Mucosal morphologic alterations in Thiry-Vella fistulas.

Three Thiry-Vella fistulas were surgically placed in each of 9 dogs to study the effects of x-irradiation on isolated loops of small intestine. Mucosal biopsy samples were removed from the fistulas for 5 days at 24-hour intervals after surgical operation to assess the morphologic alterations that occurred in the fistula mucosa following surgical isolation. There was a reduction of villus height during the 1st day, reduction of crypt depth on days 2 and 3, and stabilization of villus height and crypt depth during days 3 to 5 after surgical operation. The surgical technique and morphologic alterations observed in the mucosa of the fistulas during the 5 days after surgery are described.