Meta-analysis of instrumented posterior interbody fusion versus instrumented posterolateral fusion in the lumbar spine: A review

Zhi-Jie Zhou, M.D., Ph.D., Feng-Dong Zhao, M.D., Xiang-Qian Fang, M.D., Xing Zhao, M.D., and Shun-Wu Fan, M.D., Ph.D.
Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital, School of Medicine, Medical College of Zhejiang University, and Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, Hangzhou, People's Republic of China

Abbreviations used in this paper: iPLF = instrumented posterolateral fusion; iPLIF = instrumented posterior lumbar interbody fusion; LBP = low-back pain; RCT = randomized controlled trial.

Object
The authors compared the effectiveness of instrumented posterior lumbar interbody fusion (iPLIF) and instrumented posterolateral fusion (iPLF) for the treatment of low-back pain (LBP) due to degenerative lumbar disease.

Methods
Relevant randomized controlled trials (RCTs) and comparative observational studies through December 2009 were identified using a retrieval strategy of sensitive and specific searches. The study design, participant characteristics, interventions, follow-up rate and period, and outcomes were abstracted after the assessment of methodological quality of the trials. Analyses were performed following the method guidelines of the Cochrane Back Review Group.

Results
Nine studies were identified—3 RCTs and 6 comparative observational studies. No significant difference was found between the 2 fusion procedures in the global assessment of clinical outcome (OR 1.51, 95% CI 0.71–3.22, p = 0.29) and complication rate (OR 0.55, 95% CI 0.16–1.86, p = 0.34). Both techniques were effective in reducing pain and improving functional disability, as well as restoring intervertebral disc height. Instrumented PLIF was more effective in achieving solid fusion (OR 2.60, 95% CI 1.35–5.00, p = 0.004), a lower reoperation rate (OR 0.20, 95% CI 0.03–1.29, p = 0.09), and better restoration of segmental angle and lumbar lordotic angle than iPLF. There were no significant differences between the fusion methods regarding blood loss (weighted mean difference –179.63, 95% CI –516.42 to 157.15, p = 0.30), and operating time (weighted mean difference 8.03, 95% CI –45.46 to 61.53, p = 0.77).

Conclusions
The authors' analysis provided moderate-quality evidence that iPLIF has the advantages of higher fusion rate and better restoration of spinal alignment over iPLF. No significant differences were identified between iPLIF and iPLF concerning clinical outcome, complication rate, operating time, and blood loss.