Kuan Edward C, Hamamoto Ashley A, Sun Victor, Nguyen Tony, Manuel Cyrus T, Protsenko Dmitry E, Wong Brian J F, Nelson J Stuart, Jia Wangcun
Beckman Laser Institute and Medical Clinic, University of California - Irvine, 1002 Health Sciences Rd, Irvine, California, 92612.
Lasers Surg Med. 2014 Dec;46(10):791-5. doi: 10.1002/lsm.22305. Epub 2014 Nov 18.
BACKGROUND/OBJECTIVES: Similar to conventional cryogen spray cooling, carbon dioxide (CO2) spray may be used in combination with laser cartilage reshaping (LCR) to produce cartilage shape change while minimizing cutaneous thermal injury. Recent ex vivo evaluation of LCR with CO2 cooling in a rabbit model has identified a promising initial parameter space for in vivo safety and efficacy evaluation. This pilot study aimed to evaluate shape change and cutaneous injury following LCR with CO2 cooling in 5 live rabbits.
STUDY DESIGN/MATERIALS AND METHODS: The midportion of live rabbit ears were irradiated with a 1.45 µm wavelength diode laser (12 J/cm(2)) with simultaneous CO2 spray cooling (85 millisecond duration, 4 alternating heating/cooling cycles per site, 5 to 6 irradiation sites per row for 3 rows per ear). Experimental and control ears (no LCR) were splinted in the flexed position for 30 days following exposure. A total of 5 ears each were allocated to the experimental and control groups.
Shape change was observed in all irradiated ears (mean 70 ± 3°), which was statistically different from control (mean 37 ± 11°, P = 0.009). No significant thermal cutaneous injury was observed, with preservation of the full thickness of skin, microvasculature, and adnexal structures. Confocal microscopy and histology demonstrated an intact and viable chondrocyte population surrounding irradiated sites.
LCR with CO2 spray cooling can produce clinically significant shape change in the rabbit auricle while minimizing thermal cutaneous and cartilaginous injury and frostbite. This pilot study lends support for the potential use of CO2 spray as an adjunct to existing thermal-based cartilage reshaping modalities. An in vivo systematic evaluation of optimal laser dosimetry and cooling parameters is required.
背景/目的：与传统的冷冻剂喷雾冷却类似，二氧化碳（CO₂）喷雾可与激光软骨重塑（LCR）联合使用，以实现软骨形状改变，同时将皮肤热损伤降至最低。最近在兔模型中对LCR联合CO₂冷却进行的体外评估，已确定了一个有前景的初始参数空间，用于体内安全性和有效性评估。本初步研究旨在评估5只活兔在LCR联合CO₂冷却后的形状变化和皮肤损伤情况。
研究设计/材料与方法：用波长为1.45 µm的二极管激光（12 J/cm²）照射活兔耳朵中部，同时进行CO₂喷雾冷却（持续时间85毫秒，每个部位4个交替加热/冷却循环，每只耳朵每行5至6个照射部位，共3行）。实验耳朵和对照耳朵（未进行LCR）在暴露后于屈曲位置固定30天。实验组和对照组各分配5只耳朵。
在所有接受照射的耳朵中均观察到形状变化（平均70±3°），与对照组（平均37±11°，P = 0.009）相比有统计学差异。未观察到明显的皮肤热损伤，皮肤全层、微血管和附属结构均得以保留。共聚焦显微镜检查和组织学检查显示，照射部位周围软骨细胞群体完整且存活。
LCR联合CO₂喷雾冷却可在兔耳廓产生具有临床意义的形状变化，同时将皮肤热损伤、软骨损伤和冻伤降至最低。本初步研究支持将CO₂喷雾作为现有基于热的软骨重塑方式的辅助手段的潜在用途。需要对最佳激光剂量和冷却参数进行体内系统评估。
