Surgical diversion of waste products can be done in 2 ways. Your surgeon may join the end of your small bowel to your anus. S/he also creates a pouch from the end of your small bowel, which will replace your colon and allows your bowel movements to carry on as usual. This is called a proctocolectomy and ileoanal pouch-it is the most common type of procedure for ulcerative colitis; or your surgeon may attach your small bowel to an opening in your abdomen. You then use an external pouch placed over the opening, called an 'ileostomy bag', to collect waste. This is called an ileostomy and is the traditional type of operation for ulcerative colitis.
Attribution: BUPA