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Over-the-wire high frequency electrodeRelated Patent Categories: Surgery, Instruments, Electrical Application, ApplicatorsOver-the-wire high frequency electrode description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060178666, Over-the-wire high frequency electrode. Brief Patent Description - Full Patent Description - Patent Application Claims
CLAIM OF PRIORITY [0001] This application is a continuation of U.S. patent application Ser. No. 10/058,967, filed on Jan. 30, 2002, allowed, which claims priority to U.S. Provisional Application No. 60/310,438, filed on Aug. 3, 2001, the entire contents of which are hereby incorporated by reference. TECHNICAL FIELD [0002] This invention relates generally to the advances in medical systems and procedures for prolonging and improving human life. More particularly, this invention relates to an improved method and system involving a high frequency electrode that is inserted into the human body over a guide wire for performing thermal high frequency ablation of target tissue such as cancerous tumors. BACKGROUND [0003] The use of high frequency electrodes for heat ablation treatment of functional disease and in the destruction of tumors is well known. One example is the destruction of cancerous tumors of the kidney using radio frequency (RF) heat ablation. A paper by D. W. Gervais, et al., entitled "Radio-frequency Ablation of Renal Cell Carcinoma: Early Clinical Experience," Radiology, vol. 217, no. 2, pp. 665-672 (2000) describes using a rigid tissue perforating and penetrating electrode that has a sharpened tip to self-penetrate the skin and tissue of the patient. This paper is hereby incorporated by reference herein in its entirety. The exposed conductive tip of the electrode is placed in the tumor within the kidney. The electrode has cooling fluid circulating within it to enable larger ablation volumes to be made. Such rigid, cooled, tissue-perforating radio frequency electrodes are available from Radionics, Inc., Burlington, Mass. [0004] The theory behind and practice of RF heat ablation has been known for decades and a wide range of suitable RF generators and electrodes exists. For example, equipment for causing heat lesions is available from Radionics, Inc., located in Burlington, Mass. [0005] A research paper by E. R. Cosman, et al., entitled "Theoretical Aspects of Radiofrequency Lesions in the Dorsal Root Entry Zone," Neurosurgery, Vol. 15, No. 6, pp. 945-950 (1984) describes various techniques associated with radio frequency lesions and is hereby incorporated by reference herein in its entirety. Also, research papers by S. N. Goldberg, et al., entitled "Tissue Ablation with Radio Frequency: Effect of Probe Size, Gauge, Duration, and Temperature on Lesion Volume," Acad. Radiol., Vol. 2, pp. 399-404 (1995), and "Thermal Ablation Therapy for Focal Malignancy," AJR, Vol. 174, pp. 323-331 (1999) describe techniques and considerations relating to tissue ablation with radio frequency energy and are hereby incorporated by reference herein in its entirety. SUMMARY [0006] In one aspect, a device for ablating tissue in the living body includes an elongate member defining a longitudinal passage having a distal opening and a proximal opening dimensioned to pass a guide element. The elongate member includes an electrode disposed at a distal portion of the elongate member and configured to be energized with high frequency energy to ablate tissue. [0007] In another aspect, a device for ablating tissue includes a rigid elongate tubular member defining a longitudinally extending lumen having a distal opening and a proximal opening. The lumen is dimensioned to pass along a guide element. A distal portion of the tubular member has a blunt distal tip. The device also includes an electrode disposed at a distal portion of the tubular member and configured to be energized with high frequency energy to thermally ablate tissue, and a fluid channel defined within the tubular member, the fluid channel in fluid communication with the fluid input port and the fluid output port and in thermal communication with the electrode. [0008] In another aspect, a device for ablating tissue includes a flexible elongate tubular member defining a longitudinally extending lumen having a distal opening and a proximal opening. The lumen is dimensioned to pass along a guide element. A distal portion of the tubular member has a blunt distal tip. The device also includes an electrode disposed at a distal portion of the tubular member and configured to be energized with high frequency energy to thermally ablate tissue, and a fluid channel defined within the tubular member, the fluid channel in fluid communication with the fluid input port and the fluid output port and in thermal communication with the electrode. [0009] In another aspect, a system for ablation of a tissue in the living body includes a guide element and an ablation system. The ablation system includes an elongate member defining a longitudinal channel having a distal opening and proximal opening, the elongate member being dimensioned to slide along the guide element. The ablation system also includes an electrode at a distal portion of the elongate member and configured to be energized with high frequency energy to ablate the tissue. The system can also include a needle element defining a longitudinal lumen dimensioned to pass the guide element. The needle can include a sharp distal tip configured to perforate the tissue. The elongate member can define a fluid channel in fluid communication with a fluid input and a fluid outlet and in thermal communication with the electrode. The ablation system can also include a high frequency generator, electrical conductors connecting the high frequency generator to the electrode, a fluid agent injector, or a coolant supply connected to a fluid input of the elongate member. [0010] The elongate member can be rigid or flexible. The elongate member can include a blunt distal tip. The blunt distal tip can converge smoothly with the distal opening. The blunt distal tip can include a rounded contour surrounding the distal opening. The blunt distal tip can include a tapered contour converging with the distal opening. The blunt distal tip can include a fluid sealed junction between the metal tube and the inner metal tube. [0011] The device can include a fluid inlet port and a fluid outlet port. The elongate member can further define a fluid channel in fluid communication with the fluid inlet port and the fluid outlet port. The fluid channel can be in thermal communication with the electrode. [0012] The electrode can include an exposed portion of the external surface of the outer metal tube. The electrode can include a metal element. The electrode can be a ring. The electrode can include a tapered contour converging with the distal opening. [0013] The tubular member can include a metal tube having an external surface and an electrical insulator configured to electrically insulate a portion of the external surface of the metal tube. The tubular member can include a plastic tube. The device can include an inner metal tube disposed within the metal tube and defining a portion of the lumen. The fluid channel can be located at least in part between the metal tube and the inner metal tube. [0014] The guide element can include a flexible guide wire or a rigid stylet wire. The guide element comprises an anchor that extends laterally from a distal guide portion of the guide element. The anchor can be configured to anchor the distal guide portion near a target. The guide element can include a tube containing a movable member. The movable member can be a tube or an anchor. [0015] In another aspect, a method for thermal ablation of a target volume includes perforating and penetrating a living body using a guide element to establish a tract through the body to the target volume, sliding an electrode along the guide element to position the electrode near the target volume, connecting the electrical connection to a high frequency generator, and supplying high frequency energy from the generator through the electrode to the target volume to thermally ablate the target volume. The electrode includes an elongate member defining a longitudinal passage dimensioned to pass along the guide wire, a conductive surface at a distal portion of the elongate member, and an electrical connection between the conductive surface and a proximal portion of the elongate member. [0016] The method can also include cooling the electrode while supplying high frequency energy to change a spatial distribution of heat near the electrode. Cooling can include connecting a source of a coolant to a fluid input and causing a coolant to flow in a fluid channel in the elongate member. The fluid channel can be fluid communication with the fluid input and a fluid output and in thermal communication with the electrode. Perforating and penetrating can include passing a sharp needle through skin and tissue. Positioning can include passing the guide wire through the needle and removing the needle over the guide wire to leave the guide wire in the tract. Positioning can include deploying an anchor from the guide wire to anchor the guide wire in the tract. The method can also include dilating the tissue along the tract after positioning the guide wire by passing a dilating element over the guide wire to expand the tissue along the tract prior to sliding the electrode along the guide wire. [0017] In certain circumstances, the method can include introducing a fluid agent through the guide element. For example, the method can include introducing a chemotherapeutic agent through the guide element prior to or while supplying high frequency energy. The chemotherapeutic agent can act in combination with the step of supplying high frequency energy to enlarge the volume of ablation. [0018] Advantages of the device can include its use in minimally invasive ablation techniques with better guidance and with less trauma to tissue. A guide wire or stylet that punctures and perforates tissue can have a small diameter, producing less trauma and making device placement easier. Guide wire placements using needles are well known to radiologists and are well adapted to image-guided techniques. Guide wires can be placed in any deep organ or any tissue type without displacing the organ or losing target position. Guide wires can also be configured to anchor to target tissue and hold the device in position at the target despite body organ movement. [0019] A guide wire-guided RF electrode need not itself perforate, cut, or puncture skin or tissue. A guide wire-guided RF electrode can include a blunt distal tip that gently expands and dilates tissue without cutting when the electrode slides over the guide wire. Gentle expansion and dilation of tissue reduces risk of bleeding, since tissue is laterally and frontally compressed during the process, which can be advantageous in vascular target sites such as the kidney where the risk of ripping critical blood vessels is reduced by a dull or rounded electrode tip. [0020] An electrode with a guidance channel through it also allows agents, such as anesthetics, saline loaded fluids, gels, or chemotherapeutic agents, to be injected through the channel to the target site to ease device insertion or enlarge the ablation volume. Continue reading about Over-the-wire high frequency electrode... Full patent description for Over-the-wire high frequency electrode Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Over-the-wire high frequency electrode patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Over-the-wire high frequency electrode or other areas of interest. ### Previous Patent Application: Circuit for controlling arc energy from an electrosurgical generator Next Patent Application: Radio frequency ablation system with integrated ultrasound imaging Industry Class: Surgery ### FreshPatents.com Support Thank you for viewing the Over-the-wire high frequency electrode patent info. 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