title: Radiological significance of ligamentum flavum hypertrophy in the occurrence of redundant nerve roots of central lumbar spinal stenosis.
abstract: OBJECTIVE
  There were previous reports of redundant nerve roots (RNRs) focused on their clinical significance and pathogenesis. In this study, we investigated the significant radiologic findings that correlate with RNRs occurrence. These relations would provide an advanced clue for clinical significance and pathogenesis of RNRs.
  
  
  METHODS
  Retrospective research was performed with data from 126 patients who underwent surgery for central lumbar spinal stenosis (LSS). Finally, 106 patients with common denominators (inter-observer accuracy : 84%) were included on this study. We divided the patients into two groups by MRI, patients with RNRs and those with no RNRs (NRNRs). Comparative analyses were performed with clinical and radiologic parameters.
  
  
  RESULTS
  RNRs were found in 45 patients (42%) with central LSS. There were no statistically significant differences between the two groups in severity of symptoms. On the other hand, we found statistically significant differences in duration of symptom and number of level included (p<0.05). In the maximal stenotic level, ligamentum flavum (LF) thickness, LF cross-sectional area (CSA), dural sac CSA, and segmental angulation are significantly different in RNRs group compared to NRNRs group (p<0.05).
  
  
  CONCLUSIONS
  RNRs patients showed clinically longer duration of symptoms and multiple levels included. We also confirmed that wide segmental angulation and LF hypertrophy play a major role of the development of RNRs in central LSS. Together, our results suggest that wide motion in long period contribute to LF hypertrophy, and it might be the key factor of RNRs formation in central LSS.
authors.affiliation: Department of Neurosurgery, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Junseok W
authors.initials: JW
authors.lastname: Hur
authors.forename: Junho K
authors.initials: JK
authors.lastname: Hur
authors.forename: Taek-Hyun
authors.initials: TH
authors.lastname: Kwon
authors.forename: Youn Kwan
authors.initials: YK
authors.lastname: Park
authors.forename: Hung Seob
authors.initials: HS
authors.lastname: Chung
authors.forename: Joo Han
authors.initials: JH
authors.lastname: Kim
keywords: Central lumbar spinal stenosis; Ligamentum flavum hypertrophy; Redundant nerve roots