Is anal endosonography useful in the study of recurrent complex fistula-in-ano?

Abstract

Introduction: performing anal endosonography in complex fistula-in-ano allows us to design a personalized surgical strategy in each case, thereby improving results. However, there are doubts in the literature as to its utility in recurrent complex fistulas. The aim of this study was to compare the utility of anal ultrasonography in the study of primary versus recurrent complex fistula-in-ano. Patients and method: prospective study of patients diagnosed and treated for complex fistula-in-ano. Physical examination and anal ultrasonography provided data on primary track, internal opening, horseshoe extension and the presence of secondary tracks or cavities in a protocol designed specifically for the study. These assessments were subsequently contrasted with operative findings. Results: we included 35 patients, 19 (54.3%) with primary complex anal fistulas and 16 (45.7%) with recurrent fistulas. According to the operative findings, fistulas were classified as high transsphincteric in 28 patients (80%), suprasphincteric in 6 (17.1%) and extrasphincteric in one patient (2.9%), with no differences between groups. Physical examination correctly classified 28 of the 35 fistulous tracks, in contrast to the 32 (91.4%) correctly described on ultrasonography (80%). We did not find any statistically significant differences between the primary and the recurrent fistula groups with regard to sensibility, positive predictive value and accuracy of the anal ultrasonography for any of the parameters studied. Conclusion: the accuracy of anal ultrasonography does not decrease in recurrent complex fistula-in-ano.

Keywords

• anal ultrasonography
• complex fistula-in-ano
• accuracy