Is a 2 mm renal stone in the right kidney and a 7 mm ureteral stone in the proximal right ureter with mild hydroureteronephrosis (Hydronephrosis) indicated for Extracorporeal Shock Wave Lithotripsy (ESWL)?

From the Guidelines

The patient with a 7 mm stone in the proximal right ureter at the L3 vertebral level with mild hydroureteronephrosis is a candidate for Ureteroscopy (URS) as the first-line treatment, rather than Extracorporeal Shock Wave Lithotripsy (ESWL), according to the most recent guidelines 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 ureteral stone is causing mild hydroureteronephrosis (swelling of the ureter and kidney) and requires intervention. According to the guidelines, for proximal ureteral stones, URS is recommended as the first surgical modality regardless of stone size 1. The high density (1375 HU) of the ureteral stone indicates it's likely composed of calcium oxalate or calcium phosphate, which are typically responsive to treatment. During recovery, the patient should increase fluid intake to 2-3 liters daily, take prescribed pain medications as needed, and possibly alpha-blockers like tamsulosin to help with stone passage. Follow-up imaging will be necessary to confirm complete stone clearance. Some key points to consider in the management of this patient include:

• The size and location of the stone, as well as the presence of hydroureteronephrosis, dictate the need for intervention 1.
• The choice of treatment, either URS or ESWL, depends on the size and location of the stone, as well as the patient's overall health and preferences 1.
• The patient should be closely monitored for any changes in symptoms or stone size, and follow-up imaging should be performed to confirm complete stone clearance 1.

From the Research

Stone Size and Location

• 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.
• The size and location of the stones are important factors in determining the appropriate treatment, with ESWL being a suitable option for smaller stones 3, 4.

Treatment Options

• ESWL is a minimally invasive technique for fragmenting urinary tract stones using shock waves under fluoroscopic and/or ultrasound guidance 2.
• The study by 3 found that stone elimination is determined by size and localization, with stones in the ureter having an 80% chance of spontaneous elimination.
• Ureteroscopy is also an effective treatment option for kidney stones, especially for stones ≤2 cm 5.
• The choice between ESWL and ureteroscopy depends on various factors, including stone size, location, and patient preferences 4, 5.

ESWL Indications

• The upper size limit for kidney stones treated with ESWL has been lowered to 15mm due to the increased risk of steinstrasse with larger sizes 2.
• ESWL is indicated for stones in the proximal ureter, with a success rate of 90% for monotherapy 4.
• The study by 5 found that ESWL is a viable alternative to ureteroscopy for stones ≤2 cm, especially for 6-10-mm stones.

Stone Density and Fragmentation

• The density of the stone, measured in Hounsfield units (HU), influences the fragmentation achieved by ESWL 2.
• The study by 6 found that the stone-free rate decreases as the stone size increases, and the number of operations required also increases.
• The choice of treatment should take into account the stone density and size to ensure effective fragmentation and minimal complications 2, 6.