Tag Archive for: WATER trial


Article of the week: Symptom relief and anejaculation after aquablation or transurethral resection of the prostate: subgroup analysis from a blinded randomized trial

Every week, the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an editorial written by a prominent member of the urological community. These are intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation. 

If you only have time to read one article this week, it should be this one.

Symptom relief and anejaculation after aquablation or transurethral resection of the prostate: subgroup analysis from a blinded randomized trial

Mark Plante1, Peter Gilling2, Neil Barber3, Mohamed Bidair4, Paul Anderson5, Mark Sutton6, Tev Aho7, Eugene Kramolowsky8, Andrew Thomas9, Barrett Cowan10, Ronald P. Kaufman Jr11, Andrew Trainer12, Andrew Arther12, Gopal Badlani13, Mihir Desai14, Leo Doumanian14, Alexis E. Te15, Mark DeGuenther16 and Claus Roehrborn17


1University of Vermont Medical Center, Burlington, VT, USA, 2Tauranga Urology Research, Tauranga, New Zealand, 3Frimley Park Hospital, Frimley Health Foundation Trust, Surrey, UK, 4San Diego Clinical Trials, San Diego, CA, USA, 5Royal Melbourne Hospital, Melbourne, Vic., Australia, 6Houston Metro Urology, Houston, TX, USA, 7Addenbrookes Hospital, Cambridge University Hospitals, Cambridge, UK, 8Virginia Urology, Richmond, VA, USA, 9Princess of Wales Hospital, Bridgend, Wales, UK, 10Urology Associates, P.C., Englewood, CO, 11Albany Medical College, Albany, NY, 12Adult Pediatric Urology and Urogynecology, P.C., Omaha, NE, 13Wake Forest School of Medicine, Winston-Salem, NC, 14Institute of Urology, University of Southern California, Los Angeles, CA, 15Weill Cornell Medical College, New York, NY, 16Urology Centers of Alabama, Birmingham, AL, and 17Department of Urology, UT Southwestern Medical Center, University of Texas Southwestern, Dallas, TX, USA




To test the hypothesis that benign prostatic hyperplasia (BPH) robotic surgery with aquablation would have a more pronounced benefit in certain patient subgroups, such as men with more challenging anatomies (e.g. large prostates, large middle lobes) and men with moderate BPH.


We conducted prespecified and post hoc exploratory subgroup analyses from a double‐blind, multicentre prospective randomized controlled trial that compared transurethral resection of the prostate (TURP) using either standard electrocautery vs surgery using robotic waterjet (aquablation) to determine whether certain baseline factors predicted more marked responses after aquablation as compared with TURP. The primary efficacy endpoint was reduction in International Prostate Symptom Score (IPSS) at 6 months. The primary safety endpoint was the occurrence of Clavien–Dindo persistent grade 1 or grade ≥2 surgical complications.


For men with larger prostates (50–80 g), the mean IPSS reduction was four points greater after aquablation than after TURP (P = 0.001), a larger difference than the overall result (1.8 points; P = 0.135). Similarly, the primary safety endpoint difference (20% vs 46% [26% difference]; P = 0.008) was greater for men with large prostate compared with the overall result (26% vs 42% [16% difference]; P = 0.015). Postoperative anejaculation was also less common after aquablation compared with TURP in sexually active men with large prostates (2% vs 41%; P < 0.001) vs the overall results (10% vs 36%; P < 0.001). Exploratory analysis showed larger IPSS changes after aquablation in men with enlarged middle lobes, men with severe middle lobe obstruction, men with a low baseline maximum urinary flow rate, and men with elevated (>100) post‐void residual urine volume.


In men with moderate‐to‐severe lower urinary tract symptoms attributable to BPH and larger, more complex prostates, aquablation was associated with both superior symptom score improvements and a superior safety profile, with a significantly lower rate of postoperative anejaculation. The standardized, robotically executed, surgical approach with aquablation may overcome the increased outcome variability in more complex anatomy, resulting in superior symptom score reduction.

Editorial: A novel robotic procedure for bladder outlet obstruction

We have become used to talking about robotic surgery in urology when we really mean robot‐assisted surgery. The novel aquablation procedure (AquaBeam®) for bladder outlet obstruction (BOO) described by Plante et al. [1] is executed by a robotically controlled waterjet system, conducting a pre‐planned image‐guided resection once the radiological parameters have been entered into the system. This is performed under real‐time ultrasonography guidance. It will deliver a standardized way of carrying out the surgery and will, to a large extent, take away the surgical learning curve whilst introducing a new imaging learning curve.

The present study [1] is an analysis of pre‐planned and exploratory subsets of patients from the WATER study [2], and confirms data from earlier studies [3,4]. The study suggests that, compared with TURP, aquablation is particularly effective in improving both LUTS and bother in the medium‐sized to larger prostate (50–80 mL) and in potentially more challenging prostates such as those with large middle lobes or middle lobe obstruction (judged at pre‐procedure cystoscopy).

It is suggested that the ability to map the resection plane surgically may enable the preservation of key anatomical landmarks and preserve normal sexual function. In this study, anejaculation occurred in only 2% of patients with larger prostates (>50 mL) in the aquablation group compared with 41% of comparable patients undergoing TURP (P < 0.001). The rate of anejaculation however appeared relatively higher in the overall aquablation group, at 10%, compared with 36% in the overall TURP group (P < 0.001). A prostate volume between 30 and 80 mL was an inclusion criterion for the WATER study. This procedure therefore appears to give the best possible rate of anejaculation in a resective surgical intervention in patients with a larger prostate and may have less advantage in patients with a smaller prostate.

Interestingly, the relative overall symptom relief advantage of aquablation over TURP was also not proven in men with smaller prostates; TURP may be equally effective at removing obstructing tissue in smaller as compared to larger prostates. It is not yet clear whether aquablation would not be recommended for prostates below a certain size. In the more recent WATER II study in 101 men with a mean prostate volume of 107 mL, aquablation was also shown to be feasible and safe in men with large prostates (80–150 mL) [5].

There will always be a possible downside to novel treatments and this may relate to poor radiological data entry which may, in turn, lead to sphincter damage, although this has not been an issue in the carefully controlled studies to date. There are also reports of troublesome postoperative bleeding in some cases, although haemostasis can be effectively achieved via a catheter balloon tamponade and traction device or by electrocautery [5,6].

Unlike most other surgical treatments for BOO, the resection times for aquablation are almost independent of prostate volume, although the overall operating time is similar to that of TURP, with the majority of the time being spent in the set up and image planning.

The principal study (WATER) [2] on which this sub‐analysis by Plante et al. is based is an example of a high‐quality randomized controlled trial but still represents data on only 116 patients undergoing aquablation and 65 undergoing TURP; therefore, more randomized controlled trial data and long‐term effectiveness studies are clearly needed. Formal urodynamic studies and trials in patients with even larger prostates would also be appropriate. In addition, there are still few published data on the cost‐effectiveness of aquablation, although it is likely to be in the range of higher‐cost laser ablation therapies.

With better radiology and machine learning or artificial intelligence, this technique may lead to truly standardized BOO surgery with more complete resection and may thereby reduce outcome variability.


  1. Plante, MGilling, PBarber, N et al. Symptom relief and anejaculation after aquablation or transurethral resection of the prostate: subgroup analysis from a blinded randomized trial. BJU Int 2019123651– 60
  2. Gilling, PBarber, NBidair, M et al. WATER: a double‐blind, randomized, controlled trial of Aquablation® vs transurethral resection of the prostate in benign prostatic hyperplasia. J Urol 20181991252– 61
  3. Gilling, PReuther, RKahokehr, A et al. Aquablation ‐ image‐guided robot‐assisted waterjet ablation of the prostate: initial clinical experience. BJU Int 2016117923– 9
  4. Gilling, PAnderson, PTan, AAquablation of the prostate for symptomatic benign prostatic hyperplasia: 1‐year results. J Urol 20171971565– 72
  5. Desai, MBidair, MBhojani, N et al. WATER II (80‐150 mL) procedural outcomes. BJU Int 2019;123106– 12
  6. Aljuri, NGilling, PRoehrborn, CHow I do it: balloon tamponade of prostatic fossa following Aquablation. Can J Urol 2017248937– 40


Article of the week: WATER II (80–150 mL) procedural outcomes

Every week, the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an editorial written by a prominent member of the urological community. These are intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation. 

If you only have time to read one article this week, it should be this one.

WATER II (80–150 mL) procedural outcomes

Mihir Desai*, Mo Bidair, Naeem Bhojani, Andrew Trainer§, Andrew Arther§Eugene Kramolowsky, Leo Doumanian*, Dean Elterman**, Ronald P. Kaufman Jr.††James Lingeman‡‡, Amy Krambeck‡‡, Gregg Eure§§, Gopal Badlani¶¶, Mark Plante***Edward Uchio†††, Greg Gin†††, Larry Goldenberg‡‡‡, Ryan Paterson‡‡‡, Alan So‡‡‡Mitch Humphreys§§§, Claus Roehrborn¶¶¶, Steven Kaplan****, Jay Motola**** and Kevin C. Zorn


*Institute of Urology, University of Southern California, Los Angeles, San Diego Clinical Trials, San Diego, CA, USA, University of Montreal Hospital Centre, University of Montreal, Montreal, QC, Canada, §Adult Paediatric Urology and Urogynecology, P.C., Omaha, NE, Virginia Urology, Richmond, VA, USA, **University Health Network University of Toronto, Toronto, ON, Canada, ††Albany Medical College, Albany, NY, ‡‡Indiana University Health Physicians, Indianapolis, IN, §§Urology of Virginia, Virginia Beach, VA, ¶¶Wake Forest School of Medicine,Winston-Salem, NC, ***University of Vermont Medical Centre, Burlington, VT, †††VA Long Beach Healthcare System, Long Beach, CA, USA, ‡‡‡University of British Columbia, Vancouver, BC, Canada, §§§Mayo Clinic Arizona, Scottsdale, AZ, ¶¶¶Department of Urology, UT Southwestern Medical Centre, University of Texas Southwestern, Dallas, TX and ****Icahn School of Medicine at Mount Sinai, New York, NY, USA


Read the full article



To present early safety and feasibility data from a multicentre prospective study (WATER II) of aquablation in the treatment of symptomatic men with large‐volume benign prostatic hyperplasia (BPH).


Between September and December 2017, 101 men with moderate‐to‐severe BPH symptoms and prostate volume of 80–150 mL underwent aquablation in a prospective multicentre international clinical trial. Baseline demographics and standardized postoperative management variables were carefully recorded in a central independently monitored database. Surgeons answered analogue scale questionnaires on intra‐operative technical factors and postoperative management. Adverse events up to 1 month were adjudicated by an independent clinical events committee.


The mean (range) prostate volume was 107 (80–150) mL. The mean (range) operating time was 37 (15–97) min and aquablation resection time was 8 (3–15) min. Adequate adenoma resection was achieved with a single pass in 34 patients and with additional passes in 67 patients (mean 1.8 treatment passes), all in a single operating session. Haemostasis was achieved using either a Foley balloon catheter placed in the bladder under traction (n = 98, mean duration 18 h) or direct tamponade using a balloon inflated in the prostate fossa (n = 3, mean duration 15 h). No patient required electrocautery for haemostasis at the time of the primary procedure. The mean length of stay after the procedure was 1.6 days (range same day to 6 days). The Clavien–Dindo grade ≥2 event rate observed at 1 month was 29.7%. Bleeding complications were recorded in 10 patients (9.9%) during the index procedure hospitalization prior to discharge, and included six (5.9%) peri‐operative transfusions.


Aquablation is feasible and safe in treating men with large prostates (80–150 mL). The 6‐month efficacy data are being accrued and will be presented in future publications (ClinicalTrials.gov number, NCT03123250).

Read more Articles of the week


Editorial: Aquablating urological skills

Waterjet Ablation Therapy for Endoscopic Resection of prostate tissue (WATER) II (80–150 mL) procedural outcomes by Desai et al. [1] in this issue of the BJUI, reports the results of a robotically controlled cavitating procedure in a multicentre prospective trial that may have wider implications than relief of prostatic hyperplasia causing obstruction.

Management of the large prostate (>80 mL) is often a challenge for many practicing Urologists and requires practice, constant development, and improvement in endoscopic skills. As a result, many differing approaches have been developed and honed, modifying and improving varied skills in the urologist’s armamentarium to equip them to tackle the large prostate. The traditional TURP is recommended only for prostates of 35–80 mL (European Association of Urology [EAU] guidelines 2015). Whilst there are some Urologists who have developed their TURP skills to tackle larger prostates [2], for most other urologists, other procedures have had to be developed to address the very large prostate (>80 mL). As the authors of the paper report, holmium laser enucleation of the prostate (HoLEP) and photoselective vaporisation of the prostate (PVP) have evolved to enable treatment of the larger prostates endoscopically, but have limited penetrance due to the relatively significant learning curve and fellowship training requirements. Open simple prostatectomy (OSP) has good results but significant potential complications [3]. Robot‐assisted simple prostatectomy is being evaluated as another option [4], but requires an expensive robot and extensive training to develop the skill‐set required to perform the procedure. Laparoscopic simple prostatectomy (LSP) also requires extensive training and experience.

The authors [1] report impressive results of aquablation in these usually challenging large prostates. The mean operative time (OT) was 37 min, which is quick for a large prostate. The average length of stay was 1.6 days. The transfusion rate (TR) was 5.9%, which is higher than HoLEP (0–4%) [4], but is lower than OSP, PVP and LSP. It is important to note that the study involved 16 different sites (13 American and three Canadian) and showed that similar results were achieved across all sites irrespective of the experience of the operator, highlighting the very low learning curve for this procedure. Although this was only a single‐arm study with no control group, the authors have endeavoured to provide a comparison of OT, mean hospital stay and TR between aquablation and other procedures (OSP, PVP, HoLEP and LSP; table 5) based on published literature. Complication rates, operative and hospital metrics of aquablation appear to compare favourably with the current accepted means of managing the large prostate.

The use of balloon tamponade for haemostasis appears to hark back to the days of hanging a saline bag attached to an Indwelling Catheter (IDC) off the end of the bed after a monopolar TURP. Bladder traction was maintained for an average of 18 h. The authors report that fulguration was available to the surgeons in this trial, but none chose to use it as they felt that balloon tamponade was an effective haemostatic mechanism. Fulguration was preferentially avoided based on the WATER trial [5], where it was noted that anejaculation rates were twice as large in the aquablation with fulguration compared to the aquablation without fulguration group (16% vs 7%). The company (PROCEPT BioRobotics, Redwood City, CA, USA) even developed a novel catheter tensioning device (CTD) to assist with controlling the tension on the balloon tamponade demonstrating the old adage that ‘Necessity is the mother of Invention’. It would be interesting to see an objective assessment of discomfort from the balloon tamponade in future studies.

The results of this safety and feasibility trial suggest that aquablation is a quick procedure (37 min) for managing very large prostates. The complication rate is comparable to current endoscopic techniques (HoLEP and PVP) and appears superior to more invasive techniques (LSP and OSP). This study only reported perioperative measures and safety outcomes. No functional outcome or effectiveness measures were reported. The initial WATER trial [5] hints at possible effectiveness, but we will have to wait to see the results from this particular cohort of patients with large prostates (WATER II).

The short learning curve hints at a possible future. If the functional results from this cohort of large prostates treated by the aquablation robot compare favourably to current techniques, the patient with the very large prostate will no longer be only treatable by a few surgeons with an advanced and particular skill set.

Is this truly a quick, safe, effective procedure with no learning curve for large prostates? A randomised controlled trial of longer duration to assess functional outcomes, durability and complications may determine if the aquablation robot eventually renders the current surgical skill sets redundant.



  1. Desai M, Bidair M, Bhojani N et al. Aquablation Procedural Outcomes for BPH in Large Prostates (80–150cc): Initial Experience. (WATER II {80‐150 ml} procedural outcomes). BJU Int 2019123: 106–12
  2. Persu C, Georgescu D, Arabagiu I, Cauni V, Moldoveanu C, Geavlete P. TURP for BPH. How large is too large? J Med Life 201015: 376–80
  3. Gratzke C, Schlenker B, Seitz M et al. Complications and early postoperative outcome after open prostatectomy in patients with benign prostatic enlargement: results of a prospective multicenter study. J Urol 2007177: 1419–22
  4. Pokorny M, Novara G, Geurts N et al. Robot‐assisted simple prostatectomy for treatment of lower urinary tract symptoms secondary to benign prostatic enlargement: surgical technique and outcomes in a high‐volume robotic centre. Eur Urol 201568: 451–7
  5. Gilling PJ, Barber NJ, Bidair M et al. WATER: a double‐blind, randomized, controlled trial of aquablation® vs transurethral resection of the prostate in benign prostatic enlargement. J Urol 20185: 1252–61


USANZ 2018: Melbourne

G’day! The 71st  annual USANZ Congress, was held in Melbourne and had the biggest attendance on record for the past 6 years. The Urological Nurse’s congress: ANZUNS ran concurrently, encouraging multi disciplinary learning. An excellent and varied educational programme was masterminded by Declan Murphy, Nathan Lawrentschuk and their organising committee. Melbourne provided a great backdrop and soon felt like home with a rich and busy central business district, cultural and sporting venues, the Yarra river flowing past the conference centre, edgy graffiti and hipster coffee shops, plus too many shops, bars and restaurants to visit.

The programme included a day of masterclasses on a range of subjects, including: urological imaging, advanced robotic surgery with a live case from USC, metastatic prostate cancer and penile prosthetics. These were well attended by trainees and consultants alike. The PCNL session (pictured) with Professor Webb was popular and he generously gave his expertise.  The session was supported by industry and provided an opportunity to use the latest nephroscopes on porcine models and innovative aids to realistically practice different puncture techniques.

Two plenary sessions were held each morning covering the breadth and depth of urology and were well attended. Dr Sotelo is always a highlight; he presented, to an auditorium of collective gasps, a unique selection of ‘nightmare’ cases  His cases gave insight in how intraoperative complications occur and how they can be avoided.  Tips, such as zooming out to reassess in times of anatomical uncertainty during laparoscopy or robotic surgery have great impact when you witness the possible consequences. Tim O’Brien shared his priceless insights on performing IVC thrombectomy highlighting the need for preoperative planning, early control of the renal artery and consideration of pre-embolisation.  His second plenary on retroperitoneal fibrosis provided clarity on the management of this rare condition highlighting the role of PET imaging and, as with complex upper tract surgery, the importance of a dedicated team.

Tony Costello’s captivating presentation covered several myths in robotic prostate surgery, plus the importance of knowing your own outcome figures and a future where robotics will be cost equivalent to laparoscopy. Future technology, progress in cancer genomics and biomarkers were also discussed in various sessions.  One example of new technology was Aquablation of the prostate; Peter Gilling presented the WATER trial results suggesting non-inferiority to TURP.  A welcome addition to the programme was Victoria Cullen (pictured), a psychologist and Intimacy Specialist who provides education, support and strategies for sexual  rehabilitation. She described her typical consultation with men with sexual dysfunction and how to change worries about being ‘normal’ to focusing on what is important to the individual.

Joint plenary sessions with the AUA and EAU were a particular highlight. Prof Chris Chapple confirmed the need for robust, evidence guidelines which support clinical decision making; and in many cases can be used internationally. He suggested collaboration is crucial between us as colleagues and scientists working in the field of urology. Stone prevention and analysis of available evidence was described by Michael Lipkin; unfortunately stone formers are usually under-estimaters of their fluid intake so encouragement is always needed! Amy Krambeck presented evidence for concurrent use of anticoagulants and antiplatelets during BOO surgery and suggested there can be a false sense of security when stopping these medications as it isn’t always safe. She championed HoLEP as her method of BOO surgery and continues medications, although the evidence does show blood transfusion rate may be higher. She also uses a fluid warming device which has less bleeding and therefore improved surgical vision; importantly it is preferred by her theatres nurses! MRI of the prostate was covered  by many different speakers, however Jochen Walz expertly discussed the limitations of MRI in particular relating negative predictive value (pictured). He eloquently explained the properties of cribiform Gleason 4 prostate cancer and how this variant contributed to the incidence of false negatives.

Moderated poster and presentation sessions showcased research and audit projects from the UK, Australia, New Zealand and beyond, mainly led by junior urologists. The best abstracts submitted by USANZ trainees were invited to present for consideration of Villis Marshall and Keith Kirkland prizes. These prestigious prizes were valiantly fought for and reflected high quality research completed by the trainees. Projects included urethral length and continence, no need for lead glasses, obesity and prostate cancer, multi-centre management of ureteric calculi, mental health of surgical trainees and seminal fluid biomarkers in prostate cancer. This enthusiasm for academia will undoubtedly stand urology in good stead for the future; this line up (pictured) is one to watch!

The Trade hall provided a great networking space to be able to meet with friends and colleagues and engage with industry. It also hosted poster presentation sessions, with a one minute allocation for each presenter – which really ensures a succinct summary of the important findings (pictured)! It was nice to meet with Australian trainees and we discussed the highs and lows of training and ideas for fellowships. Issues such as clinical burden and operative time, selection into the specialty, cost of training, burn out and exam fears were discussed and shared universally; however there is such enthusiasm, a passion for urology and inspirational trainers which help balance burdens that trainees face. Furthermore, USANZ ‘SET’ Trainees were invited to meet with the international faculty in a ‘hot seat’ style session which was an enviable opportunity to discuss careers and aspirations.

In addition to the Congress I was fortunate to be invited for a tour and roof-top ‘barbie’ at the Peter Mac Cancer centre; plus a visit to Adelaide with Rick (Catterwell, co-author) seeing his new hospital and tucking into an inaugural Aussie Brunch. Peter Mac and Royal Adelaide Hospital facilities indicated an extraordinary level of investment made by Federal and State providers; the Peter Mac in particular had impressive patient areas, radiotherapy suites and ethos of linking clinical and research. However beyond glossy exteriors Australian public sector clinicians voiced concerns regarding some issues similar to those we face in the NHS.

Despite the distance of travelling to Melbourne and the inevitable jet lag the world does feels an increasingly smaller place and the Urological world even more so. There is a neighbourly relationship between the UK, Australia and New Zealand as evidenced by many familiar faces at USANZ who have worked between these countries; better for the new experiences and teaching afforded to them by completing fellowships overseas. The Gala Dinner was a great chance to unwind, catch up with friends and celebrate successes in the impressive surrounding of Melbourne Town Hall (pictured); the infamous organ played particularly rousing rendition of Phantom of the Opera on arrival.

The enthusiasm to strive for improvement is similar both home and away and therefore collaboration both nationally and internationally is integral for the progress of urology. The opening address by USANZ President included the phrase ‘together we can do so much more’ and this theme of collaboration was apparent throughout the conference. The future is bright with initiatives led by enthusiastic trainee groups BURST and YURO to collect large volume, high quality data from multiple centres, such as MIMIC which was presented by Dr Todd Manning. Social media, telecommunications and innovative technology should be used to further the specialty, especially with research and in cases of rare diseases – such as RPF.  Twitter is a tool that can be harnessed and was certainly used freely with the hashtag #USANZ18. Furthermore, utilisation of educational learning platforms such as BJUI knowledge and evidence based guidelines help to facilitate high quality Urological practice regardless of state or country.

So we’d like to extend a huge thank you to Declan, Nathan and the whole team, and congratulate them for a successful, educational and friendly conference; all connections made will I’m sure last a lifetime and enable us to do more together.

Sophie Rintoul-Hoad and Rick Catterwell


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