Functional reconstruction of lower extremity nerve injuries

Peripheral nerve injuries (PNI) in the lower extremity are an uncommon but highly morbid condition. Recent advances in our understanding of nerve physiology and microsurgical techniques have inspired renewed faith in nerve surgery and sparked a creative renaissance in the tools, approaches, and reconstructive schemas available to surgeons in the management of lower extremity PNIs. In this article, we review the literature and provide a principles-based approach for the surgical management of lower extremity PNIs with an emphasis on techniques for functional reconstruction after complete nerve injury. General principles in management include early diagnosis with electrodiagnostics and imaging, early surgical exploration, and opting for nerve and tendon transfers when primary reconstruction of the injured nerve is unfavorable (e.g., delayed reconstruction, unavailability of proximal or distal nerve stumps, or long regenerative distance). The goal of functional reconstruction should be to restore independent gait, so understanding the roles of major neuromuscular units during the gait cycle informs the selection of donor nerves and tendons for transfer. Based on these principles and literature to date, specific algorithms for surgical management are presented for femoral, sciatic, tibial, and common peroneal nerves. We recognize limitations of the current literature, namely the predominance of case series evidence, and call for the accrual of more patient data in surgical management of PNIs.