Assessing the safety and efficacy of the ClearRing™ implant for the treatment of benign prostatic hyperplasia in a canine model

Background: Transurethral resection of the prostate is the most common procedure for the treatment of benign prostatic hyperplasia (BPH). Although effective, transurethral resection of the prostate can be associated with side effects including prolonged recovery, storage and voiding symptoms, risk of acute urinary retention. Objectives: In this study, we describe a new minimally invasive device for the treatment of lower urinary track symptoms due to BPH, implanting a nitinol C shape ring in a circular incision in the prostatic tissue, surrounding the urethra, done by electrocuting blade over a dilatation balloon. Methods: Two groups of dogs (4/ group) were implanted with the device under anesthesia. Clinical observation, body weight and weekly blood and urinary tests were performed throughout the study period to evaluate safety. Fluoroscopy and cystoscopy were used throughout the study period to evaluate implant condition and urethral dilatation. At the end of 3 weeks (Group I) or 3 months (Group II), the animals were sacrificed. The implantation site was examined macroscopically and histologically to evaluate urethral dilatation and tissue response. Results: The presence of the ClearRing™ implant in an animal's prostate was associated with significant dilatation of the prostatic urethra. Fever, pain, behavior disturbances or gross hematuria, when occurred, resolved within 72 hours post procedure and no severe adverse events were observed. There was no evidence of prostatic hyperplasia associated to ring implantation. Partial epithelial coverage of the implant surface was observed without evidence of encrustation. Conclusion: The ClearRing™ implant seems a feasible minimally invasive procedure for relieving lower urinary track symptoms due to BPH.