The Cost of Imperfection: Recurrence‐Adjusted Costs of Sphincter‐Preserving Procedures for Complex Anal Fistula in Australia

BACKGROUND: Complex cryptoglandular anal fistula is frequently complicated by treatment failure, repeat intervention and ongoing healthcare use. Economic evaluations are limited, rarely incorporate failure-related re-intervention, and seldom distinguish between public and private settings. This study compared 12-month pathway costs for ligation of the inter-sphincteric fistula tract (LIFT), endorectal advancement flap (ERAF), video-assisted anal fistula treatment (VAAFT) and non-definitive seton management in Australia. METHODS: A micro-costing analysis was performed using 2023-24 Australian public and private hospital data. Costs were calculated from the hospital perspective and incorporated procedures required after treatment failure over 12 months, reflecting pathway costs rather than index procedure costs. Failure rates and re-intervention pathways were derived from a prospectively maintained cohort treated within a single colorectal surgical network (LIFT n = 88; ERAF n = 16; VAAFT n = 22). Non-definitive seton management was modelled as one, two or four planned operative episodes per year. RESULTS: Crude observed 12-month treatment failure was similar across definitive procedures (LIFT 36%, ERAF 38%, VAAFT 36%). Pathway costs incorporating treatment failure were AUD 1846/8858 for LIFT, AUD 2161/9164 for ERAF, and AUD 1937-2968/8870-10 499 for VAAFT in public/private hospitals, depending on case volume. Seton management cost AUD 871-3484/5050-20 200 per year, depending on operative frequency. CONCLUSION: Incorporating treatment failure narrowed cost differences between definitive sphincter-preserving techniques. Non-definitive seton costs were frequency-dependent. Local case volume, admission pathway, and failure burden should inform service planning and VAAFT adoption.