Prevalence and risk factors for cage subsidence after lumbar interbody fusion A protocol for systematic review and meta-analysis

Introduction: Lumbar interbody fusion (LIF) is an effective treatment for lumbar degenerative diseases. Cage subsidence (CS) contitutes one of the most common postoperative complications. Many risk factors for CS after LIF have been reported in some studies. However, controversies still exist. The objective of this study will be to summarize data on the prevalence and risk factors of CS after LIF. Methods and analysis: Our study present a protocol that conducted a systematic review and meta-analysis of prevalence and risk factors for CS after LIF. Two reviewers retrieved the relevant articles using the 5 databases (PubMed, Scopus, EMBASE, Cochrane Library, and Web of Science) from inception to May 31st, 2021. Primary outcome will be the prevalence of CS after LIF. Second outcomes include the risk factors associated with postoperative CS and clinical outcomes associated with postoperative CS. Three reviewers will screen citation titles and abstracts and evaluated full-text of each potentially relevant citation, and then extracted the data using a data extraction form. Any discrepancies in decisions between reviewers will be resolved through discussion. We assessed the methodological quality and risk of bias of the included studies based on the Newcastle-Ottawa Quality Assessment Scale (NOS). The aim of the extra analysis is to explore the explanations of the heterogeneity (age, gender, race, year of publication, type of study and surgical procedure). Publication bias will be assessed by Begg test, Egger test and funnel plots.