Clinical significance of redundant nerve roots of the cauda equina in lumbar spinal stenosis

Objectives The aim of this study was to evaluate the significance of redundant nerve roots (RNR) in lumbar stenosis by comparative analysis of a group of patients with RNR with a group without RNR. Patients and methods A total of 68 patients who underwent decompressive laminotomies for single-level lumbar stenosis were divided into two groups. Group I included patients with RNR, and group II included patients with no RNR (NRNR). RNR were defined as a tortuosity of elongated and coiled nerve roots in the subarachnoid space associated with spinal stenosis demonstrable by sagittal images of MRI. Comparative analysis was performed. Results RNR was found in 33.8% of patients with stenosis. Patients in the RNR groups were older than those in the NRNR group. There were no statistically significant differences between the two groups with regard to the duration of symptoms, preoperative and final Japanese Orthopaedic Associationʹs (JOA) scores, diameter of the spinal canal, recovery rate, and success rate of the surgery. However, the final JOA scores, recovery rate, and success rate showed a tendency to be better in the NRNR group. In the RNR group, the longer the relative length of RNR, the better the outcome. Conclusions RNR is a relatively common finding in association with spinal stenosis. It tends to develop in patients of more advanced age than patients with no RNR. Surgical outcomes in the RNR group were not statistically different from those in the NRNR group, although NRNR group showed slightly better outcomes.