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

Abstract

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 mm 2 . 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 mm 2 . LSS and spondylolisthesis are independent risk factors for RNRCE.Keywords: magnetic resonance imaging, spinal nerve roots, cauda equina, spinal stenosis, spondylolisthesis. RESUMOAvaliar associação entre raízes nervosas redundantes da cauda eqüina (RNRCE) com grau de estenose do canal lombar (ECL) e espondilolistese. Método: Após aprovação do Comitê de Ética, 171 pacientes foram selecionados retrospectivamente, 105 com ECL e 66 sem estenose. Foram realizadas mensurações da área seccional do saco dural em imagens axiais de RM ponderadas em T2 em L2/L3, L3/L4 e L4/ L5. Presença ou não de RRNCE foi classificada de forma independente por dois radiologistas, às cegas. Concordância intra e inter-observador foi analisada. Resultados: RNRCE foi associada à ECL e foi mais freqüente quando a máxima estenose encontrada foi ,55mm 2. Houve grande concordância intra-observador e moderada inter-observador na classificação das RRNCE. Espondilolistese foi identificada em 27 pacientes e representou maior risco para desenvolvimento de RNRCE. Conclusão: ECL é fator de risco para RNRCE, especialmente com áreas seccionais ,55mm 2. ECL e espondilolistese representam fatores de risco independentes para desenvolvimento de RNRCE.Palavras-chave: ressonância magnética, raizes nervosas, cauda equina, estenose espinhal, espondilolistese.Redundant nerve roots of the cauda equina (RNRCE) are characterised in magnetic resonance images (MRIs) of the lumbosacral spinal cord by the presence of elongated and tortuous nerve roots with a serpiginous or coiled appearance and near an area of spinal canal stenosis 1,2,3,4,5,6,7,8 . The literature describes this entity in association with degenerative spinal canal stenosis (Figure 1). It is believed that the acquired elongation of the nerve roots is due to a chronic compression force at the level of the lumbar spinal stenosis (LSS) 9 . This condition is not a new or separate disease but may be part of the natural evolution of lumbar canal stenosis.The recognition of RNRCE in diagnostic imaging is especially important for avoiding the misdiagnosis of other dis...

Redundant nerve roots in lumbar spinal stenosis: inter- and intra-rater reliability of an MRI-based classification

“…1). In the remaining 40% of patients, redundant nerve roots (RNRs) of the cauda equina are evident on preoperative magnetic resonance images (MRIs) [2][3][4][5]. RNRs were first described by Verbiest [6] in 1954, and they were named 14 years later by Cressman and Pawl [7].…”

Electrodiagnostic characteristics of upper lumbar stenosis: Discrepancy between neurological and structural levels

“…The reported prevalence of RNRs in patients with lumbar spinal canal stenosis varied from 15% to 42% . The prevalence of RNRs in patients without spinal canal stenosis was reported as 9%, which is significantly lower than that in patients with spinal stenosis (41%) . Furthermore, the severity of lumbar spinal canal stenosis was demonstrated as a risk factor for RNRs .…”

“…The prevalence of RNRs in patients without spinal canal stenosis was reported as 9%, which is significantly lower than that in patients with spinal stenosis (41%) . Furthermore, the severity of lumbar spinal canal stenosis was demonstrated as a risk factor for RNRs . The pathogenesis of RNRs is still unclear, and it has been suggested that RNRs are associated with damaged nerve roots and impaired nerve–blood barrier resulting from spinal canal constriction .…”

Redundant Nerve Root in a Patient With Chronic Lumbar Degenerative Canal Stenosis

“…1,2 Redundant nerve root is a complication that arises as a result of continuous and chronic compressive forces on the nerve roots within the canal of a CLDCS. Chronic lumbar degenerative canal stenosis is the result of degenerative narrowing of the lumbar spinal canal caused by bulging of an intervertebral disk, osseous hypertrophy of the vertebral neural arch, apophyseal joint arthrosis, ligamentum flavum hypertrophy, and/or degenerative spondylolisthesis.…”

“…The reported prevalence of RNR varies, with some observing it in 33.8% to 42% of patients with CLDCS. 1 There is no statistical gender difference for RNR. 7 The purpose of this case study was to present the diagnostic imaging findings of a patient with CLDCS with associated redundant nerve roots.…”