Effects of dimethylthiourea, melatonin, and hyperbaric oxygen therapy on the survival of reimplanted rabbit auricular composite grafts.

Abstract

Microvascular reconstruction currently offers the best chance of survival for an ear segment reimplanted after amputation. Unfortunately, this technique is possible only when ear and scalp vessels remain intact. Direct reattachment of the amputated segment as a composite graft is less reliable because survival is poor for grafts larger than 2 cm in diameter. However, if survival could be improved, direct reattachment would be an attractive alternative in situations in which microsurgical revascularization is not possible. Certain pharmacologic agents have been shown to enhance the survival of composite grafts. This study demonstrated that hyperbaric oxygen, dimethylthiourea, and melatonin significantly affected the survival of reimplanted auricular composite grafts at day 7. However, by day 21 the average percentage of survival for all groups approached 13% to 14%. Dimethylthiourea had the most beneficial effect on survival early in the postoperative period, whereas the hyperbaric oxygen group demonstrated the poorest survival.