The prostatic urethral lift (PUL) using UroLift® implants has been shown to provide rapid, significant, durable improvement of symptoms from benign prostatic hyperplasia (BPH). Since little has been published about the short-term and long-term mechanism of action of the implants, animal and clinical studies and post-market data were analyzed to elucidate these points.

4 PUL patients underwent cystoscopy at 6-27 months post-procedure. Prostatic tissue was then resected from these patients at 13-43 months for symptom return, and  histopathology was performed on the tissue surrounding the excised implants. In animal studies, 24 dogs underwent PUL and histopathology was used to examine the tissue surrounding the implants excised at 1, 3, 6 and 12 months. Worldwide post-market data from April 2018 to September 2019 were reviewed for implant migration, encrustation, and breakage

Clinical cystoscopy shows a widened urethra and retracted lobes when the implant capsular tab (CT) is anchored on the capsule and the urethral endpiece (UE) compresses the urothelium. Canine histopathology shows that this localized tissue compression decreases blood flow, inciting benign lobular atrophy (Figure 1) that continues until compression is relieved. Human data showed similar results. Healing begins immediately post-implantation with 1) tissue compression that results in decreased blood flow, followed by 2) minimal-mild chronic inflammation at 1 month which decreased to minimal chronic inflammation by 12 months, 3) moderate lobular atrophy beginning at 1 month post-implantation and increasing at 12 months, and 4) minimal-mild fibrosis first seen at 6 months post-implantation which is stable through 12 months. Canine and human tissue histopathology also shows no encrustation or necrosis and a stable healing process marked by minimal-mild chronic inflammation, fibrosis, lobular atrophy, and implant epithelialization. The UE invaginates into the tissue and typically becomes epithelialized. Post-market data from over 400,000 implants demonstrate no cases of migration after a successful deployment, a 0.005% rate of stone formation from encrustation and a 0.004% breakage rate.

The PUL implants utilize a mechanical mode of action by attaching onto the fibromuscular capsule and peri-urethral tissue, thus widening the urethra. Human and animal histopathology data and post-market analysis indicate that the implants are benign and safe with no cases of implant migration, and minimal risk for stone formation or breakage. The healing process is stable and begins with minimal-mild chronic inflammation which decreases by 12 months; tissue remodeling occurs beginning with moderate lobular atrophy at 1 month and continues until the tissue acclimates to compression.

Results from human and animal tissue analysis and post-market worldwide data indicates the benign, non-irritative nature of this non-thermal approach. The implants cause localized compression that induces remodeling,  scarring and fibrosis, and when placed properly, safely affects these changes with minimal risk of migration, encrustation, or breakage.