The role of transperineal ultrasonography in the assessment of the internal opening of cryptogenic anal fistula.

PURPOSE: The aim of this study was to assess the reliability of transperineal ultrasonography (TPUS) in the pre-operative identification of the internal opening of anal fistulas compared to conventional proctological examination and operative findings. METHODS: Forty-three patients with anal fistula were assessed by TPUS with and without the use of hydrogen-peroxide injection (E-TPUS) in an attempt to identify the internal opening. Results were compared to preoperative conventional examination and operative findings. RESULTS: Operative assessment showed an anterior internal opening in 29 patients (67.4%) and a posterior opening in 14 (32.6%). Compared to the operative findings, the agreement rate for the identification of the internal opening was 74.4% for physical examination alone, 93.0% for TPUS and 90.7% for E-TPUS. Physical examination was less accurate in detecting the internal opening than both TPUS (p=0.014) and E-TPUS (p=0.026). CONCLUSIONS: TPUS and E-TPUS are superior to physical examination in the identification of internal openings in anal fistulas. Hydrogen peroxide injection does not provide additional advantages.

Transperineal ultrasonography: new method to image the anorectal region.

PURPOSE: The aim of this preliminary study was to present an alternative method to assess the anal sphincters by ultrasonography using a conventional ultrasound surface probe by transperineal approach. METHODS: Transperineal ultrasonography was performed in 20 asymptomatic volunteers to assess the anal sphincters. Ultrasonographic findings were compared with conventional anal endosonography pictures available in the literature. RESULTS: Images of the anal sphincters obtained by transperineal ultrasound were found to be similar to those produced by conventional anal endosonography. Internal and external anal sphincters were easily demonstrated in addition to mucosal and submucosal layers. CONCLUSIONS: Transperineal ultrasonography is a new technique that enables imaging of anal sphincters and anal canal structures with potential application in functional and inflammatory anorectal disorders.