P656 Epidemiology and outcomes associated with local surgical and intersphincteric ligation procedures for complex cryptoglandular fistulas: A systematic literature review

Iglay, K.(1);Bennett, D.(2,3);Kappelman, M.(4);Karki, C.(2);Cook, S.(1);

(1)CERobs Consulting, CERobs Consulting, Wrightsville Beach, United States;(2)Takeda Pharmaceuticals USA- Inc, Global Evidence and Outcomes, Cambridge, United States;(3)Perelman School of Medicine, University of Pennsylvania, Philadelphia- PA, United States;(4)Chapel Hill School of Medicine- University of North Carolina, Pediatric Gastroenterology, Chapel Hill, United States


Studies suggest that complex cryptoglandular fistulas (CCF) are difficult to treat, resulting in higher intervention failure rates and functional disability. This systematic literature review (SLR) assessed the epidemiology of cryptoglandular fistula and outcomes associated with local, surgical and intersphincteric ligation procedures for treatment of CCF.


PubMed and Embase were searched to identify articles published in the past 5 years (2015-2020) relating to incidence or prevalence of cryptoglandular fistula and outcomes of surgical interventions for CCF (PROSPERO registration number CRD42020177732). Outcomes of interest included fistula closure/healing, recurrence, surgery failure, post-operative pain and faecal incontinence. The interventions included anal flap procedures, fistulectomy, fistulotomy, primary sphincteroplasty, modified Park’s technique, LIFT or BIOLIFT, and TROPIS. Two trained reviewers used pre-specified eligibility criteria to identify studies for inclusion and evaluate risk of bias using the Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool for observational studies. Data were extracted for a range of variables, including study type and design, population, outcomes and limitations.


In total, 148 studies were identified that met a priori eligibility criteria for all cryptoglandular fistulas and all intervention types. Of these, two reported incidence or prevalence of cryptoglandular fistulas and 18 reported outcomes for the interventions of interest in CCF. Prevalence of cryptoglandular fistulas was reported as 1.35 per 10 000 patients without Crohn’s disease, and 52.6% of patients without IBD were found to progress from anorectal abscess to fistula over 12 months. Studies examining the clinical outcomes reported primary healing rates of 57.4–100.0%, recurrence rates of 4.9–61.0% and failure rates of 2.8–18.0% of patients. Only five studies reported post-operative pain as a clinical outcome. Overall, these studies suggest patients experience no or minimal longer-term post-operative pain. In studies reporting post-operative faecal incontinence following anal mucosal flap procedures, observed incontinence rates were low, as measured using Wexner or Miller scoring. None of the studies involving fistulectomy measured faecal incontinence.


This SLR provides a summary of outcomes from a selected group of surgical interventions for CCF. Healing rates vary according to surgery type; however, differences in study design and heterogenous definitions prevent direct comparison. Overall, the published literature indicates low to modest rates of CCF recurrence and limited data on faecal incontinence and longer-term post-operative pain.

Sponsor: Takeda Pharmaceuticals USA, Inc.