Surgery – Instruments – Electrical application
Reexamination Certificate
1999-09-10
2001-05-29
Cohen, Lee (Department: 3739)
Surgery
Instruments
Electrical application
C606S039000, C606S040000
Reexamination Certificate
active
06238388
ABSTRACT:
The invention is directed to an electrosurgical instrument or apparatus, and in particular to an electrosurgical instrument that operates with a lower output voltage and a lower output power.
BACKGROUND OF INVENTION
Electrosurgical instruments are well known and widely used in the medical, dental, and veterinarian fields. They offer the capability of precision cutting with electrosurgical currents in the megacycle range using a handpiece with needle, ball, or loop electrodes in a unpolar operating mode, or convenient coagulation using a forceps in a bipolar operating model. Eliman International, Inc. makes available an electrosurgical instrument, Model FFPF, which provides on its front panel connectors for receiving the plug of a unipolar handpiece and a ground or indifferent plate, as well as connectors for receiving the plugs of a bipolar forceps.
There are environments in which the electrosurgical apparatus has to satisfy stringent requirements, including but not limited to simple operation, low cost, energy efficient, safe, and user friendly. in addition, it should provide the capability of precision cutting, coagulating, and homeostasis using high radio-frequency (RF) electrical current, preferably of the order of 3.5-4 mHZ, with 4 mHZ being preferred.
We have found that most of these requirements can be satisfied with low power electrosurgical apparatus that includes only unipolar capability provided that the output power is kept low, preferably at or below about 50 watts. The Model FFPF, whose principles are described in some detail in U.S. Pat. No. 3,730,188 ('188), and further in U.S. Pat. No. 4,463,759 ('759), the contents of both of which are fully incorporated herein by reference, had an output of about 100 watts. Moreover, the Model FFPF used electron tubes, which required high voltages to operate and limited the number of user-friendly features that could be incorporated. Other commercial electrosurgical apparatus, also of the high-voltage, high-power type, employed programmable microcontrollers for producing the different current waveforms needed for surgical tissue cutting, for simultaneous cutting and coagulation, and for coagulation (hemostasis) alone, commonly referred to as the cut, cut/coag, and hemo modes, respectively. U.S. Pat. No. 3,730,188 illustrates in
FIGS. 5
a
,
5
b
and
5
c
the three modes above described. As will be noted, the cut mode current waveform is a fully-rectified, filly-filtered, continuous wave (CW) carrier at the RF frequency; the cut/coag mode current waveform is a fully-rectified, unfiltered, continuous wave (CW) carrier at the RE frequency; and the hemo mode current waveform is a half-wave rectified, unfiltered, continuous wave (CW) carrier at the RF frequency. The cut/coag and hemo mode currents are commonly referred to as modulated RF currents. The commercial electrosurgical apparatus of the high-voltage, high-power type employing microcontrollers also are more complex, require more electronic components and assembly, and are thus more expensive than the Model FFPF.
SUMMARY OF INVENTION
A principal object of the invention is an electrosurgical apparatus capable of providing optimal RF energy for the three unipolar modes described above but manufacturable at a lower cost.
Another object of the invention is an electrosurgical apparatus capable of providing optimal RF energy for the three unipolar modes described above but characterized by lower output voltage and power.
Still another object of the invention is an electrosurgical apparatus capable of providing optimal RE energy for the three unipolar modes described above but manufacturable at a lower cost yet providing many user-friendly features without the use of a microcontroller.
These objects are achieved in accordance with one aspect of the invention by an electrosurgical apparatus whose circuitry for generating the modulation signals needed to implement the three current modes employs no microcontroller but generates the modulation waveforms using a oscillator-binary counter and dual multiplexers, integrated components (ICs) that are of relatively low cost.
In accordance with another feature of the invention, safety features can be incorporated by including a timer circuit cooperating with the binary counter to provide power to the IC components and avoid overheating of the apparatus.
A feature of the invention is to use the oscillator-binary counter component to generate at plural outputs plural series of digital pulses at various frequencies, some of the pulse series being used to generate approximate sine-waves that can be employed for the cut/coag and hemo modes, and others of the pulse series being employed to operate the timer, indicator lights, and all audible warning system. Thus, many functions are performed by the circuit components thereby minimizing the component count and reducing costs.
Electrosurgical apparatus according to the invention is capable of providing high-quality RF energy at a 3.5-4 mHZ frequency best suited for delicate, precise and quick-healing cutting procedures with low leakage currents using a unipolar handpiece, as well as high-quality modulated RF energy best suited for hemostasis with the unipolar handpiece. In addition, its output RF frequency remains substantially unchanged irrespective of load changes. Moreover, it will provide a controlled duty cycle, i.e., relative times that the RF currents are delivered to a patient versus the times that delivery is interrupted, a feature that was not possible with the Model FFPF.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention, and in which like reference numerals denote the same or similar components.
REFERENCES:
patent: 4716897 (1988-01-01), Noguchi et al.
Ellman Alan G.
Garito Jon C.
Cohen Lee
Kearney R.
LandOfFree
Low-voltage electrosurgical apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low-voltage electrosurgical apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low-voltage electrosurgical apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2526309