Committee I

Committee X

Urinary Tract Lithiasis

Prof. Omar A. Razak, Professor of Urology. Cairo University

Prof. Ehab Refaat, Professor of Urology. Minia University

Prof. Khaled Mursi, Professor of Urology. Cairo University

Contents
X.1 List of Abbreviations
  • IVU - Intravenous Urography
  • NSAID - Non-Steroidal Anti-Inflammatory Drug
  • PDE-5 - Phosphodiesterase type 5
  • URS - Ureteroscopy
  • RIRS - Retrograde and Antegrade,
  • URS - Ureteroscopy
  • ACOG - American College of Obstetrics and Gynecology
  • IVU - Intravenous Urography
  • RTA - Renal tubular acidosis
  • ALARA - As Low As Reasonably Achievable
  • FURS - Feasible Alternative For Renal Stones

X.2 Abstract

Urinary stone disease is a highly prevalent condition in Egypt. Management depends on stone site, size and composition and is based on an adequate grasp of endourologic techniques. The guidelines are grouped according to stone site in the urinary tract, with special sections for general recommendations and special conditions

X.2.1 Methods:
A comprehensive scoping effort covering all guidelines (American, European and Canadian) as regard to different patterns of urinary tract calculi was performed.

For each recommendation and advice in this overview, all of the following elements were highly considered:
  • Quality of evidence for this recommendation.
  • Impact of this practice on patient and oncological outcomes.
  • The balance between this practice and the different aspects of health service in our locality.

X.2.2 Results.
These guidelines represent the best clinical evidence-based medicine available. These guidelines are not solely based upon the level of evidence of the international publications but also include expertise of the treating doctor and expectations of every patient.

X.2.3 Conclusions.
These guidelines provide practical evidence-based guidance on the clinical aspect of Urinary tract calculi. The main target is entirely focused on assessment and treatment, reflecting the recommended clinical practice. This can provide the basis for thinking through patient’s management and also for planning and designing clinical services.

X.3 Introduction
Urinary stone disease is a highly prevalent disease worldwide, with significant variation in rates based on geography, climate, diet, fluid intake, genetics, sex, occupation and age. Egypt lies in a stone belt of increased incidence and the evolution of socioeconomic standards has led to a change in the pattern of stone disease in the country. (1-6)

Due to the significant impact of stone disease, a guidelines committee was developed to help Egyptian urologists incorporate recommendations into clinical practice based on current evidence based analysis. The aim being to establish a consensus on the treatment approach in keeping with our specific social environment and economic limitations.

The Guideline for Stone Diseases committee members meticulously reviewed the relevant references retrieved via the PubMed and MEDLINE databases. They also relied heavily on previous recommendations of esteemed international entities as:

(i) EAU Guidelines on Urolithiasis 2017, published by the EAU;
(ii) Surgical Management or Stones: AUA/Endourological Society Guidelines;
(iii) NICE Guideline – Renal and ureteric stones: assessment and management; and,
(iv) The Urological Association of Asia clinical guideline for urinary stone disease. (7-10)

Information was incorporated into a modified set of Egyptian Guidelines suitable for incorporation based on our socioeconomic limitations while incorporating evidence based rationale. (11) Having said this the best treatment also depends on the circumstances of each individual case and is not uniform so that the guidelines should be taken as an advisory not legally binding document that should be of benefit in case management.

X.4 General Recommendations and Precautions for Stone Removal
X.4.1 Antibiotic therapy:
Strong Recommendation:

A. UTI should always be treated if stone removal is planned.

B. Urine culture or urinary microscopy should be performed before treatment.

C. Patients with clinically significant infection and obstruction, drainage should be performed for several days before starting stone removal.

D. In absence of UTI SWL, does not require antimicrobial prophylaxis.

E. In URS and PNL antimicrobial prophylaxis is strongly recommended.

F. Patients undergoing PNL with sterile urine may still develop infectious complications including UTI and sepsis may be due to the presence of unsuspected bacteria within stones.

G. Antimicrobial prophylaxis is based primarily on prior urine culture results.
  1. Administered prior to stone intervention within 60 minutes of the procedure and repeated during the procedure if the case length necessitates.
  2. A single oral or IV dose.
  3. An antibiotic that covers both gram positive and negative uropathogens.

X.4.2 Obesity
A. Cohort studies concluded that individuals who are considered obese are more at risk of developing kidney stones.

B. Obesity link with an increased risk of developing kidney stone disease and influence the composition of the stones. High BMI is associated with high urinary oxalate, calcium and uric acid levels. Whilst calcium oxalate still composed the majority of stones formed, as BMI increases, the proportion of uric acid stones increases.

C. A high BMI can pose a higher anesthetic risk.

D. The proposed management of kidney stones ranges from patient lifestyle modifications to pharmacological management and invasive intervention.

E. Management plans should be tailored to individual patients and influenced by their BMI and the presence of metabolic syndrome.

F. The body habitus of an individual also influences the type of intervention that is most appropriate, with flexible URS/RIRS increasingly being the preferred option in obese patients.

G. Management of urolithiasis in patients with morbid obesity is usually associated with higher morbidity and mortality compared to non-obese patients.

H. SWL: The success rate is reduced, possible causes:
  1. Patient weight.
  2. Increase in skin to stone distance which leads to increased absorption of the shock wave.
  3. Difficulty in stone localization and radiolucency of urate stones, and therefore inability to focus the shock wave beam effectively.
  4. Increased likelihood of residual stone fragments.
  5. A BMI > 30 kg/m2 was also associated with an increased risk of renal haematoma, possibly due to inappropriately high energy usage, also, may be because many of these patients have concurrent hypertension and increased vascular vulnerability.

URS:
  1. In severe obesity, it is a more promising therapeutic option than SWL.
  2. Used as first-line therapy for ureteral and renal stones - Strong Recommendation.
  3. A safe option in obese patients (BMI > 30 kg/m2) with comparable SFRs and complication rates. However, in morbidly obese patients (BMI > 35 kg/m2) the overall complication rates double.

Flexible URS/RIRS:

Is a safe and effective approach for renal stone treatment in obese individuals, except it requires long operation time depending on the size, number, and location of stones and on the experience of the surgeon.

Currently, seems to be the most appropriate intervention for small stones and PCNL for larger stones in the obese population

PCNL:
  1. Is a particularly important therapeutic modality for obese individuals?
  2. Studies have assessed the intra- and postoperative outcomes of PCNL in obese patients with renal stones > 2 cm but with longer operative times and the stone-free rate is inferior.

X.4.3 Stone composition
A. Consider the stone composition before deciding the method of removal - Strong Recommendation.

B. Stone composition is suspected based on:
  1. Patient history.
  2. Former stone analysis of the patient.
  3. Hounsfield unit on NCCT.

C. Attempt to dissolve radiolucent stones - Strong Recommendation.

D. Hard stones for SWL:
  1. Brushite, calcium oxalate monohydrate, and cystine.
  2. Homogeneous stones with a high density on NCCT.

E. PNL, URS, and flexible URS/RIRS: alternatives to treat large SWL-resistant stones.

X.4.4 Contraindications of procedures
A. Contraindications of SWL:
  1. Uncontrolled UTIs.
  2. Bleeding diatheses: should be compensated for at least 24 hours before and 48 hours after treatment.
  3. Pregnancy: potential effects on the fetus.
  4. Severe skeletal malformations and severe obesity: prevent targeting of the stone.
  5. Arterial aneurysm in the vicinity of the stone.
  6. Anatomical obstruction distal to the stone.

B. Contraindications of URS:
  • Apart from general problems, for example with general anaesthesia or untreated UTIs, URS can be performed in all patients without any specific contraindications.

Contraindications of PNL:
  1. Uncontrolled UTI.
  2. Patients receiving anti-coagulant therapy: must be monitored carefully pre- and post-operatively. Anti-coagulant therapy must be discontinued before PNL.
  3. Pregnancy.
  4. Tumor in the presumptive access tract area.
  5. Potential malignant kidney tumor.

X.4.5 Recommendations of preoperative work-up
KUB has low accuracy for the diagnosis of urinary stones (sensitivity and specificity of KUB is 44-77%). It can be used only for detection of radiopaque calculi and for comparison during follow-up.(12,13)

US is radiation-free, cheap and readily available; but with low sensitivity/specificity (sensitivity 45% and specificity 94% for detecting ureteral stones) (14)

NCCT is highly sensitive and specific for the detection ureteric stones. (8,9) Low-dose NCCT (<4 mSv) is recommended for diagnosis of ureteric stones in patients with BMI <30 kg/m(15)

During Pregnancy radiation exposure is a major concern. Low-dose CT has a high positive predictive value (95.8%), as opposed to MRI (80%) and US (77%) for detection of ureteric stones. (16)

Magnetic resonance urography cannot be used to detect urinary stones, it can detect the location of obstruction in the ureter, and renal parenchymal morphology.

Pain relief, should not be delayed by imaging assessments

X.4.5.1 Radionuclide renal scan
The least invasive method for determining differential function

Detection of baseline renal function can be useful in assessment of treatment outcomes for upper urinary tract stones (17)

Clinicians may obtain a functional imaging study (DTPA or MAG‐3) if clinically significant loss of renal function in the involved kidney or kidneys is suspected.

In patients with ureteral stones causing obstruction the assessment of renal function by nuclear scan might not be accurate. Use of creatinine clearance from urine collected from PCN, compared with urine from contralateral percutaneous nephrostomy or self-voided urine can be used (13)

X.4.5.2 Re imaging
Can be performed for patients prior to surgery if:
  • Passage of stones is suspected
  • Stone movement will change management
  • Reimaging should focus on the region of interest to limit radiation exposure.
  • Repeat imaging can include KUB x-ray, renal/bladder US, or CT.

Table X:1 Pecommendation of preoperative work-up

Recommendations

Strength Rate
1. We recommend ultrasound (US) as a primary diagnostic imaging tool Strong
2. We recommend non-contrast-enhanced CT to confirm stone diagnosis in patients with acute flank pain Strong
3. We recommend KUB for follow up of radiopaque ureteric stones Weak
4. We recommend functional imaging study (DTPA or MAG‐3) if clinically significant loss of renal function in the involved kidney is suspected Weak
5. We recommend ultrasound as the preferred method of imaging during pregnancy Strong
6. We recommend low dose non-contrast CT during pregnancy as a last line Weak
7. We do not recommend Magnetic resonance urography (MRU) for evaluation of ureteral calculi Strong
X.4.6 Diagnostic imaging in children
Radiation exposure is a major concern for children; therefore, US is the initial imaging modality for children

Plain films (KUB radiography) : Used to identify radiopaque stones, and for follow-up.

Intravenous urography (IVU) : The need for contrast medium injection is a major drawback.

Table X:2 Diagnostics imaging in children

Recommendations

Strength Rate
1. Collect stone material for analysis to classify the stone type. Strong
2. We recommend ultrasound as first-line imaging for children with suspected renal colic Strong
3. We recommend kidney-ureter-bladder radiography (or low-dose non-contrast-enhanced computed tomography) if ultrasound will not provide the required information. Strong
X.5 Ureteral Stones
X.5.1 Recommendations of treatment for ureteral stone pain management
NSAIDs are effective for acute stone colic, and have better analgesic effect compared to opioids. (18,19)

Patients with ureteral stones treated with alpha1-blockers can reduce the number of pain episodes, the need for analgesic medication (diclofenac) and hospitalization. (18)
  • Offer intravenous paracetamol to adults, children and young people with suspected renal colic if NSAIDs are contraindicated or are not giving sufficient pain relief.
  • Consider opioids for adults, children and young people with suspected renal colic if both NSAIDs and intravenous paracetamol are contraindicated or are not giving sufficient pain relief.

Table X:3 Recommendations of treatment for ureteral stone pain management

Recommendation

Strength rating
1. We recommend non-steroidal anti-inflammatory drug (NSAID) as first-line treatment for patients with suspected renal colic. Strong
2. We do not recommend antispasmodics to adults, children and young people with suspected renal coli Strong
3. We recommend renal decompression or ureteroscopic stone removal in case of analgesic refractory colic pain. Strong
X.5.2 Recommendations for use of medical expulsive therapy
α1 receptor antagonists have the potential to inhibit ureteral spasm and uncontrolled contraction, theoretically reducing pain and promoting spontaneous stone passage. Tamsulosin significantly facilitated the passage of distal ureteral stones in patients with well-controlled pain, no infections, abnormal anatomy, renal insufficiency or high-grade obstruction. (16)

No improvement in stone passage rates was observed in patients with ≤5-mm distal ureteral stones. Stones of 5–10 mm showed a higher passage rate in the tamsulosin group. (20-22)

Experimental data on the effects of complete unilateral ureteral obstruction on renal function suggest the interval of conservative therapy should not exceed six weeks

α-blockers have been shown in multiple RCTs to have benefit for stent related discomfort. (23)

Patients treated with alpha blockers, calcium-channel inhibitors (nifedipine) and phosphodiesterase type 5 (PDE-5) inhibitors (tadalafil) are more likely to pass stones with fewer colic episodes than those not receiving such therapy. (24, 25)

Clinicians may offer antimuscarinic therapy to reduce stent discomfort.

PDE-5 Inhibitors or corticosteroids in combination with alpha blockers in MET can be made. (25)

Table X:4 Recommendation for use of medical expulsive therapy

Recommendations

Strength rating
1. We recommend alpha blockers as medical expulsive therapy as one of the treatment options for (distal) ureteral stones less than 10 mm. Strong
2. We recommend alpha blockers as an adjunct to SWL for adults with ureteric stones Weak
3. We recommend alpha blockers to reduce stent related discomfort. Weak
The Panel recommends a four to six-week interval for conservative treatment to reduce the potential for permanent damage. Furthermore, studies have indicated that most stones that pass do so within six weeks.

X.5.3 Role of medical chemolysis in uric acid stone
The role of medical chemolysis is to dissolve Uric acid stones.

Urinary pH is the most important factor in uric acid solubility. (22)

Oral alkaline citrate or sodium bicarbonate can be used for alkalinization of urine

The pH should be adjusted in the range of 7.0–7.2 to prevent formation of calcium phosphate calculi. (26)

No RCTs are available for this therapy.

Obstruction of the urinary tract by uric acid calculi can be treated by oral chemolysis in combination with urinary drainage. A combination of alkalinisation with tamsulosin can increase the frequency of spontaneous passage of distal ureteral uric acid stones.

Table X:5 Table 10:7: Stenting before shockwave lithotripsy

Recommendation

Strength Rating
1. We recommend oral chemolysis to dissolve pure uric acid stones Strong
2. We recommend monitoring patients during oral chemolysis of uric acid stones. Strong
3. We recommend oral chemolysis with tamsulosin in case of ureteral stones (if active intervention is not indicated or refused by the patient. Weak
4. We recommend treatment of obstructing uric acid calculi by oral chemolysis in combination with urinary drainage Strong
X.5.4 Stenting before shockwave lithotripsy
Some urologists place ureteral stents prior to SWL with the intention of improving stone-free rates or preventing complications. Both the 1997 AUA Guideline and the 2007 EAU/AUA Guideline for the Management of Ureteral Calculi recommended against routine stenting with SWL. (8,9)

Table X:6 Stenting before shockwave lithotripsy

Recommendation

Strength Rate
1. We do not recommend routine stenting to adults having shockwave lithotripsy for ureteric stones Strong
2. We recommend pre-stenting in patients having SWL for ureteric stones with Solitary kidney either anatomical or functional Strong
X.5.5 Guidelines for the management of sepsis and anuria
Ureteroscopy in presence of active, untreated infection can lead to life-threatening sepsis. The collecting system must be drained with a nephrostomy tube or a ureteral stent to allow drainage of infected urine and permit antibiotic penetration into the affected renal unit.

The mortality was higher in those not treated with surgical decompression compared to those who underwent drainage (19.2% vs 8.82%, p<0.001).The choice of drainage modality, stent or nephrostomy tube, is left to the urologist, as both have been shown to be equally effective. (27)

Table X:7 Guidelines for the management of sepsis and anuria

Recommendations

Strength rating
1. We recommend urgent drainage of the collecting system in case of sepsis with obstructing stones, using percutaneous drainage or ureteral stenting. Strong
2. We recommend to delay definitive treatment of the stone until sepsis is resolved. Strong
3. We recommend collecting urine again after decompression for antibiogram Strong
4. We recommend to start antibiotics immediately Strong
5. We recommend Re-evaluate antibiotic regimen following antibiogram findings. Strong
6. We recommend in severely ill patients and massively dilated kidney PCN decompression rather than stent unless the patient has bleeding diathesis Strong
X.5.6 Ureteroscopy (URS) (Retrograde and Antegrade, RIRS)
Endoscopic management is the standard approach for most stone removal. Surgery, open/laparoscopic/robotic-assisted may be required in selected situations
  • Stones requiring complete removal within a single session (infection stones)
  • Associated anatomical abnormalities requiring simultaneous reconstruction
  • Failed endoscopic surgery

The current standard for rigid ureteroscopes is tip diameters of < 8 F. Rigid URS can be used for the whole ureter. (28)

Technical improvements and availability of disposable digital scopes, has increased the use of flexible URS in the ureter.

Clinicians should use normal saline irrigation for URS.

Percutaneous antegrade removal of ureteral stones is a consideration in:
  • Large (>15mm), impacted proximal ureteral calculi in a dilated renal collecting system
  • When the ureter is not amenable to retrograde manipulation. (29)

X.5.7 Anesthesia
Endoscopy for the upper urinary tract can be performed under general anesthesia, although local or spinal anesthesia is possible. Intravenous sedation is suitable for female patients with distal ureteral stones. (30)

X.5.8 Safety aspects
Fluoroscopic equipment must be available in the (OR).

We recommend placement of a safety wire.

Balloon and plastic dilators should be available.

Start with small diameter long semi-rigid URS for optical dilatation followed by flexible URS, if required.

If the URS does not pass due to tight ureter, insertion a JJ stent for seven to fourteen days then try again. (31)

Bilateral URS during the same session is possible with minor increase in complications.

The limitations of semi-rigid URS are overcome by flexible URS. Flexible URS comes with higher success rates with low complications for < 2 cm proximal ureteral stones. (32)

Table X:8 Recommendation on Safety Precautions during URS

Recommendations

Strength rating
1. We recommend using a safety GW in all ureteroscopic procedures Strong
2. We recommend using small diameter URS at the start for optical dilation followed by flexible URS if required Strong
X.5.9 Intracorporeal lithotripsy
X.5.9.1 The Holmium: Yttrium-Aluminium-garnet (Ho: YAG) laser:
The most effective lithotripsy system. The holmium laser can be activated 0.5 mm from the urothelial surface without risk of injury. It is considered the standard for URS and flexible nephroscopy. (33)

X.5.9.2 Pneumatic and US systems:
Used with high disintegration efficacy in rigid URS. (33)

Stone migration is a common problem that can be avoided by placement of special anti-migration device

Medical expulsion therapy following Ho: YAG laser lithotripsy increases SFRs and reduces colic episodes.

EHL can damage the ureteral mucosa, resulting in ureteral perforation. The expanding cavitation bubble generated by the spark may produce injury to the mucosa with reported rates of ureteral injury of 8.5%-17.6%. (34)

Table X:9 intracorporeal lithotripsy

Recommendations

Strength Rating
1. We recommend the pneumatic and US systems with rigid URS. Strong
2. We recommend use of holmium: YAG laser lithotripsy for flexible ureteroscopy. Strong
3. We recommend stone extraction only under direct endoscopic visualisation of the stone Strong
4. We do not recommend EHL for intra-ureteral lithotripsy Strong
X.5.10 Stenting before and after URS:
Pre-stenting facilitates ureteroscopic management of stones, improves the SFR, and reduces intra-operative complications.

Routine stenting after uncomplicated URS is not necessary. Stenting might be associated with higher post-operative morbidity and costs. A ureteral catheter for (one day) may be used. A number of randomized prospective trials have questioned stent placement for uncomplicated URS. (35-37)

X.5.10.1 Post-operative Stents should be inserted in patients who are at increased risk of complications:
Ureteral trauma, Residual fragments, Bleeding, Perforation, UTIs, Pregnancy and Solitary kidney to avoid stressful emergencies.

The ideal duration of stenting is not known. The duration of ureteral stenting post-operatively should be minimized. Most urologists favor 1-2 weeks after URS. Alpha-blockers reduce the morbidity of ureteral stents and increase tolerability. (60-61)

Table X:10 Stenting before and after URS

Recommendations

Strength rating
1. Shorten the duration of post URS stent in uncomplicated cases. Strong
2. Insert stent in all cases where you may need to insert it as emergency (Residual fragments, single kidney, ureteral trauma…) Strong
3. We recommend pre-stenting in cases of tight ureter not admitting the small diameter URS. Strong
X.5.11 Complications of ureteroscopy
The overall complication rate after URS is 9-25%. Most complications are minor and do not require intervention. Ureteral avulsion and strictures are rare (< 1%). (28,38)

A safety guide wire should be used for most endoscopic procedures. It can provide access to the collecting system in cases of ureteric or collecting system injury, including perforation or avulsion. This will facilitate placement of an internalized stent in such cases.

X.5.11.1 There are situations where a safety guidewire cannot be placed (impacted ureteral stone)
  • Try a hydrophilic guidewire
  • Place the guide wire under vision using a small diameter URS
  • Leave the wire below the stone, carefully fragment the stone until the proximal ureteral lumen is identified and a safety wire placed.
  • Antegrade treatment using Flexible URS
  • Place a nephrostomy tube or antegrade stent and performing stone removal at a different time.

X.5.12 Contraindications of URS
Apart from general problems, for example with general anaesthesia or untreated UTIs, URS can be performed in all patients without any specific contraindications.

Complications are minor and do not require intervention

The following complications are the most relevant sepsis; ureteral stricture; ureteral injury; and UTI.

Serious complications, including death and loss of kidney, are sufficiently rare

Table X:11 Recommendation during ureteroscopy

Recommendations

Strength rating
1. We recommend having Fluoroscopic equipment available in the (OR). Strong
2. We recommend placement of a safety wire in all ureteroscopic procedures Strong
X.5.12.1 Indications for active removal of ureteral stones
Indications for active removal of ureteral stones are: (28)
  • Stones with a low likelihood of spontaneous passage;
  • Persistent pain despite adequate analgesic medication;
  • Persistent obstruction
  • Renal insufficiency (renal failure, bilateral obstruction, or single kidney).

X.5.13 Selection of procedure for active removal of ureteral stones
Large stones achieve earlier stone-free status with URS compared to SWL.

URS has greater potential for complications. The complication rate and morbidity of URS have now been significantly reduced. (38) Ureteroscopy is a safe option in obese patients (BMI > 30 kg/m2) (39)

X.5.13.1 Bleeding disorder
Ureteroscopy can be performed in patients with bleeding disorders, with a moderate increase in complications (40)

Table X:12 Recommendation for ureteric stones management in patients with bleeding tendecny

Recommendations

Strength Rating
1. We recommend URS as having a better chance of achieving stone-free status with a single procedure. Strong
2. Ureteroscopy has higher complication rates when compared to shock wave lithotripsy. Strong
3. In cases of morbid obesity use URS as first-line therapy for ureteral stones. Strong
X.5.14 Treatment algorithm for ureteral stones (if active stone removal is indicated)
Table X:13 Treatment algorithm for ureteral stones (if active stone removal is indicated)

Proximal ureteral stones
< 1cm SWL or URS
1-2 cm 1-URS antegrade or retrograde
2-SWL
>2 cm 1-URS
2-open/laparoscopic/Antegrade PNL

Distal Ureteral stones
<1 cm SWL or URS
>1 cm 1-URS
2-open/laparoscopic surgery
X.5.14.1 Excerpts from AUA/Endourology Society Guidelines
  1. Patients with uncomplicated ureteral stones <10 mm should be offered observation including MET with α-blockers. Stones of 5– 10 mm showed a higher passage rate using tamsulosin, by relaxing ureteral smooth muscle and decreasing the ureteral wall tone. (21)
  2. Offer surgical treatment (including SWL) to adults with ureteric stones and renal colic within 48 hours of diagnosis or readmission, if pain is ongoing and not tolerated or the stone is unlikely to pass.
  3. In most patients, if observation with or without MET is not successful after four to six weeks and/or the patient/clinician decide to intervene sooner based on a shared decision making approach, clinicians should offer definitive stone treatment.
  4. Clinicians should inform patients that SWL is the procedure with the least morbidity and lowest complication rate, but URS has a greater stone-free rate in a single procedure.
  5. In patients with mid or distal ureteral stones who require intervention (who were not candidates for or who failed MET), clinicians should recommend URS as first-line therapy. For patients who decline URS, clinicians should offer SWL.
  6. In patients who fail or are unlikely to have successful results with SWL and/or URS, clinicians may offer PCNL, laparoscopic, open, or robotic assisted stone removal.
  7. If initial SWL fails, clinicians should offer endoscopic therapy as the next treatment option. Strong recommendation.
  8. Clinicians should use URS as first-line therapy in most patients who require stone intervention in the setting of uncorrected bleeding diatheses or who require continuous anticoagulation/antiplatelet therapy Strong Recommendation.

Furthermore, Clinicians performing URS for proximal ureteral stones should have a flexible ureteroscope available, or be ready for stenting and SWL in case of migration.

Performing semi-rigid URS in the proximal ureter may not be possible, and carries a higher risk of ureteral injury

The semi-rigid ureteroscope may be unable to pass the angulation of the ureter associated with a large prostate or the iliac vessels.

Semi-rigid URS above the level of the iliac vessels can cause additional torque on the ureteroscope, with a risk for damage. These limitations are overcome by flexible URS.

Flexible URS has been shown in both prospective and retrospective studies to have high overall success rates with low morbidity/complications for < 2 cm proximal ureteral stones. Failure and retreatment rates are higher in the proximal ureter for semi-rigid URS compared to flexible URS. (38)

X.5.14.2 Laparoscopy and open surgery
Open/ laparoscopic /robotic surgery should not be offered as first-line therapy to most patients with stones. When expertise is available, laparoscopic ureterolithotomy can be performed for large proximal ureteral stones as an alternative to URS or SWL (41)

These more invasive procedures have yielded high SFRs and lower auxiliary procedure rates

Open surgery should be considered as the last treatment option, after other possibilities have been explored.

Table X:14 Recommendation on Laparoscopy and/or open surgery for ureteric stones

Recommendation

Strength Rating
We recommend laparoscopic or open surgical stone removal in rare cases in which shock wave lithotripsy, retrograde or antegrade ureteroscopy and percutaneous nephrolithotomy fail, or are unlikely to be successful. Strong
X.5.15 Ureteroscopy in Pregnancy
MET appears safe in the pregnant population. (42)

In pregnant patients with ureteral stones, clinicians may offer URS to patients who fail observation.

Ureteroscopy is best performed by an experienced urologist and at an institution that has obstetric support for both maternal and fetal care. Ureteral stent and nephrostomy tube are alternative options. Frequent stent or tube changes are usually necessary. (43)

Non-urgent ureteroscopy in pregnant women should be best performed during the second trimester. (43)

Table X:15 Recommendation for ureteric stone management during pregnancy

Recommendation

Strength Rating
1. Treat ureteral calculi during pregnancy conservatively (except when there are clinical indications for intervention). Strong
2. Ureteroscopy can be done safely during pregnancy to avoid long term stenting and drainage Strong
X.5.16 Treatment for pediatric patients with ureteral calculi:
In children, the indications for SWL, URS and PNL are similar to those in adults.

In pediatric patients with uncomplicated ureteral stones ≤10 mm, clinicians should offer observation with or without MET using α-blockers.

Clinicians should offer URS or SWL for pediatric patients with ureteral stones who are unlikely to pass the stones or who failed observation and/or MET, based on patient-specific anatomy and body habitus.

X.5.17 Rigid/semi-rigid ureteroscopy in children:
In recent years ureteroscopy is increasingly used in children with ureteral stones. Ureteroscopy proved to be effective with SFR of 81-98%, retreatment rates of 6.3%-10% and minor complications. Preliminary stenting has not proven necessary. (44-46)

Table X:16 Recommendation on management of ureteric stones in children

Recommendations

Strength rating
1. Offer children with single ureteral stones less than 10 mm shock wave lithotripsy (SWL) if localisation is possible as first line option. Strong
2. Ureteroscopy is a feasible alternative for ureteral stones not amenable to SWL. Strong
URS requires particularly skilled and experienced endo-urologists in the following conditions:
  • Morbidly obese patients
  • Pregnancy
  • Children
  • Patients with bleeding diathesis
  • Previous open surgery at the same level
  • Huge prostate size
  • Patients with skeletal deformities

X.6 Renal Stones
X.6.1 Diagnosis
A complete urinalysis is essential, and if clinical or laboratory signs of infection are present, urine culture is additionally required. Serum creatinine is particularly appropriate in presence of infection and bilateral affection or associated medical disease, and a complete blood count is essential prior to intervention.

Non-contrast CT of the urinary tract has become the standard evaluation for renal calculi. It has proven superior to a combination of Ultrasound and plain x-ray. It defines stone burden and distribution, gives an idea about stone composition as well as collecting system anatomy and so guides management decisions. In case of complex stones or anatomy, additional contrast imaging may be necessary. (47-49)

A radioisotope renal study is the standard to assess renal function if significant renal loss is suspected. IV, CT and MR Urography are adequate alternatives and parenchymal thickness can also give a rough guide to renal function. 50

Sepsis with an obstructing stone is an indication for urgent drainage and antibiotic therapy prior to definitive stone management.

X.6.2 Treatment of Renal Stones
X.6.2.1 Conservative Options
There is still no consensus on the optimal management of small, non-obstructing, asymptomatic calculi. Active surveillance appears to be the best option for asymptomatic renal stones less than 5 mm, and some renal stones in the 5-10 mm range, with active intervention in case of stone growth or development of symptoms. (51,52)

Chemolysis by alkalinisation is the best management for uric acid calculi in the absence of infection or marked back pressure. 53

Table X:17 Recommendations for Conservative management of renal stones

Recommendations

Strength rating
1. Asymptomatic calyceal calculi <1cm may be followed up Weak
2. On active follow-up stone growth, de novo obstruction, associated infection, and acute and/or chronic pain are indications for treatment. Strong
X.6.2.2 Active Stone Removal
According to the EAU Guidelines,8 indications for the removal of renal stones, include:
  • Stone growth;
  • Stones in high-risk patients for stone formation;
  • Obstruction caused by stones;
  • Infection;
  • Symptomatic stones (e.g., pain or haematuria);
  • stones > 15 mm;
  • Stones < 15 mm if observation is not the option of choice;
  • Patient preference;
  • Comorbidity;
  • Social situation of the patient (e.g., profession or travelling)

Choices for active intervention include ESWL, PCNL and open surgery/laparoscopy.

X.6.2.3 Selection of procedure for active removal of renal stones
X.6.2.3.1 Stones in renal pelvis or upper/middle calices

It is the consensus that in patients with a total renal stone burden >20 mm, clinicians should offer PCNL as first-line therapy. If this is not feasible then RIRS may be considered with the knowledge that it may take several sessions. Open surgery/laparoscopy should be kept as a last option, and ESWL is not a suitable choice in this situation. (8-10)

For stones ≤ 20 mm, ESWL and RIRS are acceptable alternatives to PCNL. (8-10)

X.6.2.3.2 Stones in the lower renal pole

Clearance of fragments from the lower pole is lower than other sites. Consequently, ESWL is only indicated if stone size is < 10mm although it can be chosen if factors affecting clearance are considered particularly favorable. If available, RIRS might be a more suitable option for such calculi. PCNL is also an option, and it is the primary choice for all larger calculi. (8-10)

X.6.2.4 ESWL
Successful lithotripsy depends on fragmentation and clearance and this is directly affected by stone composition, site and size. (54,55)

If the stone density is greater than 1000HU it is resistant to fragmentation. Calculi > 20mm require multiple treatments, and their clearance is associated with a higher incidence of ureteral obstruction (colic or steinstrasse) often requiring adjunctive procedures. For the lower pole, calculi > 10mm are associated with an unacceptable stone free rate. (54,55)

ESWL is best suited for renal calculi < 20mm. In the lower pole it is best reserved for calculi < 10mm. (54,55) and it is markedly affected by calyceal anatomy. (56-57) Otherwise, it should not be offered as first-line therapy.

The EAU guidelines summarised factors adversely affect SWL as follows 8
  • Steep infundibular-pelvic angle;
  • Long calyx;
  • Long skin-to-stone distance;
  • Narrow infundibulum;
  • Shock wave-resistant stones (calcium oxalate monohydrate, brushite, or cystine).

SWL should not be considered if there is obstruction distal to the stone.

α-blocker therapy may be offered to facilitate passage of fragments, and stone material is best collected for analysis.

Table X:18 Recommendations for management of lower pole calculi

Recommendations

Strength rating
1. PCNL and RIRS are better options for lower pole calculi unless factors are particularly favorable for clearance Strong
X.6.2.5 Retrograde Infrarenal Surgery
RIRS is an acceptable option for renal calculi < 20mm. It provides an attractive alternative to SWL but it’s use is limited by the high cost of the necessary equipment. This is accentuated by the fragility of the flexible instruments. The introduction of disposable flexible ureteroscopes has somewhat mitigated this issue. (54,55)

X.6.2.6 PCNL
Percutaneous nephrolithotomy is the primary option in renal stones > 2 cm.

It should be done under antimicrobial coverage, and the procedure should be aborted by placement of a percutaneous nephrostomy if purulent urine is encountered. On the other hand, placement of a nephrostomy tube is optional in an incident free PCNL, if the patient is considered stone free.

Mini-PCNL with 14–20-Fr tracts have proven as effective as standard PCNL in a variety of situations with a higher safety profile. 58

Table X:19 Recommendation for renal stone management

Recommendations

Strength rating
1. PCNL is the primary treatment option for renal calculi > 2cm Strong
X.6.2.7 Open/Laparoscopic Surgery
Open/Laparoscopic surgery is not the first option for stone management. It is only indicated with especially large/complex stones and in case of certain anatomic considerations.

X.6.2.8 Special Situations
Staghorn calculi are not suitable for observation and should be actively managed if possible. The best option is PCNL but anatomy and stone configuration might necessitate open surgery. Both options are technically demanding and are best left to tertiary referral centres that are adequately equipped and have a high-volume practice.

Stones in calyceal diverticulum are a similar situation that are best managed endoscopically in a high volume centre.

In patients with calculi that necessitate intervention in a kidney with negligible function, nephrectomy is an acceptable option. This is often a difficult procedure with high complication rates that exceed that for radical nephrectomy. 59

Table X:20 Recommendation for staghorn stone

Recommendations

Strength rating
1. Staghorn calculi should be actively managed whenever possible. Strong
X.7 Management of Specific Patients’ Groups
X.7.1 Stones in pregnant patients:
A. Urolithiasis is the most common cause of non-obstetrical abdominal pain that requires hospitalization in pregnant women.

B. Stones during pregnancy is often a diagnostic and therapeutic challenge:
  1. Many signs and symptoms of urolithiasis can be found in a normal pregnancy or may be associated with broad differential diagnoses of other sources of abdominal pathology including appendicitis, diverticulitis, or placental abruption.
  2. Investigations are complicated by the normal changes during pregnancy that can resemble obstructing calculi.
  3. Standard imaging and treatment algorithms can pose undo risk to the developing fetus.
  4. The risks to the fetus of ionizing radiation, analgesics, antibiotics, and anesthesia must also be considered.
  5. Most stones pass spontaneously with conservative treatment. However, if the calculus does not pass, ureteral obstruction, upper urinary tract infection, urosepsis, or perinephric abscess may occur.
  6. May precipitate premature labor or interfere with the progression of normal labor, which poses a significant health risk to the fetus.
  7. These factors can cause a delay or inappropriate diagnosis difficult decisions.

C. Evaluation and management is complex and must be multidisciplinary:
  1. It demands close collaboration between patient, radiologist, obstetrician and urologist.
  2. The obstetrician or maternal fetal medicine physician, anesthesiologist, and urologist must work together to develop a safe and effective plan for the patient.
  3. Coordinate pharmacological and surgical intervention with the obstetrician.
  4. Should medication be given, the obstetrician or maternal fetal medicine physician along with the pharmacist can insure medications prescribed are safe to the developing fetus based on gestational age at time of presentation.
  5. Should ionizing radiation is necessary for diagnostic or treatment purposes, the radiation physicist along with the obstetrician can estimate radiation exposure so the total pregnancy exposure does not exceed the American College of Obstetrics and Gynecology (ACOG) recommended maximum of 50 mGy.
  6. Although obstetric complications at time of surgical intervention are rare (<5%), the patient should only be undertaken by clinicians facile with the treatment approach and at an institution that has both the equipment required for URS and obstetric support for managing maternal and fetal emergencies should complications ensue intra or post operatively.

D. Treat all uncomplicated cases of urolithiasis in pregnancy conservatively (except when there are clinical indications for intervention) - Strong Recommendation.

E. Conservative treatment and MET: pregnant patients with ureteral stone(s) and well controlled symptoms:
  1. Offer observation as first-line therapy - Strong recommendation.
  2. Spontaneous passage rates are not different than in non-pregnant patients.
  3. Be aware that a stone event in pregnancy carry an increased risk of maternal and fetal morbidity.
  4. Close follow-up for recurrent or persistent symptoms.
  5. The patient should be counseled that MET has not been investigated in the pregnant population, and the pharmacologic agents are being used for an “off-label” remain debatable.
  6. For analgesia:
    a) NSAIDs: are contraindicated, not recommended during the first 20 weeks of pregnancy. Associated with an 80% increased risk of miscarriage, also linked to renal congenital abnormalities and fetal pulmonary hypertension and may cause premature closure of the ductus arteriosus.
    b) Acetaminophen for mild analgesia.
    c) Morphine: frequent small doses used safely in severe pain.

F. Should surgical intervention be warranted, the multidisciplinary team is imperative, utilizing an anesthesiologist who specializes in obstetrics to perform fetal monitoring, if indicated, and to keep drug exposure to the minimum.

G. Ureteral stent or percutaneous nephrostomy tube placement:
  1. Indication:
    a) Patient who fail observation.
    b) If complications develop (e.g., infection, intractable symptoms), severe hydronephrosis, large or bilateral stones, abnormal anatomy, or obstetric complications (induction of premature labour).
    c) When definitive surgical treatment is not advisable or available.
    d) When there is insufficient multidisciplinary support and/or scant endourological or anesthetic resources available.
  2. Ureteral stent and nephrostomy tube are options with frequent stent or tube changes usually being necessary - Strong Recommendation
  3. Both, double-J catheter and nephrostomy tube are equally effective in draining an infected collecting system and it is up to the urologist to choose which one is the most appropriate for each situation.
  4. Effectively decompress obstructed collecting system and bring symptom relief.
  5. Associated with poor tolerance and require multiple exchanges due to the potential for encrustation.

H. SWL: Pregnancy is an absolute contraindication for SWL.

I. If intervention becomes necessary, place a ureteral stent or a percutaneous nephrostomy tube as readily available primary options - Strong Recommendation.

J. URS:
  1. For patients who fail observation
  2. A definitive treatment as it accomplishes stone clearance.
  3. Reasonable alternative to avoid long-term stenting / drainage (until delivery). It results in fewer needs for stent exchange, less irritative LUTS and better patient satisfaction by obviating prolonged drainage.
  4. Can be done with limited X-ray emission, using shield protection at the patient's pelvis, or completely US-guided only.
  5. Non-urgent ureteroscopy in pregnant women should be best performed during the second trimester, by an experienced urologist.
  6. Counselling should include access to neonatal and obstetric services.

K. PNL:
  1. Feasible but remain an individual decision.
  2. Should be generally avoided.
  3. Should be performed only in experienced centres.

L. Diagnosis:
  1. Ideally, no ionizing radiation should be used in the first or second trimesters, if at all possible. Radiation exposure in the third trimester is less of a risk to the fetus.
  2. Guidelines available from the American College of Obstetricians and Gynecologists stress the need to weigh the risks of exposure to radiation and contrast agents with the risk of non-diagnosis and worsening of disease. Fetal risk of anomalies, growth restriction, or abortion have not been reported with radiation exposure of less than 50 mGy, a level above the range of exposure for most diagnostic procedures.
  3. The EAU guidelines recommend US for the diagnosis of urolithiasis during pregnancy. However, the guidelines note that normal physiologic changes in pregnancy can mimic ureteral obstruction and the role of US is limited in acute obstruction because it cannot properly differentiate causes of dilation. MRI is recommended as a second-line imaging study, but use of low-dose CT is restricted to selected cases.
  4. Ultrasound:
    a) Renal with or without Doppler studies and bladder US has become the first line option for imaging pregnant women with renal colic.
    b) Transvaginal US can add important information as it better evaluates the distal ureter and ureteral-vesical-junction.
    c) Although less specific and sensitive compared to CT scans, it is harmless to the patient and fetus.
  5. Intravenous urography (IVU or IVP) :
    a) Is reserved for more complex cases.
    b) If US findings are equivocal and clinical symptoms strongly suggest renal calculi.
    c) Limited IVP with reduced films and radiation exposure: has been shown to successfully reveal calculi without the high radiation dose of full IVP.
    d) If the US and limited IVP test findings are unclear, additional tests or procedures may be indicated, depending on the clinical scenario. However, many experts suggest proceeding directly to URS for diagnosis and treatment when this procedure is indicated, especially in the first and second trimesters.
  6. CT scans:
    a) Limited CT scanning.
    b) Reserved for more complex cases.
    c) Used if US and limited IVP test findings are unclear.
    d) Avoided due to the high X-ray emission and its potential teratogenic effects (particularly in the first trimester).
    e) Nevertheless, it has been shown that radiation doses of less than 50 mGY during pregnancy are not associated with higher risk of malformation or pregnancy loss.
    f) The judicious use of low dose CT scan protocols that expose the fetus to lower radiation doses and maintain diagnostic accuracy, can be an option.
  7. MRI/MRU:
    a) Recently, non-contrast MRU has been used with a better accuracy than US and is used by some as second line to US.
    b) Has limited utility in urinary stone disease and during pregnancy.
    c) Visualizes stones poorly; it cannot demonstrate the actual stone, only the point of obstruction.
    d) Provide a benefit in its ability to reveal non–urinary-tract pathology that may manifest with similar symptoms (ie, ovarian torsion, appendicitis).
    e) MRU can be used to differentiate a physiological upper tract dilatation from a pathologic ureterohydronephrosis during pregnancy and to ascertain whether the obstruction is intrinsic or extrinsic.
    f) Does not use ionizing radiation or iodinated contrast, but its use during the first trimester is not recommended because its effect on fetal development is not clear.
    g) Other disadvantages include expense, discomfort for the pregnant patient, and a lack of availability.
  8. Nuclear renography is reserved for functional studies to direct treatment, of limited value during pregnancy

X.7.1.1 Stones in patients with urinary diversion:
A. These patients are at high risk for stone formation. One study has shown that the risk for recurrent upper tract stones in patients with urinary diversion subjected to PNL was 63% at five years.

B. Site: renal collecting system, ureter, the conduit, or continent reservoir.

C. Causes:
  1. Metabolic factors (hypercalciuria, hyperoxaluria and hypocitraturia).
  2. Infection with urease-producing bacteria.
  3. Foreign bodies.
  4. Mucus secretion.
  5. Urinary stasis.

D. Management
  1. Smaller upper-tract stones: SWL is an effective treatment.
  2. In majority of cases, endourological techniques are necessary to achieve stone-free status.
  3. The choice of access depends on the feasibility of ureteric orifice identification in the conduit or bowel reservoir.
  4. Stones in a conduit:
    a) Perform a Trans-stomal approach.
    b) Remove all stone material (along with the foreign body).
    c) Use standard techniques, including intracorporeal lithotripsy and flexible endoscopes.
    d) Manipulations must be performed carefully to avoid disturbance of the continence mechanism.
  5. Patients with long, tortuous conduits or with invisible ureter orifices: retrograde endoscopic approach might be difficult or impossible.
  6. PNL is indicated in - Strong Recommendation:
    a) Large renal stones.
    b) Antegrade URS for stones that cannot be accessed via retrograde approach.
    c) Ureteral stones that are not amenable to SWL.
  7. Before considering PNL:
    a) CT should be done to assess the presence of an overlying bowel which could make this approach unsafe.
    b) If overlying bowel, an open surgical approach should be considered.

E. Prevention :
  1. Recurrence risk is high.
  2. Metabolic evaluation and close follow-up are necessary.
  3. Measures:
    a) Medical management of metabolic abnormalities.
    b) Appropriate therapy of urinary infections.
    c) Hyperdiuresis or regular irrigation of continent reservoirs.

X.7.2 Stones in patients with neurogenic bladder:
A. Patients undergoing urinary diversion and/or suffering from neurogenic bladder dysfunction are at risk for recurrent stone formation.

B. Risk factors:
  • Bacteriuria.
  • Hydronephrosis.
  • VUR.
  • Renal scarring.
  • Lower urinary tract reconstruction.
  • Thoracic spinal defect.

C. Site:
  1. At any level of the urinary tract.
  2. Bladder: more frequently especially if augmentation has been performed.

D. Causes:
  1. Urinary stasis.
  2. Infection.
  3. Indwelling catheters (facilitate UTI).
  4. Surgical interposition of bowel segments (facilitate UTI).

E. Diagnosis:
  1. May be difficult and delayed, causes:
    a) Absence of clinical symptoms due to sensory impairment.
    b) Vesico-urethral dysfunction.
  2. Difficulties in self-catheterisation should lead to suspicion of bladder calculi.
  3. Imaging studies are needed (US, CT) to confirm diagnosis prior to intervention.

F. Management
  1. Take appropriate measures regardless of the treatment provided since in myelomeningocele patients latex allergy is common - Strong Recommendation.
  2. Surgery must be performed under general anaesthesia because of the impossibility of using spinal anaesthesia.
  3. Bone deformities often complicate positioning on the operating table.

G. Prevention:
  1. Appropriate infection control.
  2. Restoration of normal storing/voiding function of the bladder if available.
  3. Correction of the metabolic disorder.
  4. After augmentation cystoplasty in immobile patients with sensory impairment, irrigation protocols significantly reduce the risk of stone formation.

X.7.3 Management of stones in patients with transplanted kidneys
A. Incidence 1%.

B. Stones can either be transplanted or present de novo.

C. Risk factors for de novo stone formation: multifactorial
  1. Dependency on a solitary kidney.
  2. Immunosuppression: increases the risk of recurrent UTIs.
  3. Biochemical and metabolic causes:
    a) Hyperfiltration.
    b) Excessively alkaline urine.
    c) Renal tubular acidosis (RTA).
    d) Increased serum calcium due to persistent tertiary hyperparathyroidism.

D. Diagnosis:
  1. Usually detected by routine US examination.
  2. NCCT indicated in unclear cases.
  3. Perform US or NCCT to rule out calculi in transplanted patients with unexplained fever, or unexplained failure to thrive (particularly in children) - Weak Recommendation.

E. Management
  1. Being a solitary kidney that maintain the patients’ renal function, any impairment in urinary stasis/obstruction require immediate intervention or drainage.
  2. Selecting the appropriate technique is difficult.
  3. Principles are similar to those applied in other single renal units.
  4. Factors influencing the surgical strategy:
    a) Transplant function.
    b) Coagulative status.
    c) Anatomical obstacles due to the abnormal iliacal position of the transplanted kidney.
  5. Complete metabolic evaluation after stone removal - Strong Recommendation.
  6. Small asymptomatic stones - Conservative but:
    a) Close surveillance.
    • Absolutely compliant patients.
    b) Offer patients with transplanted kidneys, any of the contemporary management options, including SWL, flexible URS/RIRS and PNL - Weak Recommendation.

    c) SWL:
    • For small calyceal stones - option.
    • Minimal risk of complication.
    • Stone localisation can be challenging:
      • Position of the graft close to the iliac bone.
      • Might potentially lessen the effectiveness of the shock waves.
      • Might preclude fluoroscopic stone localisation.
    • Repeated sessions might be required for complete disintegration representing further burden to the patient.
    • SFRs are poor (combining with RIRS might clear residuals).
    • Close follow-up is mandatory: the graft is eventually left with stone debris that while passing through the ureter might induce silent ureteral obstruction.
  7. Large or ureteral stones:
    a) Careful percutaneous access and antegrade endoscopy using flexible URS/RIRS or nephroscope: favorable.
    b) Percutaneous access performed in the supine position.
    c) Be aware of potential injury to adjacent organs (bowel), consequently extreme care is required and a more lateral puncture should be performed cautiously.
    d) Extreme caution should be taken as the fibrosis around the graft renders the procedure considerably difficult.
    e) Access to the pelvicalyceal system is commonly performed through an anterior calyx in the upper pole (alternatively a middle calyx) facilitated by US guidance preferably combined with fluoroscopic guidance.
    f) Antegrade Double-J stent is routinely fixed at the end of the procedure.
    g) Mini-PNL has recently been suggested with small track size inducing less parenchymal injury.
    h) Retrograde access: difficult because of
    • Anterior location of the ureteral anastomosis.
    • Ureteral tortuosity.
    i) Flexible URS/RIRS:
    • A valid treatment option.
    • Outperforming conventional semirigid URS with minimal morbidity.
    • Unusual location of the ureteral orifice could be overcomed by:
      • Applying suprapubic pressure.
      • Evaluating the bladder at different levels of filling.
      • Use 70° lens.
    j) Open surgery - Reserved for:
    • More complex cases resulting from ureteral stenosis.
    • Transplant in context of urinary diversion.
    • Stones formed around missed stents.
    k) Complete metabolic evaluation after stone removal - Strong Recommendation.

X.7.4 Management of stones in children
X.7.4.1 General considerations:
  1. Stone disease in the children has been reported to be increasing.
  2. At present, our understanding of stone management is somewhat rudimentary, as the published literature is sparse.
  3. Future efforts to better define the effects of surgical stone treatment in this population will also be important.
  4. In children, the indications for SWL, URS and PNL are similar to those in adults.

X.7.4.2 Incidence:
  1. The true incidence is unclear due to the global lack of large epidemiological studies.
  2. Data derived from nation-wide epidemiological studies performed in different counties worldwide, and large-scale databases indicate that the incidence and prevalence of pediatric urinary stone disease has increased over the last decades.
  3. Although boys are most commonly affected in the first decade of life, the greatest increase in incidence has been seen in older female adolescences.

X.7.4.3 Stone composition:
  1. Similar as in adults with predominance of calcium oxalate stones.
  2. Metabolic abnormalities are less commonly identified in children.
  3. Age may affect the predominant metabolic abnormality:
    a) Hypocitraturia most common disorder in children >10 years old.
    b) Hypercalciuria most common disorder in children <10 years old.
  4. Genetic or systemic diseases:
    a) Example: cystinuria or nephrocalcinosis.
    b) Rare, <17% of the identifying causes.
  5. The role of diet: Unclear. Some evidence:
    a) Low urine volume.
    b) Children are drinking less water.
    c) Children are taking greater daily amounts of sodium than is recommended.

X.7.4.4 Clinical presentation:
  1. Symptoms are age-dependent in the form of pain, hematuria or UTI.
  2. Can be asymptomatic or present with non-specific symptoms that necessitate a high index of suspicion for proper diagnosis.
  3. Infants: present with crying, irritability and vomiting (40% of cases).
  4. Older children: flank pain, micro or gross- haematuria and recurrent UTIs.

X.7.4.5 Diagnostic imaging:
  1. Children with urinary stones have a high risk of recurrence; therefore, standard diagnostic procedures for high-risk patients apply, including a valid stone analysis.
  2. Complete a metabolic evaluation based on stone analysis - Strong Recommendation.
  3. Collect stone material for analysis to classify the stone type - Strong Recommendation.
  4. The most common non- metabolic disorders facilitating stone formation:
    a) VUR.
    b) UPJO.
    c) Neurogenic bladder.
    d) Other voiding difficulties.
  5. The principle of ALARA (As Low As Reasonably Achievable) should be observed.
  6. When selecting diagnostic procedures, it should be remembered that these patients might be:
    a) Uncooperative.
    b) Require anaesthesia.
    c) May be sensitive to ionizing radiation.
  7. Increased awareness of the potential adverse effects of ionizing radiation in children has led to efforts to reduce radiation exposure in this population.
  8. Children may be more susceptible to radiation-induced injury due to their rapidly developing tissues, and they have a longer potential lifespan during which radiation-induced illness may manifest.
  9. US:
    a) The first-line imaging modality when a stone is suspected (it should include the kidney, fluid-filled bladder and the ureter next to the kidney and the bladder) - Strong Recommendation.
    b) Colour Doppler US shows differences in the ureteral jet and resistive index of the arciform arteries of both kidneys, which are indicative of the grade of obstruction.
    c) Advantages:
    • Absence of radiation.
    • No need for anaesthesia.
    d) Disadvantages:
    • Fails to identify stones in >40% of children.
    • Provides limited information on renal function.
  10. KUB radiography:
    a) Can help to identify stones and their radiopacity.
    b) Can facilitate follow-up.
    c) An alternative investigation (together with low-dose NCCT) if US will not provide the required information - Strong Recommendation.
  11. IVU:
    a) The radiation dose is comparable to that for VCUG (0.33 mSV).
    b) The need for contrast medium injection is a major drawback.
  12. NCCT:
    a) An alternative investigation (together with KUB) if US will not provide the required information - Strong Recommendation.
    b) Recent low-dose protocols significantly reduce radiation exposure.
    c) Only 5% of stones escape detection by NCCT.
    d) Sedation or anaesthesia is rarely needed with modern high-speed equipment.
  13. MRU:
    a) Cannot be used to detect urinary stones.
    b) Advantage: might provide anatomical information about
    • Collecting system.
    • Renal parenchymal morphology.
    • Site of obstruction / stenosis in the ureter.

X.7.5 Ureteral Stones:
  1. Uncomplicated ureteral stones ≤10 mm:
    a) Significant proportion of children will pass their stones spontaneously, thus avoiding the need for surgical intervention.
    b) Observation can be carried out under carefully controlled conditions, assuming no evidence of infection, the patient is able to hydrate orally, and pain can be adequately controlled.
    c) Offer observation with or without MET using α- blockers - weak Recommendation.
    d) Families should be aware that the probability of spontaneous passage is lower for children with stone approaching 1 cm in size.
    e) The role of MET with α-blockers in middle and proximal ureteral stones, similar to adults, is not well-defined.
    f) As in adults, the maximum time duration for a trial of MET is undefined, but it seems prudent to limit the interval to a maximum of 6 weeks from initial clinical presentation in order to avoid irreversible kidney injury.
  2. Ureteral stones unlikely to pass or stones that failed observation and/or MET:
    a) The benefits of treating the stone include alleviating symptoms, minimizing risk of infection, and preserving renal function by eliminating obstruction.
    b) Offer URS or SWL based on patient- specific anatomy and body habitus - Strong Recommendation.
    c) SFRs:
    • Higher for stones <10mm (87% for SWL and 95% for URS).
    • Lower for stones >10mm (73% for SWL and 78% for URS).
    d) While SWL is an acceptable option for ureteral stones, the poor visualization of the ureter (particularly the mid -ureter) with US-based lithotriptors may limit use of SWL in this setting.
    e) SWL may be preferable in certain pediatric populations, such as very small children, or other patients in whom ureteroscopic access may be challenging due to their anatomy (e.g., severe scoliosis, history of ureteral re-implantation).
  3. Except in cases of coexisting anatomic abnormalities, clinicians should not routinely perform open/ laparoscopic / robotic surgery for upper tract stones – weak recommendation.
    a) These approaches should be considered secondary or tertiary options for treatment of renal or ureteral stones since more conventional procedures, including SWL, URS, and PCNL, have high rates of success and lower risks of serious complications.
    b) There is very little evidence directly comparing the use of laparoscopic surgery or robotic-assisted laparoscopic surgery with more conventional treatments for stone disease in children.
    c) The primary exception is the presence of an anomaly associated with stones that may be treated at the time of reconstructive surgery. In such cases, open, laparoscopic, or robotic-assisted laparoscopic surgery is indicated to remove the stone(s) and repair the primary anatomic defect (UPJO with one or more renal or ureteral stones, others as ureterovesical junction obstruction and duplication anomalies with an obstructed ectopic ureter).
  4. SWL:
    a) Offer children with single ureteral stones <10 mm SWL if localisation is possible as first line option - Strong Recommendation.
    b) Well tolerated by children.
    c) Complication rates rising up to 15% in modern series, mostly in the form of ureteral obstruction secondary to steinstrasse formation.
    d) Improvements in modern (second and third generation) lithotripters, successful treatment using intravenous sedation, patient-controlled analgesia or no medication at all has been increasingly performed in a select population of older, co-operative children.
    e) Less likely to be successful for:
    • Stones >10 mm in diameter.
    • Impacted stones.
    • Calcium oxalate monohydrate or cystine stones.
    • Unfavourable anatomy.
    • In whom localisation is difficult.
    f) Overall SFR: 70-90% (higher for stones <10 mm than for stones >10 mm).
    g) Re-treatment rate: 4-50% (higher as the stone size increase).
    h) Auxiliary procedures: needed in 4-12.5% of cases.
  5. 5. Rigid / semi-regid URS:
    a) Recently is increasingly used in children with ureteral stones.
    b) A feasible alternative for stones not amenable to SWL - Strong Recommendation.
    c) Effective.
    d) SFR: 81-98%.
    e) Complication rate: 1.9-23%.
    f) Re-treatment rate: 6.3%-10%.
    g) Stenting before URS: similar to adults, clinicians should not routinely place a stent prior to URS – weak recommendation.
    • Access to the upper tract is readily possible in the majority of children.
    • If stone access is difficult or impossible, placement of a ureteral stent results in passive dilation of the ureter thus permitting access at the time of the next attempted URS.
    h) Stenting after URS: a strong predictor of re-treatment requiring anaesthesia in children.

X.7.6 Renal Stones:
  1. In asymptomatic and non-obstructing renal stones, clinicians may utilize active surveillance with periodic US – Weak recommendation.
    a) Monitor: increase in size of stone, number of stones, or silent obstruction.
    b) Families should be counseled about the need for regular follow-up.
    c) Evaluate the patient for underlying abnormalities that may predispose to further stone formation.
    d) Metabolic evaluation as the incidence of metabolic abnormalities is high in pediatric stone formers.
    • Toilet-trained children and adolescents: 24-hour urine collections are appropriate to assess urinary stone risk parameters.
    • Infants and non-toilet trained children: “spot” urine sample is used to screen for hypercalciuria (diagnostic limitations).
    • Infants and young children with hyperoxaluria should be screened for primary hyperoxaluria.
  2. Obtain a low-dose NCCT prior to performing PCNL - Strong Recommendation.
  3. In total renal stone burden ≤20mm:
    e) Offer SWL - Strong Recommendation.
    f) Very few high-quality comparative studies for SWL and URS or other modalities for treatment of renal stones in the pediatric population.
    g) SWL:
    • Success rate: high.
    • Stone-free rates: are high, 80-85% (overall) and 80% (lower pole stones).
    • Complication rates: low (8%-10%).
      • Serious complications are rare.
      • Little evidence of long-term sequelae.
    • SWL compared to mini-PCNL for lower pole renal stones 1-2 cm in size:
      • SWL has lower SFRs.
      • SWL has higher rates of secondary procedures.
      • SWL has less severe adverse events.
    h) FURS/RIRS:
    • A feasible alternative for renal stones ≤20 mm in all locations - Weak Recommendation.
    • Success rate: high.
    • Recent studies:
      • SFRs: 76-100%.
      • Re-treatment rate: 0-19%.
      • Complication rate: 0-28%.
    • Causes of failure:
      • Younger age.
      • Cystine composition.
      • Large stone diameter.
      • Lack of pre-stenting.
    • Lower calyx stones in the presence of unfavorable factors for SWL: may be an effective option but lacking high level of evidence to support strong recommendation.
    • Compared to PCNL in large and complex kidney stones:
      • Disadvantage: significantly lower SFR vs. PCNL (71% vs. 95%).
      • Advantage:
        • Less radiation exposure.
        • Lower complication rates.
        • Shorter hospital stay.
    • Compared to mini- or micro-PCNL:
      • Disadvantage: lower SFRs compared to mini- or micro- PCNL.
      • Advantage:
        • Shorter operative time.
        • Shorter fluoroscopy time.
        • Less hospitalisation time.
  4. In total renal stone burden >20mm:
    a) Offer children with renal pelvic or calyceal stones with a diameter >20 mm PCNL - Strong Recommendation.
    b) Both PCNL and SWL are acceptable treatment options – Weak Recommendation. SFR: high with both:
    • SWL: 73-83%. Placement of a ureteral stent or nephrostomy tube is recommended to prevent postoperative renal obstruction.
    • PCNL: vary by site. Recent large series approached 90% success rates.
    c) Factors taken into consideration when selecting which of these procedures:
    • Stone composition and attenuation.
    • Stone location.
    • Body habitus.
    • Collecting system anatomy.
    • Relation of the kidney to surrounding viscera.
    • Medical co-morbidity.
    • Parental preference.
    d) The utilization of smaller instruments for PCNL (mini-PCNL, micro-PCNL) may limit the risk of hemorrhage in this population.
    e) PCNL:
    • Indications:
      • Similar to those in adults.
      • Renal stones >2 cm.
      • Smaller stones resistant to SWL and URS.
    • SFRs: 71.4 - 95% after a single session.
    • Overall complication rate: 20%.
    • Increased blood loss if:
      • High degree of hydronephrosis.
      • Increased number of tracts.
      • Increased operative time.
      • Large tract size.
        • Child age and stone burden predispose to the use of larger instruments.
        • Miniaturisation of equipment increases the opportunity to perform tubeless PCNL in appropriately selected children, which can reduce the length of hospital stay and post-operative pain.
        • Studies showed that blood transfusion requirement is significantly less in all age groups when <20FG sheath is used.
    • Concerns have been raised regarding possible adverse effects of PCNL on the renal parenchyma of the developing child. However, focal damage is only reported in 5% of cases. Using pre- and post-PCNL DMSA scans, Cicekbilek et al. demonstrated that PCNL tracts between 12-24 Charrière in size did not cause significant harm to pediatric kidneys.

X.7.6.1 Open surgery:
1. With the advances in ESWL, PCNL and RIRS, very few cases require open surgery.

X.7.6.2 Laparoscopic / robot-assisted stone surgery:
  1. Laparoscopy and robotic-assisted laparoscopy have been utilized successfully in adults for treatment of calculi during the concomitant treatment of UPJO and in the primary treatment of staghorn calculi. Small series have only recently been described to be use these techniques in children.
  2. Laparoscopy for the management of pediatric renal and ureteric stones is a safe and effective procedure when specific indications are followed.
  3. SFRs of 100% were reported when:
    a) Laparoscopic pyelolithotomy if applied for:
    • A single stone, ≥1cm in size, located in an extra-renal pelvis.
    b) Laparoscopic ureterolithotomy if applied for:
    • Impacted ureteric stone ≥1.5 cm or ureteric stones refractory to SWL or URS.
  4. The available early experiences demonstrate that laparoscopic pyelolithotomy is feasible, safe, and efficacious as an alternative to open pyelolithotomy in children but needs further study.
  5. Because of their demanding technical nature, these procedures most likely be limited to cases who failed endourologic management in academic centers with abundant expertise in laparoscopy.

X.7.6.3 Special considerations on recurrence prevention:
  1. All pediatric stone formers need metabolic evaluation and recurrence prevention with respect to the detected stone type.
  2. Children are in the high-risk group for stone recurrence.

X.8 Special problems in stone removal
X.8.1 Calyceal diverticulum stones
  1. SWL:
    a) SFR is low, well-disintegrated stone material remains in the original position due to narrow calyceal neck.
    b) Although some patients experience a reduction or elimination of symptoms, they are at risk for:
    • Recurrence of symptoms.
    • New or residual stone growth.
  2. Endoscopic therapy:
    a) Flexible URS/RIRS, PNL, laparoscopic, robotic.
    b) Should be preferentially used - Strong Recommendation.
    c) SFR are higher.
    d) The chance for eradication of symptoms is greater.
    e) The approach also permits correction of the anatomic abnormality, with the chance for successful obliteration being highest with PCNL, laparoscopic, or robotic assisted surgery.
    f) The approach depend on:
    • Stone location.
    • Stone size.
    • Relation to surrounding structures.
    • Patient preference.

X.8.2 Horseshoe kidneys
  1. Can be treated in line with the options described above.
  2. Passage of fragments after SWL might be poor.
  3. Acceptable SFRs can be achieved with flexible URS/RIRS.

X.8.3 Stones in pelvic kidneys
  1. SWL, flexible URS/RIRS, PNL or laparoscopic surgery.
  2. Obese patients: flexible URS/RIRS, PNL or open surgery.

X.8.4 Stones formed in a continent reservoir:
  1. Each stone must be considered and treated individually.

X.8.5 Patients with UPJO:
  1. When outflow abnormality requires correction.
  2. Stone removal with open pyeloplasty.
  3. Stone removal with laparoscopic reconstructive surgery.
  4. PNL and percutaneous endopyelotomy (iatrogenic / recurrent UPJO).
  5. Flexible URS/RIRS and endopyelotomy:
    • In iatrogenic / recurrent UPJO.
    • Considered if falling of stone into pelvi-ureteral incision can be prevented
    • Using Ho:YAG laser for incision and lithotripsy or Acucise balloon catheter.

X.8.6 Non-obstructing calyceal stones:
  1. Asymptomatic patients:
    a) Offer active surveillance - Conditional Recommendation.
    b) Detection has increased due to the increased utilization of CT imaging.
    c) Follow-up imaging: to assess stone growth or new stone formation.
    d) Dietary modification may be considered.
    e) Medical therapy may be considered.
    f) Observation: appropriate.
    • Council the patient about risk of stone growth, passage, and pain.
    • Intervention if:
      • Associated infection.
      • Vocational reasons (e.g. airline pilots, military).
      • Poor access to contemporary medical care.
  2. Symptomatic patients: flank pain without another obvious etiology for pain.
    a) Offer stone treatment – Weak Recommendation.
    b) Inform patient of the possibility that the pain may not improve or resolve after the procedure.
  3. Symptomatic patients, stone < 10 mm.
    a) Offer SWL or flexible URS/RIRS - Strong Recommendation.
    b) SWL and flexible URS/RIRS: No statistically significant difference in SFRs.
    c) NCCT imaging parameters should be used for patient selection.
    d) SWL:
    • Patient-derived QoL measures are somewhat better.
    • Less successful results if:
      • Skin-to-stone distance > 9-10 cm.
      • Stone attenuation > 900-1000 HU.
    e) Flexible URS/RIRS:
    • Higher intraoperative complications.
    • Certain techniques employed to improve results:
      • Repositioning of stones into the upper pole before fragmentation.
      • Utilization of a ureteral access sheath.
      • Extraction of the generated fragments.
  4. Symptomatic patients, stone > 10 mm:
    a) Do not offer SWL as first-line therapy and use endoscopic approach]- Strong Recommendation.
    b) Endoscopic approaches: benefit over SWL
    • Better SFR with a moderate associated increase in risk.
    • Less affected by stone burden.
    c) PNL: superior single-treatment stone-free rate.
    • Should be considered the primary treatment for most cases.
    • Inform the patient:
      • It has the higher SFR but greater morbidity - Strong Recommendation.
      • Nature of the procedure.
      • Expected morbidity.
      • Potential complications.
    • PNL with smaller access sheaths (mini-PNL or micro-PNL) may allow similar outcomes with lower complication rates.
    d) Flexible URS/RIRS: inform the patient
    • Re-treatment rate is higher.
    • SFR is significantly lower.
    • Higher likelihood of clinical stone recurrence due to retained fragments.
    • Difficulties:
      • Stone may not be accessible:
        • Narrow lower pole infundibulum.
        • Acutely angled lower pole infundibulum.
        • Severe hydronephrosis.
        • Renal anomalies (horseshoe kidney).
      • Stone may not be possible to grasp and relocate necessitating laser treatment in the lower calyx with the ureteroscope maximally deflected with potential increasing the risk of laser fiber failure and ureteroscope damage.
  5. Symptomatic patients with non-lower pole renal stone burden < 20 mm
    a) Treatment options: SWL, flexible URS/RIRS, and PNL.
    b) Offer SWL or flexible URS/RIRS - Strong Recommendation.
    c) Treatment selection process must include a shared decision- making approach.
    d) SFR:
    • PNL: the least affected by stone size.
    • SWL:
      • Acceptable SFR.
      • SFR decline with increasing stone burden.
      • Less morbidity compared to PNL
    • Flexible URS/RIRS:
      • Acceptable SFR.
      • SFR decline with increasing stone burden.
      • Less morbidity compared to PNL.
      • Lower likelihood of repeat procedure compared to SWL.
      • The patient will become stone-free quicker than with SWL.

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