US20170050017A1 - Electrosurgical System - Google Patents

Abstract

A system and method involving an electrode system can include a flexible shaft.

Description

TECHNICAL FIELD
• This invention relates generally to epidural field therapy.
BACKGROUND
• The use of radiofrequency (RF) generators and electrodes to be applied to tissue for pain relief or functional modification is well known. For example, the RFG-3B RF lesion generator of Radionics, Inc., Burlington, Mass. and its associated electrodes enable electrode placement of the electrode near target tissue and heating of the target tissue by RF power dissipation of the RF signal output in the target tissue. For example, the G4 generator of Cosman Medical, Inc., Burlington, Mass. and its associated electrodes such as the Cosman CSK, and cannula such as the Cosman CC and RFK cannula, enable electrode placement of the electrode near target tissue and heating of the target tissue by RF power dissipation of the RF signal output in the target tissue. Temperature monitoring of the target tissue by a temperature sensor in the electrode can control the process. Heat lesions with target tissue temperatures of 60 to 95 degrees Celsius are common. Tissue dies by heating above about 45 degrees Celsius, so this process produces the RF heat lesion. RF generator output is also applied using a pulsed RF method, whereby RF output is applied to tissue intermittently such that tissue is exposed to high electrical fields and average tissue temperature are lower, for example 42 degrees Celsius or less.
• RF generators and electrodes are used to treat pain and other diseases. Examples are the equipment and applications of Cosman Medical, Inc., Burlington, Mass. such as the G4 radiofrequency generator, the CSK electrode, CC cannula, and DGP-PM ground pad. Related information is given in the paper by Cosman E R and Cosman B J, “Methods of Making Nervous System Lesions”, in Wilkins R H, Rengachary S (eds.); Neurosurgery, New York, McGraw Hill, Vol. 3, 2490-2498; and is hereby incorporated by reference in its entirety. Related information is given in the book chapter by Cosman E R Sr and Cosman E R Jr. entitled “Radiofrequency Lesions.”, in Andres M. Lozano, Philip L. Gildenberg, and Ronald R. Tasker, eds., Textbook of Stereotactic and Functional Neurosurgery (2nd Edition), 2009, and is hereby incorporated by reference in its entirety.
• The Cosman CC cannula and RFK cannula, manufactured by Cosman Medical, Inc. in Burlington, Mass., include each an insulated cannula having a pointed metal shaft that is insulated except for an uninsulated electrode tip. The cannula has a hub at its proximal end having a luer fitting to accommodate a separate thermocouple (TC) electrode, for example the Cosman CSK electrode, Cosman TCD electrode, and Cosman TCN electrode, that can deliver electrical signal output such as RF voltage or stimulation to the uninsulated electrode tip. The Cosman CSK and TCD electrodes have a shaft that is stainless steel. The Cosman TCN electrode has a shaft that is Nitinol. A disadvantage of this system is that fluid injection into the cannula cannot be achieved when the TC electrode is also in the cannula. Another disadvantage is that the temperature sensor probe and the cannula are separate elements, which increases the complexity of the components needed for the system. Another disadvantage of the Cosman CC and RFK cannula is that its shaft is constructed from stainless steel hypotube. Another disadvantage of the Cosman CC and RFK cannula is its shaft is not flexible enough for epidural placement. Related information is given in Cosman Medical brochure “Four Electrode RF Generator”, brochure number 11682 rev A, copyright 2010, Cosman Medical, Inc., and is hereby incorporated by reference herein in its entirety.
• Each injection electrode made by Cosman Medical Inc. (Burlington, Mass.), including the CU electrode, the CR electrode, and the CP electrode models, has a shaft including metal tubing with sharp distal end for insertion into tissue to reach a spinal target. The shafts of the Cosman injection electrodes have lengths 6 cm (2.4 inches), 10 cm (3.9 inches), or 15 cm (5.9 inches). The shaft of a Cosman injection electrode is configured to penetrate the skin surface, muscle, and other tough bodily tissues to enable percutaneous placement of the electrode tip at nerves outside and around the bony spinal column. The shaft of a Cosman injection electrode is insulated except for an exposed conductive tip portion and has an electrical connection to a signal generator for delivery of stimulation or RF signal outputs to the target tissue. Each has a flexible injection tube and a port to allow injection of contrast, anaesthetic, or saline solution fluid to the target tissue. The CU electrode incorporates a temperature sensor positioned within the exposed, conductive tip portion. The CR and CP electrodes do not incorporate a temperature sensor. The CP electrode can be used to effect a stimulation-guided nerve block, whereby an electrical stimulation signal is applied to the CP electrode via its electrical connector, stimulation signals are applied to nerve tissue nearby the conductive tip of the CP electrode, and anesthetic fluid is injected through the CP shaft once desired stimulation response is achieved by positioning of the exposed tip. The CR electrode can be used to effect a stimulation-guided RF therapy without temperature control, whereby an electrical stimulation signal is applied to the CR electrode via its electrical connector, the stimulation signal is applied to nerve tissue nearby the conductive tip of the CR electrode in order to position the exposed tip of the electrode near target nerves, RF generator output is applied to the CR electrode via the same electrical connector, RF output is applied to tissue nearby the exposed tip of the electrode without temperature monitoring. The CR electrode can also be used to effect non-stimulation-guided RF therapy, whereby stimulation guidance is not utilized. The CU electrode can be used to effect a stimulation-guided RF therapy with temperature monitoring and control, whereby an electrical stimulation signal is applied to tissue via the CU electrode to position its exposed tip near target nerves, and RF output is applied to tissue near the exposed tip to effect medical treatment. The CU electrode can also be used to effect non-stimulation-guided RF therapy, whereby stimulation guidance is not utilized. The Cosman injection electrodes are not configured to be positioned by the epidural space. The shafts of the Cosman injection electrodes are not substantially flexible. The lengths of the Cosman injection electrodes' shafts are less than 5.9 inches. The Cosman injection electrodes are not structed using a spring coil. The Cosman injection electrodes are not introduced into the human body via an introducer needle, such as an epidural needle. Related information is given in Cosman Medical brochure “Four Electrode RF Generator”, brochure number 11682 rev A, copyright 2010, Cosman Medical, Inc., and is hereby incorporated by reference herein in its entirety.
• In one embodiment, U.S. Pat. No. 7,862,563 by E R Cosman Sr and E R Cosman Jr presents a unitized injection electrode with an electrically-insulated shaft, an exposed metallic tip, a temperature sensor within the exposed metallic tip, cables that connect to the electrode via a single, flexible leader connector that splits into two parts of which the first is terminated by a connector configured to carry high-frequency and stimulation signals and temperature-measurement signals, and the second is terminated by an injection port through which fluid can be injected into the shaft and out the distal end of the electrode. One limitation of this prior art is that it does not show a unitized injection electrode for which the metallic tip and insulated shaft are constructed using a spring coil and a central stiffening wire. One limitation of this prior art is that it does not show the application of a unitized injection electrode in the epidural space.
• In the prior art, the Cosman TEW electrode system includes an electrode with a spring-coil tip that has a temperature sensor at its distal closed end. The TEW electrode is introduced into the human body by means of an insulated cannula. The TEW electrode is designed for RF treatment of the trigeminal facial nerve via the foremen ovale of the human skull. The TEW electrode is not electrically insulated. The shaft of the TEW electrode is a metallic tube to the distance end of which is attached a spring coil. The coil tip of the TEW electrode is configured to emerge from the end of the cannula and into the body without diverging substantially from its predetermined curve. The TEW electrode's spring coil is no longer than 0.33 inches. The TEW electrode's spring coil emerges from the distal end of the cannula by no more than 0.33 inches. The TEW electrode is not configured to be threaded though the epidural space. The TEW electrode is not configured to be threaded through 12 inches to 34 inches of the epidural space. The TEW electrode is not long enough to apply RF therapy to multiple spinal nerves via a single skin puncture and the epidural space. The TEW electrode does not have an injection port. The TEW electrode is not configured to allow for outflow of fluids from its spring coil tip. Related information is given in Cosman Medical brochure “Four Electrode RF Generator”, brochure number 11682 rev A, copyright 2010, Cosman Medical, Inc., and is hereby incorporated by reference herein in its entirety.
• The Cosman Flextrode RF electrode system includes an electrode and an introducer cannula. The flextrode electrode's shaft is approximately 15 cm (5.9 inches) in length and is constructed from a metal tube whose distal end has a spiral cut over the distal 1.25 inches. A temperature sensor is located at the distal, closed end of the shaft. The electrode is induced into the human body via the introducer cannula which has a sharped distal end and whose shaft is electrically insulated. When the electrode is introduced through the cannula, 11 mm of the electrode extends beyond the cannulas distal end into the tissue. The Flextrode electrode is not electrically insulated. RF energy is applied to the tissue by the length of the Flextrode electrode that extends beyond the cannula's distal tip and the uninsulated distal tip of the cannula. The Flextrode is configured to penetrate tissue, such as the fibrous tissue of the intervertebral disc, where it emerges from the distal end of the cannula. The Flextrode's stiffness is configured so that its tip can move through the curved tip of the introducer cannula but remain substantially straight as it penetrates tissue. The Flextrode electrode is not configured for placement in the epidural space. The Flextrode is not configured for injection of fluids into the human body. Related information is given in Cosman Medical brochure “Four Electrode RF Generator”, brochure number 11682 rev A, copyright 2010, Cosman Medical, Inc., and is hereby incorporated by reference herein in its entirety.
• The Radionics DiscTrode RF electrode system includes an electrode and an introducer cannula. The disctrode electrode's shaft is approximately 9 inches in length and is constructed from a metal tube whose distal end has thin cuts over the distal 2.5 inches. A temperature sensor is located at the distal, closed end of the shaft. The electrode is induced into the human body via the introducer cannula which has a sharped distal end and whose shaft is electrically insulated. When the electrode is introduced through the cannula, 5 cm (2 inches) of the electrode extends beyond the cannula's distal end into the tissue. The disctrode electrode is not electrically insulated. RF energy is applied to the tissue by the length of the disctrode electrode that extends beyond the cannula's distal tip and the uninsulated distal tip of the cannula The disctrode is configured to penetrate tissue, such as the fibrous tissue of the intervertebral disc, where it emerges from the distal end of the cannula. The disctrode's stiffness is configured so that its tip can move through the curved tip of the introducer cannula but remain substantially straight as it penetrates tissue. The disctrode electrode is not configured for placement in the epidural space. The disctrode is not configured for injection of fluids into the human body. Related information is given in an article by P M Finch entitled “The Use of Radiofrequency Heat Lesions in the Treatment of Lumbar Discogenic Pain”, Pain Practice, Volume 2, Number 3, 2002, pages 235-240, which is here incorporated by reference herein in its entirety.
• The Oratec Spinecath system includes a catheter and an introducer cannula. The catheter's shaft consists of a resistive coil that is entirely covered by electrical insulation. RF energy applied to the coil heats the internal resistive coil and tissue is heated by thermal conduction. RF energy is not applied to the tissue. A temperature sensor is located in the spinecath catheter. The electrode is induced into the human body via the introducer cannula which has a sharped distal end. The spinecath emerges from the distal end of the cannula by approximately 5 cm (2 inches). The spinecath catheter is not configured for placement in the epidural space. The spinecath is not configured for injection of fluids into the human body. Related information is given in an article by P M Finch entitled “The Use of Radiofrequency Heat Lesions in the Treatment of Lumbar Discogenic Pain”, Pain Practice, Volume 2, Number 3, 2002, pages 235-240, which is here incorporated by reference herein in its entirety.
• The use of catheters in the epidural space to treat pain is well known. A flexible catheter is introduced into the epidural space through an epidural needle inserted percutaneously through the sacral hiatus, through an intervertebral foramina, or through vertebral interspaces. An injection adaptor, such as a tuohy-borst adaptor, can be attached to the proximal end of the catheter to provide for the injection of fluids into the proximal end of the catheter that outflow into patient anatomy through the distal end of the catheter. Techniques such as lysis of adhesions, chemical neurolysis of nerve roots, and other medial methods are well known. Examples of epidural catheters include the Tun-L-XL catheter manufactured by EpiMed International, Farmers Branch, Tex. The Tun-L-XL catheter comprises a stainless steel spring coil whose distal end is welded into a ball, and which is covered by a plastic tube over its entire length except for the distal end. The coil wire is closely coiled except for a region of the exposed, distal coil where the cool loops are loosely wound to provide for preferential outflow of injected fluids. The coil can have a metal safety strap welded at the proximal and distal end of the coil. A stylet comprising a metal wire and a plastic hub attached to the proximal end of the wire, is inserted into the proximal end of the catheter to stiffen it. The stylet is removed, an injection adaptor is attached to the proximal end of the catheter, and fluids can be injected. Nerve stimulation signals can be delivered through the exposed metallic tip of the catheter by connecting the proximal end of the stylet to the output of a nerve stimulator, perhaps by means of an alligator clip, while the stylet is positioned inside the catheter. Related information is in “Epidural Lysis of Adhesions and Percutaneous Neuroplasty” by Gabor B. Racz, Miles R. Day, James E. Heavner, Jeffrey P. Smith, Jared Scott, Carl E. Noe, Laslo Nagy and Hana Ilner (2012), in the book “Pain Management—Current Issues and Opinions”, Dr. Gabor Racz (Ed.), ISBN: 978-953-307-813-7, InTech, and is hereby incorporated by reference in its entirety. One disadvantage of the prior art in epidural catheters is that an electrode with a temperature monitoring is not used as a stylet. One disadvantage of the prior art in epidural catheters is that the stylet does not have an integrated connection cable to an electrical generator. One limitation of the prior art in epidural catheters is that electrical stimulation cannot be applied at the same time that fluid is injected through the catheter. One limitation of the prior art in epidural catheters is that prior catheters do not provided for temperature-controlled RF lesioning. One limitation of the prior art in epidural catheters is prior catheter systems have multiple pieces. One limitation of the prior art in epidural catheters is prior catheter systems are not a unitized injection electrode.
• U.S. Pat. No. 6,246,912 by M E Sluijter, W J Rittman, and E R Cosman presents inFIG. 9 a catheter electrode with one or more electrical contacts, where the catheter electrode is placed in the epidural space and applies high frequency signals via its electrical contacts. The electrical contact are tubular rings bonded to the substrate catheter and connected to wires internal to the catheter. The catheter may have reinforced metal spirals in its construction. The catheter electrode does not provide for the injection of fluids. The catheter electrode does not apply high frequency signals to the tissue by the same spring coil that is part of its shaft construction.
• U.S. Pat. No. 8,075,556 by A Betts presents a specific construction of a device configured for placement in the spinal canal and delivery of RF energy. Betts describes a catheter delivery device to transmit radiofrequency energy to a spinal canal, comprising: a needle having an open proximal end and an open distal end, and a lumen that extends from the open proximal end to the open distal end; a catheter having a blunt, metallic tip on a distal end of the catheter that transmits a radio frequency energy to the treatment site, wherein the catheter is telescopically disposed within the needle lumen to allow the tip to be maneuverably positioned within the spinal canal; a catheter hub coupled to a proximal end of the catheter a metallic wire element telescopically disposed within a lumen of the catheter; and an adapter hub coupled to a proximal end of the wire element, wherein the adapter hub is cooperatively engageable to the catheter hub to form a single shaft, wherein a proximal end of the adapter hub is configured couple to a radio frequency generating device, and wherein the adapter hub and the catheter hub are sized and dimensioned relative to one another such that engagement of the adapter hub to the catheter hub allows a distal end of the wire element to touch a seating surface of the tip such that the wire element delivers a radio frequency energy from the radio frequency generating device to the tip. A disadvantage of the prior art in Betts is that the catheter has an adaptor hub. A disadvantage of the system described in Betts is that a standard epidural catheter is not used. A disadvantage of the system described in Betts is that construction of the catheter using a metal coil is not described. A disadvantage of the system described in Betts is that a safety strap within the catheter shaft is not described; a disadvantage of the absence of a metallic safety strap is that the impedance of the catheter shaft can distort and/or diminish electrical signals conducted along the shaft. A disadvantage of the system described in Betts is that RF is not delivered without seating of the RF wire in the inner surface of the distal end of the catheter. A disadvantage of the system described in Betts is that the system does not provide for temperature monitoring. A disadvantage of the system described in Betts is that the system does not provide for temperature-monitored RF therapy delivered through the catheter. A disadvantage of the system described in Betts is that the RF wire does include a temperature sensor. A disadvantage of the system described in Betts is that it is not a unitized injection electrode. A disadvantage of the system described in Betts is that the RF wire is separate from the catheter. A disadvantage of the system described in Betts is that injection through the catheter cannot be effected while the RF wire is in place within the catheter. A disadvantage of the system described in Betts is that it does not provide for simultaneous injection of fluids and delivery of electrical signals.
• US patent application 2004/0210290 by Omar-Pasha describes a catheter electrode for pulsed RF treatment of nerves in the epidural space. One limitation of this prior art is that does not describe the use of a coil to construct the catheter electrode. Another limitation of this prior art is it does not describe an RF electrode system in which an RF electrode stylet is inserted into a standard epidural catheter.
• The pulsetrode electrode manufactured by BioAmpere Research SRL, Verona, Italy is a flexible electrode comprising a plastic shaft, three ring electrodes near its distal end, a hub, an injection port connected to a tube that is connected directly to the hub, a generator wire that connects directly to the hub, a moveable stylet is inserted into the injection port and travels along the shaft of the electrode. The pulsetrode is configured for placement in the epidural space and delivery of radiofrequency fields to anatomy. Related information is given in Bioampere Research brochure “Pulserode” and is hereby incorporated by reference herein in its entirety. One limitation of this prior art is that does not describe the use of a coil to construct the catheter electrode. Another limitation of this prior art is it does not describe an RF electrode system in which an RF electrode stylet is inserted into a standard epidural catheter. Another limitation of this prior art is that the distal end of the electrode is electrically insulated. Another limitation of the this prior art is that the active tip is not the sole active tip.
SUMMARY
• The present invention relates to a system and method involving an electrode system having a flexible shaft. In one aspect, the present invention relates to a system involving a radiofrequency electrode configured for placement within the epidural space. In one aspect, the present invention relates to a flexible electrode that provides for stimulation-guidance and the injection of fluids into the epidural space. In one aspect, the present invention relates to a system for performing epidural pulsed RF using stimulation guidance and guidance by means of injection of radiocontrast agents from the active tip of the electrode. In one aspect, the present invention relates to a method for construction of an epidural electrode system. In one aspect, the present invention relates to the construction of an epidural electrode using metal coil over the proximal end of which insulation is positioned. In one aspect, the present invention relates to a one-piece electrode system with flexible shaft, and injection port, and a generator connector.
• In one example, the epidural electrode system consists of a one-piece (also known as “unitized”) electrode with an injection port and generator connection, that is introduced percutaneously through an epidural needle. The electrode conducts electrical signals, such as RF and pulsed RF signals to tissue in contact with the electrode's active tip, when the electrode is energized by an electrical power supply, such as a radiofrequency generator. In a more specific example, the electrode includes a temperature sensor within is active tip to provide temperature monitoring during the delivery of electrical signal, for example to provide for temperature-controlled RF pain treatment.
• In one example, the one-piece electrode's shaft is constructed using a spring coil whose proximal end is covered by an electrically-insulated sheath, and whose distal end is closed by a weld that incorporates the spring coil, any internal RF wires, any internal thermocouple wires, and internal structuring wires, such as a safety strap or fixed stylet. One advantage of this example is ease of manufacturing.
• In one example, the one-piece electrode's shaft is constructed using a spring coil whose proximal end is covered by an electrically-insulated sheath; whose distal end is closed by a weld that incorporates the spring coil, any internal RF wires, any internal thermocouple wires, and internal structuring wires, such as a safety strap; and into whose proximal end a separate moveable stylet is inserted. One advantage of this example is ease of manufacturing.
• In one example, the epidural electrode system consists of a two-piece system including a catheter with metallic tip and a RF electrode configured to be placed within the inner lumen of the catheter. One advantage of this example, this that the RF electrode can both deliver RF to the catheter tip, monitor the temperature at the catheter tip, and provide variable stiffening of the catheter shaft and tip.
• One advantage of using a coil to construct the shaft and tip of a unitized injection electrode is that the shaft is flexible. One advantage of flexible shaft and tip in unitized injection electrode is that the electrode can be placed in the epidural space of the human body. One advantage of an epidural unitized injection electrode system is that injection of fluids and delivery of electrical signals, such as RF, can be effected at the same time. Ease of manufacturing is one advantage of the method of constructing a unitized injection electrode system for epidural RF using a spring coil covered with an insulative sheath and terminated at this distal end by a weld joint that captures internal RF and thermocouple wires.
• Ease of manufacturing is one advantage of an epidural catheter electrode system for which an RF electrode is used as a stylet for an epidural catheter.
DESCRIPTION OF DRAWINGS
• FIG. 1A is a schematic diagram showing a system including a catheter electrode wherein the electrode is placed in the epidural space and energized in a monopolar manner where a ground pad carries return currents from the electrode.
• FIG. 1B is a schematic diagram showing a system including two catheter electrodes wherein the electrodes are placed in the epidural space and energized in a bipolar manner where current passes between electrodes.
• FIG. 2A is a schematic diagram showing in an external view a unitized injection electrode with a flexible active tip, a flexible shaft, an injection port, and a generator connector.
• FIG. 2B is a schematic diagram showing in an external view a unitized injection electrode with a flexible active tip, a flexible shaft depicted in a straight position, an injection port, and a generator connector.
• FIG. 2C is a schematic diagram showing in a sectional view a unitized injection electrode where a coil is used in the construction of the shaft and active tip, and where the electrode has a an integrated stylet, temperature sensor, injection port, and a generator connector.
• FIG. 2D is a schematic diagram showing in a sectional view a unitized injection electrode where a coil is used in the construction of the shaft and active tip, and where the electrode has a an integrated stylet, temperature sensor, injection port, and a generator connector.
• FIG. 2E is a schematic diagram showing in a sectional view a unitized injection electrode where a coil is used in the construction of the shaft and active tip, and where the electrode has a an integrated safety strap, temperature sensor, injection port, and a generator connector.
• FIG. 3 is a schematic diagram showing a unitized injection electrode with a flexible active tip, closed distal end with diameter larger than the outer diameter of the proximal part of the active tip, a flexible shaft, an injection port, and a generator connector in an external view.
• FIG. 4A is a schematic diagram showing connector in an external view a unitized injection electrode with a flexible active tip, a flexible shaft depicted in a straight position, an injection port, a generator connector, and a moveable stylet.
• FIG. 4B is a schematic diagram showing in a sectional view a moveable stylet positioned inside a unitized injection electrode where a coil is used in the construction of the shaft and active tip, where the electrode has a temperature sensor, injection port, and a generator connector.
• FIG. 5A is a schematic diagram showing connector in an external view a unitized injection electrode system with a flexible active tip, a flexible shaft depicted in a straight position, an injection port, a generator connector, and a moveable stylet, where the injection port and generator connector are each connected separately by means of a dedicated tube to the proximal end of the electrode.
• FIG. 5B is a schematic diagram showing in a sectional view a moveable stylet positioned inside a unitized injection electrode where a coil is used in the construction of the shaft and active tip, where the electrode has a temperature sensor, injection port, and a generator connector, and where the injection port and generator connector are each connected separately by means of a dedicated tube to the proximal end of the electrode.
• FIG. 6A is a schematic diagram showing connector in an external view a unitized injection electrode system with a flexible active tip, a flexible shaft, an injection port, a generator connector, and a moveable stylet, where the injection port is integrated into the hub at the proximal end of the electrode.
• FIG. 6B is a schematic diagram showing in a sectional view a moveable stylet positioned inside a unitized injection electrode where a coil is used in the construction of the shaft and active tip, where the electrode has a temperature sensor, injection port, and a generator connector, and where the injection port is integrated into the hub at the proximal end of the electrode.
• FIG. 7 is a schematic diagram showing connector in an external view a unitized injection electrode system with a flexible active tip, a flexible shaft, an injection port, a generator connector, and a moveable stylet, where the injection port and generator connector are both integrated into the hub at the proximal end of the electrode.
• FIG. 8A is a schematic diagram showing in an external view an electrode system comprising a flexible catheter and stylet electrode.
• FIG. 8B is a schematic diagram showing in a sectional view an electrode system comprising a flexible catheter and stylet electrode.
• FIG. 9A is a schematic diagram showing in an external view an electrode system comprising a flexible catheter and stylet electrode.
• FIG. 9B is a schematic diagram showing in a sectional view an electrode system comprising a flexible catheter and stylet electrode.
• Like reference symbols in the various drawings indicate like elements.
• A reference to a figure by its numeric index alone is a reference to all figures having that numeric index as their prefex; for example, “FIG. 4” refers toFIG. 4A andFIG. 4B collectively.
DETAILED DESCRIPTION
• FIG. 1A presents an electrode system comprisinginjection electrode160, introducer needle170,ground pad184, andgenerator180, in accordance with one aspect of the present invention.Syringe159 can be attached toport150 ofelectrode160 to provide for the injection of fluids intobody190 throughelectrode160. In one embodiment, the system can provide for stimulation-guided epidural anesthesia and temperature-monitored radiofrequency treatment, include pulsed radiofrequency treatment, of nerves. In one embodiment, the system can provide for the application of high frequency electric fields to nerve by means of placing an electrode via the epidural space. In one embodiment, the system can provide for the application of high-frequency electric fields to nerve by means of placing an electrode via the neural foramina. In one embodiment, the system can provide for cost-effective manufacturing of a catheter electrode configured for placement in the epidural space. In one embodiment, the system can provide for cost-effective manufacturing of a temperature-monitoring catheter electrode configured for placement in the epidural space. In one embodiment, the system can provide for the construction of a catheter electrode capable of delivery of nerve stimulation signals, delivery of radiofrequency signals, and fluid injection for medical procedures, such as pain management. In one embodiment, nerve stimulation signals produced bygenerator180 can be used to position theelectrode160 for the purpose of an epidural anesthesia procedure, such as lysis of adhesions, chemical epidural neurolysis, epidural injection of alcohol, and epidural injection of phenol. In one embodiment, theelectrode160 can provide for the injection of fluids, such as radiocontrast agents, anesthetics, neurolytics agents, alcohol, phenol, saline, hyaluronidase, local anesthetic, corticosteroids, hypertonic saline. In one embodiment, theelectrode tip100 andshaft110 can be visible in x-ray images, such as fluoroscopy. An advantage of this embodiment is that radiographic imaging can be used to position theelectrode160 in thehuman body190. In one example, the system can be used to relieve pain. In one example, the system can be used to relieve pain by means of pulsed RF application to a dorsal root ganglion. In one example, the system can be used to relieve pain. In one example, the system can be used to relieve pain by means of pulsed RF application to spinal nerve. In one example, the system can be used to relieve pain due to cancer. In one example, the system can be used to relieve pain due to cancer by means of radiofrequency heat lesioning of a dorsal nerve root. One advantage of the application of radiofrequency using an epidurally placed electrode is that nerve structures at multiple levels of the spine can be targeted by moving the epidural electrode through the epidural space.
• Electrode160 comprisesactive tip100,shaft110, proximal end of theshaft111,hub120,cable131,injection port150,generator cable133, andgenerator connector140. Introducer needle170 compriseshub171 andshaft172.Generator180 is connected toleader cable181 andconnector182 to provide for connection toelectrode connector160.Generator180 is connected toleader cable183 andground pad184.Ground pad184 is placed on the skin surface ofhuman body190.Human body190 hasbrain191,spinal cord192, andspinal nerves193.Electrode160 is positioned in thehuman body190.Electrode160 enters thehuman body190 by passing through needle170.Generator180 can generate an electrical potential between theground pad184 and theelectrode160, and thereby electrical current flows from theactive tip100 of theelectrode160, through thebody190, to thereference ground pad184. In one example,electrode160 is positioned in the epidural space in thehuman body190. In one example,electrode160 enters the epidural space via a median or paramedian approach. In one example,electrode160 enters the epidural space via the sacral hiatus. In one example,electrode160 enters the epidural space via an intervertebral foramina of the spinal column. In one example, theactive tip100 of theelectrode160 is positioned near a dorsal spinal nerve root. In one example, theactive tip100 of theelectrode160 is positioned near a dorsal root ganglion (DRG). In one example, theactive tip100 of theelectrode160 is positioned near a spinal nerve.
• In one embodiment, thegenerator180 is a medical radiofrequency generator. In one embodiment, thegenerator180 provides for temperature-controlled radiofrequency and pulsed radiofrequency treatment of chronic pain. In one embodiment, thegenerator180 is a high frequency electrical generator. In one embodiment, thegenerator180 is nerve stimulator. In one embodiment, thegenerator180 includes a temperature-measurement circuit.
• In one embodiment, the needle170 is an epidural needle. In one embodiment, the needle170 is a tuohy needle. In one embodiment, the needle170 has sigmoidal tip geometry, as shown inFIG. 1A. In one embodiment, the needle170 is a spinal needle.
• Theelectrode160 can have one of a number of constructions in accordance with the present invention. In one embodiment,electrode160 has one of the constructions shown inFIG. 2. In one embodiment,electrode160 has one of the constructions shown inFIG. 3. In one embodiment,electrode160 has one of the constructions shown inFIG. 4. In one embodiment,electrode160 has one of the constructions shown inFIG. 5. In one embodiment,electrode160 has one of the constructions shown inFIG. 6. In one embodiment,electrode160 has one of the constructions shown inFIG. 7. In one embodiment,electrode160 has one of the constructions shown inFIG. 8, whereincable131 is omitted. In one embodiment,electrode160 has one of the constructions shown inFIG. 8, whereincable131 is omitted andport150 is omitted. Theelectrode160 can be a unitized injection electrode. Theelectrode160 can be a catheter into which a physically-separate electrode is inserted. Theelectrode160 can be constructed using a spring coil. Theelectrode160 can include a temperature sensor, such as a thermocouple.
• Theelectrode160 can be configured for placement in the epidural space of ahuman body190. The electrode can have aflexible shaft110 andtip100. Thetip100 can be an uninsulated metallic coil, such as a round-wire spring coil, a flat-wire spring coil, a spiral cut metal tube, a laser-cut metal tube. Thetip100 can be stainless steel. Theshaft110 andtip100 can include the same coil. Theshaft110 can be electrically insulated.
• FIG. 1A shows one embodiment of cables for aninjection electrode160, wherein aroot cable131 provides a flow path for fluids injected intoport150 and housing for wires fromgenerator connector140,port140 provides an opening for injection of fluids, andgenerator cable133 carries wires fromgenerator connector150. In one embodiment, fluids injection intoport150 flow through theshaft110 of the electrode and outflow into thebody190 through thetip100. In one embodiment,port150 is a luer port.
• In one embodiment,needle hub171 is a port, such as a luer port, through which fluids can be injected. In one embodiment, theneedle shaft172 is partially electrically-insulated with an metallic active tip and can be used as an RF cannula. In one embodiment, the needle170 is an RF cannula.
• FIG. 1B presents an electrode system comprising afirst injection electrode60, asecond injection electrode65, afirst introducer needle70, asecond introducer needle75, andgenerator180, in accordance with one aspect of the present invention.Syringe59 can be attached to port50 ofelectrode60 to provide for the injection of fluids intobody90 throughelectrode60.
• Syringe59 can be attached to port55 ofelectrode65 to provide for the injection of fluids intobody90 throughelectrode65.Electrode60 is introduced into thehuman body90 throughneedle70.Electrode65 is introduced into thehuman body90 throughneedle75. In oneembodiment electrode60 can be equivalent toelectrode160 inFIG. 1A. In oneembodiment electrode65 can be equivalent toelectrode160 inFIG. 1A. In one example,Electrodes60 and65 can both be placed in the epidural space of the same human body at the same time, andelectrodes60 and65 can be connected to opposite poles of thegenerator180, and thereby be energized in a bipolar manner. An advantage of this configuration is that bipolar RF therapy can be effected in the epidural space of thehuman body190.
• Referring toFIG. 2, meaningFIGS. 2A, 2B, 2C, 2D, and 2E, in accordance with one aspect of the present invention, a unitized injection electrode is presented that comprises anactive tip200, an electricallyinsulated shaft210, ahub220,cables230,electrical signal connector240, andinjection port250. The electrode can be constructed so that itsactive tip200,insulated shaft210,hub220,cables230,signal connector240, andinjection port250 are inseparably connected. The distal end of the electrode is the end of theactive tip200, and the proximal end of the electrode is end of thecables230. Electrode structures that are more distal are closer to thedistal tip205. Electrode structures that are more proximal are closer to thegenerator connector240 and/or to theinjection port250.
• Theactive tip200 is constructed fromcoil201 and closeddistal end205. The closeddistal end205 can be a weld, which can be formed by laser, electrical discharge, or other methods known to one skilled in the art. The closed205 distal end can be formed with conductive glue. The closeddistal end205 can be created using solder. The close distal end can be formed using glue. The closeddistal end205 can be configured to be electrically conductive. The closeddistal end205 can be configured to be electrically connected to thecoil201. Thetip200 can be configured to deliver electrical signals, such as stimulation and RF signals, to tissue, such as nerves. Thetip200 can be configured to allow for the outflow of fluid. Thetip200 can be configured to allow for preferential outflow of fluid from one or more parts of the tip. In the embodiment presented inFIG. 2, thetip200 has aproximal region202 which is closely-coiled wire. Thetip200 has amiddle region203 in which the coils are separated to allow for fluid outflow. For example, theoutflow region203 can have a ratio between wire diameter and inter-wire spacing of 1:1. Thetip200 has adistal region204 which is closely-coiled wire. It is understood one or more of thetip regions202,203, and204 can be omitted in other embodiments of the electrode.
• The closeddistal end205 can have the same outer diameter as the outer diameter of the rest of theactive tip200. The closeddistal end205 can be full radiused. The closeddistal end205 can be hemispherical. The closeddistal end205 can be flat. The closeddistal end205 can have a smaller diameter than the outer diameter of the rest of theactive tip200. The closeddistal end205 can have a larger diameter than the outer diameter of the rest of theactive tip200. In another embodiment of the present invention, thedistal end205 can be open; an advantage of this embodiment is that fluid can exit the electrode from the distal end.
• Theinsulated shaft210 is constructed ofelectrical insulation211 that surrounds thecoil201 within it. Thecoil201 within the shaft can be closely coiled wire like that of theproximal tip region202. In one embodiment, thecoil201 can extend through the entire length of theshaft210. In one embodiment, thecoil201 can extend only part of the length of theinsulated shaft210 and connect to another structure that has different flexibility, such as a tube or a spiral-cut tube. In one embodiment, thecoil201 can extend though theshaft210 and thehub220. In one embodiment, thecoil201 can extend though theshaft210, thehub220, and thecables230.
• Thetip200 andshaft210 can be flexible. Thetip200 andshaft210 can be configured for placement within the epidural space in the human body. Thecoil201 can be a stainless steel spring coil. In one example, thecoil201 can be a spring coil used in the construction of epidural catheters, as is familiar to one skilled in the art of epidural anesthesia. Thecoil201 can be constructed of wound round wire. Thecoil201 can be constructed of wound flat wire. Thecoil201 can be laser-cut tubing. Thecoil201 can be laser-cut stainless-steel hypodermic tubing. Theelectrical insulation211 can be constructed from one or more pieces and/or applications of medical grade plastic tubing, fluoropolymers, fluoroelastomers, silicone, polyester, polyolefin, polyimide, and other materials that are familiar to one skilled in the art of RF electrodes and epidural catheters. Theelectrical insulation211 can be constructed from materials configured to produce shaft stiffness appropriate for epidural placement in the human body. Theelectrical insulation211 can be a single a tube of fluoropolymer material, such as PTFE, FEP, ETFE, PET. Theelectrical insulation211 can be heat shrink tubing that is shrunk over thecoil201. Theelectrical insulation211 can be applied by coating the wire of thecoil201 before that wire is wound into thecoil201. Theelectrical insulation211 can be PTFE heat shrink tubing that is shrunk over thecoil201. Theelectrical insulation211 can be FEP heat shrink tubing that is shrunk over thecoil201. Theelectrical insulation211 can be ETFE heat shrink tubing that is shrunk over thecoil201. Theelectrical insulation211 can be PET heat shrink tubing that is shrunk over thecoil201. Theelectrical insulation211 can consist of two layers of plastic material that surround thespring coil201, as is familiar to one skilled in the art of epidural anesthesia catheters. Theelectrical insulation211 can be produced by applying a layer of a first material to the coil, for example by spraying or painting, and then applying a second material, such as a tube, over the first material. Thecoil201 can be wound wire of 0.004 inch diameter. Thecoil201 can be wound wire of 0.005 inch diameter. Thecoil201 can be wound wire of 0.006 inch diameter. Thecoil201 can be wound wire of 0.007 inch diameter. Thecoil201 can be wound wire of less than 0.004 inch diameter. Thecoil201 can be wound wire of greater than 0.007 inch diameter. The outer diameter of thecoil201 can be in therange 21 gauge to 18 gauge. The outer diameter of thecoil201 can be smaller than 21 gauge. The outer diameter of thecoil201 can be larger than 18 gauge. The outer diameter of thecoil201 can be 20 gauge. The outer diameter of thecoil201 can be 19 gauge. Theelectrical insulation211 can have wall thickness in the range 0.003 inches to 0.008 inches. Theelectrical insulation211 can have wall thickness less than 0.003 inches. Theelectrical insulation211 can have wall thickness greater than 0.008 inches. Theelectrical insulation211 can have wall thickness 0.005 inches. The outflow section of thecoil203 can have spaces between adjacent coil loops that is substantially equal to the thickness of the wire from which the coil is wound. The outflow section of thecoil203 can have spaces between adjacent coil loops that is in the range 0.003 inches to 0.008 inches. The outflow section of thecoil203 can have spaces between adjacent coil loops that is less than 0.003 inches. The outflow section of thecoil203 can have spaces between adjacent coil loops that is greater than 0.008 inches. The outflow section of thecoil203 can have spaces between adjacent coil loops that is 0.005 inches. The outflow section of thecoil203 can have spaces between adjacent coil loops that is 0.006 inches. The length of the outflow section of the coil can be in the range 0.100 to 0.140 inches. The length of the outflow section of the coil can be less than 0.100. The length of the outflow section of the coil can be greater than 0.140 inches. The length of the outflow section of the coil can be 0.120 inches.
• In another embodiment of the electrode, more than one segment of insulation can be applied along the length of the electrode shaft, withbare coil201 between each segment; an advantage of this embodiment is that RF energy can be applied to multiple separated tissue regions without applying RF energy directly to intervening regions. In another embodiment, a segment of insulation can coverclosed end205 and thedistal end204 of thetip200. In another embodiment of the electrode, the insulation can be configured such that at one or more segments of the shaft, there is a gap in the insulation on one side of the shaft that exposes theunderlying coil201, and insulation covers the other opposite side of the coil; an advantage of this embodiment is that RF energy can be applied to tissue in contact with only one side of the electrode.
• Thetip200 can have length between 2 mm and 60 mm. Thetip200 can be longer than 60 mm. The length of theactive tip200 can be 5 mm. The length of theactive tip200 can be 10 mm. The length of theactive tip200 can be 15 mm. The length of theactive tip200 can be 20 mm. The length of theactive tip200 can be 25 mm. The length of theactive tip200 can be 30 mm. Theactive tip200 can have length configured to the application of RF signals to nerves for pain management. Theactive tip200 can have length configured for epidural placement and injection of epidural anesthetics.
• The length of theshaft210 can be between 12 inches and 33 inches. The length of theshaft210 can be configured for epidural anesthesia procedures, as if familiar one skilled in the art. The length of theshaft210 can be longer than 33 inches. The length of theshaft210 can be shorter than 12 inches. The length of theshaft210 can be 16 inches. The length of theshaft210 can be configured to reach the L2 vertebral level percutaneously and epidurally via the sacral hiatus.
• Thehub220 can have a diameter larger than theinsulated shaft210. Thehub220 can be configured to facilitate rotation of theelectrode shaft210 andtip200. Thehub220 can be omitted and thecables230 can connect directly to theshaft210. Thehub220 can have similar outer dimension and aspect as tuohy-borst adaptors that are typically attached to the end of epidural catheters, as is familiar one skilled in the art. Thehub220 can have outer diameter in the range 0.250 inches to 0.500 inches. Thehub220 can have outer diameter less than 0.250 inches. Thehub220 can have outer diameter greater than 0.500 inches.
• Thecable230 can be flexible. Thecable230 can be rigid. Thecable230 can have both rigid and flexible element. Thecable230 can have a hollow inner lumen capable of carrying injected fluids into theelectrode shaft210 andtip200. Thecable230 can contain a tube capable of carrying wires for connection to the jacks on an RF generator. In one embodiment, thecables230 can be construction from flexible tubes, glue, and wires for connection to the generator. In one embodiment, thecables230 can be construction from flexible tubes, glue, a Y-splitter structure, and wires for connection to the generator. In one embodiment, thecable230 can be constructed like the cable of the Cosman CU electrode, sold by Cosman Medical, Inc. In other embodiments, the cable can be constructed using the systems and methods presented in U.S. Pat. No. 7,862,563 by E R Cosman Sr and E R Cosman Jr. In the embodiment shown inFIG. 2, thecable230 has asingle root231 that connects to thehub220, abranch232 that connects to and carries fluid frominjection port250, and abranch233 that connects to and carries wires from theconnector240.
• Theelectrical signal connector240 can be configured to carry signals from an RF generator to theactive tip200 of the electrode, as is familiar to one skilled in the art. In one embodiment, theconnector240 can be configured to connect to a nerve stimulation device Theconnector240 can be configured to carry sensory nerve stimulation signals, motor nerve stimulation signals, thermal RF signals, pulsed RF signals, signals with carrier frequency in the radiofrequency range, signals withcarrier frequency 500 kHz, signals with one component in the radiofrequency range, signals with one component in the range 250-1000 kHz. Theconnector240 can be configured to carry temperature measurement signal(s) from the electrode to an RF generator or another temperature measurement device, as if familiar to one skilled in the art. In the embodiment presented inFIG. 2, thegenerator plug240 comprises twopins242 and243, of which one can both connect to one output pole of an RF generator and to one pole of the RF generator's temperature sensing circuit, and of which the other can connect to the second pole of the RF generator's temperature sensing circuit. For example, pin242 can connect to one lead from a thermocouple or thermistor sensor in theactive tip200 of the electrode, and pin243 can connect to the other lead from the said thermocouple or thermistor sensor in theactive tip200 of the electrode. Theconnector240 can be configured to carry other signals, such as additional temperature measurement signals, as is familiar to one skilled in the art. In one embodiment, theconnector240 can have more than two pins. In one embodiment, theconnector240 can have three pins. In one embodiment, theconnector240 can have at least three pins, of which one carries therapeutic and/or diagnostic signals from a generator to the electrode, and the other two connect to a thermocouple contained in the electrode.
• Theinjection port250 can be configured to carry injected fluids into and through thecables230, thehub220, theshaft210, and out thetip200. Theinjection port250 can be configured to aspirate fluids from theelectrode tip200, for example to confirm proper placement of theelectrode tip200, as is familiar one skilled in the art of epidural anesthesia. The injection port can be a female luer injection port. Theport250 can have a luer lock. Theport250 can have a cap. Thecable232 connecting the luer injection port can have an external clamp to prevent outflow of fluids.
• FIG. 2A presents one embodiment of the present invention in which theshaft210 andtip200 are positioned in one example of a flexed position.
• FIG. 2B presents the electrode shown inFIG. 2A, where itsflexible tip200 andflexible shaft210 are in substantially straight position.
• FIG. 2C,FIG. 2D, andFIG. 2E presents three embodiments of the internal construction of the electrode fromFIGS. 2A and 2B, shown in cross-sectional views. Referring now toFIG. 2C,FIG. 2D, andFIG. 2E, thecoil201 is shown in a cross-sectional view wherein round-wire winds appear substantially elliptical. In another embodiment ofcoil201, the cross-section of thecoil201 does not appear as an ellipse, for example if flat wire is used to construct thecoil201, the cross section has a substantially rectangular. In one example, thecoil201 is a stainless steel spring coil, which is familiar to one skilled in the art of epidural catheters. The closeddistal end205 of thetip200 is shown in cross-section. Theinsulation211 is shown in a cross-sectional view wherein its tubular structure appears on both sides of thecoil201. In one example, theinsulation211 is a flexible plastic tube, familiar to one skilled in the art of epidural catheters. In one example, theinsulation211 is constructed from a flexible plastic tube within which is another coating, as is familiar to one skilled in the art of epidural catheters. Thehub220 is shown in cross-section wherein its tubular structure appears on both sides of theinsulation211 and thetubing234. In one example, thehub220 is a rigid structure composed of a plastic tube and glue that prevents fluid leakage out from thecoil201,insulation211, andinjection tube234.
• Theinjection tube234 is shown in a cross-sectional view wherein its tubular structure appears on opposite sides of the central lumen of theinjection branch232 and theroot231 of thecable230. Theinjection tube234 connects theinjection port250 and thehub220. Theinjection tube234 provides a channel through which fluids injected into theinjection port250 can flow into theshaft210, into thetip200, and then out from spaces between the coil loops of thetip200, preferentially through the larger gaps between coil loops in theoutflow section203 of thetip200. Theinjection port250 is shown in a cross-sectional view wherein it appears on opposite sides of the opening at the end of theinjection port branch232 of thecable230. Theport250 can be a female luer connector. Theconnector branch233 of thecable230 is shown in cross-sectional view so that its walls appear on opposite sides of the internal space through whichwires236 and237 travel from thegenerator connector240 into theroot231 of thecable230. Theconnector240 is shown in a cross-sectional view wherein pins242 and243 and mounted within thebody241, which appears in three parts around and between thepins242 and243. It is understood that thewires236 and237 can each be constructed from multiple pieces of wire, rod, tubing, solder joints, crimps, hooks, and other elements familiar to one skilled in the art of medial device manufacturing.
• Thewall235 of theinjection tube234 limits fluid flow into theconnector branch233 of thecable230. It is understood that thiswall portion235 can, in another embodiment, be constructed of a different material from that of thetube234; for example, from a glue plug. Thewires236 and237 travel through thewall235. It is understood that other embodiments of the construction of thecables230 can be used to provide both connection to a generator and a pathway for injection of fluids. For example, the cable constructions presented in U.S. Pat. No. 7,862,563 by E R Cosman Sr and E R Cosman Jr can be used. For example, thecable230 can be constructed like the cable of the Cosman CU electrode, sold by Cosman Medical, Inc.
• Thewire236 can be configured to carry electrical signal output from an RF generator and/or a stimulation waveform generator. Thewire236 can be composed of a conductive material, such as copper. Thewire236 can be coated with an electrical insulator. Thewire236 can be bare. Thewire236 can be configured to connect viapin242 to both the electrical signal output of a generator, such as an RF generator, and to the first terminal of a temperature-monitoring circuit, which can be integrated into the same generator or which can be housed in a separate unit. Thewire237 can be configured to connect viapin243 to the second terminal of the said temperature monitoring circuit. Thewire237 can be an electrically-insulated constantan wire. In another embodiment,pin242 connects to the electrical signal output of a generator,wire236 carries signals from the output of said generator,pin243 has isolated prongs each of which connects to a isolated terminal of a temperature-monitoring circuit, andwire237 is an bifilar thermocouple wire, such as a copper-constantan bifilar.
• Referring now specifically toFIG. 2C, the unitized injection electrode includes acentral wire260 within the inner lumen of thecoil201. Thecentral wire260 can be configured to stiffen theshaft210 and thetip200 of the electrode. Thecentral wire260 can be configured to provide sufficient stiffness for epidural placement of the electrode, and limited stiffness to prevent puncture of sensitive structures around the epidural space, as is familiar to one skilled in the art of epidural catheters. Thecentral wire260 can be a stainless steel rod. Thecentral wire260 can be copper. Thecentral wire260 can be a tapered metal rod. Thecentral wire260 can be a rod with a substantially circular cross section. Thecentral wire260 can be a hollow tube. Thecentral wire260 can be a plastic rod. Thecentral wire260 can be a rod with a substantially rectangular cross section. Thecentral wire260 can be electrically conductive. Thecentral wire260 can be electrically insulative. Therod260 can be a bare metal structure. Therod260 can be covered by an electrically-insulative coating. Thecentral wire260 can have an outer dimension in the range 0.001″ to 0.016″. Thecentral wire260 can have an outer diameter 0.010″. The central wire can have an outer diameter 0.011″. Thecentral wire260 can have an outer diameter 0.012″. The central wire can have an outer diameter 0.013″. Thecentral wire260 can have an outer diameter 0.014″. The central wire can have an outer diameter greater than 0.016″. Thecentral wire260 can have an outer diameter configured to fit within thecoil201 and to allow injected fluid to flow from one end of the coil to the other. Thecentral wire260 can be configured to conduct electrical signals, such as high frequency signals, RF output, and nerve stimulation signals, from a generator to thetip200 of the electrode. Thecentral wire260 can be configured to reduce the impedance of electrical potentials, such as high frequency electrical waveforms, radiofrequency potentials, and nerve stimulation waveforms, between thegenerator connector240 and the uninsulatedmetallic electrode tip200. The dimensions of thecentral wire260 can be configured to provide a flow path of desired area for injected fluids along the electrode shaft.
• Thecentral wire260 can be attached at the distal end of thecoil201 and at the proximal end of thecoil201; one advantage of this embodiment of the invention is that thecentral wire260 prevents extension of thecoil201 if itsdistal end204 or theclosed end205 is caught in some anatomy, such as between two vertebra. Thecentral wire260 can carry electrical signals from the generator to thetip200 of thecoil201; one advantage of this of this embodiment of the invention is that it reduces the electrical impedance between the generator and theactive tip200 of the electrode. Thecentral wire260 can be configured to maintain a bent configuration. Thecentral wire260 can be configured to maintain a bent configuration when bent by the user, such as a physician. An advantage ofcentral wire260 holding a bend is that a bend can be imposed in the electrode shaft. An advantage of a bent electrode shaft is that the bend can maneuvering of the electrode in the human body, such as in the epidural space.
• Thecentral wire260 is connected atjunction263 to both the proximal end of thecoil201 and to thewire236. Thejunction263 can be electrically conductive. Thejunction263 can create an electrically connection between thewire263 and thecoil201. Thejunction263 can create an electrical connection between thewire263 and thecentral rod260. Thejunction263 can be configured to transmit electrical signals from thewire263 to thecoil201, either by direct electrical connection of thewire263 to thecoil201, by electrical connection between thewire263 androd260 and then electrical connection between therod260 and thecoil201 atjunction261, or both. In one example, thejunction263 is a solder joint. In another example, thejunction263 includes both a weld and a solder joint. In another example, thejunction263 includes glue. In another example, thejunction263 includes a mechanical lock. In another example thejunction263 is a weld, such as a laser weld. In one example, thejunction263 is a solder joint that incorporates thecoil201, thewire236, and thecentral wire260. In another example, thejunction263 is a solder joint between thewire236 and thecentral wire260, and thecentral wire260 is configured so that it mechanically locks with thecoil201; for instance, thecentral wire260 can be folded over on itself so that it hooks around the proximal end of thecoil201. In another example, the junction can be a laser weld between thecentral wire260 and thecoil201, and a solder joint between thewire236 and thecoil201. It is understood that thejunction263 can take other forms as is familiar to one skilled in the art of medical device manufacturing. In another embodiment, thecentral wire260 can be anchored to another element of thehub220.
• Thecentral wire260 is connected to the closeddistal end205 of thetip200 atjunction261. Thejunction261 can be electrically conductive. Thejunction261 can be electrically insulative. Thejunction261 can be configured so that therod260 and the closeddistal end205 connected electrically. In one example, thejunction261 is part of the weld that formed the closeddistal end205. It is understood that thejunction263 can take other forms as is familiar to one skilled in the art of medical device manufacturing, including without limitation, gluing, welding, soldering, crimping, hooking, mechanical locking.
• Thewire237 is connected to the closeddistal end205 of thetip200 atjunction262. Thejunction262 can be electrically conductive. Thejunction262 can be electrically insulative. Thejunction262 can be configured so that therod260 and the closeddistal end205 connected electrically. In one example, thejunction262 is part of the weld that formed the closeddistal end205. It is understood that thejunction263 can take other forms as is familiar to one skilled in the art of medical device manufacturing, including without limitation, gluing, welding, soldering, crimping, hooking, mechanical locking. In one embodiment thewire237 is an insulated constantan wire, thecoil201 is stainless steel, and thejunction262 is electrically conductive such that it forms a thermocouple junction. In one embodiment thewire237 is an insulated metal wire, thecoil201 is composed of a dissimilar metal, and thejunction262 is electrically conductive such that it forms a thermocouple junction. In one embodiment, the closeddistal end205 is a weld that incorporates both thewire237 and thecoil201. In one embodiment, the closeddistal end205 is a solder joint that incorporates both thewire237 and thecoil201. In one embodiment, thewire237 is a thermocouple bifilar, such as a copper-constantan bifilar, as is familiar to one skilled in the art of thermocouples, and the junction includes an element that forms the thermocouple junction between the two wires of the bifilar237, for example by means of a weld, and an element that mechanically attaches the distal end of thebifilar wire237 to the closed end of thecoil205.
• It is understood in different embodiments that thewire237 can take any one of a number of paths along theshaft210, for example, entirely within the coil inner lumen, between thecoil201 andinsulation210, or passing into the inner lumen and out into the space between theinsulation211 and thecoil201 by passing between adjacent loops of thecoil201 any number of times.
• In one example, the closed end of the coil is a weld that connects thewire237, therod260, and thecoil201. In one example, the closed end of the coil is a solder joint that connects thewire237, therod260, and thecoil201.
• In one example, thewire236, thecentral wire260 and thecoil201 itself carry electrical output of an electrosurgical generator, such as radiofrequency and/or stimulation waveforms, to thetip200 of the electrode. In one example,wires236 and237 connect to opposite poles of a temperature sensor, such as a thermocouple junction, at thetip200 of the electrode, and conduct signals from said temperature sensor to a temperature monitoring system.
• In another embodiment, thetemperature connection243, thewire237, and thejunction262 can be omitted. In this embodiment, electrical signals are conducted through the electrode without temperature monitoring. An advantage of this embodiment is that it is easier to build. An advantage of this embodiment is that the electrode provides for stimulation-guided placement in the epidural space. An advantage of this embodiment is that it can be used for non-temperature-monitored application of RF therapy, such as thermal RF lesioning and pulsed RF treatment.
• In one embodiment of the present invention, an example of which is shown inFIG. 2C, the unitized electrode is configured for placement in the epidural space, temperature monitoring of the electrode's active tip, and delivery of radiofrequency signals via the electrode's active tip; wherein the electrode consists of a metallic coil with a proximal and distal end, an electrically insulative sheath that covers the proximal length of the coil and leaves the distal end of the coil exposed, a temperature sensor in exposed distal end of the coil, a port that allows for injection of fluids into the inner lumen of the coil, and a connector to an electrosurgical generator. In a more specific embodiment, the unitized electrode includes a central wire that mechanically connects the distal end of the coil to proximal hub structures. In a more specific embodiment, the said spring coil is stainless steel. In a more specific embodiment, a thermocouple junction is formed at the distal tip of the electrode by welding a constantan wire to the coil and to the central metallic wire.
• Referring now toFIG. 2D, the unitized injection electrode includes acentral wire270. In this embodiment,junction273 connects thecentral wire270 and thewire236, andjunction271 connects thecentral wire270 to the closeddistal end205 of theactive tip200.Junction272 is the connection of thewire237 to the closeddistal end205 of theactive tip200. In one embodiment, high frequency electrical signals are carried to theactive tip200 of the electrode viawire236 androd270. In one embodiment, the junction betweenwires237 and270 at the closeddistal end205 form a thermocouple junction. In one embodiment, thewire236 is a bifilar wire that carries signals from a temperature sensor atjunction272. Thejunction273 andwire236 can be configured to anchor therod270 to the generator connector; an advantage of this configuration is that thewire270 prevents thetip200 from separating from the electrode. Thejunction273 can include elements familiar to one skilled in the art of medical device construction, including soldering, welding, crimping, clamping, gluing, hooking, and twisting. In one example, therod270 is cover by electrically insulation along its length, so that signals carried bywire236 are not conveyed to the closeddistal end205 by thecoil201. In another example, therod270 is uninsulated so that electrical signals are carried to theactive tip200 via thecoil201 if the coil touches thecentral wire270. Thecentral wire270 can be a metal rod. Thecentral wire270 can be a flat wire with rectangular cross section. Thecentral wire270 can have outer diameter at a value in the range 0.001 to 0.018 inches. Thecentral wire270 can have outer diameter 0.011 inches. Thecentral wire270 can have a rectangular cross section with cross section substantially similar to 0.003 inches by 0.009 inches. Thecentral wire270 can be dimension and geometry configured to provide desired separation force between thetip200 and thehub220. Thecentral wire270 can be dimension and geometry configured to provide desired separation force between the distal end of thecoil201 and the proximal end of thecoil201. Thecentral wire270 can be configured to produce a desired flexibility for theshaft210 andtip200. Thecentral wire270 can be configured to maintain a bent configuration. Thecentral wire270 can be configured to maintain a bent configuration when bent by the user, such as a physician. An advantage ofcentral wire270 holding a bend is that a bend can be imposed in the electrode shaft. An advantage of a bent electrode shaft is that the bend can maneuvering of the electrode in the human body, such as in the epidural space. Thecentral wire270 can be configured so that the electrode is suitable for placement in the epidural space.
• Referring now toFIG. 2E, the unitized injection electrode includes asafety strap280. Thesafety strap280 is connected to the distal end of thecoil201 atjunction281 and to the proximal end of thecoil201 atjunction283. Thewire236 is connected to thecoil201 atjunction283. Thewire237 is connected to the distal end of thecoil201 atjunction282. Thewire236 and thecoil201 itself can carry RF output and/or stimulation output to theactive tip200 of the electrode from a medical electrosurgical generator to whichconnector240 is attached. In one embodiment, the junction between thespring coil201 and thewire237 at the closeddistal end205 of thecoil201 forms a temperature sensor, such as a thermocouple, and thewires236 and237 carry signals from said temperature sensor to theconnector240. In another embodiment, thewire237 is a bifilar wire, such as a copper-constantan thermocouple wire, andjunction272 is a temperature-sensing junction, such as a thermocouple weld, that is mechanically anchored to thetip200. Thesafety strap280 can be a metal rod. Thesafety strap280 can be a flat wire with rectangular cross section. Thesafety strap280 can have outer diameter at a value in the range 0.001 to 0.018 inches. Thesafety strap280 can have outer diameter 0.010 inches. Thesafety strap280 can have a rectangular cross section with cross section substantially similar to 0.003 inches by 0.009 inches. Thesafety strap280 can be dimension and geometry configured to provide desired separation force between thetip200 and thehub220. Thesafety strap280 can be dimension and geometry configured to provide desired separation force between the distal end of thecoil201 and the proximal end of thecoil201. Thesafety strap280 can be configured to produce a desired flexibility for theshaft210 andtip200. Thesafety strap280 can be configured to maintain a bent configuration. Thesafety strap280 can be configured to maintain a bent configuration when bent by the user, such as a physician. An advantage ofsafety strap280 holding a bend is that a bend can be imposed in the electrode shaft. An advantage of a bent electrode shaft is that the bend can maneuvering of the electrode in the human body, such as in the epidural space. Thesafety strap280 can be configured so that the electrode is suitable for placement in the epidural space.
• FIG. 3 presents a unitized injection electrode for which the closeddistal end305 has a larger outer diameter than the outer diameter of the rest of theactive tip300, in accordance with one aspect of the present invention. In one embodiment, the electrode inFIG. 3 is analogous to the electrode presented inFIG. 2. The electrode comprises a flexibleactive tip300, an electrically-insulatedflexible shaft310, ahub320,cables330,electrical signal connector340, andinjection port350. The electrode can be constructed so that itsactive tip300,insulated shaft310,hub320,cables330,signal connector340, andinjection port350 are inseparably connected. The distal end of the electrode is the end of theactive tip300, and the proximal end of the electrode is end of thecables230. As in the electrode presented inFIG. 2A, in one embodiment, thetip300 andshaft310 include acoil301, andelectrical insulation311 covers the coil in theshaft region310 and is absent in thetip region300, to form the metallicactive tip300 of the electrode. The tip includes anoutflow region303 that can be configured to preferentially emit fluids injected into theport350. Theactive tip300 can be configured to be energized by a generator attached toconnector340. Temperature can be measured at theactive tip300 by a temperature measurement circuit attached to theconnector340. The length of the electrode'sshaft310 can be configured for epidural placement. The length of the electrode's activemetallic tip300 can be in the range 2-30 mm or more, and it can be configured by performing RF and pulsed RF therapy.
• FIGS. 4A and 4B each present a unitized injection electrode withmovable stylet460, in accordance with one aspect of the present invention. The electrode withstylet460 can be configured for placement in the epidural space. Referring to bothFIG. 4A andFIG. 4B, thestylet460 comprises ahub461 andshaft462. The electrode, within which thesytlet460 can move, comprises anactive tip400, an electricallyinsulated shaft410, ahub420,cables430,electrical signal connector440, andinjection port450. The electrode can be constructed so that itsactive tip400,insulated shaft410,hub420,cables430,signal connector440, andinjection port450 are inseparably connected. InFIGS. 4A and 4B, thesylet460 is shown positioned within the unitized injection electrode. Thetip400 can be constructed from ametallic coil401, such as stainless steel spring coil, and have regions oftight coiling402 and404, and regions oflooser coiling403 to allow for preferential outflow of fluids injection intoport450, and a closeddistal end405 that is, in one embodiment, blunt and atraumatic. Thecoil401 can extend into theshaft region410, where it is covered byelectrical insulation411. Theactive tip400 can be configured to be energized by a generator attached toconnector440. Temperature can be measured at theactive tip400 by a temperature measurement circuit attached to theconnector440. Thestylet hub461 can be configured to be grasped by human fingers. Thestylet hub461 can be omitted. Theelectrode hub420 can be omitted. The length of the electrode'sshaft410 can be configured for epidural placement. The length of the electrode'sshaft410 can be in the range 12 to 33 inches. The length of the electrode's activemetallic tip400 can be in the range 2-30 mm or more, and it can be configured by performing RF and pulsed RF therapy. The diameter of theelectrode shaft410 andtip400 can be in therange 21 gauge to 18 gauge.Electrode shaft410 andtip400 can be substantially equal to 19 gauge.Electrode shaft410 andtip400 can be substantially equal to 20 gauge.Electrode shaft410 andtip400 can configured for epidural placement.
• The distal end of the electrode is the end of theactive tip400, and the proximal end of the electrode is end of thecables430. Electrode structures that are more distal are closer to thedistal tip405. Electrode structures that are more proximal are closer to thegenerator connector440 and/or to theinjection port450. The distal end of thestylet460 is thedistal tip463. The proximal end of thestylet460 is thehandle461.
• When inserted, thestylet460 can enter theport450, travel throughbranch432 and431 of thecables430, thehub420,shaft410, and all, part, or none of thetip400. In one embodiment, not shown, thecable branches431 and432 can present a straight path through which the stylet moves. In one embodiment, thecable branches431 and432 can be rigid in whole or in part to facilitate movement of thestylet shaft462 within them. In one embodiment thecable branch433 that is associated with thegenerator connector440 is flexible. In another embodiment thecable branch433 that is associated with thegenerator connector440 is rigid.
• Theshaft410 andtip400 can both be flexible when thestylet460 is inserted and when thestylet460 is not inserted. The stylet can be physically separable460 from the electrode. An advantage of the embodiment where thestylet460 can be fully withdrawn and removed from the electrode is that when the stylet is fully removed from the electrode, fluids can be injected intoport450 and delivered to anatomy nearby theelectrode tip400. Thestylet460 can be physically inseparable from the electrode, for example, by providing a mechanical element that prevents removal of the stylet from the electrode. The electrode andstylet460 can be configured to enable the user to move thestylet460 within the inner lumen of the electrode; an advantage of a unitized injection electrode with amoveable stylet460, is that thestylet460 can be moved to adjust the flexibility of theelectrode tip400 andshaft410. The electrode andstylet460 can be configured for placement in the epidural space of the human body. The electrode can be configured to provide for radiofrequency treatment and injection of fluids, such as radiocontrast agents, anesthetics, neurolytics agents, alcohol, phenol, saline, hyaluronidase, local anesthetic, corticosteroids, hypertonic saline. The electrode can be configured to monitor the temperature at thetip400 of the electrode. The electrode andstylet460 can be configured for stimulation-guided epidural anesthesia, such as lysis of adhesions. The electrode can be configured to be radiopaque. Thestylet shaft462 can be configured to be radiopaque. An advantage of the electrode being radiovisible is that x-ray guidance, such a fluoroscopy, can be used to position the electrode in the human body. An advantage of thestylet460 being radiovisible is that x-ray guidance, such a fluoroscopy, can be used to position the electrode in the human body. The construction of thestylet460 can be that of epidural catheters. Thestylet shaft462 can be a stainless steel rode. Thestylet shaft462 can have outer diameter that is a value in the range 0.001 inches to 0.018 inches. Thestylet shaft462 can have outer diameter greater than 0.018 inches. Thestylet shaft462 can have outer diameter that is 0.010 inches. Thestylet shaft462 can be configured to be flexible enough to move through thecables430,shaft410, andtip400. Thestylet shaft462 can be configured to maintain a bent configuration. An advantage of thesytlet460 holding a bend is that a bend can be imposed in the electrode shaft when thestylet460 is in place. An advantage of a bent electrode shaft is that the bend can maneuvering of the electrode in the human body, such as in the epidural space.
• Referring now toFIG. 4A, an external view of a unitized injection electrode andstylet460 is shown.
• Referring now toFIG. 4B, a cross-section of the unitized injection electrode is presented and shows one embodiment of its construction. Theshaft462 of thestylet460 is within the inner lumen of thecoil401, which appears as a series of substantially circular elements in the cross-sectional view. The tip of thestylet463 can touch the inner surface of the electrode'sdistal end405 when the stylet is fully inserted. The tip of thestylet463 can be configured so that is cannot touch the inner surface of the electrode'sdistal end405 when the stylet is fully inserted. One advantage of the distal tip of the stylet's463 not being able to touch the inner surface of the electrode's distal end when fully inserted is that it ensures the distal end of thecoil401, for instance theregion404, is less stiff than the rest of thetip400 andshaft410 at all times.
• Pin442 ofconnector440 can be configured to connect to the electrical output of a medical electrical generator, such as an RF generator or a nerve stimulator.Pin442 is connected to wire436.Wire436 is connector to thecoil401 and thesafety strap480 atjunction484.Safety strap480 is connected to thecoil401 at itsdistal end405 atjunction481.Pin442,wire236,coil401,strap480 can be configured to carry electrical signals, such as RF generator output, to theactive tip400 of the electrode from a medical generator connected to pin442. In another example, thesafety strap480 can be electrically insulative. Thewire436 can include a conductive metal, such as copper. Thesafety strap480 can include a conductive metal, such as stainless steel. Thesafety strap480 can be a stainless steel flat wire. The cross-section of the safety strap can be substantially rectangular with dimension substantially similar to 0.005 inches by 0.010 inches. One advantage of thesafety strap480 being a flat wire is that thesafety strap480 has a low profile. One advantage of thesafety strap480 being a flat wire is that thesafety strap480 obstructs less of the fluid flow path within the lumen of thecoil401. One advantage of thesafety strap480 being a flat wire is that a largerdiameter stylet shaft462 can passed into the inner lumen of thecoil401. Thesafety strap480 can be configured to help prevent thecoil401 from changing length and/or uncoiling within the body. In another embodiment, thesafety strap480 can be omitted, in whichcase junction484 is betweenwire436 andcoil401, and thecoil401 itself carries electrical signals to itsactive tip400.
• In oneembodiment pin443 connects to one pole of temperature-monitoring circuit and pin442 connects to the other pole of said temperature-monitoring circuit. In this embodiment,wire437 connects to pin443 and is electrically-insulated constantan wire, and thesafety strap480 andcoil401 can both be stainless steel. The distal end of thecoil405 can be a weld that connects thecoil401, thestrap480, and theconstantan wire237 to form a thermocouple junction from which the said temperature-monitoring circuit measures temperatures. In another embodiment,pin443 has two electrically-isolated prongs that connect to both poles of a temperature-monitoring circuit, thewire437 is a bifilar of dissimilar metals, such as copper-constantan thermocouple wire, thejunction482 is the thermocouple formed by connection of the two wires of the bifilar437 to form a thermocouple, and the temperature-monitoring circuit measures temperature from thethermocouple482; thethermocouple482 can be connected to thecoil401 within the length of the tip or to its closeddistal end405.
• It is understood, that thewire437 can be positioned outside the coil for all or part of the length of thehub420 andshaft411. It is understood, that thewire437 can pass into and out of thecoil401 along its length by passing between adjacent loops of thecoil401. One advantage of thewire437 being outside the inner lumen of thecoil401 is that it is like likely to be damaged by themovable stylet shaft462.
• FIG. 5 presents a unitized injection electrode with moveable stylet in accordance one aspect with the present invention.FIG. 5A shows an external view of the unitized injection electrode.FIG. 5B shows one embodiment of the internal construction of the unitized injection electrode in a cross-section view. In one embodiment, the embodiments presented inFIG. 5A andFIG. 5B are analogous to the embodiments presented inFIG. 4A andFIG. 4B, with the difference that inFIG. 5, the injection cable branch, labeled532 inFIG. 5 and labeled432 inFIG. 4, and the generator cable branch, labeled533 inFIG. 5 and labeled433 inFIG. 4, are connected directly to the hub, labeled520 inFIG. 5 labeled420 inFIG. 4, whereas inFIG. 4 the injection cable branch and generator cable branch connect to aroot cable branch431 that connects to thehub420. In one embodiment, the injection electrode with moveable stylet is configured for RF therapy. In one embodiment, the injection electrode with moveable stylet is configured to be placed in the epidural space. In one embodiment, the injection electrode withmoveable stylet560 is configured for injection of fluid through thetip500. In one embodiment, thestylet560 can be removed from the electrode to allow for delivery of fluids from thetip500 by means of injection intoport550. In one example, theelectrode shaft510 andtip500 are flexible. In one embodiment, the injection electrode is configured to measure the temperature of tissue in contact with theactive tip500 of the electrode. In one embodiment, the injection electrode is configured to effect temperature-controlled radiofrequency treatment, including pulsed radiofrequency therapy, of nerves by means of placement of the electrode in the epidural space of a human patient in order to manage said patient's pain. In one embodiment, the unitized injection electrode with moveable stylet is configured to apply radiofrequency electric fields, including pulsed radiofrequency electric fields, to spinal nerves, spinal nerve roots, dorsal spinal nerve roots, and/or dorsal root ganglia, by placement of the electrode in the epidural space and/or the spinal foramina.
• The distal end of the electrode is the end of theactive tip500, and the proximal end of the electrode is end of the cables530. Electrode structures that are more distal are closer to thedistal tip505. Electrode structures that are more proximal are closer to thegenerator connector540 and/or to theinjection port550. The distal end of thestylet560 is thedistal tip563. The proximal end of thestylet560 is thehandle561.
• The unitized injection electrode hastip500 comprising ametallic coil501 withdistal end505,shaft510 comprisingelectrical insulation511 covering themetallic coil501,hub520,generator cable533,connector540 comprisingbody541 and pins542 and543,injection cable532,injection port550, andmovable stylet560 comprisinghub561 andshaft562. In one embodiment,elements500,510,520,533,540,532, and550 are inseparably connected. In oneembodiment injection tube532 is straight. In oneembodiment injection tube532 is curved. In oneembodiment injection tube532 is flexible. In oneembodiment injection tube532 is rigid. In oneembodiment generator cable533 is flexible. In oneembodiment generator cable533 is rigid. In one embodiment, thestylet shaft562 is a metal rod. In one embodiment, thestylet shaft562 is a strainless steel rod. In one embodiment, thestylet shaft562 is a nitinol rod. One advantage of amoveable stylet560 is that the flexibility of theelectrode shaft510 andtip500 can be adjusted by movement of thestylet560.
• In another embodiment, theinjection tubing532 can be omitted and theinjection port550 directly connected to thehub520. In another embodiment, thegenerator cable533 can be omitted and theconnector540 directly connected to thehub520. In another embodiment, thehub520 can be omitted, and theinjection cable532 and thegenerator cable533 directly connected to theelectrode shaft510. In another embodiment, thehub520 can be omitted, theinjection tube532 omitted, theinjection port550 directly connected to theelectrode shaft510, and thegenerator cable533 directly connected to theelectrode shaft510. In another embodiment, thehub520 can be omitted, theelectrode cable532 omitted, theinjection tube532 directly connected to theelectrode shaft510, and thegenerator connector540 directly connected to theelectrode shaft510. In another embodiment, thehub520 can be omitted, theelectrode cable532 omitted, theinjection tube532 omitted, theinjection port550 directly connected to theelectrode shaft510, and thegenerator connector540 directly connected to theelectrode shaft510. In another embodiment, theinjection tube532 and theinjection port550 can be omitted, thestylet560 can be inserted directly into the inner lumen of thecoil501, and a separate injection port, such as a tuohy-borst adaptor, can be connected to the shaft when thestylet560 is withdrawn from electrode to provide for injection of fluid through the electrode into tissue in which the electrode tip is placed.
• Referring now toFIG. 5A specifically, an external view of the electrode is shown with thestylet560 in place within the electrode.
• Referring now toFIG. 5B specifically, a cross-sectional view of one embodiment of the internal construction of the electrode is shown with thestylet560 in place within the inner lumen of the electrode. In one embodiment, thestylet shaft562 is configured so that when it fully inserted into the electrode, thedistal tip563 of thestylet shaft562 contacts the inner surface of thedistal tip505 of the electrode. In another embodiment, thestylet shaft562 is configured so that when it fully inserted into the electrode, thedistal tip563 of thestylet shaft562 is does not contact the inner surface of thedistal tip505 of the electrode.Element535 is configured to limit or prevent the flow of fluid into thegenerator cable533.Wire536 and537 pass throughelement535. In one embodiment,element535 includes the wall of theinjection tube532. In one embodiment,element535 includes glue, such as a glue plug. In one embodiment,element535 includes the wall of theshaft insulation511. In one embodiment,wire537 can passes into the inner lumen of thecoil501 via its proximal end, as illustrated inFIG. 5B. In another embodiment,wire537 can enter the inner lumen ofcoil501 by passing between links of thecoil501.Pin542 is electrically connected to wire536, which is electrically connected tocoil501 atjunction583, which can be, for example, a weld or solder joint. In one embodiment, electrical output from a generator connected to pin542 is conducted to theactive tip500 of the electrode viawire536,junction583, andcoil501.Pin543 is electrically connected to wire537, which is connected to thedistal end505 of the electrode atjunction582. In one embodiment,distal end505 is a weld that incorporates thewire537. In one embodiment,distal end505 is a solder joint that incorporates thewire537. In one embodiment,distal end505 is a glue joint that connects to thewire537. In one embodiment,wire537 is a constantan wire, thecoil501 is stainless steel, the connection between thecoil501 and thewire537 is a thermocouple junction,pin542 is configured to be attached to a temperature-measurement circuit,pin542 is configured to be attached to the same temperature-measurement circuit, and thereby the temperature of tissue in contact with thedistal tip505 of the electrode. In another embodiment,wire537 comprises insulated constantan and copper wires whosejunction582 is a thermocouple junction,pin543 comprises two electrically-isolated pins of which each is connected tone of the twowires comprising wire537, said two electrically-isolated pins are configured to be connected to a temperature-measurement system, and thereby the temperature of tissue in contact with theelectrode tip500 can be measured. Thesafety strap580 can connect to the distal and proximal end of thecoil501 atjunctions581 and584, respectively. One advantage of thesafety strap580 is that it makes theshaft510 and tip500 more robust. In one embodiment, thesafety strap580 can be metallic, such as a stainless steel flat wire. One advantage of ametallic safety strap580 is that it reduces the electrical impedance between the proximal and distal ends of thecoil501. One advantage of ametallic safety strap580 is that electrical signals are conducted with less distortion fromwire536 to theactive tip500 of the electrode. In another embodiment, thesafety strap580 can be omitted. In another embodiment, thewire537 can include elements, such as a wire, that is configured to serve as a safety strap.
• FIG. 6 presents a unitized injection electrode with moveable stylet, in accordance with one aspect of the present invention.FIG. 6A shows an external view of the unitized injection electrode.FIG. 6B shows one embodiment of the internal construction of the unitized injection electrode in a cross-section view, with the exterior of thestylet660 shown. In one embodiment, the embodiments presented inFIG. 6A andFIG. 6B are equivalent to the embodiments presented inFIG. 5A andFIG. 5B, with the difference that the injection cable branch labeled532 inFIG. 5 is omitted inFIG. 6, and the injection port, labeled550 inFIG. 5 and labeled650 inFIG. 6, is directly connected to thehub620 inFIG. 6. One advantage of the direct connection of theinjection port650 to thehub620 the pathway for fluid injection can be reduced.
• The unitized injection electrode hastip600 comprising ametallic coil601 withdistal end605,shaft610 comprisingelectrical insulation611 covering themetallic coil601,hub620,generator cable633,connector640 comprisingbody641 and pins642 and643,injection port650, andmovable stylet660 comprisinghub661 andshaft662. In one embodiment,elements600,610,620,633,640, and650 are inseparably connected. Thetip600 can have aregion603 for which the coil loops are more loosely spaced than in other regions, such asregion601 and602.
• The distal end of the electrode is the end of theactive tip600, and the proximal end of the electrode is end of the cables630. Electrode structures that are more distal are closer to thedistal tip605. Electrode structures that are more proximal are closer to thegenerator connector640 and/or to theinjection port650. The distal end of thestylet660 is thedistal tip663. The proximal end of thestylet660 is thehandle661.
• Referring now toFIG. 6B specifically, the electrode haswire636,wire637, andsafety strap680.Wire637 can be a constantan wire that connects to pin643, and that connects to thedistal end605 of thecoil601 atjunction682 to form a thermocouple junction.Wire637 can be a thermocoupe bifilar terminated by athermocouple junction682 that connects to twopins composing pin643.Pin643 is configured to provide for monitoring of the tip temperature by connection to a temperature-measurement device.Wire637 connects to pin642 and tocoil601 to provide for conduction of electrical signals from a electrosurgical generator attached to pin642 to theactive tip600 of the electrode. In embodiments where a thermocouple junction is formed between aconstantan wire637 and thedistal end605 or thecoil601, thepin642 can connect to a temperature-measuring device to provide for monitoring of the temperature of tissue in contact with theactive tip600.
• Wire637 can enter thelumen coil601 by passing between two loops ofcoil601. In another embodiment, thewire637 can enter the lumen of thecoil601 be passing into the proximal end of thecoil601. In another embodiment, thewire637 can enter the inner lumen of thecoil601 at a more distal point along the shaft than pictured inFIG. 6B; an advantage of this embodiment is that thestylet shaft662 and thewire637 can touch each other over a shorter length. It is understood that a structure can be added to the end of thegenerator cable633 where it connects to thehub620 that is configured to limit flow of fluids into thegenerator cable633, such as a glue plug.
• FIG. 7 presents a unitized injection electrode with moveable stylet in an external view. In one embodiment, the embodiments presented inFIG. 7 are equivalent to the embodiments presented inFIG. 6A andFIG. 6B, with the difference that the generator cable branch labeled633 inFIG. 6 is omitted inFIG. 7, and the injection port, labeled650 inFIG. 6 and labeled750 inFIG. 7, is directly connected to thehub720 inFIG. 7. The unitized injection electrode hastip700 comprising ametallic coil701 withdistal end705,shaft710 comprisingelectrical insulation711 covering themetallic coil701,hub720,connector740 comprisingbody741 and pins742 and743,injection port750, andmovable stylet760 comprisinghub761 andshaft762. In one embodiment,elements700,710,720,740, and750 are inseparably connected. Thetip700 can have aregion703 for which the coil loops are more loosely spaced than in other regions, such asregion701 and702.
• FIG. 8 present an injection electrode system comprising acatheter890 and separate,movable stylet electrode860, in accordance with one aspect of the present invention.FIG. 8A presents one embodiment of the injection electrode system in an external view.FIG. 8B presents one embodiment of the internal construction of the injection electrode system, wherein thecatheter890 is shown in a cross-sectional view and theelectrode860 is shown from its exterior, positioned within thecatheter890. Referring to bothFIG. 8A andFIG. 8B, thecatheter890 comprises atip comprising coil801 anddistal end805,shaft810 comprisinginsulation811 outside thecoil801,hub820, andinjection port850. Theelectrode860 comprisesshaft862,hub860,cable830,generator connector840 comprisingbody841 and pins842 and843. The distal end of the catheter is the end of thedistal point805, and the proximal end of the electrode is end of thehub820. Catheter structures that are more distal are closer to thedistal tip805. Catheter structures that are more proximal are closer to theport850. The distal end of thestylet electorde860 is thedistal tip863. The proximal end of thestylet electrode860 is thehandle861.
• In one embodiment, when theelectrode860 is positions within the inner lumen of thecatheter890 and electrical signals are delivered to theelectrode shaft862 by connecting the electrode to an electrical signal generator viaconnector840, contact between theelectrode shaft862 and the inner surfaces of themetallic coil801, said electrical signals are conducted to theactive tip800 of thecatheter890 and thereby delivered to tissue in contact with theactive tip800. In one embodiment, the injection electrode system inFIG. 8 can be used in the embodiments presented inFIG. 1A andFIG. 1B. The injection electrode system can provide for radiofrequency therapy by means ofcatheter890 placement in the spinal canal. The injection electrode system can provide epidural anesthesia. The injection electrode system can provide stimulation-guided RF and pulsed RF treatment of nervous structures, such as the DRG, via placement of thecatheter890 within the spinal canal. The injection electrode system can provide for stimulation-guided epidural anesthesia, such a lysis of adhesions. The injection electrode system can provide for temperature-monitoring of thecatheter tip800 during medical use.
• Theport850 can be integrated inseparably into thehub820. In one embodiment, thehub820 andinjection port850 can be inseparably connected to theshaft810. In another embodiment, aunitized hub820 andinjection port850 can be separable from the shaft; for example. Theunitized hub820 andinjection port850 can take the form of a tuohy-borst adaptor or another common type of injection adaptor that is familiar to one skilled in the art of epidural anesthesia. The electrode can be moveable within the catheter. The electrode can be fully removed from the catheter. The electrode can be fully removed from the catheter to provide access to theinjection port850 for the injection of fluid through the catheter and outflowing from thecatheter tip800, for example, for the purpose of effective epidural anesthesia.
• In some embodiments, theshaft810 and tip800 of thecatheter890 can have the same construction to the shaft and tip of electrodes presented inFIGS. 2, 3, 4, 5, 6, and 7. In one embodiment, thecoil801 can be a stainless steel spring coil of round wire. In one embodiment, thecoil801 can be a stainless steel spring coil of flat wire. In one embodiment, thecoil801 can be a laser cut stainless steel tube. It is understood that in other embodiments, thecoil801 is not present over the entire length of theshaft810; for example, the proximal end of thecoil801 can be connected to metal tubing, such as stainless steel hypotube, to provide for a stiffer proximal part of the shaft. It is understood that multiple pieces of coil can be connected to form thecoil801. In some embodiments, the catheter electrode system presented inFIG. 8A andFIG. 8B has the same construction and function as the injection electrode system presented inFIG. 9A andFIG. 9B.
• Theelectrode890 can have constructions that are familiar to one skilled in the art of RF pain management. For example,electrode890 can have a construction similar to that of the Cosman CSK electrode. For example,electrode890 can have a construction similar to that of the Cosman TCD electrode. For example,electrode890 can have a construction similar to that of the Cosman TCN electrode, whose shaft includes nitinol. Theelectrode890 can be a temperature-sensing electrode. Theelectrode890 can have a thermocouple temperature sensor at its distal863. Theelectrode860 can be configured to provide for the delivery of radiofrequency current to thecatheter890. Theconnector840 can be configured to connect to a radiofrequency generator.
• Referring toFIG. 8A andFIG. 8B, thecatheter890 can be an epidural catheter. Thecatheter890 can be an intravascular catheter. Thecatheter890 can be configured for epidural anesthesia. Thestylet electrode860 can be configured act as a stylet for thecatheter890. Thestylet electrode860 can be configured to deliver electrical signals to theactive tip800 of thecatheter890. Thestylet electrode860 can be configured to deliver RF signals to theactive tip800 of thecatheter890. Thestylet electrode860 can be configured to deliver nerve stimulation signals to theactive tip800 of thecatheter890. The injection electrode system presented inFIG. 8 can be configured to effect radiofrequency treatment, such as pulsed radiofrequency treatment, on nerve structures by means of placement of the electrode system in the epidural space of a human body. One advantage of the injection electrode system presented inFIG. 8 is that manufacture of theelectrode860 and thecatheter890 can proceed in parallel. Another advantage of the injection electrode system presented inFIG. 8 is that standard epidural methods can be used in addition to RF methods in the same medical procedure. Another advantage of the injection electrode system presented inFIG. 8 wherein the unitizedhub820 andinjection port850 is separable fromshaft810 of thecatheter890, is that the needle used to introduce thecatheter890 can be removed from the patient while thecatheter890 is in place within the patient, by sliding said needle over the distal end of theshaft810, as is familiar one skilled in the art of epidural anesthesia.
• Referring now specifically toFIG. 8B, in one embodiment of the injection electrode system, thecatheter890 has asafety strap880 connected to the proximal end of thecoil801 atjunction884 and to the distal end of thecoil801 atjunction881. Thejunction884 can be a weld, such as a laser weld. Thejunction881 can be part of the weld, such as a laser weld or an electrical discharge weld, that forms theclosed end805 of thecatheter890. Thesafety strap880 can be configured to prevent thecoil801 from uncoiling during use. The safety strap can be a metal wire. The safety strap can be a flat wire. The safety strap can be configured to have a low profile to allow entry of the stylet electrode'sshaft862 into the inner lumen of thecoil801. The safety strap can be configured to have a low profile to maintain an open cross-sectional area within the inner lumen of the coil for the flow of injected and aspirated fluid. In embodiments where thesafety strap880 is a metal wire, the safety strap can improve faithful conduction of electrical signals delivered by theelectrode860 to theactive tip800 of thecatheter890.
• Referring toFIG. 8A andFIG. 8B, the length of thecatheter890 can be in the range 12-33 inches. The length of thecatheter890 can be less than 12 inches. The length of thecatheter890 can be greater than 33 inches. The length of thecatheter890 can be 12 inches. The length of thecatheter890 can 33 inches. The length of thecatheter890 can be 16 inches. The length of thecatheter890 can be 24 inches. The outer diameter of thecatheter890 can in the range 18 to 21 gauge. The outer diameter of thecatheter890 can be greater than 18 gauge. The outer diameter of thecatheter890 can be less than 21 gauge. The outer diameter of thecatheter890 can be 20 gauge. The outer diameter of thecatheter890 can be 19 gauge. The diameter of theelectrode860 can be configured to produce a desired stiffness of the assembledcatheter shaft810. Thestiffness catheter shaft810 andtip800 can be configured to facilitate safe placement of thecatheter890 in the spinal canal. The introducer needle for the catheter can be 15 gauge. The introducer needle for the catheter can be 16 gauge. The introducer needle for the catheter can be 17 gauge. The introducer needle for the catheter can be 18 gauge. The introducer needle can be an epidural needle, such as a tuohy needle.
• For embodiments where thehub820 andinjection port850 are attached to the catheter shaft810 (either separably as in the case wherehub820 andport850 are an injection adaptor port, or inseparably as in the case where thehub820 andport850 are inseparable attached to the catheter shaft810), the length of theelectrode860 can be configured so that when theelectrode860 is fully inserted into thecatheter890, the electrode'sdistal end863 contacts the inner surface of thedistal end805 of thecoil801. One advantage of this configuration is that it provides tactile physical feedback the user that theelectrode860 is fully inserted in thecatheter890. For embodiments where thehub820 andinjection port850 are attached to the catheter shaft810 (either separably as in the case wherehub820 andport850 are an injection adaptor port, or inseparably as in the case where thehub820 andport850 are inseparable attached to the catheter shaft810), the length of theelectrode860 can be configured so that when theelectrode860 is fully inserted into thecatheter890, the electrode'sdistal end863 cannot contact the inner surface of thedistal end805 of thecoil801. For example, as shown inFIG. 8B, thehub861 of theelectrode860 can abut a surface of theport850 to prevent further advancement of theelectrode shaft862 to thecatheter shaft810. One advantage of this configuration is that it ensures the distal end of thecatheter890 remains floppy irrespective of the position of theelectrode860 in thecatheter890. For embodiments where thehub820 andinjection port850 are not attached to thecatheter shaft810 and theelectrode860 is inserted directly in the proximal end of thecatheter shaft810, the length of theelectrode860 can be configured so that when theelectrode860 is fully inserted into thecatheter890, the electrode'sdistal end863 contacts the inner surface of thedistal end805 of thecoil801. One advantage of this configuration is that it provides tactile physical feedback the user that theelectrode860 is fully inserted in thecatheter890. For embodiments where thehub820 andinjection port850 are not attached to thecatheter shaft810 and theelectrode860 is inserted directly in the proximal end of thecatheter shaft810, the length of theelectrode860 can be configured so that when theelectrode860 is fully inserted into thecatheter890, the electrode'sdistal end863 cannot contact the inner surface of thedistal end805 of thecoil801. One advantage of this configuration is that it ensures the distal end of thecatheter890 remains floppy irrespective of the position of theelectrode860 in thecatheter890.
• FIG. 9 presents a catheter electrode system comprising acatheter990 and separate,movable stylet electrode960, in accordance with one aspect of the present invention.FIG. 9A presents one embodiment of the injection electrode system in an external view.FIG. 9B presents one embodiment of the internal construction of the injection electrode system, wherein thecatheter990 is shown in a cross-sectional view and theelectrode960 is shown from its exterior, positioned within thecatheter990. Referring to bothFIG. 9A andFIG. 9B, thecatheter990 comprises atip comprising coil901 anddistal end905,shaft910 comprisinginsulation911 outside thecoil901. Theelectrode960 comprisesshaft962,hub960,cable930,generator connector940 comprisingbody941 and pins942 and943. In some embodiments, theelectrode960 can be fully withdrawn from thecatheter990. The distal end of thecatheter990 is the end of thedistal point905, and the proximal end of thecatheter990 is end into which theelectrode960 can be inserted. Catheter structures that are more distal are closer to thedistal tip905. Catheter structures that are more proximal are closer to the end into which theelectrode960 can be inserted. The distal end of thestylet electrode960 is thedistal tip963. The proximal end of thestylet electrode960 is thehandle961.
• In some embodiments, the catheter electrode system presented inFIG. 9A andFIG. 9B has the same construction and function as the injection electrode system presented inFIG. 8A andFIG. 8B. In some embodiments, the construction and function of the system presented inFIG. 9 is the same as that presented inFIG. 8 with the difference that thehub820 andport850 are not explicitly shown inFIG. 9. It is understood that in some embodiments, an injection adaptor, for instance a tuohy-borst adaptor orremovable injection hub820 and850, can be attached to the proximal end of thecatheter990 to provide for injection of fluids. In one embodiment, thecatheter990 is an epidural catheter, familiar to one skilled in the art of epidural anesthesia. In one embodiment, thecatheter990 is an epidural catheter constructed using a metal coil. In one embodiment, theelectrode960 is a radiofrequency electrode configured to move through the inner lumen of thecatheter990. In one embodiment, theelectrode960 is configured to deliver electrical signals, such as radiofrequency, pulsed radiofrequency, and stimulation signals, to theactive tip900 of the catheter. In one embodiment, electrical signals delivered to theelectrode960 by connection of itsgenerator connector940 to an electrical generator, are in turn conducted to theactive tip900 ofcatheter990 by contact between theelectrode shaft962 with the inner surface of thecoil901.
• Referring now specifically toFIG. 9B, in one embodiment of the injection electrode system, thecatheter990 has asafety strap980 connected to the proximal end of thecoil901 atjunction984 and to the distal end of thecoil901 atjunction981. Thejunction984 can be a weld, such as a laser weld. Thejunction981 can be part of the weld, such as a laser weld or an electrical discharge weld, that forms theclosed end805 of thecatheter990. Thesafety strap980 can be configured to prevent thecoil901 from uncoiling during use. The safety strap can be a metal wire. The safety strap can be a flat wire. The safety strap can be configured to have a low profile to allow entry of the stylet electrode'sshaft962 into the inner lumen of thecoil901. The safety strap can be configured to have a low profile to maintain an open cross-sectional area within the inner lumen of the coil for the flow of injected and aspirated fluid. In embodiments where thesafety strap980 is a metal wire, the safety strap can improve faithful conduction of electrical signals delivered by theelectrode960 to theactive tip900 of thecatheter990. In one embodiment, theelectrode960 can be long enough that itsdistal end963 contacts the innerdistal surface905 of thecatheter990 when it is fully inserted into thecatheter990. In one embodiment, theelectrode960 is configured such that itsdistal end963 does not contact the inner surface of thedistal end905 of thecatheter990, when theelectrode960 is fully inserted into thecatheter990. For example, as shown inFIG. 9B, thehub961 of theelectrode960 can be constructed to abut the proximal end of thecatheter890 and thereby prevent thedistal end963 of theelectrode shaft962 from contacting the distal end of the inner lumen of thecoil901.

Claims (42)

1. A unitized system, comprising:

a flexible electrode having a shaft and the shaft of the electrode has a proximal end and distal end, the proximal end being electrically insulated, and the distal end being electrically uninsulated;

an injection port inseparably coupled to the flexible electrode;

a temperature sensor at the distal end of the electrode that measures the temperature at the tip of the electrode; and

an electrical connector inseparably coupled to the flexible electrode;

wherein the unitized system is a one-piece device joined by gluing, welding, soldering, crimping, hooking, or mechanical locking that is configured to deliver injected fluids and electrical signal to a target tissue at the same time.

2. The device ofclaim 1, wherein the electrode is configured for placement in the spinal canal.

3. The device ofclaim 1, wherein the electrode is configured for placement in the epidural space.

4.-6. (canceled)

7. The device of claim6, wherein the electrical connector is coupled to an electrical supply that provides an electrical signal and a temperature signal from the temperature sensor is used to control the electrical signal from the electrical supply.

8. The device inclaim 7, wherein the electrical signal is a radiofrequency signal.

9. The device inclaim 8, wherein the electrical signal is a pulsed radiofrequency signal.

10. The device inclaim 7, wherein the electrical signal is a nerve stimulation signal.

11. The device in claim5, wherein the electrode shaft comprises a metallic coil that has a proximal end covered by an electrically-insulative material.

12. The device inclaim 11, wherein the metallic coil is a stainless steel spring coil.

13. The device inclaim 11, wherein the electrically-insulative material is a plastic tube.

14. The device inclaim 13, wherein the plastic tube is a heat-shrinkable tube.

15. The deviceclaim 11, wherein the distal end of the coil is closed by a weld.

16. The deviceclaim 15, wherein the weld is a temperature sensor.

17. The device ofclaim 16, wherein the electrical connector is coupled to an electrical supply that provides an electrical signal and a temperature signal from the temperature sensor is used to control an electrical signal from the electrical supply.

18. The device inclaim 1, wherein fluids injected into the injection port outflows through the distal end of the electrode.

19. The device inclaim 11, wherein a wire within the lumen of the coil is connected to the coil at both the distal and proximal ends of the coil.

20. A unitized injection electrode with a proximal and a distal end comprising the following inseparably connected elements:

a metallic coil;

electrical insulation that covers the proximal end of the coil and leaves the distal end of the coil uninsulated;

an injection port connected to the proximal end of the coil and configured such that fluid injected into the port flows out of the uninsulated distal end of the coil;

a temperature sensor at the distal end of the electrode that measures the temperature at the tip of the electrode;

an electrical connector configured so that an electrical signal delivered to the electrical connector is delivered to tissue in contact with the uninsulated distal end of the coil;

wherein the unitized injection electrode is a one-piece device joined by gluing, welding, soldering, crimping, hooking, or mechanical locking that is configured to deliver injected fluids and electrical signal to a target tissue at the same time.

21. The device inclaim 20, wherein the electrical signal is a radiofrequency signal.

22. The device inclaim 20, wherein the electrode is configured for placement in the epidural space.

23. The device inclaim 20, wherein the distal end of the coil is closed by a weld.

24. (canceled)

25. The device inclaim 20, wherein a metal rod within the lumen of the coil is connected at both the distal end of the coil and to the proximal end of the coil.

26. The device inclaim 23, wherein the weld captures thermocouple wires to form a thermocouple temperature sensor, the weld captures the distal end of a metal rod that is also connected to the proximal end of the coil, and temperature signals from the temperature sensor can be measured by connection to a temperature connector that is inseparably attached to the electrode.

27. The device inclaim 20, wherein the coil is a stainless steel coil.

28. The device inclaim 20, wherein the coil is a stainless steel coil made from round wire.

29. The device inclaim 20, wherein the electrical connector also includes connectors to the temperature sensor.

30. A flexible catheter with a metallic tip and an electrode configured to be placed within the lumen of the catheter.

31. The device inclaim 28 wherein the catheter has an electrically insulated proximal end and an uninsulated distal end, so that electrical signals delivered to the electrode are delivered to tissue in contact with the uninsulated distal end of the catheter.

32. The device inclaim 29 where the catheter is an epidural catheter.

33. The device inclaim 28 where the electrode is a radiofrequency electrode.

34. The device inclaim 29 where the electrode has a temperature sensor that can be positioned in the uninsulated active tip of the catheter when the electrode is inserted into the electrode.

35. A catheter delivery device to transmit radiofrequency energy to a spinal canal, comprising:

a needle having an open proximal end and an open distal end, and a lumen that extends from the open proximal end to the open distal end;

a catheter having a blunt, metallic tip on a distal end of the catheter that transmits a radio frequency energy to the treatment site, wherein the catheter is telescopically disposed within the needle lumen to allow the tip to be maneuverably positioned within the spinal canal;

a catheter hub coupled to a proximal end of the catheter;

a metallic wire element telescopically disposed within a lumen of the catheter;

and an adapter hub coupled to a proximal end of the wire element;

wherein the adapter hub is cooperatively engageable to the catheter hub to form a single shaft,

wherein a proximal end of the adapter hub is configured couple to a radio frequency generating device,

wherein the adapter hub and the catheter hub are sized and dimensioned relative to one another such that engagement of the adapter hub to the catheter hub prevents the distal end of the wire element from touching a seating surface of the tip, and

wherein the wire element contacts metallic elements inside the length of the catheter lumen so that the wire element delivers a radio frequency energy from the radio frequency generating device to the tip.

36. The device ofclaim 33, wherein a length of the catheter is longer than a length of the needle.

37. The device ofclaim 33, wherein the catheter is flexible.

38. The device ofclaim 33, further comprising a layer of insulating material coupled to a portion of the catheter, wherein the insulating material prevents a radio frequency energy from transmitting.

39. The device ofclaim 36, wherein the insulating material encapsulates all but the distal end of the catheter.

40. The device ofclaim 35, wherein the insulating material terminates 10 mm from the distal end of the catheter.

41. The device ofclaim 33, wherein a portion of the catheter is not straight to improve steerage of the catheter.

42. The device ofclaim 33, wherein the distal end of the needle is sharpened to penetrate an outer layer of the treatment site.

43. The device ofclaim 33, wherein the distal end of the wire element and the seating surface of the tip are formed to have complementary configurations to facilitate the engagement between the distal end of the wire element and the seating surface of the tip.

44. The device ofclaim 36, wherein the catheter's distal end is constructed from a metallic coil, the proximal end of which is covered by an electrically-insulative material.

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