A Retrospective Critique of the Various Sphincter-preserving Surgical Procedures for Ischiorectal Fistula

In the 1950s, the cause of anal fistulas was identified as an infection of the anal gland (cryptoglandular infection theory). Thereafter, treatment for this disorder began in the 1960s with the lay-open procedure, which involved incising the sphincter and the fistula tract. However, it was found that too much invasion into the sphincter could result in postoperative fecal incontinence. Thus, to reduce such risk, sphincter-preserving surgery was applied for superficial anal fistula in 1961 and for deep anal fistula (ischiorectal fistula) in 1965. Over the years, more effective sphincter-preserving procedures for ischiorectal fistula have been developed to improve the quality of life of the patient. In this review article, we aim to first introduce the basic surgical techniques for ischiorectal fistula. We will discuss the anatomy of the anus and the pathogenesis of ischiorectal fistula and will provide some diagnostic methods. Representative sphincter-preserving procedures that have been performed for ischiorectal fistula since 1965 will also be categorized and outlined chronologically. The discussion will look at the following techniques for ischiorectal fistula and outline the advantages and disadvantages of each procedure so that they can be used as a reference for ischiorectal fistula surgery in the future: the lay-open procedure (fistulotomy and fistulectomy), the Hanley procedure (first partial sphincter-preserving procedure), the muscle-filling procedure, the Moriya method and Ui method (modified partial sphincter-preserving procedure), the Takano method and the sphincter-preserving lateral procedure (complete sphincter-preserving procedure), the seton method (a cross between the lay-open procedure and sphincter-preserving procedure), and the overseas sphincter-preserving procedure.