Microsurgery: Transplantation and Replantation by Harry J. Buncke, MD, et al.
  Table of Contents / Chapter 23:
Extensor Digitorum and Hallucis Brevis Muscle Transplantation and Application as an Island Muscle Flap
  The extensor digitorum brevis is invaluable in reconstructing problems in the distal third of the tibia, an area particularly difficult to cover with muscle flaps from the calf. These other alternatives have limited arcs of rotation, or have tenuous circulation when distally based. The extensor digitorum brevis has a large arc of rotation, including the distal anterior tibia and both malleoli,3,4,5 when it is freed as an island muscle flap. Fractures of the distal tibia and of the ankle can be resurfaced using the island muscle flap. The frequency with which open comminuted fractures occur in the distal tibia and the paucity of reconstructive options make this muscle a new and preferable choice. The excellent blood supply is useful in clearing these areas of infection in chronic wounds. Burns, radiation defects, and pressure ulcers of the foot and ankle are also amenable to the pedicled extensor digitorum brevis muscle reconstruction. Unfortunately, its small size limits its application.

Although the extensor digitorum brevis has received much attention as a method to reconstruct facial paralysis, 6-9,10-12,13-16 the long-term results have not been encouraging.5,16 The amount of muscle excursion does not provide an acceptable degree of facial animation. The serratus anterior muscle is superior for functional muscle transplantation in facial palsy reconstruction.

  Technical Considerations

Preoperative evaluation of the recipient site vasculature is essential in planning the free tissue transfer. Depending upon the clinical situation, angiography may be necessary to determine the recipient vessel. In other cases, noninvasive techniques such as the Doppler ultrasound probe will be adequate. It is especially important to establish the status of collateral circulation to the extremity because this will help in choosing the type of anastomosis. The blood supply to the donor foot can also be visualized preoperatively.

The nutrient artery of the extensor digitorum brevis muscle is the lateral tarsal artery, a branch of the dorsalis pedis artery that originates from the dorsalis pedis at the lower border of the extensor retinaculum. Because the caliber of the lateral tarsal artery is small, the muscle is raised with the lateral tarsal artery and the dorsalis pedis artery. The dorsalis pedis artery is used for microvascular anastomoses and also provides the vascular leash for pedicled muscle flap applications.

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