AUA: Stone Surgery (2016): Difference between revisions

== Investigations prior to treatment ==

** '''Mandatory: urinalysis +/- culture'''

** '''Certain situations: serum electrolytes, serum creatining, CBC, coagulation profile'''

* '''Conservative treatment (observation, medical expulsive therapy)'''

** '''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

*** '''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):'''

***# '''Pain''': recurrent renal colic requiring repeated visits to the emergency department or hospital admission for parenteral analgesia

***# '''Worsening renal function'''

***# '''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):'''

***# '''Ureteric injury during URS'''

***# '''Evidence of ureteral stricture or other anatomical impediments to stone fragment clearance, such as ureteral wall edema'''

***# '''Large stone burden (>1.5 cm)'''

***# '''Anatomically or functionally solitary kidney or renal functional impairment'''

***# '''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

** '''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.

*** 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'''

* '''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.

*'''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'''

*** '''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:'''

***# '''Cases of associated infection'''

***# '''Vocational reasons (e.g. airline pilots, military)'''

***# '''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

** '''Total stone burden ≤20mm'''

*** '''Non-lower pole stone'''

****** 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.'''

*'''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.'''

* '''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]

** 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.