Discussion: Reconstruction of the Heel, Middle Foot Sole, and Plantar Forefoot with the Medial Plantar Artery Perforator Flap
The authors do not elaborate on the dissection of the medial plantar artery perforator flap, and thus some confusion may exist regarding the exact nature of the flap that they use. Let me begin by removing any confusion that might exist regarding nomenclature. The authors refer to the flap as a medial plantar artery perforator flap. The plantar fascia is not included in the flap and, I suspect, though it is not clear, that the medial plantar artery is not routinely transected when raising the flap; rather, the flaps are “propellered” based on the perforator(s) vessel(s) that are dissected. This differentiates this flap from the medial plantar artery flap that first appeared in our literature in 1979.1 The anatomical basis for the medial plantar artery perforator flap variant has been described by Koshima et al.2 The other bit of confusion that can arise pertains to the term “medialis pedis flap,” which will often appear when one searches for anatomical descriptions of flaps from the instep region. The medialis pedis flap comprises the thin skin and subcutaneous tissue that is in a different location than the medial plantar flap or the medial plantar artery perforator flap, as the tissue comes from the most medial aspect of the foot, medial to the medial plantar artery perforator or medial plantar flap. It is nourished by a lateral branch of the deep medial plantar artery, which arises from the medial plantar artery near its origin from the posterior tibial artery within the tarsal tunnel.3 It is the superficial branch of the medial plantar artery that provides the blood supply to the medial plantar flap and the perforators associated with the medial plantar artery perforator flap. Also, the literature uses the terms “instep flap” and “medial plantar flap” interchangeably, as these flaps are one and the same. In the Discussion section of this article, the authors mistakenly describe the “instep flap” as being supplied by the deep branch of the medial plantar artery, and this is both confusing and wrong.
It is important to realize that when the literature refers to the medial plantar artery, it is referring to the superficial branch of the medial plantar artery, and these terms are used interchangeably. In one anatomical study of 26 fresh cadaver feet, the superficial branch of the medial plantar artery was present in all dissections.4 As the vascular anatomy on the sole of the foot is consistent, I agree with the authors that in the well-vascularized patient all that is required is assessment of the donor site with the hand-held Doppler probe. It is important to always occlude the dorsalis pedis artery when listening to the medial plantar artery (or its perforators) to make certain that the blood flow is antegrade from the proximal medial plantar artery. Although this would not necessarily affect the outcome from a true perforator flap, if the medial plantar artery requires ligation, the direction of blood flow in the flap is crucial.