Surgery – Instruments – Electrical application
Reexamination Certificate
1999-03-19
2001-02-27
Dvorak, Linda C. M. (Department: 3739)
Surgery
Instruments
Electrical application
C606S049000, C606S048000, C606S050000, C606S170000, C606S180000, C604S022000
Reexamination Certificate
active
06193715
ABSTRACT:
GOVERNMENT RIGHTS
Not applicable.
CROSS REFERENCE TO RELATED APPLICATIONS
Not applicable.
BACKGROUND OF THE INVENTION
Rotating surgical instruments that mechanically cut, shave, abrade and drill hard or soft tissue are well known in the art and have proven, over time, to be quite useful. Such tools can be used in open or closed surgical procedures to remove affected tissue. Typical rotating instruments used in these procedures include surgical drilling instruments, such as bone drills, and other rotating mechanical cutting and shaving devices, such as morcellators and power shavers.
Conventional power shavers include an inner rotatable drive shaft having an abrading element at a distal end. The drive shaft seats within a central lumen of the shaver housing such that the abrading element is exposed at the distal end. The drive shaft couples to a motor which imparts rotary movement to the shaft. The power shaver mechanically cuts or shaves affected tissue by the direct mechanical contact of the abrading element with the tissue.
One drawback of such devices is that the abrading edge of the instrument must be extremely sharp to enable effective mechanical cutting of the tissue. During the course of the surgical procedure, however, the abrading or cutting edge of the rotating tool tends to dull, thereby decreasing the cutting performance of the tool. When this occurs, the cutting tool must be replaced. The need for frequent replacement of the abrading portion of the device increases the overall time necessary to conduct the surgical procedure while concomitantly increasing the cost of delivering the medical services and in stocking the replacement components for the medical device.
There thus exists a need in the art for rotary surgical devices that are able to provide effective cutting and abrading of tissue while minimizing or eliminating the need to replace selected components, such as the abrading element, of the device. In particular, it would be useful to provide an adapter device to convert such mechanical surgical tools to electrosurgical tools.
The use of mechanical surgical devices can sometimes lead to undesirable bleeding, which must often be controlled using a separate device. It would also be useful to provide a device that enables a mechanical surgical tool to be used in a manner that it can provide a hemostasis effect.
SUMMARY OF THE INVENTION
The present invention pertains to an electrosurgical adapter assembly to convert a mechanical apparatus that includes a rotary, tissue affecting device in the form of one or more rotating blades, a rotating drill, or a rotating shaving/abrading device, so that its tissue-cutting end serves as one electrode of a bipolar electrosurgical tool. The bipolar electrode action effectively cuts tissue at the surgical site without relying solely upon the mechanical cutting action of the tissue affecting device. The rotary surgical device can be in a form such that it is suitable for use in open or closed surgery. The term “closed surgery” is intended to include arthroscopic, endoscopic, hysteroscopic, laparoscopic, and resectoscopic surgical techniques. Closed surgical techniques typically utilize elongated instruments which are inserted into the patient's body through a small incision or a natural orifice, to allow a secondary instrument easy access to the surgical site. A variety of such surgical devices are well known in the art and are well described in the patent literature. Representative devices are described in U.S. Pat. No. 4,842,578 (Johnson et al.), U.S. Pat. No. 5,411,514 (Fucci et al.) and U.S. Pat. No. 5,492,527 (Glowa et al.).
In its basic configuration, the electrosurgical adapter device of the present invention attaches to a rotating, tissue affecting device having a distal, tissue contacting end which serves as an active, mechanically-operated implement for cutting tissue, and provides a mounting block and a sheath extension assembly which are operative to interconnect a pair of electrosurgical energy contacts or leads to energize, on the one hand, the mechanical cutting tool, and on the other hand, an electrode band which is included in the sheath extension and positioned proximal to or surrounding an exposed region of the distal end of the cutting tool. The actual shape and structure of the mechanical cutting device will depend upon the purpose for which the device is to be used. For example, rotating cutting devices and arthroscopic shaving devices are well known in the art and the structure of such devices can be assumed. The rotating, tissue affecting device also includes a proximal end, usually in the form of an elongate drive shaft, which fits within an outer cannula. The cannula and drive shaft typically form co-acting portions of the cutter, and may constitute a disposable assembly. The cannula can form part of an arthroscope, endoscope, hysteroscope, laparoscope, or resectoscope surgical tool as is well known in the art. The adapter device has a shape corresponding to the cannula/cutter shape of the basic mechanical surgical tool.
The adapter includes electrical contacts that electrically connect at one end to outputs of a remote electrosurgical generator and at their other end connect, respectively, to a conductive body portion of the tissue affecting device, and to an electrode extension carried in the adapter sheath fitted over the outer cannula assembly of the tissue affecting device. The contacts energize the mechanical cutting assembly and thus the distal abrading end by transferring cutting energy from the electrosurgical generator to the drive shaft or cannula, on the one hand, and to a distal electrode which is maintained electrically insulated therefrom and is exposed for a small area proximal to or surrounding the cutter at the distal end.
The adapter of the present invention thus converts a simple mechanical tissue cutting device to a bipolar electrosurgical device, or may be used to convert a monopolar electrosurgical device to bipolar operation. When applied to a simple mechanical cutting device, bipolar operation is achieved between the distal end of the rotating, tissue affecting device and/or its surrounding cannula which serves as one energy delivering electrode, and a second electrode carried in an insulating sheath that fits over the cannula. When applied to adapt a monopolar cutting device to bipolar operation, the adapter adds a second electrode carried in an insulating sheath that insulates the electrode from the cannula and positions it so a current path is formed through tissue in a band surrounding an exposed region at the distal end of the cannula.
During closed surgical procedures it is sometimes necessary to supply a fluid to a surgical site in order to distend the surgical area and to improve visibility for the surgeon. The present system converts cutting tools to bipolar electrosurgical operation, allowing use of an isotonic solution (e.g., saline or Ringer's solution) to distend the surgical site, rather than a non-ionic solution. The patient, therefore, is not exposed to potentially dangerous electrolytic imbalances associated with absorption of non-ionic solution into the patient's bloodstream, and the localization of current paths at the cutting locus prevents the ionic solution from degrading the electrosurgical current paths.
A preferred adapter construction readily configured to convert diverse mechanical cutting instruments includes a mounting block that is adapted to mount to the instrument, for example with a sliding bushing or clamp that connects over the existing cannula and establishes electrical connection to the instrument body. An insulated sheath is carried by the mounting block and extends over the cannula to provide an electrical barrier. The sheath contains a further conductor, which may be a conductive layer extending in or on the sheath, that is exposed at its distal end to form a second electrosurgical electrode for defining current paths in a small region of tissue at the cutting end of the tool. Preferably, the mounting block holds an RF
Allaire Kevin M.
Lemire Kevin P.
Nardella, Sr. Paul C.
Wrublewski Thomas A.
Dvorak Linda C. M.
Medical & Scientific, Inc.
Nutter & McClennen & Fish LLP
Ruddy David M.
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