title: Anterior Cervical Discectomy and Fusion Alters Whole-Spine Sagittal Alignment.
abstract: OBJECTIVE
  Anterior cervical discectomy and fusion (ACDF) has become a common spine procedure, however, there have been no previous studies on whole spine alignment changes after cervical fusion. Our purpose in this study was to determine whole spine sagittal alignment and pelvic alignment changes after ACDF.
  
  
  METHODS
  Forty-eight patients who had undergone ACDF from January 2011 to December 2012 were enrolled in this study. Cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis (SVA), and pelvic parameters were measured preoperatively and at 1, 3, 6, and 12 months postoperatively. Clinical outcomes were assessed using Visual Analog Scale (VAS) scores and Neck Disability Index (NDI) values.
  
  
  RESULTS
  Forty-eight patients were grouped according to operative method (cage only, cage & plate), operative level (upper level: C3/4 & C4/5; lower level: C5/6 & C6/7), and cervical lordosis (high lordosis, low lordosis). All patients experienced significant improvements in VAS scores and NDI values after surgery. Among the radiologic parameters, pelvic tilt increased and sacral slope decreased at 12 months postoperatively. Only the high cervical lordosis group showed significantly-decreased cervical lordosis and a shortened SVA postoperatively. Correlation tests revealed that cervical lordosis was significantly correlated with SVA and that SVA was significantly correlated with pelvic tilt and sacral slope.
  
  
  CONCLUSIONS
  ACDF affects whole spine sagittal alignment, especially in patients with high cervical lordosis. In these patients, alteration of cervical lordosis to a normal angle shortened the SVA and resulted in reciprocal changes in pelvic tilt and sacral slope.
authors.affiliation: Department of Neurosurgery, Gangnam Severance Hospital, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jang Hoon
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Gangnam Severance Hospital, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea. spinepjy@yuhs.ac.
authors.forename: Jeong Yoon
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seong
authors.initials: S
authors.lastname: Yi
authors.affiliation: Department of Neurosurgery, Gangnam Severance Hospital, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kyung Hyun
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Gangnam Severance Hospital, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Sung Uk
authors.initials: SU
authors.lastname: Kuh
authors.affiliation: Department of Neurosurgery, Gangnam Severance Hospital, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Dong Kyu
authors.initials: DK
authors.lastname: Chin
authors.affiliation: Department of Neurosurgery, Gangnam Severance Hospital, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Keun Su
authors.initials: KS
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Gangnam Severance Hospital, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yong Eun
authors.initials: YE
authors.lastname: Cho
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D003430:Cross-Sectional Studies; D017586:Diskectomy; D005260:Female; D006801:Humans; D008141:Lordosis / Q000209:etiology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000601:surgery; D011859:Radiography; D012189:Retrospective Studies; D013122:Spinal Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D013131:Spine; D016896:Treatment Outcome; D055815:Young Adult
keywords: ACDF; pelvic parameters; whole spine sagittal alignment