PURPOSE The traditional sural nerve biopsy is performed through a distal incision at or just above the ankle. Although a simple procedure, these biopsies are associated with significant morbidity. The authors review the anatomy of the sural nerve, previously described biopsy techniques, and potential complications. A more proximal approach and its outcomes are described. METHOD In the modified sural nerve biopsy a longitudinal incision is marked starting approximately 10 cm below the popliteal crease along the midline axis of the posterior calf mass. After induction of general anesthesia a tourniquet is placed on the thigh and set to 100mm Hg over systolic pressure. The skin and fascia are incised, allowing identification of the lesser saphenous vein and the adjacent medial sural nerve. A 2-3 cm segment is excised and submitted to pathology. Following this the proximal stump of the nerve is implanted into the gastrocnemius muscle. If a muscle biopsy is required it is harvested from the gastrocnemius at this time. Total operative time for the combined procedures is typically 20 minutes. A retrospective chart review was conducted of nine patients treated by the senior author with the modified sural nerve biopsy and sixteen patients who had been referred to the senior author after developing complications after the traditional distal biopsy by other surgeons. Outcomes were evaluated based on preservation of sensation and possible complications. RESULTS Of the nine patients operated on by the senior author with the modified sural nerve biopsy technique three reported diminished sensation over the dorsolateral aspect of the foot. No patients developed wound complications. As of the time of submission no patients from this series has developed a neuroma. Sixteen patients were seen in consultation by the senior author for evaluation of postoperative complications after traditional sural nerve biopsy by other surgeons. The patients in this group all reported diminished or absent sensation or numbness in the distribution of the sural nerve along the dorsolateral foot. Those patients presenting with wounds were treated successfully using standard wound regimens. Patients presenting with neuromas had excision and implantation of nerve to muscle. CONCLUSION The main benefit of this modified technique for biopsy of the sural nerve is that it requires the sacrifice of only one branch of the sural nerve. Whereas the traditional method involved biopsy of the common sural nerve, the present modification results in preservation of sensation provided by the remaining branch of the sural nerve. Another advantage is the ease in which a surgeon can perform a muscle biopsy with the more proximal incision. This yields faster operative time with potentially less morbidity. The presence of muscle in the same plane also allows the surgeon to bury the cut proximal end of the sural nerve, minimizing the risk of developing a painful neuroma. Finally, it is possible that a more proximally placed incision may result in a lower incidence of infection and dehiscence given a better blood supply and more supple and mobile soft tissues of the proximal leg relative to the distal leg. It is hoped that further experience with the technique will demonstrate a significant reduction in postoperative morbidity.