A NOVEL CANINE MODEL OF PARTIAL OUTLET OBSTRUCTION SECONDARY TO PROSTATIC HYPERTROPHY

Benign prostatic hyperplasia (BPH) is a major medical problem in the U nited States. The primary medical complication of BPH is progressive o bstruction of the urethra and a subsequent in reduction the ability or the bladder to empty efficiently. The urodynamic characteristics asso ciated with BPH include hyperreflexia, increased bladder capacity, inc reased frequency, decreased flow rate, and increased residual volume. Although there currently are individual animal models of prostate enla rgement and animal models of partial outlet obstruction, there is no m odel of progressive obstruction secondary to prostate enlargement. The primary objective of the current study was to develop a canine model of BPH that would secondarily result in partial urethral obstruction a nd impaired urodynamics. Our model consists of encapsulating the prost ate in a nylon mesh to prevent the growth of the prostate into the per itoneal cavity and then treating the dog with steroids to induce prost ate growth and subsequently produce urethral constriction. The results demonstrate that encapsulation of the dog prostate and administration of steroids results in an increase in prostate mass simultaneously wi th an increase in urethral pressure and in changes in bladder contract ion consistent with the presence of partial outlet obstruction. This p reliminary study demonstrates that by preventing the outward growth of the steroid-stimulated prostate, urethral obstruction resembling BPH can be produced.