In some instances, surgery becomes necessary only after many years of disease, usually as a result of progressive scarring leading to repeated episodes of partial blockages. In general, postoperative recurrences tend to appear more rapidly in these aggressive cases. Postoperative recurrence of Crohn's disease is almost always located at the site of anastomosis, where the remaining ends of relatively normal intestine have been reconnected. If the original disease was in the small intestine alone, the recurrence usually occurs on the small bowel side of the anastomosis. In cases of ileostomy, the recurrences are nearly always located at the end of the small bowel right up to and including the ileostomy itself.
Some recurrences affect only an inch or two of the intestine.
Others may extend for many feet up and down the intestinal tract. But once a recurrence has taken place, it usually does not spread to other sections of the bowel, if no further surgery is performed. There is also a tendency of the recurrent disease to mimic the pattern of the disease before surgery. Another general characteristic of recurrent Crohn's disease after surgery is that it often proves more responsive to medical therapy than did the original disease. Nothing is guaranteed.