From the Guidelines
The patient with a 7 mm stone in the proximal right ureter at the L3 vertebral level with mild hydroureteronephrosis should be offered Ureteroscopy (URS) as the first-line therapy, rather than Extracorporeal Shock Wave Lithotripsy (ESWL), due to its higher stone-free rate in a single procedure, as recommended by the American Urological Association/Endourological Society guideline 1. The patient has two kidney stones: a small 2 mm stone in the right kidney's mid calyces with a density of 112 Hounsfield Units (HU), and a larger 7 mm stone in the proximal right ureter at the L3 vertebral level with a density of 1375 HU.
- The larger stone is causing mild hydroureteronephrosis (swelling of the ureter and kidney) and requires intervention because of its size and the blockage it's causing.
- The smaller 2 mm kidney stone may pass spontaneously and can be monitored. According to the guideline 1, URS is associated with significantly higher stone-free rates in a single procedure compared to SWL, particularly for patients with <10 mm mid and distal ureteral calculi.
- During recovery, the patient should increase fluid intake to 2-3 liters daily, take prescribed pain medications as needed (typically NSAIDs like ibuprofen 400-600 mg every 6-8 hours or narcotic analgesics for severe pain), and possibly alpha-blockers like tamsulosin 0.4 mg daily to help with stone passage.
- The patient should strain their urine to collect stone fragments for analysis, which will help determine stone composition and guide preventive measures.
- Follow-up imaging will be necessary to confirm complete stone clearance after treatment. It's also important to note that routine stenting should not be performed in patients undergoing URS, unless there are specific indications such as suspected ureteric injury or ureteral stricture 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) 4.
Indications for ESWL
- ESWL is indicated for the treatment of renal and ureteral stones, and the selection of favorable cases can optimize the results 2.
- The upper size limit of kidney stones for ESWL has been lowered to 15mm due to the increased risk of steinstrasse with larger sizes 3.
- The location of the stone, skin to stone distance, and anatomy of the excretory path are also important factors in determining the success of ESWL 4.
Technical Factors
- Technical factors such as the type of lithotripsy device, energy and frequency of pulses, coupling of the patient to the lithotriptor, and type of anesthesia can impact the success of ESWL 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.
Comparison with Other Treatments
- ESWL and ureteroscopy (URS) are the most common treatments for upper ureteric stones, and the choice of treatment depends on individual patient circumstances and preferences 5.
- URS is associated with a higher stone-free rate, fewer retreatments, and fewer secondary procedures, but also with a higher need for adjunctive procedures, greater complication rates, and longer hospital stay compared to ESWL 5.