Temporary placement of a covered, retrievable, barbed stent for the treatment of hormone-induced benign prostatic hyperplasia: Technical feasibility and histologic changes in canine prostates

Purpose: To evaluate the technical feasibility of a covered, retrievable, barbed prostatic stent and to determine stent-induced histologic changes of the prostate in canine benign prostatic hyperplasia (BPH). Materials and Methods: BPH was induced in 8 male beagles by administration of dihydrotestosterone and β-estradiol. Under fluoroscopy guidance, covered, retrievable, barbed stents were placed in the prostatic urethras. Urethrograms were obtained every three to 4 weeks until sacrifice. The stents were removed 8 weeks after placement. The dogs were sacrificed immediately (group A, n = 4) and 8 weeks after stent removal (group B, n = 4). Histologic changes of prostates were microscopically evaluated. Results: Stent placement was technically successful in all dogs. The diameters of the prostatic urethra were 14.1 mm ± 0.5 and 13.7 mm ± 0.5 on urethrograms obtained immediately after and 8 weeks after stent removal (P = .268). Stent removal was successful in all dogs except one, in which the stent was obstructed by stone formation. Small sandy stones were identified attached to the removed stents of two dogs. Histologic examination revealed extensive prostatic glandular atrophy involving 95.1% ± 2.2 (group A) and 94.5% ± 2.4 (group B) of entire prostate (P = .773). Conclusions: A covered, retrievable, barbed prostatic stent seems to be feasible for use in hormone-induced canine BPH. The stent induced prostatic urethral dilatation, and extensive prostatic glandular atrophy persisted up to 8 weeks after stent removal.