Electrosurgical systems and methods for removing and modifying tissue

Abstract

The present invention provides systems, apparatus and methods for selectively applying electrical energy to body tissue in order to ablate, contract, coagulate, or otherwise modify a tissue or organ of a patients. An electrosurgical apparatus includes an electrode support bearing an active electrode in the form of a plasma blade or hook having an active edge and first and second blade sides. The active edge is adapted for severing a target tissue via localized molecular dissociation of tissue components. The first and second blade sides are adapted for engaging against, and coagulating, the severed tissue. A method of the present invention comprises positioning an electrosurgical probe adjacent to the target tissue so that a blade- or hook-like active electrode is brought into at least close proximity to the target tissue in the presence of an electrically conductive fluid. A high frequency voltage is applied between the active electrode and a return electrode to effect cool ablation or other modification of the target tissue. During application of the high frequency voltage, the electrosurgical apparatus may be translated, reciprocated, or otherwise manipulated such that the active edge is moved with respect to the tissue. The present invention volumetrically ablates or otherwise modifies the target tissue with minimal or no damage to surrounding, non-target tissue.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 10 / 339,470, filed Jan. 9, 2003, which is a divisional of U.S. patent application Ser. No. 09 / 780,745, filed Feb. 9, 2001, now U.S. Pat. No. 6,770,071, which claims the benefit of U.S. Provisional Patent Application No. 60 / 182,751 filed Feb. 16, 2000. application Ser. No. 09 / 780,745 is also a continuation-in-part of U.S. patent application Ser. No. 09 / 162,117, filed Sep. 28, 1998, now U.S. Pat. No. 6,117,109, which is a continuation in part of U.S. patent application Ser. No. 08 / 977,845, filed Nov. 25, 1997, now U.S. Pat. No. 6,210,402, which is a continuation-in-part of U.S. patent application Ser. No. 08 / 562,332, filed Nov. 22, 1995, now U.S. Pat. No. 6,024,733, all of which are herein incorporated by reference for all purposes.[0002]The present invention is also related to commonly assigned U.S. Provisional Patent Application No. 60 / 062,996, filed Oct. 23, 1997, and...

AI Technical Summary

Benefits of technology

The present invention provides systems, methods, and apparatus for using high frequency electrical energy to cut, incise, ablate, or otherwise modify tissue or organs of a patient. The invention is particularly useful for procedures such as harvesting veins and arteries, and dissecting the sternum to access the chest cavity. The high frequency electrical energy is applied through an electrosurgical probe with active electrodes that are designed for cutting tissue. The use of the invention allows for precise control over the depth of hemostasis (the point at which the tissue is cut) and minimal damage to surrounding tissue. The invention also allows for simultaneous coagulation and hemostasis, improving visualization and recovery time for the patient. The invention provides a more efficient and safe method for performing these procedures.

Problems solved by technology

Conventional electrosurgical devices and procedures, however, suffer from a number of disadvantages.

At the point of contact of the electric arcs with the tissue, rapid tissue heating occurs due to high current density between the electrode and the tissue.

Thus, the tissue is parted along the pathway of evaporated cellular fluid, inducing undesirable collateral tissue damage in regions surrounding the target tissue.

This creates the potential danger that the electric current will flow through undefined paths in the patient's body, thereby increasing the risk of unwanted electrical stimulation to portions of the patient's body.

This current, however, may inadvertently flow along body paths having less impedance than the defined electrical path, which will substantially increase the current flowing through these paths, possibly causing damage to or destroying surrounding tissue.

One drawback with this configuration, however, is that the return electrode may cause tissue desiccation or destruction at its contact point with the patient's tissue.

The close proximity of these electrodes generates the danger that the current will short across the electrodes, possibly impairing the electrical control system and / or damaging or destroying surrounding tissue.

In addition, conventional electrosurgical methods are generally ineffective for ablating certain types of tissue, and in certain types of environments within the body.

For example, loose or elastic connective tissue, such as the synovial tissue in joints, is extremely difficult (if not impossible) to remove with conventional electrosurgical instruments because the flexible tissue tends to move away from the instrument when it is brought against this tissue.

Since conventional techniques rely mainly on conducting current through the tissue, they are not effective when the instrument cannot be brought adjacent to, or in contact with, the elastic tissue for a sufficient period of time to energize the electrode and conduct current through the tissue.

Vascular complications produced by atherosclerosis, such as stenosis, aneurysm, rupture, or occlusion, increase the likelihood of angina, stroke, and heart attacks.

However, such methods suffer from numerous drawbacks.

For example, the longitudinal incision in the sternum often results in bone bleeding, which is difficult to stop.

The bone bleeding can produce a high degree of trauma, a larger risk of complications, an extended hospital stay, and a painful recovery period for the patient.

A number of disadvantages inherent in conventional electrosurgical devices have been set forth hereinabove.

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