01Purpose and principlesWhat the treatment does and how it fits into care.
The three procedures solve a stone-clearance problem through different access routes. Shockwave lithotripsy delivers focused energy from outside the body to fragment a target; the resulting material must usually pass through the collecting system and ureter. Ureteroscopy passes a scope retrogradely through the urethra and bladder into the ureter or kidney, permitting direct fragmentation and extraction. Percutaneous nephrolithotomy enters the renal collecting system through a planned skin-to-kidney tract, allowing removal of a large renal stone burden.
Procedure selection starts with the site, size and clinical reason for treatment. The same fifteen-millimetre measurement produces different NICE recommendations for a renal and a ureteric stone. For renal 10–20 mm stones NICE considers URS or SWL, whereas for ureteric 10–20 mm stones it offers URS and considers SWL when local facilities can achieve clearance within four weeks. Large renal stones above 20 mm, including staghorn stones, are offered PCNL; URS is an alternative when PCNL is not an option. The table does not make every asymptomatic incidental stone require a procedure.
The EAU adds anatomical and material detail to the size framework. A lower-pole stone may fragment well yet leave material trapped by an unfavourable drainage angle or narrow infundibulum. Dense homogeneous stones above about 1000 Hounsfield units, brushite, calcium oxalate monohydrate and cystine are relatively resistant to SWL. Greater skin-to-stone distance, an untargetable stone and some skeletal configurations also reduce feasibility. EAU recommends PCNL or retrograde intrarenal surgery for lower-pole stones above 1 cm where SWL efficacy is limited; explain this nuance alongside the broader NICE renal 10–20 mm table.
Counselling should compare the chance of achieving clearance with one session, likelihood of further procedures, anaesthesia, recovery and particular harms. URS often offers earlier clearance and fewer retreatments than SWL for ureteric stones, at the cost of a more invasive procedure and greater procedural morbidity. PCNL is highly useful for large renal burdens, but bleeding and tract-related injury matter. Published clearance percentages depend on stone burden, definitions, imaging and operator context; a universal success percentage is not an honest substitute for an individual discussion.
Key points
- Apply separate NICE tables for renal and ureteric stones: adult renal stones above 20 mm, including staghorn stones, are offered PCNL; ureteric stones 10–20 mm are offered ureteroscopy.
- For adult renal stones below 10 mm, NICE offers SWL; for renal 10–20 mm, consider URS or SWL. For ureteric stones below 10 mm, offer SWL with specified reasons to consider URS, including inability to achieve clearance within four weeks.
- SWL fragments externally and often needs subsequent fragment passage or retreatment; URS provides endoscopic access through the urinary tract; PCNL creates a percutaneous tract for larger renal burdens, with a greater bleeding and access-injury burden.
- Lower-pole anatomy, stone hardness and density, targeting, body habitus and antithrombotic requirements can change the preferred option within a size group. A high chance of fragmentation is not the same as a high chance of fragment clearance.
- Treat urinary infection before definitive stone removal. Infected obstruction needs urgent drainage and infection control first; give procedure-specific prophylaxis according to culture and local policy rather than a universal prolonged course.
- Do not routinely pre-stent adults for SWL or leave a stent after an uncomplicated adult URS for a ureteric stone below 20 mm. When a stent or nephrostomy is needed, give it a documented indication and a removal or exchange plan.
02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.
Establish whether treatment addresses persistent symptoms, obstruction, infection-related stone burden, growth or another agreed indication. Clarify whether the immediate objective is emergency drainage or definitive clearance. A patient recovering from infected obstruction may need both, in separate episodes.
Check target visibility, stone density and likely composition, lower-pole anatomy, body habitus and any obstruction distal to the stone. Pregnancy, uncontrolled UTI, uncorrected bleeding disorder and an arterial aneurysm near the stone are important contraindications. Distal obstruction prevents a safe assumption that fragments will drain.
URS commonly requires general anaesthesia and can be limited by difficult ureteric access; failed access may be managed with a temporary stent and a staged procedure. PCNL requires a safe planned tract avoiding adjacent organs. A smaller tract can reduce blood loss in selected settings but does not eliminate bleeding or sepsis risk. Untreated UTI, tumour in the proposed access tract and a potential malignant kidney tumour are PCNL contraindications. EAU also lists pregnancy as a contraindication, with a qualified specialist exception: percutaneous stone removal is exceptional and should be considered individually only in experienced centres; this does not make it a routine alternative to pregnancy-contraindicated SWL.
SWL, nephrostomy and PCNL carry a higher bleeding-risk classification than URS in EAU guidance. If stone removal is essential and antithrombotic treatment cannot be interrupted, retrograde URS can be the preferred intervention. Interruption, continuation or bridging decisions need the indication and responsible prescriber; routine bridging is not an assumption for every anticoagulant.
03Assessment before treatmentTests and checks that guide safe selection.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
CT and image review for planningFirst step - Why
- Map size, location, density, stone burden and the proposed access route.
- Interpretation and limitations
- For PCNL, review cross-sectional anatomy for bowel, pleura and solid organs near a potential tract. For SWL, assess visibility, skin-to-stone distance and density; for URS, consider collecting-system and ureteric anatomy. Contrast imaging may be needed when collecting-system anatomy requires clarification, rather than used for every stone by default.
- 02
Urine testing and culture - Why
- Detect infection that changes timing and prophylaxis.
- Interpretation and limitations
- Obtain the indicated urine assessment before intervention and treat UTI before stone removal. Infected obstruction requires prior drainage and infection control. A sterile bladder culture does not guarantee a sterile renal stone; renal-pelvis urine or stone culture at PCNL can better inform postoperative infection management.
- 03
Blood count, renal function and haemostasis - Why
- Identify modifiable procedural risk and establish a recovery baseline.
- Interpretation and limitations
- Assess renal reserve and relevant coagulation, antithrombotic exposure and haemoglobin before a bleeding-risk procedure. Interpret results with the medication history and proposed access, rather than considering a normal INR sufficient to exclude every antithrombotic effect.
- 04
Post-treatment imaging - Why
- Determine whether clinically important residual stone or obstruction remains.
- Interpretation and limitations
- Choose ultrasound and/or plain imaging according to the target and question, using CT for symptoms or preoperative planning when needed. Residual fragments are not necessarily harmless: EAU recommends offering further treatment for fragments above 4 mm, with close surveillance when observation is selected. Agree the imaging plan from risk and the operation performed.
04Treatment approachPreparation, options, escalation and aftercare.
01Worked caseClear a large renal burden with a tracked drainFirst stepA forty seven year old woman has recurrent pain and a twenty four-millimetre renal-pelvis stone, with no current infection.+
- 1AlternativeThe team reviews CT, renal function, haemoglobin, urine culture and antithrombotic exposure. CT shows a feasible percutaneous route without interposed bowel, and the urine culture is negative. She is offered PCNL under the NICE greater-than 20 mm renal-stone recommendation, with discussion of bleeding, infection, organ injury, a possible second procedure and the alternative if PCNL becomes unsuitable.
- 2She chooses PCNL. Procedure-specific antibiotic prophylaxis is given under the hospital culture-based policy, and the surgeon fragments and removes the stone through the planned tract. Renal-pelvis urine and stone material are collected. A temporary nephrostomy is retained because the operative assessment favours drainage and observation of bleeding; its presence is an individual decision, not a requirement for every uncomplicated PCNL.
- 3Postoperatively she remains afebrile, drainage becomes clear and haemoglobin remains clinically stable. Assessment confirms satisfactory drainage without an ongoing need for the tube, which is removed by the procedural team before discharge. Stone analysis identifies calcium oxalate, and the discharge letter records that no internal stent was left.
- 4At the arranged review, ultrasound shows no collecting-system dilation and plain imaging appropriate to this radiopaque stone shows no residual target. Renal function is unchanged from baseline. The team documents the observed clearance assessment and completed tube removal, then agrees a prevention and surveillance plan appropriate to her recurrence risk rather than repeatedly scanning without a defined question.
02Choose between SWL and URSUse the correct ureteric size table and feasibilityA stable adult has a ureteric stone for which active treatment has been agreed.+
- 1For a ureteric stone below 10 mm, NICE offers SWL and considers URS if clearance cannot be achieved within four weeks with SWL, the stone is not targetable, SWL is contraindicated or a previous SWL course has failed. For 10–20 mm ureteric stones, offer URS; SWL remains a considered option if local provision can achieve clearance within four weeks.
- 2Explain that SWL involves targeting and subsequent passage of fragments, potentially with further sessions and colic, whereas URS involves endoscopic access, possible laser fragmentation and extraction. Discuss ureteric trauma, infection, anaesthesia and possible temporary stenting as well as the relative likelihood of a single-procedure result.
- 3Choose the option that is clinically feasible and acceptable to the patient. For an impacted proximal stone when URS has failed, percutaneous treatment may enter the discussion. Record the reason for departing from the usual first offer rather than transposing the renal-stone table onto the ureter.
03Prepare and finish safelyLink infection prevention and temporary devices to the actual operationA patient proceeds to planned SWL, URS or PCNL after shared decision-making.+
- 1Check that infection has been assessed and treated, antithrombotic management agreed and the correct stone and side confirmed. EAU does not recommend routine antibiotic prophylaxis for SWL with sterile urine; bacteriuria or an infected stone changes that decision. URS and PCNL prophylaxis follows procedure, culture and infection-risk evidence, not an identical prolonged schedule for all three methods.
- 2Avoid routine adult pre-stenting solely for SWL. After uncomplicated URS with complete clearance, a stent is often unnecessary; injury, perforation, residual fragments, bleeding, infection, pregnancy or doubt about drainage can justify one. PCNL may be tubeless in selected uncomplicated cases, but anticipated further access, bleeding, extravasation or drainage concerns can justify a nephrostomy or internal stent.
- 3Explain expected symptoms and the signs requiring urgent reassessment, including fever, worsening flank pain, inability to pass urine, heavy bleeding or device displacement. Arrange a result review, stone analysis and a specific owner and date for every temporary device. Verify the endpoint at follow-up rather than assuming the operative intention was achieved.
05Complications, monitoring and follow-upAdverse effects, response and longer-term review.
- After SWL, assess persistent pain, fever and obstruction from fragments, including a column of ureteric fragments; deterioration requires a new drainage and infection decision.
- After URS, check sepsis physiology, renal drainage and symptoms that could indicate ureteric injury or an obstructed stent. New fever is not adequately explained by expected stent discomfort.
- After PCNL, monitor haemodynamics, haemoglobin when indicated, urine drainage and signs of infection or injury involving adjacent structures; respond to the specific suspected complication.
- At review, reconcile imaging findings, stone composition, kidney recovery, further treatment needs and device status. Choose subsequent surveillance according to residual burden and metabolic risk.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
Fragmentation and clearance differ
SWL can break a stone effectively while an unfavourable lower-pole drainage path retains fragments. Anatomical reasoning therefore adds useful information beyond hardness and diameter when comparing procedures.
An internal drain is still a device
Stents can cause urinary frequency, discomfort and haematuria, but serious symptoms require assessment. Patient information should state a removal or exchange plan and contact route so an internal device is not forgotten simply because no external bag is visible.
Stone cultures can explain postoperative sepsis
A patient may develop fever after PCNL despite a negative preoperative bladder culture. A renal-pelvis sample or stone culture can identify an organism within the treated system and help target treatment if infection develops.
Residual fragments deserve a decision
EAU follow-up evidence shows particularly poor spontaneous clearance for fragments above 4 mm, supporting an offer of further treatment. Smaller fragments also have progression and intervention risks, so surveillance should reflect the individual stone and recurrence profile.
07Common pitfallsFrequent interpretation and management errors.
- 01
Using the renal 10–20 mm URS-or-SWL options as the primary recommendation for a ureteric stone of the same size misapplies the NICE table.
- 02
Assuming all dense or lower-pole stones will clear after successful SWL fragmentation ignores material resistance and fragment drainage.
- 03
Proceeding with definitive manipulation through untreated infection can expose the patient to sepsis; infected obstruction first requires drainage and control.
- 04
Leaving every patient with the same stent duration or postoperative antibiotic course ignores the reason for the device and the procedure-specific infection assessment.