Urinary bladder calculus formation on sutures in rabbits, cats and dogs.

Cystotomies were performed upon 152 animals with various suture materials. The bladders were examined for the presence of concretions at intervals ranging from three to 120 days. Calculi were found with regularity in rabbits but not in cats or dogs, irrespective of the suture material used. Urinary calculi persisting later than seven days postoperatively were seen only in those rabbit bladders repaired with nonabsorbable sutures. Despite major differences in the geometry and chemical composition of the suture, the two absorbable sutures polyglycolic acid and catgut showed an equivalent incidence of early, reversible calculus formation in the rabbit urinary bladder. The property of suture materials that contributes most to the formation of persistent urinary calculi is nonabsorbability. Surface characteristics and cross sectional geometry appear to play little, or no, role in the calculus formation in the bladders of animals.