A systematic review of clinical outcomes in surgical treatment of adult isthmic spondylolisthesis

Abstract Background Context A variety of surgical methods are available for the treatment of adult isthmic spondylolisthesis, but there is no consensus regarding their relative effects on clinical outcomes. Purpose To compare the effects of different surgical techniques on clinical outcomes in adult isthmic spondylolisthesis. Design A systematic review was carried out. Patient Sample A total of 1,538 patients from six randomized clinical trials (RCTs) and nine observational studies comparing different surgical treatments in adult isthmic spondylolisthesis. Outcome Measures Primary outcome measures of interest included differences in pre- versus postsurgical assessments of pain, functional disability, and overall health as assessed by validated pain rating scales and questionnaires. Secondary outcome measures of interest included intraoperative blood loss, length of hospital stay, surgery duration, reoperation rates, and complication rates. Methods A search of the literature was performed in September 2017 for relevant comparative studies published in the prior 10-year period in the following databases: PubMed, Embase, Web of Science, and ClinicalTrials.gov . Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed and studies were included or excluded based on strict predetermined criteria. Quality appraisal was conducted using the Newcastle-Ottawa scale (NOS) for observational studies and the Cochrane Collaboration risk of bias assessment tool for RCTs. The authors received no funding support to conduct this review. Results A total of 15 studies (six RCTs and nine observational studies) were included for full-text review, a majority of which only included cases of low-grade isthmic spondylolisthesis. One study examined the effects of adding pedicle screw fixation (PS) to posterolateral fusion (PLF) and two studies examined the effects of adding reduction to interbody fusion (IF)+PS on clinical outcomes. Five studies compared PLF, four with PS and one without PS, with IF+PS. Additionally, three studies compared circumferential fusion (IF+PS+PLF) with IF+PS and one study compared circumferential fusion with PLF+PS. Three studies compared clinical outcomes among different IF+PS techniques (anterior lumbar IF [ALIF]+PS vs. posterior lumbar IF [PLIF]+PS vs. transforaminal lumbar IF [TLIF]+PS) without PLF. As per the Cochrane Collaboration risk of bias assessment tool, four RCTs had an overall low risk of bias, one RCT had an unclear risk of bias, and one RCT had a high risk of bias. As per the NOS, three observational studies were of overall good quality, four observational studies were of fair quality, and two observational studies were of poor quality. Conclusions Available studies provide strong evidence that the addition of reduction to fusion does not result in better clinical outcomes of pain and function in low-grade isthmic spondylolisthesis. Evidence also suggests that there is no significant difference between interbody fusion (IF+PS) and posterior fusion (PLF±PS) in outcomes of pain, function, and complication rates at follow-up points up to approximately 3 years in cases of low-grade slips. However, studies with longer follow-up points suggest that interbody fusion (IF+PS) may perform better in these same measures at later follow-up points. Available evidence also suggests no difference between circumferential fusion (IF+PS+PLF) and interbody fusion (IF+PS) in outcomes of pain and function in low-grade slips, but circumferential fusion has been associated with greater intraoperative blood loss, longer surgery duration, and longer hospital stays. In terms of clinical outcomes, insufficient evidence is available to assess the utility of adding PS to PLF, the relative efficacy of different interbody fusion (IF+PS) techniques (ALIF+PS vs. TLIF+PS vs. PLIF+PS), and the relative efficacy of circumferential fusion and posterior fusion (PLF+PS).