Benign prostate enlargement
Aquablation aims to improve urinary flow by removing the prostate tissue causing obstruction.
Prostate care · Patient guide
Aquablation with the HYDROS robotic system: a day-case patient guide
A clear explanation of how waterjet treatment for an enlarged prostate works, what the surgeon controls, and when it may be possible to go home on the same day.
Imaging, planning and waterjet
The surgeon uses live views to plan treatment; the robotic system then follows the approved plan.
Same day for selected patients
Day-case discharge may be possible after safe recovery checks. An overnight stay is sometimes needed.
What problem does Aquablation treat?
Aquablation is a treatment for urinary symptoms caused by a non-cancerous enlarged prostate, also called benign prostatic hyperplasia or BPH. The prostate sits below the bladder and surrounds the urethra—the tube that carries urine out of the body. When the prostate enlarges, it can squeeze this tube and make it harder for the bladder to empty.
Symptoms can include a weak or interrupted stream, difficulty getting started, passing urine frequently or urgently, getting up several times at night, a feeling that the bladder has not emptied, or urinary retention.
These symptoms are not always caused by BPH, so assessment comes first. This may include a symptom score, urine test, PSA blood test where appropriate, urine-flow test, bladder scan and imaging or cystoscopy depending on your circumstances. Read more about benign prostate enlargement.
Important distinctionAquablation treats benign prostate enlargement. It is not a treatment for prostate cancer. A raised PSA or another cancer concern follows a separate diagnostic pathway.
What is different about the HYDROS system?
The HYDROS Robotic System is a newer platform from PROCEPT BioRobotics for delivering Aquablation therapy. It brings real-time ultrasound, direct camera views and computer-assisted treatment planning together in one system.
Real-time ultrasoundThe surgeon can see the whole prostate and its relationship to the bladder and urinary channel.
Digital cystoscopyA slim telescope provides a direct view through the urethra.
Computer-assisted planningFirstAssist AI can identify important landmarks and suggest a treatment outline.
Surgeon-controlled treatmentThe surgeon checks and adjusts the plan before the waterjet treatment is started.
The phrase “AI-powered” can sound as if a machine makes the decisions. It does not. The software supports image recognition and planning; the surgeon remains responsible for checking the anatomy, changing the suggested plan where needed, and starting or stopping treatment.
What “heat-free” meansThe waterjet removes prostate tissue without heat. Your surgeon may still use focused cautery afterwards to control bleeding. It is therefore more accurate to describe the tissue-removal step as heat-free than to say that no heat can be used anywhere during the operation.
See how the HYDROS system delivers Aquablation
This manufacturer animation explains the imaging, planning and waterjet stages. It is for general education; the exact procedure and equipment used are confirmed by your treating hospital.
What happens during the operation?
Anaesthetic and positioning
Aquablation is usually performed under a general or spinal anaesthetic. You lie on your back with your legs supported. Nothing is cut through the skin.
The prostate is mapped in real time
A slim telescope is passed through the urethra, and an ultrasound probe is placed in the rectum. Together, these views show the prostate, bladder neck and tissue causing the blockage.
Your surgeon plans the treatment
The surgeon marks the tissue to remove and structures to protect. On HYDROS, computer-assisted image recognition can suggest landmarks. The surgeon reviews and can alter every part of the plan.
The controlled waterjet removes obstructing tissue
The robotic system follows the approved plan and directs a high-velocity jet of sterile fluid at the obstructing tissue, creating a wider channel for urine.
Bleeding is checked and a catheter is placed
Loose tissue is cleared and the surgeon checks carefully for bleeding. Focused cautery may be used. A catheter is normally left in the bladder and irrigation may run through it for a few hours.
What does day-case Aquablation mean?
Day case means that you are admitted, have the operation and return home on the same calendar day. It does not necessarily mean going home without a catheter.
1 · Before surgeryTests, medicines and anaesthetic fitness are reviewed.
2 · AdmissionAn early operating time allows several hours for safe observation.
3 · RecoveryNurses monitor comfort, bleeding and catheter drainage.
4 · DischargeYou go home only when the agreed safety criteria are met.
5 · TWOCThe catheter is removed and bladder emptying is checked, often within a few days.
Checks before you go home
You should be medically stable, comfortable on suitable pain relief, able to eat and drink, and have acceptable urine drainage. You need clear catheter instructions, suitable support at home and a plan for contacting the team if a problem develops.
You may stay overnight if there is heavier bleeding, troublesome nausea, a medical or anaesthetic concern, a late finish, difficulty with catheter drainage, or if the team feels that further observation is safer. Needing an overnight stay does not mean the operation has failed.
Who may be suitable for same-day discharge?
The decision is personalised. Prostate size alone does not decide whether you can go home on the same day. The team may consider whether:
- your medical conditions are stable;
- blood-thinning medication has been managed appropriately;
- you have a responsible adult with you after discharge;
- you can return promptly if a problem develops;
- pain, sickness and bleeding are controlled; and
- you are comfortable looking after a temporary catheter, if one is needed.
What benefits can patients expect?
NICE guidance says transurethral waterjet ablation can be used for lower urinary tract symptoms caused by BPH because it works well and there are no serious concerns about its safety when usual clinical governance, consent and audit arrangements are in place.
In the WATER randomised trial, Aquablation produced lasting improvement in urinary symptoms and flow at five years, with less procedure-related ejaculatory dysfunction than TURP. In the WATER II study of larger prostates measuring 80–150 mL, symptom improvement remained substantial at five years and 96.3% of patients had not needed another BPH operation.
How to read the evidence fairly
These long-term studies evaluate Aquablation therapy as a procedure. They should not be interpreted as a head-to-head trial proving that the newer HYDROS platform gives better clinical outcomes than the earlier AquaBeam system.
Evidence for day-case Aquablation is encouraging but still developing. In one UK report involving 40 selected patients, 37 went home on the day of surgery and three stayed overnight. This was a small, single-centre experience, so it supports feasibility rather than guaranteeing same-day discharge for every patient or hospital.
What are the possible side effects and risks?
All prostate operations have risks. Your surgeon will explain how these apply to you. Possible issues after Aquablation include:
- blood in the urine or bleeding that needs longer irrigation, treatment or, rarely, transfusion;
- burning, urgency or frequent urination while the prostate heals;
- urinary infection;
- difficulty passing urine after catheter removal, sometimes requiring another catheter;
- temporary leakage of urine and, less commonly, persistent incontinence;
- scar tissue in the urethra or bladder neck;
- a change in ejaculation, including reduced or “dry” ejaculation;
- injury to the urinary tract or nearby structures; and
- risks related to anaesthesia, blood clots, heart or breathing problems.
Aquablation is associated with a better chance of preserving ejaculation than some traditional prostate operations, but preservation cannot be guaranteed. Erections are usually unaffected, although any procedure can have individual effects.
Recovery at home
It is common to notice some blood in the urine, mild stinging, frequency or urgency during the early recovery period. Symptoms can fluctuate as healing progresses.
- Follow the fluid and catheter instructions given by your team.
- Take prescribed medicines exactly as directed.
- Walk gently, but avoid heavy lifting and strenuous exercise until cleared.
- Do not drive while taking strong painkillers or until you can control the car comfortably.
- Attend the planned catheter-removal and follow-up appointments.
Many people with desk-based work need around one to two weeks away, while heavier work and vigorous exercise usually require longer. Your surgeon’s advice takes priority because recovery varies with prostate size, bleeding, general health and the amount of tissue treated. For more detail, see the Aquablation comparison and recovery guide.
When to seek urgent helpContact your clinical team or seek urgent medical help for an inability to pass urine or a catheter that stops draining; heavy or worsening bleeding; large clots; fever above 38°C, shaking or feeling seriously unwell; severe or increasing pain; chest pain, shortness of breath or a painful swollen leg; or persistent vomiting. Use NHS 111, your GP, A&E or emergency services according to severity.
Common questions about HYDROS and day-case Aquablation
Does the HYDROS robot perform the operation by itself?
No. The system supports imaging, planning and precise execution, but the surgeon checks the anatomy, defines or adjusts the treatment plan and remains in control throughout.
Is HYDROS the same as Aquablation?
Aquablation is the treatment. HYDROS is a newer robotic platform that can be used to deliver that treatment.
Can I definitely go home on the same day?
No. Day-case discharge is possible for selected patients who meet safety criteria after surgery. An overnight stay may be recommended if you need longer observation.
Will I go home with a catheter?
Many patients do. It is usually temporary and removed after a few days, but the exact plan depends on your operation and recovery.
Will ejaculation be preserved?
Aquablation has a lower rate of ejaculatory problems than TURP in clinical trials, but no technique can guarantee normal ejaculation for every patient.
Can Aquablation treat a large prostate?
Clinical studies include prostate sizes from 30 mL to 150 mL. Suitability still depends on prostate shape, symptoms, other health conditions and your treatment priorities.
Does Aquablation treat prostate cancer?
No. It treats urinary obstruction caused by benign prostate enlargement. If PSA, examination or imaging raises concern about cancer, that requires a separate diagnostic pathway.
Discussing Aquablation in Birmingham
A consultation with Mr Syed Ali Shahzad can help establish the cause of your urinary symptoms and compare Aquablation with medication, Rezum, UroLift, TURP, laser surgery and other appropriate options. If Aquablation is suitable, the hospital, robotic platform, catheter plan and whether day-case discharge is realistic will be confirmed for your individual procedure.
Last reviewed: 6 September 2026.
This page provides general information and does not replace advice from your own clinician.
Clinical and patient-information sources
- NICE HTG691: transurethral waterjet ablation for lower urinary tract symptoms caused by BPH
- British Association of Urological Surgeons: Aquablation patient leaflet
- PROCEPT BioRobotics: HYDROS Robotic System
- Five-year WATER randomised trial outcomes
- Five-year WATER II outcomes for 80–150 mL prostates
- Feasibility of Aquablation as day-case surgery
Aquablation, HYDROS and FirstAssist AI are trademarks of PROCEPT BioRobotics.