title: Two-level corpectomy versus three-level discectomy for cervical spondylotic myelopathy: a comparison of perioperative, radiographic, and clinical outcomes.
abstract: OBJECTIVE
  In the treatment of cervical spondylotic myelopathy (CSM), anterior cervical corpectomy and fusion (ACCF) and anterior cervical discectomy and fusion (ACDF) are effective decompressive techniques. It remains to be determined whether ACCF and ACDF offer equivalent outcomes for multilevel CSM. In this study, the authors compared perioperative, radiographic, and clinical outcomes between 2-level ACCF and 3-level ACDF.
  
  
  METHODS
  Between 2006 and 2012, all patients at the authors' hospital who underwent 2-level ACCF or 3-level ACDF performed by 1 of 2 surgeons were identified. Primary outcomes of interest were sagittal Cobb angle, adjacent-segment disease (ASD) requiring surgery, neck pain measured by visual analog scale (VAS), and Nurick score. Secondary outcomes of interest included estimated blood loss (EBL), length of stay, perioperative complications, and radiographic pseudarthrosis rate. Chi-square tests and 2-tailed Student t-tests were used to compare the 2 groups. A subgroup analysis of patients without posterior spinal fusion (PSF) was also performed.
  
  
  RESULTS
  Twenty patients underwent 2-level ACCF, and 35 patients underwent 3-level ACDF during a 6-year period. Preoperative Nurick scores were higher in the ACCF group (2.1 vs 1.1, p = 0.014), and more patients underwent PSF in the 2-level ACCF group compared with patients in the 3-level ACDF group (60.0% vs 17.1%, p = 0.001). Otherwise there were no significant differences in demographics, comorbidities, and baseline clinical parameters between the 2 groups. Two-level ACCF was associated with significantly higher EBL compared with 3-level ACDF for the anterior stage of surgery (382.2 ml vs 117.9 ml, p < 0.001). Two-level ACCF was also associated with a longer hospital stay compared with 3-level ACDF (7.2 days vs 4.9 days, p = 0.048), but a subgroup comparison of patients without PSF showed no significant difference in length of stay (3.1 days vs 4.4 days for 2-level ACCF vs 3-level ACDF, respectively; p = 0.267). Similarly, there was a trend toward more complications in the 2-level ACCF group (20.0%) than the 3-level ACDF group (5.7%; p = 0.102), but a subgroup analysis that excluded those who had second-stage PSF no longer showed the same trend (2-level ACCF, 0.0% vs 3-level ACDF, 3.4%; p = 0.594). There were no significant differences between the ACCF group and the ACDF group in terms of postoperative sagittal Cobb angle (7.2° vs 12.1°, p = 0.173), operative ASD (6.3% vs 3.6%, p = 0.682), and radiographic pseudarthrosis rate (6.3% vs 7.1%, p = 0.909). Both groups had similar improvement in mean VAS neck pain scores (3.4 vs 3.2 for ACCF vs ACDF, respectively; p = 0.860) and Nurick scores (0.8 vs 0.7, p = 0.925).
  
  
  CONCLUSIONS
  Two-level ACCF was associated with greater EBL and longer hospital stays when patients underwent a second-stage PSF. However, the length of stay was similar when patients underwent anterior-only decompression with either 2-level ACCF or 3-level ACDF. Furthermore, perioperative complication rates were similar in the 2 groups when patients underwent anterior decompression without PSF. Both groups obtained similar postoperative cervical lordosis, operative ASD rates, radiographic pseudarthrosis rates, neurological improvement, and pain relief.
authors.affiliation: Department of Neurological Surgery, University of California, San Francisco, California.
authors.forename: Darryl
authors.initials: D
authors.lastname: Lau
authors.affiliation: Department of Neurological Surgery, University of California, San Francisco, California.
authors.forename: Dean
authors.initials: D
authors.lastname: Chou
authors.affiliation: Department of Neurological Surgery, University of California, San Francisco, California.
authors.forename: Praveen V
authors.initials: PV
authors.lastname: Mummaneni
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D019299:Decompression, Surgical / Q000379:methods*; D017586:Diskectomy; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000601:surgery*; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011859:Radiography; D012189:Retrospective Studies; D013123:Spinal Fusion; D055009:Spondylosis / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; C491352:Tcof1 protein, mouse
keywords: ACCF = anterior cervical corpectomy and fusion; ACDF = anterior cervical discectomy and fusion; ASD = adjacent-segment disease; CSM = cervical spondylotic myelopathy; EBL = estimated blood loss; PSF = posterior spinal fusion; VAS = visual analog scale; adjacent-segment disease; cervical spondylotic myelopathy; corpectomy; discectomy; fusion; pseudarthrosis; sagittal curvature