AUA: Stone Surgery (2016)

See Original AUA Guideline

See 2019 AUA Evaluation and Medical Management of Stones Guideline Notes

See 2016 CUA Evaluation and Medical Management of Stones Guideline Notes

• This Guideline includes revisions of the previously published AUA Guidelines titled ‘Staghorn Calculi (2005)’ and ‘Ureteral Calculi (2007)’ and is expanded to incorporate the management of patients with non-staghorn renal stones

*****All of the information below is contained in the more comprehensive

• Surgical Modalities for Management of Upper Urinary Tract Calculi Chapter Notes
• Treatment Selection for Upper Urinary Tract Calculi Chapter Notes
• Stones During Pregnancy Chapter Notes
• NOT included elsewhere is Pediatric Stone Disease (see below)

*****

Investigations Prior to Treatment

UrologySchool.com Summary

• History and Physical Exam
• Laboratory:
  • Mandatory (1): urinalysis +/- culture
  • Certain situations (4): serum electrolytes, serum creatinine, CBC, coagulation profile
• Imaging
  • Non-contrast CT
    • Should be obtained prior to PCNL
    • Can help select between SWL vs. URS (decision should not be based on US)
  • Certain situations: functional imaging, other contrast enhanced studies

Laboratory

• Urinalysis +/- culture
  • Required prior to intervention
  • In patients with clinical or laboratory signs of infection, urine culture should be obtained
    • If the culture demonstrates infection, appropriate antibiotics should be prescribed based on sensitivity
    • There can be discordance between preoperative voided urine cultures or those from indwelling urethral catheters compared to urine proximal to an obstructing stone.
      • Intraoperative urine cultures should be obtained, if technically feasible, from urine proximal to the stone if infected urine is suspected at the time of intervention.
    • Additionally stone cultures may be obtained, especially in cases of suspected infection-related stones, in order to help guide postoperative therapy.
      • There is also potential discordance between stone cultures and preoperative voided urine cultures
• Serum electrolytes and creatinine
  • Should be obtained if there is suspicion of reduced renal function
    • Reduced renal function is suspected in those with hydronephrosis, parenchymal thinning or co-morbid conditions associated with renal dysfunction and electrolyte disturbances
• CBC and platelet count
  • Should be obtained for patients:
    1. Undergoing procedures where there is a significant risk of hemorrhage (e.g. PCNL)
    2. With symptoms suggesting anemia, thrombocytopenia, or infection
• Coagulation studies
  • In the absence of clinical indications (e.g., systemic anticoagulation, relevant hepatic dysfunction, hematologic disease or bleeding disorders, history suggestive of a coagulation disorder) coagulation studies should not be routinely obtained prior to surgical management of urinary stone disease

Imaging

• Non-contrast CT
  • CT protocols have been developed and evaluated utilizing radiation doses approximating those of plain film radiography.
  • Should be obtained prior to performing PCNL
    • Defines stone burden and distribution
    • Provides information regarding collecting system anatomy, position of peri-renal structures and relevant anatomic variants
    • May be used to predict stone composition
    • May be used to predict operative outcomes
  • May be used to help select the best candidate for SWL vs. URS
    • Ultrasound alone to select SWL vs. URS should be discouraged
      • Disadvantages of US:
        • Provides no information on stone density
        • Inaccurate in determination of stone size
          • US will correlate approximately 2/3 of the time with the stone size determined on CT scan.
            • US will overestimate the size of 1/3 of stones < 10 mm, and underestimate the size of 1/3 of stone, > 10 mm.
            • KUB underestimates > 90% stones > 10 mm due in part to its inability to measure in three dimensions
    • Factors associated worse SWL outcomes:
      • Renal stone attenuation >900-1000 Hounsfield units
      • Skin-to-stone distance >10cm
• Functional imaging study (DTPA or MAG‐3)
  • May be obtained if clinically significant loss of renal function in the involved kidney(s) is suspected
• Additional contrast imaging may be obtained if further definition of the anatomy is needed
  • Situations in which complex urinary tract anatomy may require further imaging include:
    • Ectopic kidneys (e.g., horseshoe kidney, pelvic kidney, cross-fused ectopia)
    • Other congenital kidney conditions (e.g., UPJ obstruction, duplicated collecting system, caliceal diverticulum, ureteral stricture, megaureter, ureterocele),
    • Renal transplant grafts
    • Kidneys with prior surgery
    • Complex stone anatomy/conditions (e.g., staghorn stones, nephrocalcinosis).
  • Further imaging may be required in certain patients (e.g., neurologic disorders, including spinal dysraphism; unusual body habitus; presence of urinary diversion or prior kidney/ureteral surgery)
  • CT and IVP are the most useful IV contrast studies
    • MR urography can be useful in defining anatomy during pregnancy (without contrast) and in the setting of IV contrast allergy, although stones are typically not well visualized directly with MR imaging
    • Contrast imaging studies can also include retrograde or antegrade pyelography

Treatment of Ureteric Stones

UrologySchool.com summary

• Uncomplicated, < 10mm: observation +/- MET (recommended distal, optional mid or proximal location)
• >10mm or failure of conservative management: URS vs. SWL
  • URS preferred for distal and mid
  • URS and SWL options for proximal

Symptomatic

Conservative treatment

• Observation
  • Patients with uncomplicated [any location] ureteral stones <10 mm should be offered observation; [different than 2015 CUA Ureteric Calculi guidelines which suggest intervention for stone >5mm]
    • A trial of spontaneous passage is reasonable in patients amenable to conservative therapy with distal ureteral stones <10 mm in whom pain is well controlled and there are no signs of infection or high-grade obstruction.
      • The smaller the stone and the more distally in the ureter the stone is located, the greater the likelihood of spontaneous passage
      • The control arms of RCTs evaluating tamsulosin as MET show that ≈50% of patients with distal ureteral calculi <10 mm in size will spontaneously pass their stones
• Medical expulsive therapy
  • Patients with uncomplicated distal ureteral stones <10mm should be offered medical expulsive therapy (MET) with α-blockers [same as 2015 CUA Ureteric Calculi Guidelines]
    • Ureteral contractility is mediated by both α and β adrenoreceptors in the ureteral wall. Stimulation of α1-receptors promotes contraction of ureteral smooth muscle, leading to more vigorous and frequent peristalsis. α1-antagonists have the potential to inhibit ureteral spasm and uncontrolled contraction, theoretically reducing pain and promoting spontaneous stone passage.
      • In patients with <10 mm distal ureteral stones, spontaneous stone passage rates improves with α-blockers compared to no treatment (ARR: 23%, 77% α-blockers vs. 54% placebo or no treatment)
        • A recent RCT (SUSPEND trial) from the United Kingdom compared tamsulosin (0.4 mg daily), nifedipine (30 mg daily) and placebo (1:1:1) in patients with ≤10 mm ureteral calculi. Unlike most MET trials, the primary outcome in this trial was absence of need for additional intervention at 4 weeks rather than radiographic evidence of stone passage. There was no difference between groups for the primary outcome. The results of this trial were not incorporated into this Panel’s meta-analysis.
        • Pickard, Robert, et al. "Medical expulsive therapy in adults with ureteric colic: a multicentre, randomised, placebo-controlled trial." The Lancet 386.9991 (2015): 341-349.
    • Calcium channel blockers
      • Suppress smooth muscle contraction by inhibiting the influx of extracellular calcium into smooth muscle cells
      • Insufficient supporting data for the utilization of this agent for MET.
    • Patients should be informed that medications for MET are prescribed off-label
  • MET can be considered an option in patients with an uncomplicated middle or proximal ureteric calculi <10mm; [2015 CUA Ureteric Calculi Guidelines do not explicitly describe role of MET in these locations]
    • No benefit of therapy based on the few α-blocker trials that included patients with middle and proximal ureteral calculi; therefore, use of MET for stones in the middle and proximal ureter could not be specifically endorsed. However, because of the low side effect profile of α-blockers and the demonstrated efficacy of α-blockers in patients with <10 mm stones in any location of the ureter, a trial of α-blockers in a patient with middle or proximal ureteric calculi <10mm, can be considered an option, despite the lack of demonstrable benefit
• In most patients, definitive stone treatment should be offered if observation +/- MET is not successful after 4-6 weeks and/or the patient/clinician decide to intervene sooner
  • Indications to proceed with surgical intervention (3):
    1. Pain: recurrent renal colic requiring repeated visits to the emergency department or hospital admission for parenteral analgesia
    2. Worsening renal function
    3. Infection: evidence of urinary tract sepsis
  • A 6-week interval is recommended to reduce the potential for permanent damage. A previous study has also indicated that most stones destined to pass spontaneously will do so within 6 weeks. As such, there seems little benefit in continuing MET beyond this time interval.

Intervention

• In patients with obstructing stones and suspected infection, clinicians must urgently drain the collecting system with a stent or nephrostomy tube and delay stone treatment
  • Definitive management of the stone should not be undertaken until sepsis has resolved and the infection has been treated with an appropriate course of antibiotic therapy.
• Clinicians should offer reimaging to patients prior to surgery if passage of stones is suspected or if stone movement will change management
  • ≈10% risk of negative URS for ureteral stones < 4 mm in a distal ureteral location
  • Other factors that influence the decision to re-image a patient include time interval since prior imaging, pain, and presence of obstruction/hydronephrosis
  • Reimaging should focus on the region of interest and limit radiation exposure to uninvolved regions
• Approach: URS vs. SWL for ureteric calculi
  • The patient should be informed of the advantages and disadvantages of SWL and URS (anesthesia requirements, stone-free rates, need for additional procedures, and associated complications of each procedure)
    • SWL is the procedure with the least morbidity and lowest complication rate
      • 2012 Cochrane Review comparing SWL and URS identified 7 RCTs significantly lower complication rate for SWL compared to URS
        • Ureteral perforation occurs significantly more frequently during URS than SWL
        • No difference with regard to UTI, sepsis, ureteral stricture, or ureteral avulsion
    • URS has a greater stone-free rate in a single procedure
      • Stone-free rates are higher for URS than SWL for all ureteral stones EXCEPT proximal ureteral stones >10 mm in size where stone-free rates are comparable
    • Patients should be informed about the possible need for stent placement after URS, and less commonly, after SWL, because this may influence their decisions
  • Stone location
    • Mid or distal ureter:
      • URS is the recommended first-line therapy
      • SWL is second-line therapy
        • For women of child-bearing age with mid or distal ureteral calculi, URS is preferred, as the effects of shock wave energy on the ovary have not been completely elucidated
    • [Proximal ureter:]
      • [URS and SWL are options]
        • For proximal ureteric stones < 10mm, stone-free rates with URS are superior than SWL
        • For proximal ureteric stones >10mm, stone-free rates are equivalanet
        • Therefore, the recommendation for first-line use of URS was not extended to proximal ureteral stones.
    • Alternative treatment options, such as open or laparoscopic ureterolithotomy, or antegrade URS via a percutaneous approach, are not preferred over SWL because of greater invasiveness.
  • Stone Composition
    • URS recommended over SWL for suspected cystine or uric acid ureteral stones
      • Cystine stones are often only faintly radio-opaque and pure uric acid stones are typically radiolucent. Therefore, stone targeting with fluoroscopy may be problematic for SWL. Furthermore, cystine stones are typically resistant to SWL fragmentation
  • 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.

Ureteral stenting

• Pre-intervention
  • Routine stent placement is not recommended prior to URS or SWL for ureteric calculi
    • In SWL, stenting prior to treatment has not been shown to improve stone-free rates
      • 2019 AUA Update on Pediatric Urolithiasis: "When [SWL]used for renal stones >20 mm, a ureteral stent should be left in place to aid in stone passage and avoid steinstrasse."
    • In URS, stenting prior to treatment may improve stone-free rates and reduce operative times but does not override the added care costs and negative impact on quality of life associated with stents
• Post-intervention
  • Following URS, stent placement is strongly recommended in (5):
    1. Ureteric injury during URS
    2. Evidence of ureteral stricture or other anatomical impediments to stone fragment clearance, such as ureteral wall edema
    3. Large stone burden (>1.5 cm)
    4. Anatomically or functionally solitary kidney or renal functional impairment
    5. Those in whom another ipsilateral URS is planned
    • Ureteral stenting may be omitted in patients without any of the features above; stent placement after uncomplicated URS has also been shown in randomized trials to be unnecessary
    • The duration of ureteral stenting post-operatively should be minimized in order to reduce stent-related morbidity. In general, 3-7 days of stenting is recommended following routine, uncomplicated ureteroscopic stone intervention
• α-blockers and anticholinergics therapy may be offered to reduce stent discomfort
  • Patients should be counseled about the possibility of post-operative stent discomfort
  • Other medications that can be used to alleviate stent discomfort include bladder analgesics for dysuria, non-steroidal anti-inflammatory agents, and narcotic analgesics.

URS for ureteral stones

• Clinicians performing URS for proximal ureteral stones should have a flexible ureteroscope available
  • Semi-rigid URS above the level of the iliac vessels can cause additional torque on the ureteroscope, placing the ureteroscope itself at risk for damage.
• Clinicians should not utilize EHL as the first-line modality for intra-ureteral lithotripsy
  • The holmium laser can be activated 0.5 mm from the urothelial surface without risk of injury.
  • Due to a larger working area, EHL can safely be used in the kidney during PCNL, but the risk of perforation using this technology is still higher than other modalities. Therefore, care should be taken to avoid activation of the probe near the urothelial surface.

Treatment of Renal Stones

UrologySchool.com summary

• Asymptomatic, non-obstructing caliceal stones: active surveillance
• Symptomatic, total stone burden < 20mm
  • Non-lower pole: either SWL or URS are preferred over PCNL
  • Lower pole:
    • ≤10mm: SWL or URS
    • 10-20mm: PCNL (first-line) or URS (no SWL)
• Symptomatic, total stone burden >20mm: PCNL (first-line) or URS (option) (no SWL)

Asymptomatic, non-obstructing caliceal stones

• Active surveillance may be offered
  • Observation of asymptomatic, non-obstructing caliceal stones is appropriate as long as the patient is counseled about the risk of stone growth, passage, and pain.
  • There is conflicting data on the natural history of asymptomatic renal stones
    • ≈50% of asymptomatic stones will progress, a much smaller percentage will require surgical intervention.
      • Lower pole stone location and isolated stone ≥ 4 mm were associated with a higher likelihood of failing observation.
  • Treatment of asymptomatic, non-obstructing caliceal stones should be considered in:
    1. Cases of associated infection
    2. Vocational reasons (e.g. airline pilots, military)
    3. Poor access to medical care
  • If observation is chosen for asymptomatic, non-obstructing caliceal stones, follow-up imaging studies to assess for stone growth or new stone formation is recommended. Dietary modifications and medical therapy may be considered, especially if new stone formation occurs

Symptomatic

• Total stone burden ≤20mm
  • Non-lower pole stone
    • Recommended options: SWL or URS
      • Treatment options for patients with a <20 mm non-lower pole renal stone burden include SWL, URS, and PCNL. Of these, PCNL stone-free rates are the least affected by stone size, while stone-free rates of both SWL and URS decline with increasing stone burden. However, for stone burdens <20mm, stone-free rates of both URS and SWL are acceptable and have less morbidity compared to PCNL.
  • Lower pole stone
    • ≤ 10 mm
      • Recommended options: SWL or URS
        • An RCT found that there was no significant difference between the stone-free rates with URS vs. SWL. Intraoperative complications were higher with URS, and patient-derived QoL measures were better with SWL in this trial.
        • CT imaging parameters should be used for patient selection.
    • > 10mm
      • Recommended options: PCNL (preferred) or URS; SWL not recommended
        • Clinicians should inform patients with lower pole stones >10 mm in size that PCNL has a higher stone-free rate but greater morbidity [than URS].
        • PCNL should be considered the primary treatment
• Stone burden > 20 mm
  • Recommended options: PCNL (first-line) or URS (option); SWL not recommended as first-line
    • Significantly reduced stone-free rates and increased need for multiple treatments for SWL compared to PCNL for patients with a total renal stone burden > 20 mm
      • Success of SWL is dependent on several other factors, including obesity, skin-to-stone distance, collecting system anatomy, stone composition and stone density/attenuation, which could also contribute to lower stone-free rates
      • The benefit of a higher stone-free rate must be weighed against the increased invasiveness and risk of complications for PCNL compared to URS or SWL.
        • 15% overall complication rate with PNCL, majority categorized as Clavien Grade I. Bleeding necessitating blood transfusion (7%) is the most common complication
      • The risk of ureteral obstruction from stone fragments (steinstrasse) increases
• Staghorn calculi
  • PCNL is the first-line treatment

Open/ laparoscopic /robotic surgery

• Should not be offered as first-line therapy to most patients with stones.
  • Exceptions include:
    • Rare cases of anatomic abnormalities with large or complex stones
    • Requiring concomitant reconstruction, such as those with concomitant UPJ obstruction or ureteral stricture.

Nephrectomy

• In patients requiring treatment, nephrectomy may be performed when the involved kidney has negligible function

• Observation may be appropriate for some asymptomatic patients. However, poorly functioning kidneys can often be a source of persistent infection, pain, and pyelonephritis. In these cases, nephrectomy may be the best treatment option to relieve symptoms and prevent systemic complications, such as sepsis and xanthogranulomatous pyelonephritis.
• When considering nephrectomy for the poorly functioning kidney, overall renal function and the condition of the kidney on the contralateral side should be considered.
• Nephrectomy should be avoided, if possible, in pregnant patients until after they deliver.

PCNL

• Relative contraindications to PCNL (2):
  1. Use of anti-coagulation or anti-platelet therapy that cannot be discontinued
  2. Anatomic derangements (e.g. contractures, flexion deformities) that may preclude positioning for PCNL
  • In patients not considered candidates for PCNL, clinicians may offer staged URS
• Clinicians must use normal saline irrigation for PCNL and URS
• A safety guide wire should be used for most endoscopic (URS or PCNL) procedures
  • Situations where a safety guidewire cannot be placed, may not be necessary, or may even be harmful (2):
    1. Severely impacted ureteral stones where even a hydrophilic guidewire cannot safely be negotiated proximal to the stone.
    2. When a ureteral access sheath is being used to facilitate treatment of intra-renal stones with the flexible ureteroscope.
• Flexible nephroscopy should be a routine part of standard PCNL
  • In an RCT, stone-free rate was higher in patients that underwent concomitant flexible endoscopy with rigid nephroscopy during PCNL, compared to without concomitant flexible nephroscopy, 92.5% vs 70%.
• In patients undergoing uncomplicated PCNL who are presumed stone-free, placement of a nephrostomy tube is optional
  • Purpose of the nephrostomy tube following PCNL (4):
    1. Aid in healing of the nephrostomy tract
    2. Promote hemostasis
    3. Prevent extravasation of urine
    4. Allow for re-entry into the collecting system should a secondary procedure be necessary
  • In the appropriately selected patient, "tubeless" PCNL can result in similar stone-free and complication rates as standard PCNL.
    • “Tubeless” PCNL is a term used to describe the scenario when no nephrostomy tube is inserted at the end of the procedure. Renal drainage can be established with an indwelling or externalized stent, or the patient can be left without a stent.
    • Indwelling nephrostomy tubes following PCNL is associated with increased postoperative pain with greater narcotic requirements and increased length of hospitalization compared to tubeless PCNL.
    • The tubeless approach should not be undertaken if there is active hemorrhage or it is likely that another PCNL will be needed to remove residual stones

SWL

• α-blockers may be prescribed post-SWL to improve stone-free rate (CUA also recommends α-blockers post-SWL )
• If initial SWL fails, clinicians should offer endoscopic therapy as the next treatment option.
  • Those who have had partial fragmentation and clearance may be considered for repeat SWL while those with no fragmentation and/or clearance may be selected specifically for endoscopic intervention.
• SWL should not be used in the patient with anatomic or functional obstruction of the collecting system or ureter distal to the stone.

Other considerations

• Uncorrected bleeding or patients who require continuous anticoagulation/antiplatelet therapy diatheses:
  • URS should be used as first-line therapy in most patients who require stone intervention
• Symptomatic caliceal diverticular stones
  • Endoscopic therapy (URS, PCNL, laparoscopic, robotic) should be preferentially utilized i.e. avoid SWL
• Staghorn stones
  • Should be removed if attendant comorbidities do not preclude treatment.
    • Risks of untreated staghorn stones:
      • Deterioration of renal function, including loss of the involved kidney, end stage renal disease
      • Infectious complications
      • Mortality
    • Medical therapy and supportive care are considerations for those not thought to be operative candidates.
• When residual fragments are present, clinicians should offer patients endoscopic (URS or PCNL) procedures to render the patients stone-free, especially if infection stones are suspected.
  • Untreated struvite stones have a high likelihood of stone growth and recurrent infections. These “infection stones” may grow to a large size, often filling a large portion or the entire renal collecting system (i.e., staghorn calculus). Such stones may cause persistent infection and chronic obstruction, ultimately leading to severe renal damage with the possibility of life-threatening sepsis. Removal of suspected infection stones or infected stone fragments may significantly limit the possibility of further stone growth, recurrent UTI, or renal damage. An endoscopic approach, either URS or PCNL, offers the best chance of complete removal of infection stones.
  • Non-surgical treatment with antibiotics, urease inhibitors, and other supportive measures only is not considered a viable alternative except in patients otherwise too ill to tolerate stone removal or when the residual fragments cannot be safely retrieved
• Stone treatment may be offered for patients with symptomatic (flank pain), non-obstructing, caliceal stones without another obvious etiology for pain.
  • Whether non-obstructing caliceal stones can be a source of pain is controversial. Since there are published reports of eradication of flank pain with stone removal in this setting, the Panel feels that patients with pain and non-obstructing caliceal stones, without another obvious source of their pain, may be offered surgical intervention for stone treatment. The patient must be informed of the possibility that the pain may not improve or resolve after the procedure.
• Antimicrobial prophylaxis
  • In the absence of a UTI, SWL does not require antimicrobial prophylaxis as no invasive procedure is performed
  • Antibiotic prophylaxis is recommended for ureteroscopic stone removal and PCNL and is based primarily on prior urine culture results, the local antibiogram, and in consultation with the current Best Practice Policy Statement on Antibiotic Prophylaxis.
    • A single dose (oral or IV) of an antibiotic that covers gram positive and negative uropathogens is recommended is administered within 60 minutes of the procedure (and re-dosed during the procedure if the case length necessitates)
    • 2019 AUA Antimicrobial Prophylaxis Guidelines:
      • Percutaneous renal surgery; e.g. PCNL; clean-contaminated: 1st/2nd gen. Cephalosporin, aminoglycoside (Aztreonam¥) + Metronidazole, or Clindamycin
      • Ureteroscopy, all indications; clean-contaminated: TMP-SMX, 1st/2nd gen. Cephalosporin
    • The presence of unsuspected bacteria within stones may be one of the underlying causes for infectious complications after PCNL. It has been reported that many patients with negative voided urine cultures before PCNL have positive kidney stone cultures.
• If purulent urine is encountered during endoscopic intervention, stone removal procedures should be aborted, appropriate drainage should be established, antibiotics continued, and a urine culture should be obtained.
• Stone material should be sent for analysis
  • An exception would be a patient who has had multiple recurrent stones that have been documented to be of similar stone composition and there is no clinical or radiographic evidence that stone composition has changed.

Pediatrics

• Overall, more generous use of SWL

Ureteral stones

• Uncomplicated ureteral stones ≤10 mm
  • Observation +/- MET using α-blockers should be offered [similar to adults]
  • URS or SWL for ureteral stones who are unlikely to pass the stones or who failed observation and/or MET, based on patient-specific anatomy and body habitus [different than adults where URS preferred for distal or mid ureteric stones]
• Routine stenting prior to URS for ureteral stones is not recommended [similar to adults]

Renal stones

• Active surveillance with periodic ultrasonography may be utilized in pediatric patients with asymptomatic and non-obstructing renal stones
• Total renal stone burden <20mm
  • Options: SWL or URS [different than adults where stone location is important; in adults, for lower pole stone >10mm, SWL is not recommended, all other stones <20mm can be treated with URS or SWL]
• Total renal stone burden >20mm
  • Options: both PCNL and SWL are acceptable treatment options [different than adults, no role for SWL for total renal stone burden >20mm]
    • A non-contrast, low-dose CT scan should be obtained prior to PCNL [similar to adults]
    • If SWL performed for total stone burden >20mm, placement of a ureteral stent or nephrostomy tube is recommended to prevent postoperative renal obstruction. [different than adults, no indication for routine stent with SWL]

Open/laparoscopic/robotic surgery

• Except in cases of coexisting anatomic abnormalities, open/laparoscopic/robotic surgery for upper tract stones should not be routinely performed.

• Series in adults have suggested that laparoscopic approaches may compare favorably to percutaneous techniques for large or staghorn renal stones, but in children, 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.
• The primary exception to this statement is in the pediatric patient with one or more renal or ureteral stones and a co-existing anatomic anomaly, such as UPJ obstruction, UVJ obstruction and duplication anomalies with an obstructed ectopic ureter. In such cases, open, laparoscopic, or robotic-assisted laparoscopic surgery is indicated to remove the stone(s) and repair the primary anatomic defect.

Pregnant women

• In pregnant patients, pharmacological and surgical intervention should be coordinated with the obstetrician
• Pregnant patients with ureteral stone(s) and well controlled symptoms should undergo observation as first-line therapy
  • A stone event in pregnancy is associated with an increased risk of maternal and fetal morbidity, so patients should be followed closely for recurrent or persistent symptoms.
  • Should MET be considered for the pregnant patient, patient should be counseled that MET has not been investigated in the pregnant population, and the medication is being used for an “off-label” purpose.
  • NSAIDs (e.g., ketorolac) are contraindicated in pregnancy
• URS may be performed in pregnant patients with ureteral stones who fail observation. Ureteral stent and nephrostomy tube are alternative options with frequent stent or tube changes usually being necessary.

References

• Assimos, Dean, et al. "Surgical management of stones: American urological association/endourological society guideline, PART I." The Journal of urology 196.4 (2016): 1153-1160.