Effect of interbody fusion compared with posterolateral fusion on lumbar degenerative spondylolisthesis: a systematic review and meta-analysis

Background context: Lumbar degenerative spondylolisthesis is a relatively common pathology, and surgical treatment is an option in selected cases. The common use of anterior column support by interbody fusion (IBF) has not been adequately studied.

Purpose: The primary objective of this systematic review and meta-analysis was to compare the functional and surgical outcomes after posterolateral fusion (PLF) and IBF for the treatment of degenerative spondylolisthesis.

Study design: A systematic review and meta-analysis was conducted to identify studies analyzing the effects of IBF compared to those of instrumented PLF on degenerative spondylolisthesis.

Patient sample: A total of 1,063 patients were included in the analysis. Of them, 470 patients were treated with PLF and 593 with IBF.

Outcome measures: The outcomes analyzed were the visual analog scale and numerical rating scale scores for back pain, Oswestry Disability Index (ODI), 36-Item Short Form Health Survey (SF-36) score, 12-Item Short Form Health Survey (physical and mental components) score, blood loss amount, surgical time, hospital stay duration, fusion rate, lumbar lordosis, sacral slope, and postoperative complications.

Methods: A search was conducted using the MEDLINE, Cochrane, and Google Scholar databases for studies published between January 1985 and February 2021. Both retrospective and prospective studies that compared between IBF and PLF were included.

Results: A total of 2,819 articles were screened, and 38 full-text articles were selected for a detailed investigation, of which 12 articles were found to match all the inclusion criteria and were included in the meta-analysis. There was an improvement in the sacral slope (mean difference [MD] = 3 [95% confidence interval {CI} = 0.83-5.17]) and fusion rate (odds ratio [OR] = 0.47 [95% CI = 0.26-0.86]) in the IBF group. The incidence of neural injury was higher in the IBF group (OR = 0.28 [95% CI = 0.13-0.60]) than in the PLF group. There were no differences in the back pain scores, ODI, SF-36 score, blood loss amount, surgical time, hospital stay duration, lumbar lordosis, infection, and durotomy between the groups.

Conclusions: IBF for the treatment of lumbar degenerative spondylolisthesis showed better results in terms of the fusion rate and sacral slope, but which did not translate into better clinical outcomes. Further randomized and prospective studies are necessary to elucidate the optimal therapeutic options.