Donor sites. Healing of Donors areas, indications and general Information
1. Traditionally split skin grafting used to be the commonest single surgical procedure performed by a plastic surgeon. With regional sub-specialisation as well as aesthetic surgery emerging as major preoccupations of plastic surgeons that situation has now changed.
2. Notwithstanding the above, the procedure of split skin grafting continues to be a major tool in various reconstructive procedures.
3. Areas from where a split skin graft is harvested are as important, if not more, than the site on which the graft is placed. These donor sites should as far as possible be in areas where they remain hidden even by informal clothes. The whole of the upper thigh (lateral preferred to medial in females) the buttocks, the lower back are used most frequently. The skin in these areas is thick and therefore has a greater dermal component and healing by regeneration is therefore faster.
4. For large granulating wounds as in burns or for wounds created by early excision of burn wounds, donor areas may be limited and therefore areas available easily depending upon the position that the patient is placed in for the procedure are used. Occasionally in large avulsion injuries of the extremities the same considerations apply. When distally based avascular skin flaps are avulsed following accidents they can be an excellent source of harvesting skin grafts and serve almost exactly the amount of skin required to close the wound.
5. Scalp is an excellent donor site for split skin grafts. Thin grafts from the scalp contain few hair follicles yet because the deep dermis of the scalp has numerous hair follicles and because the scalp is very vascular, healing is rapid. The scalp can be reused as a donor site in a few weeks time after the area is healed. This is also true of all other donor sites where the skin is thick and the grafts in the first instance were thin.
6. Though plastic surgeons are very meticulous about wound closure and abhor healing by secondary intention, ironically they of all the surgical specialities allow large areas to heal by secondary intention in donor areas created for skin grafts. Healing of donor areas occurs mainly from the bed upwards and also laterally from the edges. The thicker the graft, the greater the time for healing.
7. In healthy individuals under aseptic conditions donor areas should ideally heal uneventfully but the reality might be quite different. The donor area bleeds quite heavily particularly when the area is large and continues to bleed for several hours in spite of a pressure dressing. The donor area is a fresh wound in a highly sensate part and is almost always painful for several days. The presence of even a thin organized clot under the dressing increases the pain and a blood clot is also an excellent medium for organisms to grow. When infection establishes itself, the wound deepens delaying healing. In recent times heavy infiltration with large volumes of a dilute vasoconstrictor fluid injected subdermally with some patience, at least 10 minutes prior to harvesting the graft has ensured an almost a bloodless donor area after the graft is cut. In addition the fluid that is injected is mixed with a long acting local anesthetic agents which can take away pain for as long as forty eight hours. If surgery is done on the inferior extremities (both donor and recipient areas) under an epidural anesthesia an indwelling epidural catheter as an access for injecting more local anaesthetic agents goes a long way in increasing the comfort of the patient. Regional blocks are also employed in other parts of the body for reducing pain. In wounds which are healthy and ready to receive grafts, judiciously diluted local anesthetic agents with some sedation allow a surgeon to cut grafts up to a foot long and 4 to 6 inches wide which can then be placed on the recipient areas without any further preparation.
8. Donors areas treated with vasoconstrictor solutions can be wrapped up with any kind of dressing in two layers. Though the inner dressing is usually lubricated with vaseline; the outer dressing should be bulky and only moderate pressure is needed when tying the outer bandage. In a vast majority of patients the natural clotting mechanism takes care of the rest and the outer dressing can be removed as per the convenience of the surgeon and the patient. The inner dressing will fall off at its time 10 to 15 days for thin and intermediate grafts and longer for thicker grafts.
9. There is no documented proof to suggest that any proprietary, commercially available dressing or application is any better for healing of donor areas. For lubrication any natural fat is as good as any of the commercially available creams and it should be noted that no commercially available creams or ointments are strictly sterile from a bacterial point of view. An elastic pressure garment on limbs to support donor areas after they are healed may be advised. But when donor areas are extensive and in proximity to recipient’s areas such elastic dressings may be impractical.
10. The behaviour of a healed donor area vis-a-vis pigmentation and scarring at least to some extent remains unpredictable. While it is true that thinner grafts mean better healing in donor areas as compared to when thicker grafts are harvested, in India with darker individuals surprises await surgeons. Non-keloidal hypertrophic scars are not uncommon, so is excess pigmentation with or without a mottled appearance. Depigmentation is less common. Hypertrophic scars may benefit by using pressure garments. The treatment for these sequelae essentially remains symptomatic and empirical. No proper controlled studies of how to help prevent these consequences have been published.
11. In spite of taking all precautions, if bleeding complicates a donor area the matter should be treated in all seriousness. The area needs to be cleaned, almost always under a general anesthetic because the procedure is excruciatingly painful. If some days have lapsed a proper antibiotic preferably after a culture and antibiotic sensitivity test needs to be administered. Removal of blood clot alone may not suffice. The wounds invariably get infected and smell and may need frequent dressings.
12. Complications in a donor area do not speak well of a surgeon and to neglect a festering donor area borders on the criminal.