Microsurgery
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We investigated the feasibility in rats of enhancing skin-flap prefabrication with subdermal injections of adenovirus-encoding vascular endothelial growth factor (Ad-VEGF). The left saphenous vascular pedicle was used as a source for vascular induction. A peninsular abdominal flap (8 x 8 cm) was elevated as distally based, keeping the epigastric vessels intact on both sides. ⋯ Microangiographic studies showed increased vascularity around the implanted pedicle, which was similar in all groups. However, vascularization was distributed in a larger area in the prefabricated flaps treated with Ad-VEGF. In this study, the authors demonstrated that adenovirus-mediated VEGF gene therapy increased the survival of prefabricated flaps, suggesting that it may allow prefabrication of larger flaps and have the potential to reduce the time required for flap maturation.
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Mechanical couplers are successfully used for microvascular venous anastomoses. The advantages include a simple and fast technique and a high patency rate. Couplers offer a secluded coaptation site, and might also be of use in peripheral nerve repair. ⋯ However, this did not impair axonal regeneration. Importantly, axonal outgrowth from the repair site to the surrounding tissue was not observed after coupler coaptation, but it was observed after suture repair. These results suggest that couplers may be of value for repair of nerves in adjacency to avoid axonal crisscrossing between nerves during regeneration.
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Ischemic preconditioning (IP) is defined as a brief period of ischemia ("preclamping") followed by tissue reperfusion, thereby increasing ischemic tolerance for a subsequent longer ischemic period. Several studies showed the effectiveness of classic local IP by preclamping the flap pedicle. There are two temporally and mechanically different types of IP: acute preconditioning, which is induced by preclamping the flap pedicle briefly before flap ischemia, and late preconditioning, induced by a preclamping procedure 24-48 h before flap ischemia. ⋯ The exact mechanism of "classic" as well as remote IP is not yet finally determined, although several studies demonstrated that endogenous nitric oxide plays an important role. In summary, the use of a tourniquet to induce limb ischemia before flap ischemia could provide a new, alternative, noninvasive remote IP protocol, although late remote IP might be effective only in muscle flaps. However, the possible future clinical application for late IP is elective flap surgery, whereas acute remote IP could even be used in emergency flaps.
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As microsurgery advances, microsurgical free-tissue transfers have become the reconstructive method of choice over staged or primary amputation, and enabling independent ambulation in difficult lower-extremity wounds. In this report, we present our experiences with free-tissue transfer for the reconstruction of soft-tissue defects in 13 diabetic foot ulcers. Following radical debridement, soft-tissue reconstruction was achieved in the following ways: anterolateral thigh fasciocutaneous flap in 5 patients, radial forearm fasciocutaneous flap in 3 patients, lateral arm fasciocutaneous flap in 1 patient, gracilis musculocutaneous flap in 1 patient, tensor fascia latae flap in 1 patient, deep inferior epigastric perforator flap in 1 patient, and a parascapular flap in the remaining patient. ⋯ During the follow-up period of 8 months to 2 years, no ulcer recurrence was noted, and no revascularization or vascular bypass surgery was needed before or after the free-tissue transfers. The authors conclude that free-tissue transfer for diabetic foot ulcers is a reliable procedure, despite pessimistic opinions regarding the flap survival and low limb salvage rates. It should be considered a useful reconstructive option for serious defects in well-selected cases.
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The combination of advances in microsurgery and the improvement of anesthetic management with increased understanding of the physiology of preoperative and postoperative care has significantly raised the upper age limit for free-flap transfer in elderly patients. Despite pessimistic opinions regarding elderly patients who have poor recovery potential and decreased physiological reserves, the unique feature of free-tissue transfer is that it allows the transfer of well-vascularized tissue to defects in a single-stage procedure, and leads to improved quality of life. In this report, a retrospective analysis of 55 patients aged 50 and older who underwent microsurgical tissue transfer is presented. ⋯ In conclusion, if a patient's medical problems do not constitute a handicap, age itself should not be considered a barrier to free-flap transfer. It is important to be familiar with preoperative medical problems and possible postoperative medical complications in order to achieve a successful outcome. Contrary to what is generally suggested, surgical complications do not constitute a special consideration in older patients.