Background and Study Aims: Outcomes following surgical treatment of patients with anal fistula are related to
eradication of tracts and the internal opening. In this study, the results of surgery
based on endoanal ultrasound (EAUS) findings were evaluated.
Patients and Methods: A total of 102 patients with primary cryptogenetic anal fistula were prospectively
examined with EAUS, using a 360-degree rotating 10-MHz probe, equipped with a three-dimensional
(3-D) imaging system. Injection of hydrogen peroxide through the external opening
was also used. Patients underwent operation on the basis of the EAUS findings. The
agreement between findings from EAUS and from surgery was calculated. Clinical results
were reported as treatment success, fistula recurrence, and fecal incontinence.
Results: Amongst 102 patients, the overall concordance between EAUS and surgical findings
was 94.1 % for primary tracts, 91.2 % for internal openings, 96.1 % for secondary
tracts, 100 % for abscesses, and 96.1 % for horseshoe tracts. Diagnostic accuracy
was improved when hydrogen peroxide injection or 3-D imaging were used. Fistulotomy
was performed in 46 patients (45.1 %), fistulectomy in 17 (16.7 %), fistulotomy plus
seton placement in 19 (18.6 %), fistulectomy plus seton in 18 (17.6 %), and mucosal
flap advancement in 2 (2.0 %). The operation was curative in 100 patients (98.0 %),
and unsuccessful in 2 (2.0 %) due to recurrence of the fistula. Fecal continence was
preserved in all patients.
Conclusions: These data highlight the diagnostic accuracy of EAUS, particularly when hydrogen
peroxide injection or 3-D imaging are used. Basing our surgical decision making on
EAUS findings allowed us to carry out curative operations in a significantly large
number of patients; the recurrence rate was very low. The accurate EAUS assessment
of the relationship between fistulas and sphincters has been the main factor in choosing
a sphincter-saving surgical procedure, avoiding fecal incontinence.
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C. Ratto, M. D.
Department of Surgical Sciences, Catholic University
Largo A. Gemelli 8 · 00168 Rome · Italy
Fax: +39-06-6693413
Email: carloratto@tiscali.it
