Adanur S et al, 2014: What should be the ideal time interval between repeated extracorporeal shock wave lithotripsy sessions for renal stone treatment?
Adanur S, Ziypak T, Yapanoglu T, Polat O
Medical Faculty, Department of Urology, Ataturk University, Erzurum, Turkey,
Letter without abstract.
Urolithiasis. 2014 Oct;42(5):471. doi: 10.1007/s00240-014-0685-9. Epub 2014 Jul 17.
One determinant of the risk of bleeding complications during repeat SWL might be related to the presence or absence of renal contusions that remain after a previous session. It therefore certainly is wise to allow sufficient time to pass between two consecutive SWL sessions directed towards the kidney. Although it has been stated that 7 days are enough, I have a feeling that very few contusions have healed after that period. My own routine therefore has been to wait 2 weeks if possible, at least if the same area of the kidney will be in focus.
Support for this routine is obtained from one experimental study on normal and diabetic rats . The apoptotic index was increased in the latter group when the animals were re-treated within 2 weeks. The explanation for that are probably vascular abnormalities and inasmuch as such abnormalities cannot be excluded in human adult kidneys, it might be a careful precaution to avoid re-treatment too early. Moreover, it was observed in a recent study  that KIM-1 and NAG analysed after SWL returned to baseline within approximately 2 weeks after SWL. Exact kinetics is not available, but intuitively it seems wise to wait at least 7 days. A longer interval might be recommended for patients with reduced renal function, a history of hypertension, diabetes or high age.
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