Editorial: Perioperative outcomes and adverse events of minimally invasive surgery during transforaminal lumbar interbody fusion/posterior lumbar interbody fusion.

Goldstein et al. performed a systematic review of the literature and a meta-analysis of the study results comparing acute perioperative outcomes and adverse event rates of minimally invasive surgery (MIS) versus open transforaminal lumbar interbody fusion (TLIF)/posterior lumbar interbody fusion (PLIF) surgery for degenerative lumbar disease.1 The authors also summarized data pertaining to patient-reported outcomes, fusion status, and reoperation rates. From 3301 papers, 26 studies met the inclusion criteria for this analysis. Only 1 prospective randomized controlled trial (RCT) was included, whereas the remaining 25 were either prospective or retrospective comparative studies. The authors have conducted a thorough and exhaustive review of the literature and are to be congratulated for incorporating measures outlined in the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines for the performance and reporting of systematic reviews and meta-analyses. Utilizing the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) protocol, the strength of the included studies was designated as “low” and “very low” quality. By pooling populations among these studies, data from more than 800 patients in each treatment cohort were analyzed. Although no significant difference in operative time was identified, estimated blood loss, time to ambulation, and length of hospital stay all favored MIS techniques. Adverse event rates were similar between the two groups; however, the incidence of medical complications was higher in the open cohort. No differences in the rates of nonunion or reoperation were identified. Both patient populations demonstrated improved outcomes; however, a small, but significantly superior, improvement in ODI scores was observed following MIS procedures. As with any literature review, this study is limited by the strength and quality of the data analyzed. Compared to other reviews, this investigation benefits from the inclusion of only comparative studies and the thorough analysis of methodological quality. Heterogeneity among patients, small sample sizes, lack of consistent reporting, and subjective treatment allocation are among the major limitations that introduce bias in these studies reviewed. Without well-designed RCTs, it is possible that an applesto-oranges situation exists wherein the less difficult cases would be treated with MIS procedures. This could certainly impact patient outcomes and compromise the validity of any analysis. In addition, the definition of MIS techniques is often ambiguous in many of these studies. A potential issue is that authors are writing articles comparing the newer MIS techniques versus the older open procedures, and as such, there may be a bias towards demonstrating more favorable outcomes for the newer MIS procedures. Although not clearly identified in this review, major concerns regarding studies analyzing MIS procedures have been the duration of follow-up and method, or lack of, fusion assessment. Despite substantial limitations in the available literature on this topic, the authors have done an excellent job of summarizing the available data and providing a thoughtful discussion. Their conclusion, that a well-designed,