title: Can laminoplasty maintain the cervical alignment even when the C2 lamina is contained?
abstract: METHODS
  Retrospective case-controlled study of cervical laminoplasty.
  
  
  OBJECTIVE
  To evaluate the alignment and clinical result by laminoplasty when the C2 lamina is contained or retained.
  
  
  BACKGROUND
  Resection of the C2 lamina was reported to progress to kyphosis after laminectomy. Laminoplasty was reported to inhibit kyphosis. But no study has ever shown if the alignment is retained when laminoplasty also included the C2 lamina.
  
  
  METHODS
  Seventy-two patients with cervical spondylotic myelopathy undergoing laminoplasty were analyzed. Follow-up averaged 4.0 years. The outcome was assessed by the Cobb angle between C2 and C7, and the motor function scores of the upper and lower extremities for cervical myelopathy were made by the Japanese Orthopedic Association. Patients were stratified into three groups depending on the handling of the C2 lamina: fully split (S group; n = 17), C2 dome-like laminotomy (D group; n = 19), and intact (I group; n = 36). Change of the C2-C7 angle was compared by the analysis of variance and post hoc test. The association between the alignment and the motor scores was analyzed.
  
  
  RESULTS
  Upper/lower score increased from 2.4/2.0 to 3.4/2.9, respectively. The C2-C7 angle decreased in S group: -8.3 degrees , D group: -5.2 degrees , and I group: -1.5 degrees . The cervical alignment deteriorated significantly in S group compared with the I group (P < 0.01). The C2-C7 angle change or postoperative C2-C7 angle had no significant correlation with the postoperative upper and lower m-JOA scores or score change.
  
  
  CONCLUSIONS
  Subaxial laminoplasty maintained the alignment. But if laminoplasty included the C2 lamina, the alignment worsened.
authors.affiliation: Department of Orthopaedic Surgery, the University of Tokyo, Tokyo, Japan. Takeshita-ort@h.u-tokyo.ac.jp
authors.forename: Katsushi
authors.initials: K
authors.lastname: Takeshita
authors.forename: Atsushi
authors.initials: A
authors.lastname: Seichi
authors.forename: Toru
authors.initials: T
authors.lastname: Akune
authors.forename: Naohiro
authors.initials: N
authors.lastname: Kawamura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: Kozo
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002574:Cervical Vertebrae / Q000601:surgery*; D004185:Disability Evaluation; D006801:Humans; D007738:Kyphosis / Q000517:prevention & control*; D007796:Laminectomy / Q000379:methods*; D008875:Middle Aged; D020127:Recovery of Function; D012189:Retrospective Studies; D013117:Spinal Cord Compression / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D013130:Spinal Stenosis / Q000150:complications / Q000503:physiopathology / Q000601:surgery*