Anal endosonography and fistulography for fistula-in-ano

Purpose. In this study, a comparison was made of the accuracy and clinical usefulness of anal endosonography and fistulography in the preoperative classification of fistulas-in-ano. Materials and methods. A total of 113 patients with a clinical diagnosis of cryptoglandular fistula-in-ano who were awaiting surgery were included in this retrospective review. Patients were preoperatively investigated by anal endosonography and/or modified fistulography by inserting a Foley catheter into the rectum and a metal ring close to the anus. The catheter and ring served as radiopaque anal markers. Fistula classification obtained by the two diagnostic modalities was compared with surgical classification as the criterion standard. Results. Endoanal ultrasound and fistulography identified 82.8% and 100% of primary tracks, 79% and 74.2% of internal openings, 98% and 91.8% of secondary tracks and 92.9% and 87.8% of abscesses, respectively. Conclusions. Anal endosonography and fistulography with radiopaque markers are important complements to surgical exploration for investigating anal sepsis and may be of value to the surgeon in planning a therapeutic strategy.