A Systematic Review of Classification Systems for Cervical Ossification of the Posterior Longitudinal Ligament

Lindsay Tetreault, Hiroaki Nakashima, So Kato, Michael Kryshtalskyj, Narihito Nagoshi, Aria Nouri, Anoushka Singh, Michael G. Fehlings

Research output: Contribution to journalReview article

2 Citations (Scopus)

Abstract

Design: Systematic review. Objective: To conduct a systematic review to (1) summarize various classification systems used to describe cervical ossification of the posterior longitudinal ligament (OPLL) and (2) evaluate the diagnostic accuracy of various imaging modalities and the reliability of these classification systems. Methods: A search was performed to identify studies that used a classification system to categorize patients with OPLL. Furthermore, studies were included if they reported the diagnostic accuracy of various imaging modalities or the reliability of a classification system. Results: A total of 167 studies were deemed relevant. Five classification systems were developed based on X-ray: the 9-classification system (0.60%); continuous, segmental, mixed, localized or focal, circumscribed and others (92.81%); hook, staple, bridge, and total types (2.40%); distribution of OPLL (2.40%); and K-line classification (4.19%). Six methods were based on computed tomography scans: free-type, contiguous-type, and broken sign (0.60%); hill-, plateau-, square-, mushroom-, irregular-, or round-shaped (5.99%); rectangular, oval, triangular, or pedunculate (1.20%); centralized or laterally deviated (1.80%); plank-, spindle-, or rod-shaped (0.60%); and rule of nine (0.60%). Classification systems based on 3-dimensional computed tomography were bridging and nonbridging (1.20%) and flat, irregular, and localized (0.60%). A single classification system was based on magnetic resonance imaging: triangular, teardrop, or boomerang. Finally, a variation of methods was used to classify OPLL associated with the dura mater (4.19%). Conclusions: The most common method of classification was that proposed by the Japanese Ministry of Health, Labour and Welfare. Other important methods include K-line (+/−), signs of dural ossification, and patterns of distribution.

Original languageEnglish
Pages (from-to)85-103
Number of pages19
JournalGlobal Spine Journal
Volume9
Issue number1
DOIs
Publication statusPublished - 2019 Feb 1

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Keywords

  • classification systems
  • dural ossification
  • K-line classification
  • ossification of the posterior longitudinal ligament
  • reliability

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine
  • Clinical Neurology

Cite this

Tetreault, L., Nakashima, H., Kato, S., Kryshtalskyj, M., Nagoshi, N., Nouri, A., Singh, A., & Fehlings, M. G. (2019). A Systematic Review of Classification Systems for Cervical Ossification of the Posterior Longitudinal Ligament. Global Spine Journal, 9(1), 85-103. https://doi.org/10.1177/2192568217720421