title: Intraoperative ultrasonography in "cave-in" 360° circumferential decompression for thoracic spinal stenosis.
abstract: BACKGROUND
  The surgical outcomes of decompression for thoracic spinal stenosis (TSS) are unfavorable. The purpose of this study was to determine the efficacy of intraoperative ultrasonography during "cave-in" 360° circumferential decompression surgery in patients with TSS.
  
  
  METHODS
  Thirteen patients with TSS underwent "cave-in" 360° circumferential decompression surgery between May 2010 and November 2010. Intraoperative ultrasonography was used after removal of the posterior wall of thoracic spinal canal to assess the morphologic restoration of the spinal cord and the anterior surface of the spinal canal. In seven patients, ultrasonography was used again after circumferential decompression to compare the cross-sectional area of the spinal cord before and after circumferential decompression.
  
  
  RESULTS
  The average period of follow-up was (12 ± 2) months (range 9 - 15 months). The Japanese Orthopedic Association score was significantly higher at the final follow-up (8.5 ± 2.1, range 3 - 10) than preoperatively (5.2 ± 1.1, range 3 - 7; P < 0.01). The cross-sectional area of the spinal cord was (30.8 ± 6.6) mm2 before and (53.6 ± 19.1) mm2 after circumferential decompression (P < 0.01). For five patients with TSS caused by thoracic disc herniation, the levels of circumferential decompression performed corresponded to those expected preoperatively. In contrast, for eight patients with TSS caused by ossification of the posterior longitudinal ligament, on average 1.6 ± 0.9 fewer levels of circumferential decompression were performed than expected preoperatively.
  
  
  CONCLUSIONS
  "Cave-in" 360° circumferential decompression is an effective therapeutic option for TSS. Intraoperative ultrasonographic evaluation may reduce the levels of circumferential decompression and ensure sufficient decompression, and increase the efficacy of this surgical technique.
authors.affiliation: Department of Orthopaedics, Peking University Third Hospital, Beijing 100191, China.
authors.forename: Yong-Qiang
authors.initials: YQ
authors.lastname: Wang
authors.forename: Xiao-Guang
authors.initials: XG
authors.lastname: Liu
authors.forename: Liang
authors.initials: L
authors.lastname: Jiang
authors.forename: Ling
authors.initials: L
authors.lastname: Jiang
authors.forename: Feng
authors.initials: F
authors.lastname: Wei
authors.forename: Miao
authors.initials: M
authors.lastname: Yu
authors.forename: Zhong-Jun
authors.initials: ZJ
authors.lastname: Liu
mesh_terms: D000328:Adult; D019299:Decompression, Surgical / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013130:Spinal Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D014463:Ultrasonography; D055815:Young Adult