Bhatta K M, Rosen D I, Dretler S P
Department of Urology, Massachusetts General Hospital, Boston 02114.
J Urol. 1989 Oct;142(4):1110-2. doi: 10.1016/s0022-5347(17)39007-9.
A technique for safer and more effective pulsed laser lithotripsy of urinary and biliary calculi was investigated in vitro. The technique involves enclosing the distal end of the laser delivery fiber in a "plasma shield." The plasma shield is a specially designed metal cap that serves to transfer the laser-induced mechanical impulse to the calculus while shielding surrounding tissue from direct laser exposure and thermal radiation. The metal cap also offers the advantage of effectively blunting the sharp fiber tip and improving its visualization under fluoroscopy. Plasma shield lithotripsy using a 200 micron quartz fiber inserted into a section of a modified 0.034 in. diameter stainless steel guide wire was tested in vitro on a variety of calculi and compared with results obtained using a 200 micron laser fiber applied directly. Calculi tested included cystine, struvite and calcium oxalate dihydrate urinary stones and pigmented cholesterol gallstones. The laser source was a flashlamp-pumped dye laser producing pulses of 1.2 microsecond duration and operated at a wavelength of 504 nm and pulse repetition frequency of 5 Hz. The results show that plasma shield lasertripsy is as effective as direct lasertripsy for fragmenting gallstones, struvite and calcium oxalate dihydrate calculi, is potentially safer, and can fragment cystine calculi which the pulsed dye laser applied directly cannot.
体外研究了一种用于泌尿系统和胆道结石更安全、更有效的脉冲激光碎石术的技术。该技术包括将激光传输光纤的远端封闭在一个“等离子体屏蔽罩”中。等离子体屏蔽罩是一种特殊设计的金属帽，它可以将激光诱导的机械脉冲传递到结石上，同时保护周围组织免受激光直接照射和热辐射。金属帽还具有有效钝化尖锐光纤尖端并在荧光镜下改善其可视性的优点。使用插入到一段改良的0.034英寸直径不锈钢导丝中的200微米石英光纤进行等离子体屏蔽碎石术，在体外对各种结石进行了测试，并与直接使用200微米激光光纤获得的结果进行了比较。测试的结石包括胱氨酸、鸟粪石和二水合草酸钙尿路结石以及色素性胆固醇胆结石。激光源是一个闪光灯泵浦染料激光，产生持续时间为1.2微秒的脉冲，工作波长为504纳米，脉冲重复频率为5赫兹。结果表明，等离子体屏蔽碎石术在破碎胆结石、鸟粪石和二水合草酸钙结石方面与直接碎石术一样有效，可能更安全，并且可以破碎直接应用脉冲染料激光无法破碎的胱氨酸结石。
