Leclère Franck Marie P, Magalon Guy, Philandrianos Cécile, Unglaub Frank, Servell Pascal, Mordon Serge
(French National Institute of Health and Research), Université Lille Nord de France, Lille University Hospital CHRU, France.
J Cosmet Laser Ther. 2012 Feb;14(1):7-13. doi: 10.3109/14764172.2011.634419.
Laser Assisted Skin Healing (LASH) was first introduced in 2001 by Capon and Mordon to prevent keloids and hypertrophic scars. LASH requires homogenous heating throughout the full thickness of the skin around the wound. However, LASH therapy with 808-nm diode laser is deemed to be only applicable for phototype I-IV due to melanin absorption. This prospective ex-vivo study aims to evaluate the thermal effects of different wavelengths (808, 1064, 1210 and 1320 nm) on human skin phototype II, IV and VI.
Laser shots were applied on skin explants phototypes II, IV and VI. The following laser settings were used: 808, 1064, 1210 and 1320-nm diode laser, Spot size 20 × 3.7 mm, Power 3 W, Irradiance 4 W/cm², 50 shots for each phototype and wavelength. The surface temperature at 2 and 4-mm depth respectively was evaluated by an infrared camera and a low inertia micro thermocouple.
For the 1064, 1210 and 1320-nm wavelengths, the temperature gradient between the surface and 2-mm depth after an irradiation time of 15 s was less than 4.0°C for each phototype. For the 808 nm, the gradient was 0.8°C and 4.4°C in phototype II and IV respectively, but reached 17.2°C in phototype VI. Strong absorption by melanin of skin phototype VI induced unwanted temperature increases at the dermis-epidermis junction, making this wavelength unsuitable for LASH therapy for this phototype. Among the three other wavelengths, the discussion section indicates strong blood absorption at 1064 nm and presents both 1210 and 1320 nm as excellent compromises for LASH therapy across the whole range of phototypes.
Being poorly absorbed by melanin, both 1210 and 1320-nm wavelengths ensure homogeneity of temperature throughout the full skin explant thickness. Their possible utilization for efficient LASH therapy should now be confirmed by prospective in vivo studies.
激光辅助皮肤愈合（LASH）于2001年由卡彭和莫尔东首次提出，用于预防瘢痕疙瘩和增生性瘢痕。LASH要求在伤口周围皮肤的全层进行均匀加热。然而，由于黑色素吸收，808纳米二极管激光的LASH疗法被认为仅适用于I - IV型皮肤。这项前瞻性离体研究旨在评估不同波长（808、1064、1210和1320纳米）对II、IV和VI型人类皮肤的热效应。
对II、IV和VI型皮肤外植体进行激光照射。使用以下激光设置：808、1064、1210和1320纳米二极管激光，光斑尺寸20×3.7毫米，功率3瓦，辐照度4瓦/平方厘米，每种皮肤类型和波长照射50次。分别通过红外热像仪和低惯性微型热电偶评估2毫米和4毫米深度处的表面温度。
对于1064、1210和1320纳米波长，照射15秒后，每种皮肤类型在表面和2毫米深度之间的温度梯度小于4.0°C。对于808纳米，II型皮肤的梯度为0.8°C，IV型皮肤为4.4°C，但VI型皮肤达到17.2°C。VI型皮肤中黑色素的强烈吸收导致真皮 - 表皮交界处出现不必要的温度升高，使得该波长不适用于该皮肤类型的LASH疗法。在其他三种波长中，讨论部分指出1064纳米处血液吸收强烈，并提出1210和1320纳米对于所有皮肤类型的LASH疗法都是很好的折衷选择。
1210和1320纳米波长被黑色素吸收较少，可确保整个皮肤外植体厚度的温度均匀性。它们在高效LASH疗法中的可能应用现在应通过前瞻性体内研究来证实。
