Mini Percutaneous Nephrolithotomy (mini PCNL)

Written and Medically Reviewed by Mr Ivo Dukic, Consultant Urologist | Last updated: 13/03/2026

What is the difference between PCNL and Mini PCNL?

Traditional PCNL (percutaneous nephrolithotomy) involves making a passage from the skin into the kidney to break up and remove stones. It has been around for decades, but the instruments are comparatively large: standard PCNL uses access sheaths of 24–30 French (Fr) in diameter (8-10 mm), whereas mini PCNL uses sheaths of 14–20 Fr in diameter (4.7- 6.7 mm) (1). Imagine the difference between drilling a hole into the kidney with a pencil-sized tool (mini PCNL) versus one the width of your thumb (standard PCNL). The smaller tract means:

- Less trauma and damage to the kidney
- Less bleeding and a significantly lower chance of requiring a blood transfusion (1,2)
- Shorter hospital stay and quicker recovery (1,2)

Studies confirm that stone clearance rates are equivalent between mini and standard PCNL for most stones (1,2,3). Mini PCNL does, on average, take around 8 minutes longer to perform than standard PCNL — a small trade-off for its safety benefits (1).

So, instead of dreading days in hospital, many of our patients are now home within 24–48 hours — and some even the same day.

It is less invasive, more precise, and — thanks to a few innovations like the use of thulium laser to break up stones and suction sheaths — it is now better than ever, with most of our patients with large stones having mini PCNL procedures rather than standard PCNL procedures.

Laser kidney stone surgery in Birmingham

For the last two decades, stones were broken into larger fragments with a holmium laser. This approach often produced larger fragments of stone that required active retrieval.

The new thulium fibre laser (TFL) "dusts" stones into fine powder that can be washed away or sucked out of the kidney, instead of creating larger, sharp fragments. It also produces less stone movement during treatment compared to the holmium laser (4,5). A prospective randomised trial found that TFL achieved stone-free rates of 92% compared with 67% for holmium, with a shorter operative time (49 vs 57 minutes) and less intraoperative bleeding (4). It should be noted that the evidence base for TFL is still maturing, and some trials — particularly those comparing modern high-powered holmium lasers — have found comparable stone-free rates between the two technologies (5,6). The advantages of TFL appear most pronounced for renal stones specifically.

For patients, this means fewer residual fragments, fewer repeat procedures, and shorter surgery times.

Suction Sheaths: A Built-In Vacuum Cleaner

Picture yourself drilling into a wall: dust flies everywhere, and you need to stop, clean up, and carry on. That used to be how stone surgery worked too — breaking stones up, then pausing to retrieve the pieces.

Suction-assisted sheaths have changed that. They allow us to break the stone and remove the debris at the same time. It is like having a tiny vacuum cleaner inside the kidney. A recent meta-analysis confirmed that suction-assisted sheaths in mini PCNL are associated with improved stone-free rates, shorter operative times, reduced pressure inside the kidney, and lower rates of postoperative fever and the need for blood transfusion (7,8).

The benefits are considerable:

- The kidney stays cleaner during surgery
- The pressure inside the kidney is lower, which reduces the risk of infection
- The whole process is quicker and smoother

Combined with the thulium laser, suction sheaths have made mini PCNL safer and more effective than ever before.

Here is the revised complications section only, expanded with the full BAUS complication list and incidence data, ready to drop into the document. The rest of the text remains unchanged.

Risks and Complications of mini PCNL

All surgery carries some risk, and mini PCNL is no exception. A systematic review reported an overall PCNL complication rate of approximately 8.5%, with minor complications in up to 25% of patients and major complications in 2–17.5% (1). The BAUS patient information leaflet (March 2025) lists the following recognised risks (2):

Common (between 1 in 2 and 1 in 10 patients)

- Urinary infection requiring antibiotic treatment. Bacteria present in the urinary tract can cause a postoperative infection. We give antibiotics before and during surgery to minimise this risk.

- Need for more than one puncture to clear your stones. Depending on the size and location of the stones, more than one channel into the kidney may be needed to achieve full clearance.

Uncommon (between 1 in 5 and 1 in 100 patients)

- Residual stone fragments requiring further treatment (approximately 1 in 5 to 1 in 20 patients). Even with modern technology, small fragments can occasionally remain. Our follow-up CT scan at 2–3 months is specifically designed to detect these. If fragments are present, further treatment — such as a repeat procedure or shockwave lithotripsy — may be needed. Fragments larger than 5mm are more likely to cause symptoms and require intervention (3).

- Sepsis (serious infection) requiring unexpected intensive care admission (between 1 in 10 and 1 in 100 patients). This is the most serious infectious complication of PCNL and a leading cause of perioperative morbidity. It occurs when bacteria enter the bloodstream during surgery. We use suction sheaths and low intrarenal pressure specifically to reduce this risk (4,5), as well as careful antibiotic protocols. If urosepsis occurs, it may require treatment in an intensive care unit.

- Moderately severe bleeding requiring embolisation (between 1 in 50 and 1 in 100 patients). Occasionally, significant bleeding from the kidney cannot be controlled conservatively. In these cases, interventional radiology can seal the bleeding vessel without open surgery — a technique called embolisation.

- Failure to obtain satisfactory access, requiring further surgery or an alternative treatment (between 1 in 50 and 1 in 100 patients). In a small number of cases, gaining safe access to the kidney is not possible, and the procedure may need to be abandoned or rescheduled.

- Infection at the puncture wound in the back (approximately 1 in 100 patients).

- Accidental injury to nearby organs — such as the liver, spleen, lung, or large bowel — (approximately 1 in 100 patients). The kidney sits close to other structures, and very rarely these can be grazed during access. Lung or pleural injury (causing a small collection of fluid in the chest, called a hydrothorax) occurs in approximately 1.5% of cases overall, most commonly when an upper pole access is used; this is usually managed conservatively with prolonged drainage (1,6). Bowel injury is very rare and is more likely in patients with abnormal anatomy (6).

- Anaesthetic or cardiovascular problems — including chest infection, blood clot (pulmonary embolus or DVT), stroke, heart attack, or, very rarely, death — (between 1 in 50 and 1 in 250 patients, depending on your overall health; your anaesthetist will estimate your personal risk before surgery) (2).

Longer-term considerations

- Stone recurrence. Approximately 50% of patients will form another stone within 10 years (7). This is why we arrange metabolic testing and give dietary advice after surgery.

- Ureteric or kidney scarring. Rarely, the access channel can cause scarring inside the kidney (infundibular stricture), which has been reported in around 2% of cases after standard PCNL (8). This risk is one of the reasons we prefer mini PCNL, which causes less tissue trauma.

- Need for blood transfusion. Significant blood loss requiring a blood transfusion is uncommon but possible. A large UK study reported a transfusion rate of 3.8% for standard PCNL (9); mini PCNL is associated with meaningfully less blood loss (10,11). Our rate of blood transfusion is around 0.5%.

- Hospital-acquired infection (MRSA or Clostridium difficile): your risk of acquiring a hospital infection during your stay is between 4% and 6% (2).

These complications are uncommon, and our use of mini PCNL, suction technology, and careful antibiotic protocols is specifically designed to minimise them. Please do not hesitate to ask your surgeon or specialist nurse if you have questions about any of these risks before your procedure.

The Stent: A Little Helper After Surgery

Almost everyone who has mini PCNL goes home with a ureteric stent. Think of this as a temporary internal drain: a soft tube that sits inside the ureter (the tube from the kidney to the bladder).

Why bother with a stent? After surgery, the ureter can swell a little. The stent keeps urine flowing freely, prevents blockages, and gives the kidney time to heal without pressure building up.

At our hospitals, we nearly always use stents on strings. This simply means a fine thread is attached to the stent and left coming out through the urethra (the tube you pass urine through). After 3–5 days, the stent can be removed quickly, without an anaesthetic.

Some patients do notice the stent. It can cause a bit of bladder irritation or the feeling of needing to pass urine more often. You may also notice the string when you go to the toilet. These effects are temporary, and the string allows easy removal of the ureteric stent.

Private mini PCNL in Birmingham:
Our Way of Doing Things

Every centre does things slightly differently, but here’s how we look after our patients:

• Before surgery: We ensure everyone has had a CT scan so we know exactly what we’re dealing with (the size, location and number of stones)

• During surgery: We use a mini tract, the thulium laser to dust the stone, and suction to clear it. A stent is placed before finishing. Most patients will not have any other tubes. Some may have a catheter or a tube in the back (nephrostomy). This is rare.

• After surgery, most people stay 1–2 nights. A select few go home the same day.

• Aftercare: The stent is removed after 3–5 days. Then, 2–3 months later, another CT scan checks that the stone is truly gone and whether any fragments remain.

When would you do a standard PCNL rather than a mini PCNL?

For very large or complex stones — usually partial or complete staghorn stones (stones that branch through multiple parts of the kidney) — standard PCNL still has a role. For most patients, however, mini PCNL is a safer option offering a similar degree of stone clearance (1,2,3). We often combine mini PCNL and standard PCNL in the supine position (lying on your back) with a flexible camera passed into the kidney through the urinary passage (urethra), to gain access to kidney stones from two different angles. This allows us to see stones in difficult-to-reach pockets (calyces) inside the kidney and improve the overall stone clearance rate.

The patient journey at our Birmingham sites

Here’s the journey in simple terms for most patients:

1. You come in for surgery and go to sleep with a general anaesthetic.

2. We make a pencil-sized channel into your kidney.

3. The stone is dusted into powder with the thulium laser while suction clears it away.

4. A stent is placed to protect the kidney.

5. You wake up, usually spend one night in the hospital, and go home with the stent.

6. The stent is removed 3–5 days later, using the attached string in an outpatient clinic.

7. A CT scan 2–3 months later confirms you are stone-free.

Simple, safe, and effective.

Frequently Asked Questions

Will I be in pain afterwards?
Most people describe mild discomfort in the side or back for a few days. It is usually well controlled with pain tablets.

What does the stent feel like?
Most patients notice a feeling of needing to pass urine more often and a dull ache. The string may feel unusual but is rarely painful.

How is the stent removed?
If it is on a string, we simply pull it out after 3–5 days. It is over in seconds and does not need another operation.

When can I go back to work?
Most people return to light duties within a week. If your job involves physical activity, allow a little longer.

Can the stones come back?
Yes, unfortunately. Some people are prone to forming stones. For patients who form stones repeatedly, European and UK guidelines recommend blood and urine tests — including a 24-hour urine collection — to look for underlying metabolic causes (10,11). We advise on diet and hydration to lower your risk, and the BAUS Dietary Advice for Stone Formers leaflet is a helpful resource (12).

Private mini PCNL in Birmingham

Kidney stones are painful, but the surgery to remove them doesn’t have to be. With mini PCNL, the thulium laser, and suction technology, we can now clear stones in a way that’s safer and leads to faster recovery.

At our hospitals, we’ve made these advances standard and mini PCNL is the default starting point for most large kidney stone surgeries (usually more than 15 mm stones). With careful imaging, short-term stents, and close follow-up, our goal is simple: to get you stone-free with as little disruption to your life as possible and with the lowest possible risks and potential complications.

If you’re facing kidney stone surgery, mini PCNL may be the one that gets you back to normal life fastest.

Further links

Information leaflet from the British Association of Urological Surgeons on PCNL

Animated video from the European Association of Urology (below)

Mr Ivo Dukic is one of the UK's premier PCNL surgeons and top kidney stone specialists, offering world-class urological care in Birmingham. As a distinguished Consultant Urologist with extensive expertise in high-volume kidney stone procedures, Mr Dukic is recognised as the leading PCNL expert in the West Midlands region.

Specialising in advanced Percutaneous Nephrolithotomy (PCNL) techniques, Mr Dukic delivers cutting-edge minimally invasive kidney stone treatments, including:

• Vacuum-assisted access sheath Mini-PCNL procedures for optimal patient outcomes

• Ultra-mini PCNL for reduced recovery times

• Advanced endoscopic kidney stone removal using ureteral vacuum-assisted access sheaths

• Complex renal stone surgery

All our PCNL surgery is carried out in the supine position (lying on your back) which allows us to perform complex surgery with multiple cameras in the kidney (endoscopic combined intrarenal surgery (ECIRS). This is done to try and maximise stone clearance in complicated stones whilst minimising potential complications.

His practice represents the gold standard in modern kidney stone surgery, combining years of specialist experience with the latest surgical innovations to provide patients across the UK and internationally with exceptional urological care and superior treatment outcomes.

You can schedule an appointment with him for expert, bespoke advice through his Top Doctors profile or book an appointment through Harborne Hospital, HCA Healthcare, the Priory Hospital, Edgbaston, Circle Health Group or Droitwich Spa, Circle Health.

References

1. Haghighi R, et al. Randomized control trial to compare mini-PCNL vs standard percutaneous nephrolithotomy for renal stones. PubMed Central. 2024. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC11670655/

2. He Z, et al. Comparison of mini percutaneous nephrolithotomy and standard percutaneous nephrolithotomy: a systematic review and meta-analysis. PubMed Central. 2022. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC9306366/

3. Xiao L, et al. A systematic review and meta-analysis of minimally invasive vs standard percutaneous nephrolithotomy. PubMed Central. 2021. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC7818531/

4. Ulvik O, et al. Thulium fibre laser versus holmium:YAG for ureteroscopic lithotripsy: outcomes from a prospective randomised clinical trial. Eur Urol. 2022;82(1):1–8. doi:10.1016/j.eururo.2022.02.026

5. Haas CR, et al. Pulse-modulated holmium:YAG laser vs the thulium fiber laser for renal and ureteral stones: a single-center prospective randomized clinical trial. J Urol. 2023. Available from: https://urology.wisc.edu/wp-content/uploads/2023/01/JU.YAG-vs-Thulium-for-renal-and-ureteral-stones.pdf

6. Taratkin M, et al. Thulium fiber laser vs Ho:YAG in retrograde intrarenal surgery: a prospective randomized study. PubMed Central. 2023. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC10693522/

7. Zhao Z, et al. Effectiveness and safety of suction-assisted versus traditional mini percutaneous nephrolithotomy: a meta-analysis. PubMed Central. 2025. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC12837080/

8. BJU International. Suction in mini-percutaneous nephrolithotomy: a meta-analysis. BJUI. 2025. doi:10.1111/bju.16891

9. Keoghane S, et al. Blood transfusion, embolisation and nephrectomy after percutaneous nephrolithotomy (PCNL). BJU Int. 2013;111(4):628–32. doi:10.1111/j.1464-410X.2012.11394.x

10. Skolarikos A, et al. Metabolic evaluation and recurrence prevention for urinary stone patients: EAU guidelines. Eur Urol. 2015;67(4):750–63. doi:10.1016/j.eururo.2014.10.029

11. National Institute for Health and Care Excellence. Renal and ureteric stones: assessment and management. NICE Guideline NG118. London: NICE; 2019. Available from: https://www.nice.org.uk/guidance/ng118

12. British Association of Urological Surgeons. Kidney stones — patient information. Available from: https://www.baus.org.uk/patients/conditions/6/kidney_stones/

Have any questions?

If you have any questions or wish to make an appointment please get in contact.