EP978 - Three-cavity clearance significantly reduces the rate of anal fistula formation and abscess recurrence after perianal abscess: a single-center real-world study

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Purpose/Background: To analyze the effectiveness and safety of three-cavity clearance (TCC) in the treatment of glandular perianal abscess based on real world data, explore the risk factors of recurrence and anal fistula after TCC, and construct a nomogram risk model. To further improve the success rate of TCC for perianal abscess.

Methods/Interventions: The clinical data of patients who underwent TCC of perianal abscess at The Second Affiliated Hospital of Nanjing University of Traditional Chinese Medicine from January 2018 to January 2024 were collected. The patients were divided into the good healing group and complication group according to whether they had recurrence or formed an anal fistula after the operation. The collected data included the patients' gender, age, disease duration, history of perianal abscess operation, coexisting diseases, location of abscess, hospitalization time, operation time, wound healing time, rate of anal fistula formation, rate of abscess recurrence, and incontinence. The factors affecting the recurrence and formation of anal fistula after TCC were analyzed by univariate and multivariate logistic regression analysis. The independent risk factors were used to construct a risk model for predicting the occurrence of anal fistula after TCC using the ROC curve and calibration curve for model consistency and discriminatory power verification.

Results/Outcomes: From January 2018 to January 2024, a total of 308 patients were included, with an average follow-up time of 37.9±16.8 months. The formation rate of anal fistula was 5.5%, the recurrence rate of abscess was 7.5%, and one patient presented with occasional fluid leakage after the operation, with a Wexner score of 1 point, and the total effective rate was 87.0%. In the postoperative complication group of TCC, the proportions of patients with a history of abscess surgery, diabetes mellitus, deep abscess, longer hospitalization time, and longer healing time were higher than those in the good healing group (p < 0.05). The results of multivariate logistic regression analysis indicated that a history of abscess surgery, diabetes mellitus, deep abscess, and longer healing time were independent risk factors for recurrence and formation of anal fistula after abscess surgery (p < 0.05). The nomogram model revealed that a history of abscess surgery added a weight of 43.1 points, diabetes mellitus added a weight of 78 points, deep abscess added a weight of 100 points, and longer healing time added a weight of 38.5 points. The constructed nomogram model was verified using the Bootstrap method. The results demonstrated that the ideal curve of the nomogram model fitted well with the calibration curve. The area under the ROC curve was 0.855 (95% CI=0.79-0.92), and the specificity and sensitivity were 82.55% and 77.5%, respectively, indicating that the nomogram model had good predictive discrimination.

Conclusion/Discussion: TCC has an advantage in reducing the incidence of postoperative anal fistula and abscess recurrence, protecting the function of anal sphincter, and having obvious long-term effects. It is a safe and effective surgical method. The history of abscess surgery, coexisting diabetes, deep abscess, and longer healing time are the influencing factors for the recurrence of perianal abscess and the formation of star-shaped anal fistula after operation. They can guide clinical screening of high-risk groups and control variable risk factors to further improve the success rate of the three-cavity clearance of perianal abscess.