gms | German Medical Science

67th Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Korean Neurosurgical Society (KNS)

German Society of Neurosurgery (DGNC)

12 - 15 June 2016, Frankfurt am Main

Radiologic significance of ligamentum flavum hypertrophy as a major contributor for lumbar spinal canal stenosis

Meeting Abstract

Search Medline for

  • Joohyun Kim - Korea University Anam Hospital, Seoul, Korea
  • Junseok W. Hur - Korea University Anam Hospital, Seoul, Korea
  • Jang Bo Lee - Korea University Anam Hospital, Seoul, Korea
  • Tai Hyoung Cho - Korea University Anam Hospital, Seoul, Korea
  • Jung Yul Park - Korea University Anam Hospital, Seoul, Korea

Deutsche Gesellschaft für Neurochirurgie. 67. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), 1. Joint Meeting mit der Koreanischen Gesellschaft für Neurochirurgie (KNS). Frankfurt am Main, 12.-15.06.2016. Düsseldorf: German Medical Science GMS Publishing House; 2016. DocP 069

doi: 10.3205/16dgnc444, urn:nbn:de:0183-16dgnc4449

Published: June 8, 2016

© 2016 Kim et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at



Objective: Most common form of spinal stenosis is resulted from compression of neural structures by bulged disc, hypertrophy of the facet joints, and thickening of the ligamentum flavum (LF). Spinal stenosis is assessed commonly by radiologic measuring of dural sac cross-sectional area and great variation is observed between symptomatic and asymptomatic individuals. And, quantitative analysis for investigating major factors among them on lumbar spinal canal stenosis (LSCS) has not been examined yet. Purpose of this study is to investigate the effects of radiologic parameters in clinical outcomes. Representative factor on LF hypertrophic mechanism (hypetrophic factors) were also analyzed for evaluating a correlation on clinical outcomes.

Method: Two groups of patients with single level (L4-5) stenosis were studied retrospectively. The first group included 65 patients with severe claudication (SC, walking distance < 100 m) and the second, 35 patients without mild claudication (MC, walking distance = 100 m). Bulged disc area, LF area, LF thickness was measured on MRI, obtained from axial plane scan at the intervertebral disc level. Comparative analysis was carried out to evaluate the correlation among bulged area, LF area and thickness. Back pain, leg pain visual analogue scale (VAS), and severity of claudication were evaluated for clinical parameters. Hypertrophic factors (Vascular Endothelial Growth Factor [VEGF], Angiopoietin like protein II [ANPL2], Transforming Growth Factor beta 1 [TGFβ1], Fibroblast Growth Factor 1 [FGF1]) were analyzed with real-time reverse transcription PCR (RT-PCR) in the LF samples of 10 postoperative patients.

Results: Thecal sac area showed difference between two groups (SC: 72.08 ± 38.77 mm2, MC: 91.49 ± 36.48 mm2, P=0.042). LF area (SC: 149.52 ± 35.43 mm2, MC: 192.58 ± 38.48 mm2, P = 0.049) and thickness (SC: 5.81 ± 1.35 mm, MC: 4.66 ± 1.14 mm, P=0.037) were significantly larger in SC group. However bulged disc area showed no significant difference. LF area (OR = 1.23, CI: 1.04-1.46) and thickness (OR=4.017, CI: 1.29-12.53) also showed positive correlation with severity of claudication on logistic regression analysis. The hypertrophic factors showed no correlation with clinical parameters in correlation analysis. However, VEGF showed positive correlation with bulged disc area (r = 0.648, P < 0.043) and disc/canal ratio (r = 0.867, P < 0.001).

Conclusions: LF area and thickness compared to bulged disc were major contributor for claudication of LSCS in radiologic quantitative analysis. Furthermore VEGF-mediated angiogenesis known as functioning major step in LF hypertrophy pathogenesis might be correlated with disc bulging pathogenesis.