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Overview and Technological Evolution of Aquablation Therapy

• Definition and Core Technology: Aquablation therapy is an image-guided, robotic-assisted, heat-free waterjet resective procedure designed to resect obstructive prostate tissue caused by Benign Prostatic Hyperplasia (BPH) while preserving critical surrounding anatomical structures.

• Regulatory Milestones and Adoption Timeline:

  • 2017: Initial FDA Clearance granted for the AquaBeam® Robotic System.

  • 2018: Medicare coverage established across the United States.

  • 2019: Official commercial launch in the United States market.

  • 2020: Inclusion into the American Urological Association (AUA) Guidelines.

  • 2021: Inclusion into the European Association of Urology (EAU) Guidelines.

  • 2022: Guideline inclusions by the National Institute for Health and Care Excellence (NICE) and the Canadian Urological Association (CUA).

  • 2023: Installation of the $400\text{th}$ AquaBeam system in the United States.

  • 2024: FDA Clearance of the next-generation platform, the HYDROS™ Robotic System.

• Clinical Impact Metrics:

  • Over $50{,}000$ patients treated globally.

  • Over $400$ robotic systems installed across the United States.

  • Over $1{,}000$ urologists trained on the platform.

  • Comprehensive reimbursement coverage secured through Medicare and major commercial payers, representing $95\%$ of insured men in the United States.

BPH Epidemiology and Market Dynamics

• Epidemiology of BPH:

  • BPH represents the primary reason men seek care from a urologist.

  • Prevalence scales significantly with age: $50\%$ of men aged $51\text{--}60$ years, and $90\%$ of men aged $80\text{--}90$ years, present with BPH.

  • Approximately $40{,}000{,}000$ men in the United States are currently living with BPH.

• Actively Managed Patient Population Breakdown ($12{,}000{,}000+$ Men Annually):

  • $4.3$ Million Watchful Waiters: Patients who forego medical or surgical intervention and continue experiencing lower urinary tract symptoms (LUTS).

  • $6.7$ Million Pharmaceutical Patients: Patients maintained on oral medical therapy who experience side effects and require ongoing dose adjustments.

  • $1.1$ Million Pharmaceutical Fallout Patients: Patients who delay surgical intervention despite medication failure.

  • $400{,}000$ Annual Surgical Patients: Patients undergoing surgical interventions, historically required to compromise between safety and efficacy profiles.

• Prostate Volume Classifications and Historical Surgical Compromises:

  • Small Prostates: $30\text{--}40\,mL$

  • Medium Prostates: $40\text{--}80\,mL$

  • Large Prostates: $80\text{--}150\,mL$

  • Extra-Large Prostates: $150\,mL+$ (evaluated up to $242\,mL+$ in clinical studies)

  • Historical Compromise Paradigms:

  • Non-Resective / Minimally Invasive Surgical Technologies (MIST): Prioritize preservation of sexual function and urinary continence but are clinically limited to small-to-medium gland sizes ($30\text{--}80\,mL$).

  • Standard Resective Procedures (TURP & Photovaporization/PVP): Prioritize symptom relief in small-to-large glands ($30\text{--}150\,mL$) but exhibit higher rates of irreversible complications (e.g., ejaculatory dysfunction, incontinence).

  • Enucleation (HoLEP, LEP) & Simple Prostatectomy: Effective for large and extra-large glands ($80\text{--}150\,mL+$) for symptom relief, but require steep learning curves and carry increased perioperative morbidity.

  • The Aquablation Solution: Offers a single, standardized, robotic resective modality capable of treating prostates ranging from $20\,mL$ to $242\,mL+$ without compromising safety or efficacy outcomes.

Prostatic Vascular Anatomy and Hemostasis Fundamentals

• Prostatic Arterial Supply Tree:

  • Blood supply originates from the Internal Iliac Artery, giving rise to the Inferior Vesicle Artery.

  • The Inferior Vesicle Artery branches into the Prostatic Artery, which further divides into:

  • Urethral group of arteries: Supplies the inner periurethral gland and bladder neck.

  • Capsular group of arteries: Extends along the outer prostatic capsule.

  • Secondary vascular contributions derive from branches of the middle hemorrhoidal and pudendal arteries.

• Bladder Neck Vascular Vulnerabilities:

  • Major arterial networks concentrate directly at the bladder neck, specifically surrounding the anterior bladder neck and the posterior bladder wall.

  • Key target structures in this region include the median lobe and the left and right lateral lobes.

  • Conservative depth planning at the bladder neck reduces direct exposure and surgical disruption of these major blood vessels.

Clinical Evidence and Trial Outcomes

• WATER Trial (Double-Blind RCT vs. TURP; Prostates $30\text{--}80\,mL$):

  • 5-year follow-up results published by Gilling PJ et al. (Can J Urol, 2022) demonstrated durable efficacy and superior safety compared to Transurethral Resection of the Prostate (TURP).

  • Demonstrated a $51\%$ reduction in patients returning to BPH medications or requiring secondary surgical intervention compared to TURP at 5 years.

  • $96\%$ of patients remained free from secondary BPH surgical procedures at 5 years post-treatment.

  • Significantly improved patient symptom scores from "Severe" to "Mild" as measured by the International Prostate Symptom Score (IPSS).

  • $83\%$ of patients preserved normal ejaculatory function (Elterman et al., 2021 meta-analysis).

• WATER II Trial (Large Prostates $80\text{--}150\,mL$):

  • 5-year follow-up results published by Bhojani N et al. (J Urol, 2023) confirmed long-term durability and symptom relief in large glands, matching the efficacy observed in smaller prostates.

• Predictable Resection Times:

  • Trial data confirmed that robotic automation maintains consistent waterjet execution and resection timing regardless of total prostate volume or prior surgeon experience level.

Evolution of Focal Bladder Neck Cautery (FBNC)

• Comparative Transfusion Rate Reductions:

  • Pre-FBNC Standardization Period ($2017\text{--}2020$) ($0\%\text{--}11\%$ FBNC implementation):

  • WATER I (RCT vs. TURP): $0.9\%$ transfusion rate ($n=135$, prostate size $25\text{--}80\,mL$).

  • WATER II (Large Prostates): $5.9\%$ perioperative transfusion rate ($n=101$, prostate size $80\text{--}150\,mL$; $4\%$ occurring post-discharge within 30 days).

  • OPEN WATER (All-Comers): $2.7\%$ transfusion rate ($n=178$, prostate size $20\text{--}150\,mL$).

  • Post-FBNC Standardization Period ($2020\text{--}2024$) ($40\%\text{--}100\%$ FBNC implementation):

  • FBNC Technique Study (Elterman et al., 2021): Transfusion rate reduced to $0.8\%$ ($n=2{,}089$, prostate size $20\text{--}363\,mL$).

  • WATER III RCT vs. LEP (Ritter et al., 2025 EAU): $0\%$ transfusion rate ($n=186$, prostate size $80\text{--}180\,mL$).

  • Quintas et al. (Minerva Urol Nephrol, 2024; AB vs. HoLEP): $0\%$ transfusion rate ($n=150$, prostate size $50\text{--}150\,mL$).

  • Japan Post-Market Survey (Hinata et al., Int J Urol, 2024): $1.0\%$ transfusion rate ($n=103$, prostate size $33\text{--}242\,mL$).

  • FDA MAUDE & PROCEPT Database Analysis ($2019\text{--}2024$): $0.2\%$ transfusion rate ($n=70{,}270$, prostate size $20\text{--}1{,}189\,mL$).

• Outpatient / Same-Day Discharge Clinical Feasibility Data:

  • Academic Helfand Series (2021 White Paper): Achieved an $87\%$ same-day discharge rate; $0\%$ hospital readmissions, $0\%$ transfusions, and zero patients requiring home bladder irrigation.

  • Surgery Center Zorn Series (AUA 2024): Achieved a $98\%$ same-day discharge rate in an ambulatory surgery center setting; $0\%$ readmissions or transfusions requiring return to the operating room.

  • Community Ng Series (BJU Int, 2024): Achieved a $92.5\%$ same-day discharge rate; $100\%$ successful Trial Without Catheter (TWOC) on post-operative day 3 with zero significant complications or readmissions.

Multi-Dimensional Treatment Planning Protocols

• Transverse / Angle Planning Mechanics:

  • Mid-Prostate Angle Plan:

  1. Retract transrectal ultrasound (TRUS) probe to the widest cross-section of the mid-prostate.

  2. Place marker #2 at the maximum desired depth of waterjet penetration.

  3. Place markers #3 and #4 directly along the outer surgical capsule boundaries.

  • Median Lobe Angle Plan:

  1. Advance TRUS probe so the widest section of intravesical median lobe tissue is completely surrounded by intravesical bladder space.

  2. Ensure seminal vesicles and bladder neck boundaries are excluded from this specific transverse view.

  3. Plan an angle for intravesical tissue; this action creates a purple reference line indicating selected ablation depth in the longitudinal/sagittal planning mode.

  4. Increasing targeted depth increases waterjet ablation power; increasing angle expands lateral tissue resection.

• Sagittal / Contour Planning Mechanics:

  • Treatment Start Contour:

  • Place the treatment start marker at the proximal tissue edge at the targeted depth.

  • Use the purple reference line (derived from transverse angle planning) to confirm correct depth positioning.

  • Bladder Neck Contour:

  • Place marker #2 above bladder neck tissue to maintain a conservative margin, minimizing major vessel exposure while ensuring sufficient resection depth.

  • Place marker #4 at the purple reference line to match depth selected in transverse planning, preventing undertreatment.

  • Mid-Prostate Contour:

  • Align depth markers with the purple reference line generated during transverse planning.

  • Planning Above the Purple Line: Reduces the radius of the planned ablation angle (e.g., reducing contour depth by $3\,mm$ above the purple line contracts the overall transverse treatment area).

  • Planning Below the Purple Line: Increases the radius of the planned ablation angle (exceeding the purple depth marker is restricted in specific software versions).

  • Apex and Verumontanum Protection Zone (VPZ) Planning:

  • Identify the peripheral zone and urethral cliff to delineate the apical contour boundaries.

  • Verify that waterjet power remains adequate at the terminal resection zone.

  • Adjust VPZ length and depth based on verumontanum (veru) position and patient functional priorities.

• Anatomical Predictors of Ejaculatory Function Preservation (Nguyen D et al., 2021):

  • $5\,mm$ or Less Contour Depth Below Veru ($\le 5\,mm$): Sparing apical tissue within $5\,mm$ below the verumontanum preserves ejaculatory duct orifices, resulting in a lower risk of anejaculation. Recommended when preservation of sexual function is a clinical priority.

  • **Greater than $5\,mm$ Contour Depth Below Veru (> 5\,mm$)**: Planning apical contour depth deeper than 5\,mm below the verumontanum yields a **greater risk of anejaculation**. Used when maximal tissue debulking is prioritized over ejaculatory function preservation.\n* **Relationship Between Treatment Depth and Waterjet Power**:\n * A direct relationship exists between targeted treatment depth and delivered waterjet power level.\n * Soft tissue (prostatic adenoma) is removed across all three treatment zones.\n * The mechanical ability of the waterjet to remove, disrupt, or preserve structural collagen matrices varies predictably based on depth and power settings.\n\n# Surgical Execution and Focal Bladder Neck Cautery Workflow\n\n* **Plan for Success Checklist**:\n * Identify intravesical median lobe tissue and plan its angle in transverse mode to establish the purple reference line.\n * In sagittal mode, position marker **#2** above bladder neck tissue to protect primary blood vessels.\n * In sagittal mode, position marker **#4** directly on the purple reference line to avoid undertreatment.\n * Verify placement of the Treatment End marker to ensure complete waterjet tissue resection down to the apex.\n* **Step-by-Step Focal Bladder Neck Cautery (FBNC) Protocol**:\n 1. **Continuous Ultrasound Guidance**: Maintain continuous TRUS monitoring throughout FBNC execution to track positional location during clot evacuation and tissue resection. Reposition TRUS probe as necessary to relieve compression on the prostatic fossa caused by the resectoscope.\n 2. **Irrigation and Clearance**: Flush the bladder and prostatic fossa thoroughly with irrigation fluid to clear stagnant blood and blood clots.\n 3. **Bladder Neck Entry**: Direct the resectoscope scope to the bladder neck and establish an initial starting point to resect residual adenoma. If intraoperative visibility is obscured by active bleeding, inspect the 12 o'clock position first, then initiate tissue resection at either the 3 o'clock or 9 o'clock position.\n 4. **Systematic Depth Management**: Define a clear resection depth and execute systematic, circumferential resection within a unified anatomical plane (utilizing a 120^ atom$$ waterjet angle guide).

  1. Anterior and Median Lobe Inspection: Re-evaluate median lobe tissue and anterior tissue at the 12 o'clock position; perform targeted cauterization on all potential bleeding sites.

  2. Apical Inspection: Position the scope at the prostatic apex, turn off active fluid irrigation entirely, and perform a systematic visual inspection for residual arterial bleeding under normal baseline blood pressure.

• Optional Secondary Resectoscope Use:

  • Surgeons may utilize the resectoscope prior to standard post-operative workflow to clear remaining intravesical median lobe fragments or excise extra-planar tissue located outside the waterjet trajectory (e.g., anterior channel or far apical tissue).

• Catheter Placement and Continuous Bladder Irrigation (CBI):

  • Place a 3-way hematuria urinary catheter into the bladder under direct TRUS visualization.

  • Apply standard catheter traction according to institutional protocol.

  • Initiate Continuous Bladder Irrigation (CBI).

  • Track effluent color against the Stout et al. (Urology 2020) scale, striving to maintain Grade I color clarity (Scale ranges from Grade I [clear/pink] to Grade V [heavy blood/clots]).

System Platform Architecture and Complete Safety Profile

• Platform Features and Integrated Technology:

  • Robotic Resection: Automated, heat-free high-velocity waterjet execution following user-defined treatment boundaries.

  • Streamlined Tower Footprint: Integrated single-footprint system tower facilitating efficient operating room setup and room turnover.

  • FirstAssist AI™ Integration: Artificial intelligence software module designed to assist urologists in identifying prostatic anatomical landmarks on ultrasound and recommending optimized patient-specific treatment boundaries.

  • Advanced Image Guidance: Real-time simultaneous intraoperative transrectal ultrasound and cystoscopic visual streams.

• Critical Safety Warnings:

  • WARNING: Unaddressed vascular bleeding can lead to serious patient harm or life-threatening outcomes requiring acute clinical intervention.

• Common Transient Side Effects:

  • Mild dysuria or pain during micturition.

  • Pelvic discomfort.

  • Hematuria (blood in urine).

  • Transient urinary retention (inability to empty bladder).

  • Urinary urgency and frequency.

  • Lower urinary tract infection (UTI) or bladder infection.

• Perioperative Surgical Risks and Adverse Events:

  • Anesthesia-related complications.

  • Bladder or prostatic capsule perforation.

  • Bladder neck contracture.

  • Hematuria and severe hemorrhage.

  • Penile, pelvic, or ecchymotic bruising and pain.

  • Irritative lower urinary tract symptoms.

  • Surgical site infections and potential bloodborne pathogen transmission.

  • Transurethral Resection (TUR) Syndrome.

  • Intraoperative electric shock or thermal burns from secondary cautery devices.

  • Urethral mucosal trauma resulting in false passage creation or urethral strictures.

  • Rectal wall perforation or rectal incontinence.

  • Sexual dysfunction, including persistent erectile dysfunction and irreversible ejaculatory dysfunction.

  • Urinary incontinence or de novo overactive bladder.

  • Vascular embolism.

  • Persistent post-operative urinary retention.