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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

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Usefulness of three-dimensional measurement of ossification of the posterior longitudinal ligament in patients with induced myelopathy

Meeting Abstract

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  • Nam Lee - Yonsei University College of Medicine, Severance Hospital
  • Gyu Yeul Ji - Yonsei University College of Medicine, Severance Hospital
  • Hyun Chul Shin - Kangbuk Samsung Hospital
  • Yoon Ha - Yonsei University College of Medicine, Severance Hospital
  • Dong Ah Shin - Yonsei University College of Medicine, Severance Hospital

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. DocDI.05.09

doi: 10.3205/16dgnc126, urn:nbn:de:0183-16dgnc1267

Published: June 8, 2016

© 2016 Lee et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

Outline

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Objective: Posterior longitudinal ligament (OPLL) is not a two-dimensional (2D) disease, but rather a three-dimensional (3D) disease. Therefore, conventional measurement of parameters using radiography may not be suitable for evaluating OPLL. However, there is no study investigated the correlation between 3D parameters of OPLL and clinical outcomes. Therefore, the aim of this study is to evaluate the usefulness of three-dimensional (3D) measurement of ossification of the posterior longitudinal ligament (OPLL), and identify the reliability of a novel 3D method of measurement.

Method: Fifty patients (40 males and 10 females; mean age 57.2 years) with symptomatic OPLL were enrolled. Neurological and clinical outcome scales were measured using the Japanese Orthopedic Association (JOA) score, visual analogue scale (VAS), short-form health survey (SF-36) and neck disability index (NDI). A 3D model was reconstructed with DICOM files from axial CT images using software (MIMICS®; Materialise, Leuven, Belgium) to obtain the following parameters: 3D volume of OPLL (amount of whole volume of OPLL), 3D volume of the spinal canal (confined to the vertebral level involving OPLL), spinal canal diameter (anterior-posterior interval of spinal canal), thickness of OPLL (anterior-posterior interval of OPLL), and length of OPLL (longitudinal interval of OPLL). All patients were divided into two different groups, the mild myelopathy group (JOA score = 18, n = 11) and the severe myelopathy group (JOA score = 17, n = 23).

Results: The 3D OPLL volume itself did not correlate with clinical outcomes (r = -0.275, P = 0.116). 3D OPLL ratio and OPLL thickness had a significant negative relationship with JOA score (r = -0.502, P < 0.005 and r = -0.437, P < 0.05, respectively). In particular, 3D OPLL ratio was an independent risk factor for increased severity of myelopathy (B = -29.71, P < 0.05). On the other hand, conventional occupying ratio did not show statistical significance (r = -0.293, P = 0.093). The mild myelopathy group showed lower 3D OPLL ratio than the severe myelopathy group (0.092 vs. 0.148, P < 0.05).

Conclusions: 3D method of measurement is superior to the conventional method in terms of evaluating the clinical state of symptomatic OPLL patients. Higher 3D OPLL ratio has an adverse effect on the spinal cord and is associated with deteriorating JOA score.