Fistula in Ano After Incision and Drainage of Perianal Abscess

Abstract

Background: Perianal abscess is a common manifestation of anorectal sepsis and is frequently managed with surgical incision and drainage; however, persistence of cryptoglandular infection may lead to fistula-in-Ano, a chronic condition associated with recurrent discharge, discomfort, and the need for further surgical intervention. Objective: To determine the incidence of fistula-in-Ano following incision and drainage of perianal abscess and to evaluate clinical factors associated with its development in patients treated at a tertiary care hospital. Methods: A hospital-based descriptive cross-sectional observational study was conducted in the Department of General Surgery at Bolan Medical Complex Hospital, Quetta, from January to June 2025. A total of 116 adult patients aged 20–50 years who underwent incision and drainage for clinically diagnosed perianal abscess were included using consecutive sampling. Demographic data, abscess characteristics, and postoperative outcomes were recorded using a standardized proforma. Patients were followed for six months to identify fistula development. Statistical analysis was performed using SPSS version 26 with chi-square testing and logistic regression to evaluate associations. Results: Fistula-in-Ano developed in 28 of 116 patients (24.1%) during follow-up. Larger abscess size (≥3 cm) was significantly associated with fistula formation (33.3% vs 16.1%, OR 2.81, p = 0.021), as was deeper abscess involvement (39.1% vs 14.3%, OR 3.47, p = 0.007). Intersphincteric fistulas were the most common type (67.9%). Surgical management achieved a 75% healing rate with minimal recurrence. Conclusion: Fistula-in-Ano occurs in approximately one-quarter of patients following incision and drainage of perianal abscess, with abscess size and depth serving as significant predictors. Early recognition and appropriate surgical management are essential for improving outcomes and reducing disease-related morbidity.