title: Is posterior spinal cord shifting by extensive posterior decompression clinically significant for multisegmental cervical spondylotic myelopathy?
abstract: METHODS
  Posterior cervical spinal cord shifting after selective single laminectomy associated with partial laminotomies was compared with that after bilateral open-door laminoplasty between the C3 and C7 levels in relation to the clinical results of each procedure.
  
  
  OBJECTIVE
  To investigate the clinical significance of posterior spinal cord shifting after extensive cervical laminoplasty.
  
  
  BACKGROUND
  Current techniques used for cervical laminoplasty for multisegmental cervical spondylotic myelopathy (CSM) are consecutively performed between the C3 and C6 or C7 levels with expectation that the spinal cord will shift backward to keep it clear of anterior compression. However, the clinical significance of the posterior spinal cord shifting remains controversial, and there has been no report verifying it by comparing limited posterior decompression procedures with conventional extensive ones.
  
  
  METHODS
  Twenty-six patients with consecutive 2- to 3-level CSM who underwent selective laminoplasty (Group A) were enrolled in the study, and among 56 CSM patients who underwent bilateral open-door laminoplasty between the C3 and C7 levels, 25 who had consecutive 2- or 3- level stenosis identified by preoperative magnetic resonance imaging were used as controls (Group B). The recovery rate was calculated using preoperative and postoperative Japanese Orthopedic Association (JOA) scores for each patient, and for each patient's magnetic resonance imaging, the postoperative cervical curvature index was obtained according to Ishihara's method and the magnitude of postoperative backward shifting of the spinal cord was measured.
  
  
  RESULTS
  There was no significant difference between the subjects in Groups A and B with respect to the spinal curvature index, preoperative JOA scores, and recovery rate, but the magnitude of the postoperative posterior shifting of the spinal cord was greater for those in Group B than for those in Group A. There was no correlation between the recovery rate and posterior shifting of the spinal cord for each group, and no correlation was also found between the curvature index and posterior shifting of the spinal cord.
  
  
  CONCLUSIONS
  The outcome of posterior decompression surgery for multisegmental CSM is not correlated with the magnitude of postoperative backward shifting of the spinal cord. Extensive and consecutive decompression performed in conventional cervical laminoplasties is therefore not always necessary for multisegmental CSM.
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. hilokai@zeus.eonet.ne.jp
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Hatta
authors.forename: Tateru
authors.initials: T
authors.lastname: Shiraishi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hase
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Yato
authors.forename: Seiji
authors.initials: S
authors.lastname: Ueda
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Mikami
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Harada
authors.forename: Takumi
authors.initials: T
authors.lastname: Ikeda
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000601:surgery; D019299:Decompression, Surgical / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000009:adverse effects*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013116:Spinal Cord / Q000473:pathology*; D013119:Spinal Cord Injuries / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D013130:Spinal Stenosis / Q000209:etiology / Q000473:pathology*; D016896:Treatment Outcome