title: Reoperation After Cervical Disc Arthroplasty Versus Anterior Cervical Discectomy and Fusion: A Meta-analysis.
abstract: BACKGROUND
  Anterior cervical discectomy and fusion is a standard surgical treatment for cervical radiculopathy and myelopathy, but reoperations sometimes are performed to treat complications of fusion such as pseudarthrosis and adjacent-segment degeneration. A cervical disc arthroplasty is designed to preserve motion and avoid the shortcomings of fusion. Available evidence suggests that a cervical disc arthroplasty can provide pain relief and functional improvements similar or superior to an anterior cervical discectomy and fusion. However, there is controversy regarding whether a cervical disc arthroplasty can reduce the frequency of reoperations.
  
  
  OBJECTIVE
  We performed a meta-analysis of randomized controlled trials (RCTs) to compare cervical disc arthroplasty with anterior cervical discectomy and fusion regarding (1) the overall frequency of reoperation at the index and adjacent levels; (2) the frequency of reoperation at the index level; and (3) the frequency of reoperation at the adjacent levels.
  
  
  METHODS
  PubMed, EMBASE, and the Cochrane Register of Controlled Trials databases were searched to identify RCTs comparing cervical disc arthroplasty with anterior cervical discectomy and fusion and reporting the frequency of reoperation. We also manually searched the reference lists of articles and reviews for possible relevant studies. Twelve RCTs with a total of 3234 randomized patients were included. Eight types of disc prostheses were used in the included studies. In the anterior cervical discectomy and fusion group, autograft was used in one study and allograft in 11 studies. Nine of 12 studies were industry sponsored. Pooled risk ratio (RR) and associated 95% CI were calculated for the frequency of reoperation using random-effects or fixed-effects models depending on the heterogeneity of the included studies. A funnel plot suggested the possible presence of publication bias in the available pool of studies; that is, the shape of the plot suggests that smaller negative or no-difference studies may have been performed but have not been published, and so were not identified and included in this meta-analysis.
  
  
  RESULTS
  The overall frequency of reoperation at the index and adjacent levels was lower in the cervical disc arthroplasty group (6%; 108/1762) than in the anterior cervical discectomy and fusion group (12%; 171/1472) (RR, 0.54; 95% CI, 0.36-0.80; p = 0.002). Subgroup analyses were performed according to secondary surgical level. Compared with anterior cervical discectomy and fusion, cervical disc arthroplasty was associated with fewer reoperations at the index level (RR, 0.50; 95% CI, 0.37-0.68; p < 0.001) and adjacent levels (RR, 0.52; 95% CI, 0.37-0.74; p < 0.001).
  
  
  CONCLUSIONS
  Cervical disc arthroplasty is associated with fewer reoperations than anterior cervical discectomy and fusion, indicating that it is a safe and effective alternative to fusion for cervical radiculopathy and myelopathy. However, because of some limitations, these findings should be interpreted with caution. Additional studies are needed.
  
  
  METHODS
  Level I, therapeutic study.
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, 510515, China. zhongzm@smu.edu.com.
authors.forename: Zhao-Ming
authors.initials: ZM
authors.lastname: Zhong
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, 510515, China.
authors.forename: Shi-Yuan
authors.initials: SY
authors.lastname: Zhu
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, 510515, China.
authors.forename: Jing-Shen
authors.initials: JS
authors.lastname: Zhuang
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, 510515, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, 510515, China.
authors.forename: Jian-Ting
authors.initials: JT
authors.lastname: Chen
mesh_terms: D001178:Arthroplasty / Q000009:adverse effects*; D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000503:physiopathology / Q000601:surgery*; D016009:Chi-Square Distribution; D017586:Diskectomy / Q000009:adverse effects* / Q000379:methods; D006801:Humans; D007403:Intervertebral Disc / Q000503:physiopathology / Q000601:surgery*; D016017:Odds Ratio; D011183:Postoperative Complications / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D011843:Radiculopathy / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D012086:Reoperation; D018570:Risk Assessment; D012307:Risk Factors; D013118:Spinal Cord Diseases / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects*; D013997:Time Factors; D016896:Treatment Outcome
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