Tag Archive for: aotw-23-01-19


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




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).


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


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