Anal Fistula in Crohn's Disease

Lim, Seok Won; Lee, Chul Ho; Lee, Kwang Real; Yu, Jung Jun

Abstract

Crypt glandular infection theory is accepted as an explanation of anal fistula's major cause. However, the pathogenesis of an anal fistula in Crohn's disease is different from that of a conventional anal fistula because a Crohn's anal fistula is caused by ulceration which, in turn, is caused by transmural inflammation of the rectal wall due to Crohn's disease. The difficulty with operating on anal fistulas in Crohn's disease lies in the fact that healing of the wound is inhibited because of continuous inflammation of the anorectal tissue due to Crohn's disease. Hence, there is a high possibility of incontinence due to sphincter muscle injury. Especially, because almost all Crohn's disease patients have frequent defecation and diarrhea, the patients will suffer more if incontinence occurs. Nowadays, even with increased understanding of the etiology of Crohn's disease, new medications, and aggressive surgical approaches, the result of treatment is still not satisfactory. Recently, since Korean eating habits have changed to include more western-style food in the diet, inflammatory bowel disease, such as Crohn's disease, is expected to increase. Consequently, the number of cases of anal fistulas in Crohn's disease is also expected to increase. The authors reviewed 20 confirmed cases of anal fistulas in Crohn's disease, which were treated from January 1993 to December 1995 at Song-Do Colorectal Hospital. The results are as follows: 1) Anal fistulas in Crohn's disease were present in 20(0.6%) of the 3378 cases of anal fistulas treated during the time period considered. 2) The male to female ratio for these 20 cases was 2: 1, and the most Prevalent age group was the 3rd decade, followed by the 2nd decade, the 4th decade, and the 5th decade in that order. 3) Three cases of anal fistulas whose origins could be explained by crypt glandular infection theory and which did not involve the rectum healed, although the healing was delayed. 4) Seventeen cases of anal fistulas whose origins could not be explained by crypt glandular infection theory and which involved the rectum did not heal after the operation. he results of the study show that anal fistulas whose origins can be explanined by crypt glandular infection theory and which do not involve the rectum can be cured by conventional fistula surgery. However, perirectal fistulas whose origins can not be explained by crypt glandular infection theory and which involve the rectum do not heal. Because there is the possibility of incontinence after a conventional operation, it is suggested that, in the cases of perirectal fistulas in Crohn's disease, better results, although not completely satisfactory, can be obtained by long-term seton drainage and diversion colostomy.