Surgery – Instruments – Electrical application
Reexamination Certificate
1998-12-03
2001-05-08
Cohen, Lee (Department: 3739)
Surgery
Instruments
Electrical application
C606S041000, C606S050000
Reexamination Certificate
active
06228082
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 vascular disorders, such as, cutaneous vascular lesions, port wine stains, face veins, telangiectasis, spider veins, birth marks and the like.
A cutaneous vascular lesion, such as telangiectasis or spider capillaries of the lower extremities, is a condition where previously microscopic blood vessels have become dilated. They are visible through the skin appearing as red, blue or purple variably tortuous lines or patches. The causes of this abnormal enlargement of vessels are not fully understood, and although they are of little medical consequence, their cosmetic significance can be great.
The most common treatment used for cutaneous vascular lesions is sclerotherapy, which entails the intravascular injection of one of a variety of agents into the abnormal blood vessels. The injected substance injures the interior walls of the capillary causing it to shrink or disappear. Unfortunately, this treatment can be painful, only partially effective, and usually requires about one to two months waiting before improvement can be seen. In addition, undesirable side effects can occur, such as echymotic or hyperpigmented marks, which may take months to completely fade away.
In the treatment of vascular lesions, a variety of different lasers (e.g., CO2, Argon, tunable dye, pulsed dye, KTP, Nd/Yag) have been used to irradiate the surface of the skin. The laser energy penetrates through the skin and is absorbed by the constituents 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. In addition, if the laser energy is delivered over too long a period, significant thermal damage will occur in regions beyond the vein being treated. Moreover, the interaction between laser light and melanin pigments in the epidermis that overlies the target vessels can cause long term hyperpigmentation, persistent scabs and sometimes permanent scarring.
SUMMARY OF THE INVENTION
The present invention provides systems, apparatus and methods for selectively applying electrical energy to blood vessels within the body, and is particularly useful for treating vascular disorders.
In one aspect of the invention, a method for treating a discolored blood vessel in tissue under the surface of the skin is provided. In this method, one or more active electrode(s) are positioned in close proximity to a target region of the blood vessel, and a sufficient high frequency voltage is applied to the electrode terminal(s) to cause thermal damage to a target region within the blood vessel. The thermal injury causes the vessel to shrink, or to thrombose and collapse, so that blood flow through the vessel is restricted or completely interrupted. Preferably, the vessel is injured with minimal thermal energy being applied to the surrounding tissue, which prevents the tissue discoloration or scarring associated with prior art thermal processes. The electrode terminal(s) may be positioned on the external surface of the skin, or they may be introduced through a percutaneous penetration in the outer skin surface to the blood vessel. In the latter embodiment, the percutaneous penetration may be formed by advancing one or more needle electrodes through the outer surface of the skin to the target region of the vessel. Alternatively, this percutaneous penetration may be generated by applying sufficient electrical energy to the electrode terminal(s) to remove or ablate a portion of the outer skin surface. In this latter embodiment, the electrode terminal(s) are advanced axially through the skin to volumetrically remove or ablate a hole or channel from the skin surface to the blood vessel. A more complete description of systems and methods for boring channels through tissue with RF energy can be found in commonly assigned U.S. Pat. No. 5,683,366, the complete disclosure of which is incorporated herein by reference.
In a specific embodiment, a needle electrode is inserted through the patient's skin such that a distal portion of the needle electrode is located in close proximity to the target region of the blood vessel. High frequency voltage is then applied between the needle electrode and a return electrode to effect coagulation and/or necrosis of the blood vessel. In the representative embodiment, the needle electrode is an insulated acupuncturesized needle having a diameter in the range of about 0.05 to about 2.0 mm, preferably less than 1 mm in diameter. A selected length of the distal portion of the needle is exposed (e.g., typically less than about 3 mm and preferably less than abut 0.5 mm) to allow current to flow from needle to the surrounding tissue and blood vessel. The needle is inserted through the patient's skin to the target region of the blood vessel, and high frequency voltage is applied such that a current flows from the exposed portion of the needle through the target region and to the return electrode.
In this aspect of the invention, the return electrode may be positioned on the surface of the patient's skin, or it may be introduced through the skin to a location in close proximity to the target region of the blood vessel. In the latter embodiment, the return electrode may be located on the insulated needle (e.g., as a second exposed portion spaced and electrically isolated from the active exposed portion), or it may be part of a separate instrument. In the representative embodiment, the return electrode comprises a thin, insulated, conductive needle having an inner lumen for receiving the active needle electrode, and an exposed distal portion for completing the current return path from the active needle electrode. The active needle electrode is preferably axially movable relative to the return electrode such that the distance between the two exposed portions of the electrodes can be varied during the procedure. This allows the surgeon to control the zone of necrosis around the target region. The bipolar modality of the present invention confines the electric currents to the target region, minimizing thermal injury to surrounding skin tissue.
In the representative embodiment, the return electrode needle includes a fluid lumen for delivering fluid to the target site. Preferably, the return electrode is a hollow needle having a central lumen for fluid delivery and for receiving the active electrode needle. In one embodiment, electrically conductive fluid, such as isotonic saline, is delivered to the target site to decrease the tissue resistance around the target site. This will increase the effectiveness of the device by reducing tissue heating around the target site, and by further confining the electric current to the target, thereby reducing collateral tissue damage. In another embodiment, a local anesthetic is delivered alone, or in combination with a conductive fluid, to the target region such that the procedure may be performed in the doctor's office under local anesthesia. The present invention may be used in combination with a tumescent technique for delivering a relatively large volume of a dilute solution of a local anesthetic agent and/or a vasoconstrictor agent to the target site. The anesthetic and vasoconstrictor agents may be dilute in a solution of, for example, electrically conductive fluid.
The system may optionally include a temperature controller coupled to one or more temperature sensors at or near the distal end of the active or return electrode(s). The controller adjusts the output voltage of the power supply in response to a temperature set point and the measured temperature value. The temperature sensor may be, for example, a thermocouple, located on the
Baker Michael A.
Brunell Stephen M.
Underwood Ronald A.
ArthroCare Corporation
Cohen Lee
Raffle John T.
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