Cadaveric Atlas: Reverse Sural Flap Delayed Technique, A Novelty Approach to Stepwise Algorithm Utilizing Skin Substitute Bilayer

Abstract

Indications The most common location for transposition of the reverse sural flap is to the posterior heel and distal lateral malleolus. However, this flap's versatility allows for the limits of its indications to be increased to include multiple areas of the posterior lower limb with small defects. Much of the literature has provided a discussion of noted reasons to undergo the harvest of the reverse sural flap which include traumatic injuries with soft tissue deficient, severe infections including osteomyelitis which requires both bone and soft tissue resection, failed surgical incisions, tumor resection and for defects to the posterior lower limb that are not amenable for treatment with a more common flap technique. Furthermore, the flap offers the surgeon an alternative to a free tissue transfer and low donor site morbidity. Completing a delayed harvesting technique, the flap is raised over a period of days to weeks insuring the viability of the tissue and may help to produce more successful outcomes that are also more reproducible by many different surgeons. The purpose of the delay technique is to improve vascularity and venous outflow to the pedicle prior to acute transposition. Contraindications Although the reverse sural flap has continued to gain popularity and utilization, its list of complete and relative contraindications to attempting harvest remain present. Complete contraindications are limited but include significant poor circulation, inability to reach the defect site given its arc of rotation of the flap, to large of a tissue deficit and if another flap with better indication can be utilized. Relative contraindications continue to evolve as modifications to the technique improve functionality. Relative contraindications for the reverse sural flap have included patients with one or several of the following comorbidities: history of smoking, current smoker, obesity, diabetes, peripheral vascular disease, venous insufficiency/venous outflow disease and old age [1, 2, 3]. Older literature suggests up to 36% complication rate in these patient populations [1]. More recently, this data was supported further, identifying statistically significant increases in both major and minor reverse sural flap complications in patients with one or multiple noted comorbidities when compared to patients with no comorbidities. Smoking alone was noted to be the most significant independent risk factor for flap necrosis and ultimate failure [4]. One other relative contraindication is in those patients that are extremely high risk for limb loss. In these scenarios, alternative options must be contemplated by the surgeon as a posterior gastrocnemius flap would be required should a below knee amputation be indicated. In higher risk patient populations, a delayed technique for harvesting of the graft should be considered.