Abstract: An instrument for large-area ablation of the mucosa including at least one first gas supply line and at least one second gas supply line whose distal ends are arranged to form an acute angle (?), so that the ends diverge distally. A free space between the distal ends of the gas supply lines allows the user to view the tissue region behind the distal end of the instrument. Due to the acute angle (?), electrodes arranged at least partially in the ends of the gas supply lines generate a wide plasma beam with which the mucosa ablation can be performed. The instrument can be guided precisely due to the view through the free space. A connecting element according to the invention is provided for attaching the ends of the gas supply lines.

Abstract: One embodiment of the present invention relates to an electrosurgical device for conducting surgery. The device includes a tubular housing and a plurality of electrodes disposed within said tubular housing. The device further includes an actuator connected to the plurality of electrodes to extend and retract at least one of the plurality electrodes to and from the tubular housing.

Abstract: Systems and methods for non-thermal ablation of tissue are provided. A non-implantable minimally invasive system for treatment of tissue in a body via direct current ablation is provided. A catheter for use in such system is further provided. The catheter includes a tubular body having a proximal end, a distal end, and a tip positioned at the distal end. The tubular body is semi-flexible, bi-directionally torqueable, and chemically resistant. The tubular body includes a plurality of routing holes provided between the proximal end and the distal end for facilitating deployment of electrodes from the tubular body. The tubular body further comprises an inner sheath generally at an interior portion and an outer sheath generally at an exterior portion and being chemically resistant.

Abstract: An electrode array and a delivery assembly are disclosed. The array is wrapped around a flexible core part of the delivery assembly. A sheath, also part of the delivery assembly, is disposed over the array and core. Steering cables extend through the core. Once the delivery assembly-encased array is inserted in the body, the combination is advanced to the tissue over which the array is to be deployed. By pulling on the steering cables the array and assembly are steered into position. Once the array is in position, the sheath is retracted, the array deploys over the target tissue.

Abstract: Devices, systems and/or methods for repairing soft tissue adjacent a repair site. In one embodiment, a repair device is delivered with a delivery device system configured to move a cartridge with the repair device disposed therein toward an anvil with soft tissue positioned thereon. The delivery device linearly moves the cartridge toward the anvil with a worm drive positioned within a housing by rotating a thumb wheel disposed around the worm drive. Such linear movement is provided with a finger element extending from the worm drive that is configured to cooperate with an internal surface of the thumb wheel. With this arrangement, upon rotating the thumb wheel, the worm drive rotates with the finger element engaged with the internal surface of the thumb wheel to linearly move the cartridge toward the anvil.

Abstract: Transducer-based systems and methods may be configured to display a graphical representation of a transducer-based device, the graphical representation including graphical elements corresponding to transducers of the transducer-based device, and also including between graphical elements respectively associated with a set of the transducers and respectively associated with a region of space between the transducers of the transducer-based device. Selection of graphical elements and/or between graphical elements can cause activation of the set of transducers associated with the selected elements. Transducer activation characteristics, such as initiation time, activation duration, activation sequence, and energy delivery characteristics, can vary based on numerous factors. Visual characteristics of graphical elements and between graphical elements can change based on an activation-status of the corresponding transducers.

Abstract: Certain aspects relate to systems and techniques for an articulating monopolar medical instrument. In one aspect, the medical instrument includes a wrist comprising a proximal clevis and a distal clevis; an end effector coupled to the distal clevis via a distal axle; at least one proximal pulley in the proximal clevis; at least one distal pulley in the distal clevis and coupled to the distal axle; a first cable configured to engage with the at least one proximal pulley and the at least one distal pulley; and a second cable configured to engage with the at least one proximal pulley without engaging the at least one distal pulley.

Abstract: Methods for treating tissue with irreversible electroporation and immunotherapy are described. The methods include placing a probe in tissue within a human body, wherein the probe has at least a first electrode, applying a plurality of electrical pulses through the first electrode and a second electrode, causing irreversible electroporation (IRE) of the tissue within a target ablation zone, and administering one or more exogenous agents into the tissue within the target ablation zone or to the human, thereby stimulating or otherwise modulating an immune system response within the body.

Abstract: Electrosurgical wands. At least some of the illustrative embodiments are electrosurgical wands having features that reduce contact of tissue with an active electrode of a wand, decrease the likelihood of clogging, and/or increase the visibility within surgical field. For example, wands in accordance with at least some embodiments may comprise standoffs, either along the outer perimeter of the active electrode, or through the main aperture in the active electrode, to reduce tissue contact. Wands in accordance with at least some embodiments may implement slots on the active electrodes to increase bubble aspiration to help keep the visual field at the surgical site clear. Wands in accordance with at least some embodiments may implement aspiration flow pathways within the wand that increase in cross-sectional area to reduce the likelihood of clogging.

Abstract: A catheter with a variable circular loop responsive to a contraction wire for coiling is supported by a member having a tapered distal section that transitions from a circular cross-section to a generally rectangular cross-section while maintaining a uniform cross-sectional area along the entire tapered length for improved coiling characteristics. A radially constrictive sleeve prevents separation of the contraction wire from the support member to minimize misshaping of the loop during contraction.

Abstract: An ablation probe is provided. The ablation probe includes a housing that is configured to couple to a microwave energy source. A shaft extends distally from the housing and includes a radiating section at a distal end thereof. A sensor assembly is operably disposed on the housing and includes a pair of sensor contacts. One or more sensors are positioned adjacent the radiating section and extend along the shaft. The sensor(s) have a pair of sensor contact pads that are positioned on the shaft for contact with the pair of sensors such that during transmission of microwave from the radiating section into target tissue at least one electrical parameter is induced into the at least one sensor and detected by the pair of sensor contacts.

Abstract: Methods for treating tissue with irreversible electroporation and immunotherapy are described. The methods include placing a probe in tissue within a human body, wherein the probe has at least a first electrode, applying a plurality of electrical pulses through the first electrode and a second electrode, causing irreversible electroporation (IRE) of the tissue within a target ablation zone, and administering one or more exogenous agents into the tissue within the target ablation zone or to the human, thereby stimulating or otherwise modulating an immune system response within the body.

Abstract: A catheter has a two-piece tip electrode with a shell and a support structure that are secured to each other by multiple redundant mechanisms in order to reduce the risk of tip detachment during a procedure. The tip electrode includes at least two different welds attaching the shell to the support structure to provide a dual failure mode. One weld includes a seam weld and another weld includes a penetration weld.

Abstract: A variety of methods for managing a re-usable ultrasonic medical device may include a medical device control module capable of receiving functional data from a user assembled or reassembled ultrasonic medical device, and notifying the user if a value of the functional data lies within an acceptance range. If the value of the functional data does not lie within the acceptance range, the control module may prompt a user to reassemble the device or to clean or replace one or more components thereof. The functional data may relate to a clamp force of a jaw assembly, an impedance or resonant frequency value of an ultrasonic blade, or a mechanical displacement value of one or more moving components of the device.

Abstract: A deflectable device, such as a catheter, is provided that includes a hinge that enhances the ability of the device to deflect or bend within a predetermined plane. The catheter comprises an elongated tubular catheter body having proximal and distal ends and at least one lumen extending therethrough. A distal segment is provided distal to the distal end of the catheter body. A tubular hinge is provided between the distal end of the catheter body and the proximal end of the distal segment. The hinge has an axis and at least one lumen extending therethrough. The tube includes at least one slot, and preferably a plurality of slots, extending part of the way through the hinge generally transverse to the axis of the hinge.

Abstract: A method of identifying gaps between electrophysiology (EP) ablation points may comprise: obtaining a plurality of ablation points recorded from a completed electrophysiology ablation procedure; digitally mapping the plurality of ablation points to an anatomical model corresponding to the completed electrophysiology ablation procedure; calculating ablation gap probability distributions for each of the plurality of ablation points based on ablation tolerance variables associated with each of the plurality of ablation points; and overlaying the ablation gap probability distributions on to the digitally mapped plurality of ablation points on the anatomical model. In this way, ablation gaps may be non-invasively identified prior to patient discharge, thereby allowing for further EP treatment to remove the ablation gaps while reducing readmission rates.

Abstract: Partially insulated focused ablation (PIFA) catheters using thermally conductive materials have differential radiofrequency (RF) heating and thereby allow for tailored RF application. Open-irrigated, 4 mm, and 8 mm RF ablation catheters were partially insulated by coating half their surfaces with a layer of vinyl, silicone, vinyl-silicone, polyurethane, or a composite of aluminum oxide/boron nitride (AOBN). RF ablation using catheter tips partially coated with a thermally conductive insulation material such as AOBN results in larger ablation lesion volumes without being limited by standard temperature controls. Partial insulation of the catheter tip is able to protect adjacent critical structures during in vivo ablation.

Abstract: Embodiments of medical treatment including skin treatment using electrical energy, especially with the primary purpose for skin treatment for aesthetics are described generally herein. Other embodiments may be described and claimed.

Abstract: Tissue regions are treated using a multiple lead electrode probe. A plurality of electrodes may be disposed about an elongate shaft. The elongate shaft may be slidably disposed within a lumen of a delivery sheath. One or more probes including one or more electrically active regions may also be slidably disposed within the delivery sheath. The one or more probes may be configured to extend radially about the elongate shaft. The plurality of electrodes and the electrically active regions may be individually connected to a control and power unit through individual channels.

Abstract: Catheter apparatuses and methods are provided for repairing heart valves, particularly mitral valves. The method includes providing a catheter having an elongate, flexible body, with a proximal end and a distal end. The distal end can be transluminally advanced from the left atrium through the mitral valve. A distal anchor zone or portion coupled with the proximal end can extend and along the left ventricular outflow tract into the ascending aorta. A valve repair device is deployed to permanently connect leaflets at a mid-section of a mitral valve while permitting medial and lateral portions of the natural leaflets to open and close. The catheter apparatuses may be positionable using a steering device. The valve repair device detachably connects the distal and proximal ends of the catheter. The valve repair device can be detached using low profile devices actuatable from the proximal or distal ends, e.g., at a venous or arterial access site.

Abstract: The invention relates to an energy application apparatus for applying energy to an object. A plurality of energy application elements (4) applies energy to the object at different locations and at least one ultrasound element (18) generates an ultrasound signal being indicative of a property of the object at the different locations, wherein at least one energy application element is individually controlled depending on an energy application influence, in particular, an ablation depth, determined for the location at which the at least one energy application element applies energy from the ultrasound signal. Thus, at least one local control point for applying energy to the object is provided, thereby improving the control of applying energy to the object.

Abstract: The methods disclosed herein are directed towards improving ablation efficiency associated with applying nanosecond electric pulses (nsEP) to tissue. In particular, applying nsEP to tissue can open pores in the cellular membranes of the tissue. These pores can be kept open longer by cooling the tissue. The combined application of nsEP and the cooling of tissue may have synergistic effects on triggering apoptosis of cells in the tissue. This allows for numerous practical benefits associated with nsEP-based tissue ablation to be realized. For instance, nsEP of lower pulse strength or lower numbers of pulses to be used, which can be provided by smaller pulse generators operating on less power.

Abstract: Helical push wire electrodes are provided. The electrodes may create a continuous helical lesion. One or more electrodes may wind around a support section and create a set of helixes having fixed ends and hitches. Pushing or pulling an end of the electrode transforms the electrodes between a delivery configuration and a deployed configuration such that the set of helixes expand or contract axially. Different portions of the electrodes may be surrounded by sleeves. The sleeves may regulate how the wires transform and provide insulation. Various insulation configurations of the electrodes may provide creations of discrete lesions, efficient energy delivery and reduced power consumption.

Abstract: A radiofrequency denervation device with a needle and an electrode for actuating an active portion of the needle to produce radiofrequency denervation of the sacroiliac joint. The needle has a tip with an inactive portion and the radiofrequency active portion for producing lesions in surrounding tissue. The active portion and a portion of the inactive portion are disposed in a helical formation concentric with a longitudinal axis of the needle. The helical formation communicates over an arcuate path with an angle of attack. A method of radiofrequency denervation can be performed by rotating the tip of the needle in a screw-like motion in a first rotational direction to achieve a position with the active portion of the tip substantially parallel to a surface of the sacrum and actuating the active portion to produce a lesion. Repositioning and further lesioning can be achieved by selective rotation and actuation of the tip.

Abstract: Tumors can be treated with an alternating electric field. The size of cells in the tumor is determined prior to the start of treatment by, for example, biopsy or by inverse electric impedance tomography. A treatment frequency is chosen based on the determined cell size. The cell size can be determined during the course of treatment and the treatment frequency is adjusted to reflect changes in the cell size. A suitable apparatus for this purpose includes a device for measuring the tumor impedance, an AC signal generator with a controllable output frequency, a processor for estimating the size of tumor cells and setting the frequency of the AC signal generator based thereon, and at least one pair of electrodes operatively connected to the AC signal generator such that an alternating electric field is applied to the tumor.

Abstract: A medical device is disclosed, including a handle assembly; an elongate body coupled to the handle assembly, the elongate body defining a guide wire lumen therethrough; and a substantially semi-circular electrode array coupled to the elongate body. The device may include a substantially rigid shaft extending distally from the elongate body and defining a lumen therethrough, the shaft including a substantially rigid segment, and a flexible coil coaxial with and extending distally from the shaft.

Abstract: Systems and methods are disclosed for providing and using an irrigated ablation catheter. The catheter includes a distal electrode assembly having a plurality of spines forming a basket shaped electrode assembly in communication with a system controller. The catheter also includes a pull-wire disposed within a lumen of a spine collar. The spine collar further includes a silicone seal for preventing encroachment of irrigation fluid and other bodily fluids into the pull-wire lumen.

Abstract: Methods and apparatus for measuring pressure in a patient are provided which may include any number of features. One feature is a pressure measurement system comprising a pressure source, a compliant bladder, a catheter in communication with the pressure source, pressure sensors, and a controller configured to determine a pressure within the compliant bladder. The pressure measurement system can inflate the compliant bladder with gas or air to determine a pressure within a patient. In one embodiment, the pressure measurement system measures pressure within a peritoneal cavity.

Abstract: A surgical instrument having an end effector mounted on the end of an elongate shaft extending from a handle is described, the shaft and end effector being rotatable with respect to the housing, to allow different rotational orientations of the end effector to be attained without rotating the whole instrument. To provide for control over the degree of rotation, shaft rotation control elements are provided to give rotation or torsion control. The shaft rotation control elements may be located at several different longitudinal positions along the shaft. Alternatively, rotation control elements in the form of mutually co-operating stops may be provided elsewhere, such as in a rotatable shaft support member at the distal end of the handle. In other embodiments rotation control stops are provided on both elements, thus providing for effective rotation control, which has a high quality feel to the user.

Abstract: A method for ablating a uterine endometrium enlarges an expandable-contractible frame to expand a compliant energy-delivery surface into a planar triangular shape and engage the surface against the walls of a patient's uterine cavity. The frame has flexible outer elements in lateral contact with the compliant surface and flexible inner elements not in said lateral contact, wherein the inner flexible element and outer flexible elements have substantially dissimilar material properties. Energy is applied through the compliant energy-delivery surface to ablate the endometrium.

Abstract: An electrode assembly (3) is provided for use in a resectoscope, the electrode assembly (3) comprising a pair of arms (4), and a tissue treatment element (9) depending from the arms. The arms (4) are pivotably mounted one to the other such that they are movable between a retracted position in which they lie alongside one another and a deployed position in which they diverge one from another. The electrode assembly (3) includes actuation means for moving the arms between their retracted and deployed positions. The tissue treatment element (9) is disposed at the distal end of each arm such that it is movable between at least two different operating positions.

Abstract: A surgical device for sensing a tissue property includes a handle, an outer cannula, an actuation assembly, and a sensing assembly. The handle is coupled to the outer cannula. The actuation assembly is slidably received by the outer cannula. The sensing assembly includes a fixed member, a shuttle, a sensor, and a bladder. The fixed member is disposed along a distal portion of the outer cannula. The shuttle is configured to slidably engage the fixed member. The sensor is disposed on the shuttle. The bladder is configured to be in fluid communication with the bladder pressurization device.

Abstract: A sliding distal component assembly for use in medical catheters, bioptomes and other medical devices is provided. The sliding distal component assembly includes a tubular shaft having a lumen, the tubular shaft coupled to an actuation mechanism moveable between a first position and a second position. A tip support is coupled to the tubular shaft and defines a tip support cavity therewithin. The sliding component assembly includes a pulley system having at least one pulley, a sliding distal component and at least one pull wire coupled to the pulley and the sliding distal component with at least a portion of said pulley system being housed within said tip support cavity. When the actuation mechanism is in the first position the sliding distal component is configured to translate proximally and when the actuation mechanism is in the second position the sliding distal component is configured to translate distally.

Abstract: Diagnostic and therapeutic medical devices and methods that include an elongate shaft, a balloon, a plurality of electrodes carried by the balloon, and electronics to electrically connect the electrodes to a proximal end of the shaft. The devices can include a visualization system within the balloon.

Abstract: Methods and systems for spinal radio frequency neurotomy. Systems include needles capable of applying RF energy to target volumes within a patient. Such target volumes may contain target medial branch nerves along vertebrae or rami proximate the sacrum. Such procedures may be used to ablate or cauterize a portion of the targeted nerve, thus blocking the ability of the nerve to transmit signals to the central nervous system. Disclosed needles may be operable to asymmetrically, relative to a central longitudinal axis of the needle, apply RF energy. Such asymmetry facilitates procedures where a tip of the needle is placed proximate to anatomical structures for location verification. Then RF energy may be applied in a selectable direction relative to the needle tip to ablate volumes that include the targeted medial branch nerves or rami, thus denervating facet joints or the sacroiliac joint, respectively, to relieve pain in a patient.

Abstract: An insertion device, includes an elongate member having a needle portion and a handle portion. The handle portion includes a visual indicator. The visual indicator is configured to indicate an orientation of the needle portion.

Abstract: Disclosed is a coupling for use in a looped medical device, such as a loop catheter. A sleeve is fitted onto a distal portion of an activation wire and a shape-memory wire is positioned alongside the sleeved activation wire. The sleeve is welded onto the activation wire to hold the sleeve onto the activation wire and is also welded onto the shape-memory wire that is positioned alongside the activation wire, thereby affixing the activation wire to the shape-memory wire. Also disclosed is an activation wire for use in a catheter. The activation wire includes a proximal section, and a distal section having at least a partial loop. The activation wire includes a connection section on the distal section, where the connection section is linear, and where the external surface of the connection section has a higher coefficient of friction than at least some of the remaining portion of the actuation wire that is housed within the catheter shaft.

Abstract: A probe includes a shaft and an applicator head designed to treat irregularly-shaped hollow cavities, such as a cavity in breast tissue created by a lumpectomy procedure. The applicator head has a fixed geometry, and a plurality of electrodes can be advanced from an exterior surface of the applicator head in an omnidirectional pattern. The electrodes are used to deliver radiofrequency current or other energy to ablate the marginal tissue.

Abstract: Monitoring a patient can include a vital sign device including a skin contact and a demodulator circuit in communication with the electrically conductive skin contact, the demodulator circuit including: a physiological waveform data processing module configured to process the waveform data received from the electrically conductive skin contact; and a digitally encoded data processing module configured to detect and decode digitally encoded data modulated at the carrier frequency. Also included can be a signal conductive blanket including an extended touch point. A clinician contacts the extended touch point of the signal conductive blanket and the patient monitoring device to connect the vital sign device and the patient monitoring device.

Abstract: The present disclosure relates generally to medical devices, and more specifically to ablation catheters including bond joints formed to have improved strength and resistance to failure during use. In many embodiments an expanded bond-joint length and area and gap filling are used to increase the strength of the bond joint while decreasing relative variability. The bond joint length area is increased in a controlled manner so as to increase the overall strength of the bond joint by shifting the failure mode from the bond joint to a stronger area of the ablation catheter, such as the catheter shaft. Related methods of manufacturing such ablation catheters (or other medical devices including a bond joint) are also disclosed and described herein.

Abstract: Systems and methods for tissue ablation. Systems include needles with deployable filaments capable of producing asymmetrical offset lesions at target volumes, which may include a target nerve. Ablation of at least a portion of the target nerve may inhibit the ability of the nerve to transmit signals, such as pain signals, to the central nervous system. The offset lesion may facilitate procedures by directing energy towards the target nerve and away from collateral structures. Example anatomical structures include lumbar, thoracic, and cervical medial branch nerves and rami and the sacroiliac joint.

Abstract: A catheter tip electrode has a tissue contacting surface which electrically conducts RF energy to the tissue and is more thermally conductive than adjacent non-electrically conductive coating or cover which prevents RF conduction to the tissue contacting that surface. The tip electrode has a shell with a nonablating hollow proximal neck portion and a distal ablating portion defining a fluid chamber, and a plug-like support member which is configured with a fluid channel on its outer surface so a fluid passage is provided between the member and the neck portion for convective or direct cooling of the nonablating neck portion and nonconductive tubing covering it.

Abstract: Apparatuses, systems and methods are provided for treating pulmonary tissues via delivery of energy, generally characterized by high voltage pulses, to target tissue using a pulmonary tissue modification system (e.g., an energy delivery catheter system). Example pulmonary tissues include, without limitation, the epithelium (the goblet cells, ciliated pseudostratified columnar epithelial cells, and basal cells), lamina propria, submucosa, submucosal glands, basement membrane, smooth muscle, cartilage, nerves, pathogens resident near or within the tissue, or a combination of any of these. The system may be used to treat a variety of pulmonary diseases or disorders such as or associated with COPD (e.g., chronic bronchitis, emphysema), asthma, interstitial pulmonary fibrosis, cystic fibrosis, bronchiectasis, primary ciliary dyskinesia (PCD), acute bronchitis and/or other pulmonary diseases or disorders.

Abstract: A vapor delivery system and method is provided that is adapted for ablating bladder tissue to treat overactive bladder (OAB). The vapor delivery system includes an anchor tip configured anchor the system in the bladder while condensable vapor is delivered to target tissue. In one method, the vapor delivery system is advanced transurethrally into the patient to access the target tissue of the bladder, which can include a surface sensor of the bladder responsible for creating an urge incontinence sensation. The vapor delivery system includes a vapor source that provides a high quality vapor for delivery to tissue.

Abstract: Provided is a medical device for clearing an obstruction from a surgical instrument or surgical site, the device comprising: a first hollow member configured to allow air or inert gas passage; a second hollow member having a distal end and a proximal end, the proximal end configured to be connectable to a vacuum or suction source; a housing member configured to receive both the first hollow member and the second hollow member; and a push button operably connected to the housing member; and an inflation bulb configured to be attachable to the housing member, wherein the push button is configured to disengage the first hollow member and occlude the second hollow member when depressed by a force, and/or wherein the push button and the inflation bulb are configured to be operable by one hand of an operator.

Abstract: Techniques for treating a tumor and vaccinating against cancer are described. The techniques include treating the tumor by positioning electrodes over an interface between the tumor and non-tumor tissue and applying sub-microsecond pulsed electric fields. The positioning is facilitated by an imaginary contour line of a threshold value of the electric field. In an example, the imaginary contour line is overlaid over images that include the tumor such that the electrodes are properly positioned over the tumor. The techniques also include vaccinating against cancer by passing sub-microsecond pulsed electric fields through tumor cells of a subject sufficient to cause the tumor cells to express calreticulin on surface membranes. The tumor cells are extracted and introduced with the expressed calreticulin into the subject or another subject, thereby providing a vaccination.

Abstract: The invention generally relates to systems and methods for therapeutically modulating nerves in or associated with a nasal region of a patient for the treatment of a rhinosinusitis condition.

Abstract: In one general aspect, various embodiments are directed to a surgical instrument that can supply mechanical energy and electrical energy to an end effector of the surgical instrument. The surgical instrument may be operated in a first operating mode in which a transducer of the surgical instrument produces mechanical energy, or vibrations, that are transmitted to the end effector and a second operating mode in which electrical energy, or current, can flow through the end effector to perform electrosurgery. In another general aspect, the surgical instrument may comprise a clamp, or jaw, which can be moved into a closed position to hold tissue against a waveguide, or blade, of the end effector. In the second operating mode of the surgical instrument, current can flow from a power source, through the waveguide, and return to the power source through a path comprising the jaw.

Abstract: According to some embodiments of the invention, a method for providing an atrial fibrillation (AF) ablation treatment plan includes receiving imaging data for at least a portion of an atrial region of a subject's heart, and processing the imaging data to characterize tissue as one of fibrotic tissue or non-fibrotic tissue. The method further includes calculating a metric of spatial distribution of at least a portion of the tissue characterized as fibrotic tissue from the processing the imaging data, identifying a cardiac tissue ablation target based on the metric, and providing an AF treatment plan that includes the cardiac tissue ablation target as at least a portion of the AF treatment plan.

Abstract: An irrigated needle electrode ablation catheter has a distal tip section with a tip electrode, a needle electrode assembly longitudinal movable relative to the catheter, and a needle centering insert in a channel in the tip electrode. The assembly has a proximal tubing and a distal needle electrode, and the insert supports the needle electrode in the channel at a predetermined separation distance from the tip electrode while enabling irrigation to flow circumferentially around the needle electrode through the channel and exit at the distal end of the tip electrode. The catheter also provides a first dedicated fluid pathway through the assembly and exits at the distal end of the needle electrode, and a second dedicated fluid pathway to supply fluid to the channel in the tip electrode, wherein the second pathway is defined by a guide tube and directed by a plunger member.