1. Technical Field
This invention relates to a device and method for positioning an implanted elongated structure, such as an implanted electrical cardiac lead, to facilitate removal, or extraction, of the implanted elongated structure from the body of a patient.
2. Background Information
A variety of medical treatments and surgical methods entail implanting an elongated structure in the body of a human or veterinary patient. Examples of such elongated structures include catheters, sheaths, and cardiac electrical leads (such as pacemaker leads and defibrillator leads), as well as a variety of other devices. Over time, it can become necessary or desirable to remove the implanted elongated structure from the body of the patient. However, if the elongated structure has been implanted for an extended period of time, encapsulating biological tissue can grow around the elongated structure, making it difficult to remove the structure from the encapsulating tissue.
A heart pacemaker is typically implanted in a subcutaneous tissue pocket in the chest wall of a patient. A pacemaker lead extends from the pacemaker through a vein into a chamber of the patient's heart. The pacemaker lead commonly includes a conductor, such as an electrical wire coil, for conducting electrical signals (such as stimulating and/or sensing signals) between the pacemaker and the heart. Leads for defibrillators are generally similar to pacemaker leads, and are positioned about the heart. Defibrillator leads may be affixed either internally or externally of the heart.
While cardiac electrical leads typically have a useful life of many years, over time such leads may become encapsulated by fibrotic tissue against the heart itself or the wall of the vein, or against other surrounding tissue. Encapsulation is especially encountered in areas where the velocity of the flow of blood is low. The fibrotic tissue can be very tough, which makes it difficult to remove the lead from the area of the heart without causing trauma to the area. When small diameter veins through which a pacemaker lead passes become occluded with fibrotic tissue, separation of the lead from the vein can cause significant damage to the vein, including the possible dissection or perforation of the vein. In such cases, separation of the lead from the vein is usually not possible without restricting or constraining movement of the lead, i.e., fixing the lead in position with respect to the patient, and in particular, with respect to the patient's vein.
To avoid this and other possible complications, some useless pacemaker or other leads are simply left in the patient when the pacemaker or defibrillator is removed or replaced. However, such a practice can incur the risk of an undetected lead thrombosis, which can result in stroke, heart attack, or pulmonary embolism. Such a practice can also impair heart function, as plural leads can restrict the heart valves through which they pass.
There are many other reasons why removal of a useless lead may be desirable. For example, if there are too many leads positioned in a vein, the vein can be obstructed to the extent that fluid flow through the vein is severely compromised. In addition, multiple leads can be incompatible with one another, thereby interfering with the pacing or defibrillating function. An inoperative lead can migrate during introduction of an adjacent second lead, and mechanically induce ventricular arrhythmia. Other potentially life-threatening complications can require the removal of the lead as well. For example, removal of an infected pacemaker lead may be desirable so as to avoid conditions such as septicemia or endocarditis.
Surgical removal of a heart lead in such circumstances may involve open heart surgery. However, open heart surgery is accompanied by significant risk and cost to the patient, as well as a potential for unintended complications. A variety of methods and apparatuses have been devised as alternatives to open heart surgery for heart lead removal. Several of these methods and apparatuses are described in related patents, such as U.S. Pat. No. 5,697,936, titled “Device for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 5,507,751, titled “Locally Flexible Dilator Sheath”; U.S. Pat. No. 5,632,749, titled “Apparatus for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 5,207,683, titled “Apparatus for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 4,943,289, titled “Apparatus for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 5,011,482, titled “Apparatus for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 5,013,310, titled “Method and Apparatus for Removing an Implanted Pacemaker Lead”; U.S. Pat. No. 4,988,347, titled “Method and Apparatus for Separating a Coiled Structure from Biological Tissue”; U.S. Pat. No. 5,423,806, titled “Laser Extractor for an Implanted Object”; U.S. Pat. No. 6,419,974, titled “Radio Frequency Dilator Sheath”, and U.S. Pat. Nos. 6,687,548 and 6,712,826, each titled “Apparatus for Removing an Elongated Structure Implanted in Biological Tissue”, among others. Each of the aforementioned patents is incorporated by, reference as if fully set forth herein.
Most of the aforementioned patents describe manual, or mechanical, devices that are used for removing an implanted structure, such as a pacemaker lead. Others describe non-mechanical techniques, such as laser extraction and radio frequency extraction. The non-mechanical techniques have been effective in cases when the amount and/or placement of fibrous growth that surrounds the implanted lead renders manual extraction difficult or impossible. One example of an effective device that uses radio frequency extraction to enable the physician to cut away the heavy growth is the PERFECTA® electrosurgical dissection sheath, available from Cook Vascular Incorporated, of Leechburg, Pa. The PERFECTA® sheath utilizes an intermittent discrete RF dissecting arc between bipolar electrodes located at the sheath's distal end. This sheath enables the physician to separate, with directed precision, a transvenous lead from its fibrous binding attachments.
Although the prior art devices have been found to be reasonably effective in many situations, physicians continue to encounter particularly difficult situations in which existing extraction devices provide unsatisfactory or inconsistent results. Due to the multiplicity of factors that may contribute to the difficulty in extracting an implanted lead, a technique that may be effective in one instance, may not provide similarly successful results in another instance. For example, manual devices normally are provided with single or telescoping flexible sheaths. Such sheaths, generally formed from a polymer, are intended to have the flexibility to enable the sheath to traverse pathways in the vessel. However, such sheaths may lack sufficient strength to cut through particularly tough tissue growth and calcification around the implanted lead. They may also have difficulty traversing particularly tortuous pathways in the vessel. Laser and radio frequency employ energy to cut through fibrous growths. However, some growths may be too stubborn for even these energized sheaths. In addition, these sheaths may lack the flexibility to maneuver tortuous pathways.
In some instances, it is necessary to traverse a fairly tight curve in an artery or vein when tracking a lead intended for removal. One example is the curve in the subclavian vein. At times, removal along such a curve can be accomplished by maintaining good tension on the lead, e.g. with the help of a locking stylet well anchored to the distal end of the lead. This is intended to force the sheath to bend and thus negotiate the curve, without putting undue force upon the vein wall on the outside of the curve.
At other times, however, it can be difficult to negotiate the curved pathways with a lead removal device. In these and other instances, it would be desirable to have the ability to reposition the proximal end of the lead by directing the lead end away from the vessel having the tight curve, and into another vessel or pathway in a manner such that a less curved pathway is navigated when removing the lead. Thus, for example, when attempting to negotiate the curvature along the subclavian vein, it would be desirable to reposition the proximal end of the lead by redirecting it into the superior vena cava. In this case, a fairly straight pathway for lead removal may be achieved through the internal jugular vein.
In one embodiment, a device is described herein for adjusting a position of an elongated structure implanted in biological tissue to facilitate removal thereof. An outer sleeve and an inner sleeve each have a proximal end and a distal end. The inner sleeve is received in the outer sleeve and movable relative thereto. A manipulator mechanism is engaged with the inner sleeve distal end, and extends in a distal direction therefrom. The manipulator mechanism is structured and arranged for capture of the elongated structure, and for locking the elongated structure to the device upon relative movement of the inner and outer sleeves. A handle is engaged with the inner sleeve proximal end, and a plunger is engaged with the outer sleeve proximal end. The plunger is engaged with the handle and movable relative thereto. The plunger and handle are aligned such that upon relative movement therebetween, the outer sleeve advances distally relative to the inner sleeve in a manner such that the manipulator mechanism is maneuverable to capture the implanted elongated structure, whereby the position of the elongated structure may be controllably adjusted to facilitate removal thereof from the biological tissue.
In another form, a method is described for adjusting a position of an elongated structure implanted in biological tissue to facilitate removal thereof, wherein at least a portion of the elongated structure extends along a generally curved body pathway. A device comprising a sleeve member having a proximal end and a distal end, and a manipulator mechanism engaged with the sleeve member distal end and extendable in a distal direction therefrom is positioned for insertion along a substantially non-curved body pathway, wherein the manipulator mechanism is structured and arranged for capture of the elongated structure. A distal end of the device is inserted along the substantially non-curved body pathway, and the device is advanced along the substantially non-curved pathway until the device distal end approaches a length of the implanted elongated structure. The manipulator mechanism is maneuvered in a manner to capture the implanted elongated structure. The implanted elongated structure is locked onto the device, and the device having the elongated structure locked thereon is further advanced along the substantially non-curved pathway until the implanted elongated structure is at least substantially in the substantially non-curved pathway.
In yet another form, a device is described for adjusting a position of an implanted elongated structure implanted in biological tissue of a patient to facilitate removal thereof. An elongated shaft member has a proximal end and a distal end. A manipulator mechanism is engaged with the shaft member distal end and extendable in a distal direction therefrom. The manipulator mechanism is selectively maneuverable between a capture position wherein the implanted elongated structure is movably captured by the manipulator mechanism, and a locked position wherein movement of the implanted structure relative to the manipulator mechanism is at least substantially prevented. A control mechanism is engaged with the shaft member for controlling the maneuverability of the manipulator mechanism.
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It should nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
The present invention relates to a device for use in adjusting a position of an elongated structure that has previously been implanted in a patient, to facilitate removal of the elongated structure. In the following discussion, the terms “proximal” and “distal” will be used to describe the opposing axial ends of the device, as well as the axial ends of various component features of the device. The term “proximal” is used in its conventional sense to refer to the end of the device (or component thereof) that is closest to the operator during use of the device. The term “distal” is used in its conventional sense to refer to the end of the device (or component) that is at the greatest distance from the operator, or that is initially inserted into the patient.
The implanted structure targeted for positioning may comprise a cardiac lead. A cardiac lead, as the term is used herein, refers to a lead that is used in connection with a heart-related device. Non-limiting examples of cardiac leads that may be positioned by the inventive device include pacemaker leads, defibrillator leads, coronary sinus leads, and left ventricular pacing leads. When the device is used to position a cardiac pacemaker lead, the distal end of the cardiac lead will normally be located within the vascular system of the patient, and in particular, within a chamber of the patient's heart (such as in an atrium or ventricle of the heart). When the implanted elongated structure is a defibrillator lead, the distal end of the lead may be located either in or about the heart of the patient. The distal ends of other types of implanted elongated structures targeted for positioning may not necessarily be near the heart.
In addition to cardiac leads, the invention may also be used to position other devices or leads, such as neurological pacing and stimulation leads. A non-limiting list of still other structures that can be positioned by the inventive device includes implanted catheters, sheaths, cannulae and the like. For convenience, the following discussion will refer to the positioning of a cardiac lead, such as a pacemaker or a defibrillator lead, to facilitate removal of the lead from the body of a patient. However it should be understood that this is no way intended to be a limitation on the scope of the invention, and that the device may be suitable for positioning other implanted structures, such as the elongated structures referred to above.
When the inventive device is used for positioning a proximal end of a cardiac lead in order to facilitate eventual removal, or extraction, of the lead, those skilled in the art will appreciate that the proximal end of the lead should initially be severed from the control device, e.g., a pacemaker or a defibrillator, prior to any attempts to adjust the position of this severed lead end, for facilitating removal of the lead. Typically, the more distal portion of the lead will be implanted, and may be at least partially encapsulated by fibrotic tissue.
Generally speaking, the device for adjusting a position of an implanted elongated structure includes an elongated shaft mechanism, and a manipulator mechanism extendable from a distal end of the shaft mechanism. Preferably, the manipulator mechanism comprises a pair of controllable manipulator arms. A control mechanism enables the arms to be selectively manipulable between an “at rest”, or free, position; a semi-locked, or “capture” position wherein the arms generally encircle or enclose the implanted structure but do not prevent movement of the arms or implanted structure relative to one another; and a locked position wherein the implanted structure is essentially locked into a fixed position relative to the arms, and further movement of the implanted structure relative to the arms is at least substantially prevented.
In the embodiment shown in
In a preferred embodiment, manipulator mechanism 80 comprises a generally cylindrical base member 82 having manipulator arms 84, 86 extending in a distal direction therefrom. Preferably, manipulator arms 84, 86, comprise individual wire members that terminate in respective loops 85, 87, as shown. In one preferred embodiment, loops 85, 87 are filled with a material, such as solder. Filling the loops with a filler material as described provides increased visibility and tracking of the manipulator arms. In addition, the presence of a filler material ensures that the cardiac lead or other structure being positioned does not inadvertently become entangled or otherwise trapped within the loop. This structure also creates a less aggressive platform for the lead to be locked against, thus helping to prevent potential damage to a lead when in the locked position.
In the embodiment shown, handle 12 comprises first handle half 18 and second handle half 20. Plunger 30 comprises first plunger half 36 and second plunger half 38. Those skilled in the art will appreciate that handle 12 and plunger 30 need not necessarily be composed of first and second halves as shown, and that the handle and/or plunger may comprise more, or fewer, components.
Plunger halves 36, 38 are shown in a disengaged condition in
Plunger 30 further includes an indent 46 proximal of channel 40. Indent 46 extends transversely through the proximal length of plunger 30, and is sized to receive ball 59 of ball plunger 58, as described herein. Preferably, plunger 30 also includes a knob 49 or like structure at its proximal end to facilitating grasping and control of the plunger during use of device 10. When present, knob 49 may be formed in any shape to facilitate grasping by the operator of the device.
Handle halves 18, 20, are shown in a disengaged condition in
Handle halves 18, 20 also include respective longitudinal grooves 19, 21 along an internal surface thereof. Grooves 19, 21 are sized and arranged such that when handle halves 18, 20 are engaged to form handle 12, a longitudinal passageway is defined through the axial center of handle 12. As shown in
One of handle halves 18, 20 is fitted with a detent mechanism at the large diameter portion thereof. Detent mechanisms are known in the art as having the capacity to temporarily, or permanently, restrict, pause, or otherwise arrest movement of a first (movable) article with reference to a second (fixed) article. In the preferred embodiment shown, the detent mechanism comprises a ball plunger 58 (
Ball plunger 58 is sized and arranged such that the closed end of the ball plunger is received (e.g., by a press fit) into a corresponding hole 29 (
As best shown in
Drive collar larger diameter proximal portion 42 includes an aperture 45 extending transversely therethrough. A capture pin 28 is received in aperture 45. As best shown in FIGS. 3 and 6-9, capture pin 28 is sized and arranged such that its respective axial ends are received in the extended diameter distal segment defined by extended diameter portions 22 of the handle halves 18, 20 as described above. The respective ends of capture pin 28 are thus positioned to ride along the length of plunger channel 40 during relative movement between handle 12 and plunger 30, as described herein. As best shown in
Those skilled in the art will appreciate that the components described herein can be formed from conventional materials known to have the strength and stability for the respective purposes described. Thus, for example, the handle 12 and plunger 30 can be formed from a high strength polymeric material, such as the acetal resin DELRIN®. The drive collar, capture pin, outer sleeve, inner sleeve, and ball plunger can be formed from metal or metal alloys, such as stainless steel.
The manipulator mechanism cylinder, and manipulator arms, can also be formed from metal or metal alloys, such as stainless steel. The manipulator arms are structured such that they are capable of controllably encircling and manipulating the lead. The various bends and angles to which the manipulator arms may be adjusted to enable capture of a lead give the manipulator arms an ability to reach and maneuver the lead, as described below. When the manipulator arms include filled terminal loops 85, 87 as described above, the loops protect against entanglement of wires or lead coils within the loops, and also minimize the possibility of vessel wall damage. Preferably, the loops are filled in a manner that generally defines a dome. The bends, domed loops, and/or angles as specified enhance the ability of the device to safely manipulate and capture the lead, and to controllably maintain capture while maneuvering along the lead.
The inner and outer sleeves described herein may be formed from conventional biocompatible materials known for such purposes in the medical arts. As with the components described above, the inner and outer sleeves may also be formed of metals and metal alloys, such as stainless steel. Alternatively, the inner and outer sleeves may be formed from polymeric materials such polypropylene, polyurethane, polyethylene, nylon, PTFE, and the like. If desired, the sleeves can be reinforced along their length, or a segment of their length, with conventional reinforcing materials, such as a coil or a braid. Such reinforcements are well known in the medical arts, and are typically formed from a metal or metal alloy. If desired, selected portions of one or both of the sleeves, such as the distal tip portion, can be provided with means for x-ray or fluoroscopic vision. Such means are well known in the art, and may include, for example, the incorporation of a radiopaque band, or the inclusion of radiopaque particles in the selected portion. As still another alternative, a polymeric sleeve can be provided with a tip formed of a metal or metallic alloy to provide such visibility. Increased visibility of the tip may be beneficial because it allows the operator to determine the location of the tip at a particular point in time, and also provides the operator with the ability to track the position and orientation of the tip with reference to the lead body.
The respective dimensions of the components may be varied for a particular application of the positioning device. For example, in one non-limiting embodiment for use in positioning a cardiac lead as described, the handle may have dimensions of 3 in. [7.62 cm] lg.×0.75 in. [1.9 cm] OD (2 in. OD [5.1 cm] at proximal end). The plunger may have dimensions of 6.5 in. [16.5 cm] lg.×0.5 in. [1.27 cm] OD (1.5 in. [3.81 cm] OD at proximal end). The drive collar may have dimensions of 0.5 in. [1.3 cm] lg.×0.085 in. [0.22 cm] OD (smaller diameter portion of drive collar) and 0.25 in. [0.635 mm] OD (larger diameter portion of drive collar). The capture pin may have dimensions of 0.625 in. [1.59 cm] lg.×0.125 in. [0.32 cm] OD. The outer sleeve may have dimensions of 12 in. [30.5 cm] lg.×0.134 in. [0.34 cm] OD×0.114 in. [0.29 cm] ID. The inner sleeve may have dimensions of 12 in. [30.5 cm] lg.×0.109 in. [0.28 cm] OD×0.085 in. [0.22 cm] ID. The manipulator arms may have dimensions of 0.025 in. [0.064 cm] OD×2 in. [5.1 cm] lg.×0.75 in. [1.9 cm] width.
Those skilled in the art will appreciate that these dimensions are only intended to represent the dimensions for one particular embodiment, and that the dimensions of any or all of the respective components may be varied as desired for a particular application. The components may be formed by well-known techniques, such as molding (e.g., handle and plunger), machining (e.g., drive collar and capture pin), welding and drawing (e.g., outer and inner sleeves), and wire forming (e.g., manipulator arms).
Operation of positioning device 10 will now be described, with primary reference being made to
In order to manipulate arms 84, 86, in a manner such that a cardiac lead can be captured between the arms, plunger 30 is moved in the distal direction relative to handle 12, as shown in
In the view of
As a consequence of this distal movement of plunger 30, outer sleeve 50 has been further advanced distally over manipulator arms 84, 86, when compared to the position of
Plunger 30 is then further urged in the distal direction to overcome the resistance resulting from the capture of ball 59 in indent 46. Once this resistance is overcome, plunger 30 is further advanced until capture pin 28 abuts the proximal end of channel 40. This fully engaged capture position is shown in
Those skilled in the art will appreciate that activation of the manipulator arms need not necessarily result from relative movement of outer and inner sleeves utilizing a plunger and handle as described. Other mechanisms for activating the manipulator arms may be substituted. For example, instead of utilizing an indent as a means of gauging position, a slotted rod mechanism with, e.g., a spring loaded button actuator may be substituted. This approach allows for automatic locking and manual unlocking from one position to another, to ensure that the device remained in the desired position until purposely unlocked by the user. A screw type mechanism could also be used to gauge and control position.
One example describing the use of positioning device 10 to re-position an implanted structure, such as cardiac lead L, to facilitate removal of the lead from the body of a patient will now be provided. This example is illustrated in
In this example, a cardiac lead L extends from the implanted pacemaker or defibrillator along a curved pathway that extends through the subclavian vein (SV), the innominate (brachiocephalic) vein (IV), and into the superior vena cava (SVC). The distal lead end (DLE) is affixed in the heart. This arrangement is shown in
At times, however, it can be difficult to track over the lead along curves such as this with a conventional lead removal tool, if possible at all. Therefore, positioning device 10 may be utilized to adjust the position of lead L, in a manner that the lead is repositioned to a less curved pathway to facilitate removal of the lead. As shown in
Device 10 is advanced through the work station sheath 90 along the internal jugular vein until the distal end of device 10 reaches a length of lead L. Device 10 is then maneuvered into position to capture the severed lead, as shown, e.g., in
Device 10, and lead L locked onto device 10, are further advanced downwardly into the superior vena cava (SVC), preferably until severed lead end SLE has completely passed, or substantially completely passed, through the subclavian vein and the curve of the innominate vein (IV), and into the superior vena cava. This is indicated by the direction of the arrows in
Device 10 and lead L are withdrawn to the extent possible through the relatively straight pathway of the internal jugular vein (IJV), as shown by the arrows in
Following re-positioning, and any possible withdrawal, of the severed lead end SLE by device 10 as described, device 10 may be disengaged from lead L by reversing the steps described above with reference to
By utilizing device 10, the position of lead L has been adjusted in a manner such that the lead removal tool need not track the lead along a curved pathway, such as the curved pathway defined by the innominate vein and the superior vena cava. Rather, the lead removal tool tracks the lead over a fairly straight pathway defined by the internal jugular vein, as described and shown, e.g., in
Although positioning device 10 has been primarily described herein with regard to one possible use, i.e., for adjusting a position of a cardiac lead L implanted in a particular curved pathway to facilitate removal of the lead, those skilled in the art will appreciate that use of device 10 is not restricted to the specific use described in the examples. Rather, the device may be utilized in other instances in which it is desired to remove a structure implanted in biological tissue, and in which it would otherwise be necessary to track a removal tool along a severely curved, somewhat curved, or even a noncurved, pathway. The nature of the device with regard to its ability to capture, hold, push or pull lends itself to any application where these characteristics would be beneficial. The fact that the manipulating arms can encircle a structure even though that structure may be fixed at both ends also lends itself to other applications, e.g., as a tool for use in laparoscopic applications.
Those skilled in the art will appreciate that the manipulator mechanism need not necessarily be sized for intra-jugular access, and that a longer, flexible shaft (that can be used in either femoral access applications or in IJ access applications in which non-longitudinal (non-straight) distal tip positioning is required) can be substituted.
The foregoing detailed description should be regarded as illustrative rather than limiting, and it should be understood that the following claims, including all equivalents, are intended to define the spirit and scope of this invention.
The present patent document claims the benefit of the filing date under 35 U.S.C. §119(e) of Provisional U.S. Patent Application Ser. No. 61/318,518, filed Mar. 29, 2010, which is hereby incorporated by reference.
Number | Date | Country | |
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61318518 | Mar 2010 | US |