Application of Extradural Nerve Root Transfer in the Restoration of Lower Limb Function in Spinal Cord Injury

Study Design. Two fresh-frozen and six formalin-fixed cadavers were included in the study. Objective. To ascertain whether transferring T9 or T11 ventral root (VR) to L2 VR and T10 or T12 VR to L3 VR in restoring lower limb function after spinal cord injury is anatomically feasible. Summary of Background Data. Lower limb paralysis impairs the quality of the life and places burden on the whole society. However, no significant improvement in this area was achieved during recent years. Methods. In the present study, two fresh-frozen and six formalin-fixed cadavers were dissected to confirm the anatomical feasibility. A limited laminectomy was performed to expose the T9–L3 extradural nerve roots. T9 and T10 VR were anastomosed to L2 and L3 VR respectively, or T11 and T12 VR were anastomosed to L2 and L3 VR respectively. The pertinent distances between the donor and recipient nerves were measured and H&E staining was used to detect the axon number and cross-section area of each VR. Results. The limited incision was performed to expose the T9–L3 nerve root. According to the anatomic landmark of dorsal root ganglion, each VR could be isolated from each extradural nerve root. The T9 or T11 VR needs sural nerve graft to be transferred to L2 VR, and T10 or T12 VR also needs a nerve bridge to connect to L3 VR. The nerve numbers of T9, T10, T11, T12, L2, and L3 VRs and the sural nerves were measured respectively. The cross-section areas of T9, T10, T11, T12, L2, and L3 VRs and sural nerves were measured respectively. Conclusion. Our study suggested that application of transferring T9 or T11 VR to L2 VR and T10 or T12 VR to L3 VR in restoring lower limb function is anatomically feasible. Level of Evidence: 5