title: Comparison of one versus two cages in lumbar interbody fusion for degenerative lumbar spinal disease: a meta-analysis.
abstract: OBJECTIVE
  To systematically compare the fusion rate and safety of lumbar interbody fusion using one cage versus two cages for the treatment of degenerative lumbar spinal diseases.
  
  
  METHODS
  All randomized controlled trials (RCTs) and comparative observational studies written in English comparing the outcome of lumbar interbody fusion using one or two cages in patients with degenerative lumbar spinal diseases were identified by a comprehensive search of PubMed Central, MEDLINE, EMBASE, BIOSIS and the Cochrane Central Registry of Controlled Trials. An exhaustive electronic search up to July 2013. The quality of the methodology was assessed and relevant data retrieved independently by two reviewers, after which the resultant data were subjected to meta-analysis. All meta-analyses were performed using Review Manager 5.0, which is recommended and provided by the Cochrane Collaboration.
  
  
  RESULTS
  Our systematic search yielded 745 studies from the selected databases. After duplicate studies had been identified and the titles and abstracts screened, 736 studies were excluded because they were irrelevant to our topic. The full texts of the remaining nine potentially relevant references were comprehensively evaluated and four excluded for the following reasons: two studies involved co-interventions and the other two lacked control groups. Two relevant RCTs and three comparative observational studies involving 384 patients and 501 spinal segments with at least one year follow-up were identified. Analysis of the pooled data demonstrated no significant difference in fusion rate between the one-cage and two-cage groups. However, intraoperative blood loss and operating time were less and the complications rate lower in the one-cage group.
  
  
  CONCLUSIONS
  In patients with degenerative lumbar spinal diseases, lumbar interbody fusion using one cage has an equal fusion rate and is safer compared with using two cages. However, because this meta-analysis had some limitations, more high quality RCTs are needed to strengthen the evidence.
authors.affiliation: Department of Spine Surgery, Sichuan Orthopaedic Hospital; Department of Orthopaedics, West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
authors.forename: Jing
authors.initials: J
authors.lastname: Tang
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
mesh_terms: D016063:Blood Loss, Surgical; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000601:surgery; D007432:Intraoperative Period; D008159:Lumbar Vertebrae / Q000601:surgery*; D019736:Prostheses and Implants; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D013122:Spinal Diseases / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods
keywords: Cage; Fusion rate; Lumbar interbody fusion; Meta-analysis