Mainil-Varlet P, Monin D, Weiler C, Grogan S, Schaffner T, Züger B, Frenz M
Institutes of Pathology and Applied Physics, University of Bern, Switzerland.
J Bone Joint Surg Am. 2001 Apr;83(4):566-71. doi: 10.2106/00004623-200104000-00012.
The application of lasers in orthopaedic surgery is increasing. However, some investigators have reported that osteonecrosis may occur after laser meniscectomy. The objective of the present study was to evaluate the effect of laser wavelength and energy on cartilage injury in an ex vivo model.
Fresh bovine articular cartilage was exposed to either holmium:yttrium-aluminum-garnet (Ho:YAG) or erbium:YAG-laser (Er:YAG) irradiation. Both lasers were operated in a free-running mode and at a pulse-repetition rate of 8 Hz. The effect of laser treatment at several energy levels (Er:YAG at 100 and 150 mJ and Ho:YAG at 500 and 800 mJ) was examined. For each light source and energy level, ten cartilage samples were assessed by conventional histological analysis and by confocal microscopy. Thermal damage was assessed by determining cell viability.
The extent of thermal damage demonstrated by confocal microscopy was much greater than that demonstrated by histological analysis. The extent of thermal injury after Ho:YAG-laser irradiation was much greater than that after Er:YAG-laser irradiation, which was associated with almost no damage. In addition, the ablation depth was greater after treatment with the Er:YAG laser than after treatment with the Ho:YAG laser.
In the present study, histological analysis underestimated thermal damage after laser irradiation. In addition, our findings highlighted problems associated with use of high-power settings of Ho:YAG lasers during arthroscopic surgery.
激光在骨科手术中的应用日益增加。然而，一些研究者报告称，激光半月板切除术后可能会发生骨坏死。本研究的目的是在体外模型中评估激光波长和能量对软骨损伤的影响。
将新鲜牛关节软骨暴露于钬：钇铝石榴石（Ho:YAG）或铒：钇铝石榴石激光（Er:YAG）照射下。两种激光均以自由运行模式操作，脉冲重复频率为8Hz。研究了几种能量水平（Er:YAG为100和150mJ，Ho:YAG为500和800mJ）的激光治疗效果。对于每种光源和能量水平，通过传统组织学分析和共聚焦显微镜对10个软骨样本进行评估。通过测定细胞活力评估热损伤。
共聚焦显微镜显示的热损伤程度远大于组织学分析显示的程度。Ho:YAG激光照射后的热损伤程度远大于Er:YAG激光照射后的热损伤程度，后者几乎没有损伤。此外，Er:YAG激光治疗后的消融深度大于Ho:YAG激光治疗后的消融深度。
在本研究中，组织学分析低估了激光照射后的热损伤。此外，我们的研究结果突出了关节镜手术中使用高功率设置的Ho:YAG激光相关的问题。
