Ultrasonography Accuracy for Perianal Fistula Anatomy

Endorectal ultrasonography is a diagnostic modality for evaluation of perianal pathologies and suitable surgical planning, especially in perianal fistula, due to its close relation to the anal sphincter complex. Detection of anatomical location of fistula tract and abscess is critical to select the best procedure. This study tries to demonstrate the accuracy of endorectal ultrasonography in mixed group of patients in diagnosing perianal fistula during two years, retrospectively. After Ethics Committee approval, all endorectal ultrasonography reports of all patients with perianal fistula referred to Shiraz Endorectal Ultrasonography Clinic of Shiraz colorectal research center between 2010 and 2012 were gathered. All endorectal ultrasonographies in this center was perform by a colorectal surgeon with BK Medical Class I type B Ultrasonography scanner with 12 MHz probe. Finally, 183 cases of perianal fistula were enrolled in the study. Operation notes were evaluated and the type of fistula was compared with ultrasound findings. This study showed that endorectal ultrasonography has adequate accuracy with 97.92% sensitivity and acceptable 89.53% specificity in diagnosis of perianal fistula. Compared with other reports, it seems that endorectal ultrasonography is an acceptable diagnostic tool for detecting perianal fistula compared with other diagnostic modalities. Endoanal sonography would be one of the high sensitive modalities for evaluation of perianal fistula. Detection of anatomy of fistula helps surgeon to choose best method for surgery.