title: Postoperative cervical sagittal imbalance negatively affects outcomes after surgery for cervical spondylotic myelopathy.
abstract: METHODS
  Prospective observational cohort study.
  
  
  OBJECTIVE
  To determine if postoperative cervical sagittal balance is an independent predictor of health-related quality of life outcome after surgery for cervical spondylotic myelopathy.
  
  
  BACKGROUND
  Both ventral and dorsal fusion procedures for CSM are effective at reducing the symptoms of myelopathy. The importance of cervical sagittal balance in predicting overall health-related quality of life outcome after ventral versus dorsal surgery for CSM has not been previously explored.
  
  
  METHODS
  A prospective, nonrandomized cohort of 49 patients undergoing dorsal and ventral fusion surgery for CSM was examined. Preoperative and postoperative C2-C7 sagittal vertical axis was measured on standing lateral cervical spine radiographs. Outcome was assessed with 2 disease-specific measures-the modified Japanese Orthopedic Association scale and the Oswestry Neck Disability Index and 2 generalized outcome measures-the Short-Form 36 physical component summary (SF-36 PCS) and Euro-QOL-5D. Assessments were performed preoperatively, and at 3 months, 6 months, and 1 year postoperatively. Statistical analyses were performed using SAS version 9.3 (SAS Institute).
  
  
  RESULTS
  Most patients experienced improvement in all outcome measures regardless of approach. Both preoperative and postoperative C2-C7 sagittal vertical axis measurements were independent predictors of clinically significant improvement in SF-36 PCS scores (P = 0.03 and P = 0.02). The majority of patients with C2-C7 sagittal vertical axis values greater than 40 mm did not improve from an overall health-related quality of life perspective (SF-36 PCS) despite improvement in myelopathy. The postoperative sagittal balance value was inversely correlated with a clinically significant improvement of SF-36 PCS scores in patients undergoing dorsal surgery but not ventral surgery (P = 0.03 vs. P = 0.93).
  
  
  CONCLUSIONS
  Preoperative and postoperative sagittal balance measurements independently predict clinical outcomes after surgery for CSM.
  
  
  METHODS
  2.
authors.affiliation: *Department of Neurosurgery, Alan and Jacqueline Stuart Spine Research Center, Lahey Hospital and Medical Center, Burlington, MA †Department of Neurosurgery, Tufts University School of Medicine, Boston, MA ‡Harvard School of Public Health, Harvard University, Boston, MA §The Center for Spine Health and Department of Neurosurgery, Cleveland Clinic, Cleveland, OH ¶Department of Neurosurgery, University of Utah, Salt Lake City, UT ∥MetroHealth Spine Center and Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH **Department of Neurosurgery, Massachusetts General Hospital, Boston, MA; and ††Department of Neurosurgery, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, NJ.
authors.forename: Marie
authors.initials: M
authors.lastname: Roguski
authors.forename: Edward C
authors.initials: EC
authors.lastname: Benzel
authors.forename: Jill N
authors.initials: JN
authors.lastname: Curran
authors.forename: Subu N
authors.initials: SN
authors.lastname: Magge
authors.forename: Erica F
authors.initials: EF
authors.lastname: Bisson
authors.forename: Ajit A
authors.initials: AA
authors.lastname: Krishnaney
authors.forename: Michael P
authors.initials: MP
authors.lastname: Steinmetz
authors.forename: William E
authors.initials: WE
authors.lastname: Butler
authors.forename: Robert F
authors.initials: RF
authors.lastname: Heary
authors.forename: Zoher
authors.initials: Z
authors.lastname: Ghogawala
mesh_terms: D000368:Aged; D002574:Cervical Vertebrae / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology; D004856:Postural Balance; D011446:Prospective Studies; D011788:Quality of Life; D012678:Sensation Disorders / Q000209:etiology* / Q000503:physiopathology; D013123:Spinal Fusion / Q000009:adverse effects; D055009:Spondylosis / Q000601:surgery*; D016896:Treatment Outcome