Inadvertent fracture of gallstones during extracorporeal shock wave lithotripsy

The effect of extracorporeal shock wave lithotripsy on the prosthesis interface in cementless arthroplasty. Evaluation in a rabbit model

The effect of extracorporeal shock wave lithotripsy on interfacial strength between prosthesis and bone in cementless arthroplasty was examined using a rabbit model. Paired femora, each implanted with fiber mesh porous coated titanium implants, were harvested from rabbits 15 weeks after implantation. In group I, one femur from each pair was exposed to lithotripsy treatment consisting of 2,000 shocks at 20 kV. In group II, one femur from each pair was exposed to 2,000 shocks at 26 kV. Contralateral femora from each pair served as controls in both groups. Mechanical pushout tests were conducted on the implants using a 1321 Instron testing machine at a constant rate of 1 mm/minute. Shock waves generated at 20 kV were found to have no significant decrease on either the prosthesis/bone interfacial strength or energy to failure of cementless implants. Shock waves generated at 26 kV produced a mean 17.45% decrease in the prosthesis/bone interfacial strength, which approached statistical significance (P = .062), and a 7.84% mean decrease in the energy to failure (P = .268). However, in four of the seven group II specimens, cortical fractures occurred. These findings suggest that lithotripsy will not aid in the removal of uncemented porous coated devices and lithotripsy inadvertently focused at an uncemented device will not disrupt significantly the prosthesis-bone interface.

Mechanical property studies of human gallstones

The recent development of gallstone fragmentation methods has increased the significance of the study of the mechanical properties of human gallstones. In the present work, fracture strength data and microhardness values of gallstones of various chemical compositions are presented as tested in both dry and simulated bile environments. Generally, both gallstone hardness and fracture strength values were significantly less than kidney stone values found in previous studies. However, a single calcium carbonate stone was found to have an outer shell hardness exceeding those values found for kidney stones. Diametral compression measurements in simulated bile conclusively demonstrated low gallstone fracture strength as well as brittle fracture in the stones tested. Based on the results of this study, one may conclude that the wide range of gallstone microhardnesses found may explain the reported difficulties previous investigators have experienced using various fragmentation techniques on specific gallstones. Moreover, gallstone mechanical properties may be relatively sensitive to bile-environment composition.

Removal of common bile duct stones by the combination of percutaneous balloon dilatation and extracorporeal shock-wave lithotripsy

Endoscopic papillotomy may not be possible in patients who have previously undergone gastric surgery. We describe the successful treatment of such a patient with ultrasound-guided, percutaneous transhepatic biliary drainage, followed by balloon dilatation of the sphincter of Oddi and extracorporeal shock-wave lithotripsy. Combinations of new treatment forms may be necessary and effective when single forms of treatment fail.

Urinary extracorporeal shock wave lithotripsy: equipment, techniques, and overview

Second generation urinary lithotriptors are characterized by extensive technical alterations and significant equipment improvement in the functional, logistical, and medical aspects of shock wave lithotripsy (SWL). These newer devices feature a water bath-free environment, a reduced anesthesia requirement, improved imaging, functional uses in addition to lithotripsy, or combinations thereof. Shock wave generation by spark gap, electromagnetic, piezoelectric and microexplosive techniques are related to their peak energy, frequency, and total energy capabilities which impacts on both anesthesia needs and the length and number of treatment sessions required to pulverize calculi. A master table summarizes the types of SW energy, coupling, imaging systems, patient transport, functional features, cost, and treatment effectiveness of 12 worldwide lithotriptors in various stages of investigative and clinical trials as monitored by the Food and Drug Administration (FDA) of America.

Biliary obstruction complicating extracorporeal shock wave lithotripsy

An elderly woman with a solitary right kidney and unrecognized cholelithiasis underwent extracorporeal shock wave lithotripsy for renal calculi. Postoperatively, biliary obstruction developed that required emergency surgery. Pathological evaluation of the biliary calculi revealed superficial fragmentation. It is suggested that extracorporeal shock wave lithotripsy was responsible for the gallstone fragmentation and resultant bile duct obstruction.