title: Comparison of unilateral versus bilateral pedicle screw fixation in degenerative lumbar diseases: a meta-analysis.
abstract: OBJECTIVE
  Traditionally, lumbar spinal surgery is performed with bilateral pedicle screw fixation to provide stability as the fusion heals. However, many studies have reported that unilateral pedicle screw fixation is as effective as bilateral constructs. To compare the clinical outcomes, complications, and surgical trauma between the two techniques for treatment of degenerative lumbar diseases, we conducted a meta-analysis.
  
  
  METHODS
  We searched MEDLINE, EMBASE, PubMed, Google Scholar, and Cochrane databases for relevant controlled studies up to August 2013 that compared unilateral with bilateral fixation for the treatment of degenerative lumbar diseases. We independently performed title/abstract screening and full-text screening. A random effects model was used for heterogeneous data; otherwise, a fixed effect model was used, pooling data using mean difference (MD) for continuous outcomes and odds ratio (OR) for dichotomous outcomes.
  
  
  RESULTS
  A total of 12 articles (865 participants) were eligible. Overall, there were significant differences between the two groups for blood loss (MD = -171.73, 95 % CI = -281.70 to -61.76; p = 0.002), operation time (MD = -66.02, 95 % CI = -115.52 to -16.51; p = 0.009), and fusion rate (OR = 0.50, 95 % CI = 0.26-0.96; p = 0.004). However, there were no significant differences in hospital stay (MD = -4.44, 95 % CI = -13.37 to 4.50), ODI (MD = -0.09, 95 % CI = -0.59 to 0.42; p = 0.74), JOA (MD = 0.18, 95 % CI = -0.77 to 1.14; p = 0.71), VAS (MD = -0.04, 95 % CI = -0.16 to 0.08; p = 0.49), SF-36 (PF: MD = -1.11, 95 % CI = -4.38 to 2.17, p = 0.51; GH: MD = 1.22, 95 % CI = -2.17 to 4.60, p = 0.48; MH: MD = -0.22, 95 % CI = -3.83 to 3.38, p = 0.90) and complications (OR = 1.15, 95 % CI = 0.72-1.85; p = 0.56).
  
  
  CONCLUSIONS
  This meta-analysis shows that there was significantly less blood loss in unilateral group and less operating time; however, the fusion rate was significantly higher in the bilateral group. The outcomes of hospital stay, ODI, JOA, VAS, SF-36 score, and complications are similar in the two groups.
authors.affiliation: Department of Spinal Surgery, East Hospital, Tongji University School of Medicine, 150# Jimo RD, Pudong New Area, Shanghai, 200120, China.
authors.forename: Ying-Chao
authors.initials: YC
authors.lastname: Han
authors.forename: Zhu-Qing
authors.initials: ZQ
authors.lastname: Liu
authors.forename: Shan-Jin
authors.initials: SJ
authors.lastname: Wang
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Tan
mesh_terms: D016208:Databases, Factual; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000601:surgery*; D007902:Length of Stay; D008159:Lumbar Vertebrae / Q000601:surgery*; D065289:Pedicle Screws; D011183:Postoperative Complications; D012720:Severity of Illness Index; D016896:Treatment Outcome