Seeing the Unseen Tracts: “The Role of MRI in Recurrent Fistula-in-Ano Surgery”- A Case Control Study

Background: Surgery for recurrent fistula-in-ano is associated with higher rates of recurrence compared to index cases. Accurate delineation of fistula tracts using preoperative magnetic resonance imaging (MRI) fistulogram may improve outcomes. Aim: To compare recurrence outcomes in patients undergoing surgery for recurrent fistula-in-ano with and without preoperative MRI fistulogram. Methods: A case–control study was conducted on patients who underwent surgery for fistula-in-ano between May 2024 and December 2025. The cases were patients who underwent surgery with preoperative MRI fistulogram, and controls were those operated without an MRI fistulogram before May 2024. Data for cases were collected prospectively, whereas controls were identified retrospectively and followed prospectively. The primary outcome was recurrence rate. The effect size was based on previous literature suggesting up to a 75% reduction in recurrence with MRI-guided surgery. Results: Among total cases (n=75), recurrence rates augmented with fistula grade, ranging from 15.7% (Grade 3) to 33.3% (Grade 5), with an overall recurrence of 20% (15/75). In controls (n=75), recurrence rates ranged from 35.7% (Grade 3) to 60% (Grade 5), with an overall recurrence of 45.3% (34/75). The difference was statistically significant (p < 0.001). Conclusion: Preoperative MRI fistulogram significantly reduces recurrence in recurrent fistula-in-ano, particularly in higher-grade fistulas where clinical examination under anesthesia may be inadequate.