Anatomical feasibility of transferring the obturator and genitofemoral nerves to repair lumbosacral plexus nerve root avulsion injuries.

Nerve transfer is a valid surgical procedure for restoring lower-extremity function after lumbosacral plexus nerve root avulsion. We determined the anatomical feasibility of transferring the obturator and genitofemoral nerves for this purpose. The obturator, genitofemoral and femoral nerves, and the S1 and S2 nerve roots on both sides were exposed in 10 cadaver specimens. We traced all nerves to their origins. The lengths of the obturator and genitofemoral nerves were measured from their origins to their exits from the abdominal cavity. The transverse and longitudinal diameters of all nerves were measured. Specimens were obtained to determine the total number of myelinated fibers in each nerve. The proximal part of the left obturator nerve was anastomosed with the distal part of the right femoral nerve, between the vertebrae and the peritoneum, with an overlap of 2-3 cm. Similarly, the proximal parts of the right obturator and genitofemoral nerves were anastomosed with the ipsilateral S1 and S2 nerve roots, respectively, with an overlap of 2-4 cm. The obturator nerve contained approximately one-third of the number of fibers (4,300-7,800) presenting in the femoral nerve (13,500-21,000). Similarly, the number of fibers found in the S1 nerve root was in the range 5,200-8,900. The genitofemoral nerve contained approximately half the number of fibers (3,000-4,500) presenting in the S2 nerve root (4,600-8,400). The obturator and genitofemoral nerves could be suitable donor nerves for repairing lumbosacral plexus nerve root avulsion.