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An experimental, anatomical, and clinical study has confirmed the feasibility of free neurovascular flaps. The interrelationship between the cutaneous vascular and neural supply has been defined and demonstrated electrophysiologically, both in man and in experimental animals. A potential donor site in man has been explored. Free neurovascular flap transfers by microneurovascular anastomoses are technically feasible. Clinical success will occur with the identification of suitable donor sites.

Histological evidence is presented documenting the reinnervation of sensory mechanoreceptors across major histocompatibility barriers in allografted primate (baboon) skin. Meissner and pacinian corpuscles, as well as hair follicles, showed a spectrum of reinnervation by host axons. Our light and electron microscopic evidence to date has suggested that allografted Merkel cells did not survive transplantation. This, and other instances of tissue and receptor destruction resulting from histoincompatibility, indicated marked differences when skin allografts were compared to autografts with respect to the ability of host axons to locate and reinnervate sensory mechanoreceptors.

An anatomical and hemodynamic study of the deltopectoral flap in cadaver dissections and clinical cases is described. Anatomically, the deltopectoral flap represents a fusion of 3 vascular regions supplied by 3 different sets of vessels. Hemodynamically, the flap consists of a lateral cutaneous flap nourished by a medial arterial pedicle. The method of choice for delay of a deltopectoral flap is discussed.

The authors describe a technique that brings great improvement to the treatment of depressed scars. It is simple and safe as long as enough superficial tissue is available. Unequal peripheral undermining allows closure under minimal tension, is less extensive than in previously described techniques, and separates the deep scar from the superficial one.

The free flap represents a dramatic one-stage procedure for distant transfer of skin flaps. The operative technique consists of: identification of healthy recipient vessels; isolation of viable island skin flap; distant transfer followed by revascularization via microvascular anastomoses. New techniques warrant classification of free tissue transfers into single tissue transfers (skin, muscle, bone, nerve) and compound tissue transfers (osteocutaneous, musculocutaneous). When compared to conventional techniques, free flap transfers offer shorter hospitalization and immobilization as well as a greater reconstructive potential. However, their utilization mandates extensive experience in multiple microvascular techniques and clinical microsurgery.

Low-voltage electrical burns were studied in 25 pigs submitted to bilateral thigh burns using 500 volts AC for 10 seconds. In a group of 6 animals, the wounds were observed and histologic specimens obtained at different intervals during the first week. The burn measured approximately 4 cm in diameter and extended through two muscle layers. This tissue underwent further necrosis during the first 48 hours. After 2 days there was no further necrosis. In a second group, the wounds were debrided and covered with either a split-thickness skin graft or a rectus abdominis musculocutaneous flap. All wounds with flap coverage healed primarily and there was no deep necrosis. From our findings we conclude that debridement and definitive closure can safely be performed 2 days after low-voltage electrical burns.

Sensory skin flaps represent a possible solution for the paraplegic who has the problem of recurrent pressure sores. An intercostal neurovascular island flap has been used in 3 cases to provide coverage for sacral ulcers. Sensation was retained to a variable degree in both adults and children. An attempt at coverage of an ischial ulcer with an intercostal neurovascular free flap is also reported. The practical and theoretical aspects of these procedures are discussed.

Although myocutaneous flaps have evolved into a primary method for managing pressure sores, their value in reducing the recurrence rate by padding the pressure point is open to question. The use of muscle to cover a pressure point violates the normal soft-tissue coverage of a bony prominence and introduces a tissue that is exquisitely sensitive to ischemia. Clinical follow-up of patients who have had myocutaneous flaps for closure of pressure sores demonstrates almost total muscle atrophy. Although skin coverage is stable, the muscle bulk of a myocutaneous flap is not retained beyond one to two years. The long-term value of myocutaneous flaps in reducing the recurrence rate of pressure sores requires careful follow-up in major series of cases.

The vascular anatomy of the supplying vessels to the iliofemoral, the deltopectoral, the axillary, and the thoracoabdominal regions has been investigated in detail in fresh cadavers. Other donor sites were also examined. The anatomical relationship of the supplying vessels is discussed-and the design, conversion, and utilization of these skin areas as donor sites for free flap transfer are detailed. The iliofemoral region is suggested as the best donor site for most free flap procedures.

The intercostal flap has many uses for torso reconstruction, whether employed as an island flap or a free flap. With modifications, it can be used as a sensory skin flap, or as a compound osteocutaneous flap to restore stability in a chest wall construction, or as a skin flap with a permanent blood supply to provide stable cover after excision of radiation ulcers.

With the expanded surgical options provided by free tissue transfers, upper extremity reconstruction has progressed to a level of greater finesse. Recognizing the ideal tissue for restoration of function and aesthetics, thin skin dorsally and sensate glabrous skin volarly, is the first step to effective application of microsurgery in the hand. With complex deformities, all missing components must be considered and the patient's goals realistically defined. An in-depth understanding of hand function is combined with an exhaustive knowledge of free tissue donor sites and a reconstructive plan is formulated. Staged reconstruction may be necessary, depending on the complexity of the problem. Ideal donor tissues are not always available, but it is expected that advances in immunology will soon make "spare part surgery" a viable alternative.