Transfer of Sciatic Nerve Motor Branches in High Femoral Nerve Injury: A Cadaver Feasibility Study and Clinical Case Report

BACKGROUND Femoral nerve injury causes knee dysfunction, and high femoral nerve injury is difficult to repair. OBJECTIVE To evaluate the anatomic feasibility of transferring the sciatic nerve motor branches in high femoral nerve injury. METHODS The femoral nerve was exposed in both lower extremities of 3 adult fresh-frozen cadavers; each branch was noninvasively dissected to its proximal nerve fiber intersection point and distal muscle entry point. The branches of the sciatic nerve were also exposed. The length, diameter, and number of myelinated fibers were measured in each femoral and sciatic nerve branch. The feasibility of tension-free direct suture between the femoral and sciatic nerve branches was evaluated. One patient was treated with transfer of a nerve branch innervating the semitendinosus muscle to the femoral nerve branch and was followed up for 18 mo. RESULTS The diameters and numbers of myelinated fibers in the femoral nerve branches matched those of the sciatic nerve branches. In the single patient, a combined femoral nerve bundle (comprising the rectus femoris and vastus lateralis branches) was used as a graft. The branch of the sciatic nerve was sutured with the muscle branch of the femoral by using a sural nerve as a nerve graft. The knee joint straightening strength reached medical research council grade 4+. CONCLUSION The proximal motor branches of the sciatic nerve may be transferred as donor nerves to repair high femoral nerve injury. A femoral nerve bundle comprising the rectus femoris and vastus lateralis branches may be used as the receptor nerve.