title: Intraoperative 3-dimensional navigation and ultrasonography during posterior decompression with instrumented fusion for ossification of the posterior longitudinal ligament in the thoracic spine.
abstract: METHODS
  A retrospective clinical study was conducted.
  
  
  OBJECTIVE
  The purpose of this study was to describe the clinical outcomes of intraoperative 3D navigation (ITN) and ultrasonography during posterior decompression and instrumented fusion for thoracic myelopathy due to ossification of the posterior longitudinal ligament (OPLL).
  
  
  BACKGROUND
  The symptoms caused by thoracic-ossification of the posterior longitudinal ligament (T-OPLL) are usually progressive and do not respond to conservative treatment-surgical intervention is the only effective treatment option. Various methods have been described for the treatment of symptomatic T-OPLL, all of which have limitations.
  
  
  METHODS
  The study included 18 patients with T-OPLL who underwent posterior decompression with instrumented fusion from 2006 to 2011. A staged operative procedure was used. First, pedicle screws were placed with ITN and a wide laminectomy was performed with resection of ossification of the ligamentum flavum (if present). With insufficient decompression on intraoperative ultrasonography, additional circumferential decompression was performed through a transpedicular approach. ITN-guided OPLL resection was performed using a burr attached to a navigational tracker. In all cases, posterior instrumented fusion was performed in situ. The outcomes were evaluated with the modified Japanese Orthopaedic Association scores and recovery rates.
  
  
  RESULTS
  Intraoperative ultrasonography showed that posterior laminectomy was sufficient in 6 patients; the remaining 12 were treated with additional circumferential decompression. The follow-up period ranged from 1 to 6 years (mean period, 2.8 y). Postoperative transient neurological deterioration occurred in 1 patient, and cerebrospinal fluid leakage occurred in 4 patients. All patients showed neurological recovery with a mean Japanese Orthopaedic Association score that improved from 5.5 points preoperatively to 8.5 points at the final follow-up and a mean recovery rate of 54.5%.
  
  
  CONCLUSIONS
  Intraoperative ultrasonography and ITN are safe and reliable imaging methods for posterior decompression and instrumented fusion for thoracic myelopathy caused by OPLL.
authors: Department of Spine Surgery, Peking University Fourth Clinical Medical College, Beijing Jishuitan Hospital, Beijing, PR China. orthdanielcw@yahoo.com
authors: Wei
authors: W
authors: Tian
authors: Chong
authors: C
authors: Weng
authors: Bo
authors: B
authors: Liu
authors: Qin
authors: Q
authors: Li
authors: Yu-Qing
authors: YQ
authors: Sun
authors: Qiang
authors: Q
authors: Yuan
authors: Bo
authors: B
authors: Zhang
authors: Yong-Qing
authors: YQ
authors: Wang
authors: Da
authors: D
authors: He
mesh_terms: D000328:Adult; D000368:Aged; D019299:Decompression, Surgical / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D017887:Ossification of Posterior Longitudinal Ligament / Q000000981:diagnostic imaging / Q000601:surgery*; D011184:Postoperative Period; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome; D014463:Ultrasonography