BACKGROUND: The aim of this study was to evaluate the accuracy of hydrogen peroxide-enhanced ultrasound in localizing the internal opening of the anal fistula. METHODS: A retrospective review of all patients with anal fistula who underwent hydrogen peroxide-enhanced ultrasound was performed. The results of hydrogen peroxideenhanced ultrasound and intraoperative findings on the basis of operative reports were correlated. RESULTS: A total of 57 patients (47 men) of mean age of 45.7 (range, 21-77) years underwent hydrogen peroxide-enhanced ultrasound with a diagnosis of anal fistula; 36 patients underwent surgery. The intraoperative internal opening correlated with the hydrogen peroxide-enhanced ultrasound report in 22 of 36 patients (61.1%). In 5 patients, the hydrogen peroxide-enhanced ultrasound yielded false-positive information with a positive predictive value of 84%. Four of the 7 patients with falsenegative hydrogen peroxide-enhanced ultrasound findings had supra- and extrasphincteric fistulas. CONCLUSIONS: There is a 61.1% correlation between hydrogen peroxide-enhanced ultrasound and surgical findings of the internal opening with a positive predictive value of 84%. If no internal opening was seen on hydrogen peroxide-enhanced ultrasound, it strongly suggests the possibility of a supralevator or extrasphincteric fistula.
BACKGROUND: The aim of this study was to evaluate the accuracy of hydrogen peroxide-enhanced ultrasound in localizing the internal opening of the anal fistula. METHODS: A retrospective review of all patients with anal fistula who underwent hydrogen peroxide-enhanced ultrasound was performed. The results of hydrogen peroxideenhanced ultrasound and intraoperative findings on the basis of operative reports were correlated. RESULTS: A total of 57 patients (47 men) of mean age of 45.7 (range, 21-77) years underwent hydrogen peroxide-enhanced ultrasound with a diagnosis of anal fistula; 36 patients underwent surgery. The intraoperative internal opening correlated with the hydrogen peroxide-enhanced ultrasound report in 22 of 36 patients (61.1%). In 5 patients, the hydrogen peroxide-enhanced ultrasound yielded false-positive information with a positive predictive value of 84%. Four of the 7 patients with falsenegative hydrogen peroxide-enhanced ultrasound findings had supra- and extrasphincteric fistulas. CONCLUSIONS: There is a 61.1% correlation between hydrogen peroxide-enhanced ultrasound and surgical findings of the internal opening with a positive predictive value of 84%. If no internal opening was seen on hydrogen peroxide-enhanced ultrasound, it strongly suggests the possibility of a supralevator or extrasphincteric fistula.
Authors: T Toyonaga; Y Tanaka; J F Song; R Katori; N Sogawa; H Kanyama; T Hatakeyama; M Matsushima; S Suzuki; R Mibu; M Tanaka Journal: Tech Coloproctol Date: 2008-08-05 Impact factor: 3.781