Majdani Omid, Wittkopf Justin, Dietrich Mary S, Labadie Robert F
Department of Otolaryngology, Medical University of Hannover, Hannover 30659, Germany.
Lasers Surg Med. 2009 Sep;41(7):509-13. doi: 10.1002/lsm.20800.
Recently, a new, flexible-fiber, CO2 laser delivery system has been FDA-cleared for clinical use. However, for otologic surgery, no data have been reported correlating power settings to depth of penetration into the otic capsule-the bone that covers the inner ear. This was the goal of our study.
STUDY DESIGN/MATERIALS AND METHODS: Eight cadaveric temporal bones were procured as per our institution's protocols. For each specimen, nine different laser holes were burned into the otic capsule using the flexible-fiber CO2 laser delivery system. Power settings were varied from 10 to 20 W in 2 W increments, and duration of exposure was 100, 200, 300, 400, or 600 milliseconds. Each setting (power and duration) was tested on two specimens. Following laser exposure, each specimen was scanned in a microCT scanner, and the depth of penetration measured from these images.
Of the 72 laser shots, 8 were excluded due to double hits (4), oblique hits (3), or complete penetration (1). After excluding these 8, bone penetration was found to vary from 160 to 670 microm based on power and time settings. Spearman analysis on ranked data showed that time had a greater impact on depth than power. The correlation coefficients for time and power were 0.84 (P = 0.013) and 0.40 (P<0.001), respectively.
The flexible-fiber CO2 laser is effective for otic capsule ablation in this model. High power setting and long pulse duration can lead to complete penetration of the otic capsule potentially causing damage of underlying structures such as the facial nerve, horizontal semicircular canal, and cochlea.
最近，一种新型的柔性光纤二氧化碳激光传输系统已获得美国食品药品监督管理局（FDA）批准可用于临床。然而，对于耳科手术，尚无数据报道功率设置与内耳骨质覆盖层（即耳囊）的穿透深度之间的关系。这就是我们这项研究的目的。
研究设计/材料与方法：按照我们机构的方案获取了8个尸体颞骨。对于每个标本，使用柔性光纤二氧化碳激光传输系统在耳囊上烧灼9个不同的激光孔。功率设置以2瓦的增量从10瓦变化到20瓦，暴露持续时间为100、200、300、400或600毫秒。每个设置（功率和持续时间）在两个标本上进行测试。激光照射后，每个标本在微型计算机断层扫描（microCT）扫描仪中进行扫描，并从这些图像中测量穿透深度。
在72次激光照射中，有8次因双重击中（4次）、斜向击中（3次）或完全穿透（1次）而被排除。排除这8次后，发现基于功率和时间设置，骨穿透深度在160至670微米之间变化。对排序后的数据进行斯皮尔曼分析表明，时间对深度的影响大于功率。时间和功率的相关系数分别为0.84（P = 0.013）和0.40（P<0.001）。
在该模型中，柔性光纤二氧化碳激光对耳囊消融有效。高功率设置和长脉冲持续时间可能导致耳囊完全穿透，从而可能损害面神经、水平半规管和耳蜗等深部结构。
