Majaron B, Kelly K M, Park H B, Verkruysse W, Nelson J S
Beckman Laser Institute and Medical Clinic, University of California, Irvine, California 92612, USA. boris.majaron@ijs
Lasers Surg Med. 2001;28(2):121-30. doi: 10.1002/lsm.1026.
To evaluate histologically the characteristics of repetitive Er:YAG laser exposure of skin in combination with cryogen spray cooling (CSC), and its potential as a method of laser skin resurfacing.
STUDY DESIGN/MATERIALS AND METHODS: Rat skin was irradiated in vivo with sequences of 10 Er:YAG laser pulses (repetition rate 20 Hz, pulse duration 150 or 550 micros, single-pulse fluence 1.3-5.2 J/cm(2)). In some examples, CSC was applied to reduce epidermal injury. Histologic evaluation was performed 1 hour, 1 day, 5 days, and 4 weeks post-irradiation.
A sequence of ten 550-micros pulses with fluences around 2 J/cm(2) resulted in acute dermal collagen coagulation to a depth of approximately 250 microm, without complete epidermal ablation. CSC improved epidermal preservation, but also diminished the coagulation depth. Four weeks after irradiation, neo-collagen formation was observed to depths in excess of 100 microm.
Dermal collagen coagulation and neo-collagen formation to depths similar to those observed after CO(2) laser resurfacing can be achieved without complete ablation of the epidermis by rapidly stacking long Er:YAG laser pulses. Application of CSC does not offer significant epidermal protection for a given dermal coagulation depth.
通过组织学方法评估重复发射的铒：钇铝石榴石（Er:YAG）激光联合冷冻喷雾冷却（CSC）对皮肤的作用特点，及其作为一种激光皮肤磨削方法的潜力。
研究设计/材料与方法：对大鼠皮肤进行体内照射，采用10个Er:YAG激光脉冲序列（重复频率20Hz，脉冲持续时间150或550微秒，单脉冲能量密度1.3 - 5.2J/cm²）。部分实验中，应用CSC以减轻表皮损伤。在照射后1小时、1天、5天和4周进行组织学评估。
一系列10个550微秒脉冲，能量密度约为2J/cm²，可导致真皮胶原急性凝固至约250微米深度，而表皮未完全剥脱。CSC改善了表皮保存情况，但也减小了凝固深度。照射4周后，观察到新生胶原形成深度超过100微米。
通过快速叠加长Er:YAG激光脉冲，可在不完全剥脱表皮的情况下，实现与二氧化碳激光磨削后类似深度的真皮胶原凝固和新生胶原形成。对于给定的真皮凝固深度，CSC并未提供显著的表皮保护作用。
