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Summary AUA Guidelines

Age	Size	Location	MET	Surgery
Adult	< 10mm	proximal ureter	attempt for 4-6 weeks	flexible URS ESWL (2nd line)
		mid-ureter
		distal ureter	50% spontaneous passage 77% passage with a-blockers
	> 10mm	proximal ureter	no benefit
		mid-ureter
		distal ureter
	< 20mm	non-lower pole total burden	no benefit	URS/ESWL: SFR decreases with increased stone size PCNL: no effect of stone size
	> 20mm	total renal burden		PCNL: first line, SFR 70-94% URS: SFR 75%, better if staged, less complications ESWL: SFR 19-57%, higher sepsis rate
	< 10mm	lower pole burden		ESWL/URS: equivalent SFR
	> 10mm			PCNL: highest SFR, highest risk URS/ESWL: 2nd line
	residual stones		possible benefit if small/obstructing	Treatment may be required if fragments > 2mm and near renal pelvis or ureter infection stones require treatment
	renal stones w/ pain but no obstruction		no benefit	Treat if no other source of pain, but counsel that pain may not improve after stone removal ESWL: SFR 0-25% (not recommended)
	asymptomatic renal stones		no benefit	Treatment not required 30-46% chance of stone growth 13%-49% chance of symptomatic stone event 7-26% need for intervention Treat if likely infectious, high risk profession, or poor follow-up risk
Pediatric	ureteral stones		benefit if < 10mm	URS: SFR 95% (< 10mm), 78% (> 10mm) ESWL: SFR 87% (< 10mm), 73% (> 10mm) prestenting not required
	renal stones		no benefit	URS: recommended if < 20mm (SFR 80-85%) PCNL: recommended if > 20mm (SFR ~90%) ESWL: SFR 80-85% (< 20mm), 73-83% (> 20mm)
Pregnant	any location		Okay: a-blockers, narcotics Not okay: NSAIDs	Situation dependent Max XRT dose 50 mGy

Ureteroscopy (URS)

Tips for success

• Safety wire: obtain and maintain renal access in case stenting needed
• Dust/Fragment: risks/benefits to both, can dust outside of stone and fragment harder inner core
• Trendelenberg positioning: consider to maneuver stones to upper pole, will help flush out lower pole dust
• Injecting adjuncts: consider injecting blood to create clot to stick to stone dust for removal, consider injecting 50% lidocaine jelly + 50% saline to loosen impacted ureteral stone
• Access sheath: improves irrigation flow and ability to remove multiple fragments, almost always place stent if sheath is used
• Preoperative tamsulosin: multiple studies have shown it improves chances of 16Fr sheath placement and decreases ureteral injury risk
• Postop pain management: NSAIDs have been shown to be as efficacious as narcotics
• Stentless criteria: no ureteral injury stricture or edema, stone burden small/moderate, no significant residual fragments, normal overall renal function, normal contralateral kidney, no anatomic variation, no subsequent ureteroscopy planned
• Dangler: no increased UTI risk, recommend pulling in shower while urinating

Complications

• Pain control: increased risk for ED bounceback (compared to stentless), but no increased risk for hospitalization, 0.5% non-stented patients require urgent stenting (from Hiller 2021)
• Perforation: 0-4%, stop procedure and place stent
• Stricture: 3-6%, always obtain postoperative imaging to assess for obstruction
• Lost stone: do not attempt to remove, place stent and give antibiotics
• Avulsion: < 0.06-0.5%, proximal portion at highest risk, do not perform blind basketing, place PCN and perform delayed repair, extensive injuries require ileal ureter or autotransplantation

Percutaneous Nephrolithotomy (PCNL)

Tips for success

• Preoperative antibiotics: should receive 7 days abx even with negative culture to decrease sepsis risk from stone colonization (higher risk if less than 7 days, per Sur 2021)
• Access location: upper pole access risks pleural/lung injury, lower pole access may make ureteral access more difficult due to angle
• Fluoroscopic access: eye of the needle or triangulation techniques, no clear benefit to one over the other
• Dilate tract either with balloon or sequential dilators, do not dilate past calyx (can rupture infundibulum)
• No proven benefit for tract sealant
• Nephrostomy tube: not always required, but indicated if residual stone, infection/sepsis, significant bleeding, extravasation, ureteral obstruction, solitary kidney, planned second-look, or planned instillation of chemical irrigation

Complications and contraindications

• Contraindications: untreated UTI, coagulopathy, inability to obtain access, pregnancy, renal malignancy
• Complications: overall 20-30%, fever 15-30%, transfusion 5-10%, sepsis 0.5-2.5%, angioembolization < 1%, thoracic complications < 3%, organ injury < 1%, death < 0.3%
• Avoiding vascular injury during access: avoid renal pelvis (no overlying parenchyma to tamponade bleeding), avoid infundibulum (higher concentration of vessels)
• Intraoperative bleeding: stop surgery, plan dilating balloon to tamponade, place large nephrostomy tube, consider clamping nephrostomy tube to form clot, may require embolization
• Extravasation: diagnose if large descrepancy in input/output, place nephrostomy tube and stop surgery, remove once nephrostogram shows no extravasation
• Pleural injury: higher risk with supracostal access, check CXR at end of case or in PACU, place chest tube and place to suction, switch to water seal and remove if no development of hydro/pneumothorax
• Colonic injury: use PCN as colonic drainage, place new PCN or stent for GU drainage, make NPO and slowly advance diet, perform contrast imaging (colonogram) after 7 days to assess for persistent fistula prior to removing tubes, intraperitoneal injury may require operative management to prevent peritonitis
• Solid organ injury: liver can leave PCN in place to tamponade but occasionally may require surgical repair, gallbladder/spleen usually require surgical removal of affected organ
• Duodenal injury: perforation of renal pelvis into duodenum, place nephrostomy tube and NGT for 2wks, then perform nephrostogram and upper GI study, remove tubes if no fistula present

Extracorporeal Shock Wave Lithotripsy (ESWL)

Tips for success

• Density: Hounsfield units < 900-1000 respond best
• Skin/Stone distance: < 10cm has best success
• Pre-stenting: no improvement in stone passage
• a-blockers: increase stone-free rates, decrease time to stone passage
• Antibiotics: not required
• Contraindications: pregnancy, coagulopathy, untreated UTI, renal/aortic aneurysm, upper tract obstruction, inability to target stone
• Complicating factors: stone type (CaOx, cystine), anatomic abnormalities, difficult lower pole anatomy, patient immobility, impacted stone
• Intraoperative imaging with fluoroscopy, ultrasound, or both
• Fragmentation mechanics buzzwords: spall fracture, squeezing, shear stress, superfocusing, acoustic cavitation, dynamic fatigue

Complications and contraindications

• Complications: hematuria (common), hematoma (1-20%), UTI (5%), sepsis (< 3%), but no evidence for long-term effects on HTN, CKD, fertility
• Intraoperative arrhythmia: more common R side and w/ renal stones, reduce risk by gating shock to R wave, otherwise stop procedure
• Steinstrasse: occurs in ~10% (increased risk with greater burden), may require stent or PCN to relieve obstruction, rarely requires ureteroscopy to clear fragments