Treatment protocols to reduce renal injury during shock wave lithotripsy.

PURPOSE OF REVIEW

Growing concern over the acute and long-term adverse effects associated with shock wave lithotripsy calls for treatment strategies to reduce renal injury and improve the efficiency of stone breakage in shock wave lithotripsy.

RECENT FINDINGS

Experimental studies in the pig model show that lithotripter settings for power and shock wave rate and the sequence of shock wave delivery can be used to reduce trauma to the kidney. Step-wise power ramping as is often used to acclimate the patient to shock waves causes less tissue trauma when the initial dose is followed by a brief (3-4 min) pause in shock wave delivery. Slowing the firing rate of the lithotripter to 60 shock waves/min or slower is also effective in reducing renal injury and has the added benefit of improving stone breakage outcomes. Neither strategy to reduce renal injury -- not power ramping with 'pause-protection' nor delivering shock waves at reduced shock wave rate --- have been tested in clinical trials.

SUMMARY

Technique in lithotripsy is critically important, and it is encouraging that simple, practical steps can be taken to improve the safety and efficacy of shock wave lithotripsy.