| Abstract: | Nd-YAG laser exposure via percutaneous-transhepatic cholangioscopy (PTCS) has been used successfully in destruction of bilirubin stones in threepatients with huge commen bile duct (CBD) stonesor intrahepatic stones, which couldn't be removed byendoscopic sphincteropapillotomy (EST). Experi-mental studies were conducted to observe the changesin temperature of stone surface and the surroundingsin air or water, during laser cxposur:. In addition,the correlation between the elevation and recoveryof temperature of the surrounding water and the speed of water infusion was observed. A plastic tube of 6 mm in diameter was used as a model. The peaktemperature of stone surface 5 mm close to the con. tact point of the quartz fiber at point A, B and C was 5I C, 30 C, and 158 C respectively. No changes intemperature were observed at the three points whena similar experiment on the bilirubin stone was done but in a beaker with 400 ml water. The relationshipbetween the peak of temperature and the speed of water infusion was not significant, but the time needed for lowering a peak temperature to the original, after laser beam was delivered, was obviously related to the speed of water infusion. It should be emphasized that during the treatment of the biliary stone by Nd-YAG laser via PTCS, the water infusion at any time should be continued and it is better tokeep the speed of water infusion not less than40 ml/min. Of course, the free tip of the quartzfiber should be well contacted with the surface ofthe stone, so as to avoid a direct burn injury to thewall of the bile duct by laser beam. |
