豊永敬之の痔瘻に対する肛門管超音波検査・エコー検査・オキシドール造影の論文 Copy of 福岡の大腸・肛門科専門医による痔・肛門科・大腸内視鏡（大腸カメラ）のサイト　大腸肛門武者修行

Purpose: This study was undertaken to evaluate the accuracy of endoanal ultrasonography for preoperative assessment of anal fistula, with special reference to the difference between acute and chronic fistula.
Patients and methods: Subjects were 401 patients treated for acute or chronic anorectal sepsis of cryptoglandular origin during the period January through December 2005. All patients underwent physical examination and endoanal ultrasonography. Agreement of the physical and endosonographic findings with definitive surgical findings were evaluated with special reference to classification of the primary tract and horseshoe extension and localization of the internal opening. The difference of accuracy of endosonographic assessment between acute and chronic fistula was also evaluated.
Results: Accuracy of endoanal ultrasonography was significantly higher than that of physical examination in detecting the primary tract (88.8% vs. 85.0%, P = 0.0287) and horseshoe extension (85.7% vs. 58.7%, P < 0.0001) and in localizing the internal opening (85.5% vs. 69.1%, P < 0.0001). Furthermore, localization of the internal opening by endosonography was significantly more accurate in cases of chronic fistula than in cases of acute fistula (89.5 % vs. 76.8%, P < 0.0001), although accuracy in detecting the primary tract and horseshoe extension was not significantly different.
Conclusions: Endoanal ultrasonography is reliable and useful for preoperative assessment of anal fistula, particularly for detecting horseshoe extension and localizing the internal opening. Endosonographic assessment provides clearer depiction of the internal opening during periods of quiescence than during the period of abscess formation. For patients with acute anorectal sepsis, initial surgical drainage and subsequent fistula surgery, rather than one-stage fistula surgery, may be advisable for avoiding misidentification of the internal opening.