Coring-out fistulectomy for perianal cryptoglandular fistula: a retrospective cohort study on 20 years of experience at a single center.

Purpose: Cryptoglandular fistula is one of the common anal diseases requiring surgical treatment. Various surgical techniques have been introduced; however, there is no known standard technique. Coring-out fistulectomy is a surgical technique that accurately resects only the fistula tract. However, only a few cases of this procedure have been reported. We aimed to analyze the surgical outcomes of coring-out fistulectomy for cryptoglandular anal fistulas. Methods: We retrospectively reviewed the medical records of patients who underwent coring-out fistulectomy for a cryptoglandular fistula between 1999 and 2019. Primary outcomes were the treatment success rate (recurrence and healing rates) and incidence of fecal incontinence. Results: A total of 184 patients were included in our study. The average age of the patients was 44 years (range, 16-75 years), and 88.0% were male. Twenty-four (13.0%), 13 (7.1%), and 68 patients (37.0%) underwent operation for recurrent fistula, multiple tracts, and complex type fistula, respectively. The healing rate was 92.4%, and recurrence occurred in 15 of 170 healed patients (8.8%). Thus, the treatment success rate was 84.2%. There was no fecal incontinence except in 1 patient who had preoperative fecal incontinence because of cauda equine syndrome. In multivariable analysis of the factors affecting the treatment success rate, the complex fistula (odds ratio [OR], 14.2; 95% confidence interval [CI], 4.7-43.0; P < 0.001) and undetected internal opening during the operation (OR, 4.0; 95% CI, 1.4-11.6; P = 0.012) were significant factors. Conclusion: Coring-out fistulectomy is a simple and feasible technique for sphincter-preserving anal fistula surgery.