title: Unilateral versus bilateral pedicle screw fixation in short-segment lumbar spinal fusion: a meta-analysis of randomised controlled trials.
abstract: OBJECTIVE
  We performed this meta-analysis of randomised controlled trials to compare the efficacy and safety of unilateral with bilateral fixation in short-segment lumbar spinal fusion.
  
  
  METHODS
  Predefined terms were used to search electronic databases to identify relevant research. Randomised controlled trials (RCTs) published in English and Chinese during 1990-2015 investigating efficacy and safety of unilateral and bilateral fixation in short-segment lumbar spinal fusion were included. Data of fusion rate, complications, visual analogue scale (VAS), Oswestry Disability Index (ODI), estimated blood loss (EBL) and length of hospital stay were extracted and analysed. Two reviewers independently searched information sources, selected eligible research, analysed data and evaluated risk of bias.
  
  
  RESULTS
  Eleven RCTs comprising 756 participants were analysed. There was no significant difference in fusion rate, device-related complication, ODI, VAS and length of hospital stay between bilateral and unilateral groups. The unilateral group had the obvious advantage of reduced blood loss [mean difference (MD) -143.57, 95 % confidence interval (Cl) -206.61 to -80.54, P < 0.0001) and operation time (MD -52.72, 95 % Cl -73.58 to -31.87, P < 0.00001).
  
  
  CONCLUSIONS
  Unilateral pedicle screw fixation is equally as effective as bilateral pedicle screw fixation in short-segment lumbar spinal fusion and may reduce operation time and blood loss.
authors.affiliation: Department of Orthopaedic Surgery, The Second Affiliated Hospital, Medical College of Zhejiang University, NO.88 Jiefang Road, Hangzhou, 310009, People's Republic of China.
authors.forename: Zengfeng
authors.initials: Z
authors.lastname: Xin
authors.affiliation: Department of Orthopaedic Surgery, The Second Affiliated Hospital, Medical College of Zhejiang University, NO.88 Jiefang Road, Hangzhou, 310009, People's Republic of China. liweixu@163.com.
authors.forename: Weixu
authors.initials: W
authors.lastname: Li
mesh_terms: D000368:Aged; D016208:Databases, Factual; D005593:Fracture Fixation, Internal / Q000379:methods*; D006801:Humans; D007902:Length of Stay; D008159:Lumbar Vertebrae / Q000601:surgery*; D008875:Middle Aged; D010147:Pain Measurement; D065289:Pedicle Screws; D011183:Postoperative Complications; D013123:Spinal Fusion / Q000295:instrumentation*; D064232:Visual Analog Scale
keywords: Bilateral; Lumbar fusion; Pedicle screw; Unilateral