In Vitro Biliary Lithotripsy By Q-switched Versus Continuous Wave Nd/YAG Laser

ABSTRACT

In this work, the role of the Q-switched and continuous wave [CW] NdYAG laser biliary lithotripsy was studied. A total of 120 biliary stones was randomly divided into two groups [A and B], which were conducted to CW and Q-switched NdYAG laser, respectively. A radiological and spectroscopic examination was done. Gall bladder wall exposure to both laser techniques was done, then was subjected to gross and microscopic examination. During Q-switched technique at the same volume of cholesterol stones, the fragmenting pulse number was inversely proportionate to the spectroscopic calcium [Ca%] content of the stones. Moreover, the thermal effect of both techniques on the gall bladder wall was evaluated. It can be concluded that CW has a hazardous thermal effect on the soft tissue surroundings which limits its use in biliary lithotripsy. The Q-switched NdYAG laser is an effective and safe method for biliary lithotripsy. The fragmenting pulse number depends on the pigment content of the stones. In cholesterol stones, the fragmentation pulse number is inversely proportionate to the Ca content of the stone