Methyl tert-butyl ether improves the efficacy of extracorporeal shock wave lithotripsy of human gallstones implanted in pigs.

OBJECTIVE

To investigate the contribution of contact dissolution with methyl tert-butyl ether (MTBE) to the success of extracorporeal shock wave lithotripsy (ESWL) of human gallstones implanted in pigs.

DESIGN

Experimental study of matched pairs.

SETTING

Laboratory for experimental surgery, The Netherlands.

MATERIAL: 30 pigs.

INTERVENTIONS: Couples of similar human gallstones were surgically implanted into the gallbladders of 30 pigs. All pigs underwent ESWL with an electromagnetic lithotriptor. Half the animals were given adjuvant treatment with MTBE for 2 hours immediately after the ESWL. All pigs were killed a week after treatment.

RESULTS

Adjuvant MTBE dissolution led to superimposed damage of the gallbladder. One pig died of biliary leakage and peritonitis. For all kinds of stones, adjuvant MTBE treatment increased the median (range) percentage of stone dissolved by ESWL from 31 (0-58) to 60 (11-81) (p < 0.01), whereas for pure cholesterol stones the increase was from 23 (0-58) to 61 (11-81) (p < 0.01).

CONCLUSIONS

These data warrant clinical evaluation of the applicability of combined ESWL and MTBE dissolution of symptomatic gallstones in selected patients.