Anatomic feasibility of intercostal-to-femoral and ulnar-to-sciatic nerve transfers for lower extremity neurotization after traumatic spinal cord injury.

Abstract

Traumatic spinal cord injury (SCI) is associated with functional morbidity and limited options for restoring lower extremity motor function. We explored the technical feasibility of intercostal-to-femoral and ulnar-to-sciatic nerve transfers as a potential approach to reinnervate the lower limb following SCI. A cadaveric anatomical feasibility study was performed using a fresh-frozen adult human specimen to evaluate two novel nerve transfer strategies: posterior intercostal-to-femoral and long-segment ulnar-to-sciatic nerve transfers. Dissections assessed the ability to achieve direct, tension-free coaptation without interposition nerve grafts. Intercostal nerves T8-T10 were successfully harvested, mobilized, and tunneled to the proximal femoral nerve, demonstrating >2 cm overlap sufficient for tension-free coaptation. Similarly, long-segment ulnar nerve harvest from the hypothenar region to axilla enabled subcutaneous tunneling to the gluteal region and direct end-to-end coaptation with the sciatic nerve with >2 cm overlap and without the need for grafting. Both nerve transfer techniques avoided excessive tension at the coaptation sites. These findings establish the anatomic feasibility of intercostal-to-femoral and ulnar-to-sciatic nerve transfers and provide a practical anatomic foundation for future translational studies aimed at restoring lower extremity function in patients with SCI.