|Microsurgery: Transplantation and Replantation by Harry J. Buncke, MD, et al.|
| Because the dorsalis pedis artery is transected in the elevation of the extensor digitorum brevis muscle, the foot must be assessed for the presence of the posterior tibial artery. The noninvasive method we use is the Doppler ultrasound probe. The dorsalis pedis artery is compressed at the level of the tarsal bones, and the first dorsal metatarsal artery, the continuation of the dorsalis pedis artery, is auscultated using a Doppler probe. An arterial wave form with proximal compression of the dorsalis pedis artery indicates collateral circulation in the foot. Compression of the posterior tibial artery at the medial malleolus following compression of the dorsalis pedis artery at the tarsal bones should lead to diminution of the arterial signal at the first dorsal metatarsal artery as detected by the Doppler probe. This further establishes the fact that the posterior tibial artery contributes to the collateral circulation to the foot. Absence of an arterial signal in the first dorsal metatarsal artery, or disappearance of a signal in the first dorsal metatarsal artery when the dorsalis pedis artery is blocked suggests that the dorsalis pedis artery may be the only vessel supplying the foot, in which case, using the extensor digitorum brevis muscle may deprive the foot of its remaining blood supply. The use of the Doppler probe and sequential compression of the dorsalis pedis and posterior tibial arteries may be varied to determine the patency of the pedal arch. If there is any question, an angiogram will evaluate the patency more precisely.
| The venae comitantes of the lateral tarsal artery join the paired venae comitantes of the dorsalis pedis artery. It should be noted that there are branches of the superficial venous system of the foot that do drain the extensor digitorum muscle. Preservation of these venous branches may provide additional venous outflow or flexibility in reaching recipient veins.
The motor nerve to the extensor digitorum brevis muscle branches from the deep peroneal nerve as it passes from the ankle to the foot. Use of the extensor digitorum brevis muscle as functional muscle requires preservation of this fascicle from its entrance into the muscle to its junction with the deep peroneal nerve. Obtaining more length requires an intraneural dissection to free this fascicle from the other fascicles of the deep peroneal nerve, using magnification and a fine razor knife.
The proximal dorsalis pedis artery and its venae comitantes are covered by the inferior extensor retinaculum. To provide more length proximally for either free tissue transfer or island muscle flap rotation, this inferior extensor retinaculum can be divided until an adequate pedicle is free.
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