The Ideal Time Interval Between Repeated Shock Wave Lithotripsy Sessions For Renal Stones: A Randomized Controlled Trial

There is no consensus about the required time intervals between repeated SWL sessions applied for renal stones with some centers waiting for 3 days, others for one week and others up to one month to repeat lithotripsy. In the 2019 EUA guidelines stated that "There are no conclusive data on the intervals required between repeated SWL sessions. However, clinical experience indicates that repeat sessions are feasible (within 1 day for ureteral stones).

The intense use of ESWL currently, the lack of knowledge about acute lesions caused by re-treatment within a short time interval and the empirical way by which treatment is conducted, stimulated us to search for a precise answers to the question What the ideal time interval between SWL sessions in the treatment of renal stone patients should be.

This randomized controlled trial will be conducted at Urology and Nephrology Center in Mansoura, Egypt. Patients more than 18 years old with single primary renal stone fulfilling inclusion criteria will be randomly allocated to 3 groups (50 patients each).Group 1 will undergo SWL with 3 days between each session. Group 2 will undergo SWL with 7 days between each session and Group 3 will undergo SWL with 14 days between each session.

Study parameters will be renal damage including the following items:

• Tubular damage will be assessed through estimation of changes in urinary excretion of renal tubular enzyme kidney injury molecule 1(KIM-1).
• Glomerular damage will be assessed by estimation of proteinuria and changes in GFR calculated by renal isotope scan.
• Renal morphological and haemodynamic changes.
• Treatment success is defined as clinically insignificant residual fragments less than 4 mm size.