Question 1863
{"accessible":false,"alternatives":[{"id":9253,"text":"extrasphincteric "},{"id":9254,"text":"intersphincteric"},{"id":9255,"text":"suprasphincteric "},{"id":9256,"text":"transsphincteric "}],"archived":false,"correctAlternativeId":9254,"explanation":"\u003cp\u003eThe\u0026nbsp;\u003cstrong\u003eParks classification\u003c/strong\u003e\u0026nbsp;has become the most widely used surgical classification for distinguishing four types of fistula. The course of the fistula and its relationship to the\u0026nbsp;anal sphincters\u0026nbsp;is described in the coronal plane:\u003c/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eintersphincteric\u0026nbsp;\u003c/strong\u003e(~70%): fistula crosses the intersphincteric space and does not cross the external sphincter\u003c/li\u003e\n\u003cli\u003e\n\u003cstrong\u003etranssphincteric\u0026nbsp;\u003c/strong\u003e(25%):\u0026nbsp;fistula crosses from the intersphincteric space,\u0026nbsp;through the external sphincter, and into the\u0026nbsp;ischiorectal fossa\u003c/li\u003e\n\u003cli\u003e\n\u003cstrong\u003esuprasphincteric\u0026nbsp;\u003c/strong\u003e(5%):\u0026nbsp;\u0026nbsp;fistula passes superiorly into the intersphincteric space, and over the top of the\u0026nbsp;puborectalis muscle\u0026nbsp;then descending through the\u0026nbsp;iliococcygeus\u003ca href=\"https://radiopaedia.org/articles/levator-ani-muscle?lang=gb\"\u003e \u003c/a\u003emuscle\u0026nbsp;into the ischiorectal fossa and then skin\u003c/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eextrasphincteric\u0026nbsp;\u003c/strong\u003e(1%):\u0026nbsp;fistula crosses from the perineal skin through the ischiorectal fossa and\u0026nbsp;levator ani muscle complex\u0026nbsp;into the\u0026nbsp;rectum\u0026nbsp;(i.e. it is outside the external anal sphincter)\u003c/li\u003e\n\u003c/ul\u003e","id":1863,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/1863","nextQuestionPath":null,"relatedArticles":[{"id":9514,"title":"Perianal fistula","link":"/articles/perianal-fistula?lang=us"}],"alsoUsedIn":[],"stem":"\u003cp\u003eWhat is the most frequent perianal fistula according to the Parks surgical classification?\u003c/p\u003e","menuLinks":[{"text":"Report problem with question","url":"https://docs.google.com/forms/d/e/1FAIpQLSfO3soWYhOjJ7yErSysyCe5V4A1CqW7WK3rDA7MtAkecMGqNw/viewform?entry.1624461248\u0026entry.553583435=https://radiopaedia.org/questions/1863"}],"attemptsPercentages":[{"alternativeId":"9253","percentage":10},{"alternativeId":"9256","percentage":10},{"alternativeId":"9255","percentage":7},{"alternativeId":"9254","percentage":73}],"promptToLogin":false,"questionManager":false,"articleId":"perianal-disease"}