METHODS AND SYSTEMS FOR ABLATION OF THE RENAL PELVIS
Apparatus, systems, and methods provide access to the renal pelvis of a kidney to treat renal nerves embedded in tissue surrounding the renal pelvis. Access to the renal pelvis may be via the urinary tract or via minimally invasive incisions through the abdomen and kidney tissue. Treatment is effected by exchanging energy, typically delivering heat or extracting heat through a wall of the renal pelvis, or by delivering active substances to ablate a thin layer of tissue lining at least a portion of the renal pelvis to disrupt renal nerves within the tissue lining of the renal pelvis.
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This application claims the benefit of the following three provisional patent applications: 61/937,353 (Attorney Docket No. 42532-707.101), filed Feb. 7, 2014; 62/003,918 (Attorney Docket No. 42532-708.101), filed May 28, 2014; and 62/074,894 (Attorney Docket No. 42532-707.102), filed Nov. 4, 2014; the entire contents of each of these applications are incorporated herein by reference.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates generally to medical devices, systems, apparatus, and methods for modifying nerve function and treating disease. More particularly, the present invention relates to methods and apparatus for delivering into or through the renal pelvis to modify sympathetic nerve activity in the adventitia of arteries and/or veins that surround the external surface of the renal pelvis in the kidney and in the afferent and efferent nerves within the muscles layers, urothelium and submucosa of the renal pelvis.
Hypertension, or high blood pressure, is a significant and growing health risk throughout the world. Hypertension can be caused by hyperactive renal sympathetic nerves which extend adjacent to the outside of the arteries and veins leading to a patient's kidney as well as within the wall of the renal pelvis. Renal nerve activity can be a significant cause of systemic hypertension, and it has long been known that disrupting renal nerve function can reduce blood pressure. More recently, hypertension therapies based on disrupting the renal nerves surrounding the renal arteries leading to the kidney (renal denervation) have been proposed and are described in the medical and patent literature.
Heretofore, most of the proposed renal denervation therapies have utilized an intravascular approach where a catheter is introduced into the arterial system and advanced to the main renal artery leading to the left or right kidney. Once located at a desired target site within the main renal artery, the catheter is used to deliver radiofrequency energy, heat, drugs, or the like to disrupt the function of the renal nerves which surround the artery. While effective, these techniques present a risk of injury to the renal artery and suffer from all the known disadvantages associated with intravascular access and therapies.
As an alternative to renal denervation through the renal arteries, ablation of the renal nerves through the renal pelvis has been proposed. Access to the renal pelvis can be obtained via the ureter, thus avoiding the need to perform intravascular procedures altogether.
For these reasons, it would be desirable to provide alternative protocols and apparatus for performing denervation or other renal nerve function disruptions via the renal pelvis. It would be further desirable if such protocols and apparatus could be performed minimally invasively, would present a reduced risk of injury and trauma to the patient, were economical, and could be performed using simplified and scalable methods. At least some of these objectives will be met by the inventions described herein below.
2. Description of the Background Art
U.S. Patent Publication Nos. 20011/0301662; 2013/0053732; and 2013/0178824 and WO2012/170482 describe apparatus, systems, and methods for ablating or modulating nerves or tissue via the renal pelvis. U.S. Patent Publication No. 2011/0060324 describes apparatus, systems, and methods for performing thermally-induced renal neuromodulation by intravascular access. U.S. Patent Publication No. 2011/0104061 describes apparatus, systems, and methods for active agents to the renal arteries for achieving renal denervation. Published PCT Application WO2010/067360 describes methods and apparatus for modifying blood pressure and kidney function via stimulation of the urinary tract by stimulating the renal nerves. U.S. Pat. No. 8,548,600 describes an intravascular electrode device for delivering energy which may include cylindrical electrodes on a helical deployment wire.
BRIEF SUMMARY OF THE INVENTIONThe present invention provides apparatus, systems, and methods for disrupting, inhibiting, denervating and/or modulating the activity of renal nerves present in a patient's kidney by exchanging energy or delivering active agents or substances to the renal wall or the nerves which lie within the wall of the renal pelvis or adjacent to the renal pelvis within the kidney. Most commonly, such renal denervation and/or modulation will be for the purpose of reducing blood pressure in patients suffering from and/or diagnosed with hypertension, but the methods and apparatus of the present invention could be used for treating patients diagnosed with other conditions as described below. The energy exchange is affected through a wall of the renal pelvis using an effector which has been positioned within the interior of the renal pelvis. The renal blood vessels, including the renal arteries and to a lesser extent the renal veins, enter the kidney in a branching network from the main renal artery and main renal vein leading to the kidney. The renal nerves are present in the adventitial tissue surrounding these branching blood vessels as well as in the tissue bed adjacent to the external wall of the renal pelvis. The renal nerves are also in the wall of the renal pelvis in the form of a dense nerve matrix consisting of both afferent and efferent nerves between the muscle layers as well as within the endothelium and submucosa.
In one specific aspect of the present invention, a method for inhibiting or modulating the function of renal nerves in a patient's kidney comprises introducing an effector into an interior of the kidney or an upper region of an adjacent ureter. Energy is exchanged and/or active substances are delivered from the interior of the kidney to ablate a layer of tissue lining at least a portion of the renal pelvis to disrupt renal nerves within the tissue lining of the renal pelvis. The tissue lining comprises a urothelium, a lamina propria, and two muscle layers, and ablation occurs primarily within the urothelium and the lamina propria. In some instances, the ablation may extend into a connective tissue and vascular layer that surrounds the lamina propria. Typically, the ablation extends to a depth in the range from 0.1 mm to 2 mm, preferably from 0.2 mm to 1.5 mm, and more preferably from 0.5 mm to 1.2 mm. In specific embodiments, electrical energy is delivered uniformly over a continuous region of the renal pelvis at a power in the range from 50 W to 200 W.
In another specific aspect of the present invention, apparatus, systems, and methods for disrupting, inhibiting, denervating and/or modulating the activity of renal nerves present in a patient's kidney deliver specific patterns of energy through the renal pelvis wall and to the renal nerves which lie within the wall of the renal pelvis or adjacent to the renal pelvis within the kidney. In particular, the present invention comprises an insulated electrode structure comprising a helical, preferably spiral, electrode deployment structure, typically a pre-shaped wire, which carries rounded, ovoid, or spherical electrodes for engaging and delivering electrical energy to tissue of or near the renal pelvis or other luminal and cavity-like body structures.
Such devices are particularly advantageous as they may be easily positioned by a steerable or other sheath to position the balls or other point electrodes in the center of the renal pelvis, or any other desired location. Since the sheath and the device are not locked together, the device can be rotated relative to the sheath. This allows the sheath to maintain its curve while the helix is rotated for better positioning.
The diameter of the balls is significantly larger than an outside diameter (OD) of the insulation on the supporting wire. An exemplary design has a ratio of 3.4:1 (0.078 in to 0.023 in) which allows the tissue to conform around the electrodes, ensuring that the electrodes will have a large contact surface area and excellent tissue contact. The geometry also helps guarantee a larger electrode-to tissue contact force. The larger contact surface area, improved electrode/tissue contact, and larger electrode/tissue contact force are all desirable for safe, proper, and efficient energy delivery and lesion geometry. The helical/spiral shape of the device will cause the balls to press against the walls of the renal pelvis. The spacing of the balls and the helical shape creates discreet lesions in the renal pelvis on different tissue planes. This ensures that there is enough healthy tissue left intact so that the pelvis and ureter do not stricture significantly.
In a first aspect of the present invention, a method for inhibiting or modulating the function of renal nerves in a patient's kidney comprises introducing an effector into an interior of the kidney or an upper region of an adjacent ureter. Energy is exchanged or active substances delivered from effector in the interior of the kidney to ablate a layer of tissue lining at least a portion of the renal pelvis to disrupt renal nerves within the tissue lining and optionally muscle layers of the renal pelvis. The layer typically includes the urothelium and the lamina propria. While the ablation occurs primarily within the urothelium and the lamina propria, in some instances ablation can extends into connective tissue and a vascular layer that surrounds the lamina propria and muscle layers.
The depth of ablation is controlled to achieve a desired ablation with minimal damage to the kidney and kidney function. Typically the ablation extends to a depth in the range from 0.1 mm to 2 mm, usually from 0.2 mm to 1.5 mm, and often from 0.5 mm to 1.2 mm. Such ablation depth can be achieved by delivering electrical energy, typically radiofrequency current, over a continuous region of the renal pelvis at a power in the range from 1 W to 200 W.
Introducing the effector may comprise advancing the effector through the urinary tract to the renal pelvis. For example, the effector may be disposed on a urinary catheter, and the urinary catheter may be advanced through the urethra, bladder, and ureter to reach the renal pelvis. Alternatively, introducing the effector may comprise advancing the effector percutaneously to the renal pelvis.
Energy may be delivered in a variety of ways. For example, the effector may comprise electrodes and the energy may comprise radiofrequency energy which is delivered to heat the wall of the renal pelvis and renal nerves embedded in the tissue bed surrounding the renal blood vessels. Alternatively, the effector may comprise an antenna and the energy may comprise microwave energy which is delivered to heat the wall of the renal pelvis and renal nerves embedded in the tissue bed surrounding the renal blood vessels. Further alternatively, the effector may comprise an ultrasound transducer and the energy may comprise ultrasound energy which is delivered to heat the wall of the renal pelvis and renal nerves embedded in the tissue bed surrounding the renal blood vessels. As a specific example of ultrasound energy, the ultrasound transducer may comprise a high intensity focused ultrasound transducer array. Other energy effectors may comprise a convective heat source which delivers heat through the renal pelvis to heat the wall of the renal pelvis and renal nerves embedded in the tissue bed surrounding the renal blood vessels. A specific example of a convective heat source would deliver a heated fluid within an inflated chamber deployed within the renal pelvis. Conversely, the effector may comprises a convective cooling source where heat is extracted through the renal pelvis to cool the wall of the renal pelvis and renal nerves embedded in the tissue bed surrounding the renal blood vessels. An exemplary convective cooling source comprises a cooled fluid deployed within an inflated chamber within the renal pelvis. Still other effectors may comprise a radiation-emitting source, either a radioisotope or an X-ray or other electronic radiation. Other examples include effectors having tissue-penetrating electrodes which are penetrated into a wall of the renal pelvis while energy is delivered to the wall through the electrodes. In yet other examples, the energy exchanged is mechanical energy such as abrasion or cutting.
In a second aspect of the present invention, an electrode structure comprises a self-expanding deployment wire having a distal region configured to expand into and engage a wall of a renal pelvis. A plurality of rounded electrode members is distributed over said distal region where each rounded electrode member has a surface which extends radially outwardly beyond the surface of the adjacent wire.
The distal region of the deployment wire typically has a three-dimensional expanded geometry, such as a helical or spiral distal geometry or may have a two-dimensional geometry, such as a looped distal end. Even lop structures, hover, may have secondary structures, such a bending or local coiling, to impart a third dimension to a planar geometry. Typically, at least the distal region of the deployment wire is electrically insulated over its surface between the rounded electrodes. The diameter of the rounded electrode structure may be from two-fold to six fold greater than that of the deployment wire, and exemplary electrode will have a deployment wire diameter in the range from 0.1 mm to 7 mm and a rounded electrode member diameter in the range from 0.25 mm to 2.5 mm. In specific embodiments, the rounded electrodes are ball electrodes.
The electrode structures are frequently incorporated in an electrode deployment assembly which comprises the electrode structure as above with a delivery tube having a central, passage. The electrode structure is reciprocatably received the central passage of the delivery, wherein the distal region of the deployment wire is radially constrained when present in the passage and radially expanded when advanced distally out of the passage. The electrode structure is usually free to rotate in the passage of the delivery tube.
In a third aspect of the present invention, a method for delivering energy to a renal pelvis comprises introducing a wire into the ureter adjacent to or within the renal pelvis. The wire has a pre-shaped distal region configured to conform to the renal pelvis. The distal portion of the wire is advanced into the renal pelvis, wherein the distal portion is radially constrained while being advanced, and the distal region of the wire is released from constraint within the renal pelvis to engage tissue over a wall of the renal pelvis. Energy is applied to the wall of the renal pelvis through a plurality of electrodes on the wire, wherein the electrodes have rounded surfaces (typically being ball electrodes) which extend beyond the surface of the adjacent wire and which embed into the renal pelvis wall.
In exemplary embodiments, a vacuum may be applied within the renal pelvis while applying energy to draw the walls of the renal pelvis against the rounded electrodes. The pre-shaped distal region of the wire may have a helical, spiral, looped or other two-dimensional or three-dimensional distal geometry. At least the pre-shaped distal region of the wire will usually be electrically insulated over its surface between the electrodes, and the diameter of the electrodes will usually be from two-fold to six fold greater than that of the wire. In specific embodiments, the wire has a diameter in the range set forth above and the electrodes have a diameter in the range set forth above. In an exemplary protocol, the distal portion of the wire is advanced into the renal pelvis from a central passage of a delivery tube which had been positioned in the renal pelvis, wherein the distal region is radially constrained when present in the passage and radially expanded when advanced distally out of the passage.
The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following drawings and detailed written description that set forth illustrative embodiments in which the principles of the invention are utilized.
The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
A patient's urinary tract is diagrammatically illustrated in
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Once in the renal pelvis RP, the effector 16 will be deployed in order to treat the renal nerves in accordance with the principles of the present invention. For example, the effector may comprise an expandable structure which is mechanically expanded or inflated within the renal pelvis to engage the interior walls of the pelvis as shown
In some instances, devices and methods will be configured to ablate a thin layer of tissue which lines the renal pelvic. The renal pelvic wall consists of multiple tissue layers as shown in
This result can be achieved with any number of devices, including those described in commonly owned U.S. Patent Publication 2013/0178824, the full disclosure of which is incorporated herein by reference, as well as a number of other devices described below. Energy or substance delivery through the devices must be carefully controlled to achieve the desired effect. Exemplary protocols will apply RF energy at high power (e.g. 50-200 Watts) and short application times (e.g. 0.1-15 seconds). In other instances, however, it may be possible to achieve similar ablation using low power (e.g. 1-50 Watts) and longer times (e.g. 60-300 seconds). Lesion depth should be between 0.1 mm and 2 mm, usually between 0.2 mm and 1.5 mm, and often between 0.5 mm and 1.2 mm.
Surface lesions having the desired depths can be created by regulating temperature, time, power, and/or impedance. More specifically, the lesion depth can be controlled by applying a specified power until specified impedance is reached. Alternatively, the lesion depth can be controlled by maintaining a specified temperature for a specified length of time. Under any control algorithm, time, power, temperature, and impedance can be monitored for safety limits.
An exemplary device 100 for delivering RF power to the renal pelvis is shown in
In other embodiments, the electrodes on the delivery catheter may comprise balloons with conductors formed over their external surfaces, e.g. by conductive inks or conductive wire.
In a further exemplary device 110, an expandable flex circuit 112 can be located over a balloon 114 or other inflatable/radially expandable structure, as shown in
Another approach to creating effective renal denervation lesions without damaging renal pelvic function is to create deeper lesions only in specific areas. This will leave healthy tissue intact, avoiding strictures in the renal pelvis. Multiple devices are disclosed below to achieve this effect.
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In still other embodiments, a single ball-electrode may be disposed at the distal end of a steerable catheter and may be used to create discreet lesions one-at-a-time. The user positions the ball to contact the tissue at the appropriate spots. The electrode can be monopolar or bipolar. A thermocouple may be secured inside or proximate to the ball for temperature measurement. The ball diameter is typically 0.02 in-0.10 in.
As an alternative to targeting the nerves embedded close to the surface the wall of the renal pelvis, it may be advantageous to target the nerves further away from the renal pelvic wall (e.g. nerves surrounding the renal arteries). The inventors herein have found that damaging the wall of the renal pelvis may be detrimental to proper function. Therefore, in these other embodiments, it would be advantageous to target nerves farther away from the renal pelvic wall, while leaving the renal pelvic wall intact. In addition, it would be advantageous to do this by accessing the renal pelvis, or anywhere along the ureter or kidney. Previously described ultrasound catheters deliver acoustic energy “to heat the wall of the renal pelvis and renal nerves embedded in the tissue bed surrounding the renal blood vessels”. This achieves reaching the farther nerves. In order to lessen risk of damaging the renal pelvic wall, the present invention can employ “focused” ultrasound transducers (high intensity focused ultrasound or HIFU) which can directly heat tissue surrounding the target nerves with minimal heating of the pelvic wall and the tissues immediately adjacent to the pelvic wall. Thus, an ultrasonic transducer catheter can access the renal pelvis through the ureter and deliver energy to tissue beyond the renal pelvic wall while keeping the renal pelvic wall intact with minimal heating.
Catheters according to the present invention may comprise tissue-penetrating elements in addition to the radiation-emitting elements which have been previously described. For example, the tissue-penetrating elements may comprise radio frequency electrodes, chemical delivery structures, heat delivery structures, cryogenic delivery structured, and the like.
The devices described above are mainly intended for transuretheral approaches. Most of these designs, however, are also suitable for a vascular approach where the renal nerves are targeted by passing a catheter through the renal artery and creating lesions through the artery. Current vascular approach renal denervation devices typically create helical lesions. Thus, all of the above designs that create helical lesions can be adapted for the vascular approach. Catheter sizes for such a vascular approach are in the range from 4 Fr to 8 Fr.
The renal nerve pathways may also be disrupted by mechanical means. In one embodiment, as illustrated in
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Mechanical denervation may also be accomplished using tools similar to those used for tissue biopsy, as shown in
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The device 230 may be delivered to the renal pelvis RP as shown in
In alternative configurations, each ball electrode can be independently turned on/off. A separate thermocouple can be fixed to each ball to monitor independent ball temperatures. The electrodes/wire can be stamped as shown in the Figure. These designs can be scaled down for renal denervation through the renal artery instead of through the renal pelvis.
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Applying RF or other heating means to the renal pelvis requires a balance of time and temperature. Too much energy will damage function of the renal pelvis. Not enough energy will prevent effective renal denervation. Experimentation has shown that a temperature in the range from 55° C. to 65° C., preferably 60° C. applied for time in the range from 1 minute to 3 minutes, preferably 2 minutes, is optimal to achieve ablation of nerves surrounding the renal pelvis and in some cases the ureter. As shown in
Many of the above described device designs dilate, stretch, or otherwise tension the wall of the renal pelvis during the application of energy, the mechanical treatment of the renal pelvic wall, or substance delivery. This stretching is advantageous as it thins the tissue wall bringing the nerves closer to the treatment elements, particularly for the delivery of RF current.
Claims
1. A method for inhibiting or modulating the function of renal nerves in a patient's kidney, said method comprising:
- introducing an effector into an interior of the kidney or an upper region of an adjacent ureter; and
- exchanging energy or delivering active substances from the interior of the kidney to ablate a layer of tissue lining at least a portion of the renal pelvis to disrupt renal nerves within tissue and muscle layers lining of the renal pelvis.
2. A method as in claim 1, wherein the tissue lining comprises a urothelium and a lamina propria and the ablation occurs primarily within the urothelium and the lamina propria.
3. A method as in claim 2, wherein the ablation extends into a connective tissue and vascular layer that surrounds the lamina propria.
4. A method as in claim 1, wherein the ablation extends to a depth in the range from 0.1 mm to 2 mm,
5. A method as in claim 1, wherein the ablation extends to a depth in the range from preferably from 0.2 mm to 1.5 mm.
6. A method as in claim 1, wherein the ablation extends to a depth in the range from and more preferably from 0.5 mm to 1.2 mm.
7. A method as in claim 4, wherein electrical energy is delivered uniformly over a continuous region of the renal pelvis at a power in the range from 1 W to 200 W.
8. A method as in claim 1, wherein introducing comprises advancing the effector through the urinary tract to the renal pelvis.
9. A method as in claim 8, wherein the effector is disposed on a urinary catheter and the urinary catheter is advanced through the urethra, bladder, and ureter to reach the renal pelvis.
10. A method as in claim 1, wherein introducing comprises advancing the effector percutaneously to the renal pelvis.
11. A method as in claim 1, wherein the effector comprises electrodes and the energy comprises radiofrequency energy which is delivered to heat the wall of the renal pelvis and renal nerves embedded in the tissue bed surrounding the renal blood vessels.
12. A method as in claim 1, wherein the effector comprises an antenna and the energy comprises microwave energy which is delivered to heat the wall of the renal pelvis and renal nerves embedded in the tissue bed surrounding the renal blood vessels.
13. A method as in claim 1, wherein the effector comprises an ultrasound transducer and the energy comprises ultrasound energy which is delivered to heat the wall of the renal pelvis and renal nerves embedded in the tissue bed surrounding the renal blood vessels.
14. A method as in claim 11, wherein the ultrasound transducer comprises a high intensity focused ultrasound transducer array.
15. A method as in claim 1, wherein the effector comprises a convective heat source and the energy comprises heat which is delivered through the renal pelvis to heat the wall of the renal pelvis and renal nerves embedded in the tissue bed surrounding the renal blood vessels.
16. A method as in claim 15, wherein the convective heat source comprises a heated fluid deployed within an inflated chamber within the renal pelvis.
17. A method as in claim 1, wherein the effector comprises a convective cooling source and the energy comprises heat which is extracted through the renal pelvis to cool the wall of the renal pelvis and renal nerves embedded in the tissue bed surrounding the renal blood vessels.
18. A method as in claim 17, wherein the convective cooling source comprises a cooled fluid deployed within an inflated chamber within the renal pelvis.
19. A method as in claim 1, wherein the effector comprises a radiation-emitting source.
20. A method as in claim 19, wherein the radiation-emitting source comprises a radioisotope or an electronic source.
21. A method as in claim 1, wherein the effector comprises tissue-penetrating electrodes which are penetrated into a wall of the renal pelvis while energy is delivered to the wall through the electrodes.
22. A method as in claim 1, wherein the energy exchanged is mechanical energy.
23. A method as in claim 22, wherein the mechanical energy comprises abrasion or cutting.
24. An electrode structure comprising:
- a self-expanding deployment wire having a distal region configured to expand into and engage a wall of a renal pelvis; and
- a plurality of rounded electrode members distributed over said distal region and having surfaces which extend radially outwardly beyond the surface of the adjacent wire.
25. An electrode deployment assembly as in claim 31, wherein the electrode structure is free to rotate within the passage of the delivery tube.
26. An electrode structure as in claim 24, wherein the distal region of the deployment wire has a looped distal end.
27. An electrode structure as in claim 24, wherein at least the distal region of the deployment wire is electrically insulated over its surface between the rounded electrodes.
28. An electrode structure as in claim 24, wherein the diameter of the rounded electrode structure is from two-fold to six fold greater than that of the deployment wire.
29. An electrode structure as in claim 28, wherein the deployment wire has a diameter in the range from 0.1 mm to 0.7 mm and the rounded electrode members have a diameter in the range from 0.25 mm to 2.5 mm.
30. An electrode structure as in claim 24, wherein the rounded electrodes are ball electrodes.
31. An electrode deployment assembly comprising:
- an electrode structure as in claim 24; and
- a delivery tube having a central, passage which reciprocatably receives the electrode structure, wherein the distal region is radially constrained when present in the passage and radially expanded when advanced distally out of the passage.
32. A method for delivering energy to a renal pelvis, said method comprising:
- introducing a wire into the ureter adjacent to or within the renal pelvis, wherein said wire has a pre-shaped distal region configured to conform to the renal pelvis;
- advancing the distal portion of the wire into the renal pelvis, wherein the distal portion is radially constrained while being advanced;
- releasing the distal region of the wire to engage tissue over a wall of the renal pelvis; and
- applying energy to the wall of the renal pelvis through a plurality of electrodes on the wire, wherein the electrodes have rounded surfaces which extend beyond the surface of the adjacent wire and which embed into the wall.
33. A method for delivering energy to a renal pelvis as in claim 32, further comprising applying a vacuum within the renal pelvis while applying energy to draw the walls of the renal pelvis against the rounded electrodes.
34. A method for delivering energy to a renal pelvis as in claim 32, wherein the pre-shaped distal region of the wire has a helical or spiral distal geometry.
35. A method for delivering energy to a renal pelvis as in claim 32, wherein the pre-shaped distal region of the wire has a looped distal end.
36. A method for delivering energy to a renal pelvis as in claim 32, wherein at least the pre-shaped distal region of the wire is electrically insulated over its surface between the electrodes.
37. A method for delivering energy to a renal pelvis as in claim 32, wherein the diameter of the electrodes is from two-fold to six fold greater than that of the wire.
38. A method for delivering energy to a renal pelvis as in claim 32, wherein the wire has a diameter in the range from 0.1 mm to 0.7 mm and the electrodes have a diameter in the range from 0.25 mm to 2.5 mm.
39. A method for delivering energy to a renal pelvis as in claim 32, wherein the electrodes are ball electrodes.
40. A method for delivering energy to a renal pelvis as in claim 32, wherein the distal portion of the wire is advanced into the renal pelvis from a central passage of a delivery tube which had been positioned in the renal pelvis, wherein the distal region is radially constrained when present in the passage and radially expanded when advanced distally out of the passage.
41. An electrode deployment assembly as in claim 31, wherein the electrode structure is free to rotate in the passage of the delivery tube.
Type: Application
Filed: Feb 6, 2015
Publication Date: Aug 13, 2015
Applicant: Verve Medical, Inc. (Peoria, AZ)
Inventors: Terrence J. Buelna (Santa Barbara, CA), Adam Gold (Glendale, AZ), Rahul Rao (Phoenix, AZ)
Application Number: 14/616,576