RESUMEN
BACKGROUND: The sural nerve is the nerve most commonly used for peripheral nerve reconstruction. According to requirements for nerve graft length, it is dissected from the retromalleolar up to the popliteal region, where the main root of the sural nerve fibers, the medial sural cutaneous nerve, arises from the tibial nerve. It has been recommended to complete sural nerve harvesting below this area, to avoid damage to the tibial nerve. The aim of this study was to determine whether sural nerve fibers can be isolated from tibial and, more proximal, sciatic nerve fibers to gain more sural nerve graft length. METHODS: The sural nerve was dissected in 30 lower limbs. Anatomical characteristics such as the existence of a union forming the sural nerve, identification of the main root of sural nerve fibers, and the site of origin of the branch(es) forming the sural nerve were noted. Careful nerve preparation in the region of the sural nerve and its main root origin was conducted. RESULTS: In 18 specimens (60 percent), the authors found the classic formation of the sural nerve: the union of the medial sural cutaneous nerve and the peroneal communicating branch. The medial sural cutaneous nerve was the main root of sural nerve fibers in 28 of 30 cases (93 percent) and originated from the tibial nerve. Careful nerve preparation and epineurolysis beyond its anatomical origin allowed isolation and gain of sural nerve graft length of a median of 14 cm. CONCLUSION: In the authors' opinion, this is a feasible method of increasing the quantitative and qualitative outcome of sural nerve harvesting when greater length of sural nerve donor graft is needed for adequate nerve reconstruction.