Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1999-07-29
2001-10-09
Arbes, Carl J. (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C606S048000, C606S051000, C606S052000
Reexamination Certificate
active
06298550
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
N/A
BACKGROUND OF THE INVENTION
Electro-surgical forceps have a pair of resilient blades or arms which are used for grasping and coagulating tissue. The forceps may be monopolar or bipolar. In monopolar forceps, the blades are welded or otherwise joined to form an electrode in electrical communication with an electrical generator. Current flows from the active electrode through the patient's tissue to a dispersive electrode in contact with the patient's skin (which may be at some distance from the forceps) and back to the generator. In bipolar forceps, each blade of the pair comprises an electrode in communication with an electrical generator. Current flows from one blade through the tissue to the other blade.
In some instances, tissue may adhere or stick to the tips of the blades. If sticking occurs, the surgeon must pull on the forceps to release it from the tissue, possibly causing further bleeding and requiring that the forceps be cleaned. It is known to prevent or minimize such sticking of tissue to electrosurgical forceps by manufacturing the blades of the forceps from nickel. See, for example, U.S. Pat. No. 5,196,009. During high power operation, some eschar buildup and some sticking of the tissue to the tips still may occur. Another known manner of preventing or minimizing sticking is to form the blades from a metal or metal alloy having a relatively high thermal conductivity, such as copper, which is able to transfer heat away from the tips of the blades. By keeping the tissue cooler, for example, below the boiling point of water, coagulation is able to occur without sticking of the tissue. See, for example, U.S. Pat. No. 4,492,231.
BRIEF SUMMARY OF THE INVENTION
An electro-surgical forceps are provided which minimize or prevent sticking to the tissue of a patient and eschar buildup. The forceps include a pair of blade members extending from an insulated cap portion. At least one of the blade members is electrically conducting. Within the cap portion, the blades are electrically connected to terminals for connection to an electrical generator.
The blade members include an inner layer of copper or copper alloy having a thickness sufficient to dissipate heat generated at the tip to prevent sticking of tissue to the forceps during use and to allow operation of the forceps at a lower power level. An outer covering of a strong, biocompatible metal or metal alloy covers the surfaces of the inner copper layer to prevent exposure of the copper. Preferably, the outer covering comprises a first nickel layer metallurgically bonded to one side of the inner copper layer and a second nickel layer metallurgically bonded to an opposite side of the inner copper layer. The thickness of the nickel layers is sufficient to withstand the forming process, to minimize or prevent delamination from the inner copper layer, and to minimize or prevent exposure of the inner copper layer through the nickel layers.
An insulating material is provided over the blade members from the cap portion to a location adjacent the tip of the blade member. A biocompatible plating, typically of gold, preferably encapsulates the tip to provide additional electrical and thermal conductivity and additional coverage of the inner copper layer on the edges.
The nickel layers are more biocompatible with human tissue than copper and are thus preferable for contact with the tissue, as well as providing additional non-stick capabilities. Also, the nickel layers have a thickness significantly greater than the thickness of a coating formed by a plating process. This greater thickness ensures that the nickel layers are able to withstand the forming process and are unlikely to wear away through use or during cleaning of the forceps, as is the case with a plating. Also, the process of metallurgically bonding the nickel layers to the copper layer of the present invention further minimizes the likelihood that the nickel layers may delaminate or separate from the copper layer. Further, nickel or nickel alloys are hard metals which also render them suitable for withstanding the forming process of the present invention and for providing a wear resistant outer covering.
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Arbes Carl J.
Kirwan Surgical Products, Inc.
Weingarten, Schurgin Gagnebin & Hayes LLP
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