Comparison of BioLIFT versus LIFT for the treatment of trans-sphincteric anal fistula: a protocol for systematic review and meta-analysis

INTRODUCTION: Identifying the optimal treatment for anal fistula has been challenging. Since first reported in 2007, the ligation of the intersphincteric fistula tract (LIFT) procedure has reported healing rates between 40% and 95% and is being increasingly adopted. The BioLIFT is an augmentation of the LIFT with an intersphincteric bioprosthetic mesh and has reported healing rates between 69% and 94%. Despite increased costs and potential complications associated with mesh, the evidence comparing healing rates between BioLIFT and LIFT is unknown. This study details the protocol for a systematic review and meta-analysis of BioLIFT and LIFT to compare outcomes associated with each procedure. METHODS AND ANALYSIS: MEDLINE, EMBASE and the Cochrane Database will be searched from inception using a search strategy designed by an information specialist. Randomised controlled trials, prospective and retrospective cohort studies, consecutive series, cross-sectional studies and case series with more than five patients will be included. Both comparative and single group studies will be included. The eligible population will be adult patients undergoing BioLIFT or LIFT for trans-sphincteric anal fistula. The primary outcome will be primary healing rate. Secondary outcomes will capture secondary healing rate and complications. Abstract, full text and data extraction will be completed independently and in duplicate by two reviewers. Study risk of bias will be assessed using Risk of Bias In Non-randomized Studies - of Interventions and the Risk of Bias (RoB 2.0) tool. Quality of evidence for outcomes will be evaluated using Grading of Recommendations, Assessment, Development and Evaluations criteria. A meta-analysis will be performed using a random-effects inverse variance model. Subgroup and sensitivity analyses will be explored in relation to complex fistula characteristics and patients who have undergone previous LIFT. Heterogeneity will be assessed using the I(2) statistic. ETHICS AND DISSEMINATION: This review does not require research ethics board approval. This study will be completed in September 2022. The findings of this study will be disseminated through peer-reviewed international conferences and journals. PROSPERO REGISTRATION NUMBER: CRD42020127996.