SLR - May 2023 - Lindsay Wynn
Title: A Retrospective Case Series on Free Flap Reconstruction for Ischemic Diabetic Foot: The Nutrient Flap Further ExplainedReference: Kwon JG, Cho MJ, Pak CJ, Suh HP, Hong JP. A Retrospective Case Series on Free Flap Reconstruction for Ischemic Diabetic Foot: The Nutrient Flap Further Explained. Plast Reconstr Surg. 2022 Jun 1;149(6):1452-1461.
Level of Evidence: Level III
Scientific Literature Review
Reviewed By: Lindsay Wynn
Residency Program: University of Florida College of Medicine-Jacksonville, Jacksonville, FL
Podiatric Relevance: With ischemic diabetic feet being difficult to salvage, this article offers an option that was otherwise seen as contraindicated. If a free flap is used as a nutrient flap on the ischemic diabetic foot, then there will be an increase in tissue oxygen content to the surrounding ischemic tissue which would reduce wound complications and need for major amputation.
Methods: This is a retrospective case series from a single surgeon at Asan Medical Center from August 2014 to July 2015. The patients were divided into two groups: group 1 underwent free flap reconstruction, and group 2 underwent partial foot amputation with primary closure/local flap. All patients with ischemic diabetic foot wounds underwent preoperative percutaneous transluminal angioplasty to revascularize the angiosome that contained the wound. If the tissue surrounding the defect was less than 40mmHg, the patient underwent hyperbaric oxygen therapy. Both groups underwent debridement prior to their respective closure. The primary outcome measure was incidence of complete or partial flap loss evaluated by subjective flap evaluation and use of near-infrared perfusion scans. The secondary outcome measures were duration until complete healing was obtained and need for additional debridement after the reconstruction.
Results: In the free flap group, total flap loss occurred in one patient who underwent a second free flap 6 days after the initial operation. Partial flap loss occurred in four patients (10.5%); two patients healed with secondary intention, and two patients required higher-level amputations. One patient had a below-knee amputation because of osteomyelitis 16 months after a successful free flap. Total of 3 patients (8%) required secondary below-knee amputation. The number of debridement’s required for the non-free flap group was significantly higher than that for the free flap group. The mean length for wound healing was not statistically significant between the two groups. At 6-months postoperative follow-up, the mean transcutaneous partial pressure of oxygen level was statistically higher in group 1 (61.6 ± 7.5mmHg) than in group 2 (32.6 ± 5.8mmHg).
Conclusions: The authors concluded that the patients who underwent free flap reconstruction had higher transcutaneous partial pressure of oxygen level, fewer postoperative wound-healing complications, and fewer major amputations compared to the local flap or primary closure group. They evaluated a follow-up angiogram in a few patients with the free flap reconstruction and could see the formation of angiogenesis on the ischemic foot coming from the flap. An important takeaway is the rigorous vascular testing and hyperbaric oxygen therapy performed prior to either reconstruction method. This is crucial to optimize the wound site prior to reconstruction. But with the free flap it seemed to keep the transcutaneous oxygen pressures higher for a longer period of time after revascularization which allows more time for the foot to fully heal. The main limitation to this study is only 6 patients had postoperative angiographic patency data whereas the other patients were measured by transcutaneous partial pressure of oxygen level which is an indirect assessment.