Researchers Submit Patent Application, "Electrosurgical Devices and Methods", for Approval (USPTO 20160045256)
By a News Reporter-Staff News Editor at Health & Medicine Week -- From
Washington, D.C.
, NewsRx journalists report that a patent application by the inventors Godara,
Neil (
Milton, CA
); Woo, Jason (
Mississauga
, CA); Won, Emily (
Toronto
, CA), filed on October 30, 2015, was made available online on February 25, 2016 (see also
Patents).
No assignee for this patent application has been made.
News editors obtained the following quote from the background information supplied by the inventors: "US application 20070016185 to Tullis et al is for an electrosurgical system. It discloses an electrode assembly for lesioning that includes an electrode surrounded by layers of insulation and tubing but does not disclose cooling of the lesioning electrode.
"Desinger et al (US 2004/0167517) discloses a probe having two distal region electrodes with the distal electrode tip having a cone shape that extends distally. Fluid in the lumen of the probe is spaced apart from the furthest point of the distal tip electrode.
"Fay et al (US 2009/0156981) discloses a flexible catheter having a plastic tip and a plastic shaft tube with electrodes attached to it.
"Some prior art bi-polar probes, such as those described in US application 2004/0167517 to Desinger et al and in US application 2009/0156981 to Fay et al, have configurations that allow cooling fluid to contact both the active electrode and the return electrode. As cooling fluid often has some conductivity, the flow of coolant between the electrodes will cause some energy to be transmitted within the probe rather than to surrounding tissue, resulting in a loss of effectiveness and possible safety concerns. The stray energy can also affect impedance measurements, causing further problems for devices that measure impedance."
As a supplement to the background information on this patent application, NewsRx correspondents also obtained the inventors' summary information for this patent application: "A bipolar probe used for lesioning in tissue can be cooled by including tubular electrodes configured such that the inner surface of each electrode is cooled while keeping the electrodes electrically isolated. By providing such a probe the coolant is contained in a volume that is electrically isolated from at least one of the electrodes whereby the fluid does not form a conductive link between the electrodes. The probe can include a means for temperature monitoring, which may be particularly useful when used in tissue that hinders the predictability of lesioning, such as electrically insulative tissue.
"Thus, for example, embodiments of the present invention include an electrosurgical probe comprising at least two electrically isolated conductors and a lumen for circulating a cooling fluid within only one of said at least two electrically isolated conductors, such that only one of the conductors is directly cooled by the cooling fluid. The cooling fluid circulating within the one conductor nonetheless functions to reduce the temperature of the at least two electrically isolated conductors.
"In a first broad aspect, embodiments of the present invention are for an electrosurgical probe comprising the following: at least two electrically isolated electrical conductors, including an inner electrical conductor and an outer electrical conductor. The inner electrical conductor defines a lumen for the circulation of a cooling fluid therein. An inner electrical insulator disposed between the electrical conductors electrically isolates the electrical conductors with the electrical insulator having sufficient thermal conductivity to allow for cooling of the at least two electrical conductors when the cooling fluid is circulating within the lumen of the inner electrical conductor. It is optional that the inner electrical insulator has a thickness of about 0.0254 mm (0.001'').
"Some embodiments of the first broad aspect include an outer electrical insulator disposed on the outer electrical conductor, the outer and inner electrical conductors being elongated, the inner electrical conductor being disposed coaxially within the outer conductor, and the inner conductor having a closed distal end.
"The first broad aspect also includes embodiments wherein a distal portion of the inner conductor is exposed to define a distal electrode, and a distal portion of the outer conductor is exposed to define a proximal electrode.
"Some embodiments further comprise a first temperature sensor that is proximate the distal electrode or is positioned at or adjacent to the distal electrode. The first temperature sensor can protrude from a surface of the distal electrode for enhancing isolation from the cooling fluid circulating within the inner conductor lumen. Embodiments can include a second temperature sensor, and, in some specific embodiments, the first temperature sensor is proximate the distal electrode and the second temperature sensor is proximate the proximal electrode.
"In some embodiments of the first broad aspect, when in use, the cooling fluid circulates within the inner electrical conductor lumen to contact a portion of an inner surface of the inner electrical conductor for direct cooling of the inner electrical conductor. The inner electrical insulator contacts the outer electrical conductor and the inner electrical conductor, whereby the cooling fluid circulating within the inner electrical conductor lumen indirectly cools the outer electrical conductor. In some such embodiments, a thickness of the outer electrical conductor is substantially constant along its length and a thickness of the inner electrical conductor is substantially constant along its length.
"The first broad aspect also includes some embodiments wherein a surface area of the portion of the inner electrical conductor configured to directly contact the cooling fluid is larger than a surface area of an outer surface of the distal electrode and an inner surface of the outer electrical conductor that is indirectly cooled by the cooling fluid has an area larger than an outer surface of the proximal electrode.
"Some embodiments further comprise a fluid inlet tube coupled to the inner electrical conductor lumen for supplying the cooling fluid, a fluid outlet tube coupled to the inner electrical conductor lumen to allow the cooling fluid to exit with the option that the fluid outlet tube extend along a majority of the length of the inner electrical conductor lumen. Some embodiments have a distal end of the fluid inlet tube which is proximate the proximal electrode. The fluid outlet tube can extend along a majority of the length of the inner electrical conductor lumen.
"In some embodiments of the first broad aspect, the inner electrical insulator is exposed beyond the distal edge of the proximal electrode to define an exposed inner electrical insulator. In some particular embodiments, the distal electrode, the exposed inner electrical insulator, and the proximal electrode have a length ratio of about 1:1:1 wherein it is possible that distal electrode has a length of about 10 mm, the exposed inner electrical insulator has a length of about 10 mm, and the proximal electrode has a length of about 10 mm. In other embodiments, the distal electrode, the exposed inner electrical insulator, and the proximal electrode have a length ratio of about 2:1:2, with the possibility that the distal electrode has a length of about 4 mm, the exposed inner electrical insulator has a length of about 2 mm, and the proximal electrode has a length of about 4 mm. In yet other embodiments, the distal electrode, the exposed inner electrical insulator, and the proximal electrode have a length ratio of about 7:6:7, wherein the distal electrode has a length of about 7 mm, the exposed inner electrical insulator has a length of about 6 mm, and the proximal electrode has a length of about 7 mm.
"In a second broad aspect, embodiments of the present invention are for an electrosurgical probe comprising the following: a distal electrical conductor defining a distal electrode with a closed distal end and a proximal electrical conductor defining a proximal electrode, with the distal electrode longitudinally spaced apart and electrically isolated from the proximal electrode by a distal electrical insulator. The distal electrode has a closed proximal end formed by a distal face of the distal electrical insulator to thereby define a closed distal inner lumen for circulating a cooling fluid. The proximal electrode has a closed distal end formed by a proximal face of the distal electrical insulator and a closed proximal end formed by a distal face of a proximal electrical insulator to thereby define a closed proximal inner lumen for circulating a cooling fluid.
"In some embodiments of the second broad aspect, the probe further comprises a first fluid inlet tube for supplying the distal inner lumen and a first fluid outlet tube for exit of fluid therefrom, and a second fluid inlet tube for supplying the proximal inner lumen and a second fluid outlet tube for exit of fluid therefrom.
"The second broad aspect includes some embodiments wherein the distal electrode and the proximal electrode have substantially the same diameter. In some embodiments, the distal and proximal electrical conductors are elongated.
"Some embodiments comprise a first temperature sensor located, in some specific embodiments, proximate the distal electrode or, in alternate embodiments, positioned at or adjacent to the distal electrode. The first temperature sensor can protrude from a surface of the distal electrode for enhancing isolation from the cooling fluid circulating within the distal inner lumen.
"Probes of the second aspect can further comprise a second temperature sensor, and, in some specific embodiments, the first temperature sensor is proximate the distal electrode and the second temperature sensor is proximate the proximal electrode.
"In some embodiments of the second broad aspect, when the probe is in use, the cooling fluid circulating within the distal inner lumen contacts a portion of an inner surface of the distal electrical conductor for direct cooling of the distal electrical conductor and the cooling fluid circulating within the proximal inner lumen contacts a portion of an inner surface of the proximal electrical conductor for direct cooling of the proximal electrical conductor.
"In some embodiments, a thickness of the proximal electrical conductor is substantially constant along its length, and, alternatively or in addition, a thickness of the distal electrical conductor is also substantially constant along its length.
"In some embodiments of the second broad aspect the distal and the proximal electrical conductors are electrically conductive along their lengths. Furthermore a surface area of the distal electrical conductor configured to directly contact the cooling fluid can be substantially similar to an area of an outer surface of the distal electrode. Also, a surface area of the proximal electrical conductor configured to directly contact the cooling fluid can be substantially similar to an area of an outer surface of the proximal electrode.
"In a third broad aspect, embodiments of the present invention include a system comprising the following: an electrosurgical generator, a source of cooling fluid, and at least one electrosurgical probe. An electrosurgical probe comprises the following: at least two electrically isolated electrical conductors, including an inner electrical conductor and an outer electrical conductor, the inner one of the electrical conductors defining a lumen for the circulation of a cooling fluid therein, and an inner electrical insulator disposed between the inner and outer electrical conductors for electrically isolating the electrical conductors. The inner electrical insulator has sufficient thermal conductivity to allow for cooling of the at least two electrical conductors when the cooling fluid is circulating within the lumen of the inner electrical conductor. The probe is operable to be connected to the generator for delivering energy between the inner electrical conductor and the outer electrical conductor in a bipolar manner and the lumen is operable to be connected to the source of cooling fluid for delivering fluid for cooling the inner and outer electrical conductors.
"Some embodiments of the third aspect include a distal portion of the inner electrical conductor of the probe exposed to define a distal electrode. In some embodiments, the electrosurgical probe further comprises a first temperature sensor with the first temperature sensor being located proximate the distal electrode.
"Some embodiments comprise a distal portion of the outer electrical conductor being exposed to define a proximal electrode. The at least one electrosurgical probe further comprises a second temperature sensor, with the second temperature sensor being proximate the proximal electrode.
"In some embodiments, the electrosurgical generator is operable to deliver radiofrequency energy.
"In some embodiments of the third aspect, the electrosurgical generator comprises a controller for monitoring the first temperature sensor and adjusting the energy delivered based on the sensed temperature.
"In a fourth broad aspect, embodiments of the present invention include a method of lesioning in bone tissue, the method comprising the following steps: providing a bipolar probe having an active tip comprising at least two electrodes for delivering energy, advancing the active tip into a bone tissue, delivering energy between the at least two electrodes in a bipolar manner whereby energy is delivered to tissue, and supplying cooling fluid to the active tip for internal cooling of the at least two electrodes.
"Some embodiments further comprise selecting a temperature for the cooling fluid that is supplied to the active tip wherein the temperature selected for the cooling fluid can be from just above 0 degrees C. to about 30 degrees C. Such methods can further comprise adjusting the flow rate of the cooling fluid.
"Some embodiments of the fourth broad aspect include monitoring the temperature of tissue that the energy is delivered to and, in certain embodiments, controlling the delivery of energy using the temperature of the tissue that the energy is delivered to.
"In further embodiments of the fourth aspect, the bone is a vertebral body, the energy is delivered to a nervous tissue generating pain signals at the bone-tumor interface, and/or the active tip is advanced the into a trabecular bone.
"Some methods according to the fourth aspect of the invention include an assembly comprising a cannula with a stylet disposed within. The assembly is used to advance the probe into the vertebral body, and the stylet is withdrawn from the cannula subsequent to the introducer assembly being advanced into the vertebral body.
"In some embodiments of the fourth broad aspect, the polarity of the energy delivered to the at least two electrodes is reversible.
"Some embodiments of the fourth aspect relating to the polarity of the probes being reversible include methods comprising emitting a stimulation pulse comprising a continuous train of biphasic waves at a set frequency, navigating the active tip through tissue, reversing the polarity of the at least two electrodes to identify which electrode a stimulated nerve is in proximity to, and repeating the previous steps until the location of the nerve is determined.
"Some other embodiments of the fourth aspect relating to the polarity of the probes being reversible include methods comprising the following: delivering energy to at least two electrodes for ablation, and reversing the polarity of the energy to the at least two electrodes. The method can include each probe being active for about 50 percent of the time.
"Some embodiments of the fourth aspect relating to monitoring tissue temperature include methods comprising placing at least one external temperature sensor at the boundary of a desired lesion, monitoring the at least one external temperature sensor during energy delivery, and determining the lesion is complete when the external temperature (the temperature from the sensor at the boundary) reaches a predefined value.
"Some embodiments of the fourth broad aspect include methods wherein the energy is delivered to a nerve within a vertebral body, wherein it is optional that the energy is delivered to a basivertebral nerve.
BRIEF DESCRIPTION OF THE DRAWINGS
"In order that the invention may be readily understood, embodiments of the invention are illustrated by way of examples in the accompanying drawings, in which:
"FIG. 1 is an illustration of a probe 100 in accordance with an embodiment of the present invention;
"FIG. 2a is a side view of a probe 100, showing various features in transparency for ease of illustration, in accordance with an embodiment of the present invention;
"FIG. 2b is a cross-sectional view of probe 100, taken along line 2b-2b of FIG. 2a, in accordance with an embodiment of the present invention;
"FIG. 3 is an illustration of a target location, in accordance with an embodiment of a method of the present invention;
"FIGS. 4a and 4b are illustrations of a method in accordance with an embodiment of the present invention;
"FIG. 5 is an illustration of a probe 100, in accordance with an alternate embodiment of the present invention; and
"FIGS. 6a, 6b and 6c are illustrations of a portion of a probe 100, in accordance with an embodiment of the present invention."
For additional information on this patent application, see: Godara, Neil; Woo, Jason; Won, Emily. Electrosurgical Devices and Methods. Filed October 30, 2015 and posted February 25, 2016. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5581&p=112&f=G&l=50&d=PG01&S1=20160218.PD.&OS=PD/20160218&RS=PD/20160218
Keywords for this news article include: Patents, Bone Research.
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