Surgery – Instruments – Electrical application
Reexamination Certificate
1999-09-22
2001-03-06
Dvorak, Linda C. M. (Department: 3739)
Surgery
Instruments
Electrical application
C606S041000, C606S049000
Reexamination Certificate
active
06197024
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to electrocautery surgical instruments for use in surgical procedures, and more particularly to an adjustable electrocautery surgical instrument.
BACKGROUND OF THE INVENTION
Electrocautery surgical instruments are used to make surgical cuts and to coagulate blood along surgical cuts and around surgical sites. Electrocautery surgical instruments typically have an exposed electrode blade positioned on the lower end of an elongated body. The elongated body fits comfortably in the hand of a surgeon, and allows the surgeon to control and manipulate the electrode blade much in the manner of a conventional metal scalpel. An electric cable or cord extends from the non-cutting upper end of the elongated body. One end of the electrical cord is electrically coupled to the electrode blade, while the other end of the cord is electrically coupled to a commercially available electrosurgical generator.
Electrosurgical generators have a radio frequency oscillator circuit which delivers highvoltage, high-frequency electrical signals of various waveforms to the electrode blade to selectively sever, clamp or coagulate tissue during surgical procedures. The electrosurgical generator converts wall current (110 V, 60 Hz) into high-frequency radio waves in the range of 500,000 to 1,000,00 Hz. Electrosurgical generators typically generate two or three types ofradio frequency waves. One wave is a dampened sine wave with pure coagulating properties. Another wave is a sinusoidal wave form that has pure cutting properties. Electrosurgical generators can also generate a variable sine wave with ablended current that combines characteristics of the dampened sinusoidal and sinusoidal waves. The dampened sine wave has excellent coagulating properties, but results in marked tissue destruction and charring. The sinusoidal wave cuts through tissue with little thermal damage, much like a conventional scalpel, but has no coagulation properties. Most surgical dissection is performed with a dampened sine wave output that cuts and coagulates simultaneously with minimal thermal destruction and charring. The selection of the particular type of waveform can be regulated by a foot control pedal associated with the electrosurgical generator, or by finger controls mounted on the electrosurgical instrument. See e.g. U.S. Pat. No. 5,318,565 (Kuriloff).
Most systems for supplying the current to the electrode blade utilize a dispersive, or indifferent, electrode. The dispersive electrode is typically a large metal plate which is secured to the patient and is electrically coupled to the electrosurgical generator through a cable. The electrode blade serves as an active electrode. The high frequency current produced by the electrosurgical generator radiates from the site of tissue contact of the active electrode/electrode blade, through the tissues of the patient to the larger indifferent electrode, back to the power oscillator of the electrosurgical generator, and then back again to the site of tissue contact of the electrode blade, in a continuing radiating cycle. The current reaches a high density at the site where the electrode blade contacts the tissue, producing cutting or coagulation. The dispersive electrode is relatively large in area, which keeps current density in the region of the dispersive electrode sufficiently low to avoid tissue burns in the patient, except where the electrode blade contacts tissue.
U.S. Pat. Nos. 4,919,129 (Weber) and 5,035,695 (Weber) disclose electrocautery surgical instruments having apartially retractable electrode blade. The surgical instruments include attachable extension units of varying lengths for selectively extending the operational utility of the instrument as a surgical procedure progresses. The extension units extend the electrode blade a selected dimension to facilitate deep surgical procedures in confined sites. A safety switch is included for controlling the application of high-voltage electrical signals to the electrode blade, and to thereby establish electrically inactive conditions during attachment and removal of extension units.
The present invention utilizes the above concepts, but applies them in a surgical apparatus which is adjustable in length through a wide range of motion.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the invention to provide an adjustable electrocautery surgical apparatus having an extendable and retractable electrode blade.
It is another object of the invention to provide an adjustable electrocautery surgical apparatus wherein the electrode blade can be readily extended or retracted during a surgical procedure, without delaying the surgical procedure.
It is another object of the invention to provide an adjustable electrocautery surgical apparatus wherein the electrode blade can be extended and retracted over a wide range of motion.
It is another object of the invention to provide an adjustable electrocautery surgical apparatus wherein the electrode blade can be extended and retracted over a wide range of motion without requiring removal and substitution of various length electrode blades.
These and other objects and advantages of the invention shall become apparent from the following general and preferred description of the invention.
Accordingly, an adjustable electrocautery surgical apparatus for selectively delivering electrosurgical coagulation and cut current from an electrosurgical generator to a surgical site is provided comprising an elongated body, an extension member passing at least partially through the elongated body, a track in the elongated body for guiding the extension member, an electrode blade attached to the extension member for cutting or coagulating tissue, and an adjustable lock coupled to the extension member for selectively adjusting the position of the extension member and electrode blade relative to the elongated body and for locking the extension member and electrode blade in a selected position. The elongated body member has a lower end and an upper end. A longitudinal channel passes through a sidewall of the elongated body member. A plurality of stops are positioned in the channel for providing a sequence of stop positions between maximally retracted and maximally extended positions of the apparatus. The stops may be portioned in pairs on opposite sides of the channel. The stops may also be positioned on an inner surface of the elongated body on either side of the channel. A track is disposed longitudinally in the elongated body. The track is positioned substantially parallel to the channel. An elongated extension member is slidably disposed in the track. An electrode blade extends from a lower end of the extension member, with an exposed lower end of the electrode blade extending from the lower end of the elongated body. An adjustable lock is provided on the extension member. The adjustable lock is slidably positioned in the longitudinal channel of the elongated body member so as to selectively engage the stops and thereby lock the electrode blade in a selected stop position between the maximally retracted and the maximally extended positions. The apparatus is further provided with a means for electrically coupling the electrode blade to the coagulation current of the electrosurgical generator and a means for electrically coupling the electrode blade to the cut current of the electrosurgical generator, such that coagulation or cut current, or a combination thereof, can be selectively delivered to the electrode blade.
A number of adjustable lock mechanisms are provided. In a preferred embodiment, the adjustable lock comprises an engagement member for engaging the stops, a tension member for normally biasing the engagement member in a stop position, an adjustment tab for selectively disengaging the engagement member from the stops, and a guide member disposed at least partially in the channel and fixedly coupled to the adjustment tab and the extension member, such that sliding the adjustment tab causes the extension member to slide in the track to thereby s
Dvorak Linda C. M.
Kearney R.
Sentilles Shawn D.
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