Blackmon Richard L, Irby Pierce B, Fried Nathaniel M
Department of Physics and Optical Science, University of North Carolina at Charlotte, Charlotte, North Carolina 28223-0001, USA.
Lasers Surg Med. 2010 Jan;42(1):45-50. doi: 10.1002/lsm.20883.
The Thulium fiber laser has recently been tested as a potential alternative to the Holmium:YAG laser for lithotripsy. This study explores use of a short taper for expanding the Thulium fiber laser beam at the distal tip of a small-core fiber.
Thulium fiber laser radiation with a wavelength of 1,908 nm, 10 Hz pulse rate, 70 mJ pulse energy, and 1-millisecond pulse duration was delivered through a 2-m-length fiber with 150-microm-core-input-end, 300-microm-core-output-end, and 5-mm-length taper, in contact with human uric acid (UA) and calcium oxalate monohydrate (COM) stones, ex vivo (n = 10 each). Stone mass loss, stone crater depths, fiber transmission losses, fiber burn-back, irrigation rates, and deflection through a flexible ureteroscope were measured for the tapered fiber and compared with conventional fibers.
After delivery of 1,800 pulses through the tapered fiber, mass loss measured 12.7+/-2.6 mg for UA and 7.2+/-0.8 mg COM stones, comparable to conventional 100-microm-core fibers (12.6+/-2.5 mg for UA and 6.8+/-1.7 mg for COM stones). No transmission losses or burn-back occurred for the tapered fiber after 36,000 pulses, while a conventional 150-microm fiber experienced significant tip degradation after only 1,800 pulses. High irrigation rates were measured with the tapered fiber inserted through the working port of a flexible ureteroscope without hindering its deflection, mimicking that of a conventional 150 microm fiber.
The short tapered distal fiber tip allows expansion of the laser beam, resulting in decreased fiber tip damage compared to conventional small-core fibers, without compromising fiber bending, stone vaporization efficiency, or irrigation rates.
最近对铥光纤激光器进行了测试，作为钬：钇铝石榴石激光碎石术的一种潜在替代方案。本研究探讨了使用短锥度来扩展小芯光纤远端的铥光纤激光束。
波长为1908nm、脉冲频率为10Hz、脉冲能量为70mJ、脉冲持续时间为1毫秒的铥光纤激光辐射通过一根长度为2米的光纤传输，该光纤输入端芯径为150微米，输出端芯径为300微米，锥度长度为5毫米，与人体尿酸（UA）和一水草酸钙（COM）结石进行体外接触（每种结石n = 10）。测量了锥形光纤的结石质量损失、结石坑深度、光纤传输损耗、光纤烧蚀、冲洗速率以及通过柔性输尿管镜的偏转，并与传统光纤进行比较。
通过锥形光纤传输1800个脉冲后，UA结石的质量损失为12.7±2.6mg，COM结石为7.2±0.8mg，与传统的100微米芯径光纤相当（UA结石为12.6±2.5mg，COM结石为6.8±1.7mg）。锥形光纤在36000个脉冲后未出现传输损耗或烧蚀，而传统的150微米光纤仅在1800个脉冲后就出现了明显的尖端退化。将锥形光纤插入柔性输尿管镜的工作通道时测量到高冲洗速率，且不妨碍其偏转，这与传统的150微米光纤类似。
短锥形远端光纤尖端可使激光束扩展，与传统小芯光纤相比，可减少光纤尖端损伤，同时不影响光纤弯曲、结石汽化效率或冲洗速率。
