madman
Super Moderator
Abstract
Purpose
To conduct a scoping review of the existing literature and recent developments on prostatic stents for the treatment of benign prostatic hyperplasia (BPH).
Methods
A comprehensive search was performed on Embase, MEDLINE, and Web of Science to identify English literature on prostatic stents for the treatment of BPH. Additional studies and upcoming devices were identified through grey literature search and expert consultation. Study characteristics and stent information were extracted and tabulated narratively.
Results
Of the 1171 search results, 64 studies were included in this review. iTiND was the prostatic stent with the most long-term evidence. iTiND is a safe and effective minimally invasive treatment for BPH that preserves sexual function. Adverse events are mild and transitory. Emerging stents (e.g. Zenfow, Butterfy, Urocross, and Exime) had 7/64 eligible studies, where no studies had long-term follow-up. These newer stents show promising results for quality of life and BPH symptom management; however, long-term monitoring and head-to-head comparisons are needed.
Conclusion
Over the last 50 years, prostatic stents have evolved and demonstrated improved clinical efficacy. iTiND provides a safe and effective outpatient treatment of LUTS secondary to BPH preserving erectile and ejaculatory function. Emerging prostatic stents are a promising, effective, and safe intervention in well-selected patients interested in its benefits.
Past Stents
UroLume
The UroLume (American Medical Systems, Minnetonka, Minnesota) stent was one of the first permanent stents developed with the literature dating back to 1991, marking the beginning of stent technology as an intervention for BPH. Made of alloy material which can be integrated into the urethra, this stent is a self-expanding mesh cylinder which is endoscopically implanted with local, regional, or general anesthetic, improving the prevalence of LUTS [8]
Memokath/Memocath
Through a thermo-sensitive mechanism and nitinol, the Memokath® (Doctors and Engineers, Kvistjaard, Denmark) stent softens before insertion and, once endoscopically implanted, returns to a cone shape which pushes the stent into the urethra in order to keep it open and unobstructed [11].
Poly‑l‑lactic and poly‑l‑glycolic copolymer spiral stents
Poly-l-lactic and poly-l-glycolic (PLGA) copolymer spiral stent is a self-expandable and self-reinforced device with a lactic/glycolic molar ratio 80/20, typically degrading in 2–2.5 months. It was designed to prevent postoperative urinary retention in patients with prostatic edema and bladder outlet obstruction following interstitial laser coagulation of the prostate (ILCP).
Braided poly(lactic‑co‑glycolic acid) urethral stent
Present stents
Allium TPS
The Allium™ TPS (Allium TPS, Allium Medical, Caesarea) is a nitinol-built polymer-covered stent, preventing tissue growth and avoiding encrustations. The insertion procedure is performed endoscopically with local anesthetic, and studies have recommended it as an effective alternative to indwelling catheterization [17]. The soft proximal segment prevents sphincter dysfunction that may cause incontinence [18]. With various available lengths ranging from 30 to 65 mm with a large calibre, the chances of stent migration are reduced.
iTiND the temporary implantable nitinol device
iTiND (Medi-Tate, Hadera, Israel/Olympus Corporation, Tokyo, Japan) is a second-generation FDA-approved nitinol device [20]. It consists of three nitinol struts, an anti-migration anchoring leaflet and a polyester retrieval suture [6]. The device is inserted through a flexible cystoscope under sedation or local anesthesia in an outpatient setting.
The Spanner™
The Spanner (The Spanner, AbbeyMoor Medical, Inc., Minnesota, USA) is an FDA-approved temporary silicone elastomer prostatic stent [30]. It is placed under topical anesthesia in an outpatient setting without cystoscope visualization. Candidates must possess an intact reflex detrusor contraction and pelvic floor relaxation for optimal results from this stent.
Future stents
Zenfow™
Currently undergoing clinical trials, the ZenFlow™ Spring (Zenfow, South San Francisco, CA, USA) is a small nitinol-based implant inserted with local anesthetic through a flexible cystoscope to treat BPH symptoms [34]. Designed to be permanent but can be removed, the spring creates internal tension which helps the device incorporate into the wall of the urethra.
Prodeon Urocross™
The Urocross™ Expander System (Prodeon Medical, Inc. (PMI), Sunnyvale, California, USA; formally branded as the XFLO Expander System) has been developed for use with a flexible cystoscope. It is comprised of a stent and delivery system designed for implantation in the prostatic urethra and its retrieval after implantation for a minimum of one month and up to 12 months. Local or general anesthetic is used, depending on whether the procedure is completed in a cystoscopy suite or operating room [36]. The temporary implant is a nitinol device developed to expand and reshape the prostatic urethra, through gentle mechanical tissue retraction to
alleviate urinary outflow obstruction which leads to LUTS.
Proverum ProVee
The ProVee device is a ‘stent-like’ nitinol expander designed to gently reshape and open the obstructed urethra without heating, piercing, cutting, or removing part of the prostate. The delivery system for the expander is thinner than most treatment options, and the uncomplicated procedure is intended to be performed in an outpatient or doctor’s office setting with local anesthetic [37]
Butterfy™
The Butterfy™ (Butterfy, Medical Ltd, Yokneam, Yilit, Israel) device is another new metallic implant that retracts the lateral lobes of the prostate and is easily delivered with either a rigid or fexible cystoscope under local anesthesia in an outpatient setting [39]. It is designed to be permanent but can easily be extracted [40]. It avoids invasive techniques such as cutting, ablation, heating, or removing prostatic tissue, as well as the need for catheterization afterwards [5].
EXIME®
The Exime® catheter (Rocamed; Munich, Germany) is a single-use temporary (up to 30 days) prostatic stent inserted in the prostatic urethra before the sphincter, acting as a substitute for a Foley catheter [42]. It was designed to allow voluntary urination in males with acute or chronic urinary retention due to BPH. Exime is inserted in an office-based setting under local anesthetic without cystoscopy, sonography, or fluoroscopy guidance.
Conclusion
The revolution of prostatic stent technology for BPH has been gradually evolving for several years. Early designs of these devices have been shown to result in adverse outcomes such as migration, encrustation, and complications that have resulted in stent failure. Through this overview, it is evident that the shift towards TMIST and prostatic stents serves as an effective bridge between medical and surgical therapies for BPH. Prostatic stents continue to show increasing promise as a safe, effective, and durable intervention for BPH to better QoL and decrease rates of IPSS and LUTS/BOO. As current trials are on the trajectory to investigate the positive long-term implications of prostatic stents, further data are required to support the notion that the development of stent technology is advantageous for this population.
Purpose
To conduct a scoping review of the existing literature and recent developments on prostatic stents for the treatment of benign prostatic hyperplasia (BPH).
Methods
A comprehensive search was performed on Embase, MEDLINE, and Web of Science to identify English literature on prostatic stents for the treatment of BPH. Additional studies and upcoming devices were identified through grey literature search and expert consultation. Study characteristics and stent information were extracted and tabulated narratively.
Results
Of the 1171 search results, 64 studies were included in this review. iTiND was the prostatic stent with the most long-term evidence. iTiND is a safe and effective minimally invasive treatment for BPH that preserves sexual function. Adverse events are mild and transitory. Emerging stents (e.g. Zenfow, Butterfy, Urocross, and Exime) had 7/64 eligible studies, where no studies had long-term follow-up. These newer stents show promising results for quality of life and BPH symptom management; however, long-term monitoring and head-to-head comparisons are needed.
Conclusion
Over the last 50 years, prostatic stents have evolved and demonstrated improved clinical efficacy. iTiND provides a safe and effective outpatient treatment of LUTS secondary to BPH preserving erectile and ejaculatory function. Emerging prostatic stents are a promising, effective, and safe intervention in well-selected patients interested in its benefits.
Past Stents
UroLume
The UroLume (American Medical Systems, Minnetonka, Minnesota) stent was one of the first permanent stents developed with the literature dating back to 1991, marking the beginning of stent technology as an intervention for BPH. Made of alloy material which can be integrated into the urethra, this stent is a self-expanding mesh cylinder which is endoscopically implanted with local, regional, or general anesthetic, improving the prevalence of LUTS [8]
Memokath/Memocath
Through a thermo-sensitive mechanism and nitinol, the Memokath® (Doctors and Engineers, Kvistjaard, Denmark) stent softens before insertion and, once endoscopically implanted, returns to a cone shape which pushes the stent into the urethra in order to keep it open and unobstructed [11].
Poly‑l‑lactic and poly‑l‑glycolic copolymer spiral stents
Poly-l-lactic and poly-l-glycolic (PLGA) copolymer spiral stent is a self-expandable and self-reinforced device with a lactic/glycolic molar ratio 80/20, typically degrading in 2–2.5 months. It was designed to prevent postoperative urinary retention in patients with prostatic edema and bladder outlet obstruction following interstitial laser coagulation of the prostate (ILCP).
Braided poly(lactic‑co‑glycolic acid) urethral stent
Present stents
Allium TPS
The Allium™ TPS (Allium TPS, Allium Medical, Caesarea) is a nitinol-built polymer-covered stent, preventing tissue growth and avoiding encrustations. The insertion procedure is performed endoscopically with local anesthetic, and studies have recommended it as an effective alternative to indwelling catheterization [17]. The soft proximal segment prevents sphincter dysfunction that may cause incontinence [18]. With various available lengths ranging from 30 to 65 mm with a large calibre, the chances of stent migration are reduced.
iTiND the temporary implantable nitinol device
iTiND (Medi-Tate, Hadera, Israel/Olympus Corporation, Tokyo, Japan) is a second-generation FDA-approved nitinol device [20]. It consists of three nitinol struts, an anti-migration anchoring leaflet and a polyester retrieval suture [6]. The device is inserted through a flexible cystoscope under sedation or local anesthesia in an outpatient setting.
The Spanner™
The Spanner (The Spanner, AbbeyMoor Medical, Inc., Minnesota, USA) is an FDA-approved temporary silicone elastomer prostatic stent [30]. It is placed under topical anesthesia in an outpatient setting without cystoscope visualization. Candidates must possess an intact reflex detrusor contraction and pelvic floor relaxation for optimal results from this stent.
Future stents
Zenfow™
Currently undergoing clinical trials, the ZenFlow™ Spring (Zenfow, South San Francisco, CA, USA) is a small nitinol-based implant inserted with local anesthetic through a flexible cystoscope to treat BPH symptoms [34]. Designed to be permanent but can be removed, the spring creates internal tension which helps the device incorporate into the wall of the urethra.
Prodeon Urocross™
The Urocross™ Expander System (Prodeon Medical, Inc. (PMI), Sunnyvale, California, USA; formally branded as the XFLO Expander System) has been developed for use with a flexible cystoscope. It is comprised of a stent and delivery system designed for implantation in the prostatic urethra and its retrieval after implantation for a minimum of one month and up to 12 months. Local or general anesthetic is used, depending on whether the procedure is completed in a cystoscopy suite or operating room [36]. The temporary implant is a nitinol device developed to expand and reshape the prostatic urethra, through gentle mechanical tissue retraction to
alleviate urinary outflow obstruction which leads to LUTS.
Proverum ProVee
The ProVee device is a ‘stent-like’ nitinol expander designed to gently reshape and open the obstructed urethra without heating, piercing, cutting, or removing part of the prostate. The delivery system for the expander is thinner than most treatment options, and the uncomplicated procedure is intended to be performed in an outpatient or doctor’s office setting with local anesthetic [37]
Butterfy™
The Butterfy™ (Butterfy, Medical Ltd, Yokneam, Yilit, Israel) device is another new metallic implant that retracts the lateral lobes of the prostate and is easily delivered with either a rigid or fexible cystoscope under local anesthesia in an outpatient setting [39]. It is designed to be permanent but can easily be extracted [40]. It avoids invasive techniques such as cutting, ablation, heating, or removing prostatic tissue, as well as the need for catheterization afterwards [5].
EXIME®
The Exime® catheter (Rocamed; Munich, Germany) is a single-use temporary (up to 30 days) prostatic stent inserted in the prostatic urethra before the sphincter, acting as a substitute for a Foley catheter [42]. It was designed to allow voluntary urination in males with acute or chronic urinary retention due to BPH. Exime is inserted in an office-based setting under local anesthetic without cystoscopy, sonography, or fluoroscopy guidance.
Conclusion
The revolution of prostatic stent technology for BPH has been gradually evolving for several years. Early designs of these devices have been shown to result in adverse outcomes such as migration, encrustation, and complications that have resulted in stent failure. Through this overview, it is evident that the shift towards TMIST and prostatic stents serves as an effective bridge between medical and surgical therapies for BPH. Prostatic stents continue to show increasing promise as a safe, effective, and durable intervention for BPH to better QoL and decrease rates of IPSS and LUTS/BOO. As current trials are on the trajectory to investigate the positive long-term implications of prostatic stents, further data are required to support the notion that the development of stent technology is advantageous for this population.
