Objective: To evaluate the influence of the site and dimensions of ureteric stones on the modalities and performances of in situ piezoelectric extracorporeal shockwave lithotripsy (ESWL).
Material and methods: A population of 385 patients with solitary radiopaque ureteric stones was analysed. The long axis of these stones (211 (55%) lumbar, 38 (10%) iliac and 136 (35%) pelvic stones) ranged from 5 to 21 mm (mean = 8.2 mm). The initial shock wave frequency was 4/s. Lumbar stones were treated in the dorsal supine position under diaz-analgesia and pelvic stones were treated in the ventral supine position without systematic sedation. The influence of wave frequency (1 versus 4/s) on the level of sedation and therapeutic performances was studied on 146 patients with lumbar (n = 92) or pelvic stones (n = 54). The results were evaluated after only one ESWL session and were analysed statistically by Student's test and Fisher test.
Results: The overall complete success rate was 74%. Iliac stones were characterized by significantly (p < 0.05) lower (61%) performances. The results were inversely proportional to the size of the stones, as the complete success rate was only 25% for stones > 12 mm. For lumbar stones, a lower frequency allowed a very significant reduction (p < 0.0001) of the level of sedation required without affecting the performance. For pelvic stones, a low frequency significantly (p < 0.05) limited the efficacy of ESWL, especially for stones > 8 mm (27% of complete successes).
Conclusion: In situ piezoelectric ESWL allows effective management of most ureteric stones with of long axis between 5 and 10 mm. In the context of outpatient treatment, however, this approach requires modulation of the shock wave frequency according to the site of the stone. Another therapeutic approach, particularly endoscopy, should be considered for very large stones.