Can intervals in extracorporeal shock wave lithotripsy sessions affect success in the treatment of upper ureteral stones?

Introduction
Managing upper ureteral stones with shock wave lithotripsy (SWL) has been done for many years. However, no conclusive data have been found on the intervals required between repeated SWL sessions.

Aim
To identify the most optimal intervals between SWL sessions.

Material and methods
Between September 2015 and December 2016, 80 patients undergoing elective outpatient lithotripsy who required repeated SWL sessions for ureteral stones were evaluated. These patients were categorised into two groups according to different SWL session intervals. The intervals between SWL sessions (n = 40) for the first group lasted one day, whereas those for the second group (n = 40) lasted 1 week. The data recorded during SWL included visual analogue scale (VAS) scores, total number of shocks, total energy used and number of sessions. The stone clearance rates, number of urinary tract infections, complication rates and VAS scores were compared between the two groups.

Results
All patients’ clinical outcomes after SWL therapy are shown in Table I. The stone clearance rate for group 1 was 70%, whereas that for group 2 was 72.5% (p = 0.805). Additionally, the number of urinary tract infections, complications and VAS scores were similar for both groups. In group 1, 3 patients had steinstrasse, two suffered from severe renal colic, and one had a urinary tract infection. In group 2, 3 patients endured steinstrasse, and 2 patients experienced severe renal colic during the study.

Conclusions
Short-interval SWL sessions are safe and effective for treating upper ureteral stones, and such sessions do not increase complication rates.