title: Staged spinal cord decompression through posterior approach for thoracic myelopathy caused by ossification of posterior longitudinal ligament.
abstract: METHODS
  Prospective clinical study of the effect of staged elimination of anatomic factors inhibiting posterior shift of the thoracic spinal cord on the degree of posterior shift of the thoracic spinal cord and its significance in augmenting the safety of ossification of posterior longitudinal ligament (OPLL) manipulation in thoracic OPLL myelopathy.
  
  
  OBJECTIVE
  To develop a comprehensive method that enables safe and sufficient decompression of the spinal cord for thoracic OPLL myelopathy.
  
  
  BACKGROUND
  Decompression of the spinal cord by direct manipulations of thoracic OPLLs, via either anterior or posterior approach, caused some iatrogenic catastrophic spinal cord injuries, and methods to prevent such injuries during surgery have not yet been developed.
  
  
  METHODS
  Procedures of elimination of anatomic factors inhibiting posterior shift of the thoracic spinal cord were performed in stages at intervals of between 1 month and 11 years depending on patients' neurologic status. The first stage operation consisted of extensive cervicothoracic laminoplastic decompression with or without posterior longitudinal durotomy, and if the decompression were insufficient, measures for OPLL-spinal cord separation with or without OPLL manipulation were added.
  
  
  RESULTS
  All 17 patients with thoracic OPLL myelopathy showed improvements of neurology comparable with those with successful anterior approaches after decompression. The mean follow-up period was 42 months (range 6-101 months). Neurologic improvements persisted for the entire follow-up period in all patients except one patient who developed arachnoid cyst compressing the dorsum of the once-decompressed spinal cord 30 months after surgery.
  
  
  CONCLUSIONS
  Staged posterior decompression to eliminate anatomic factors inhibiting posterior shift of the thoracic spinal cord is the safest and the most reliable method of spinal cord decompression to treat thoracic OPLL myelopathy, so far. However, long-term results are required before the methods can be established.
authors.affiliation: Department of Orthopaedic Surgery, Saitama Medical Center, Saitama Medical School, Saitama, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Tsuzuki
authors.forename: S
authors.initials: S
authors.lastname: Hirabayashi
authors.forename: R
authors.initials: R
authors.lastname: Abe
authors.forename: K
authors.initials: K
authors.lastname: Saiki
mesh_terms: D000328:Adult; D000368:Aged; D019299:Decompression, Surgical / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D011446:Prospective Studies; D013117:Spinal Cord Compression / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000601:surgery*; D016896:Treatment Outcome