Can The Extensor Digitorum Brevis Muscle Flap Help Salvage A Diabetic Limb With Osteomyelitis?
Then dissect the dorsalis pedis artery distally and proximally. Identify the lateral tarsal artery and any muscular branches extending from the dorsalis pedis artery to the extensor digitorum brevis muscle and elevate these arteries along with the muscle. Take caution not to damage these vessels supplying the extensor digitorum brevis muscle. Then dissect the origin of the muscle off the calcaneus and sinus tarsi and divide the tendons. One can incorporate the fascia to add area to the muscle flap size.
Ensure that there is adequate flow by clamping the dorsalis pedis artery. The flow should not be coming primarily from the peroneal artery. To confirm the presence of retrograde flow intraoperatively, one can block the dorsalis pedis artery proximal to the lateral tarsal artery with microvascular clamps. Then evaluate the adequacy of perfusion via retrograde flow to the flap.
After deeming that perfusion is acceptable, ligate the appropriate vessels. Ligate the dorsalis pedis artery proximal to where it starts to branch out to the extensor digitorum brevis muscle. Also ligate the medial tarsal artery and any accompanying paired venae comitantes.
The length of the pedicle, when it is based on the lateral tarsal artery, typically varies from 4.8 to 7 cm.14 Typically, the pivot point is 1 cm distal to the tarsometatarsal joint. However, if more length is required, ligate the deep plantar branch and retrograde flow then occurs through the first dorsal metatarsal artery. The arc of rotation allows for coverage of the hallux. Then perform primary closure of the donor incision. After transposition of the muscle flap, one can then apply a split-thickness skin graft or delay graft placement until further wound healing occurs.
Addressing Potential Limitations Of The Flap Procedure
The main limitations to this flap include limited muscle size and sacrifice of a major blood vessel. The muscle flap may not cover the entire defect. In situations in which the muscle is smaller than anticipated and cannot cover the vital structures, then a backup plan (perhaps a free flap for example) may be necessary. In the situation with a one vessel runoff to the foot, the flap may be unreliable and/or the donor site may not heal.
The extended, distally-based extensor digitorum brevis muscle flap may be an alternative limb salvage option in select cases for osteomyelitis of the hallux in patients with diabetes.
Dr. Belczyk is a Fellow of the American College of Foot and Ankle Surgeons, and is board certified in both foot surgery and reconstructive rearfoot/ankle surgery by the American Board of Podiatric Surgery. He is a consultant physician at the Amputation Prevention Center at Valley Presbyterian Hospital in Van Nuys, Calif.
Dr. Chan is a third-year resident at White Memorial Medical Center in Los Angeles.