Surgery – Instruments – Electrical application
Reexamination Certificate
1997-11-25
2001-04-03
Cohen, Lee (Department: 3739)
Surgery
Instruments
Electrical application
C606S041000, C607S099000, C604S114000
Reexamination Certificate
active
06210402
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of electrosurgery, and more particularly to surgical devices and methods which employ high frequency electrical energy to treat a patient's skin, including skin resurfacing procedures, the removal of pigmentations, vascular lesions, scars and tattoos, hair removal and/or transplant procedures, treatment of skin cancer, skin rejuvenation (e.g., wrinkle removal) and the like.
In early dermatology procedures, cosmetic surgeons often employed chemical peels and/or dermabrasion techniques to remove outer layers of the patient's skin to rejuvenate wrinkled skin or to remove skins disorders, such as acne, lesions, early skin cancer, etc. These dermabrasion and chemical procedures, however, are difficult to control, requiring great surgical skill. In addition, these somewhat inelegant techniques often cause excessive bleeding, collateral tissue damage and patient discomfort.
In an effort to overcome some of the limitations of dermabrasion and chemical peels, lasers have been developed for use in cosmetic surgery. Lasers have improved the accuracy of skin resurfacing procedures, and they have reduced collateral damage to the tissue surrounding and underlying the treatment site. In laser dermatology applications, a handpiece is typically used to guide the output of a laser to the patient's skin, and to form a laser spot of a desired size on the region of the skin which is to be treated. The handpiece is typically attached to one end of an articulated arm which transmits the output of a medical laser (such as CO
2
or Er:YAG lasers) to the handpiece and allows the handpiece a wide range of motion.
Although initially promising, lasers suffer from a number of drawbacks in dermatology procedures. In the first place, laser equipment can be very expensive because of the costs associated with the laser light sources. Moreover, those lasers which permit acceptable depths of necrosis (such as excimer lasers, erbium:YAG lasers, and the like) provide a very low volumetric ablation rate, requiring numerous passes over the same treatment area which amounts to longer procedural times. In addition, erbium:YAG lasers generally do not provide effective hemostasis during the procedure, resulting in excessive bleeding which disrupts the surgeon's view of the treatment site. The CO
2
lasers provide a higher rate of ablation and an increased depth of tissue necrosis than their erbium:YAG counterparts. On the other hand, CO
2
lasers often create significant residual thermal injury to tissue at and surrounding the treatment site, which requires long healing periods for the patient. In addition, CO
2
lasers are associated with much pain and, therefore, require a lot of anesthesia, which increases the cost and length of the procedure.
In the treatment of vascular lesions, lasers are used to irradiate the surface of the skin. The laser energy penetrates through the skin and is absorbed in the blood, which coagulates and collapses the vein. Unfortunately, there are also problems associated with the use of lasers in these procedures. For example, although most of the laser energy passes through the tissue to the vessel, scattering and absorption of the light take place in the tissue. This absorption can cause significant changes in skin coloration and even scarring.
Monopolar electrosurgical instruments have been used to effect electrodessication of abnormalities, such as lesions, skin tags, viral warts, pigment nevi, moles and skin cancer. For example, Conmed Corporation manufacturers a monopolar device, termed the Hyfrecator™ having a single active electrode at the tip of an electrosurgical probe. In these procedures, the skin abnormality is typically removed with a scalpel, and a low voltage is applied to the active electrode in contact with the target tissue to deliver electric current through the tissue and the patient to a dispersive pad or indifferent electrode. The voltage desiccates the remaining abnormal tissue, and coagulates severed blood vessels at the target site. The remaining tissue is then removed with a sponge or similar material. The voltage generally must be low enough to prevent charring and potential scarring of the underlying dermis.
SUMMARY OF THE INVENTION
The present invention provides systems, apparatus and methods for selectively applying electrical energy to structures on the external surface of a patient's body. The systems and methods of the present invention are useful in dermatological procedures, i.e., surface treatment of the patient's outer skin, such as the epidermis and/or the underlying dermis. For example, the present invention is particularly useful for surface tissue ablation on the epidermis and/or collagen shrinkage in the epidermis or dermis, e.g., the removal of pigmentations, vascular lesions (e.g., leg veins), scars, tattoos, etc., and for other surgical procedures on the skin, such as tissue rejuvenation, cosmetic surgery, wrinkle removal, hair removal and/or transplant procedures.
In one aspect of the invention, a method includes positioning one or more electrode terminal(s) on the distal tip of an instrument in close proximity to a target site on an external body surface of the patient. High frequency voltage is applied to the electrode terminal(s) to elevate the temperature of collagen fibers within the tissue at the target site from body temperature (about 37° C.) to a tissue temperature in the range of about 45° C. to 90° C., usually about 60° C. to 70° C., to substantially irreversibly contract these collagen fibers. In a preferred embodiment, an electrically conducting fluid is provided between the electrode terminal(s) and one or more return electrode(s) positioned proximal to the electrode terminal(s) to provide a current flow path from the electrode terminal(s) away from the tissue to the return electrode(s).
The current flow path may be generated by directing an electrically conducting fluid along a fluid path past the return electrode and to the target site, or by locating a viscous electrically conducting fluid, such as a gel, at the target site, and submersing the electrode terminal(s) and the return electrode(s) within the conductive gel. The collagen fibers may be heated either by passing the electric current through the tissue to a selected depth before the current returns to the return electrode(s) and/or by heating the electrically conducting fluid and generating a jet or plume of heated fluid, which is directed towards the target tissue. In the latter embodiment, the electric current may not pass into the tissue at all. In both embodiments, the heated fluid and/or the electric current elevates the temperature of the collagen sufficiently to cause hydrothermal shrinkage of the collagen fibers.
In a specific configuration, the electrode terminal(s) are brought into contact with, or close proximity to, the target tissue so that the electric current passes directly into the tissue to a selected depth. In this embodiment, the return electrode(s) draw the electric current away from the tissue site to limit its depth of penetration into the tissue.
In another aspect of the invention, a high frequency voltage is applied to one or more electrode terminal(s), and a layer of the epidermis is removed from the patient. In some embodiments, the high frequency voltage applied to the electrode terminal(s) creates sufficient heat within the skin to decouple or physically separate the epidermis layer from the underlying papillary dermis. The epidermis layer may then be removed by flushing the treatment site with a fluid, or brushing the epidermis layer away from the treatment site, e.g., with a gauze cloth. In this embodiment, the energy applied to the tissue may be further selected to contract the collagen tissue within the underlying dermis as the epidermis layer is being decoupled or separated therefrom. This method removes the surface layer of the skin, while tightening the underlying dermis to remove wrinkles and rejuvenate the skin.
In other emb
Brunell Stephen M.
Eggers Philip E.
Olsen Phillip M.
Thapliyal Hira V.
ArthroCare Corporation
Cohen Lee
Raffle John T.
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