Percutaneous Nephrolithotomy

Introduction

If you have been told you have a large or complex kidney stone, your urologist may have suggested a procedure called percutaneous nephrolithotomy, usually shortened to PCNL. The name sounds intimidating, but the procedure has been refined over several decades and is now one of the standard ways to clear stones that are too big to pass on their own or to be broken up by less invasive methods.

This guide is written for people who already know they have a stone problem and are now planning the next step. It explains what PCNL is, why it is offered for certain stones, what other treatments may be considered, the different surgical approaches available today, how to prepare, what the surgery itself involves, what recovery looks like, the risks to be aware of, and what to think about for long-term kidney health. A separate section covers PCNL in children, since stone disease in young patients raises some different questions.

Stone treatment is highly individual. The size, shape, hardness, and location of the stone, the anatomy of your kidney, your overall health, and your previous treatments all influence which approach is suitable. The information below is to help you understand the conversation with your urologist — it does not replace it.

What Is Percutaneous Nephrolithotomy?

Percutaneous nephrolithotomy is a minimally invasive surgical procedure to remove kidney stones through a small opening in the skin of the back. The three parts of the word describe what happens:

• Percutaneous means “through the skin.”
• Nephro refers to the kidney.
• Lithotomy means “removal of a stone.”

The surgeon makes a small incision — usually about one centimetre — in the flank or upper back, then creates a narrow tunnel, called a tract, directly into the part of the kidney where the stone sits. A telescope-like instrument called a nephroscope is passed through this tract. The stone is broken into fragments using energy delivered through the scope (laser, ultrasonic, or pneumatic), and the pieces are removed.

PCNL was first performed in the late 1970s and has steadily replaced traditional open stone surgery for most large stones. Both the European Association of Urology (EAU) and the American Urological Association (AUA) guidelines describe PCNL as the standard surgical approach for kidney stones larger than two centimetres and for complex stones such as staghorn calculi.

Why Is PCNL Performed?

PCNL is offered when a kidney stone is too large, too hard, or too awkwardly placed to be treated effectively by simpler methods. Common reasons your urologist may recommend it include:

• Stones larger than two centimetres. Smaller stones can often be treated with shock waves or a scope passed up through the urinary tract, but those methods become less effective and slower as stone size increases.
• Staghorn stones. These are large branching stones that fill the inner collecting system of the kidney, often shaped a bit like a piece of coral or a stag’s antlers. They usually need to be removed surgically because of the risk of infection and kidney damage if left in place.
• Hard stones that resist shock wave treatment. Some stone compositions, such as calcium oxalate monohydrate, brushite, or cystine, are too hard for shock waves to break.
• Multiple stones in the same kidney. Removing several stones in one operation is often easier through a percutaneous tract than through repeated shock wave or ureteroscopic sessions.
• Stones in a lower-pole calyx with unfavourable anatomy. Fragments produced by shock waves may not drain well from the lower pole, and PCNL allows direct removal.
• Stones causing obstruction or infection. When a stone is blocking urine flow or is associated with recurrent infection, definitive removal is usually needed.
• Stones in a kidney with abnormal anatomy — such as a horseshoe kidney, a kidney that has dropped down (ptosis), or a kidney that has previously been operated on.

Who Is a Candidate?

Most adults with the indications above can be considered for PCNL, but the decision is individual. Your urologist will look at:

• Stone factors: size, number, location within the kidney, composition (if known), and density on CT imaging.
• Kidney anatomy: the position of the kidney, the shape of the collecting system, the relationship of the kidney to nearby organs such as the colon, lung, liver, and spleen.
• Your general health: heart and lung function, bleeding tendencies, diabetes control, body weight, and any medications (especially blood thinners).
• Urine status: active urinary infection must be treated before surgery to reduce the risk of sepsis.
• Previous treatments: earlier shock wave sessions, ureteroscopy, or open surgery in the same kidney can affect planning.

People who are not suitable for PCNL include those with untreated bleeding disorders, untreated urinary tract infection, and certain anatomical situations where the kidney cannot be safely reached through the back. Pregnancy is generally a contraindication; temporary measures such as a ureteric stent are usually used during pregnancy, and definitive stone treatment is delayed until after delivery.

Alternatives to PCNL

Several other treatments exist for kidney stones. Your urologist will weigh PCNL against these options based on the stone and your situation.

Watchful waiting and medical management

Small stones — typically those under five millimetres — may pass on their own with hydration, pain relief, and sometimes medication that relaxes the ureter (such as an alpha-blocker). This approach is not suitable for the large stones that PCNL is designed to treat, but it is the right choice for many smaller stones found incidentally.

Extracorporeal shock wave lithotripsy (ESWL)

ESWL uses focused shock waves delivered from outside the body to break stones into smaller fragments that can pass in the urine. It is non-invasive and usually done as a day case. It works best for stones under two centimetres, particularly those in the kidney or upper ureter, and for less dense stone compositions. It is less effective for very hard stones, lower-pole stones, and obese patients. Multiple sessions may be required, and residual fragments are more common than after PCNL.

Retrograde intrarenal surgery (RIRS) with flexible ureteroscopy

In RIRS, a thin flexible scope is passed up through the urethra, bladder, and ureter into the kidney. A laser fibre is used to break the stone into very small fragments or dust. There are no incisions. RIRS is generally favoured for stones up to about two centimetres and for situations where PCNL carries higher risk — for example, in patients on blood thinners, or with bleeding disorders, or with unfavourable anatomy for percutaneous access. For larger stones, more than one RIRS session may be needed to clear the stone burden.

Combined or staged procedures

For very large or complex stones, surgeons sometimes combine PCNL with RIRS in the same operation — an approach known as endoscopic combined intrarenal surgery (ECIRS) — or stage two procedures a few weeks apart. The aim is to clear the stone with the fewest tracts and the least risk.

Open or laparoscopic stone surgery

Traditional open stone surgery, in which the kidney is opened directly through a larger incision, is now rarely performed. Major guidelines reserve it for unusual situations — for example, very complex anatomy or a stone burden that cannot be cleared by other means. Laparoscopic and robotic stone surgery are also occasional options in specific cases.

Which alternative makes sense depends on stone size, hardness, location, your anatomy, and local expertise. EAU and AUA guidelines describe a stepwise framework: stones under two centimetres are usually treated first with ESWL or RIRS, while stones over two centimetres or staghorn stones are usually treated first with PCNL.

Surgical Approaches

PCNL itself has evolved into a family of related approaches. The main difference between them is the size of the tract created into the kidney. Smaller tracts generally cause less bleeding and pain but limit how big a stone fragment can be removed at a time, which can lengthen the operation. The choice depends on stone size, location, and surgeon experience.

Standard PCNL

Standard PCNL uses a tract of about 24 to 30 French (around 8 to 10 millimetres in diameter). The wider tract allows large stone fragments to be removed quickly and gives the surgeon good visibility. It is well suited to very large stones, staghorn stones, and complex stone burdens. Because the tract is larger, there is somewhat more bleeding risk than with the miniaturised versions, and recovery can be slightly longer.

Mini-PCNL

Mini-PCNL uses a smaller tract, typically in the range of 14 to 20 French. Studies suggest that bleeding rates and the need for blood transfusion are lower than with standard PCNL, with similar stone-free outcomes for moderate-sized stones. It is often chosen for stones in the one-to-three centimetre range and for selected larger stones.

Ultra-mini PCNL

Ultra-mini PCNL uses an even smaller tract (around 11 to 13 French). It is used for smaller stones that still need a percutaneous approach — for example, when RIRS has failed or is not suitable.

Micro-PCNL

Micro-PCNL uses the smallest tract of all, often around 4 to 5 French. It is a relatively new approach used in selected cases, especially in children or when minimising kidney trauma is a priority. It is not suitable for very large stones because fragments cannot be removed efficiently through such a small tract.

Tubeless and totally tubeless PCNL

Traditionally, a drainage tube (nephrostomy) is left in the kidney for one or two days after PCNL. In selected uncomplicated cases — particularly with mini-PCNL — surgeons may use a “tubeless” approach, leaving only a ureteric stent inside, or a “totally tubeless” approach with no drain or stent. These variations can shorten hospital stay and reduce post-operative discomfort. Whether they are appropriate depends on the operation and is decided at the end of surgery.

Preparing for PCNL

Preparation typically begins one to several weeks before surgery.

Tests and assessments

• Imaging: A recent CT scan (usually a non-contrast CT KUB) is the most accurate way to map the stone, the collecting system, and surrounding structures. Sometimes a CT with contrast or an additional ultrasound is added.
• Urine culture: A fresh urine sample is checked for infection. If bacteria are present, antibiotics are given before surgery, and treatment may be delayed until the urine is sterile.
• Blood tests: Full blood count, kidney function, clotting tests, and a blood group with cross-match in case transfusion is needed.
• Anaesthetic review: An anaesthetist will assess fitness for general anaesthesia, particularly important for older patients and those with heart, lung, or other chronic conditions.
• Other tests: ECG, chest X-ray, or echocardiogram may be done depending on age and medical history.

Medication adjustments

Blood-thinning medicines — including aspirin, clopidogrel, warfarin, and the newer direct oral anticoagulants — usually need to be stopped or switched several days before surgery. This is done in consultation with the prescribing doctor, since stopping these medications carries its own risks. Diabetic medications, blood pressure tablets, and herbal supplements are also reviewed.

The day before and the day of surgery

• You will usually be asked not to eat for six to eight hours and not to drink clear fluids for two hours before surgery.
• A preventive dose of antibiotics is given just before the operation.
• You will change into a surgical gown and have an intravenous (IV) line placed.
• The surgical site and the side of the kidney to be operated on are confirmed and marked.

What Happens During PCNL

PCNL is performed under general anaesthesia in an operating theatre equipped with X-ray (fluoroscopy) and often ultrasound guidance. The procedure typically takes between one and three hours, sometimes longer for very complex stones.

Step by step

1. Anaesthesia. You are put fully to sleep. A breathing tube is placed and your vital signs are monitored throughout.
2. Initial cystoscopy and ureteric catheter. Many surgeons begin by passing a small scope into the bladder and threading a thin catheter up the ureter to the kidney. This catheter allows dye or saline to be injected to outline the collecting system during the operation.
3. Positioning. You are turned into the prone position (face down) or, in some centres, the supine position (face up with the side raised). Both positions are well established; the choice depends on surgeon preference, anatomy, and stone location.
4. Puncture and tract creation. Using fluoroscopy and/or ultrasound, the surgeon passes a fine needle through the skin of the back into the chosen part of the kidney’s collecting system. A guidewire is threaded through the needle. The tract is then gradually widened using dilators to the planned final size, and a hollow sheath is left in place.
5. Nephroscopy and stone fragmentation. The nephroscope is passed through the sheath into the kidney. Stones are visualised and then broken up using a holmium laser, an ultrasonic probe, a pneumatic (lithoclast) probe, or a combination. Fragments are removed with graspers or suction.
6. Inspection. The surgeon inspects the collecting system to check for residual fragments. Sometimes a flexible scope is used to look into calyces that the rigid nephroscope cannot reach.
7. Drainage. Depending on the operation, a nephrostomy tube may be left through the tract, a ureteric stent may be placed from the kidney to the bladder, or both. In selected cases neither is used (totally tubeless PCNL).
8. Closure. The skin incision is small and is closed with a stitch or two, or with a dressing.

Recovery and Healing

In hospital

Most people stay in hospital for two to four days after standard PCNL. Mini-PCNL and tubeless approaches sometimes allow earlier discharge. During the hospital stay:

• Pain is usually moderate and is controlled with oral or intravenous painkillers.
• A urinary catheter is generally left in place for the first day.
• If a nephrostomy tube is in place, it drains urine and any small clots into a bag for one to two days; it is removed before discharge in most cases.
• It is normal for the urine to look pink or lightly bloodstained for several days. Heavy bleeding or passing large clots should be reported.
• You will be encouraged to walk on the same day or the day after surgery to reduce the risk of clots in the legs.
• Blood tests may be repeated to check for bleeding and kidney function.

At home in the first two weeks

• Most people feel tired for the first week and need short rests during the day.
• Mild flank discomfort and bruising around the incision are common.
• If a ureteric stent has been left in place, you may notice an urge to pass urine more often, some discomfort in the bladder or flank when urinating, and traces of blood in the urine. These symptoms usually settle once the stent is removed.
• Stent removal is typically done as a brief outpatient procedure after one to four weeks, depending on the operation.
• Drinking plenty of water — aiming for pale, clear urine — helps flush small fragments and reduces clotting.
• Heavy lifting, strenuous exercise, and contact sports are usually avoided for about four weeks.

Beyond two weeks

Most people are able to return to office work within one to two weeks. Physically demanding work and exercise are generally resumed at three to four weeks, once the surgeon confirms healing is on track. A follow-up scan, often a CT or ultrasound, is done a few weeks to a few months after surgery to confirm that the kidney is clear of stones and that no late complications have developed.

Signs to report

Contact your surgical team or seek urgent care if you develop:

• Heavy or fresh bleeding in the urine, or passage of large clots
• Fever above 38°C, shaking chills, or feeling generally unwell
• Severe pain not controlled by your prescribed painkillers
• Increasing redness, swelling, or discharge from the incision
• Inability to pass urine
• Vomiting that prevents you from keeping fluids down

Risks and Complications

PCNL is generally safe in experienced hands, but, like any surgery on the kidney, it carries risks. Understanding them helps you make an informed choice and recognise problems early.

Common and usually minor

• Blood in the urine for several days after surgery.
• Pain at the incision and in the flank, usually well controlled by painkillers.
• Stent-related symptoms — urinary urgency, frequency, mild flank discomfort with urination.
• Fever in the first 24–48 hours, which may be a normal post-operative reaction or an early sign of infection.

More serious but less common

• Bleeding requiring transfusion. The kidney is a richly vascular organ. Significant bleeding occurs in a small percentage of cases and may need a blood transfusion. Rarely, an interventional radiologist needs to block off a bleeding vessel using a procedure called embolisation.
• Infection and sepsis. Even with preventive antibiotics, infection can develop, especially if the stone harboured bacteria. Sepsis is uncommon but serious and is one of the main reasons that urine is checked carefully before surgery.
• Injury to nearby organs. The colon, pleura (lung lining), liver, and spleen are close to the kidney. Injury is uncommon but possible, more so with upper-pole punctures, which can cause a small collection of fluid or air around the lung (hydrothorax or pneumothorax).
• Urine leak. Leakage of urine from the tract or collecting system may need a stent or extended catheter drainage to settle.
• Residual stone fragments. Fragments may remain, particularly with very large or branched stones. A second-look procedure — PCNL, RIRS, or ESWL — is sometimes planned in advance.
• Need for a second procedure. Even when the operation is straightforward, planned staged procedures are common for staghorn stones.
• Anaesthesia-related risks, as with any general anaesthetic.
• Loss of kidney function. A small reduction in function of the operated kidney is possible. Severe loss of function is rare.

EAU and AUA guidelines, and large international audits such as the CROES PCNL Global Study, describe overall stone-free rates after PCNL as generally high, particularly with experienced operators and modern imaging, but vary with stone size, complexity, and the approach used. Your urologist can give you a realistic estimate based on your own scan.

Life After PCNL

Stone analysis and metabolic evaluation

Fragments removed during PCNL are usually sent for chemical analysis. Knowing the composition — calcium oxalate, calcium phosphate, uric acid, struvite, cystine, or a mixed type — helps guide prevention. People with recurrent stones, a first stone at a young age, or unusual stone types are often offered a more detailed metabolic workup, which includes blood tests and a 24-hour urine collection.

Preventing future stones

Kidney stones are recurrent for many people — without preventive measures, a meaningful proportion will form another stone within five to ten years. General measures supported by major urological societies include:

• Fluid intake sufficient to produce at least 2 to 2.5 litres of urine per day — water is the preferred drink for most stone types.
• Moderating salt in the diet, since high sodium intake increases urinary calcium.
• Moderate animal protein intake rather than very high-protein diets.
• Normal calcium intake from food (low calcium diets can actually worsen stone formation).
• Limiting very high-oxalate foods (such as spinach, beetroot, and large amounts of nuts) for people with calcium oxalate stones, while still maintaining a balanced diet.
• Weight management and treatment of conditions such as gout, diabetes, and hyperparathyroidism that contribute to stone formation.

For some patients, specific medications — such as thiazide diuretics for high urinary calcium, potassium citrate for low urinary citrate or uric acid stones, or allopurinol — are added based on the metabolic workup. These decisions are made by the urologist or a nephrologist.

Follow-up imaging

An imaging study is typically arranged a few weeks to a few months after surgery to confirm stone clearance and check the kidney. People with a history of multiple stones often have periodic ultrasound or low-dose CT scans for years after, to catch new stones while they are still small.

PCNL in Children

Children can develop kidney stones too, and PCNL is sometimes the appropriate treatment. Pediatric stones often have a stronger link to metabolic and genetic conditions, urinary tract anomalies, or recurrent infections, so the evaluation usually includes detailed metabolic testing in addition to imaging.

The principles of PCNL in children are the same as in adults, but there are important differences:

• Smaller equipment. Mini-PCNL, ultra-mini PCNL, and micro-PCNL are particularly useful in children, as smaller tracts reduce the proportion of kidney tissue affected.
• Radiation considerations. Pediatric urologists try to minimise X-ray use, often relying more on ultrasound guidance.
• Anaesthesia. General anaesthesia is given by a paediatric anaesthetist, and the surgery is performed in centres set up for children.
• Recovery. Children tend to recover quickly but need careful pain management and close monitoring.
• Lifelong prevention. Because childhood stones often signal an underlying tendency, long-term follow-up with both a urologist and, where relevant, a paediatric nephrologist is important to reduce future stone formation.

If your child has been diagnosed with a large or complex kidney stone, treatment is best discussed with a paediatric urology team experienced in stone surgery.

Frequently Asked Questions

How long does PCNL take?

The operation itself usually takes between one and three hours, depending on the size and complexity of the stone, the anatomy of the kidney, and the approach used. Very large staghorn stones can take longer.

Will I feel pain during the procedure?

No. PCNL is done under general anaesthesia, so you are fully asleep and feel nothing during the surgery. Some discomfort in the flank is common in the first few days afterwards and is managed with painkillers.

How long will I be in hospital?

Most people stay for two to four nights after standard PCNL. Mini-PCNL and tubeless variations may allow shorter stays. Your length of stay depends on the operation, recovery, and whether tubes or stents are removed before discharge.

When can I go back to work?

Office or desk work is usually possible within one to two weeks. Physically demanding work, heavy lifting, and strenuous exercise are typically avoided for around four weeks. Your surgeon will give specific advice based on your recovery.

Will I need a tube or stent after surgery?

Often, yes. A nephrostomy tube may stay in for one or two days. A ureteric stent — a thin tube between the kidney and bladder — is commonly left for one to four weeks and is removed in a brief outpatient procedure. Selected cases are tubeless or totally tubeless.

How successful is PCNL?

Stone-free rates after PCNL are generally high, particularly for stones treated by experienced surgeons with modern imaging and instruments. The exact figure depends on stone size, hardness, and complexity, and on whether residual fragments are counted as a treatment failure. Your urologist can give you an individualised estimate based on your scan.

Is PCNL better than RIRS or ESWL?

None of these is universally “better.” EAU and AUA guidelines describe PCNL as the standard approach for stones larger than two centimetres and for staghorn stones, RIRS as well suited to stones up to about two centimetres or where percutaneous access is risky, and ESWL as useful for smaller, less dense stones. The right choice depends on the specific stone and patient.

Will my kidney work normally afterwards?

For most people, kidney function is preserved or returns to baseline after PCNL. A small reduction in function of the operated kidney is possible, particularly with multiple tracts or complications. Treating an obstructing stone often protects the kidney from further damage.

Can my stones come back?

Yes. Kidney stone disease is recurrent for many people. Stone analysis, metabolic evaluation when indicated, and lifestyle measures such as good hydration and dietary changes substantially reduce the risk of new stones.

What should I look for when choosing a surgeon or centre?

For complex stone surgery, experience matters. It is reasonable to ask how often the surgeon performs PCNL, what approaches (standard, mini, micro) they use, what imaging and equipment are available, and how complications such as bleeding are managed. Centres that handle large stone volumes and have interventional radiology support on site are well placed to manage rare complications.

Conclusion

Percutaneous nephrolithotomy has changed the treatment of large and complex kidney stones. What once required a sizeable open operation can now usually be done through a small incision in the back, with shorter hospital stays, faster recovery, and high rates of stone clearance. A range of approaches — from standard PCNL to mini, ultra-mini, and micro-PCNL, with or without post-operative tubes — allows the surgery to be tailored to the stone and the patient.

If you are preparing for PCNL, the most useful conversations with your urologist will cover the specific features of your stone and kidney, the approach being planned, what the recovery is likely to look like for you, and how to reduce the risk of new stones in the future. Understanding the procedure in advance does not remove the anxiety that comes with surgery, but it does make the path ahead clearer.