Tissue of amputated or nonsalvageable limbs may be used for reconstruction of complex defects resulting from tumor and trauma. This is the "spare parts" concept. By definition, fillet flaps are axial-pattern flaps that can function as composite-tissue transfers. They can be used as pedicled or free flaps and are a beneficial reconstruction strategy for major defects, provided there is tissue available adjacent to these defects.From 1988 to 1999, 104 fillet flap procedures were performed on 94 patients (50 pedicled finger and toe fillets, 36 pedicled limb fillets, and 18 free microsurgical fillet flaps). Nineteen pedicled finger fillets were used for defects of the dorsum or volar aspect of the hand, and 14 digital defects and 11 defects of the forefoot were covered with pedicled fillets from adjacent toes and fingers. The average size of the defects was 23 cm2. Fourteen fingers were salvaged. Eleven ray amputations, two extended procedures for coverage of the hand, and nine forefoot amputations were prevented. In four cases, a partial or total necrosis of a fillet flap occurred (one patient with diabetic vascular disease, one with Dupuytren's contracture, and two with high-voltage electrical injuries).Thirty-six pedicled limb fillet flaps were used in 35 cases. In 12 cases, salvage of above-knee or below-knee amputated stumps was achieved with a plantar neurovascular island pedicled flap. In seven other cases, sacral, pelvic, groin, hip, abdominal wall, or lumbar defects were reconstructed with fillet-of-thigh or entire-limb fillet flaps. In five cases, defects of shoulder, head, neck, and thoracic wall were covered with upper-arm fillet flaps. In nine cases, defects of the forefoot were covered by adjacent dorsal or plantar fillet flaps. In two other cases, defects of the upper arm or the proximal forearm were reconstructed with a forearm fillet. The average size of these defects was 512 cm2. Thirteen major joints were salvaged, three stumps were lengthened, and nine foot or forefoot amputations were prevented. One partial flap necrosis occurred in a patient with a fillet-of-sole flap. In another case, wound infection required revision and above-knee amputation with removal of the flap.Nine free plantar fillet flaps were performed-five for coverage of amputation stumps and four for sacral pressure sores. Seven free forearm fillet flaps, one free flap of forearm and hand, and one forearm and distal upper-arm fillet flap were performed for defect coverage of the shoulder and neck area. The average size of these defects was 432 cm2. Four knee joints were salvaged and one above-knee stump was lengthened. No flap necrosis was observed. One patient died of acute respiratory distress syndrome 6 days after surgery. Major complications were predominantly encountered in small finger and toe fillet flaps. Overall complication rate, including wound dehiscence and secondary grafting, was 18 percent. This complication rate seems acceptable. Major complications such as flap loss, flap revision, or severe infection occurred in ...

Long-term function of three-dimensional (3D) tissue constructs depends on adequate vascularization after implantation. Accordingly, research in tissue engineering has focused on the analysis of angiogenesis. For this purpose, 2 sophisticated in vivo models (the chorioallantoic membrane and the dorsal skinfold chamber) have recently been introduced in tissue engineering research, allowing a more detailed analysis of angiogenic dysfunction and engraftment failure. To achieve vascularization of tissue constructs, several approaches are currently under investigation. These include the modification of biomaterial properties of scaffolds and the stimulation of blood vessel development and maturation by different growth factors using slow-release devices through pre-encapsulated microspheres. Moreover, new microvascular networks in tissue substitutes can be engineered by using endothelial cells and stem cells or by creating arteriovenous shunt loops. Nonetheless, the currently used techniques are not sufficient to induce the rapid vascularization necessary for an adequate cellular oxygen supply. Thus, future directions of research should focus on the creation of microvascular networks within 3D tissue constructs in vitro before implantation or by co-stimulation of angiogenesis and parenchymal cell proliferation to engineer the vascularized tissue substitute in situ.