Short Notes in Plastic Surgery

September 30, 2011

Split Skin grafting for Surgically created defects

Filed under: Chapter 5 — mthatte @ 4:09 am

1. A good recipient area is crucial for the take of a graft.
2. A surgically created wound (defect) is invariably superior to a granulating wound in this respect. In the extremities a defect created under a tourniquet allows a surgeon to do a neat dissection and preserves fair sized blood vessels and cutaneous nerves. Be that as may it is advisable to release the tourniquet after wrapping the defect firmly in absorbent gauze dressings and waiting for several minutes prior to looking at the wound again and do a through hemostasis before placing a graft on the wound.
3. In extremities with contractures of the skin which have been present for several months some secondary contracture of deeper structures is invariably present and this may include tendons, muscles, major vessels and nerves. It is strongly advised that the release should include the skin and at the most the fascia and no attempt is made to put any abnormal tension on these structures. After the graft takes and physiotherapy and splintage begins these secondary contractures of deeper structures will correct themselves to a very good extent. If an application of tourniquet is not possible, for example, a contracture over the groin or across the axilla liberal infiltration with a vasoconstrictor solution will allow a good dissection.
4. Most burn contracture have a plane of cleavage which when adhered to reduces bleeding to a great extent exposing healthy fat and / or fascia. It is not true that grafts do not take well on fat exposed at the time of the release of contractures.
5. Any form infiltration with a vasoconstrictor agent beyond the middle of the palm should never be done. Tourniquet at the base of fingers are not a good idea, they can be traumatic and are unreliable. If a general anesthesia is to be avoided, excellent regional blocks above the level of the arm can be employed which will allow application of a tourniquet over the arm. Too much stretching of the finger must be avoided at all costs. The blood supply of the finger though profuse is vulnerable to any swelling particularly in the distal part where it can be described as endarterial and any spasm of the digital arteries or obstruction to accompanying veins can result in rapid devascularisation. Dressings in fingers particularly “tie over pressure dressings” must be followed by a close inspection of the finger tips after the tourniquet is released. Any untoward discolouration white or pale (arterial obstruction) or blue (venous obstruction) for a period of more than fifteen minutes should be treated as an emergency and should not be treated with any drugs but should be treated by taking off the dressing if necessary under anesthesia and the finger allowed to curl up to its ‘pre-release’ state. The graft need not be removed but any blood clot under the graft should be removed by irrigation. Invariably the colour of the fingers will return to normal in a short time unless digital vessel or vessels are damaged. Even here release of tension will allow proximal collateral circulation to take over. This is best observed by a simple test of pressing the pulp of the finger. After the release of pressure if capillary circulation is intact, the finger will turn pink almost instantly. This test however cannot be applied when the finger is already very white or blue. If one or both arteries or veins are damaged and are spurting or oozing, a judgment call needs to be taken about micro vascular repair but even here procrastination is dangerous. Since it will take some time to set up the required instruments and a microscope that time may well allow the fingers to recover on their own but the surgeon must be prepared to proceed.
6. As a general rule contractures following electrical burns or any form of trauma (incised, avulsed, lacerated or mutilated) are a different ‘ball game’ altogether. These injuries have no respect for tissue planes and allow no time at all for the victim to withdraw. As opposed to this, except in blasts or emersion in hot liquids, thermal burns in a vast majority penetrate slowly and in planes, can be minimized by pouring cold water over the part. Also the agent that burns, burns itself out rather rapidly.
7. Therefore, from the above, a surgeon must be wary when releasing post traumatic or post electrical burn contractures. In several of these contractures the pathology extends below the skin, might involve tendons, muscles or bone, the scar is dense and adherent and when present in extremities might have caused damage to nerves and vessels. The defects created by release of such contractures are not suitable for treatment with a split skin graft in a vast majority of cases but will require a cover with a flap, which forms a part of these short notes in a later chapter.
8. As to when the dressing over a recipient site should be changed to inspect the graft might vary from one unit to another. Certainly they should not be disturbed for the first four days but then on if the tie over dressing is dry and there is no discomfort, the dressing can be left alone for as long as two weeks. Patients can be discharged in the intervening period. If a measurement for a static splint has been taken at the time of surgery for example and particularly in a case of contracture of the neck then the splint can be applied straight away when the dressing is removed even when there is some loss of graft. Application of these splints in the extremities, over the axilla, or the neck goes a long way in preventing re-contracture when done at the time of change of the first or second dressing.
9. Occasionally in a surgically created defect a delayed secondary grafting is done when the original lesion is infected. The classic example is that of an infective condition in hair bearing area called ‘hydradenitis suppuritiva’. This principle might also apply to some hypertrophic scars where some indolent infection surrounds buried hair follicles. Defects left behind after excising such lesions are washed and irrigated with saline, hydrogen peroxide and some organic iodine solution, and the specimen sent for a bacterial culture and antibiotic sensitivity. The defect is then dressed and is usually very clean at the end of two or three days and can be grafted quite successfully. The bacteriological report is an added insurance and a suitable antibiotic can also then be started at that time.
10. In spite of the fact that a very good hemostasis has been achieved in the recipient area most surgeons mesh their grafts. This meshing does not involve any expansion but is recommended to allow blood or fluid to ooze out under the tie over dressing and helps in the good take of a graft. Dr. V. Bhattacharya of Varanasi rightly adds that gentle saline irrigation from under the graft will help take away early micro clots.
11. When the first dressing is done the graft requires to be inspected carefully. When a graft is thick, epidermis might have peeled off though the dermis appears well taken by its pink colour. This needs to be preserved and will survive and then produce an epidermal layer over several days. Sometimes this dermis though adherent to the recipient bed is white and resembles a thick eschar or slough. This is best excised early because it can serve as a source of infection for the rest of the young graft.
12. If a skin graft will grow on its own and overcome the residual deformity because of secondary contracture remains a moot question. It is to be noted that skin grafting done in childhood in many instances does not become a source of any contracture over the years. Though the opposite, where a skin graft needs to be added is not infrequent.

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