CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit, pursuant to 35 U.S. C. §119(e), of provisional U.S. Application Serial No. 60/958,482, filed July 6, 2007 entitled "Epicardium Payload Delivery Device" by Omar Lattouf, Robert Michael Webster, and Jason Poole, the disclosure for which is hereby incorporated herein in its entirety by reference. This application also claims the benefit, pursuant to 35 U.S. C. §119(e), of provisional U.S. Application Serial No. 61/001,213, filed October 31, 2007 entitled "Epicardium Payload Delivery Device" by Omar Lattouf, Robert Michael Webster, and Jason Poole, the disclosure for which is hereby incorporated herein in its entirety by reference.

Some references, if any, which may include patents, patent applications and various publications, are cited and discussed in the description of this invention. The citation and/or discussion of such references is provided merely to clarify the description of the present invention and is not an admission that any such reference is "prior art" to the invention described herein. All references cited and discussed in this specification are incorporated herein by reference in their entireties and to the same extent as if each reference was individually incorporated by reference.

FIELD OF THE INVENTION

The present invention generally relates to the field of cardiac health. More specifically, the present invention relates to the field of minimally invasive devices and methods for delivering a payload to a target area of the heart.

BACKGROUND OF THE INVENTION

Medical procedures on the heart can be performed inside the heart (endocardial) and on the outside of the heart (epicardial). Procedures performed on the epicardium of the heart include transmyocardial revascularization (TMR), cardiac mapping and ablation, pacing, endoscope delivery for visualization, biopsy, pericardial fluid capture, and delivery of stem cell and other biologically active agents, pharmaceutical agents, and bulking agents.

In order to deliver a payload to the epicardium, the pericardial sac that surrounds the heart must be penetrated. It would be advantageous to have a device and method for penetrating the pericardium at a single convenient location, such as to access multiple locations on the epicardium.

One challenge associated with delivery of a payload to the epicardium is that of the movement of the heart as it is beating. This movement creates a difficulty for locating a precise location on a beating heart and accordingly it is even more difficult to maintain a payload delivery device a precise location.

It would be advantageous to have a device and method for accessing the epicardium and delivering a payload to a particular location on the epicardium of a beating heart.

Therefore, a heretofore unaddressed need still exists in the art to address the aforementioned deficiencies and inadequacies.

SUMMARY OF THE INVENTION

The present invention, in one aspect, relates to a device for delivering a payload to the epicardium of the heart. In one embodiment, the device has a body portion with a proximal end and a distal end, a payload lumen extending through the body portion for delivering a payload to the epicardium of the heart, a payload port disposed at the proximal end of the body portion and in direct communication with the payload lumen for receiving a payload, an endoscopic lumen extending through the body portion, positioned underneath and in parallel to the payload lumen for guiding an endoscope, and an endoscopic port disposed at the proximal end of the body portion underneath the payload port, in direct communication with the endoscopic lumen for receiving an endoscope. The device further has a steerable tip disposed at the distal end of the body portion in direct communication with the payload lumen, a handle disposed at the proximal end of the body portion, where the body portion carries the payload lumen and the endoscope lumen and the payload port and endoscopic port are attached at its proximal end, a slideable actuator operatively associated with the handle for manipulating the steerable tip via a steering wire, and a separation means proximate the distal end of the body portion for increasing the separation distance between the epicardium and the distal end.

In one embodiment, the body portion is an elongate cylinder and the separation means allows the distal end of the steerable tip to be disposed immediately adjacent and substantially perpendicular to a target area on the epicardium. The separation means also allows the target area and a payload delivery to be viewed through an endoscope in the endoscopic lumen. The separation means includes a balloon, and further has an inflation lumen in direct communication with an inflation port disposed at the proximal end of the body portion and above the payload port, for inflating the balloon to increase the separation distance between the epicardium and the distal end. The endoscopic lumen extends through the balloon. The payload lumen delivers a liquid payload, an ablation catheter, a transmyocardial revascularization laser, a stem cell delivery means, and/or pacing leads.

In an alternative embodiment, the separation means has an expandable and collapsible mechanical means for increasing the separation distance between the epicardium and the distal end. In yet another alternative embodiment, the separation means has a second steerable tip for bending away from the body portion to increase the separation distance between the epicardium and the distal end of the device. The device can have a deployable foot member with a substantially concave cross-section, operatively associated with the expandable and collapsible mechanical means to increase the separation distance between the epicardium and the distal end. In another aspect, the present invention relates to a method for delivering a payload to the epicardium of the heart. In one embodiment, the method has the steps of providing a body portion with a proximal end and a distal end, providing a payload lumen extending through the body portion for delivering a payload to the epicardium of the heart, providing a payload port at the proximal end of the body portion, in direct communication with the payload lumen for receiving a payload, providing an endoscopic lumen extending through the body portion, positioned underneath and in parallel to the payload lumen for guiding an endoscope, and providing an endoscopic port at the proximal end of the body portion underneath the payload port, in direct communication with the endoscopic lumen for receiving an endoscope. The method further has the steps of providing a steerable tip at the distal end of the body portion in direct communication with the payload lumen, providing a handle at the proximal end of the body portion, where the body portion carries the payload lumen and the endoscopic lumen and the payload port and endoscopic port are attached at its proximal end, providing a slideable actuator at the distal end of the handle for manipulating the steerable tip via a steering wire, and providing a separation means proximate the distal end of the body portion for increasing the separation distance between the epicardium and the distal end.

In one embodiment, the method further has the steps of inserting the distal end of the body portion through a trocar placed in a chest wall, forming a hole in the pericardium, viewing a target area on the epicardium through the endoscope, engaging the slideable actuator to manipulate the steerable tip so as to position it immediately adjacent to and facing the target area on the epicardium, and delivering the payload through the payload lumen to the target area. The payload includes one or more of a liquid, an ablation catheter, a transmyocardial revascularization laser, pacing leads, and a stem cell delivery means.

In yet another aspect, the present invention relates to a device for delivering a payload to a target area of the heart. In one embodiment, the device has a body portion with a proximal end and a distal end, a first lumen extending through the body portion, a first port disposed at the proximal end of the body portion and in direct communication with the first lumen, a second lumen extending through the body portion, positioned underneath and in parallel to the first lumen, and a second port disposed at the proximal end of the body portion underneath the first port, in direct communication with the second lumen. The device further has a steerable member disposed at the distal end of the body portion in direct communication with the payload lumen, a handle disposed at the proximal end of the body portion, where the body portion carries the first lumen and the second lumen and the first port and second port are attached at its proximal end, an actuator disposed at the distal end of the handle for manipulating the steerable member, and a separation means proximate the distal end of the body portion for increasing the separation distance between the epicardium and the distal end.

In yet another aspect, the present invention relates to a method for delivering a payload to a target area of the heart. In one embodiment, the method has the steps of providing a body portion with a proximal end and a distal end, providing a first lumen extending through the body portion, providing a first port at the proximal end of the body portion, in direct communication with the first lumen, providing a second lumen extending through the body portion, positioned underneath and in parallel to the first lumen, providing a second port at the proximal end of the body portion underneath the first port, in direct communication with the second lumen, providing a steerable member at the distal end of the body portion in direct communication with the first lumen, providing a handle at the proximal end of the body portion, where the body portion carries the first lumen and second lumen and the first port and second port are attached at its proximal end, providing an actuator operatively associated with the distal end of the handle for manipulating the steerable member, and providing a separation means proximate the distal end of the body portion for increasing the separation distance between the epicardium and the distal end.

In one embodiment, the method further has the steps of inserting the distal end of the body portion through a trocar placed in a chest wall, viewing the target area of the heart through the second lumen, engaging the actuator to manipulate the steerable member so as to position it immediately adjacent to and facing the target area on the heart, and delivering a payload through the first lumen to the target area.

In yet another aspect, the present invention relates to a device for delivering a payload to the epicardium of a beating heart, having a body portion with a proximal end, a distal end, and a distal tip, a suction cup at the distal end in communication with a vacuum source at the proximal end, and a first lumen extending through the body portion for delivery of a payload to the epicardium. The device further has a second lumen connected to the suction cup for providing a vacuum, where the distal end is bendable and the suction cup is disposed at the distal tip. The suction cup provides for direct, firm contact with the heart surface, which may be advantageous in certain procedures such as placement of pacing leads.

In one embodiment, the device further has guide means for holding an endoscope, a handle and an actuator for moving the bendable distal end, and an inflatable balloon on the body portion, which provides a space to allow the bendable distal end to be positioned so as to be adjacent and perpendicular to the epicardium. The payload delivery lumen delivers one or more of a liquid payload, an ablation catheter, a transmyocardial revascularization laser, pacing leads, and a stem cell delivery means.

In yet another aspect, the present invention relates to a method for delivering a payload to the epicardium of a beating heart. In one embodiment, the method has the steps of providing a body portion having a suction cup at a distal end connected to a vacuum source and a first lumen extending through it, inserting the distal end through a trocar placed in a chest wall, forming a hole in the pericardium, inserting the distal end through the hole and positioning the distal end proximate to the area of the epicardium where the payload is to be delivered, activating the vacuum source and attaching the suction cup to the epicardium where the payload is to be delivered, and delivering the payload to the epicardium through the first lumen. The method further has the steps of providing a bendable tip and an inflatable balloon, inflating the balloon to hold the bendable tip away from the epicardium, and bending the bendable tip so as to place the suction cup against the epicardium.

In yet another aspect, the present invention relates to a device for delivering a payload to the epicardium of the heart. In one embodiment, the device has a body portion with a proximal end, a distal end, and a distal tip, a lumen through the body portion attached to the distal tip, for delivery of a payload to the epicardium through the distal tip, an endoscope guide attached to an outer wall of the body portion, with a distal end disposed proximate the distal end of the body portion, and an inflatable balloon disposed on the distal end of the endoscope guide which acts, when inflated, to hold the distal end of the body portion and the distal end of the endoscope guide away from the epicardium.

These and other aspects of the present invention will become apparent from the following description of the preferred embodiments, taken in conjunction with the following drawings, although variations and modifications therein may be affected without departing from the spirit and scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. IA shows schematically a perspective view of a device according to one embodiment of the present invention.

FIG. IB shows schematically a perspective view of the distal end of the device according to the embodiment shown in FIG. IA.

FIG. 1C shows schematically a perspective view of the proximal end of the device according to the embodiment shown in FIG. IA. FIG. ID shows schematically a partial view, taken from the proximal end of the device according to the embodiment shown in FIG. IA.

FIG. 2 shows schematically a partial view of a heart, with a device according to the embodiment of FIG. 1 inserted into the pericardial sac and positioned to deliver a payload to the epicardium, according to one embodiment of the present invention. FIG. 3A shows schematically a partial view of the distal end of a device positioned between the epicardium and pericardium of the heart, prior to activation of a separation means, according to one embodiment of the present invention.

FIG. 3B shows schematically a partial view of the device according to the embodiment shown in FIG. 3 A, following activation of the separation means, according to one embodiment of the present invention.

FIG. 4 shows schematically a partial view of a distal end of a device positioned between the epicardium and pericardium of the heart, with a second type of separation means following activation thereof, according to one embodiment of the present invention. FIG. 5 shows schematically a partial view of a distal end of a device positioned between the epicardium and pericardium of the heart, with a third type of separation means following activation thereof, according to one embodiment of the present invention. FIG. 6 shows schematically a partial view of a heart, with a device having a suction cup at the distal end, inserted into the pericardial sac and positioned to deliver a payload to the epicardium, according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The present invention is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Various embodiments of the invention are now described in detail. Referring to the drawings, like numbers indicate like components throughout the views. As used in the description herein and throughout the claims that follow, the meaning of "a", "an", and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.

The description will be made as to the embodiments of the present invention in conjunction with the accompanying drawings in FIGS. 1-6.

FIG. IA shows a perspective view of a device 100 according to one embodiment of the present invention. FIG. IB shows the distal end 132 of the device 100, and FIG. 1C shows the proximal end 134. A partial view of the device 100 as seen from the proximal end is shown by FIG. ID. In the embodiment of FIG. 2, the heart 210 is shown with a device 200 according to the embodiment of FIG. 1 inserted into the pericardial sac (see pericardium 212) proximate to the left ventricular apex 216 of the heart 210, and positioned to deliver a payload 202 to the epicardium 214. In the embodiment shown in FIG. 3A, the distal end 332 of the device 300 is positioned between the epicardium 314 and pericardium 312 of the heart, prior to activation of a separation means 340. FIG. 3B shows the device 300 after the separation means 340 has been activated.

In the embodiment shown in FIG. 4, the separation means 440 has an expandable and collapsible mechanical means 472, 474 for increasing the separation distance between the epicardium 414 and the distal end 432. FIG. 5 shows an embodiment in which the separation means 540 has a second steerable tip 576 for bending away from the body portion 522 to increase the separation distance between the epicardium 514 and the distal end 532. In the embodiment shown in FIG. 6, device 600 delivers a payload 602 to the epicardium 614 of a beating heart 610. The device has a body portion 622 with a proximal end 634, a distal end 632, and a distal tip 624, a suction cup 684 at the distal end 632 in communication with a vacuum source 686 at the proximal end 634, and a first lumen 630 extending through the body portion 622 for delivery of a payload 602 to the epicardium 614.

Referring now to FIG. 1, the present invention, in one aspect, relates to a device for delivering a payload to the epicardium of the heart. In one embodiment, the device has a body portion 122 with a proximal end 134 and a distal end 132. The device further has a payload lumen 130 extending through the body portion 122, for delivering the payload to the epicardium of the heart, a payload port 152 disposed at the proximal end 134 of the body portion 122 and in direct communication with the payload lumen 130, for receiving the payload, an endoscopic lumen 144 extending through the body portion 122, positioned underneath and in parallel to the payload lumen 130, for guiding an endoscope 150, and an endoscopic port 145 disposed at the proximal end 134 of the body portion 122 underneath the payload port 152, in direct communication with the endoscopic lumen 144, for receiving an endoscope 150. The device further has a steerable tip 124 disposed at the distal end 132 of the body portion 122, in direct communication with the payload lumen 130. A handle is disposed 126 at the proximal end 134 of the body portion 122, wherein the body portion 122 carries the payload lumen 130 and the endoscopic lumen 144, and wherein the payload port 152 and endoscopic port 146 are attached at its proximal end 134. A slideable actuator 128 is operatively associated with the handle 126, for manipulating the steerable tip 124 via a steering wire (not shown), and a separation means 140 is proximate the distal end 132 of the body portion 122, for increasing the separation distance between the epicardium and the distal end 132. In one embodiment, the body portion 122 of the device 100 is an elongate cylinder and the separation means 140 allows the distal end of the steerable tip 124 to be disposed immediately adjacent and substantially perpendicular to a target area (see FIG. 3, 390) on the epicardium. The separation means 140 allows the target area on the epicardium and a payload delivery to be viewed through an endoscope 150 in the endoscopic lumen 144. As shown, the separation means 140 is a balloon and the device 100 further has an inflation lumen 142 in direct communication with an inflation port 154 disposed at the proximal end 134 of the body portion 122 and above the payload port 152, for inflating the balloon of the separation means 140 to increase the separation distance between the epicardium and the distal end 132. The endoscopic lumen 144 extends through the balloon 140, and the payload lumen 130 can deliver a payload (see FIG. 2, 202) in the form of a liquid, a mapping or ablation catheter, a transmyocardial revascularization laser, a stem cell delivery means, pacing leads, a bulking agent, a diagnostic agent, and/or another biologically active agent such as stem cells.

Referring now to FIG. 4, in one embodiment the separation means 440 of the device can have an expandable and collapsible mechanical means 472, 474 for increasing the separation distance between the epicardium 414 and the distal end 432. A deployable foot member 474 with a substantially concave cross-section is operatively associated with the expandable and collapsible mechanical means 472, 474.

Alternatively, as shown in FIG. 5, in one embodiment the separation means 540 has a second steerable tip 576 for bending away from the body portion 522 to increase the separation distance between the epicardium 514 and the distal end 532.

In another aspect, referring now to FIG. 2, the present invention relates to a method for delivering a payload 202 to the epicardium 214 of the heart 210. In one embodiment, the method has the steps of providing a body portion 222 having a proximal end 234 and a distal end 232, providing a payload lumen 230 extending through the body portion 222, for delivering a payload 202 to the epicardium 214 of the heart 210, and providing a payload port 252 at the proximal end 234 of the body portion 222, in communication with the payload lumen 230, for receiving a payload 202. The method further has the steps of providing an endoscopic lumen 244 extending through the body portion 222, positioned underneath and in parallel to the payload lumen 230 for guiding an endoscope 250, providing an endoscopic port 246 at the proximal end 234 of the body portion 222 underneath the payload port 252, in direct communication with the endoscopic lumen 244, for receiving an endoscope 250, and providing a steerable tip 224 at the distal end 232 of the body portion 222, in direct communication with the payload lumen 230.

In one embodiment, the method further has the steps of providing a handle 226 at the proximal end 234 of the body portion 222, wherein the body portion 222 carries the payload lumen 230 and the endoscopic lumen 244 and wherein the payload port 252 and endoscopic port 246 are attached at its proximal end 234, providing a slideable actuator 228 at the distal end of the handle 226 for manipulating the steerable tip 224 via a steering wire (not shown), and providing a separation means 240 proximate the distal end 232 of the body portion 222, increasing the separation distance between the epicardium 214 and the distal end 232. In one embodiment, the method further has the steps of inserting the distal end

232 of the body portion 222 through a trocar placed in a chest wall, forming a hole in the pericardium 212, viewing a target area (see FIG. 3, 390) on the epicardium 214 through the endoscope 250, engaging the slideable actuator 228 to manipulate the steerable tip 224 so as to position it immediately adjacent to and facing the target area on the epicardium 214, and delivering the payload 202 through the payload lumen 230 to the target area. The payload 202 includes one or more of a liquid, an ablation catheter, a transmyocardial revascularization laser, pacing leads, and a stem cell delivery means. In yet another aspect, the present invention relates to a device for delivering a payload 202 to a target area of the heart 210. In one embodiment, the device has a body portion 222 with a proximal end 234 and a distal end 232, a first lumen 230 extending through the body portion, a first port 252 disposed at the proximal end 234 of the body portion and in direct communication with the first lumen 230, a second lumen 244 extending through the body portion 222, positioned underneath and in parallel to the first lumen 230, and a second port 250 disposed at the proximal end 234 of the body portion 222 underneath the first port 252, in direct communication with the second lumen 244.

In one embodiment, the device further has a steerable member 224 disposed at the distal end 232 of the body portion 222 in direct communication with the payload lumen 230, a handle 226 disposed at the proximal end 234 of the body portion 222, wherein the body portion 222 carries the payload lumen 230 and the endoscope lumen 244 and the first port 252 and second port 250 are attached at its proximal end, an actuator 228 disposed at the distal end of the handle 226, for manipulating the steerable member 224, and a separation means 240 proximate the distal end 232 of the body portion 222, for increasing the distance between the epicardium 214 and the distal end 232. In yet another aspect, the present invention relates to a method for delivering a payload 202 to a target area. In one embodiment, the method has the steps of providing a body portion 222 having a proximal end 234 and a distal end 232, providing a first lumen 230 extending through the body portion 222, providing a first port 252 at the proximal end 234 of the body portion 222, in direct communication with the first lumen 230, providing a second lumen 244 extending through the body portion 222, positioned underneath and in parallel to the first lumen 230, and providing a second port 250 at the proximal end 234 of the body portion 222 underneath the first port 252, in direct communication with the second lumen 244.

In one embodiment, the method further has the steps of providing a steerable member 224 at the distal end 234 of the body portion 222 in direct communication with the first lumen 230, providing a handle 226 at the proximal end 234 of the body portion 222 that carries the payload lumen 230 and the endoscopic lumen 244, and providing a first port 252 and second port 250 at its proximal end. The method further has the steps of providing an actuator 228 that is operatively associated with the handle 226, for manipulating the steerable member 224, and a providing a separation means 240 proximate the distal end 232 of the body portion 222, for increasing the separation distance between the epicardium 214 and the distal end 232.

In one embodiment, the method further has the steps of inserting the distal end 232 of the body portion 222 through a trocar placed in a chest wall, viewing the target area of the heart 210 through the second lumen 244, engaging the actuator 228 to manipulate the steerable member 224 so as to position it immediately adjacent to and facing the target area on the heart 210, and delivering a payload 202 through the first lumen 230 to the target area. Now referring to FIG. 6, in yet another aspect, the present invention relates to a device 600 for delivering a payload 602 to the epicardium 614 of a beating heart 610. In one embodiment, the device has a body portion 622 with a proximal end 634, a distal end 632, a distal tip 624, a suction cup 684 at the distal end 632 in communication with a vacuum source 686 at the proximal end 634, and a first lumen 630 extending through the body portion 622 for delivery of a payload 602 to the epicardium 614. The suction cup 684 provides for direct, firm contact with the surface of the heart 610 (e.g. epicardium 614), which may be advantageous in certain procedures such as placement of pacing leads. The body portion 622 also has a second lumen 644 connected to the suction cup 684 for providing a vacuum. The distal end 632 is bendable, and the suction cup 684 is disposed at the distal tip 624. The device 600 further has guide means 644 for holding an endoscope 650, a handle 626, and an actuator 628 for moving the bendable distal end 632.

In one embodiment, the device further has inflatable balloon 640 on the body portion 622, which provides a space to allow the bendable distal end 632 to be positioned so as to be adjacent and perpendicular to the epicardium 614, where the first lumen 630 delivers one or more of a liquid payload, an ablation catheter, a transmyocardial revascularization laser, pacing leads, and a stem cell delivery means.

In yet another embodiment, the present invention relates to a method for delivering a payload 602 to the epicardium 614 of a beating heart 610. In one embodiment, the method has the steps of providing a body portion 622 having a suction cup 684 at a distal end 632 connected to a vacuum source 686 and a first lumen 630 extending through it, inserting the distal end 632 through a trocar placed in a chest wall, forming a hole in the pericardium 612, and inserting the distal end 632 through the hole and positioning the distal end 632 proximate to the area 690 of the epicardium 614 where the payload 602 is to be delivered. The method further has the steps of activating the vacuum source 686 and attaching the suction cup 684 to the epicardium 614 where the payload 602 is to be delivered, and delivering the payload 602 to the epicardium 614 through the first lumen 630. The method further has the steps of providing a bendable tip 624 and an inflatable balloon 640, inflating the balloon 690 to hold the bendable tip 624 away from the epicardium 614, and bending the bendable tip 624 so as to place the suction cup 684 against the epicardium 614.

Although the devices and methods of the present invention according to the embodiments of FIGS. 2 and 6 have been shown as inserted through the pericardium near the left ventricular apex, the device can be inserted through any site on the pericardium. The body portion of the device can preferably be about 2 to 18 inches in length, where the bendable tip makes up the distal 0.5-4 inches, and most desirably about 0.7-2 inches. The body portion is preferably made of a stiff material such as polyetheretherketone (PEEK) or polystyrene for the non-bendable parts of the body portion and a softer material such as polyurethane for the bendable parts. Preferably the body portion is stiff enough to be pushable and maneuverable and the tip is desirably soft enough to be bent and manipulated accordingly. The outer diameter of the body is preferably about 5 to 45 French. The size of the payload lumen should be appropriately sized for the application, but it is desirably large enough to accept an instrument ranging in diameter from about 2 - 30 Fr. For example, it could be sized such that a catheter delivering a payload could be inserted through the payload lumen.

The actuator can manipulate the distal tip via a steering wire, and the device may accordingly have a third lumen for carrying the wire. More than one wire can be used, and the steerable tip can be controlled by various means. Desirably the tip can be rotated 360 degrees and bent at an angle up to 180 degrees. Ways of steering and bending the tip are taught in U.S. Serial No. 11/784,385, now U.S. Publication No. US/2008/004597 Al, published on January 3, 2008, which is herein incorporated by reference in its entirety. It teaches the use of a single steering wire connected to a handle that allows bending of a bendable tip up to 90° or more. The tip can be rotated by twisting the handle. The steering wire is fastened to the distal tip and the handle using adhesive or a swaged collar, for example. Other means for making a bendable tip are known in the art and can be used, alternatively.

The foregoing description of the exemplary embodiments of the invention has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.

The embodiments were chosen and described in order to explain the principles of the invention and their practical application so as to activate others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.