What is the appropriate management for a patient with a 2 mm renal stone in the mid calyces of the right kidney and a 7 mm ureteral stone in the proximal right ureter, associated with mild hydroureteronephrosis, indicated for Extracorporeal Shock Wave Lithotripsy (ESWL)?

From the Guidelines

Extracorporeal shock wave lithotripsy (ESWL) is the recommended treatment for the 7 mm stone located in the proximal right ureter at the L3 vertebral level, as it has the least morbidity and lowest complication rate, although ureteroscopy (URS) has a higher stone-free rate in a single procedure 1. The 7 mm stone in the proximal right ureter has a high density of 1375 Hounsfield Units (HU) and is causing mild hydroureteronephrosis, indicating partial urinary obstruction.

Key Considerations

• ESWL is an appropriate treatment choice for this stone due to its size and location, with a success rate of 72% compared to 90% for URS 1.
• The smaller 2 mm stone in the mid calyces of the right kidney with 112 HU density can likely be managed conservatively with hydration and medical expulsive therapy, as stones smaller than 5 mm typically pass spontaneously.
• During ESWL, focused shock waves will fragment the larger ureteral stone, allowing the pieces to pass naturally.
• The procedure is minimally invasive and usually performed as an outpatient treatment.
• Patients should expect mild discomfort during passage of fragments and may see blood in the urine.
• Pain medication and alpha-blockers like tamsulosin 0.4 mg daily may be prescribed to facilitate stone passage.

Post-Treatment Care

• Following treatment, increased fluid intake of 2-3 liters daily is recommended to help flush out stone fragments.
• A follow-up imaging study should be scheduled 2-4 weeks after ESWL to confirm stone clearance.

Alternative Treatment

• URS is recommended for patients with suspected cystine or uric acid ureteral stones, but for this patient, ESWL is a suitable option 1.
• Routine stenting should not be performed in patients undergoing SWL, unless there is a suspected ureteric injury or other anatomical impediments to stone fragment clearance 1.

From the Research

Stone Characteristics

• The right kidney has a tiny stone at the mid calyces measuring about 2 mm with 112 HU, and another stone is seen in the proximal right ureter at the level of L3 vertebral body with mild upstream hydroureteronephrosis measuring about 7 mm with 1375 HU 2, 3.
• The size and density of the stones are important factors in determining the success of extracorporeal shock wave lithotripsy (ESWL) 3, 4.

ESWL Indications and Contraindications

• ESWL is a minimally invasive technique for the fragmentation of urinary tract stones using shock waves under fluoroscopic and/or ultrasound guidance 2, 3.
• The upper size limit of kidney stones for ESWL has been lowered to 15mm due to the increased risk of steinstrasse with larger sizes and the potential need of anesthesia and ureteral stenting 3.
• The selection of patients eligible for ESWL is dependent on the location and size of the stones and the overall health of the patient 5, 4.

Treatment Outcomes

• The success of ESWL depends on various technical factors as well as patient selection, including skin to stone distance, stone density and composition, size and location of the stone within the urinary system 2, 4.
• A slower rate with a gradual increasing voltage, precise targeting, and proper coupling can improve stone fragmentation and decrease the risk of complications 4.
• Ureteroscopy (URS) and ESWL are both effective and safe options for the treatment of upper ureteral stones, but URS is associated with a higher stone-free rate and fewer retreatments, while ESWL has a lower complication rate and shorter hospital stay 6.