This information paper has been prepared by the NHTAP to provide an overview of developments in equipment for extracorporeal shock wave lithotripsy (ESWL). ESWL is a technique for non-invasive disintegration of stones in the kidney and ureteral tract.   More recently it has been used to disintegrate biliary stones.  A full NHTAP report on lithotripsy of biliary stones is expected to be completed during 1988.

In June 1985 the NHTAP issued a report on ESWL (1), noting that there might be rapid developments in the technology and that these should be monitored.  Second generation devices have now been produced by a number of manufacturers and some are being used clinically overseas.  These machines vary in the technique used for shock wave generation and imaging of stones.  Acoustic coupling has been simplified through the use of an enclosed column of water in a plenum rather than a water bath.  In some cases, the lithotripter is a dedicated single purpose machine.  In others, the table design allows other procedures to be undertaken.  The relative attractions of the two approaches for purchasers will depend on available workload and other resources.