Bone demineralization following ureterosigmoid anastomosis: an experimental study in rats.

This study was designed to examine the renal and bony metabolic responses to urinary diversion through intestinal segments. Twenty rats underwent urinary diversion by ureterosigmoidostomy and were compared to twenty control rats with respect to renal excretion of electrolytes and bone mineralization after a 10-week period. Ureterosigmoidostomy rats demonstrated increased renal excretion of ammonium, sulfate, magnesium, and possibly phosphorus. Bone calcium content was decreased in ureterosigmoidostomy rats, while bone phosphorus content was slightly increased. These changes occurred in the absence of systemic acid-base alterations. We are unable to demonstrate an increased renal loss of calcium in the ureterosigmoidostomy rats compared to controls. This suggests that decreased renal reabsorption of urinary calcium is not the primary pathophysiologic process involved in this problem.