Impact of hydronephrosis on shockwave lithotripsy outcomes for upper ureteral stones

To investigate the effect of the degree of hydronephrosis on extracorporeal shockwave lithotripsy (SWL) success in patients who underwent SWL due to upper ureteral stones.

Medical records of 878 patients who underwent SWL were retrospectively reviewed. Patients with isolated unilateral 6-10 mm radiopaque upper ureteral stones above the upper border of the sacroiliac joint were included in the study. The primary endpoint of the study was the relationship between the degree of hydronephrosis with upper ureteral stones and the stone clearance time, number of SWL sessions, and success, while the secondary endpoint was the effect of the presence of severe hydronephrosis (SFU grade 3) on SWL success.

The mean age of the patients was 41.3 ± 10.9 years. The mean stone size was 8.2 (6-10) mm. Ureteropelvic junction stones were present in 24 (20%) patients. The mean stone clearance time was 14.6 ± 9.7 days. One-month SWL success was determined as 85%. SWL success rates decreased as the degree of hydronephrosis increased (p = 0.047). Being 45 years of age and older increased the risk of SWL failure by 16.25 times (OR = 16.25, p = 0.017). Increasing the stone clearance time by 1 day increased the risk of SWL failure by 1.17 times (OR = 1.17, p = 0.006), and increasing the number of SWL sessions by 1 session increased the risk of SWL failure by 7.69 times (OR = 7.69, p = 0.016). The presence of severe hydronephrosis (grade 3) did not affect SWL success (OR = 5.56, p = 0.071).

According to our study results, as the degree of hydronephrosis increases in 6-10 mm upper ureteral stones, the number of SWL sessions increases, stone expulsion times prolong, and 1-month success rates decrease.