title: Comparison of unilateral versus bilateral pedicle screw fixation with cage fusion in degenerative lumbar diseases: a meta-analysis.
abstract: OBJECTIVE
  To compare the results between unilateral and bilateral pedicle screw (PS) fixation for the patients with degenerative lumbar diseases.
  
  
  METHODS
  A systematic review and meta-analysis of cohort studies were conducted between unilateral PS fixation with cage fusion (unilateral group) and bilateral PS fixation with cage fusion (bilateral group) for the treatment of degenerative lumbar diseases from 1990 to June 2014. An extensive search of studies was performed in PubMed, Mediline, Embase and the Cochrane library. The following outcome measures were extracted: visual analogue scale (VAS), Oswestry disability index (ODI), Short-Form health survey (SF-36), fusion rate, complications, blood loss and operation time. Data analysis was conducted with RevMan 5.0.
  
  
  RESULTS
  Eight RCTs involving 545 patients were included in this meta-analysis. The pooled analysis showed that there was no statistically significant difference in terms of the VAS, ODI and SF-36 scores, fusion rate [OR = 0.49 (0.23, 1.04), P = 0.06], complication rate(implant-related complication: P = 0.35, general complication rate: P = 0.71) and blood loss between two groups. However, there was less operation time in the unilateral group compared with bilateral group. Four patients (1.48 %) in unilateral group and one patient (0.36 %) in bilateral group were found cage migration, the difference did not achieve statistical significance (P = 0.213).
  
  
  CONCLUSIONS
  As compared to bilateral PS fixation with cage fusion, unilateral PS fixation with cage fusion achieves a similar VAS, ODI and SF-36 scores, fusion rate, complications and smaller surgical trauma. However, it is still uncertain whether unilateral pedicle screw fixation with cage fusion is as effective and safe as bilateral pedicle screw fixation with cage fusion.
authors.affiliation: Department of Spine Surgery, The First Affiliated Hospital of Guangxi Medical University, Shuangyong Road No. 6, Nanning, 530021, China.
authors.forename: Shan-Wen
authors.initials: SW
authors.lastname: Xiao
authors.forename: Hua
authors.initials: H
authors.lastname: Jiang
authors.forename: Li-Jing
authors.initials: LJ
authors.lastname: Yang
authors.forename: Zeng-Ming
authors.initials: ZM
authors.lastname: Xiao
mesh_terms: D005260:Female; D005593:Fracture Fixation, Internal / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008161:Lumbosacral Region / Q000601:surgery*; D008297:Male; D010147:Pain Measurement; D065289:Pedicle Screws / Q000009:adverse effects*; D011183:Postoperative Complications; D013123:Spinal Fusion / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome