Patent Application
20070203483
The present invention relates generally to the treatment of tissue of a patient with ablative energy and, more particularly, to the an ablation device having a flexible shaft allowing for ease in surgical placement of the ablation device, and/or having a lockout feature that helps to prevent inadvertent application of ablative energy.
Although the present invention contemplates devices, systems and methods relating to ablation of many types of tissue, in particular, the present application will focus on ablation devices and keys features thereof, systems of guiding or placing ablation devices, and methods of using ablation devices and of guiding ablation devices into a body, for the ablation of heart tissue or tissue near the heart. Also, the present invention contemplates the use of the described ablation devices, systems and methods to treat various conditions, however, the present application will focus particularly on treatment of heart arrhythmias (e.g., atrial fibrillation).
In a normal heart, contraction and relaxation of the heart muscle (myocardium) takes place in an organized fashion as electrochemical signals pass sequentially through the myocardium from the sinoatrial (SA) node located in the right atrium to the atrialventricular (AV) node and then along a well defined route which includes the His-Purkinje system into the left and right ventricles. Sometimes abnormal rhythms occur in the atrium which are referred to as atrial arrhythmia. Three of the most common arrhythmia are ectopic atrial tachycardia, atrial fibrillation, and atrial flutter. Arrhythmia can result in significant patient discomfort and even death because of a number of associated problems, including the following: (1) an irregular heart rate, which causes a patient discomfort and anxiety; (2) loss of synchronous atrioventricular contractions, which compromises cardiac hemodynamics resulting in varying levels of congestive heart failure; and (3) stasis of blood flow, which increases vulnerability to thromboembolism. It is sometimes difficult to isolate a specific pathological cause of the arrhythmia although it is believed that the principal mechanism is one or a multitude of stray circuits within the left and/or right atrium. These circuits or stray electrical signals are believed to interfere with the normal electrochemical signals passing from the SA node to the AV node and into the ventricles.
Treatment of arrhythmias may be accomplished by a variety of approaches, including drugs, surgery, implantable pacemakers/defibrillators, and catheter ablation. While arrhythmic drugs may be the treatment of choice for many patients, these drugs may only mask the symptoms and do not cure the underlying cause. Implantable devices, on the other hand, usually can correct an arrhythmia only after it occurs. Surgical and catheter-based treatments, by contrast, may actually cure the problem usually by ablating the abnormal arrhythmogenic tissue or abnormal pathway responsible for the arrhythmia. The catheter-based treatments rely on the application of various destructive energy sources to the target tissue including direct current energy sources to the target tissue including direct current electrical energy, radiofrequency electrical energy, microwave energy, laser energy, cryoenergy, ultrasound, and the like.
One surgical method of treating atrial fibrillation is the “Maze” procedure, which relies on a prescribed pattern of incisions to anatomically create a convoluted path, or maze, for electrical propagation within the left and right atria. The procedure employs incisions in the right and left atria which divide the atria into electrically isolated portions which in turn results in an orderly passage of a depolarization wave front from the SA node to the AV node, while preventing reentrant wave front propagation. The Maze procedure has been found very effective in curing arrhythmias. However, the procedure is technically difficult. The procedure also requires open heart surgery, in which the breastbone is divided and the surgeon has direct access to the heart.
More recently, Maze-like procedures have been developed utilizing ablation catheters that can form lesions on the endocardium to effectively create a maze for electrical conduction in a predetermined path. Typically, the lesions are formed by ablating tissue with an electrode carried by the catheter. Ablative energy, e.g., high intensity focused ultrasound (HIFU) energy, radiofrequency (RF) energy, microwave energy and/or laser energy, applied to the electrode, causes significant physiological effects in the tissue resulting from thermal and/or mechanical changes or effects. By controlling the energy level, the amount of heat generated in the tissue and the degree of tissue damage or change can also be controlled. Ablation uses lower levels of voltage that creates sufficient heat to cause a desired cell damage, but leaves the tissue structure intact so as to effectively block electrical pathways within the tissue. Irrigation of the electrode(s) during the ablation procedure with saline or other conductive fluid can decrease the interface impedance, cool the tissue, and allow for a greater lesion depth.
A treatment for atrial fibrillation, in particular, includes ablation around the pulmonary veins, which procedure is called pulmonary vein antrum isolation. Almost all the atrial fibrillation signals are believed to come from the four pulmonary veins and move to the atria. Ablation of the area of the atria that connects to the pulmonary veins provides circular scar tissue that blocks impulses firing within the pulmonary veins from moving to the atria, thereby disconnecting the pathway of abnormal rhythm and preventing atrial fibrillation.
Most previous ablation devices have been designed to access the heart via a mid-line sternotomy (i.e., an open surgical procedure). More recently, ablation of cardiac tissue can be carried out through a minimally invasive route, such as between the ribs, through a sub-xyphoid incision or via catheter that is introduced through a vein, and into the heart. Such minimally invasive procedures are generally performed off-pump, which means the heart is beating during the procedure. Such procedures generally require several ports for medical devices to enter the area of the heart and perform the procedures.
Ablation of a precise location within the heart requires precise placement of an ablation device within or near the heart. Precise positioning of the ablation device is especially difficult because of the physiology of the heart, particularly as such recently developed procedures generally occur off-pump. As discussed earlier, in some cases, dissection of tissue is necessary to guide or deliver specialized medical devices to their desired location in the body. In particular, with regard to pulmonary vein antrum isolation, tissue connecting each pair of pulmonary veins to pericardial reflections is often dissected allowing ablation device placement on and/or around the pulmonary veins.
In general, if prior art devices for dissection are used, and if guidance of a specialized medical device to a location after the dissection is desired, separate devices are used for dissection and for placing the specialized medical device. Prior art devices that allow for both dissection and placement of another device, in particular with regard to ablation devices, require suturing a catheter at or near the end of the device while the end of the device is near the heart. Suturing near a beating heart involves risk of negative consequences.
Another challenge to placing ablation devices within or near the heart is that the anatomy of individual patients may differ, requiring different entry points or ports to gain access to the heart. Some current ablation devices include ablating elements connected to rigid elements that are difficult to position within a patient. Manipulation of such rigid elements is problematic and can lead to tissue damage. Also, if a location of an orifice or port does not allow access to a desired part of the heart using such a rigid element, another port must be made in order to reach the desired part.
Ablation devices used for cardiac ablation may have integrated electrodes into jaws of a forceps-like device, which can clamp and ablate tissue between the jaws. Generally the controls for applying ablative energy through the electrodes are located outside the body. Often the controls are located on a generator or switch device that is remote from the handheld portion of the ablation device. Such separate controls may cause the surgeon to direct attention away from the patient. In addition, such separate controls may be out of reach of the surgeon, which means another person may need to manipulate the controls. These issues relating to the proximity of the controls to the surgeon can result in erroneous application of ablative energy at undesired locations in a patient or at undesired times during an ablation procedure. Additionally, with regard to some minimally invasive procedures in particular, such remote controls or switches may be required to be moved around the operating room as the surgeon moves around to access different parts of the body, which is not desired. Even if controls for activating the ablative energy source are located on a handle of the ablation device that is in the hands of the surgeon, during manipulation and placement of the device within a body, the ablative energy controls (e.g., trigger) can be accidentally activated when not desired.
Therefore, there is a need for novel ablation devices, systems for guiding ablation devices into bodies and methods of both using ablation devices and of guiding ablation devices into bodies, which can improve ablation procedures. In particular, the ablation procedures can be improved by decreasing the number of ports necessary to properly access areas of the heart. In addition, ablation procedures may be improved by reducing or eliminating undesired tissue damage such as that caused by using rigid elements to deliver ablating elements. Also, ablation procedures may be improved by avoiding inadvertent application of ablative energy at an undesired location in a body. Further, ablation procedures may be improved by localizing controls to a handle portion that is held by the surgeon.
Some previous ablation devices are described in the following publications, which are herein incorporated by reference in their entireties: U.S. Patent Application Publication No. US 2006/0009759 A1 (Christian et al.); U.S. Patent Application Publication No. US 2006/0036236 A1 (Rothstein et al.); U.S. Patent Application Publication No. US 2006/0020263 A1 (Rothstein et al.); and, U.S. Patent Application Publication No. US 2006/0041254 A1 (Francischelli et al.).
The present invention relates to ablation of tissue during surgical procedures. The present invention is of particular applicability for use during minimally invasive surgical procedures or endoscopic procedures, such as during ablation procedures on a heart (e.g., pulmonary antrum isolation). The device includes a set of clamping jaws with ablating elements, which are connected to a handle assembly by a flexible neck, with controls for opening and closing the clamping jaws and applying ablative energy controlled remotely in the handle. The flexible neck in the device allows the clamping jaws, and ablating elements, to be easily maneuvered and placed in a desired location in a body. The device also preferably includes a lockout mechanism that prevents the ablative energy from being applied unless the clamping jaws, including the ablating elements, are in a closed position. Preferably, the ablative energy cannot be applied unless the user has deactivated the lockout mechanism. The present invention also preferably includes a system used to guide the ablation device to a location in a body where ablation is desired.
The present invention provides advantages over prior art devices and methods for ablating tissue. One advantage is that the flexible nature of the neck allows the ablation device to fit the anatomies of different patients. Another advantage is that using an ablation device with such a flexible neck can reduce the number of ports of entry into a body that need to be made to perform an ablation procedure, because more areas of the heart may be reached by the device using a single port. Yet another advantage of the present invention is, because the clamping jaws may be in a parallel configuration in a closed position and because the neck is flexible, the jaw end of the device may fit easily through small ports used in minimally invasive procedures. A further advantage of the present invention is the flexibility of the neck allows a surgeon to use a variety of approaches to an ablation procedure. An additional advantage is that the clamping jaws are a floating jaw design, which can function with a variety of tissue configurations or thicknesses. A still further advantage is that ablative energy may only be applied when the clamping jaws are in a closed position and the lockout mechanism is deactivated by the user, which avoids applying ablative energy to undesired tissue while maneuvering the device into a body. Further, the controls for the device are conveniently located on the handle, which is being held and controlled by the user. An advantage of the system of the present invention is the option for the ablation device to be able to be rapidly associated and disassociated with a guide wire system to assist in placement of the ablation device.
A first embodiment of the present invention is a device for ablating tissue at a desired location in a body, the device comprising: a pair ofjaws moveable between a spaced apart open position and a closed position, the pair ofjaws comprising at least one ablating element for ablating tissue located between the jaws; a handle comprising controls for remotely controlling the movement of the jaws and the at least one ablative element, wherein the controls for the at least one ablative element comprise a trigger mechanism for applying ablative energy to the at least one ablating element; a neck connecting the jaws and handle; and a lockout mechanism for preventing the trigger mechanism from applying ablative energy when the jaws are in the open position. The trigger mechanism may be positioned on the handle and moveable from a locked position to an unlocked position and in the locked position the trigger mechanism prevents ablative energy from being applied. The lockout mechanism may comprise a lockout flag and the trigger mechanism comprises a trigger, and wherein when the jaws are in the open position, the lockout flag prevents the trigger from being able to activate application of ablative energy. The device may further comprise a lever to move the jaws from the open position to the closed position, the trigger mechanism comprises a trigger, and the lockout mechanism comprises a movable element that is movable between a first position to prevent movement of the trigger and a second position permitting movement of the trigger and an operative connection and the movable element is operatively connected to the lever such that once the lever moves the jaws to the closed position the movable element is moved to the second position.
A second embodiment is a device for ablating tissue at a desired location in a body, the device comprising: a pair of jaws moveable between a spaced apart open position and a closed position, the pair ofjaws comprising at least one ablating element for ablating tissue located between the jaws; a handle comprising controls for remotely controlling the movement of the jaws and the at least one ablative element, wherein the controls for the at least one ablative element comprise a trigger mechanism for applying ablative energy to the at least one ablating element and the controls for the movement of the jaws comprise a lever adapted to close the jaws as the lever is squeezed and to lock when the jaws are in the closed position; a neck connecting the jaws and handle; and a lockout mechanism for preventing the trigger mechanism from applying ablative energy when the jaws are in the open position. Before the lever locks, the lockout mechanism prevents the trigger mechanism from applying ablative energy. After the lever is locked and the jaws are in the closed position, the trigger mechanism may apply ablative energy. The lockout mechanism may comprise a lockout flag and the trigger mechanism may comprise a trigger, and wherein when the jaws are in the open position, the lockout flag may prevent the trigger from being able to activate application of ablative energy. The lockout flag may prevent the trigger from activating ablative energy by preventing pulling of the trigger. The lockout flag may be a visual and tactile indicator that the trigger may not apply ablative energy. When the jaws are in a closed position and locked, the lockout flag may recess into an aperture in the trigger and allows the trigger to activate application of ablative energy.
The present invention will be further explained with reference to the appended Figures, wherein like structure is referred to by like numerals throughout the several views, and wherein:
In the following detailed description of the preferred embodiments, reference is made to the accompanying Figures which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
With reference to the accompanying Figures, wherein like components are labeled with like numerals throughout the several Figures, ablation devices, ablation systems, and methods of use thereof are disclosed, taught and suggested by the multiple embodiments for the purpose of ablation of tissue in a subject body. It is understood that any of the ablation devices, systems and methods, in accordance with the present invention, have applicability for use in any part of a subject's body, including the human body or other animals or creatures, where ablation is useful. The present invention is described below as developed for the application of ablation of cardiac tissue, and in particular for pulmonary vein antrum isolation, in the treatment of atrial fibrillation, as described above in the Background section. However, it is contemplated that the ablation devices, systems and methods may be used for treating any condition for which ablation of tissue is useful.
A device contemplated by the present invention preferably includes basic functionality for ablating tissue in a location in a body. Such a device preferably includes a manner of allowing clamping jaws, and included ablating elements, to be easily maneuvered and placed in a desired location in a body. In addition, such a device preferably includes a manner of preventing ablative energy from being applied unless the clamping jaws, including the ablating elements, are in a closed position and the user has deactivated a mechanism that deactivates an ablative energy source. Also, such a device preferably includes controls that are in close proximity to the user, and more preferably on a handheld portion of the device. Still further, such a device may be part of a system for guiding the device to a location in a body. Such a system preferably includes a manner of attaching, detaching and possibly reattaching at least one guide member to the ablation device in order to assist in guiding the ablation device to a desired location in a body.
With reference initially to
The exemplary embodiment of the ablation device 12 shown in
In order to ablate desired tissue, the tissue is retained or clamped using the jaw assembly 20 of the ablation device 12 prior to ablation.
In order to clamp and release tissue, the jaws 28a, 28b of the jaw assembly 20 preferably move between an open position (as seen in
A purpose of the jaws 28a, 28b being moveable and being able to both close (i.e., approximate) and open is to clamp and release tissue to be ablated, as discussed above. However, another purpose of the approximating jaws 20 is to allow the jaw assembly 20, while in a substantially closed position, to be sized and shaped to be able to pass through a 12 mm or other size of trocar port in a patient during minimally invasive surgery.
The jaw assembly 20 is preferably configured such that the jaws 28a, 28b are able to compensate for a variation in tissue configurations or thicknesses. The design of the jaw assembly 20 is preferably configured so that the jaws 28a, 28b close in an independently floating fashion. In particular, the floating jaw assembly 20 permits tissue of varying thicknesses to be clamped in the jaws 28a, 28b with the jaws 28a, 28b coming into contact with tissue generally along their lengths. For example, thicker tissue can be located closer to the nose 32 than thinner tissue, and the jaws 28a, 28b will not be held open by the thick tissue, but will close and contact tissue along their lengths.
Controls for clamping and ablating tissue are located remotely from the jaws 28a, 28b and are preferably located in the handle assembly 24 that may preferably be handheld.
Referring to
In order to ablate tissue, a fluid assisted elongate electrode assembly is preferably provided in the channel 40a in each housing 38a, 38b. The electrode assembly preferably comprises an elongate tubular electrode 52a, 52b that is retained in the channel 40a and as such are preferably provided within lumens of porous electrode supports 54a, 54b. Preferably, the elongate tubular electrodes 52a, 52b include a series of fluid ports (not seen in Figs.) that are open from an internal fluid passage (not shown) and oriented toward the tissue-contacting side of each jaw 28a, 28b so that a conductive fluid may be dispensed from the electrodes 52a, 52b through the series of fluid ports then migrate laterally through the pores of the porous electrode support 54a, 54b and around its circumference to thoroughly and uniformly wet the porous electrode support 54a, 54b along the right and left jaws 28a, 28b. The conductive fluid (e.g., saline) is preferably provided to each of the electrodes 52a, 52b through separate fluid delivery conduits 36a, 36b (only end portions of the fluid delivery conduits 36a, 36b are shown in
The elongate tubular electrodes 52a, 52b are preferably formed of thin-walled, malleable stainless steel tubing extending between a proximal open end 56a, 56b and a distal, closed end 58a, 58b. The series of fluid ports are formed, e.g., laser drilling, though the sidewall of the tubing from a lumen inside and preferably extend in a single line, although the fluid ports could be formed in any selected array extending around the circumference of the sidewall of the tubing. The electrode supports 54a, 54b preferably comprise a porous polymer such as Porex™ plastic.
The elongate tubular electrodes 52a, 52b are flat electrodes that are preferred because the flat design allows for more energy to be applied to the surface of tissue to be ablated. However, other types and shapes of electrodes or ablating elements are also contemplated by the present invention. Other possible ablating elements are energy transfer elements that transfer energy to target tissue. For example, energy may be conductive elements that may supply RF energy (as shown in FIGS.), HIFU energy, microwave energy, thermal energy, cryogenic energy or ultrasound energy to target tissue. Energy transfer elements may be, for example, laser elements for supplying laser light to target tissue. Two or more energy transfer elements or conductive elements may be arranged in a bipolar arrangement (as shown in FIGS.) wherein at least one element is used as a positive electrode and at least one element is used as a negative electrode. One or more energy transfer elements or conductive elements of the ablation device 12 may be arranged in a monopolar arrangement wherein at least one element is used as one electrode and an indifferent electrode is placed elsewhere on the patient's body such as the back, thigh or shoulder or another site other than the ablation device 12 site.
Energy transfer elements or conductive elements may comprise one or more conductive materials or blends including titanium, titanium alloys, TiNi alloys, shape memory alloys, super elastic alloys, aluminum oxide, platinum, platinum alloys, stainless steels, stainless steel alloys, MP35N, elgiloy, haynes 25, satellite, pyrolytic carbon, silver carbon, conductive metals, conductive polymers or plastics, and/or conductive ceramics. Energy transfer elements or conductive elements may not be conductive but may serve as a conduit to deliver a conductive material such as a conductive fluid. Energy transfer or conductive elements may be porous. For example, energy transfer elements or conductive elements may comprise porous polymers, metals, or ceramics. Energy transfer elements or conductive elements may be coated with non-stick coatings such as PTFE or other types of coatings as discussed herein. In particular, the energy transfer elements may comprise one or more coatings, e.g., hydrophilic coatings. Energy transfer elements or conductive elements may be flexible thereby allowing them to conform to the surface of target tissue. Energy transfer elements or conductive elements may be malleable thereby allowing a surgeon to shape them to conform to the surface of target tissue.
Energy transfer elements or conductive elements may comprise one or more metal conductors such as windings inside a polymer or a conductive mesh material. The energy transfer elements or conductive elements may comprise tubes for delivery of fluids. The tubes may comprise holes or slots. A polymer tube may be placed inside a metal tube to control fluid delivery through energy transfer elements or conductive elements. One or more of the energy transfer elements or conductive elements may be used as one or more nerve stimulation electrodes and/or as one or more cardiac stimulation electrodes. Electrodes may be used for cardiac pacing, defibrillation, cardioversion, sensing, stimulation and/or mapping.
Energy transfer elements or conductive elements may comprise needles designed to penetrate tissues such as fat and muscle. For example, energy transfer elements or conductive elements may be designed to penetrate fat on the heart thereby allowing the energy transfer elements or conductive elements to reach cardiac tissue. The needles may allow fluids such as conductive fluids, chemicals such as ablation chemicals, drugs, biological agents and/or cells to pass through. The needles may allow a vacuum or suction to pass through.
In additional embodiments, the ablation device 12 of the present invention may include means for tracking the position of the ablation device 12. The means for tracking the position of the ablation device 12 may include, for example, sensors and imaging devices. An example of a disclosure of such a tracking means is described in U.S. Patent Application Publication US 2006/0229594 A1 (Francischelli et al.), and is herein incorporated by reference in its entirety.
Adhesive may be applied to maintain the elongate tubular electrodes 52a, 52b and porous electrode supports 54a, 54b in the channels 40a in the jaw housings 38a, 38b. The adhesive used may not block migration of conductive fluid around the porous electrode supports 54a, 54b.
In order to supply energy or power to the elongate tubular electrodes 52a, 52b, power source wires 34, in the preferred embodiment, extend distally from a power source (preferably separate from ablation device 12) through the neck 22 and are soldered to the elongate tubular electrodes 52a, 52b, for example, as shown in
Other methods of irrigating the electrodes or ablating elements, besides that method described above, are also contemplated by the present invention. The purpose of irrigation of the electrodes with saline or other conductive fluid is to help decrease the interface impedance, cool the tissue, and allow for a greater lesion depth. Irrigation can also help prevent tissue or fat from clogging the electrodes and help keep the electrodes clean.
In order to close the jaws 28a, 28b while in an open position, the pull wire 35 is pulled from the proximal portion of the device 12 (how this is performed is discussed in more detail below with regard to the handle portion 24), which results in the clevis 64 moving proximally within a formed interior cavity of the nose 32. As the clevis 64 is pulled proximally, it exerts force on the jaw arms 42a, 42b, which are connected to the clevis 64 by the pins 50a, 50b. As the jaw arms 42a, 42b are pulled proximally for an initial distance within the nose 32, the slots 48a, 48b slide along the pins 60a, 60b in the nose 32, which moves the jaws 28a, 28b toward each other in a scissor-like motion with the pins 60a, 60b located at an intermediate point within the slots 48a, 48b. At that point, the jaws 28a, 28b are preferably substantially parallel as controlled by the shape of the slots 48a, 48b and interaction with the pins 60a, 60b. Once the jaws 28a, 28b are substantially parallel (but not yet closed), further pulling proximally on the clevis 64 pulls the jaws 28a, 28b further proximally as well. The pins 50a, 50b are extending through the slots 62a, 62b in the clevis 64 are guided through the slots 51a, 51b in the nose halves 32a, 32b. The shape of slots 51a, 51b force the pins 50a, 50b and thus the jaws 28a, 28b to move toward each other as the pull wire 35 is further moved proximally relative to the neck 22 and nose 32. At the same time, the width of slots 62a, 62b of the clevis 64 permit inward movement of pins 50a, 50b. Also, pins 60a, 60b slide along slots 48a, 48b. The combination of interactions between pins 50a, 50b and 60a, 60b, and slots 48a, 48b and 51a, 51b results in the jaws 28a, 28b moving toward each other in a substantially parallel position until the jaws 28a, 28b are in a substantially closed position (contacting each other). The slots 51a, 51b also limit how far the clevis 64 may move proximally in the nose 32. This arrangement of pins and slots also permits the jaws 28a, 28b to float to the degree permitted by the interaction of the pins and slots so that the jaws 28a, 29b can adjust in orientation relative to one another based upon counter-pressure applied to the jaws surfaces from the engagement with tissue.
The pull wire 35 extends from the handle 24 portion through the neck 22 and into the jaw assembly 20 through a lumen in the distal neck retainer barb 66.
In order to return the jaws 28a, 28b from a closed position to an open position, the jaw assembly 20 includes ajaw return spring 74 (see
The pull wire 35 extends proximally in the device 12 from the jaw assembly 20, through the neck 22 and into the handle 24. As the pull wire 35 enters the handle 24, the pull wire 35 is fed through a proximal neck retainer barb 80 (shown on
The pull wire 35 is preferably made of stainless steel, although other suitable materials may be used, with a solid wound coil surrounding the pull wire 35. The preferred configuration of the pull wire 35 and surrounding coil is an incompressible coil. Other suitable materials and/or designs that act as an incompressible coil are also contemplated by the present invention. A purpose of the incompressible coil configuration is to maintain the overall length of the pull wire 35 when the portion of the pull wire 35 that extends through the flexible neck 22 is flexed or twisted etc.
The jaw assembly 20 is functionally connected to the handle assembly 24 by the neck 22. A purpose of the neck 22 is to provide a shaft or lumen through which components (e.g., power source wires 34, fluid delivery conduits 36 and pull wire 35) may extend between the jaw assembly 24 and the handle assembly 24. The length of the neck 22 then is preferably related to the distance required in a procedure to allow the jaw assembly 20 to be at an desired anatomical location with the handle assembly 24 being outside the body (i.e., ex vivo).
The neck 22, which attaches the jaw assembly 20 to the handle 24, is preferably flexible or “floppy” in nature. In one embodiment, the neck 22 may be flexible or floppy like a rope, for example. The flexible or “floppy” nature may thereby allow a guide member or device to be used to easily position the jaw assembly 20 of the ablation device 12 into a position to ablate tissue. The flexible nature of the neck 22 enables the ablation device 12 to be used with many different anatomies found in different patients. The neck 22 may be capable of effectively transmitting torque.
Preferably, the neck 22 is made of extruded polyurethane with a 304 stainless steel braid. However, other suitable components or designs that provide the desired flexibility of the neck 22 are also contemplated by the present invention.
In order to control approximation of the jaws 28a, 28b and application of ablative energy, which both take place at or near the jaw assembly 20 of the ablation device 12 preferably when the jaw assembly 20 is placed at a desired location in a body, the controls for approximation and ablation are preferably located ex vivo. Preferably, the controls are located in and/or on the handle assembly 24, which remains ex vivo during an ablation procedure. Preferably, the handle assembly 24 comprises a handle casing 86 having two mating handle casing halves (one half of which is shown in
As discussed previously, in order to cause the components of the jaw assembly 20 to close the jaws 28a, 28b, the pull wire 35 is pulled proximally using controls in the handle assembly 24. Referring to
In the preferred embodiment shown in the figures, and in
In general, a basic purpose of the clutch assembly 94 is to translate the motion of the jaw activation lever 122, both toward and away from the handle casing 86, into generally proximal and distal, respectively, motion of the link arm 92. The link arm 92, in turn, moves the pull wire 35 proximally or distally, which closes or opens the jaws 28a, 28b, respectively.
The clutch assembly 94, as shown in
More particularly, with regard to the components of the clutch assembly 94, in order to close the jaws 28a, 28b, the pull wire 35 is pulled proximally as the wire terminal 82 is pulled proximally in the recesses (one of which is 89a) by the link arm 92. The purpose of allowing the rollers 88 and attached wire terminal 82 to rotate in the recesses (one of which is 89a), while the link arm 92 of the clutch assembly 94 moves generally proximally, is to prevent bending the pull wire 35 in the handle assembly 24, which could in turn cause tension and fracture the pull wire 35 as it extends out through the neck 22 and into the jaw assembly 20.
In particular,
The clutch spring 106 tension may be adjusted by tightening or loosening the screw 112 and anchor 114. In particular, in the embodiment shown in the figures, tightening the screw 112 will wind the clutch spring 106 tighter.
Referring to
In order to activate, or close the jaws 28a, 28b, the lever 122 is squeezed or otherwise moved toward the handle casing 86. Moving the lever 122 in such a way results in the extension portion 136 of the lever 122 moving into the handle casing 86, which in turn pivots the cam 104 counter-clockwise (as in
With the jaws 28a, 28b in a closed position, the components of the handle assembly 24 generally resemble
The jaw closure mechanism described above is one exemplary such mechanism. It is also contemplated by the present invention that the jaws 28a, 28b may be driven by either a mechanical mechanism, e.g., a drive cable or wire in a compression jacket, a hydraulic mechanism, e.g., a piston powered by fluid pressure, and/or an electrical mechanism, e.g., a servo motor. Each of the jaw closure mechanisms described above would allow neck 22 to remain flexible or floppy when the jaws 28a, 28b were either in an open position and/or a closed position.
In the present invention, preferably the ablation device 12 includes a mechanism for preventing inadvertent application of ablative energy, which is referred to as a lockout mechanism or feature. In order to avoid inadvertent ablation, the lockout mechanism is preferably incorporated into the handle assembly 24. An example of such a lockout mechanism is included in the embodiments shown in
Before the jaws 28a, 28b are locked in a closed position, some components of the handle assembly 24, in the exemplary device 12, prevent ablative energy from being applied. In particular, the exemplary embodiment prevents ablative energy from being applied by preventing a trigger 140 on the device 12 from being pulled. The mechanism for preventing the trigger 140 from being pulled to apply ablative energy may be referred to as a lockout mechanism. In the lockout mechanism illustrated, there is preferably a visual and/or tactile lockout flag 142 on or near the trigger 140 that indicates when the lockout mechanism is engaged or activated. While the lockout mechanism is activated, the lockout flag 142 extends through an aperture in the trigger 140 and can be seen and felt on the trigger 140, and when deactivated the lockout flag is recessed in the aperture in the trigger 140.
Additional components of the exemplary lockout mechanism can be seen separately in
The power trigger subassembly is incorporated into the remainder of the handle assembly 24 as seen in
In order to move the slider 150 proximally to cause deactivation of the lockout mechanism, referring to
When the lockout flag 142 is recessed enough in order for the trigger 140 to be depressed, the lever 122 is also locked into the handle casing (one half of which is 86a). In the exemplary embodiment shown, a pawl 158 is attached to the handle casing (one half of which is 86a) and extends through slot 151 in the slider 150. The pawl 158 also has a tension spring 160 attached proximally. The lever 122 may be locked in the squeezed position when as the extension 136 is moving into the handle casing (one half of which is 86a) the pawl 158 catches on a projection 196 in the extension 136, which can be seen in the cross section of
In order to release the jaw activation lever 122, open the jaws 28a, 28b on the jaw assembly 20, and reactivate the lockout mechanism, a lever release button 192 (
The lockout mechanism illustrated in the figures and described above is one example of such a mechanism that prevents ablating energy from being inadvertently applied at an undesired location in a body. Other lockout mechanisms that prevent such inadvertent or accidental application of ablating energy at an undesired location in a body are also contemplated by the present invention. For example, it is contemplated that a lockout mechanism may be controlled through feedback from any number of sensors on the device, and in particular on the jaws of the device. Such sensors, could for example, sense whether or not they are clamped on desired tissue, which could in turn deactivate the lockout mechanism and allow ablative energy to be turned off and on. Any suitable feedback mechanisms are contemplated by the present invention for use in a lockout mechanism.
In order to supply power and fluid to the fluid assisted elongate electrode assembly that is preferably part of the ablation device 12, power source wires 34 and fluid delivery conduits 36 need to extend from a power source and a fluid source through the handle assembly 24, neck 22 and into the jaw assembly 20. There is discussion above of the preferred route for the power source wires 34 and fluid delivery conduits 36 through the neck 22 and jaw assembly 20. In the handle assembly 24, a preferred route of the power source wires 34 and fluid delivery conduits 36 is illustrated in
The power source and fluid source are preferably located remotely from the ablation device 12. As seen in
The ablation device 12 may incorporate one or more switches to facilitate regulation of one or more components or features of ablation device 12 by the operator. For example, one or more switches may control the supply of irrigation fluid and/or ablation energy to the jaw assembly 20 of ablation device 12. The one or more switches may be, for example, a hand switch, a foot switch and/or a voice-activated switch comprising voice-recognition technologies. The one or more switches may be incorporated on and/or in handle 24 of ablation device 12.
In the preferred embodiment shown in the figures, a power source switch 164 (e.g., RF switch) is included in the handle assembly 24 (
Although not illustrated in the figures, the ablation device 12 may include one or more sensors or sensing elements to monitor one or more components or features. For example, preferably, the ablation device 12 may have the capability to monitor transmurality of ablation lesions. An example of a preferred algorithm used to monitor transmurality is disclosed in co-pending Provisional Patent Application, having Ser. No. 60/832,242, and is incorporated herein by reference in its entirety.
The ablation device 12 described above may, preferably, be part of a system 10 (
As part of a system 10 for guiding the ablation device 12 to a desired location in a body, the ablation device may include different jaw assemblies 20 for attachment to the neck 22 of the device 12. In particular, different jaw assemblies 20 that may be provided in such a system 10 may have jaws 28a, 28b with different curvatures or shapes. A purpose of having such different jaw assemblies is to accommodate different ablation procedures at different anatomical locations, as well as to accommodate the differing anatomy of individual patients.
The ablation device 12 and/or system 10 may be used in ablation procedures in various areas in a body where ablation of tissue is desired. In particular, the ablation device 12 and system 10 is suitable for use in pulmonary antrum isolation. As described above there are different surgical approaches to pulmonary antrum isolation. With reference to
The guide members 14, 16 or device may comprise a length of single or multi-lumen tubing, for example. An active guide connection may be included which has a connector member or device 216, e.g., a ball-in socket fitting, a lure fitting and/or a suture, located at one or more ends of the guide members 14, 16, for connection between the distal end portion of an ablation device (shroud 30). The guide members 14, 16 may include reference markings, to provide, for example, depth or length references. The guide member 14 or 16 may comprise two or more lengths of tubing, and the separate tubing sections may be color coded to facilitate differentiation between each other. In one embodiment, the guide member 14 or 16 may be used to safely pull the jaws 28a, 28b of the ablation device 12 into place if the neck 22 of the ablation device 12 is loose or floppy, e.g., the user cannot actively push or poke the jaws 28a, 28b into tissue, thereby causing undesirable tissue damage. The guide member 14 or 16 may include one or more blunt ends. The guide member 14 or 16 may include a suture on its distal end.
In order to attach the first and second guide members 14, 16 to the distal ends of the jaws 28a, 28b of the ablation device 12, an attachment means, such as that illustrated in
The steps for ablating the right two pulmonary veins are then repeated on the right side of pulmonary ostium 176 (in
The ablation system 10 and its components are preferably made of biocompatible materials such as stainless steel, biocompatible epoxy or biocompatible plastic. Preferably, a biocompatible material prompts little allergenic response from the patient's body and is resistant to corrosion from being placed within the patient's body. Furthermore the biocompatible material preferably does not cause any additional stress to the patient's body, for example, it does not scrape detrimentally against any element within the surgical cavity.
It will be appreciated by those skilled in the art that while the invention has been described above in connection with particular embodiments and examples, the invention is not necessarily so limited, and that numerous other embodiments, examples, uses, modifications and departures from the embodiments, examples and uses are intended to be encompassed by the claims attached hereto. The entire disclosure of each patent and publication cited herein is incorporated by reference, as if each such patent or publication were individually incorporated by reference herein.
This application claims the benefit of U.S. Provisional Application having Ser. No. 60/762,699, filed Jan. 27, 2006, entitled “ABLATION DEVICE AND METHOD,” which application is incorporated herein by reference in its entirety. This application also incorporates by reference in their entirety the following co-pending U.S. Patent Applications: application having Ser. No. ______, filed on the same day as the present application, entitled “ABLATION DEVICE AND SYSTEM FOR GUIDING ABLATION DEVICE INTO BODY” and having Attorney Docket No. MTI0050/US (P-24242.01); and, application having Ser. No. ______, filed on the same day as the present application, entitled “METHODS OF USING ABLATION DEVICE AND OF GUIDING ABLATION DEVICE INTO BODY” and having Attorney Docket No. MT10053/US (P-24242.02).
| Number | Date | Country | |
|---|---|---|---|
| 60762699 | Jan 2006 | US |
