Interventional procedure overview of transurethral water-jet ablation for lower urinary tract symptoms caused by benign prostatic hyperplasia
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Evidence summary
Population and studies description
This interventional procedures overview is based on approximately 3,300 patients from 1 pooled analysis of 4 trials (Elterman 2021), 1 randomised controlled trial reported in 2 publications (the trial is also included in the pooled analysis; Gilling 2020 and 2022), 1 prospective multicentre single-arm trial (also included in the pooled analysis; Zorn 2021), 1 retrospective cohort study (Helfand 2021), 1 retrospective non-randomised comparative study (Gloger 2021) and 2 retrospective case series (1 of which also included data from the 4 trials in the pooled analysis; Elterman 2021 and 2020). There was also a report from the FDA MAUDE database (Kaplan-Marans 2021). There is some patient overlap between the studies. This is a rapid review of the literature, and a flow chart of the complete selection process is shown in figure 1. This overview presents 9 studies as the key evidence in table 2 and table 3, and lists 53 other relevant studies in table 5.
The 9 key studies included data from Europe, Asia and North America and treatment dates ranged from 2014 to 2021.
The pooled analysis by Elterman et al. (2021) included 425 men with moderate to severe LUTS attributable to BPH. Data on water-jet ablation was analysed from 1 randomised controlled trial (WATER), 2 prospective multicentre single-arm trials (WATER II and FRANCAIS WATER) and a prospective multicentre observational study (OPEN WATER), all of which had at least 1 year follow up. Prostate size varied between the 4 studies and ranged from 20 to 150 ml. Publications with longer term outcomes for WATER and WATER II have been included separately in tables 2 and 3 (Gilling 2020 and 2022, Zorn 2021).
In the WATER trial, 181 men with prostate size between 30 and 80 ml were randomised to have either water-jet ablation (n=116) or TURP (n=65). Outcomes were reported at 3 and 5 years follow up. Patients and follow-up assessors were blinded to treatment assignment up to 3 years, at which point patients were unblinded. The authors noted that the 4- and 5-year follow-up visits were during the pandemic caused by COVID-19 and longer term outcomes were available for fewer men than anticipated (50% of men in the water-jet group and 49% in the TURP group had 5-year follow-up data; Gilling 2020 and 2022).
The WATER II trial was a prospective multicentre single-arm trial including 101 men with prostate size between 80 and 150 ml (3-year follow up was available for 78 men; Zorn 2021).
The study by Kaplan-Marans et al. (2021) was a comparison of device-related adverse events in the FDA MAUDE database associated with 3 procedures used to treat BPH (water-jet ablation, prostatic urethral lift and transurethral water-vapour therapy). A total of 391 adverse events were described between 2015 and 2020. The MAUDE database includes mandatory reports from manufacturers and device importers when a device may have caused injury to a patient, and voluntary reports from other sources, including healthcare professionals and patients. Limitations of the database include under-reporting, duplicate reporting, incomplete reports and uncertainty if the device caused the complication being described. The true denominator for these events is not captured and the database is not designed to calculate or compare complication rates.
The study by Helfand et al. (2021) was a retrospective cohort study of 251 men, comparing outcomes for different size prostates. A group of 34 men with very large prostates (defined as more than 150 ml) were compared with men with large (n=101) or average size (n=116) prostates who were included in the WATER and WATER II studies. The mean follow up for the men with very large prostates was 7 months.
The study by Gloger et al. (2021) was a retrospective, single centre non-randomised comparative study including 167 men who had water-jet ablation with subsequent selective bipolar cauterisation and 215 men who had HoLEP. The primary aim of the study was to assess the risk of perioperative bleeding complications. Two other retrospective studies also focused on perioperative bleeding and strategies for its management. One was a case series of 2,089 men with prostate size ranging from 20 to 363 ml (Elterman 2021b), all of whom had non-resective focal cautery at the bladder neck after water-jet ablation. The other was a case series of 801 men, including data from the 4 trials described in the pooled analysis, which compared transfusion rates between different haemostasis methods (Elterman 2020).
Table 2 presents study details.
Study no. | First author, date country | Patients | Mean age (years) | Study design | Inclusion criteria | Intervention | Follow up |
|---|---|---|---|---|---|---|---|
1 | Elterman D, 2021a US, UK, Australia, New Zealand, Canada, France, Germany, Lebanon | n=425 | not reported for whole cohort | Pooled analysis of 4 trials (WATER, WATER II, FRANCAIS WATER, OPEN WATER). Study dates were between 2015 and 2019. | Prospective multicentre studies of water-jet ablation with at least 1 year follow up. All men had moderate to severe LUTS caused by BPH and prostate size ranged from 20 to 150 ml. | Only results for water-jet ablation (n=425) were analysed. Device: AQUABEAM robotic system (PROCEPT BioRobotics, US) | 1 year |
2, 3 | Gilling P, 2020 and 2022 US, UK, Australia, New Zealand | n=181 Mean prostate size 53 ml | 66 | Randomised controlled trial (WATER trial). Enrolment was between 2015 and 2016. | Men aged 45 to 80 years with a prostate size 30 to 80 ml, moderate to severe symptoms (IPSS 12 or higher) and Qmax less than 15 ml/second. |
Device for water-jet ablation: AQUABEAM (PROCEPT BioRobotics, US) | 3 and 5 years |
4 | Zorn K, 2021 US, Canada | n=101 (78 with 3-year follow up) Mean prostate size 107 ml | 68 | Prospective multicentre single-arm trial (WATER II). Enrolment was in 2017. | Men aged 45 to 80 were included if they had a prostate volume between 80 and 150 ml by TRUS, baseline IPSS 12 or higher, Qmax less than 15 ml/second, a serum creatinine less than 2 mg/dl, a history of inadequate or failed response to medical therapy and mental capability, and willingness to participate in the study. Men were excluded if they had body mass index 42 kg/m2 or higher, a history of prostate or bladder cancer, clinically significant bladder calculus or bladder diverticulum, active infection, previous urinary tract surgery, urinary catheter use daily for 90 or more days, chronic pelvic pain, diagnosis of urethral stricture, meatal stenosis or bladder neck contracture, use of anticholinergic agents, and other general conditions that could prevent adequate study follow up. Men with urinary retention were excluded if the catheter was in place for more than 90 days. | Water-jet ablation using AQUABEAM (PROCEPT BioRobotics, US). For larger prostates, 2 passes of the AQUABEAM probe were typically used. Catheter traction was held for an average of 18 hours. Electrocautery was not used for haemostasis in any of the procedures. | 3 years |
5 | Kaplan-Marans E, 2021 US | 391 adverse events (102 for water-jet ablation) | Not reported | Registry (MAUDE database). Reports between 2015 and 2020 were included. | The MAUDE database was queried using the terms 'Aquabeam', 'Rezum' and 'UroLift' for adverse events reported between January 2015 and July 2020. |
| Not reported |
6 | Helfand B, 2021 US, Canada | n=251 (34 with very large prostates, 101 with large and 116 with average size prostates) | 69 for men with very large prostates | Retrospective cohort study, comparing outcomes for different size prostates. | Men with prostates larger than 150 ml (defined as very large) were compared with men with large or average size prostates who were included in the WATER or WATER II studies. | Water-jet ablation. Device: AQUABEAM system (PROCEPT BioRobotics, US). | 6 months (mean 7 months in group with very large prostates) |
7 | Gloger S, 2021 Germany | n=382 Mean prostate size 56 ml (water-jet ablation) and 95 ml (HoLEP); p<0.001 | 64.7 for water-jet ablation, 70.8 for HoLEP, p<0.001 | Retrospective single centre, non-randomised comparative study. Procedures were done between 2018 and 2020. | Men who had water-jet ablation between 2018 and 2020 were compared with men who had HoLEP at the same centre during the same period. The first 20 men to have water-jet ablation were excluded to take account of the learning curve. |
Device for water-jet ablation: AQUABEAM system (PROCEPT BioRobotics, US). | 6 weeks |
8 | Elterman D, 2021b 11 countries (Asia, Europe, North America) | n=2,089 Mean prostate size 87 ml | Not reported | Retrospective case series. Procedures were done between 2019 and 2021. | Consecutive patients who had water-jet ablation between 2019 and 2021. Prostate size ranged from 20 to 363 ml. | Water-jet ablation followed by non-resective focal cautery at the bladder neck. Device: AQUABEAM system (PROCEPT BioRobotics, US). | Not reported |
9 | Elterman D, 2020 | n=801 Mean prostate size 67 ml (range 20 to 280 ml) | Not reported | Retrospective case series (including data from WATER, WATER II, FRANCAIS WATER and OPEN WATER). Procedures were done between 2014 and 2019. | Data from 7 clinical studies, sponsored by PROCEPT BioRobotics, along with 4 high-volume early commercial users of the technology were included. The procedures were done between 2014 and early 2019. | Water-jet ablation with different haemostasis techniques. Method of traction was defined as robust (using a catheter-tensioning device) or standard (taping the catheter to the leg, gauze knot synched up to the meatus, or no traction at all). Device: AQUABEAM system (PROCEPT BioRobotics, US). | Not reported |
First author, date | Efficacy outcomes | Safety outcomes |
|---|---|---|
Elterman, 2021 | Mean procedure time, defined as TRUS insertion to urinary catheter placement, was 40 minutes (median 38, range 8 to 111 minutes). Mean improvement in IPSS from baseline to 1 year=16 points There was no variation across studies and 1-year scores were independent of baseline scores. Mean IPSS QoL improved from 4.7 at baseline to 1.4 at 1 year. There was no variation in baseline IPSS QoL or 1-year change score across studies. Mean Qmax at 1 year was 20.5 ml/second, an improvement of 9.4 ml/second from baseline. The 1-year change was independent of studies. Mean improvement in PVR at 1 year=62 ml (median 41 ml) The improvement in PVR was strongly dependent on baseline PVR and was largest in the WATER II study. Improvements in IPSS, IPSS QoL, Qmax and PVR were independent of both prostate size and presence or absence of median lobe. Improvements in both Qmax and PVR were large and clinically important across all subgroups. Surgical retreatment=0.7% (95% CI 0.1% to 2.0%) | There were no reports of postoperative de novo erectile dysfunction, whereas postoperative de novo ejaculatory dysfunction, defined as losing the ability to emit seminal fluid, was observed in 10.8% of men. Clavien-Dindo grade 2 to 4 adverse events were similar across studies. In the only randomised study, the Clavien-Dindo grade 2 to 4 adverse events were similar between water-jet ablation and TURP. Men with low baseline ISI scores (4 or less) had modest perioperative rises in ISI score, but values reduced back to baseline with all prostate volumes. In men with clinically significant incontinence (baseline score above 4), ISI scores improved in men with both small and large prostates. |
Gilling, 2020 and 2022 | Change in IPSS from baseline to 6 months (primary efficacy endpoint)
p<0.0001 for non-inferiority, p=0.1346 for superiority Outcomes at 3-year follow up At 3 years, there were 97 patients in the water-jet ablation group and 55 patients in the TURP group. IPSS reduction, mean (SD)
p=0.6848 for difference between groups 78% of men in the water-jet ablation group and 82% of men in the TURP group had improvements of at least 5 points from baseline. For men with larger prostates (50 ml or above), the mean reduction was 3.5 points higher in the water-jet ablation group compared with the TURP group (p=0.0125). Improvement in IPSS QoL score, mean (SD)
p=0.7845 for difference between groups Improvements in Qmax, mean (SD)
Mean reduction in PSA
p=0.5983 for difference between groups Medical failure (defined as started on alpha blocker or 5-alpha reductase inhibitors after surgery)
Outcomes at 5-year follow up At 5 years, there were 58 patients in the water-jet ablation group and 32 patients in the TURP group. IPSS reduction, mean (SD)
p=0.2764 for difference between groups For men with larger prostates (50 ml or more), the IPSS reduction was 3.5 points greater in the water-jet ablation group compared with TURP (p=0.0123). IPSS QoL score (mean 4.8 at baseline)
Improvements in Qmax, mean (SD)
Additional treatment for BPH
Mean reduction in PSA
p=0.465 for difference between groups | Rate of adverse events at 3 months
p=0.0149 for superiority Persistent Clavien-Dindo grade 1 events at month 3
Rate of grade 2 and above events at month 3
Urethral stricture at 3 years
Procedure-related anejaculation
There were no de novo erectile dysfunction events or incontinence events needing a pad in either arm. Changes in MSHQ-EjD were close to 0 for all time points up to 5 years in the water-jet ablation group. Average changes were 2.7 points lower (worse) in the TURP group (p=0.0015). |
Zorn, 2021 | IPSS, mean (SD)
3-year IPSS scores were independent of both baseline IPSS and prostate size. IPSS QoL, mean (SD)
In patients reporting catheter use in the 45 days before enrolment, IPSS decreased from 26.3 (7.4) at baseline to 3.7 (2.4) at 3-year follow up. No patient using a catheter before surgery had to return to using a catheter postoperatively. Improvements in LUTS were described as clinically important. Qmax, mean (SD)
PVR urinary volume, mean (SD)
PSA, mean (SD)
In men not taking 5-alpha-reductase inhibitors before surgery, PSA was decreased substantially at 3 years (p<0.0001). Additional treatment for BPH At 3-year follow up, 6% of treated patients needed BPH medication and an additional 3% needed surgical retreatment. | Adverse events within 6 months
Adverse events at 6 to 12 months
Adverse events at 12 to 36 months
|
Kaplan-Marans, 2021 | No efficacy data were reported. | Number and severity of adverse events
Notable complications
Water-jet device malfunctions included motion error (n=8), handpiece fracture or attachment malfunction (n=8), scope fracture (n=3), low pressure pump error (n=2), revolutions per minute dysfunction error (n=2), and aspiration and irrigation tube detachment from manifold (n=1). |
Helfand, 2021 | Mean operative time, minutes
Mean IPSS in men with very large prostates
Mean Qmax in men with very large prostates
Clinical outcomes were similar regardless of prostate volume (p=0.56 for IPSS and 0.74 for Qmax at follow up). Mean decrease in PSA level
| There were no reports of incontinence, erectile dysfunction, or ejaculatory dysfunction in the group of men with very large prostates. There were no periprocedural blood transfusions needed in the group of men with very large prostates. 2 of the men with very large prostates had low grade prostate cancer documented on submitted pathological tissue. |
Gloger, 2021 | Mean operative time
Difference was described as statistically significant, but p value was not reported. Mean length of hospital stay (days)
Catheter time (days)
| Transurethral revision surgery because of bleeding within 6 weeks of procedure
Most were within the first 10 days after the procedure. Mean perioperative drop in haemoglobin
Need for transfusion
Bleeding-related rehospitalisation
Subgroup analysis showed no statistically significant differences in haematuria-related complications and need for transfusion according to prostate volume. |
Elterman, 2021b | Mean time from removing handpiece to inserting the urinary catheter was 19.9 minutes. | Postoperative bleeding needing transfusion=0.8% (17/2,089; 95% CI 0.5 to 1.3%) None of these were more than 3 days after the procedure. The average number of units given was 2. 24% (4/17) of the transfusions were in patients who were on anticoagulant or antiplatelet therapy. 88% of transfusions happened before a surgeon's sixth water-jet ablation procedure. Return to operating theatre for fulguration to address bleeding=0.6% (12/2,089; 95% CI 0.3 to 1.0%) |
Elterman, 2020 | No efficacy data were reported. | Transfusion=3.9% (31/801) Most were before hospital discharge and none were more than 30 days after the procedure. Transfusion rate in small volume prostates (mean 35 ml, range 20 to 48 ml)
Transfusion rate in medium volume prostates (mean 62 ml, range 48 to 77 ml)
Transfusion rate in large volume prostates (mean 104 ml, range 77 to 280 ml)
|
Procedure technique
All the studies used the AQUABEAM system (PROCEPT BioRobotics, US) for water-jet ablation. Different techniques were used to achieve haemostasis at the end of the procedure.
Efficacy
IPSS
IPSS was reported as an outcome measure in 4 studies. In the pooled analysis of 4 trials, the mean improvement in IPSS from baseline was 16 points at 1-year follow up and the mean IPSS QoL score improved from 4.7 at baseline to 1.4 at 1 year (Elterman 2021).
In the randomised controlled trial of 181 men (also included in the pooled analysis), the mean reduction in IPSS was 14.4 points (64% reduction) for those who had water-jet ablation (n=97) and 13.9 points (61% reduction) for those who had TURP (n=55) at 3-year follow up (p=0.6848 between groups). The mean IPSS QoL score improved by 3.2 points in both groups (p=0.7845 between groups). At 5 years, the mean reduction was 15.1 points in the water-jet ablation group (n=58) and 13.2 points in the TURP group (n=32; p=0.2764 between groups). For men with larger prostates (50 ml or more) the IPSS reduction was 3.5 points greater in the water-jet ablation group compared with TURP (p=0.0123). The mean IPSS QoL score improved from 4.8 at baseline to 1.6 in both groups (Gilling 2020 and 2022).
In the prospective single-arm trial of 101 men (also included in the pooled analysis), the mean IPSS reduced from 23.2 at baseline to 6.5 at 3-year follow up (p<0.0001). The mean IPSS QoL score improved from 4.6 at baseline to 1.1 at 3‑year follow up (p<0.0001; Zorn 2021). In the retrospective cohort study of 251 men, the mean IPSS for men with very large prostates reduced from 19 at baseline to 7 at follow up (mean 7 months, p<0.001; Helfand 2021).
Qmax
Qmax was reported as an outcome measure in 4 studies. In the pooled analysis of 4 trials, the mean improvement in Qmax from baseline was 9.4 ml/second at 1-year follow up (Elterman 2021).
In the randomised controlled trial of 181 men (also included in the pooled analysis), the mean improvement in Qmax was 11.6 ml/second for those who had water-jet ablation (n=97) and 8.2 ml/second for those who had TURP (n=55) at 3-year follow up (p=0.0848 between groups). At 5 years, the mean improvement was 8.7 ml/second in the water-jet ablation group (n=58; 125% improvement) and 6.3 ml/second in the TURP group (n=32; 89% improvement; Gilling 2020 and 2022).
In the prospective single-arm trial of 101 men (also included in the pooled analysis), the mean Qmax improved from 8.7 ml/second at baseline to 18.5 ml/second at 3-year follow up (p<0.0001; Zorn 2021). In the retrospective cohort study of 251 men, the mean Qmax for men with very large prostates reduced from 7 ml/second at baseline to 19 ml/second at follow up (mean 7 months, p<0.001; Helfand 2021).
PVR
PVR was reported as an outcome measure in 2 studies. In the pooled analysis of 4 trials, the mean improvement in PVR from baseline was 62 ml at 1-year follow up. The improvement in PVR was strongly dependent on baseline PVR (Elterman 2021). In the prospective single-arm trial of 101 men (also included in the pooled analysis), the mean PVR had improved to 51 ml at 3-year follow up compared with 131 ml at baseline (p value not reported; Zorn 2021).
PSA
PSA was reported as an outcome measure in 3 studies. In the randomised controlled trial of 181 men, there was a statistically significant mean reduction in PSA level of 0.9 ng/dl for those who had water-jet ablation (n=97; p=0.0018 compared with baseline) and 1.1 ng/dl for those who had TURP (n=55; p=0.002 compared with baseline) at 3-year follow up (p=0.5983 between groups). At 5 years, the mean reduction was 1.0 ng/dl in the water-jet ablation group (n=58; p=0.0658 compared with baseline) and 0.5 ng/dl in the TURP group (n=32; p=0.2969 compared with baseline and p=0.465 between groups; Gilling 2020 and 2022).
Need for additional treatment
The need for additional medical or surgical treatment was reported in 3 studies. In the pooled analysis of 4 trials, the rate of surgical retreatment after 1 year was 0.7% (95% CI 0.1% to 2.0%; Elterman 2021). In the randomised controlled trial of 181 men, medical failure (defined as started on alpha blocker or 5-alpha reductase inhibitors after the procedure) was reported for 9% of men who had water-jet ablation and 14% of men who had TURP at 3-year follow up. At 5 years, 6% (7/116) of men who had water-jet ablation group needed additional treatment (5 TURP, 1 laser and 1 medication) compared with 12% (8/65) in the TURP group (7 medication, 1 TURP; Gilling 2020 and 2022). In the prospective single-arm trial of 101 men, 6% of men needed BPH medication and an additional 3% needed surgical retreatment at 3-year follow up (Zorn 2021).
Safety
Unspecified adverse events
The rate of Clavien-Dindo grade 2 and above events within the first 3 months was similar for water-jet ablation (20%) and TURP (23%) in the randomised controlled trial of 181 men (p=0.3038). The rate of grade 1 events was statistically significantly lower in the water-jet ablation group (7% compared with 25%, p=0.0004; Gilling 2020 and 2022).
In the study by Kaplan-Marans et al. (2021) there were 102 events associated with aquablation, 132 associated with prostatic urethral lift and 157 associated with transurethral water-vapour therapy reported on the FDA MAUDE database during the same time period (2015 to 2020). Of the reported events, there were 79 (78%) described as severe or life-threatening for water-jet ablation, 69 (52%) for prostatic urethral lift and 24 (15%) for transurethral water-vapour therapy.
Urethral stricture
Urethral stricture was reported as an adverse event in 2 studies. It was reported in 1% (1/116) of men who had water-jet ablation and 6% (4/65) of men who had TURP at 3-year follow up in the randomised controlled trial of 181 men (Gilling 2020 and 2022). Urethral stricture was reported in 1 man within 6 months of the procedure in the single-arm trial of 101 men. In the same study, meatal stenosis was reported in 3% (3/101) of men within 6 months of the procedure (Zorn 2021).
Rectal perforation
The FDA MAUDE database included 4 reports of rectal perforation. These were evaluated by the manufacturer and were thought to be caused by operator misuse (Kaplan-Marans 2021).
Bleeding
Bleeding or the need for blood transfusion was reported as an adverse event in 5 studies, including 3 that were specifically focused on perioperative bleeding.
Periprocedural blood transfusion was reported in 6% (6/101) of men and delayed transfusion within 30 days was reported in 4% (4/101) men in the single-arm trial of 101 men. Fulguration without transfusion was reported in 3% (3/101) of men within 6 months. In the same study, a bleeding event that did not need transfusion or return to theatre was reported in 2% (2/101) of men within 6 months, 2% (2/101) of men between 6 and 12 months and 5% (5/101) of men between 12 and 36 months (Zorn 2021).
Transurethral revision surgery because of bleeding within 6 weeks of the procedure was reported in 13% of men who had water-jet ablation and 10% of men who had HoLEP (p=0.329) in the non-randomised comparative study of 382 men (Gloger 2021). Most of these were within the first 10 days of the procedure. In the same study, none of the men who had water-jet ablation and 1 man who had HoLEP needed a transfusion. Bleeding-related readmission to hospital was reported for 4% (6/157) of men who had water-jet ablation and 6% (12/215) of men who had HoLEP (p=0.468).
Postoperative bleeding needing transfusion was reported in 1% (17/2,089) of men in the case series of 2,089 men, all of which were within 3 days of the procedure (Elterman 2021b). Return to theatre for fulguration to address bleeding was reported for 1% (12/2,089) of men. In the case series of 801 men, transfusion was reported in 4% (31/801), most of which were before hospital discharge (Elterman 2020). The risk of transfusion increased as prostate volume increased. Predicted haemoglobin changes were lowest when standard traction was used along with bladder neck cautery.
There were 32 reports of blood transfusion included in the list of notable complications associated with water-jet ablation described in the FDA MAUDE database (Kaplan-Marans 2021).
Sexual function
Rates of ejaculatory or erectile dysfunction after the procedure were reported in 4 studies.
Postoperative de novo ejaculatory dysfunction, defined as losing the ability to emit seminal fluid, was reported in 11% of men in the pooled analysis of 425 men (Elterman 2021). There were no reports of postoperative de novo erectile dysfunction.
Procedure-related anejaculation was reported in 7% of men who had water-jet ablation and 25% of men who had TURP (p=0.0004) in the randomised controlled trial of 181 men. Changes in MSHQ-EjD were close to 0 for all time points up to 5 years in the water-jet ablation group compared with a mean decrease of 2.7 points in the TURP group (p=0.0015). Erectile function, as measured by the IIEF-5, showed no statistically significant changes in either group through 5 years (Gilling 2020 and 2022).
Ejaculatory dysfunction was reported in 15% (15/101) of men within 6 months, 1% (1/101) between 6 and 12 months and 2% (2/101) at 12 to 36 months after the procedure in the single-arm trial of 101 men. Erectile dysfunction was reported in 2 men, both at 12 to 36 months after the procedure (Zorn 2021).
There were no reports of erectile dysfunction or ejaculatory dysfunction in the 34 men with very large prostates included in the cohort study of 251 men (Helfand 2021).
Urinary incontinence
Urinary incontinence was reported in 3 studies, 2 of which stated that incontinence scores had improved or that there were no reports of incontinence after the procedure.
In the pooled analysis of 425 men it was noted that men with low baseline ISI scores (4 or less) had modest perioperative rises in ISI score, but values reduced back to baseline with all prostate volumes. In men with clinically significant incontinence (baseline score above 4), ISI scores improved (Elterman 2021a). Urinary incontinence was reported in 7% (7/101) of men within 6 months, 1% (1/101) of men at 6 to 12 months and 1% (1/101) of men at 12 to 36 months after the procedure in the single-arm trial of 101 men. Urinary frequency and urinary urgency were reported in 2% (2/101) of men each at 6 months, urinary urgency was reported in 2% (2/101) of men between 6 and 12 months, and urinary frequency was reported in 5% (5/101) of men and urinary urgency was reported in 3% (3/101) of men at 12 to 36 months after the procedure. Dysuria was also reported in 3% (3/101) of men within 6 months of the procedure (Zorn 2021).
There were no reports of incontinence in the 34 men with very large prostates included in the cohort study of 251 men (Helfand 2021).
Urinary retention
Urinary retention was reported as an adverse event in 1 study. It was reported in 4% (4/101) of men within 36 months after the procedure in the single-arm trial of 101 men (Zorn 2021).
Urinary tract infection
Urinary tract infection was reported as an adverse event in 1 study. It was reported in 7% (7/101) of men within 6 months, 8% (8/101) at 6 to 12 months and 5% (5/101) at 12 to 36 months after the procedure in the single-arm trial of 101 men (Zorn 2021).
Device malfunction
Reports of water-jet device malfunctions were described in the FDA MAUDE database review. These included motion error (n=8), handpiece fracture or attachment malfunction (n=8), scope fracture (n=3), low pressure pump error (n=2), revolutions per minute dysfunction error (n=2), and aspiration and irrigation tube detachment from manifold (n=1; Kaplan-Marans 2021).
Other
Additional adverse events were reported in the single-arm trial of 101 patients. These included cardiac events (3%), cerebrovascular accident (1%), pain (1%), skin infection (1%), bladder stones (3%), haematospermia (1%) and chronic cystitis (1%; Zorn 2021).
The review of events described on the FDA MAUDE database included the following additional complications: haematuria, clot evacuation or irrigation, arterial embolisation, laparotomy, prostatic capsule perforation and deep vein thrombosis or pulmonary embolism (Kaplan-Marans 2021).
Anecdotal and theoretical adverse events
Expert advice was sought from consultants who have been nominated or ratified by their professional society or royal college. They were asked if they knew of any other adverse events for this procedure that they had heard about (anecdotal), which were not reported in the literature. They were also asked if they thought there were other adverse events that might possibly occur, even if they had never happened (theoretical).
They described no additional anecdotal adverse events.
They described damage to the bladder neck or sphincter as a theoretical adverse event.
Three professional expert questionnaires for this procedure were submitted. Find full details of what the professional experts said about the procedure in the specialist advice questionnaires for this procedure.
Validity and generalisability
The evidence includes data from the UK.
The evidence includes a randomised, double-blinded controlled trial, comparing water-jet ablation to TURP.
Prostate size varied between studies and the randomised controlled trial only included prostates between 30 and 80 ml. Across all studies, prostate volume ranged from 20 ml to 363 ml.
Some of the evidence was from early use of the technology and the methods used to achieve haemostasis have changed over time.
The randomised controlled trial included some outcome data to 5 years, which is the longest follow up reported. The authors noted that this was available for a relatively low proportion of men who were enrolled in the study, because the 4 and 5-year follow-up visits coincided with the pandemic caused by COVID-19 (Gilling 2022).
All 4 studies included in the pooled analysis by Elterman et al. (2021) were sponsored by the device manufacturer. These included the studies by Gilling et al. (2020 and 2022) and Zorn (2021). Authors of the studies by Helfand et al. (2021) and Elterman et al. (2021b) declared a consulting agreement with the device manufacturer, although no funding was provided for the research. Potential conflicts of interest were not reported in the study by Gloger et al. (2021). All authors of the study by Elterman et al. (2020) were investigators for the device manufacturer and data was included from the manufacturer-sponsored trials.
Ongoing trials:
WATER III: A Randomized, Controlled Trial of Aquablation versus Transurethral Laser Enucleation of Large Prostates (80 to 180mL) in Benign Prostatic Hyperplasia (NCT04801381); Germany; n=200; estimated study completion date December 2027.
Aquablation versus Holmium Laser Enucleation of the Prostate in the Treatment of Benign Prostatic Hyperplasia in Medium to Large Size Prostates: A Prospective Randomized Trial (NCT04560907); Switzerland; n=120; estimated study completion date November 2027.
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