Surgery – Instruments – Electrical application
Reexamination Certificate
2001-04-17
2004-06-08
Cohen, Lee (Department: 3739)
Surgery
Instruments
Electrical application
C606S032000, C604S035000, C607S099000, C607S113000, C128S898000
Reexamination Certificate
active
06746447
ABSTRACT:
The present invention is a continuation-in-part of U.S. patent application Ser. No. 09/766,168, filed Jan. 19, 2001, which claims priority from U.S. Provisional Patent Application No. 60/233,345 filed Sep. 18, 2000, and is a continuation-in-part of U.S. patent application Ser. No. 09/709,035 filed Nov. 8, 2000, which claims priority from U.S. Provisional Patent Application No. 60/210,567 filed Jun. 9, 2000, and is a continuation-in-part of U.S. patent application Ser. No. 09/197,013, filed Nov. 20, 1998 now U.S. Pat. No. 6,296,638, which is a continuation-in-part of U.S. patent application Ser. No. 09/010,382, filed Jan. 21, 1998, now U.S. Pat. No. 6,190,381 which is a continuation-in-part of U.S. patent application Ser. No. 08/990,374, filed on Dec. 15, 1997, which is a continuation-in-part of U.S. patent application Ser. No. 08/485,219, filed on Jun. 7, 1995, now U.S. Pat. No. 5,697,281, which is a continuation-in-part of PCT International Application, U.S. National Phase Ser. No. PCT/US94/05168, filed on May 10, 1994, now U.S. Pat. No. 5,697,909, which was a continuation-in-part of U.S. patent application Ser. No. 08/059,681, filed on May 10, 1993, the complete disclosures of which are incorporated herein by reference for all purposes. The present invention also is related to Provisional Patent Application 60/062,996 filed on Oct. 23, 1997.
The present invention is related to commonly assigned co-pending Provisional Patent Application 60/062,997 filed on Oct. 23, 1997, non-provisional U.S. patent application Ser. No. 08/977,845, filed Nov. 25, 1997, which is a continuation-in-part of application Ser. No. 08/562,332, filed Nov. 22, 1995, the complete disclosures of which are incorporated herein by reference for all purposes. The present invention is also related to U.S. patent application Ser. Nos. 09/109,219, 09/058,571, 08/874,173 and 09/002,315, filed on Jun. 30, 1998, Apr. 10, 1998, Jun. 13, 1997, and Jan. 2, 1998, respectively and U.S. patent application Ser. No. 09/054,323, filed on Apr. 2, 1998, U.S. patent application Ser. No. 09/010,382, filed Jan. 21, 1998, and U.S. patent application Ser. No. 09/032,375, filed Feb. 27, 1998, U.S. patent application Ser. Nos. 08/977,845, filed on Nov. 25, 1997, Ser. No. 08/942,580, filed on Oct. 2, 1997, U.S. application Ser. No. 08/753,227, filed on Nov. 22, 1996, U.S. application Ser. No. 08/687792, filed on Jul. 18, 1996, the complete disclosures of which are incorporated herein by reference for all purposes. The present invention is also related to commonly assigned U.S. Pat. No. 5,683,366, filed Nov. 22, 1995, the complete disclosure of which is incorporated herein by reference for all purposes.
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 resect, coagulate, ablate, and aspirate cartilage, bone and other tissue, such as sinus tissue, adipose tissue, or meniscus, cartilage, and synovial tissue in a joint. The present invention also relates to apparatus and methods for aggressively removing tissue at a target site by a low temperature ablation procedure, and efficiently aspirating products of ablation from the target site. The present invention further relates to an electrosurgical probe having a plurality of working zones distinguishable from each other on the basis of their aspiration and/or ablation rate.
Conventional electrosurgical methods generally reduce patient bleeding associated with tissue cutting operations and improve the surgeon's visibility. These electrosurgical devices and procedures, however, suffer from a number of disadvantages. For example, monopolar electrosurgery methods generally direct electric current along a defined path from the exposed or active electrode through the patient's body to the return electrode, which is externally attached to a suitable location on the patient's skin. In addition, since the defined path through the patient's body has a relatively high electrical impedance, large voltage differences must typically be applied between the active and return electrodes to generate a current suitable for cutting or coagulation of the target tissue. This current, however, may inadvertently flow along localized pathways in the body having less impedance than the defined electrical path. This situation will substantially increase the current flowing through these paths, possibly causing damage to or destroying tissue along and surrounding this pathway.
Bipolar electrosurgical devices have an inherent advantage over monopolar devices because the return current path does not flow through the patient beyond the immediate site of application of the bipolar electrodes. In bipolar devices, both the active and return electrode are typically exposed so that they may both contact tissue, thereby providing a return current path from the active to the return electrode through the 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.
Another limitation of conventional bipolar and monopolar electrosurgery devices is that they are not suitable for the precise removal (ablation) of tissue. For example, conventional electrosurgical cutting devices typically operate by creating a voltage difference between the active electrode and the target tissue, causing an electrical arc to form across the physical gap between the electrode and tissue. At the point of contact of the electric arcs with tissue, rapid tissue heating occurs due to high current density between the electrode and tissue. This high current density causes cellular fluids to rapidly vaporize into steam, thereby producing a “cutting effect” along the pathway of localized tissue heating. The tissue is parted along the pathway of vaporized cellular fluid, inducing undesirable collateral tissue damage in regions surrounding the target tissue site.
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 long enough period of time to energize the electrode and conduct current through the tissue.
The use of electrosurgical procedures (both monopolar and bipolar) in electrically conductive environments can be further problematic. For example, many arthroscopic procedures require flushing of the region to be treated with isotonic saline, both to maintain an isotonic environment and to keep the field of view clear. However, the presence of saline, which is a highly conductive electrolyte, can cause shorting of the active electrode(s) in conventional monopolar and bipolar electrosurgery. Such shorting causes unnecessary heating in the treatment environment and can further cause non-specific tissue destruction.
Conventional electrosurgical cutting or resecting devices also tend to leave the operating field cluttered with tissue fragments that have been removed or resected from the target tissue. These tissue fragments make visualization of the surgical site extremely difficult. Removing these tissue fragments can also be problematic. Similar to synovial tissue, it is difficult to maintain contact with tissue fragments long enough to ablate the tissue fragments in situ with conventional devices. To solve this problem, the surgical site is periodically or continuously aspirated during the procedure. However, the tissue fragments often clog the aspiration lumen of the suct
Davison Terry S.
Ormsby Theodore C.
Willink Christopher L.
Arthrocare Corporation
Batt Richard R.
Cohen Lee
Raffle John T.
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