Cauda equina redundant nerve roots are associated to the degree of spinal stenosis and to spondylolisthesis

Associação entre a presença de raízes redundantes na cauda equina e a área seccional do saco dural avaliada por meio de ressonância magnética

To evaluate the association of redundant nerve roots of cauda equina (RNRCE) with the degree of lumbar spinal stenosis (LSS) and with spondylolisthesis.

Method

After Institutional Board approval, 171 consecutive patients were retrospectively enrolled, 105 LSS patients and 66 patients without stenosis. The dural sac cross-sectional area (CSA) was measured on T2w axial MRI at the level of L2-3, L3-4 and L4-5 intervertebral discs. Two blinded radiologists classified cases as exhibiting or not RNRCE in MRI. Intra- and inter-observer reproducibility was assessed.

Results

RNRCE were associated with LSS. RRNCE was more frequent when maximum stenosis<55 mm². Substantial intra- observer agreement and moderate inter-observer agreement were obtained in the classification of RNRCE. Spondylolisthesis was identified in 27 patients and represented increased risk for RRNCE.

Conclusion

LSS is a risk factor for RNRCE, especially for dural sac CSA<55 mm². LSS and spondylolisthesis are independent risk factors for RNRCE.

magnetic resonance imaging; spinal nerve roots; cauda equina; spinal stenosis; spondylolisthesis