10).

8.    Slide11The history of orthognathic surgery began strangely when Obwegeser, a German plastic surgeon observed a sagittal fracture of the mandible in which the anterior fragment had displaced posteriorly on the medial side of the vertical ramus. A recent clinical case similar to what Obwegeser might have seen is presented below.

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9.    From then onwards, it was realized that both the maxilla as well as the mandible could be osteotomised at strategic points in order to achieve favourable displacement of the two osteotomised segments to achieve improvement of function, better dental occlusion and an improved appearance.

10.    In clefts of the maxillary bone the commonest deformity that is encountered is a relatively posterior position of the maxilla due to inherent deficiency as well as the iatrogenic assault following surgery and subsequent scarring. A standard case of maxillary advancement is presented below. In the mandible this maxillary retrusion results in what is called a relative mandibular prognathism because it continues to grow unhindered compared to the maxilla and in fact it might rotate upwards naturally in order to occlude the maxillary dentition (Sometimes there is a true mandibular prognathism in addition to the maxillary retrognathism because the mandible growth is unimpeded due to a negative vertical overbite). In the mandible therefore, as opposed to the maxilla, surgery is undertaken to effect a setback so that it will match the maxilla which has already been moved forwards but not enough to match its mandibular counterpart (see figures).

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The following illustrations show the steps of a bilateral sagittal split-osteotomy of the mandible.

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A clinical series of a patient with a standard deformity in a case of unilateral cleft of the lip and palate with a retruded maxilla and a somewhat prominent mandible who required both, maxillary advancement and a mandibular setback is shown in the following figures.

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All cases of orthognathic surgery courtesy Ashok Dabir, Oro-maxillofacial surgeon, Mumbai

  1. Surgical distraction involves an ostetomy or corticotomy in situ followed by application of an appliance which opens or widens slowly. It is usually accompanied by osteogenesis in the bony gap that forms slowly but simultaneously as distraction progresses, a principle that Ilizarov demonstrated in the long bones. Several examples of maxillary or mandibular distractions are illustrated below.

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  1. However in exceptional circumstances when a maxillofacial deformity endangers life for example in Pierre Robin syndrome, after conservative treatment fails distraction of the short mandible remains the only viable option and can be undertaken even in small babies.

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All case illustrations of post-surgical distraction courtesy Nitin Mokal, craniofacial and plastic surgeon, Mumbai.

Nisheet Agni, a maxillofacial surgeon from Mumbai, one of the reviewers of this chapter, adds the following:

Conventional Orthognathic surgery for management of cleft maxillary hypoplasia largely corrects the dental discrepancy (reverse overjet). However, it has a tendency to cause some deleterious effects on the speech of the patient. To avoid it recently a procedure termed as ANTERIOR MAXILLARY DISTRACTION is being done. The anterior maxillary segment is osteotomized and an intra-oral distraction device which is custom made using an orthodontic expansion screw is employed to distract the osteotomized segment and correct the reverse overjet. Like conventional Lefort I advancement, it also effectively corrects the dental discrepancy. Since it doesn’t move the posterior aspect of the maxilla and the soft palatal musculature it doesn’t cause any worsening of speech. In fact it does improve speech to an extent because it creates additional space for the tongue movements (please refer to the chapter, Cleft Palate and Speech).

This case was operated by Dr. Sunil Richardson, Maxillofacial Surgeon, Nagercoil, Tamil Nadu and was assisted by Nisheet Agni while he did a fellowship under Dr. Richardson.

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December 30, 2014

51. Cleft Lip and Palate, Embryology and Classification

Filed under: Chapter 51,Uncategorized — ravinthatte @ 4:56 am

51. Cleft lip and palate, embryology and classification

  1. After a lifetime spent doing autopsies, William Boyd, the eminent pathologist of the last century was left wondering as to how it is that people live rather than die. Since then human affairs have become far more complicated giving birth to an adage also called Murphy’s Law (as applicable to the mechanical world): that if something can go wrong, it will. In very recent times, Atul Gawande has written some very well researched and insightful books which include “Checklist” and “Complications” which show a way to avoid errors in clinical practice.

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  1. In the in vivo scenario the embryological development of a human foetus is so complicated that one is left wondering at the small number of congenital anomalies that occur in live births. The mystery is somewhat explained when we view an interesting statistical detail, that of the incidence of one holo-prosencephaly in two hundred and fifty aborted foetuses. Obviously nature’s sensitive signaling does not allow foetuses with major craniofacial abnormalities to progress to full term. The development of the craniofacial skeleton is hugely complex and consists of formation of cellular masses, their division, their growth, migration and then fusion at a later date. This process is vulnerable to disruption at every stage by a faulty gene (a priori) or because of abnormal mutations due to internal or external factors. The latter are called environmental (teratogenic) (see para 7), the former occur due to a faulty protein metabolism in the basement membrane of the genetic cells. There is little clarity of how this comes about.
  2. When a sperm fertilizes an ovum in the fallopian tube (Fig. 1) to produce a zygote, the die is cast. Environmental factors cast their shadow only later till about three months of gestation. The zygote as it travels through the uterine cavity has already started multiplying and this group of cells is called a morula. The morula develops a fluid layer within and is then called a blastocyst which has an outer layer of cells called trophoblast which attaches itself to the uterine wall and forms the placental structures. The inner layer is the embryoblast which will form the embryo (Fig. 2). During its very early stages the cells of this structure undergo what is known as gastrulation in which the precursors of the three defining layers of the body, ectoderm, mesoderm and endoderm come to be differentiated (Fig. 3).

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  1. From here onwards the embryo develops into a rostral (head) and a caudal (tail) part which are quite distinct and their junction is where the oral pit is located. The development of the caudal part is simpler. It grows rostral wards, develops somites on either side to develop limbs and the segmental thoracic cage.

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  1. The development of the rostral part is more complicated, the ectoderm in the future neural part which will form the brain leads the way and forms two hillocks on either side of its own median plate (Fig. 6). The hillocks grow one on the other (Fig. 7), turn on themselves medially and subsequently a tube is formed (Fig. 8-9). The failure to form a tube causes deformities such as anencephaly. These cells are called neuroectoderm. The neuroectodermal cells have a pluripotent character and develop also into mesoderm and endoderm, the latter forming the lining of the gut beginning at the gums (where the outer epithelium represents the ectoderm, the muscles the mesoderm and the inner mucosa the endoderm) (Fig. 10). The mesoderm forms the bulk of the bilateral processes which migrate from the central tube; in the beginning centrifugally. The bilateral character of the embryo begins early and allows the two parts of the brain to separate failing which deformities such as micro-cephaly or Cyclops develop (holo-prosencephaly) and usually result in unviable fetuses. It is from the lateral processes on either side made of the pluripotent (referred to earlier as gastrulation) neuroectodermal tissue that the face develops, expanding at first and then moving centripetally to fuse with the descending median part of the neuroectoderm (Fig. 11-12). A craniofacial cleft forms when this fusion is disrupted (please see chapter on Origin of Craniofacial Clefts). Clefts of the lip and palate are only one such malformation of the many that occur along the way and essentially involve only the maxillary and the median nasal process and the disruption involving them. Basically the malformation either results because there is an inherent deficiency of the fusing process of genetic origin or when the process of fusion is interrupted by causes which occur later on.

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6.  While the morpho-genetic centres that form the middle-third of the face have now been identified, there is some confusion about the nomenclature as well as the source of these morpho-genetic centres. In the main the fronto-nasal process from the median part of the pluripotent neuroectoderm as it migrates downwards forms the pre-maxilla, the vomer and parts of the primary nasal cartilage as well as the columella of the nose and the philtrum. The rest i.e. the maxilla, the visible part of the nose and the lateral lip form from the two (bilaterally disposed) maxillary processes. While some source the formation of the nose to the median and lateral nasal processes as a part of one fronto-nasal process, the others include the two nasal processes as part of the maxillary processes. The incisor foramen which comes to lie between the pre-maxilla in front (from the fronto-nasal process) and the two palatine processes of the maxilla (from the maxillary processes) is important because the process of fusion anterior to what will become the incisor foramen occurs before the fusion of structures behind the incisor foramen. This sequence has given birth to the terms primary palate (earlier fusion at 6 weeks) and secondary palate (later fusion at 8 weeks) and is used in classifying clefts (clefts of the primary or secondary or both) (Fig. 13-20).

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  1. To paraphrase the legendary plastic surgeon Millard (Cleft Craft, 1976, Vol. 1, Little Brown and Co.), “embryology is important but the surgeon is left with a hole to treat for which a knowledge of what is distorted and/or missing is important because that is the clay with which the surgeon must deal and create what should have been but did not happen. ACH Watson who studied under Millard mentions rather pithily that although there have been significant advances in the last twenty years in several aspects of management of clefts, overall improvement in the scientific basis has been disappointing. This statement came in the year 2001 (Management of Cleft Lip and Palate, Whurr Publishers) but the situation has not changed very much judging by the number of protocols and variations that one finds in the treatment of cleft lip and palate.

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  1. While classification is important for record keeping and subsequent analysis of the results, on the ground that rationale is very difficult to adhere to because in the past too many surgeons operated on far too few patients and did not really adhere to a fixed protocol. Additionally an anatomical classification is hardly a guide to what is present on either side of the cleft. The quality and quantity of muscle for e.g. in the cleft of the soft palate can never be estimated in real terms. To take another example the obliquity of the cleft in the lip is no guide to the shortage of tissue within it and therefore the results will vary though they belong to the same group in the classification. Lastly the breadth of the cleft is so variable across the spectrum that to judge the results by where the cleft is located appears unreasonable. Anybody who has spent many a year in treating clefts will alternately experience dismay and delight at the results that come to happen even though the clefts appeared almost identical and were operated by the same technique and by the same surgeon. Deductive statistical analysis probably has limitations when a single basket has different types of fruit.
  2. The failure of fusion that causes the non-syndromic phenotype called Cleft Lip, Cleft Palate or both together is usually attributed to multiple factors. While there is enough evidence of the genetic origin of this deformity, this genetic component does not appear to have a high penetration rate along generations. But a genetic predisposition can come to manifest more frequently if environmental factors influence events in the first eight weeks of the development of the foetus. Alcohol, smoking and maternal illness such as German measles and the anti-convulsant drug phenytoin have all been suspected. On the other hand that adequate intake of folic acid immediately and before conception can reduce the incidence of clefts has been partially proven by K. Sridhar in several districts of the Tamil Nadu state in India where 90% of the deliveries either take place in a primary health centre or in a hospital.
  3. Some observations are however beyond dispute. The incidence of this deformity is high in children both of whose parents have this deformity and if one child is born with this deformity in unaffected parents the chance that one of the following siblings might have such a deformity is higher than in the general population. On the other hand why clefts of the lip (primary palate) up to the incisor foramen and even beyond occur more often on the left side is not known. The higher incidence of the clefts of the secondary palate in girls has been speculatively attributed to a peculiarity in the female foetus in which the palatine process (a part of the maxillary process) rises to become horizontal a week later than the boys. This is a crucial period during which the face is broadening and it is thought that therefore the processes are unable to meet each other and fuse.
  4. Please refer to definitions of malformation syndrome and sequence in the first chapter on Craniofacial Clefts.

August 16, 2013

36. Fractures of the Maxilla

Filed under: Chapter 36,Uncategorized — ravinthatte @ 5:55 am

36. Fractures of the Maxilla

1.   Anatomy:  The two maxillary bones are shaped like pyramids and they together form what we clinically call the maxilla. Each maxillary bone has four processes. The frontal process skirts the lateral side of the nasal bone to which it is firmly attached and is superiorly joined to the frontal bone. This attachment is very strong. The zygomatic process of the maxilla forms the medial one third of the orbital floor and it is to this part that the canthal ligament is attached. The articulation of this process to the zygoma is solid. The palatine processes of the two maxillary bones on either side join in the midline to form the anterior two-thirds of the hard palate. The alveolar process of the maxilla accommodates the upper teeth and the two alveolar processes together form the upper dental arch. Behind, in the oral cavity, the palatine processes of the maxillae are attached to the palatine bone (its horizontal part) and the vertical part of the palatine bones in turn are in close approximation to the pterygoid plates of the sphenoid and that forms the maxillary connection to the base of the skull (Fig. 1,2,3).

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2.   The maxillary bones are surrounded by strong bony buttresses in the form of its connections with the body of the zygoma on the lateral side, its frontal connection superiorly and its thick alveolar part inferiorly which abuts against the mandible. The indirect posterior connection through the palatine bone with the pterygoid plates (of the sphenoid) constitutes the buttress below the base of the skull. Within this circle of buttresses lies a hollow part in the anterior part of the maxilla, the maxillary antrum, which opens under a ridge called the middle concha which is a part of the maxilla. A groove between the nasal bones medially and the frontal process of the maxilla laterally is occupied by the naso-lacrymal duct which enters under the inferior concha which is sometimes considered a separate bone and is firmly attached to the maxilla proper. The two maxillary bones enclose the lower two-third of the nasal cavity, the upper one third being enclosed by the nasal bones (Fig. 4).

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3.   Fractures of the maxilla: It is customary to describe fractures of the maxillary bones in three categories as described by Le Forte a century ago and the classification’s utter logic was such that no other classification has replaced it.  It must be added that this classification is really a description of fractures around the middle third of the face and gives a territorial description of fractures of and around the maxilla. The classification employs three distinct planes.

4.   The first and the most inferior is the Le Forte 1 fracture, the line of which passes above the alveolar process and travels backwards and the fracture includes the area between the horizontal and vertical part of the palatine bone up to the pterygoid plates (Fig. 5). It therefore runs across the nasal cavity. Such a fracture might be incomplete and unilateral (Fig. 6). See below.

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The Le Forte 2 fracture is pyramidal in shape. The fracture line begins at the pterygoid plates travelling upwards medially to include the medial third of the orbital floor and then joining at or around the root of the nose. This fracture is more of a disjunction between the maxillary bones from the zygomatic bone laterally, the frontal bone superiorly and its sphenoidal connection posteriorly. The alveolar and the palatine processes remain intact within the fractured segment (Fig. 7). The fracture can be incomplete and on one side of the face (Fig. 8), see below.

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The Le Forte 3 fracture is not really a fracture of the maxilla but a disjunction of the maxillary and the zygomatic bone and the sphenoidal part of the orbit from the skull (Fig. 9).

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While the Le Forte classification is well set, clinically a combination of fractures can occur in this area because the nature of impact may vary. A sagittal fracture on one side is not uncommon and includes the Le Forte 1 and 2 territories (Fig. 6 and 8). The palatine processes of the maxilla in this kind of a fracture are separated at the fracture line and if the mucosa is torn the nasal and oral cavity will have a communication between them.

5.   Associated injuries and consequences: Fractured segments in the middle third of the face classically move downwards and backwards (posteriorly). The latter gives the face its dish like appearance but it is the inferior movement which gives it an elongated appearance (Fig. 10) and this stretches the soft tissues with it. A delay of several days in the treatment of these fractures will mar the aesthetic results because the soft tissue envelope of the facial bony skeleton is so snugly draped over the individual bones that it rarely recovers to its original when the bony parts are not fixed early.

The forces which cause the fractures are usually of a high velocity and can do damage to surrounding bones as well as injuries to other parts of the body. Fractures of the skeleton, intra-abdominal injuries or fractures of ribs with intra-thoracic complications must be looked for. Airway obstruction is not uncommon and the patient may be in shock. Equally important, the skull might be fractured (Fig. 11) with intra-cranial bleeding, the signs of which must be looked for and any clear nasal discharge should arouse suspicion of CSF rhinorrhoea. The orbit and the eye need particular attention.

6.   Diagnosis: Unlike fractures around the orbit or the nose where the loose palpebral skin fills up rapidly and is marked by ecchymosis the Le Forte fractures exhibit only moderate oedema unless the fracture lines pass through the orbital floor or the nose (Fig. 10). The classical feature of these fractures is the anterior open bite with the upper molars having descended abnormally  not allowing the anterior dental arch to close over the mandibular teeth. A bimanual examination with the index finger in the mouth and the thumb over the alveolar process can easily elicit a rocking movement of a part or whole of the maxilla in relation to the other bones or the skull. A crepitus might also be heard. An external digital examination might reveal gaps or steps in the bony contour. An oral examination frequently reveals torn mucosa, haematomas under intact buccal mucosa or sharp bony points at fracture sites. It is to be noted that in Le Forte 3 types of high fractures the descent of the whole of the middle third of the face occurs without a posterior and inferior tilt and the occlusion might remain normal. The advent of three dimensional computerized tomography has made the diagnosis and the nature of these fractures not only easy but precise. Old plain radiographs done with great skill are probably not done in many centres anymore and eponymous techniques such as Water’s or Caldwells’ views or the submento-vertex views may soon become historical notes. When a CT-scan is obtained it is always advisable to include the skull in the investigation and to also ask for coronal and sagittal views to demonstrate the nature of displacement of individual bones.

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7.   Treatment: The patient should be fully stablised hemodynamically prior to the surgical treatment of these fractures. Intra-cranial lesions such as cerebral oedema (sub-arachnoid hemorrhage) sub-dural or extra-dural hematomas take precedence in treatment. Occasionally if the patient is fit, fixation of skeletal fractures may be done in the same sitting if the anaesthesiologists give their consent. Quite a few of these patients may have had a tracheostomy because in the initial phases of the treatment the airway may have been compromised due to bleeding or because of intra-oral and nasal swelling. Such a tracheostomy is allowed to remain because in major fractures both oral and nasal intubation would need to be done one after the other to help fix individual bones and perform inter-maxillary fixation (see Fig. 13 to 17). A tracheostomy avoids these cumbersome changes.

That maxillo-facial fractures cannot be fixed with external plasters as for example in the limbs has always been a given for a very long time. This problem has been sorted out in the case of fractures of the face by taking help of the next unfractured stable bone, for example, the mandible below or the skull above. In a Le Forte 1 fracture for example, after reduction and restoration of normal dental occlusion the maxillary segment can be fixed to the mandible by wires or arch bars (see next chapter, Fractures of the Mandible for the technique of inter-maxillary fixation). The higher fractures could be fixed to the skull also with wires. Wires were also used to fix fractured individual segments of bones. Occasionally in the distant past, a plaster turban with embedded metal parts was used to suspend and fix these fractures with the help of subcutaneous wires or external appliances. The introduction of plates and screws of titanium of varying sizes has now overcome these cumbersome methods with an added advantage in that plates do not allow any rotational movement in the fixed fragments which wires were not successful in preventing (Fig. 13-17).

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In almost all these fractures which show some comminution cancellous bone grafts are placed in the area of natural buttresses. Representative red arrows are shown in figure 15 as an example.

8.   Access: The surgical treatment of the fractures of the maxillofacial skeleton and particularly for the middle one third of the face is done through a variety of incisions. The bicoronal incision can take care of trephining holes in the skull for craniofacial suspension and can reach up to the body of the zygoma and the lateral one third of the orbit and also allows access to the upper half of the nose (Fig. 19 and 21). The transconjunctival approach allows access to the whole of the inferior medial and lateral wall of the orbit (Fig. 20). An intra-oral incision through the superior sulcus enables the surgeon to reach the maxillary bones in almost their entirety (Fig. 18). In all the above scars remain hidden. Wounds on the face which accompany some of these injuries and which may be located over bony parts which are to undergo fixation can be used as an access. These wounds might be extended judiciously parallel or within the direction of the tension lines (see figures below).

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Post-operative care

Many a time, the actual inter-maxillary fixation is finally effected (after the arch bars have already been fixed) only after the patient comes out of anaesthesia to prevent choking due to the tongue falling back. A tongue stitch is frequently employed and brought out through a gap in the teeth. This is necessary because the tissue surrounding the oro-nasal airway is frequently swollen and is already compromised. Oral hygiene needs special attention. Brushing is permitted after the first two days and because only fluids can be taken during the duration of inter-maxillary fixation nutrition needs to be closely monitored. When plates and screws are used, inter-maxillary fixation may be removed as early as three or four weeks but if the fractures are comminuted, the additional support of the mandible helps in the healing of fractures.

Acknowledgments

The compiler of these notes thanks Nitin Mokal, Nisheet Agni and Arunesh Gupta for the illustrations. The figures of the skull are actual photographs and the idea of the fracture line has been borrowed from standard textbooks.

April 15, 2013

33. Blowout Fracture of the Orbit

Filed under: Chapter 33,Uncategorized — ravinthatte @ 9:59 am

33. Blowout Fracture of the Orbit

1.   Surgical anatomy

a.   The anterior rim of the orbit is somewhat narrower and thicker than the main orbital cavity. The cavity tapers posteriorly and somewhat medially in the form of a cone (Figure 1).

b.   The bony structure of the orbit is made up of several bones (see figures below) and is thin in the middle one third particularly the medial, inferior, lateral and superior wall in that order. The floor of the central one third of the orbital cavity is occupied by the inferior orbital fissure and is bound by a very thin part of the maxillary bone medially and the sphenoid laterally (Figure 2). On the orbits medial wall in the central one third lies a very thin bone called the lamina papyracea which in fact is the lateral part of the ethmoid bone (Figure 3). This bone encloses air cells. The whole structure is called the ethmoid sinus. Anterior to the ethmoid bone but not strictly in the central third lies the lacrimal bone which encloses the lacrimal sac. This bone is also quite thin. All in all this arrangement works like a safety mechanism.  Should the intra orbital pressure rise suddenly the thin bones give way without affecting the eyeball which is elastic because of its fluid content (aqueous and vitreous humor).

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c.   The eyeball sits in the front half of the orbit. From behind come the extra ocular muscles which drape the eyeball. This area also contains nerves, vessels, fat and some areolar tissue and is called the cone. In between the eyeball and this cone is a dense fascia called the Tenon’s capsule which together with the orbital septum in front suspends the eyeball. By a rider the extra conal tissue contains periosteum, extra conal fat as enclosed by the orbital septa and muscles such as the levator palpabrae superioris (please see previous chapter 31 on Ptosis) (Figure 4).

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2.   The mechanism of the occurrence of a Blowout Fracture: Pan-facial fractures caused by indiscriminate forces which involve the orbit do not follow a set pattern. In fact sometimes in such fractures bones or their parts which form the orbit are pushed within the orbital cavity leading to what is known as a ‘blow in’ fracture. The mechanism of a classical Blowout Fracture involves a forced sudden increase in the normal pressure within the bony orbital cavity leading to fractures allowing the contents of the orbit (both conal and extra-conal to migrate to the extra-orbital space). This migration may or may not be of functional consequence but on the whole in the classical blow out fracture usually saves the eyeball and vision. The functional anatomy of the eyeball is such that the thin part of the bone around the inferior orbital fissure in the orbits floor gives way most frequently. The classic example in modern times occurs in sports injury when an object such as a ball or a stick or a bat hits the protective orbital ring, (the convex part of such an object sometimes hitting the eyeball as well) causing the weaker part of the orbital wall (or walls) to give way. It has been argued that a direct hit to the bone particularly at the junction between the zygoma and the maxilla will cause the weakest part of the bony orbital framework to fracture and may occur in any part of the circumference of the orbits vulnerable central one-third (Figure 5 and 6).

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For example, part of the orbital contents might hit medially but rarely enter the space occupied by ethmoidal air cells and only cause a dent (Figure 7) in the lamina papyracea which buckles inwards. This is not true of the maxillary antrum which is already hollow and sits just below the floor of the orbit (Figure 8).

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Into this antrum can enter conal tissue such as fat or muscles (inferior oblique or inferior rectus). And this abnormal invagination of muscles might be further complicated by the muscles getting caught in parts of the fractured bone. Both the change of direction of the excursion of the muscle as well as the mechanical hindrance by bony parts can lead to restriction of movements normally effected by these muscles i.e. lower and upper gaze rotation (lower restriction because of change of axis of the muscle, upper restriction because the conal tissue is still stuck in the fracture of the floor – inferior rectus). The inferior oblique when stuck in the fracture will restrict the upper and outward gaze. Also as the orbital space increases the eye ball appears small as compared to the orbit and is usually denoted by the term ‘a sunken eyeball’ irrespective of where the fracture is. The migration of some intra-orbital contents also creates a similar shrinking effect. If the eyeball is greatly displaced or sunk, diplopia can result (Figures 9 & 10).

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3.   Diagnosis: The principal diagnostic features of a blowout fracture of the orbit are a sunken eye (Figures 9 and 10), restriction of the movement of the eyeball, particularly the downward or upward gaze, echymosis. If the restriction of the movement is severe, and if the eyeballs’ axis is not in consonance with the opposite fellow, will result in diplopia. CT-scans and MRI show the fractures in all its living details and the obliteration of the maxillary sinus (partial or complete) by blood or soft tissue or bony fragments, all help in the diagnosis (see Figure 11 and 12 below in the case report).

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4.   Treatment: A Blowout Fracture is best not classified because the pathology can range from a severe contusion of the floor of the orbit or a fracture ‘in situ’ without any displacement of tissue to gross fragmentation with abnormal displacement of bone, fat and muscles. The former two may not require treatment though the eye needs to be observed for a post-traumatic/inflammatory tethering. Anti-inflammatory agents might help.

5.   In the more severe forms even though diplopia is not present, and the appearance of the eyeball is acceptable, surgical restoration of the broken bone is a treatment of choice to prevent secondary enophthalmos and includes getting the herniated contents from inside the antral cavity into the orbit and then repair or seal the fractured area.

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The lamina papyracea which might have buckled in will require to be reduced and more often to be padded up. An intra-ciliary approach is frequently employed. The orbicularis oculi is split below the tarsal plate, the orbital septum which arises from the tarsus and which gets attached to the inferior border of the orbit is opened at this insertion and from here a sub-periosteal dissection is carried out to approach the pathological site. The length from the inferior orbital rim to the optic foramen is about 45 mm and the last posterior 15 mm is an “enter with care zone” for fear that the optic nerve might be injured. This part of the orbit is luckily rarely fractured because it is surrounded by dense bone. Theoretically as well as ideally the defect is best calculated volumetrically as a pre-operative step and must then be filled accordingly. Also ideally an autologous bone graft (calvarial or iliac crest) shaped properly and smoothened towards the ocular surface is placed over the defect (Figures 13, 14, 15, 16, 17 and 18).

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The orbit being a tight well occupied space, fixation of the graft or an implant is usually not required. In the case of the fractures of the floor of the orbit all structures which have migrated into the antral cavity are extracted and/or extricated from the fracture site and that this has been successfully done can be gauged by doing “a forced duction test”. This involves holding the sclera with a toothed forceps below the cornea and moving the eyeball in various directions. The wound is closed in layers in which the divided orbital septum is sutured back to the periosteum as the first step. Notice that the incisions in the skin, muscle and the orbital septum and then to the sub-periosteal area of the floor of the orbit are staggered, do not overlap each other and therefore produce a good scar. Late post-operative photographs of the case above are reproduced below (Figure 19, 20).

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Note:

1.   As in the previous chapters all injuries involving the face and the orbit need a detailed ophthalmic as well as a neurological examination.

2.   The line drawings in this chapter are not strictly proportionate to the actual measurements of the eyeball or the orbits.

3.   The diagram of the bony orbit is borrowed from Converse’s Plastic Surgery (WB Saunder’s 1990; editor Joseph G. McCarthy) and photoshopped on a computer to explain the text.

4.   The compiler of these notes thanks Shailesh Nisal of Nagpur (India) for the almost classical case report of a Blowout Fracture of the Orbit and general help in writing this chapter.

Nitin Mokal, craniofacial surgeon from Mumbai reiterates that a bone graft is always superior to any other alien material and further states that when volumetric replacement for tissues lost following the blowout mechanism is not a consideration, a thin bone graft taken from the anterior surface of the maxillary sinus through an intra-oral approach serves an excellent purpose of blocking of what has been disrupted both in the inferior as well as the medial wall of the orbit. Illustrations reproduced below also show that this procedure can be done by the transconjunctival approach and are self-explanatory.

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