Surgery – Instruments – Light application
Reexamination Certificate
1997-10-08
2001-01-23
Dvorak, Linda C. M. (Department: 3739)
Surgery
Instruments
Light application
C606S009000, C606S003000, C606S010000
Reexamination Certificate
active
06176854
ABSTRACT:
TECHNICAL FIELD
The present invention relates to methods and procedures for the amelioration of cosmetic flaws and the like by the application of laser energy to a selected target region or site. The present invention is useful in the practice of surgery, especially plastic and cosmetic surgery, as well as dermatology. The present invention is especially suitable for minimally invasive surgical treatments in which a percutaneous approach is desired.
BACKGROUND OF THE INVENTION
Biological tissue comprises cells embedded in a primarily proteinaceous extracellular matrix. Collagen is one of the predominant proteins found in the extracellular matrix. Collagen can be altered by the application of thermal energy to become denatured and act as a biological glue. Thermal energy can also cause collagen fibers to become cross-linked, reducing the volume of the thermally treated collagen. The thermal effect may be conveniently produced by the interaction of laser generated light energy with tissue. Laser energy of the appropriate wavelength, energy and geometry can thus be used to weld together opposed tissue surfaces and shrink collagen-containing tissues.
The use of laser devices in various types of surgery is known. Such devices cause thermal coagulation and/or ablation of tissue by emission of a predetermined level of laser energy for a predetermined time. The unwanted tissue can be coagulated to the desired depth by laser energy at low energy density, or ablated by subjecting the tissue to a higher level of energy density. However, when laser energy is applied to the skin from an external source, erythema or sun-burning frequently occurs. The erythema can take weeks or months to subside, and discoloration or scarring of the skin may be a lasting result.
Several plastic surgery procedures involve the surgical removal of subcutaneous fat and excess skin and the tightening of the remaining skin. Such procedures include meloplasty (face lifts), eyebrow lifts and blepharoplasty for removal of bags under the eyes (dermochalasis and blepharochalasis). Beyer, C. K., Baggy lids,
Int. Ophthalmol. Clin
., 10: 47-53 (1970). Traditional surgical approaches require cutting and removing excess skin and fat using incisions often centimeters in length. These approaches are subject to potential complications such as hemorrhage, hematoma, infection and removal of too much skin or fat (overcorrection). Kohn, R.,
Textbook of Ophthalmic Plastic and Reconstructive Surgery
, pp. 177-191, 186, Lea & Febiger, Philadelphia (1988). As an example, surgical procedures for blepharoplasty are complex. Inappropriate or poorly performed surgery may result in an adverse cosmetic result, or may place the patient at risk for developing vision-threatening complications. Custer, P. L., Lower eyelid blepharoplasty, in Bosniak, S., editor,
Principles and Practice of Ophthalmic Plastic and Reconstructive Surgery
, pp. 617-625, 624, W. B. Saunders, Philadelphia (1996).
Lasers have been employed in cosmetic and reconstructive surgery. The Nd:YAG laser has been used to make incisions in the skin for face lifts (meloplasty) and for removal of bags under the eyes by blepharoplasty. Apfelberg, D. B., YAG laser meloplasty and blepharoplasty,
Aesth. Plast. Surg
. 19: 231-235 (1995). However, the Nd:YAG laser's continuous wave energy may be overly thermal and cause an excessively deep zone of penetration (about 4000 &mgr;m). The CO
2
laser has been employed in blepharoplasty using the transconjunctival approach. David, L. M., The laser approach to blepharoplasty,
J. Dermatol. Surg. Oncol
. 14: 741-235 (1988). While the use of laser energy has been reported to reduce bleeding during surgery and reduce pain during healing, a large incision is still required. Morrow, D. M., and Morrow, L. B., CO
2
laser blepharoplasty. A comparison with cold-steel surgery,
J. Dermatol. Surg. Oncol
., 18: 307-313 (1992). The only advantage provided by the described laser technique was less swelling after surgery.
What is needed is a method of plastic surgery using a laser that provides more desirable tissue effects and which can also be used in a minimally invasive percutaneous approach.
SUMMARY OF THE INVENTION
A percutaneous method for the treatment of skin and subcutaneous tissue by means of a laser device capable of emitting pulses of light energy of an appropriate wavelength with relatively short pulse widths, at relatively low energy per pulse and relatively rapid pulse repetition rates is provided by the present invention. Light energy characterized by such parameters is applied subcutaneously to tissues underlying the skin. The method is useful for the practice of surgery, especially plastic and cosmetic surgery as well as dermatology. The method is non-invasive or minimally invasive and well suited for outpatient therapy. In particular, application of the laser energy directly to the tissue beneath the skin eliminates or reduces the erythema that can result when laser energy is applied to the skin from outside the body.
The method of the present invention is especially suitable for several procedures used in plastic and cosmetic surgery as well as dermatology. Procedures for which the method of the present invention can be used include, inter alia, the removal of pigmentation, such as lentigines (age spots), hyperpigmentation, lentigo (freckles), caf{acute over (e)}-au-lait macules, actinic keratosis, melasma, and tattoos (body or facial). The method of the present invention can also be used for the removal of plantar warts, chin reshaping via the percutaneous laser melting or desiccation of fat, amelioration of turkey neck, and the treatment of some dilated blood vessels associated with rosacea. The method of the present invention is also suitable for coagulation of spider veins (<1 mm), removal of keloid scars, coagulation of varicose veins (>1 mm), reshaping of the upper lip, reshaping of the eyelids, permanent ablation of the hair follicle to permanently prevent hair regrowth and some types of otoplasty. The method of the present invention is also suitably used for the treatment of various cutaneous vascular lesions, such as port wine stains, hemangiomas, and telangiectasias, including those of the face and the leg.
The method of the present invention can also be used for plastic surgery treatments such as skin resurfacing, removal of perioral, periorbital and ear lobe wrinkles, treatment of nasal labial folds, perioral fat pads and marionette lines, lip lift, neck lift, eyebrow lift, lipolysis (of upper and lower eyelids, cheeks, abdomen, thighs), blepharoplasty, rhinoplasty, treatment of polly beak and internal weir (nostril reduction). Scars that can be treated using the method of the present invention include acne scars, keloids, chicken pox scars, stretch marks (striae), hypertrophic scars, and skin graft hypertrophy as well as pits and depressions. In addition, the method of the present invention is also suitable for burn debridement, and for the treatment of corns, papilloma (warts, condylomas, polyps) and skin cancer, including basal cell carcinoma.
A pulsed or continuous wave holmium:YAG laser, holmium:YSGG laser or other laser emitting light energy at a wavelength of about 1800 micrometers to about 2200 micrometers (“holmium laser”) may be converted, in accordance with the present invention, to produce pulses of variable pulse-width at various energy levels. The light energy from a holmium laser has an ideal depth of penetration into tissue, about 250 to 400 &mgr;m. The holmium laser is a preferred light energy source because light energy obtained therefrom has the property of being able to cause cross-linking of collagen proteins, lysis of fat and bloodless incisions, primarily due to the wavelength of light emitted.
Energy from a relatively low power, short pulse-width, high repetition rate holmium laser, applied percutaneously through an optical fiber, can avoid burning or charring the tissue while accomplishing the desired beneficial physiologic effect. At lower energy densities, the collagen component of t
Dvorak Linda C. M.
Harris-Ogugua Sonya
Olson & Hierl Ltd.
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