The Efficacy of Transanal Ultrasonography in Fistula In Ano

Kim, Jin Cheon; Jeong, Choon Sik; Kim, Hee Cheol; Kim, Chang Nam; Park, Sang Kyu; Kim, Sook Young; Yu, Chang Sik

Abstract

BACKGROUND: Successful treatment of a fistula in ano (FIA) depends on identifying track of the fistula and the internal opening at the time of surgery as well as on eradicating them by appropriate surgery. Transanal ultrasonography (TUS) has been known to be an useful tool for the evaluation of anorectal inflammatory lesion, such as perianal abscess and FIA. Preoperative TUS was performed to determine the accuracy in respect to detection the of fistula track and the internal opening.
METHODS
One hundred nineteen patients were examined by preoperative TUS among 176 patients with FIA treated from January 1996 to December 1997. TUS findings were compared with operative findings in respect to location of track, types and primary opening of the fistula. TUS was performed by using the Scanner type 2001 with an attached endoprobe.
RESULTS
The track of fistula on preoperative TUS was identified in 119 cases, and TUS findings were not identical with operative findings in 14 cases. The accuracy of determining the fistula track was 88.2%. The most common type of fistula and the location of primary opening were intersphincteric type (53.0%) and posterior aspect (52.7%) respectively. The accuracies were 95% in intersphincteric type, 90.5% in transsphincteric type, 90% in suprasphincteric type and 62.5% in extrasphincteric type. Accurate identification of the internal opening was possible in 91 of the 119 cases. External sphincter damage was identified in 3 cases, and all of them were treated by sphincteroplasty at the time of surgery.
CONCLUSIONS
TUS is an accurate and minimally invasive method to identify the fistula track in relation to the anal sphincters and internal opening.