Can Great Toe Pedicle Flaps Have An Impact For Complicated DFUs?
The anatomy of the dorsal and plantar circulation varies from patient to patient.2 Typically, the anatomy of the great toe consists of the first digital metatarsal artery from the dorsalis pedis artery or the plantar digital artery via the lateral plantar artery. Communicating branches from the dorsal and plantar system are by way of the pedal arch. The dorsalis pedis becomes the first interosseous artery and divides into the first and second metatarsal to communicate with the lateral plantar artery. The digital arteries can be less than 1 mm thick and visualization best occurs with loupe magnification.
Typically, the pivot point is at the common digital artery. However, in cases in which additional length is needed, one can trace the digital artery of the first web space to the dorsalis pedis artery after the first dorsal interosseous muscle divides to permit visualization. When arterial inflow is antegrade or one is planning to utilize the great toe pedicle flap as a free flap, the surgeon can further dissect the pedicle to the anterior tibial artery. Further discussion of the free flap is beyond the scope of this article.
The blood supply to the great toe depends on the arterial anastomosis of the medial plantar artery, lateral plantar artery or first dorsal metatarsal artery. If all of these vessels are patent, then all three supply flow to the great toe.
Occasionally, increased mobility is required for coverage of distal forefoot defects. One should also assess retrograde flow to the great toe. If one places the Doppler over the lateral plantar artery with occlusion of the dorsalis pedis artery and the signal is audible, this signifies antegrade flow from the posterior tibial artery to the lateral plantar artery.3 An inaudible signal at the lateral plantar artery represents retrograde flow from the dorsalis pedis artery. However, this flap variation is contraindicated when the plantar circulation is absent.
Detailed angiography can occur as part of the preoperative workup for flap design if the clinical scenario warrants further investigation. Multiple views of the foot are helpful for visualizing digital arteries, the presence or absence of dorsal-plantar communication, or any vascular anomalies. The dorsal venous network supplies an abundance of vascular choices for outflow.
Pertinent Considerations With Flap Design
One must thoroughly investigate both the recipient and donor sites. If infection is present, appropriate treatment is a major component that contributes to flap survivability. Antibiotic therapy can control bacterial load. Surgical debridement is necessary to remove any non-viable or infected tissue. Surgeons should properly prepare the wound and delay soft tissue reconstruction until all signs of inflammation and infection have resolved. When excising the plantar ulceration, the surgeon should do so with caution so as not to injure the metatarsal artery and its digital branch to the side of the toe donating the flap.
Some considerations in flap design include the size of the donor defect, the depth of the recipient defect and the amount of mobility required to achieve closure. This includes examining the size and depth of the recipient site along with the type of exposed tissue (subcutaneous tissue, muscle, tendon, capsule or bone). If deep structures are exposed, then the recipient wound base may require some granulation tissue formation. The condition and characteristics of the donor site are equally as important. The donor skin and tissue must be healthy to ensure flap take.