Synthetic nerve guide implants in humans: A comprehensive survey

OBJECTIVE: Lesions of the peripheral nervous system result in the loss of sensory and motor function and may in addition be accompanied by severe neuropathic syndromes originating from aberrant axonal regrowth. The transplantation of autologous nerve grafts represents the current "gold standard" during reconstructive surgery, despite obvious side effects. Depending on the demands of the lesion site, various donor nerves may be used for grafting (e.g., the sural, saphenous), sacrificing native functions in their target areas. Recently, several synthetic nerve guide implants have been introduced and approved for clinical use to replace autologous transplants. This alternative therapy is based on pioneering studies with experimental nerve guides. METHODS: We present a comprehensive review of all published human studies involving synthetic nerve guides. RESULTS: Data from some 300 patients suggest that for short nerve defects of a few centimeters, resorbable implants provide promising results, whereas a number of late compression syndromes have been documented for nonresorbable implants. CONCLUSIONS: To treat longer defects, further implant development is needed, a goal that could be achieved, for example, by more closely imitating the intact nerve architecture and regulatory cell-cell interactions.