Editing AUA: Stone Surgery (2016) (section)

== Treatment of Ureteric Stones ==

=== UrologySchool.com summary ===
* '''<span style="color:#ff0000">Uncomplicated, < 10mm: observation +/- MET (recommended distal, optional mid or proximal location)</span>'''
* '''<span style="color:#ff0000">>10mm or failure of conservative management: URS vs. SWL</span>'''
** '''<span style="color:#ff0000">URS preferred for distal and mid</span>'''
** '''URS and SWL options for proximal'''

=== Symptomatic ===

==== Conservative treatment ====
* '''Observation'''
** '''<span style="color:#ff0000">Patients with uncomplicated [any location] ureteral stones <10 mm should be offered observation; </span>[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'''
**'''<span style="color:#ff0000">Patients with uncomplicated distal ureteral stones <10mm should be offered medical expulsive therapy (MET) with α-blockers </span>[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'''
**'''<span style="color:#ff0000">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
* '''<span style="color:#ff0000">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</span>'''
** '''<span style="color:#ff0000">Indications to proceed with surgical intervention (3):</span>'''
**# '''<span style="color:#ff0000">Pain</span>''': recurrent renal colic requiring repeated visits to the emergency department or hospital admission for parenteral analgesia
**# '''<span style="color:#ff0000">Worsening renal function</span>'''
**# '''<span style="color:#ff0000">Infection:</span>''' 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
* '''<span style="color:#ff0000">Approach: URS vs. SWL for ureteric calculi</span>'''
** '''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'''
** '''<span style="color:#ff0000">Stone location</span>'''
*** '''<span style="color:#ff0000">Mid or distal ureter:</span>'''
**** '''<span style="color:#ff0000">URS is the recommended first-line therapy</span>'''
**** '''<span style="color:#ff0000">SWL is second-line therapy</span>'''
***** '''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.
** '''<span style="color:#ff0000">Stone Composition</span>'''
*** '''<span style="color:#ff0000">URS recommended over SWL for suspected cystine or uric acid ureteral stones</span>'''
**** '''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'''
* '''<span style="color:#ff0000">Post-intervention</span>'''
** '''<span style="color:#ff0000">Following URS, stent placement is strongly recommended in (5):</span>'''
**# '''<span style="color:#ff0000">Ureteric injury during URS</span>'''
**# '''<span style="color:#ff0000">Evidence of ureteral stricture or other anatomical impediments to stone fragment clearance, such as ureteral wall edema</span>'''
**# '''<span style="color:#ff0000">Large stone burden (>1.5 cm)</span>'''
**# '''<span style="color:#ff0000">Anatomically or functionally solitary kidney or renal functional impairment</span>'''
**# '''<span style="color:#ff0000">Those in whom another ipsilateral URS is planned</span>'''
*** '''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.