The clinical effects of a laser or IPL device begin when a target tissue absorbs their energy. In most situations, the absorbed energy is converted to heat, which then destroys the target tissue (chromophore). While the epidermal melanin cannot be shielded or prevented from absorbing laser or IPL radiation, tissue injury may be minimized or eliminated by cooling the skin in precise fashion. Cooling the skin at time of laser or IPL surgery creates a thermal gradient allowing heat to leave the melanosomes before they are destroyed. Thus, the epidermis is relatively protected, while the clinical goal of closing dermal blood vessels is still achieved.
At first glance, cooling the skin seems like an obvious and simple task; more careful study raises some challenging questions. How can the skin be cooled most effectively? Which agent should be used? How long should the coolant be in contact with skin? Should the skin be cooled before, during and/or after treatment?
If the coolant decreases dermal temperature, the targeted vessels will be "protected" in the same manner as the epidermal melanin, and the laser's effectiveness will be diminished. In contrast, inadequate epidermal cooling will limit the intensity of treatment that may be administered and may produce blistering, hypo-pigmentation, and scarring.
Preoperative treatment with ice packs, refrigerated water-based gels, ice-gel slurries and forced air devices all have been used to cool the epidermis. Each of these techniques is inexact, unpredictable, and uncomfortable to the patients.
A superior option is a device with a reservoir that cools water to 4 degrees C before pumping it through a hand piece with a sapphire window. The hand piece is applied to the skin, and the laser or IPL energy beams are passed through the sapphire window.
While this device may be effective, it has some drawbacks. First, the temperature of the water in the reservoir, as opposed to skin temperature, is regulated, Second, the hand piece is connected to the reservoir by plastic tubing; leaking water from the tubing or reservoir, while not frequent, is not uncommon.
The best solution to controlled skin cooling is offered by a device that uses an environmentally safe fluorocarbon to cool a light shield device called a CryoJacket. This CryoJacket contains a sapphire window through which the laser or IPL light energy passes. The UNIQUE FEATURE of this device is that it uses a THERMISTOR to MONITOR the TEMPERATURE CONTINUOUSLY at the skin's surface. Similar to adjusting a thermostat in the home, the device self-regulates to maintain a constant epidermal temperature.
This FDA cleared device is known as the DermaCool and extension of which is EpiCool. When the EpiCool is used in conjunction with a laser or IPL device, patients experience less pain, and may be treated at higher fluences, and may achieve improved clinical results without a significantly increased risk of complications.