title: The relationship between changes of cervical sagittal alignment after anterior cervical discectomy and fusion and spino-pelvic sagittal alignment under roussouly classification: a four-year follow-up study.
abstract: Anterior cervical discectomy and fusion (ACDF) is widely used in the treatment of cervical degenerative disease; however, the variation of cervical sagittal alignment changes after ACDF has been rarely explored. The purpose of this study is to determine the relationship between changes of cervical sagittal alignment after ACDF and spino-pelvic sagittal alignment under Roussouly classification.
  
  
  
  A cohort of 133 Chinese cervical spondylotic patients who received ACDF from 2011 to 2012 was recruited. All patients were categorized with Roussouly Classification. Lateral X-ray images of global spine were obtained, and preoperative and postoperative parameters were measured and analyzed, including C2-C7 angles (C2-C7), C0-C7 angles (C0-C7), external auditory meatus (EAM) tilt, sacral slope (SS), thoracic kyphosis (TK), lumbar lordosis (LL), spinal sacral angles (SSA), Superior adjacent inter-vertebral angle (SAIV), inferior adjacent inter-vertebral angle (IAIV) and et al. The Wilcoxon signed-rank test was used for intragroup comparisons preoperatively and at postoperative 48 months.
  
  
  
  Among the parameters, C2-C7 and C0-C7 showed significant increase, while EAM TK, and IAIV decreased significantly. In type I, EAM and TK decreased significantly, however SS showed a significant increase; in type II, TK showed a significant decrease, but SSA showed a significant increase; in type III, a significant increase of C0-C7 was observed with a significant decrease in EAM, nevertheless, LL, SS and SSA showed significant decreases; and in type IV, C2-C7 showed a significant increase and EAM decreased significantly. The percentage of lordotic alignment in cervical spine increased, which was presenting in type I, III and IV. Nevertheless, the amount of patients with straight cervical alignment increased in type II.
  
  
  
  The backward movement of head occurs is the compensatory mechanism in cervical sagittal alignment modifications after ACDF. The compensatory alteration of spino-pelvic sagittal alignment varied in different Roussouly type.
authors.affiliation: Department of Orthopedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
authors.forename: Dong-Ning
authors.initials: DN
authors.lastname: Huang
authors.affiliation: Department of Orthopedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Yu
authors.affiliation: Department of Orthopedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
authors.forename: Nan-Fang
authors.initials: NF
authors.lastname: Xu
authors.affiliation: Department of Orthopedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
authors.forename: Mai
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Orthopedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
authors.forename: Shao-Bo
authors.initials: SB
authors.lastname: Wang
authors.affiliation: Department of Orthopedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Orthopedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Department of Orthopedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wei
authors.affiliation: Department of Orthopedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China. puth_lxg@163.com.
authors.forename: Xiao-Guang
authors.initials: XG
authors.lastname: Liu
authors.affiliation: Department of Orthopedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
authors.forename: Zhong-Jun
authors.initials: ZJ
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery; D015331:Cohort Studies; D017586:Diskectomy / Q000639:trends*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010384:Pelvic Bones / Q000000981:diagnostic imaging* / Q000601:surgery; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000639:trends*; D055009:Spondylosis / Q000145:classification* / Q000000981:diagnostic imaging* / Q000601:surgery; D013997:Time Factors; D055815:Young Adult
keywords: Anterior cervical discectomy and fusion (ACDF); Cervical sagittal alignment; Roussouly classification; Spinopelvic sagittal alignment