Significance of MRI in the treatment of perianal fistula.

OBJECTIVES Objective of the study was to examine patients with fistula preoperatively with MRI and then compare with operative findings. BACKGROUND Most common cause of perianal suppuration is infection of cryptoglandular origin. This results in simple intersphincteric abscess, or spreading of infection in cranial or caudal direction, horizontally or circulary. To choose the correct surgical therapy, sufficient diagnostic is necessary. This includes clinical examination, endorectal ultrasonography, rectoscopy with fistula injection with hydrogen peroxide or dye. More and more often MRI is used. METHODS In 2007 19 patients with perianal fistula were operated on. In 14 patients, preoperative MRI was done without contrast dye or probing. Fistulas were classified on 5-grade scale. We treated simple fistulas with fistulectomies, in three cases of complicated fistulas cutting setons were used. RESULTS We examined 14 patients and confronted preoperative MRI result with operative findings. In 12 patients results matched, in two patients peroperatively diagnosed and treated fistula did not show on MRI. One was transsphincteric fistula with abscess and one was simple transsphincteric fistula.Because of low number of patients, statistical interpretations are not significant. CONCLUSIONS Results are preliminary, we continue in prospective analysis. MRI may be useful for successful treatment by correct assessment of the extent of disease. It is necessary to consider cost-effectiveness when indicating MRI (Tab. 6, Fig. 3, Ref. 11). Full Text (Free, PDF) www.bmj.sk.