SLR - December 2020 - Cody R. Ingram

Free-Flap Reconstruction for Diabetic Lower Extremity Limb Salvage

Reference: Lee Z, Daar DA, Stranix JT, Anzai L, Levine JP, Saadeh PB, and Thanik VD, Free-Flap Reconstruction for Diabetic Lower Extremity Limb Salvage. J Surg Res. 2020 April (248) 165-170.

Level of Evidence: Level 3

Scientific Literature Review

Reviewed By: Cody R. Ingram, DPM, MPH
Residency Program: McLaren Oakland Hospital – Pontiac, MI

Podiatric Relevance: The armamentarium of any podiatric surgeon who manages complex wounds should include a vast knowledge of limb salvage. Diabetic patients with significant tissue loss, especially those with uncontrolled hyperglycemia, are often confronted with few options for limb preservation. However, the emerging arena of orthoplastics brings the potential for greater positive outcomes. Microsurgical free-flap tissue transfer in particular is useful in the setting of exposed hardware, wound complications, and refractory diabetic wounds.  This level III retrospective study evaluated 806 lower extremity free-flap reconstructions. A total of 33 free flaps were used for coverage of nonhealing lower-extremity diabetic ulcers. The primary outcomes were flap survival and wound complications.

Methods:  The records of a Level-I trauma center were reviewed from 1979-2016 to find 33 cases of free flaps utilized in the coverage of nonhealing lower-extremity diabetic ulcers. Recipient site characteristics included: location of wound and vessel runoff (defined both as normal versus abnormal and as one, two or three vessels identified on angiography or vascular imaging). Additionally, operative characteristics included: revascularization (ie- angioplasty, stenting, or bypass), whether or not revascularization was performed before or at the time of flap coverage, flap category (muscle versus fasciocutaneous flap), specific flap type, flap size, vessel size, type of vessel anastomosis (end-to-side [E-S] versus end-to-end [E-E]), size mismatch between donor and recipient vessels, and the number of veins anastomosed. Flap failure was considered the primary perioperative outcome and was divided into total and partial flap failure.

Results: The overall success rate of microvascular reconstruction was 90.9 percent, as 30 flaps were successful. The flap salvage rate was 50 percent (6 flaps initially failed, three went on to total failure and three went on to heal with a return to the operating room). Comparison of comorbidities between patients with wound complications and patients without complications did not differ significantly. Surprisingly, medical comorbidities (being defined as coronary artery disease, peripheral vascular disease (PVD), end-stage renal disease, and tobacco use) was not found to be significantly associated with outcomes. E-S anastomosis was associated with a significantly lower risk of wound complications than an arterial E-E anastomosis (0 percent versus 45.5 percent, p < 0.001).

Conclusions: Microvascular reconstruction in diabetic lower extremity wounds is an excellent tool in selected patients as part of the limb salvage algorithm. Muscle-based flaps were used much more commonly in this study, which is in line with other meta-analyses. Furthermore, muscle flaps are associated with increased blood flow, which is particularly helpful in the setting of PAD, of which 50 percent of the study population suffered. This article reinforces the utility of free flaps in the management of tissue loss from diabetic foot ulcers. 

Educational Opportunities