Absorption and urinary excretion of oxalates following massive small bowel resection and colon interposition in rhesus monkeys.

The pattern of oxalate uptake in various segments of the bowel has been studied after 80% small bowel resection and antiperistaltic colon interposition in Rhesus monkeys. The levels of urinary oxalate excretion were significantly raised in the immediate postoperative period, with progressive reduction at six and 12 months. None of the animals developed renal calculi. The possible benefit of the colon interposition after massive small bowel resection, in the prevention of hyperoxaluria and urolithiasis is suggested. Improvement in the fat malabsorption, formation of insoluble calcium oxalate in the bowel lumen, leading to reduced net intestinal absorption of oxalates is the possible mechanism.