Total fistula volume predicts surgical outcomes in complex perianal fistulizing Crohn's disease following fistula-tract laser closure: a single-center retrospective study.

Backgrounds: This study aimed to identify risk factors influencing long-term treatment outcomes in patients with complex perianal fistulizing Crohn's disease (pfCD) following fistula-tract laser closure (FiLaC™).

Methods: A retrospective analysis was conducted on data from patients with complex pfCD who underwent FiLaC™ from January 2019 to December 2020, including demographics, pharmacological regimens, and preoperative MRI assessments. Follow-up monitored fistula outcomes such as healing, remission, failure, and recurrence.

Results: Among 49 patients followed for an average of 60.0 months, 31 (63.3%) achieved fistula healing, 3 (6.1%) showed improvement, 3 (6.1%) had non-healing, and 12 (24.5%) experienced recurrence. Significant differences were found between healed and unhealed groups in total fistula volume (TFV), number of fistula tracts, and perianal Crohn's disease activity index (PDAI) (P = 0.036, P = 0.020, and P = 0.041, respectively). Multivariate regression analysis indicated TFV as a significant predictor of healing outcomes (P = 0.013). ROC analysis confirmed its predictive value for fistula healing in complex pfCD, with an area under the curve (AUC) of 0.729 (P = 0.008). The optimal threshold for TFV was 4.81 cm, with a sensitivity of 61.1% and a specificity of 83.9%. The AUC for recurrence rates was 0.883 (P < 0.001), with sensitivity and specificity at 83.3% and 83.8%, respectively, using the same threshold for TFV. The Kaplan-Meier survival curve highlighted the predictive potential of TFV for fistula recurrence (P < 0.0001).

Conclusions: TFV is an effective predictor of long-term outcomes in patients with complex pfCD following FiLaC™.