Method and apparatus for treating wrinkles in skin using radiation

Abstract

A method for treating wrinkles in skin involves the use of a beam of pulsed, scanned or gated continuous wave laser or incoherent radiation. The method comprises generating a beam of radiation, directing the beam of radiation to a targeted dermal region between 100 microns and 1.2 millimeters below a wrinkle in the skin, and thermally injuring collagen in the targeted dermal region. The beam of radiation has a wavelength of between 1.3 and 1.8 microns. The method may include cooling an area of the skin above the targeted dermal region while partially denaturing the collagen in the targeted dermal region. The method may also include cooling an area of the skin above the targeted dermal region prior to thermally injuring collagen in the targeted dermal region.

Description

FIELD OF THE INVENTION[0001]The invention relates generally to the treatment of wrinkles in human skin using radiation. In particular, the invention relates to a method for treating wrinkles in human skin using a beam of laser or incoherent radiation to cause thermal injury in the dermal region of the skin sufficient to elicit a healing response that produces substantially unwrinkled skin.BACKGROUND OF THE INVENTION[0002]Undesired wrinkles in skin are commonly seen in dermatologic practice. Wrinkles in skin may be caused by age and by exposure to the sun's ultraviolet rays. Human skin consists mainly of two layers: the top layer of skin known as the epidermis; and the layer beneath the epidermis known as the dermis. The dermis is primarily acellular and is composed of water, the protein collagen, and glycosaminoglycans. Water constitutes approximately 70 percent of the total weight of the dermis. Collagen constitutes approximately 70 percent of the dry weight of the dermis, and glyc...

AI Technical Summary

Benefits of technology

[0008]The present invention addresses the foregoing problems and provides a method for inducing remodeling of the skin's extracellular matrix by partially denaturing the dermal collagen deeper in the skin, below the surface, while avoiding injury to the epidermis and upper layers of the dermis. The invention offers numerous advantages over existing dermatologic procedures and devices. The surface of the skin remains intact, thereby avoiding the need for dressing wounds; pigmentary disturbances are minimized; and any inflammatory response to the injury is mild and less visually evident.

[0010]More specifically, causing selective thermal injury to the dermis activates fibroblasts which deposit increased amounts of extracellular matrix constituents (i.e., collagen and glycosaminoglycans). These increases in extracellular matrix constituents are responsible for dermal skin rejuvenation and the reduced appearance of wrinkles.

[0011]In one embodiment, the beam of radiation causes partial denaturation of the collagen in the targeted dermal region. The partial denaturation of the collagen accelerates the collagen synthesis process by the fibroblasts and the deposition of new glycosaminoglycans, leading to the elimination or a reduction in the severity of the wrinkle. The method may also include cooling the surface of the skin and epidermal tissue above the targeted dermal region while irradiating the skin. The method may also include cooling the surface of the skin prior to irradiating the skin.

[0013]The invention also relates to an apparatus for treating wrinkles in skin. The apparatus includes a radiation source and a delivery system which includes a cooling system. The radiation source generates a beam of radiation having a wavelength between 1.3 and 1.8 microns. The delivery system directs the beam of radiation to a targeted dermal region between 100 microns and 1.2 millimeters below a wrinkle in the skin. The cooling system cools the epidermal tissue above the targeted dermal region to minimize injury to the surface of the skin.

Problems solved by technology

In addition, the remaining collagen tends to be chaotically oriented as compared to the more organized patterns found in youthful skin.

However, all of these methods disrupt and completely remove the epidermis.

Epidermal destruction and subsequent healing has several undesirable side effects.

These undesirable side effects include prolonged hypopigmentation, hyperpigmentation, erythema and edema.

Hyperpigmentation results in the treated area of the subject's skin turning darker than the surrounding untreated skin.

While generally transient, hypopigmentation can be permanent, and is cosmetically undesirable while it persists.

Also, erythema or redness of the skin may be significant for weeks to months after the procedure, requiring the patients to wear conspicuous amounts of make-up.

However, this technique cannot be effectively used to remove wrinkles in skin by shrinking dermal collagen.

The depths of thermal injury which can be achieved in skin using the wavelengths in this range are therefore limited to the most superficial layer of the skin.

Such superficial injury leads to an inflammatory healing response characterized by prolonged visible edema and erythema, as well as the possibility for long lasting pigmentary disturbances.

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