Does Aquablation Remove the Entire Prostate?

Aquablation does not remove the entire prostate. It is designed to carve out obstructive tissue from within the gland while leaving the outer capsule, surrounding nerves, and key anatomical landmarks intact. The procedure uses a high-velocity saline stream guided by real-time ultrasound imaging, and the surgeon maps a resection contour that deliberately stops short of the prostate’s outer boundary. This makes Aquablation fundamentally different from a radical prostatectomy, which takes out the whole organ, and it helps explain both the procedure’s strengths and its trade-offs.

How the Water Jet Works

Aquablation uses a robotically controlled stream of normal saline fired at high pressure through a handheld device inserted into the urethra. The water jet selectively destroys soft glandular tissue, which makes up the bulk of the prostate’s interior, while largely sparing tougher collagen-based structures like blood vessels, the ejaculatory ducts, and the prostatic capsule.¹ Before the jet fires, the surgeon uses transrectal ultrasound to outline the zone of tissue to remove, adjusting depth, length, and angle. That surgical plan is then executed by the robotic arm in a matter of minutes. In a trial of men with prostates ranging from 80 to 150 cc, the actual resection time averaged just eight minutes, even though the overall operative time was about 37 minutes.²

The key distinction from older surgical techniques is the imaging step. With traditional transurethral resection, the surgeon visually chips away at tissue through a scope, making real-time judgments about how deep to go. With Aquablation, the contour is mapped on ultrasound before the water jet activates, so the boundaries are set in advance. This is also what allows a deliberate decision about what to leave behind.

How Much Tissue Actually Gets Removed

The amount of prostate tissue removed by Aquablation is substantially less than what more aggressive procedures take out. A comparative study measured prostate volume at 12 months and found that Aquablation reduced gland size by about 39%, leaving residual glands averaging 33 cc. By contrast, patients who had holmium laser enucleation (HoLEP) saw a roughly 80% reduction, with residual glands averaging just 15 cc.³ That is a striking difference. HoLEP essentially shells out the adenoma down to the surgical capsule, while Aquablation removes a targeted channel through the obstructive tissue.

The settings are often adjusted so that the resection does not reach the surgical capsule at all, meaning the peripheral zone, central zone, and anterior fibromuscular stroma remain largely untouched.⁴ The procedure opens a wider channel for urine to flow through, but it is not trying to remove every gram of enlarged tissue.

There is, however, an experimental variant worth mentioning. A separate technique called prostate cancer Aquablation (PCAq) has been described for treating prostate cancer rather than benign enlargement. In that context, researchers have reported removing more than 95% of prostate tissue while preserving the true capsule.⁵ Even in that aggressive application, the capsule stays. But PCAq is a distinct procedure from the standard BPH Aquablation most patients encounter, and the two should not be confused.

Why Leaving Tissue Behind Preserves Sexual Function

One of the main reasons Aquablation is designed as a partial resection is to protect ejaculatory function. The ejaculatory ducts run through the prostate and open near a small bump on the urethral floor called the verumontanum. When surgical planning spares this area, the ducts stay intact and semen can still travel forward during orgasm. The procedure’s software allows the surgeon to set a “verumontanum-sparing” boundary that keeps the water jet away from this zone.⁶

How well this works in practice depends on how carefully the boundary is drawn. A case-control study using ultrasound video recordings found that penetrating the ejaculatory ducts during resection dramatically raised the odds of losing antegrade ejaculation, and cutting deeper below the verumontanum also increased the risk in a dose-dependent way.⁷ In the landmark randomized WATER trial comparing Aquablation to traditional TURP, the difference was clear: about 10% of sexually active Aquablation patients lost ejaculation versus 36% of TURP patients.⁸ In the large-prostate WATER II trial, antegrade ejaculation was maintained in about 81% of sexually active men at one year.²

This trade-off is central to understanding Aquablation’s design philosophy. The procedure intentionally leaves more tissue than HoLEP or TURP to give the surgeon room to protect structures that matter for quality of life. If someone needed every last bit of tissue removed, they would likely be steered toward a different procedure.

Urinary Symptom Relief Despite Partial Removal

You might wonder whether leaving so much tissue behind compromises the results. On urinary symptoms, the evidence says no, at least through medium-term follow-up. A meta-analysis pooling individual patient data from multiple Aquablation studies found a consistent 16-point improvement in symptom scores at one year, with average peak urinary flow rates reaching about 20.5 mL per second. The improvement was remarkably consistent regardless of prostate anatomy or baseline severity.⁹

In the WATER II trial focusing on larger prostates (80 to 150 cc), three-year data showed that symptom scores had improved by about 16 points and peak flow had roughly doubled from baseline.¹⁰ These improvements held up well over time. At five years, the vast majority of patients in both the WATER and WATER II trials remained free of BPH medications and had not needed surgical retreatment.¹¹ Five-year data from the original WATER trial also showed that the risk of needing any secondary BPH therapy was about half that of the TURP group.¹²

So while Aquablation removes proportionally less tissue than HoLEP, the functional relief is robust. The water jet opens a wide enough channel that urine flows freely, and the tissue it leaves behind does not, for most patients, re-obstruct within the first several years.

What Happens to PSA Afterward

Because Aquablation leaves a significant amount of prostate tissue in place, your PSA level will not drop to zero the way it would after a radical prostatectomy. At two years in the WATER trial, PSA fell modestly in both the Aquablation and TURP groups, by roughly one point on average.¹³ Longer-term data from the WATER II trial showed that PSA dropped by about 50% relative to baseline over five years.¹⁴ In the large-prostate cohort, baseline PSA averaged 7.1 and fell to about 4.4 at one year.²

This matters for ongoing cancer screening. Because you still have prostate tissue producing PSA, your doctor can still use PSA trends to monitor for prostate cancer after Aquablation. With procedures that remove nearly all the adenoma, the post-surgical PSA baseline is so low that small rises can be harder to interpret. After Aquablation, the remaining tissue provides a more familiar surveillance landscape, though the post-procedure drop itself needs to be accounted for when setting your new baseline.

The Incidental Cancer Detection Gap

Every prostate surgery generates tissue specimens that pathologists examine under a microscope, and sometimes they find cancer that nobody knew was there. This is called incidental prostate cancer. Aquablation finds far less of it than HoLEP does, and the reason is straightforward: it removes less tissue, and the tissue it removes comes mostly from the transition zone rather than the peripheral zone where cancers most commonly grow.

A study comparing more than 1,200 patients found that incidental cancer was detected in about 6% of HoLEP patients but only 0.3% of Aquablation patients.¹⁵ Researchers noted that the histological material from Aquablation was also harder to evaluate because the water jet fragments tissue differently than a laser does.⁴

This does not mean Aquablation patients are less likely to have cancer. It means the procedure is less likely to stumble across it. If you have concerns about undetected prostate cancer, your urologist will likely recommend continuing with standard screening protocols after the procedure rather than relying on surgical pathology for reassurance.

Bleeding Risk and How Hemostasis Is Managed

One trade-off of the water jet approach is that it does not cauterize as it cuts. Unlike electrosurgical tools or lasers, the saline stream removes tissue without sealing blood vessels. After the resection is complete, the surgeon typically performs a separate hemostasis step using a standard cautery device at the bladder neck, followed by catheter traction to tamponade the resection bed.

Across 801 patients treated between 2014 and 2019, the overall transfusion rate was about 4%. However, the rate varied considerably depending on prostate size and the hemostasis technique used. When surgeons used standard catheter traction and performed cautery only as needed, transfusion rates ranged from roughly 1.4% to 2.5% across all prostate sizes. But when a catheter-tensioning device was used without cautery, transfusion risk climbed as high as 7.8% in the largest glands.¹⁶

Severe bleeding, while uncommon, can occur. One published case report described a patient who developed massive blood loss in the hours after the procedure, ultimately requiring 19 units of packed red blood cells and arterial embolization of both prostatic arteries to control the hemorrhage.¹⁷ Cases like this are rare but serve as a reminder that bleeding management is the most important safety consideration with this procedure, and that the hemostasis technique the surgeon uses matters.

The Surgeon Learning Curve

Because Aquablation is relatively new and relies on image-guided planning rather than freehand surgical skill, you might assume the learning curve is gentle. It is, but not uniformly. A multicenter study found that the two areas most affected by surgeon experience were blood loss and ejaculatory function preservation. Less experienced surgeons had higher hemoglobin drops and were less adept at planning the verumontanum-sparing zone. The researchers pointed to standardized hemostasis training and early mentorship on contour planning as the most effective ways to shorten the learning curve.¹⁸

For patients, the practical takeaway is that Aquablation outcomes are not entirely procedure-dependent. The surgeon’s familiarity with the planning software and their post-resection hemostasis routine meaningfully influence both safety and functional results. If you are considering the procedure, asking about your surgeon’s case volume and training history is reasonable.

Moving Into Outpatient Settings

Aquablation was initially performed exclusively in hospitals, in part because of concerns about post-operative bleeding requiring overnight observation. More recently, pilot work has explored performing the procedure in ambulatory surgery centers. An early U.S. feasibility study found that ambulatory Aquablation had higher contribution margins than TURP, GreenLight laser, or HoLEP, and saved roughly $1,800 per case compared to hospital-based Aquablation.¹⁹

Financial dynamics in other health systems reinforce this. An analysis within a single NHS trust found that Aquablation was the only BPH procedure to generate a net financial surplus, driven largely by its robotic-assisted classification attracting a higher reimbursement tariff. TURP and HoLEP both ran at median deficits in the same system.²⁰ These economic incentives are likely to accelerate adoption, which in turn raises the importance of surgeon training, since newer centers will be starting earlier on the learning curve. Whether outpatient Aquablation can maintain the same safety profile as hospital-based procedures, particularly for men with larger prostates or those on anticoagulants, is a question that larger studies will need to settle.