title: The cutoff value of ossification of posterior longitudinal ligament (OPLL) for early diagnosis of myelopathy using somatosensory evoked potential in cervical OPLL patients.
abstract: METHODS
  Retrospective study.
  
  
  OBJECTIVE
  The objective of this study was to find out whether ossification of posterior longitudinal ligament (OPLL) characteristics, including size, shape and subtype, can be used to diagnose myelopathy using somatosensory evoked potential (SEP) in cervical OPLL patients.
  
  
  METHODS
  Yonsei University College of Medicine, Seoul, Korea.
  
  
  METHODS
  We retrospectively reviewed the medical records of 153 cervical OPLL patients who underwent SEP study. OPLL anterior-posterior (AP) diameter, area and involved longitudinal vertebral level were measured. OPLL was classified into subtypes according to longitudinal continuity and shape. Correlation analysis and receiver operating curve were used.
  
  
  RESULTS
  Tibial SEP latency was significantly correlated with OPLL AP diameter (P=0.001), diameter occupying ratio (P=0.019), area (P=0.007), area occupying ratio (P=0.008), involved longitudinal vertebral level (P=0.028) and space available for the spinal cord (P=0.019). The cutoff values that were diagnostic for SEP prolongation suggesting myelopathy were 4.91 mm for OPLL AP diameter, 6.02 mm for space available for the spinal cord, 44.5% for diameter occupying ratio, 63.4 mm2for area, 36.1% for area occupying ratio and level 2 for the involved longitudinal vertebral level.
  
  
  CONCLUSIONS
  Our results revealed that tibial SEP latency was significantly correlated with OPLL size and suggested cutoff values of OPLL diameter (4.91 mm, 44.5%) and area (63.4 mm2, 36.1%) for early diagnosis of myelopathy. These results can help to establish treatment plans.
authors.affiliation: Department of Rehabilitation Medicine, Bundang Jesaeng General Hospital, Gyeonggi-do, Republic of Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Yoon
authors.affiliation: Department of Rehabilitation Medicine and Rehabilitation Institute of Neuromuscular Disease, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: T H
authors.initials: TH
authors.lastname: Park
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: N L
authors.initials: NL
authors.lastname: Eun
authors.affiliation: Department of Rehabilitation Medicine and Rehabilitation Institute of Neuromuscular Disease, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Y G
authors.initials: YG
authors.lastname: Park
mesh_terms: D042241:Early Diagnosis; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013116:Spinal Cord / Q000000981:diagnostic imaging; D013118:Spinal Cord Diseases / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D013979:Tibial Nerve / Q000503:physiopathology; D014057:Tomography, X-Ray Computed