Background: To identify the risk factors of converting from video-assisted anal fistula treatment (VAAFT) to seton fistulotomy. Materials and Methods: A total of 180 patients registered to undergo VAAFT between January 2016 and June 2020 at the Erlonglu Hospital. Intraoperative examination of the fistula tract revealed that the patients were assigned to undergo the VAAFT operation and seton fistulotomy. Results: Among 180 patients aged 37 (±10.4) years who underwent intraoperative examination of the fistula tract, 101 completed the standard VAAFT and 79 converted to seton fistulotomy. Univariate analyses revealed that age, necrotic cavity diameter ≥1 cm, scars at the anal entrance, tissue edema, Parks classification, fistula stenosis, and fistula branches were significantly different between the VAAFT and converted groups (P < .05). Multivariate analysis revealed a significant correlation between the risk of surgery conversion and the presence of necrotic cavity with a diameter of ≥1 cm (odds ratio [OR]: 3.668, 95% confidence interval [CI]: 1.366-9.853, P = .01), scars at the anal entrance (OR: 9.462, 95% CI: 1.562-57.32, P = .014), fistula stenosis (OR: 25.14, 95% CI: 5.211-121.3, P < .001), and fistula branches (OR: 2.90, 95% CI: 1.088-7.73, P = .033). The nomogram based on the logistic model was fitted with high accuracy and area under curve of 0.793 (95% CI: 0.726-0.861). Conclusions: The independent risk factors of conversion from surgery for VAAFT to seton fistulotomy were the presence of necrotic cavity with a diameter of ≥1 cm, scars at the anal entrance, fistula stenosis, and fistula branches. The protocol of this systematic review was registered a priori in the Chinese Clinical Trial Registry (ChiCTR) under the registration number of ChiCTR1900022810.
Keywords: VAAFT; prediction model; rectal fistula; risk factor.