title: Analysis of correlative risk factors for C5 palsy after anterior cervical decompression and fusion.
abstract: BACKGROUND
  It has been reported that C5 palsy is a potential complication of both anterior and posterior cervical spine surgery, although several mechanisms of C5 palsy following posterior cervical surgery have been proposed, few reports about correlative risk factors have been elaborated on C5 palsy after anterior cervical decompression and fusion (ACDF).
  
  
  OBJECTIVE
  The purpose of this study was to investigate the correlative risk factors of C5 palsy after anterior cervical decompression and fusion.
  
  
  METHODS
  This is a retrospective study. A total of 161 patients (108 males and 53 females) who underwent ACDF between 2007 and 2012 were included in this study. C5 palsy is characterized by deltoid and/or biceps brachii weakness. The patients were divided into two groups: one that had experienced C5 palsy (group A) and the other one had not (group B). In both groups, the age, gender, duration of disease, diagnosis, No. of surgical levels, cervical curvature correction, occupying rate of spinal canal at C4/5, diameter of the C4/5 foramen, intervertebral height variation, decompression width and preoperative high-signal intensity zone (HIZ) of spinal cord in T2-weighted MRI at C4/5 were measured and evaluated. The risk factors of C5 palsy were detected with logistic regression analysis.
  
  
  RESULTS
  There were no significant differences in age, gender, duration of disease, diagnosis, No. of surgical levels, rate of spinal canal at C4/5 and HIZ of spinal cord in T2-weighted MRI at C4/5. Cervical curvature correction, diameter of the C4/5 foramen, intervertebral height variation and decompression width had significant differences between the two groups (P<0.05). Logistic regression analysis revealed that cervical curvature, diameter of the C4/5 foramen, intervertebral height and decompression width were the pivotal risk factors for the incidence of C5 palsy.
  
  
  CONCLUSIONS
  For patients with ACDF, greater cervical curvature correction, narrow diameter of the C4/5 foramen, improper intervertebral height variation and larger decompression width were the correlative risk factors for C5 palsy after ACDF.
authors.affiliation: Department of Spinal Surgery, Hebei Provincial Key Laboratory of Orthopaedic Biomechanics, The Third Hospital of Hebei Medical University Shijiazhuang 050051, China.
authors.forename: Haiying
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Spinal Surgery, Hebei Provincial Key Laboratory of Orthopaedic Biomechanics, The Third Hospital of Hebei Medical University Shijiazhuang 050051, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Hebei Medical University Shijiazhuang 050000, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Lv
authors.affiliation: Department of Spinal Surgery, Hebei Provincial Key Laboratory of Orthopaedic Biomechanics, The Third Hospital of Hebei Medical University Shijiazhuang 050051, China.
authors.forename: Wenyuan
authors.initials: W
authors.lastname: Ding
authors.affiliation: Department of Spinal Surgery, Hebei Provincial Key Laboratory of Orthopaedic Biomechanics, The Third Hospital of Hebei Medical University Shijiazhuang 050051, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Spinal Surgery, Hebei Provincial Key Laboratory of Orthopaedic Biomechanics, The Third Hospital of Hebei Medical University Shijiazhuang 050051, China.
authors.forename: Dalong
authors.initials: D
authors.lastname: Yang
authors.affiliation: Department of Spinal Surgery, Hebei Provincial Key Laboratory of Orthopaedic Biomechanics, The Third Hospital of Hebei Medical University Shijiazhuang 050051, China.
authors.forename: Zhilong
authors.initials: Z
authors.lastname: Bai
keywords: C5 palsy; Cervical spine; anterior cervical surgery; decompression; risk factor