[Usefulness of anal endosonography in the assessment of fistula-in-ano].

AIM: The purpose of the present study was to define the diagnostic value of anal endosonography in the diagnostic work-up of fistula-in-ano.

METHODS

A retrospective study was carried out on 191 consecutive patients (m: 121; f: 70; mean age: 44.0 +/- 12.5 years; range: 0.5-77 years) who were diagnosed to suffer from fistula-in-ano by performing anal endosonography in an outpatient setting. All images were obtained with a Combison 310A ultrasound scanner (Kretz GmbH, Zipf, Osterreich) and 5-Mhz and 7.5-MHz transducer. 131 patients underwent surgery. According to the endosonographic findings fistulas were classified as transsphincteric in 44 %, intersphincteric in 22 %, subanodermal in 16 %, anovaginal in 8 %, suprasphincteric in 5 %, extrasphincteric in 1 % and others in 4 %.

RESULTS

In 125 patients (95 %) the preoperative diagnosis was confirmed intraoperatively. This cohort included 12 patients with a complex fistula system. In only 6 patients the preoperative ultrasound finding was misinterpreted.

CONCLUSION

In conclusion this study has shown that anal endosonography is a useful and reliable tool in the preoperative evaluation of uncomplicated and complicated anorectal fistulas.