Reliability of endosonography in evaluation of anal fistulae and abscesses

Objective: To assess the reliability of anal endosonography (AES) in the diagnosis of anal fistulae and abscesses. Material and Methods: 86 patients with different types of anal fistulae and abscesses were prospectively examined with a 7.0 MHz transducer. Type of anal fistulae, differentiation between simple and complex tracts, and location of their internal openings were defined. In 66 cases with permeable external opening, hydrogen peroxide solution was introduced into the fistula tract. Reliability of AES was defined after surgical treatment of all cases. Results: 74 anal fistulae, including 43 transsphincteric, 11 intersphincteric, 6 suprasphincteric, 3 superficial, and 11 ano-vaginal were found on AES. 27 fistulae were complex, and 47 simple fistulae. In 10 patients a coexisting abscess was found; the remaining 12 abscesses were without any fistula. Surgery confirmed the type of anal fistula in 64 patients (86.5%), and location of internal openings in 60 cases (81.1%). All abscesses were confirmed. Conclusion: AES showed high accuracy in diagnosing anal fistulae and abscesses.