madman
Super Moderator
New Technologies for Treatment of Benign Prostatic Hyperplasia (2021)
Dean Elterman, MD, MS, FRCSC, Bruce Gao, MD, Steven Lub, Naeem Bhojani, MD, FRCSC, Kevin C. Zorn, MD, FRCSC, Bilal Chughtai, MD
INTRODUCTION
Benign prostatic hyperplasia (BPH) is a ubiquitous disease that affects 50% of men at age 60 years and 90% of men aged older than 80 years.1,2 Bothersome lower urinary tract symptoms (LUTSs) secondary to BPH are responsible for a significant health care system burden, incurring approximately 4 billion dollars annually in the United States.3 Furthermore, LUTSs contribute to a significant reduction in patient quality of life (QoL) with more than 35 million men aged older than 30 years having at least mild LUTSs.4 In an aging society with rising rates of BPH, there is a significant need for safe, effective, reliable, and universally available (both to the patient and urology community with access and a short learning curve) therapeutic options.
BPH is a urologic disease managed by a stepwise approach involving lifestyle alteration, medical therapy, and surgery. Through shared-decision making and ideally the use of a BPH decision aid, an individualized treatment plan takes into account factors including prostate anatomy, treatment efficacy, the severity of symptoms, safety, side effects, and costs.5 Medical therapy in the form of alpha-blockers or 5-alpha-reductase inhibitors, although effective, may be complicated by unwanted sexual side effects such as erectile dysfunction (ED), decreased libido, and ejaculatory problems, along with the burden of taking lifelong medications.6 Recent studies have also shown that some of these medications can have significant neurocognitive and psychiatric effects, including dementia and depression.7
Indications for surgery may include LUTSs refractory to medical therapy, patient preference, or certain medical situations such as recurrent Urinary tract infections, bladder stones, gross hematuria, renal insufficiency, or urinary retention. In these cases, transurethral resection of the prostate (TURP) remains the gold standard. Although efficacious, TURP requires the use of general or spinal anesthesia as well as runs the risk of bleeding, urinary incontinence, retrograde ejaculation, and ED.8 Sexual health surveys indicate that maintenance of sexual function is significantly prioritized by patients who underwent BPH surgery, with postoperative erections and ejaculatory function important to 95% and 92% of men, respectively, regardless of age.9
To address these treatment shortcomings, innovative new technologies for the treatment of BPH have been developed. These technologies target rapid recovery and symptom relief, low complication rates, sexual preservation, and the ability to perform the procedure in an outpatient setting with local anesthesia.
In this review, we provide an update on the techniques and outcomes of seven novel technologies for BPH including Aquablation, Rezum, UroLift, iTind, Zenflow, Optilume, and XFLO.
AQUABLATION
Technique
The AquaBeam Robotic System (PROCEPT BioRobotics, Redwood City, Ca, USA) is an ultrasound-guided surgical technique that uses a heat-free, high-velocity waterjet (Aquablation) to endoscopically resect obstructing prostatic tissue.10,11 The AquaBeam system consists of three main components: the robotic handpiece, the surgeon console, and the conformal planning unit (CPU).10 The patient is prepped and positioned in the dorsal lithotomy position under general or spinal anesthesia. A bi-plane transrectal ultrasound transducer (TRUS) is inserted and positioned to visualize the prostate in real-time. The 24-Fr robotic handpiece with an integrated flexible scope is inserted into the bladder, and the scope is retracted back to visualize the bladder neck. Once the TRUS and the handpiece are successfully positioned and locked in place to robotic arms, the surgeon defines the length, depth, and angle of resection in the CPU using the transverse and sagittal ultrasound views of the prostate.10 The maximum angle of resection is 225, and the maximum cut depth is 25 mm, allowing the surgeon to tailor the procedure to the specific prostate.10 In a “windshield wiper” motion, high-velocity saline follows the outlined plan and resects the obstructing prostatic tissue while sparing the bladder neck and verumontanum. Reported average resection times are around 5 minutes.12 Lastly, hemostasis may be achieved through focal bladder neck cautery (FBNC) via a standard resectoscope, and a three-way catheter is inserted afterward for bladder irrigation.13 (Fig. 1).
Efficacy and safety
Like other surgical BPH technologies, Aquablation is associated with the risk of blood loss and possible transfusion. It is not an approved treatment of BPH for men on anticoagulation. One key difference between TURP and Aquablation is that the latter lacks a direct method of achieving postresection hemostasis.10
WATER VAPOR THERMAL THERAPY (REZUM)
Technique
Rezum (Boston Scientific Corp, Marlborough, MA, USA) water vapor therapy is a type of thermal ablative technique that achieves heat transfer via convection.21–23 (Fig. 2). The key components of the system include a radiofrequency (RF) generator, a single-use transurethral delivery device with an integrated 30 cystoscopic lens for direct visualization, a retractable 18-gauge polyetheretherketone (PEEK) needle, and a saline flush.21 Once the patient is prepped and positioned in a dorsal lithotomy position, coupled with patient anesthesia (local block or sedation), the surgeon guides the delivery device into the prostatic urethra under direct cystoscopic visualization. The RF generator converts sterile water into steam that is then delivered and injected into prostatic adenomatous tissue by the delivery device and PEEK needle, respectively.21 The needle is designed to circumferentially disperse steam through its 3 rows of 4 holes spaced at 120 intervals.22 When the steam travels through the prostatic adenoma, it immediately phases shifts from vapor back to liquid, releasing and transferring 208 cal of thermal energy to the target tissue.22 This release of stored thermal energy causes irreversible cell membrane damage and cell death. Furthermore, because the vapor is physically less dense than the zonal boundaries of the prostate, the necrosis is contained within the zone of prostatic adenomatous tissue.22 Postprocedural MRI imaging at 6 months showed a mean reduction of total prostate volume of 15%; however, the patient sample size was small.21 Each injection travels a fixed depth of w10 mm and takes 9 seconds on average.23 The number of injections a patient requires depends on the length of the prostatic urethra, the amount of prostatic tissue, and the presence of a median lobe.23 The saline flush is responsible for both visualization and cooling of the prostatic urethra between injections. The procedure can be completed quickly in an office-based setting and is typically done using oral sedation (w70%).23 Compared with other thermal ablative techniques that use conduction (Transurethral needle ablation and Transurethral microwave therapy), Rezum causes tissue necrosis at a lower temperature in a shorter amount of time.23
Efficacy and safety
Current evidence suggests that water vapor therapy does not have a significant negative impact on sexual function.2
Rezum appears to be safe with most reported complications minor in nature (Clavien I-II). In Rezum II, the most common issues were dysuria (16.9%), hematuria (11.8%), frequency or urgency (5.9%), acute urinary retention (3.7%), and suspected UTI (3.7%).25 All of these complications were resolved within 30 days.
UroLift (PROSTATIC URETHRAL LIFT)
Technique
UroLift (NeoTract/Teleflex Inc, Pleasanton, CA, USA) or prostatic urethral lift (PUL) uses permanent implants which are cystoscopically deployed through obstructing prostatic tissue.33 (Fig. 3). This mechanical solution is similar in theory to window curtain tie backs that retract the obstructed prostatic urethra to the prostatic capsule. The UroLift System consists of two main components: a transurethral delivery device with an integrated cystoscope and permanent nitinol and stainless steel implants.33 Once the surgeon positions the transurethral delivery device at the desired location, the implants are inserted and subsequently compress and retract the prostatic adenomatous tissue. Similar to Rezum, the number of implants a patient requires depends on the length of the prostatic urethra the amount of prostatic tissue and the presence of a median lobe. The procedure typically takes less than 1 hour and can be done in the office using local anesthesia.34
Efficacy and safety
The American Urological Association guidelines currently exclude men with an obstructive median lobe for UroLift due to MedLift being a randomized cohort study rather than an RCT.
The surgical reintervention rate for UroLift is still being determined but has been estimated at 2% to 3% per year.
A majority (>95%) of complications in UroLift are minor in nature (Clavien grade 1).39 In a recent retrospective observational cohort study out of England, the most common adverse events were urinary retention (1.4%), followed by bleeding (0.9%).40 Sexual function appears to be preserved in PUL. The LIFT and crossover study both reported 0% de novo sustained ejaculatory or ED.36
True Minimally Invasive Surgical Therapies
True minimally invasive surgical therapy (TMIST) is a novel concept within minimally invasive surgical therapies for BPH that bridges medical therapy and more aggressive surgical therapy. TMIST is an off-the-shelf BPH therapy requiring only a standard flexible cystoscope that can be performed in a urology office without sedation or general anesthesia.41 This paradigm shift in BPH management allows flexible cystoscopy to become both diagnostic and therapeutic. Durability is not necessarily the primary target for TMISTs but rather an effective and cost-effective bridge between conservative medical therapy and more invasive surgical therapy that may decrease health care system costs, operating room burden, and need for added equipment.41
The following novel technologies below are considered by these authors to be TMISTs. iTind is currently the only TMIST with FDA approval. The Optilume BPH Catheter System, Prodeon XFLO Expander System, Zenflow Spring System, and Butterfly Prostatic Retraction device are currently in phase 3 clinical trials.
iTind (TEMPORARILY IMPLANTED NITINOL DEVICE)
Technique
The second-generation iTind system (Medi-Tate, Hadera, Israel) is a temporarily implanted nitinol device that is deployed in the prostatic urethra and bladder neck.42,43 (Fig. 4). The device is made up of three elongated nitinol struts connected at the distal end, an antimigration anchoring leaflet, and a polyester retrieval suture.42 In the lithotomy position, using a standard 19 to 22 Fr cystoscope, the surgeon inserts the enclosed device through the cystoscope sheath and into the bladder. The device is then deployed and retracted so that the anchoring leaflet is under the bladder neck at the 6 o’clock position and the 3 struts are in the 12, 5, and 7 o’clock positions within the prostatic urethra.42 Once inserted, the bladder is drained, and the patient is discharged with simple analgesia. The total procedure time is less than 10 minutes, and most cases are done in the office-based setting using local anesthesia. Over the next 5 to 7 days, the 3 struts apply continuous pressure on the prostatic urethra and cause ischemic incisions at the contact points.43 This process expands and reshapes the bladder neck and prostatic urethra, creating an open channel for the flow of urine. After a week, the patient has the device removed by using the retrieval suture and a special open-ended silicone catheter that allows the device to be collapsed and removed safely without a cystoscope or anesthesia.43 Catheterization is not necessary after placement and removal of the device. Patients are discharged on the same day. The first-generation iTind system differed from the second-generation iTind system by the use of 4 elongated struts and a tip that was pointed and covered in soft plastic material.43
Efficacy and safety
In line with the 3-year prospective studies, there were no reported de novo retrograde ejaculation or ED. The retreatment rate within 1 year was 4.7%.
Current studies on iTind have reported perioperative minor self-limiting complications (Clavien grade 1 and 2). Common complications included transient hematuria, urgency, and dysuria (Table 1).
OPTILUME BPH CATHETER SYSTEM
Technique
The Optilume BPH Catheter System (Urotronic Inc, Plymouth, Minnesota, USA) is a mechanical solution (balloon dilation) that also delivers a localized antiproliferative drug to achieve immediate and long-term urethral patency.48 (Fig. 5). Previous clinical studies in the 1990s demonstrated that transurethral balloon dilation techniques were safe but lacked long-term durability.48 The novelty of the Optilume system revolves around the use of two balloon catheters: a predilation balloon and a drug-coated balloon. The drug-coated balloon delivers paclitaxel, a chemotherapy drug that is widely used in coronary and peripheral stents to prevent restenosis. Under the visualization of a standard flexible cystoscope, the predilation balloon catheter is advanced until the proximal end is at the level of the external sphincter. The balloon is inflated for a short amount of time and removed. Next, the drug-coated balloon repeats the same steps, further dilating the prostatic urethra as well as delivering paclitaxel to the prostatic urethral surface. The second inflation lasts for a minimum of 5 minutes before the balloon is removed.48 The balloons are locked in place by a proprietary balloon design. In both balloon dilations, the intent is to only apply dilating force to the prostatic adenomatous tissue while sparing the bladder neck. Moreover, the balloon size, diameter, and length used are specific to the prostate size and length. Initial clinical trials are performed under general anesthesia or spinal block; however, the hope is that Optilume can be deployed in an office-based setting. A Foley catheter is placed post procedurally.
Efficacy and safety
There were no reported de novo ejaculatory or ED. Furthermore, adverse events were minor self-limiting and comparable with established MISTs such as UroLift. A 500-participant prospective, double-blinded, randomized controlled trial is currently being conducted to more thoroughly evaluate the safety and efficacy of Optilume.
XFLO EXPANDER SYSTEM
Technique
The XFLO Expander System (Medeon Biodesign, Inc, Taiwan) is another mechanical solution for BPH. Based on currently available information, the XFLO system consists of a reversible nitinol tissue expander that is delivered to the prostatic urethra using a standard flexible cystoscope.49 The device is left inside the prostatic urethra but is designed to be removable using a standard flexible cystoscope and the XPRO Retrieval Sheath in an office setting. Exact device specifications, technique details, and implant durations are still in development and not fully available to the public.
Efficacy and safety
Preliminary reports suggest safety with the preservation of sexual function. Long-term follow-up data are currently being obtained and will provide additional efficacy and safety outcome measures.
ZENFLOW SPRING SYSTEM
Technique
The Zenflow Spring System (Zenflow, South San Francisco, CA, USA) uses a nitinol implant that is delivered through a proprietary flexible cystoscope to the prostatic urethra.16 Unlike the XFLO system, the spring is designed to be a permanent device that is embedded into the wall of the prostatic urethra through internal tension. Exact device specifications, technique details, and implant durations are still in development and not fully available to the public.
Efficacy and safety
Currently, interim results are available from a small first-in-man study with 24 months of follow-up. Although exact numbers are still being determined, it appears that significant IPSS improvements were seen at 12 months. Adverse events appeared to be few and minor in nature. Further results are currently being gathered in a larger, prospective, single-arm study in Canada.16
BUTTERFLY PROSTATIC RETRACTION DEVICE
Technique
The Butterfly Prostatic Retraction device (Butterfly, Medical Ltd, Yokneam, Yilit, Israel) is a nitinol implant shaped like a butterfly designed to reside in the prostatic urethra and unobstruct lateral prostate lobes. The single-use device is folded into a thin and flexible unit and can be placed with a flexible cystoscope. The Butterfly is designed to be a permanent solution but can also be removed easily under local anesthesia.1
Efficacy and safety
A multicentre trial to assess safety and efficacy is currently in progress.16
SUMMARY
BPH is a common, progressive disease affecting aging men which have a significant impact on patient QoL. In an effort to address the rising demand for BPH therapy that is both effective and safe, innovative technologies promise rapid recovery and symptom relief, low complication rates (especially lower rates of sexual dysfunction), and, ideally, the ability to perform the procedure in an outpatient setting with local anesthesia. Such technologies will also help expand global patient access and democratize urologic BPH care. Current results, especially for TMISTs, will require long-term data to properly assess the safety and durability of outcomes.
Dean Elterman, MD, MS, FRCSC, Bruce Gao, MD, Steven Lub, Naeem Bhojani, MD, FRCSC, Kevin C. Zorn, MD, FRCSC, Bilal Chughtai, MD
INTRODUCTION
Benign prostatic hyperplasia (BPH) is a ubiquitous disease that affects 50% of men at age 60 years and 90% of men aged older than 80 years.1,2 Bothersome lower urinary tract symptoms (LUTSs) secondary to BPH are responsible for a significant health care system burden, incurring approximately 4 billion dollars annually in the United States.3 Furthermore, LUTSs contribute to a significant reduction in patient quality of life (QoL) with more than 35 million men aged older than 30 years having at least mild LUTSs.4 In an aging society with rising rates of BPH, there is a significant need for safe, effective, reliable, and universally available (both to the patient and urology community with access and a short learning curve) therapeutic options.
BPH is a urologic disease managed by a stepwise approach involving lifestyle alteration, medical therapy, and surgery. Through shared-decision making and ideally the use of a BPH decision aid, an individualized treatment plan takes into account factors including prostate anatomy, treatment efficacy, the severity of symptoms, safety, side effects, and costs.5 Medical therapy in the form of alpha-blockers or 5-alpha-reductase inhibitors, although effective, may be complicated by unwanted sexual side effects such as erectile dysfunction (ED), decreased libido, and ejaculatory problems, along with the burden of taking lifelong medications.6 Recent studies have also shown that some of these medications can have significant neurocognitive and psychiatric effects, including dementia and depression.7
Indications for surgery may include LUTSs refractory to medical therapy, patient preference, or certain medical situations such as recurrent Urinary tract infections, bladder stones, gross hematuria, renal insufficiency, or urinary retention. In these cases, transurethral resection of the prostate (TURP) remains the gold standard. Although efficacious, TURP requires the use of general or spinal anesthesia as well as runs the risk of bleeding, urinary incontinence, retrograde ejaculation, and ED.8 Sexual health surveys indicate that maintenance of sexual function is significantly prioritized by patients who underwent BPH surgery, with postoperative erections and ejaculatory function important to 95% and 92% of men, respectively, regardless of age.9
To address these treatment shortcomings, innovative new technologies for the treatment of BPH have been developed. These technologies target rapid recovery and symptom relief, low complication rates, sexual preservation, and the ability to perform the procedure in an outpatient setting with local anesthesia.
In this review, we provide an update on the techniques and outcomes of seven novel technologies for BPH including Aquablation, Rezum, UroLift, iTind, Zenflow, Optilume, and XFLO.
AQUABLATION
Technique
The AquaBeam Robotic System (PROCEPT BioRobotics, Redwood City, Ca, USA) is an ultrasound-guided surgical technique that uses a heat-free, high-velocity waterjet (Aquablation) to endoscopically resect obstructing prostatic tissue.10,11 The AquaBeam system consists of three main components: the robotic handpiece, the surgeon console, and the conformal planning unit (CPU).10 The patient is prepped and positioned in the dorsal lithotomy position under general or spinal anesthesia. A bi-plane transrectal ultrasound transducer (TRUS) is inserted and positioned to visualize the prostate in real-time. The 24-Fr robotic handpiece with an integrated flexible scope is inserted into the bladder, and the scope is retracted back to visualize the bladder neck. Once the TRUS and the handpiece are successfully positioned and locked in place to robotic arms, the surgeon defines the length, depth, and angle of resection in the CPU using the transverse and sagittal ultrasound views of the prostate.10 The maximum angle of resection is 225, and the maximum cut depth is 25 mm, allowing the surgeon to tailor the procedure to the specific prostate.10 In a “windshield wiper” motion, high-velocity saline follows the outlined plan and resects the obstructing prostatic tissue while sparing the bladder neck and verumontanum. Reported average resection times are around 5 minutes.12 Lastly, hemostasis may be achieved through focal bladder neck cautery (FBNC) via a standard resectoscope, and a three-way catheter is inserted afterward for bladder irrigation.13 (Fig. 1).
Efficacy and safety
Like other surgical BPH technologies, Aquablation is associated with the risk of blood loss and possible transfusion. It is not an approved treatment of BPH for men on anticoagulation. One key difference between TURP and Aquablation is that the latter lacks a direct method of achieving postresection hemostasis.10
WATER VAPOR THERMAL THERAPY (REZUM)
Technique
Rezum (Boston Scientific Corp, Marlborough, MA, USA) water vapor therapy is a type of thermal ablative technique that achieves heat transfer via convection.21–23 (Fig. 2). The key components of the system include a radiofrequency (RF) generator, a single-use transurethral delivery device with an integrated 30 cystoscopic lens for direct visualization, a retractable 18-gauge polyetheretherketone (PEEK) needle, and a saline flush.21 Once the patient is prepped and positioned in a dorsal lithotomy position, coupled with patient anesthesia (local block or sedation), the surgeon guides the delivery device into the prostatic urethra under direct cystoscopic visualization. The RF generator converts sterile water into steam that is then delivered and injected into prostatic adenomatous tissue by the delivery device and PEEK needle, respectively.21 The needle is designed to circumferentially disperse steam through its 3 rows of 4 holes spaced at 120 intervals.22 When the steam travels through the prostatic adenoma, it immediately phases shifts from vapor back to liquid, releasing and transferring 208 cal of thermal energy to the target tissue.22 This release of stored thermal energy causes irreversible cell membrane damage and cell death. Furthermore, because the vapor is physically less dense than the zonal boundaries of the prostate, the necrosis is contained within the zone of prostatic adenomatous tissue.22 Postprocedural MRI imaging at 6 months showed a mean reduction of total prostate volume of 15%; however, the patient sample size was small.21 Each injection travels a fixed depth of w10 mm and takes 9 seconds on average.23 The number of injections a patient requires depends on the length of the prostatic urethra, the amount of prostatic tissue, and the presence of a median lobe.23 The saline flush is responsible for both visualization and cooling of the prostatic urethra between injections. The procedure can be completed quickly in an office-based setting and is typically done using oral sedation (w70%).23 Compared with other thermal ablative techniques that use conduction (Transurethral needle ablation and Transurethral microwave therapy), Rezum causes tissue necrosis at a lower temperature in a shorter amount of time.23
Efficacy and safety
Current evidence suggests that water vapor therapy does not have a significant negative impact on sexual function.2
Rezum appears to be safe with most reported complications minor in nature (Clavien I-II). In Rezum II, the most common issues were dysuria (16.9%), hematuria (11.8%), frequency or urgency (5.9%), acute urinary retention (3.7%), and suspected UTI (3.7%).25 All of these complications were resolved within 30 days.
UroLift (PROSTATIC URETHRAL LIFT)
Technique
UroLift (NeoTract/Teleflex Inc, Pleasanton, CA, USA) or prostatic urethral lift (PUL) uses permanent implants which are cystoscopically deployed through obstructing prostatic tissue.33 (Fig. 3). This mechanical solution is similar in theory to window curtain tie backs that retract the obstructed prostatic urethra to the prostatic capsule. The UroLift System consists of two main components: a transurethral delivery device with an integrated cystoscope and permanent nitinol and stainless steel implants.33 Once the surgeon positions the transurethral delivery device at the desired location, the implants are inserted and subsequently compress and retract the prostatic adenomatous tissue. Similar to Rezum, the number of implants a patient requires depends on the length of the prostatic urethra the amount of prostatic tissue and the presence of a median lobe. The procedure typically takes less than 1 hour and can be done in the office using local anesthesia.34
Efficacy and safety
The American Urological Association guidelines currently exclude men with an obstructive median lobe for UroLift due to MedLift being a randomized cohort study rather than an RCT.
The surgical reintervention rate for UroLift is still being determined but has been estimated at 2% to 3% per year.
A majority (>95%) of complications in UroLift are minor in nature (Clavien grade 1).39 In a recent retrospective observational cohort study out of England, the most common adverse events were urinary retention (1.4%), followed by bleeding (0.9%).40 Sexual function appears to be preserved in PUL. The LIFT and crossover study both reported 0% de novo sustained ejaculatory or ED.36
True Minimally Invasive Surgical Therapies
True minimally invasive surgical therapy (TMIST) is a novel concept within minimally invasive surgical therapies for BPH that bridges medical therapy and more aggressive surgical therapy. TMIST is an off-the-shelf BPH therapy requiring only a standard flexible cystoscope that can be performed in a urology office without sedation or general anesthesia.41 This paradigm shift in BPH management allows flexible cystoscopy to become both diagnostic and therapeutic. Durability is not necessarily the primary target for TMISTs but rather an effective and cost-effective bridge between conservative medical therapy and more invasive surgical therapy that may decrease health care system costs, operating room burden, and need for added equipment.41
The following novel technologies below are considered by these authors to be TMISTs. iTind is currently the only TMIST with FDA approval. The Optilume BPH Catheter System, Prodeon XFLO Expander System, Zenflow Spring System, and Butterfly Prostatic Retraction device are currently in phase 3 clinical trials.
iTind (TEMPORARILY IMPLANTED NITINOL DEVICE)
Technique
The second-generation iTind system (Medi-Tate, Hadera, Israel) is a temporarily implanted nitinol device that is deployed in the prostatic urethra and bladder neck.42,43 (Fig. 4). The device is made up of three elongated nitinol struts connected at the distal end, an antimigration anchoring leaflet, and a polyester retrieval suture.42 In the lithotomy position, using a standard 19 to 22 Fr cystoscope, the surgeon inserts the enclosed device through the cystoscope sheath and into the bladder. The device is then deployed and retracted so that the anchoring leaflet is under the bladder neck at the 6 o’clock position and the 3 struts are in the 12, 5, and 7 o’clock positions within the prostatic urethra.42 Once inserted, the bladder is drained, and the patient is discharged with simple analgesia. The total procedure time is less than 10 minutes, and most cases are done in the office-based setting using local anesthesia. Over the next 5 to 7 days, the 3 struts apply continuous pressure on the prostatic urethra and cause ischemic incisions at the contact points.43 This process expands and reshapes the bladder neck and prostatic urethra, creating an open channel for the flow of urine. After a week, the patient has the device removed by using the retrieval suture and a special open-ended silicone catheter that allows the device to be collapsed and removed safely without a cystoscope or anesthesia.43 Catheterization is not necessary after placement and removal of the device. Patients are discharged on the same day. The first-generation iTind system differed from the second-generation iTind system by the use of 4 elongated struts and a tip that was pointed and covered in soft plastic material.43
Efficacy and safety
In line with the 3-year prospective studies, there were no reported de novo retrograde ejaculation or ED. The retreatment rate within 1 year was 4.7%.
Current studies on iTind have reported perioperative minor self-limiting complications (Clavien grade 1 and 2). Common complications included transient hematuria, urgency, and dysuria (Table 1).
OPTILUME BPH CATHETER SYSTEM
Technique
The Optilume BPH Catheter System (Urotronic Inc, Plymouth, Minnesota, USA) is a mechanical solution (balloon dilation) that also delivers a localized antiproliferative drug to achieve immediate and long-term urethral patency.48 (Fig. 5). Previous clinical studies in the 1990s demonstrated that transurethral balloon dilation techniques were safe but lacked long-term durability.48 The novelty of the Optilume system revolves around the use of two balloon catheters: a predilation balloon and a drug-coated balloon. The drug-coated balloon delivers paclitaxel, a chemotherapy drug that is widely used in coronary and peripheral stents to prevent restenosis. Under the visualization of a standard flexible cystoscope, the predilation balloon catheter is advanced until the proximal end is at the level of the external sphincter. The balloon is inflated for a short amount of time and removed. Next, the drug-coated balloon repeats the same steps, further dilating the prostatic urethra as well as delivering paclitaxel to the prostatic urethral surface. The second inflation lasts for a minimum of 5 minutes before the balloon is removed.48 The balloons are locked in place by a proprietary balloon design. In both balloon dilations, the intent is to only apply dilating force to the prostatic adenomatous tissue while sparing the bladder neck. Moreover, the balloon size, diameter, and length used are specific to the prostate size and length. Initial clinical trials are performed under general anesthesia or spinal block; however, the hope is that Optilume can be deployed in an office-based setting. A Foley catheter is placed post procedurally.
Efficacy and safety
There were no reported de novo ejaculatory or ED. Furthermore, adverse events were minor self-limiting and comparable with established MISTs such as UroLift. A 500-participant prospective, double-blinded, randomized controlled trial is currently being conducted to more thoroughly evaluate the safety and efficacy of Optilume.
XFLO EXPANDER SYSTEM
Technique
The XFLO Expander System (Medeon Biodesign, Inc, Taiwan) is another mechanical solution for BPH. Based on currently available information, the XFLO system consists of a reversible nitinol tissue expander that is delivered to the prostatic urethra using a standard flexible cystoscope.49 The device is left inside the prostatic urethra but is designed to be removable using a standard flexible cystoscope and the XPRO Retrieval Sheath in an office setting. Exact device specifications, technique details, and implant durations are still in development and not fully available to the public.
Efficacy and safety
Preliminary reports suggest safety with the preservation of sexual function. Long-term follow-up data are currently being obtained and will provide additional efficacy and safety outcome measures.
ZENFLOW SPRING SYSTEM
Technique
The Zenflow Spring System (Zenflow, South San Francisco, CA, USA) uses a nitinol implant that is delivered through a proprietary flexible cystoscope to the prostatic urethra.16 Unlike the XFLO system, the spring is designed to be a permanent device that is embedded into the wall of the prostatic urethra through internal tension. Exact device specifications, technique details, and implant durations are still in development and not fully available to the public.
Efficacy and safety
Currently, interim results are available from a small first-in-man study with 24 months of follow-up. Although exact numbers are still being determined, it appears that significant IPSS improvements were seen at 12 months. Adverse events appeared to be few and minor in nature. Further results are currently being gathered in a larger, prospective, single-arm study in Canada.16
BUTTERFLY PROSTATIC RETRACTION DEVICE
Technique
The Butterfly Prostatic Retraction device (Butterfly, Medical Ltd, Yokneam, Yilit, Israel) is a nitinol implant shaped like a butterfly designed to reside in the prostatic urethra and unobstruct lateral prostate lobes. The single-use device is folded into a thin and flexible unit and can be placed with a flexible cystoscope. The Butterfly is designed to be a permanent solution but can also be removed easily under local anesthesia.1
Efficacy and safety
A multicentre trial to assess safety and efficacy is currently in progress.16
SUMMARY
BPH is a common, progressive disease affecting aging men which have a significant impact on patient QoL. In an effort to address the rising demand for BPH therapy that is both effective and safe, innovative technologies promise rapid recovery and symptom relief, low complication rates (especially lower rates of sexual dysfunction), and, ideally, the ability to perform the procedure in an outpatient setting with local anesthesia. Such technologies will also help expand global patient access and democratize urologic BPH care. Current results, especially for TMISTs, will require long-term data to properly assess the safety and durability of outcomes.
