The relationship between the energy levels of shock waves and the degree of renal damage after ESWL: a prospective clinical matching trail.

In an attempt to understand the effects of high energy shock wave (HESW) on renal function, we studied prospectively 40 patients with nephrolithiasis in 4 groups, using same voltage with different numbers of shock wave therapy to identify the difference of effects on renal function. Stone burdens and position were similar in these groups. Each group received 1500, 2000, 2500 or 3000 pulses at 12.5 KV on JT-3 lithotripotor respectively. All the groups had significantly increased the levels of urinary NAG, beta 2MG, ALB and serum beta 2MG, which reached the highest values on 1-3 days after ESWL (P < 0.001), and then decreased to the pre-ESWL levels except urinary NAG in group C and D and serum beta 2MG which were still significantly higher (P < 0.05) than those before-ESWL on the 7th day after ESWL. There was significant correlation between either urinary NAG (gamma = 0.977, P < 0.05) or beta 2MG (gamma = 0.933, P < 0.001) with the number of shock wave. In addition, urinary NAG and beta 2MG increased significantly when the number of shock waves was over 2500 shots. These above findings suggest that shock wave had induced acute changes in renal functions and transient renal tubular damages, although these functional changes recovered within one week, and the tubular damage might last longer than 7 days, In order to avoid serious renal damage, it's necessary to limit the energy level of shock waves under 12.5 KV x 2500 shots by using JT-3 lithotriptor.