Anchored RF Ablation Device for The Destruction of Tissue Masses

Abstract

The inventive ablation element comprises an elongated cannula having a proximal end and a distal end. The cannula defines an internal lumen and a cannula axis. A plurality of conductors contained within the lumen, each having a proximal end proximate the proximal end of the cannula, and a distal end proximate the distal end of the cannula. A plurality of ablation stylets each has a proximal end and a distal end, and each coupled to the distal end of a respective conductor, the conductors together with their respective stylets being mounted for axial movement. A trocar point defined proximate the distal end of the cannula. A deflection surface positioned between the trocar point and the proximal end of the cannula, the deflection surface being configured and positioned to deflect at least some of the stylets laterally with respect to the cannula axis in different directions defining an ablation volume.

Claims

1. An ablation element, comprising: (a) an elongated cannula having a proximal end and a distal end, said cannula defining an internal lumen within said cannula and a cannula axis; (b) a plurality of conductors contained within said lumen, each of said conductors having a proximal end proximate the proximal end of said cannula, and a distal end proximate the distal end of said cannula; (c) a plurality of ablation stylets each having a proximal end and a distal end, and each coupled at the respective proximal end of said stylet to the distal end of a respective conductor, said stylets comprising a deflectable material, said conductors together with their respective stylets being mounted for axial movement; (d) a trocar point defined proximate the distal end of said cannula; and (e) a deflection surface positioned between said trocar point and said proximal end of said cannula, the deflection surface being configured and positioned to deflect, in response to axial movement of said stylets in a direction from said proximate end of said cannula to said distal end of said cannula, at least some of said stylets laterally with respect to said cannula axis in different directions along substantially straight paths, said paths defining an ablation volume.

2. An ablation element as in claim 1, wherein said conductor is selected from the group consisting of electrical conductors, radio frequency conductors, microwave conductors and optical conductors.

3. An ablation element as in claim 1, wherein each of said conductors are integral with its respective ablation stylet.

4. An ablation element as in claim 1, wherein the solid contents of said lumen consist essentially of said conductors.

5. An ablation element as in claim 1, wherein each of said stylets are configured to assume a substantially straight configuration in the absence of external forces.

6. An ablation element as in claim 1, further comprising: (f) a motor member or members coupled to said conductors to drive axial movement of said stylets in directions from said proximal end of said cannula to said distal end of said cannula, and from said distal end of said cannula to said proximal end of said cannula through a plurality of positions.

7. An ablation element as in claim 1, wherein said trocar point is defined at the distal end of a trocar member, said trocar member having an outside surface, said cannula having an outside surface, said trocar member having a proximal end secured proximate to the distal end of said elongated cannula, and the outside surface of said cannula and the outside surface of said trocar point defining a trocar surface.

8. An ablation element as in claim 7, wherein said deflection surface comprises a number of ramps defined proximate the proximal end of said trocar point, the distal ends of said stylets being positionable proximate to said ramps and within said trocar surface.

9. An ablation element as in claim 8, wherein said conductors are electrical conductors, said stylets are electrical conductors, and each of said stylets are configured to assume a substantially straight configuration in the absence of external forces.

10. An ablation element as in claim 9, wherein said deflection surface comprises a plurality of channels guiding said distal ends of said stylets to said ramps.

11. An ablation element as in claim 9, wherein said cannula is secured to said trocar member with the outside surface of said cannula proximate to the outside surface of said trocar member.

12. An ablation element as in claim 1, further comprising: (f) an anchor mounted for movement between an internal position disposed within said trocar surface and an anchoring position extending laterally from said trocar surface through points external of said lumen; and (g) a drive member disposed within said lumen and coupled to said anchor to drive said anchor between said internal position and said anchoring position.

13. An ablation element as in claim 9, wherein said anchor comprises at least two pointed members mounted for movement in directions which have vector components which extend away from the axis or said cannula and away from each other.

14. An ablation element as in claim 13, wherein said pointed members extend in a direction with vector component that extends in a direction opposite to the direction in which said trocar point extends.

15. An ablation element as in claim 1, wherein said conductors bear against each other at least along a portion of their length within said cannula.

16. An ablation element, comprising: (a) an elongated cannula having a proximal end and a distal end, said cannula defining an internal lumen within said cannula and a cannula axis; (b) a plurality of conductors contained within said lumen, each of said conductors having a proximal end proximate the proximal end of said cannula, and a distal end proximate the distal end of said cannula; (c) a plurality of ablation stylets each having a proximal end and a distal end, and each coupled at the respective proximal end of said stylet to the distal end of a respective conductor, said stylets comprising a deflectable material, said conductors together with their respective stylets being mounted for axial movement; (d) a front end defined proximate the distal end of said cannula; and (e) a deflection surface positioned between said front end and said proximal end of said cannula, the deflection surface being configured and positioned to deflect, in response to axial movement of said stylets in a direction from said proximate end of said cannula to said distal end of said cannula, at least some of said stylets laterally with respect to said cannula axis in different directions along substantially straight paths, said paths defining an ablation volume.

17. An ablation element as in claim 16, wherein said conductors bear against each other at least along a portion of their length within said cannula.

18. An ablation element as in claim 16, wherein said conductors are driven by a drive mechanism which allows said conductors to move independently.

19. An ablation element as in claim 16, wherein said conductors have a length, a width and a thickness, said width being greater than said thickness.

20. An ablation element as in claim 16, wherein said conductors terminate in a point oriented to allow deflection by said deflection surface.

21. An ablation element as in claim 16, wherein said conductors extend in different directions when they exit the deflection surface and extend to a variable extent.

22. An ablation element as in claim 16, wherein said conductors are driven by a drive circuit which varies the amount of energy supplied to the stylets and/or the length of the stylets and/ or the length of the stylets and/or the time during which power is supplied to the stylets and/or the angular orientation of the ablation element.

23. An ablation element as in claim 22, wherein the parameters of stylet length, stylet power, stylet actuation time and/or angular orientation are controlled by a computer in response to a computer program having an input comprising feedback information from the tissue area being operated on and/or a preset program.

24. An ablation element, comprising: (a) an elongated cannula having a proximal end and a distal end, said cannula defining an internal lumen within said cannula and a cannula axis; (b) a plurality of conductors contained within said lumen, each of said conductors having a proximal end proximate the proximal end of said cannula, and a distal end proximate the distal end of said cannula; (c) a plurality of ablation stylets each having a proximal end and a distal end, and each coupled at the respective proximal end of said stylet to the distal end of a respective conductor, said stylets comprising a deflectable material, said conductors together with their respective stylets being mounted for axial movement; (d) a front end defined proximate the distal end of said cannula; (e) an anchor mounted for movement between an internal position disposed within said trocar surface and an anchoring position extending laterally from said trocar surface through points external of said lumen; and (f) a drive member disposed within said lumen and coupled to said anchor to drive said anchor between said internal position and said anchoring position, wherein said anchor comprises at least two pointed members mounted for movement in directions which have vector components which extend away from the axis or said cannula and away from each other.

25. An ablation element as in claim 24, wherein said front end is a trocar point defined at the distal end of a trocar member, said trocar member having an outside surface, said cannula having an outside surface, said trocar member having a proximal end secured proximate to the distal end of said elongated cannula, and the outside surface of said cannula and the outside surface of said trocar point defining a trocar surface.

26. An ablation element as in claim 25, wherein said trocar member bears a deflection surface, said deflection surface comprising a number of ramps defined proximate the proximal end of said trocar point, the distal ends of said stylets being positionable proximate to said ramps and within said trocar surface.

27. An ablation element as in claim 24, wherein said anchors extend in directions which have vector components which extend away from the distal end of said of ablation element.

28. An ablation element as in claim 24, wherein said anchors are deployed in response to rotary motion.

29. An ablation element as in claim 24, wherein said anchors are deployed by bearing against a deflection surface.

30. An ablation element as in claim 24, wherein said anchors are made of a springy material which assumes a curved configuration when not subjected to external forces. In accordance with a particularly preferred embodiment of the invention, it is contemplated that a graphical user interface and a pair of electrical switches, for example a joystick and a pushbutton, will be used to switch between operating parameter options for the inventive catheter which are displayed on a graphical user interface or other information conveying device such as an audio cue generator. The surgeon navigates, for example, using a joystick looking at or hearing electronically generated audio signal, such as a voice, presenting various options and selects that option by pushing the electrical switch. In principle, this can be done on a single switch incorporating joystick and pushbutton features. Optionally, the electrical switches which operate the system may be recessed partially or fully in order to minimize the likelihood of unintentional actuation. Additional protection is provided by requiring two motions within a relatively short period of time in order to achieve a change in the control of the system. In accordance with a particularly preferred version of the invention, this is achieved by having a human voice present options and acknowledge instructions. This allows the surgeon to operate without having to look away from visual displays guiding the operation, the patient, instruments and so forth, thus removing potential losses of information. In accordance with the invention it is contemplated that laser manufacturing techniques are used to manufacture the anchors and perhaps the anchor deflection surfaces. Preferably, the point of the trocar is milled to a point with three surfaces. Stylets are milled and orientation which cooperates with the deflection surfaces which deflect them. A cooperating low friction insulator ring, for example, made of Teflon, cooperates with the deflection surfaces to deflect hypotube electrode stylets. The present invention contemplates the use of rearwardly deployed anchoring stylets which act as retractable barbs for maintaining the position of the trocar point during forward deployment of the radiofrequency (RF) electrode ablation stylets. In accordance with the present invention, a stylet operating member, optionally a stylet push member, which may be a tube, is positioned on one side of a tubular compression/ tension operator, for example on the inside of the compression/tension operator. Similarly, in accordance with the present invention, and anchor member operating member, optionally an anchor poll member, which may be a tube, is positioned on the other side of a tubular compression/ tension operator, for example on the outside of the compression/tension operator. Such outside placement is particularly advantageous in the case where the anchoring member is of relatively wide dimension and large size. In accordance with a preferred embodiment of the invention, the compression tension operator is secured at the proximal end to the handle of the ablation instrument and at the distal and to the anchoring member deflection surface and the hypotube electrode stylet deflection surface. The invention contemplates a plurality of hypotube electrode stylets which are bound together as a unitary structure and advanced by a single push tube or wire. It is also contemplated that the inventive instrument will include channels for flushing clean. In accordance with the inventive system, the frequency with which flushing should be performed is minimized through the use of a trocar font face which is substantially closed (except for a single undeflected hypotube which exits the front face of the trocar) and providing for exit of hypotubes through the cylindrical side wall of the trocar point. In accordance with a particularly preferred embodiment of the invention, the anchor member is separate from the anchor push tube, and is connected it to by mating or other interlocking structure. Deflection surfaces for both the hypotube stylets and anchors are selected to result in strains in the range of two to 8%, preferably about 4%, for example 3.5% to 4.5%, which represents a reasonable compromise between instrument longevity and a relatively large amount of deflection. And insulation sleeve between the anchors and the hypotube stylets in order to allow separate electrical actuation and ablation with either or both of the anchors and the hypotube stylets. The hypotube stylets contained thermocouples which are used to measure the temperature of a plated tissue. Thus ensuring that the tissue will be raised to the correct temperature for a sufficient period of time to a blatant tissue resulting in the creation of necrotic tissue which may be absorbed by the body. In accordance with the preferred embodiment of the invention, hypotube stylets are deployed forwardly or distally while anchors are deployed in a proximal direction or rearwardly. Alternatively, the hypotube stylets may be deployed in a proximal direction or rearwardly, while anchors are deployed forwardly or distally.

31. An ablation element, comprising: (a) an elongated cannula having a proximal end and a distal end, said cannula defining an internal lumen within said cannula and a cannula axis; (b) a plurality of ablation stylets, each of ablation stylets having a proximal end and a distal end, said ablation stylets being joined to each other in the configuration where said distal ends of said ablation stylets are free to be deflected, said ablation stylets forming a unitary ablation stylet array, said unitary ablation stylet array being mounted for sliding movement with respect to said elongated cannula, and said ablation stylets comprising a deflectable material; (c) an ablation stylet sliding member, said ablation stylet sliding member having a proximal end proximate the proximal end of said cannula, and a distal end positionable proximate the distal end of said cannula, said ablation stylet sliding member being mounted for sliding movement with respect to said cannula, and said ablation stylet sliding member being an effective conductor of energy; and (d) a trocar point assembly defining a trocar point, said trocar point assembly being secured to said cannula proximate the distal end of said cannula, said trocar point assembly comprising: (i) a plurality of tracks for receiving and guiding sliding movement of said ablation stylets; and (ii) a plurality of stylet deflection surfaces positioned between said trocar point and said proximal end of said cannula, the stylet deflection surfaces being configured and positioned to deflect, in response to axial movement of said stylets in a direction from said proximate end of said cannula to said distal end of said cannula, at least one of said stylets away from said cannula axis and in different directions along substantially straight paths, said straight paths defining an ablation volume.

32. An ablation element as in claim 31, further comprising: (e) an anchors, said anchor having a proximal end and a distal end, said anchor having an end free to be deflected, said anchor forming a unitary anchoring array, said unitary anchoring array being mounted for sliding movement with respect to said elongated cannula, and said anchor comprising a deflectable material; (f) an anchor sliding member, said anchor sliding member being mounted for sliding movement with respect to said cannula, and said anchor sliding member being an effective conductor of energy; and wherein said trocar point assembly further comprises: (iii) an anchor deflection surface positioned between said trocar point and said proximal end of said cannula, the anchor deflection surface being configured and positioned to deflect, in response to axial movement of said anchor, said anchor away from said cannula axis to act as a barb.

33. An ablation element as in claim 32, wherein a graphical user interface and a pair of electrical switches, for example a joystick and a pushbutton, will be used to switch between operating parameter options for the inventive catheter which are displayed on a graphical user interface or other information conveying device such as an audio cue generator, the surgeon navigates, for example, using a joystick looking at or hearing electronically generated audio signal, such as a voice, presenting various options and selects that option by pushing the electrical switch, optionally using a single switch incorporating joystick and pushbutton features.

34. An ablation element as in claim 32, wherein electrical switches which operate the system may be recessed partially or fully in order to minimize the likelihood of unintentional actuation, with optional additional protection is provided by requiring two motions within a relatively short period of time in order to achieve a change in the control of the system.

35. An ablation element as in claim 34, wherein a human voice present options and acknowledge instructions, allowing the surgeon to operate without having to look away from visual displays guiding the operation, the patient, instruments and so forth, thus removing potential losses of information.

36. An ablation element as in claim 32, wherein laser manufacturing techniques are used to manufacture the anchors and perhaps the anchor deflection surfaces.

37. An ablation element as in claim 32, wherein the point of the trocar is milled to a point with three surfaces. Stylets are milled and orientation which cooperates with the deflection surfaces which deflect them. A cooperating low friction insulator ring, for example, made of Teflon, cooperates with the deflection surfaces to deflect hypotube electrode stylets.

38. An ablation element as in claim 32, wherein rearwardly deployed anchoring stylets which act as retractable barbs for maintaining the position of the trocar point during forward deployment of the radiofrequency (RF) electrode ablation stylets.

39. An ablation element as in claim 32, wherein a stylet operating member, optionally a stylet push member, which may be a tube, is positioned on one side of a tubular compression/tension operator, for example on the inside of the compression/tension operator, and in accordance with the present invention, and anchor member operating member, optionally an anchor poll member, which may be a tube, is positioned on the other side of a tubular compression/tension operator, for example on the outside of the compression/tension operator and such outside placement is particularly advantageous in the case where the anchoring member is of relatively wide dimension and large size.

40. An ablation element as in claim 32, wherein the compression tension operator is secured at the proximal end to the handle of the ablation instrument and at the distal and to the anchoring member deflection surface and the hypotube electrode stylet deflection surface.

41. An ablation element as in claim 32, wherein a plurality of hypotube electrode stylets which are bound together as a unitary structure and advanced by a single push tube or wire.

42. An ablation element as in claim 32, wherein channels for flushing clean and the frequency with which flushing should be performed is minimized through the use of a trocar font face which is substantially closed (except for a single undeflected hypotube which exits the front face of the trocar) and providing for exit of hypotubes through the cylindrical side wall of the trocar point.

43. An ablation element as in claim 32, wherein the anchor member is separate from the anchor push tube, and is connected it to by mating or other interlocking structure.

44. An ablation element as in claim 32, wherein deflection surfaces for both the hypotube stylets and anchors are selected to result in strains in the range of two to 8%, preferably about 4%, for example 3.5% to 4.5%, which represents a reasonable compromise between instrument longevity and a relatively large amount of deflection.

45. An ablation element as in claim 32, wherein an insulation sleeve is positioned between the anchors and the hypotube stylets in order to allow separate electrical actuation and ablation with either or both of the anchors and the hypotube stylets.

46. An ablation element as in claim 32, wherein the hypotube stylets contain thermocouples which are used to measure the temperature of ablated tissue, thus ensuring that the tissue will be raised to the correct temperature for a sufficient period of time to ablate tissue resulting in the creation of necrotic tissue which may be absorbed by the body.

47. An ablation element as in claim 32, wherein hypotube stylets are deployed forwardly or distally while anchors are deployed in a proximal direction or rearwardly, or the hypotube stylets may be deployed in a proximal direction or rearwardly, while anchors are deployed forwardly or distally.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG. 1 is a plan view of the multiple antenna ablation device of the invention with the cover removed and partially in cross-section to illustrate its operation;

[0046] FIG. 2 is a front view of the inventive probe with anchor system of the device along lines 2-2 of FIG. 1, but illustrating the instrument after deployment of the anchor;

[0047] FIG. 3 is a cross-sectional view of the tip of the catheter constructed in accordance with the present invention;

[0048] FIG. 4 is a plan view of the apparatus of the present invention with anchors and ablation hypotubes not deployed;

[0049] FIG. 5 is a plan view of the catheter with seven hypotube ablation electrodes and four anchors deployed;

[0050] FIG. 6 is a perspective view of the catheter structure of FIG. 5;

[0051] FIG. 7 is a cross-sectional view illustrating deployed hypotubes and anchors;

[0052] FIG. 8 is a plan view illustrating a trocar point with deflection surfaces for guiding hypotubes;

[0053] FIG. 9 is a perspective view illustrating a trocar point with deflection surfaces for guiding hypotubes;

[0054] FIG. 10 is a top plan view illustrating a trocar point with deflection surfaces for guiding hypotubes;

[0055] FIG. 11 is a bottom plan view illustrating a trocar point with deflection surfaces for guiding hypotubes;

[0056] FIG. 12 is a rear view illustrating a trocar point with deflection surfaces for guiding hypotubes;

[0057] FIG. 13 is a perspective view illustrating a core for holding a plurality of hypotubes;

[0058] FIG. 14 is a side plan view illustrating a core for holding a plurality of hypotubes;

[0059] FIG. 15 is a rear view illustrating a core for holding a plurality of hypotubes;

[0060] FIG. 16 is a side plan view illustrating a core holding a plurality of hypotubes;

[0061] FIG. 17 is a perspective view illustrating a core holding a plurality of hypotubes;

[0062] FIG. 18 is a rear view illustrating a core holding a plurality of hypotubes;

[0063] FIG. 19 is a perspective detailed view illustrating a core holding a plurality of hypotubes;

[0064] FIG. 20 is a perspective detailed view illustrating the tips of a plurality of hypotubes when they are being held in a core as illustrated in FIG. 19;

[0065] FIG. 21 is a side plan view illustrating a rearward anchoring member;

[0066] FIG. 22 is a perspective view illustrating a rearward anchoring member;

[0067] FIG. 23 is an end view illustrating a rearward anchoring member;

[0068] FIG. 24 is a plan view illustrating a rearward anchoring member;

[0069] FIG. 25 is an end view illustrating an anchor deflecting mandrel member;

[0070] FIG. 26 is a perspective view illustrating an anchor deflecting mandrel member;

[0071] FIG. 27 is a perspective view of an insulating ring for insulating the hypotube electrodes from the anchors;

[0072] FIG. 28 is a cross-sectional view of an insulating ring for insulating the hypotube electrodes from the anchors along lines 28-28 of FIG. 27;

[0073] FIG. 29 is a side view of the insulating ring for insulating the hypotube electrodes from the anchors;

[0074] FIG. 30 is a perspective view illustrating the anchor push tube;

[0075] FIG. 31 is a side plan view illustrating the anchor push tube in accordance with the present invention;

[0076] FIG. 32 is partially cross-sectional view, similar to FIG. 1 illustrating the inventive instrument with anchors and hypotubes deployed;

[0077] FIG. 33 is a detail perspective view illustrating deployment of anchors and hypotube ablation stylets; and

[0078] FIG. 34 is a detail perspective view similar to FIG. 33 illustrating full deployment of hypotubes and anchors in an alternative embodiment of the invention.

DETAILED DESCRIPTION OF THE BEST MODE

[0079] Referring to FIG. 1, an ablation instrument 10 constructed in accordance with the present invention is illustrated. Instrument 10 comprises a catheter portion 12 and a handle portion 14. Ablation instrument 10 is illustrated with one of the two mating handle halves removed and partially in cross section, in order to reveal its internal parts and workings in connection with the following description.

[0080] Referring to FIGS. 1 and 2, the inventive ablation instrument 10 is illustrated in the fully retracted position suitable for advancement of catheter portion 12 into tissue, for example, tissue to be subjected to ablation by being treated with radiofrequency energy. In this position, the catheter 12 present a simple thin smooth pointed surface well-suited to penetrate healthy tissue while doing minimal damage. At the same time, the sharpness of the point and the relatively stiff, though somewhat flexible, nature of catheter 12 enables accurate steering of the point and control of the path of penetration. In the case of the treatment of uterine fibroids, such steering is achieved largely by manipulation of the uterus coupled with advancement of the catheter 12.

[0081] Handle portion 14 includes a pair of actuators namely a stylet actuator 16 and an anchoring actuator 18. Stylet actuator 16 includes a serrated surface 20. Anchoring actuator 18 includes a pair of serrated surfaces, namely an anchor retraction surface 22 and an anchor deployment surface 24. The application of relatively great force is facilitated by a wall 26, against which the thumb or other finger of the surgeon may bear during the respective deployment and retraction phase of an operation performed using the inventive ablation instrument 10.

[0082] Stylet actuator 16 and anchoring actuator 18 are supported within handle portion 14. Handle portion 14 comprises a left housing half 28 and a right housing half 30 symmetrical in shape to left housing half 28, as illustrated in FIG. 2.

[0083] As illustrated in FIGS. 1, 3 and 4, the inventive ablation instrument may be configured in the undeployed state. Alternatively, as illustrated in FIGS. 2, 5, 6 and 7, the inventive ablation instrument 10 may be configured either the anchors or the ablation stytlets in a deployed state, or as illustrated in FIGS. 2, 5, 6 and 7 with anchors and stylets both fully deployed.

[0084] Referring to FIG. 7, ablation instrument 10 is terminated in a trocar 32, which defines a pointed tip 34. Trocar 32 also functions as an electrode mandrel to deflect the tissue ablation stylets in various directions, as appears more fully below. Trocar 32 is illustrated in FIGS. 8-12. Trocar 32 has a pointed tip 34, defined by bottom surface 36 and side surfaces 38 and 40, as illustrated most clearly in FIG. 8. Surfaces 36, 38 and 40 ground into the distal portion 42 of trocar 32. Trocar 32 also includes a central channel 44 which extends through the length of trocar 32 and is centered on the central axis of trocar 32.

[0085] A plurality of deflection surfaces 46 are positioned at the end of longitudinal grooves 48, as illustrated in FIG. 9. These surfaces 46 are configured to gently bend the flexible hypotubes which are excited with radiofrequency energy during the ablation of uterine fibroid tissue, causing them to exit catheter 12 and follow substantially straight paths through the tissue to be ablated. During this deflection, the action of deflection surfaces 46 is complemented by the inside curved surface 50 of insulative Teflon deflector ring 52.

[0086] In accordance with an especially preferred embodiment of the invention, stylets 54 are made of a nickel titanium alloy instead of stainless steel. In this case, the configuration of deflection surfaces 46 is shaped to maximize the deflection without over straining the nickel titanium alloy material of the stylets. More particularly, in accordance with the preferred embodiment of the invention, surfaces 46 are configured to result in a strain less than eight percent. Strains in the range of 2%-8% will work with strains in the range of about 4%, for example 3.5% to 4.5%, representing an easy to implement commercial solution. Less than 2% strain does not provide appreciable bending with today's technology. Higher performance may be obtained by maintaining a deflection angle which results in a strain of 6-7%. Configuring surface 46 to result in strains approaching 8%, for example 7.5% will maximize deflection and flexibility in design of ablation volume, but will tend to result in quicker degradation of hypotube stylets 54. However, if a particular procedure does not involve a great number of ablations, or the use of several disposable ablation catheters 10 is acceptable, such devices under certain circumstances do present advantages.

[0087] The deflection of a plurality of hypotubes 54 is illustrated in FIG. 7. Hypotubes 54 are flexible hollow tubes made of steel or nickel titanium alloy. Hypotubes 54, as well as all other steel parts of the inventive ablation device 10, are preferably, for economic and/or performance reasons, made of stainless steel or other high quality steel, except as indicated herein. The tubes define an internal volume 56 which contains a wire thermocouple, which performs the function of measuring the temperature of the ablated tissue which, over time, allows control of the ablation operation and ensures that the ablated tissue will become necrotic. In FIG. 7, the thermocouples 56 are shown in only one of the tubes for purposes of clarity of illustration.

[0088] Hypotubes 54 slidably move in longitudinal grooves 48. Hypotubes 54, which function as ablation electrodes, are mounted on a needle core 58, illustrated in FIGS. 13-15. Needle core 58 includes a plurality of longitudinal grooves 60. Each of six hypotubes 54 is mounted in its respective longitudinal groove 60 and secured in groove 60 by friction or through the use of an adhesive. A seventh hypotube 62 is mounted in a central axial bore 64. The assembly of hypotubes 54 and 62 in needle core 58 is illustrated in FIGS. 16-18. The mounting of hypotubes 54 in needle core 58 is illustrated most clearly in perspective in FIG. 19.

[0089] As illustrated most clearly in FIG. 20, hypotubes 54 are preferably oriented with the flat surfaces 65 of their points oriented to slidingly cooperate with deflection surfaces 46 during deployment of the hypotubes. This is done by having the pointed tips of hypotubes 54 radially displaced from the center of catheter 12, which prevents the pointed tips of the hypotubes from digging into deflection surfaces 46.

[0090] A flexible steel electrode push tube 66 is disposed around and secured to needle core 58 with the needles mounted in it. Sliding movement of the hypotubes 54 in longitudinal grooves 48 is achieved by movement of electrode push tube 66. Movement in direction 68 causes the deployment of hypotubes 54 and 62. Movement in direction 70 causes retraction of the hypotubes.

[0091] Referring to FIGS. 5 and 7, a flexible steel electrode mandrel tube 74 is disposed around and over electrode push tube 66. Flexible steel electrode mandrel tube 74 allows electrode push tube 66 to freely slide within it. This is achieved, despite the relatively large area of the tubes, because the facing surfaces of the tubes are both smooth and because there is a small gap between their facing surfaces, thus minimizing friction. Such gaps allow provision for flushing the instrument clean with water, as is done with prior art devices. A flexible plastic tubular insulative member 76 is disposed around and over electrode mandrel tube 74.

[0092] Insulative member 76 isolates electrical radiofrequency ablation energy (carried by push tube 66 for exciting hypotubes 54 and 62) from anchor push tube 78. This allows electrical ablation energy to be optionally applied to anchor push tube 78 to independently cause the anchors 80 on anchor member 82 to apply ablation energy to a different volume than that which is ablated by the electrode stylets 54 and 62. Anchor member 82 is illustrated in FIGS. 21-23. Anchors 80 are cut using a laser from a steel tube to form steel anchor member 82. Each anchor 80 has a tip 84 which is bent radially outwardly to facilitate deflection over anchor mandrel 86 in response to movement of anchor member 82 in the direction of arrow 70.

[0093] Anchor mandrel 86 is illustrated in FIGS. 24-26. Anchor mandrel 86 incorporates a number of deflection surfaces 88, as illustrated most clearly in FIGS. 7 and 26. In accordance with an especially preferred embodiment of the invention, anchor member 82, and thus anchors 80, are made of a nickel titanium alloy instead of stainless steel. Nickel titanium alloy is a preferred material for both anchors 80 and stylets 54.

[0094] The configuration of deflection surfaces 88 is shaped to maximize the deflection without over-straining the nickel titanium alloy material of the anchors. More particularly, in accordance with the preferred embodiment of the invention, surfaces 88 are configured to result in a strain less than eight percent. Strains in the range of 2-8% will work with strains in the range of about 4%, for example 3.5 to 4.5%, are less rigorously 3% to 5%, representing an easy to implement commercial solution. Higher performance may be obtained by maintaining a deflection angle which results in a strain of 6-7%. Configuring surface 88 to result in strains approaching 8%, for example 7.5% will maximize deflection and flexibility in design of ablation volume, but will tend to result in quicker degradation of anchors 80. However, if a particular procedure does not involve a great number of ablations, or the use of several disposable ablation catheters 10 is acceptable, such devices under certain circumstances do present advantages.

[0095] The structure of the distal end of catheter portion 12 is completed by a steel anchor cover 90, which is supported on, surrounds and is secured to insulating ring 52 whose structure is illustrated in FIGS. 27-29. During deflection, anchors 80 pass between deflection surfaces 88 and the inside surface of steel anchor cover 90.

[0096] Anchor push tube 78, illustrated in FIGS. 30 and 31 includes a pair of keys 92 which are shaped like the letter T. Keys 92 mate with slots 94 in anchor member 82. Anchor member 82 and anchor push tube 78 thus act as a unitary member during deployment and retraction of anchors 80, in response to sliding motion of anchor member 82 and anchor push tube 78.

[0097] The structure of catheter 12 is completed by outer tube 96 which is secured to handle 14 at one end and secured to a tubular slip ring 98 which slides over anchor push tube 78.

[0098] FIG. 1 illustrates the relative positions of anchoring actuator 18, and stylet actuator 16 before deployment of anchors and stylets. This corresponds to FIG. 4.

[0099] Electrode mandrel tube 74 is secured at its proximal end to handle 14. At its distal end, electrode mandrel tube 74 is secured to trocar 32, for example by a quantity of epoxy adhesive 100 in the annular groove 102 on trocar 32, as illustrated in FIG. 3. Stylet actuator 16 is secured to electrode push tube 66. Thus, movement in the direction of arrow 68 in FIG. 1 causes the stylets to emerge from the end of the catheter as illustrated in FIGS. 5, 6, 7 and 32. Full deployment of ablation electrodes or stylets 54 and 62 is illustrated most clearly in FIG. 33.

[0100] Anchoring actuator 18 is secured to anchor push tube 78. At its distal end, electrode mandrel tube 74 is secured to anchor mandrel 86, for example by a quantity of epoxy adhesive. Accordingly, movement of anchoring actuator 18, in the direction of arrow 70 in FIG. 1, causes the anchors 80 to emerge from the catheter as illustrated in FIGS. 5, 6, 7 and 32. Full deployment of anchors 80 is illustrated most clearly in FIG. 33.

[0101] In accordance with the present invention it is contemplated that control of the inventive ablation device 10 will be achieved by one or two electrical switches 104 and 106. Operation of switch 106 will cause the appearance of a menu on a display, for example by axial movement of switch 106 in the manner of a joystick. Transverse movement of switch 106 causes the menu to switch between different menu items, such as controlling ablation time, controlling ablation temperature, or some other parameter. Selection of the desired value for the selected parameter is achieved by transverse motion of switch 106, causing the various values to be displayed on the display. When the desired value is seen on the screen by the surgeon, depression of switch 104 registers that value with the electronic circuit controlling ablation and causes the inventive ablation device 10 to be operated in accordance with the selected parameter.

[0102] RF ablation energy, control signals, and temperature measurement signals are coupled from the inventive ablation device 10 to a control unit/RF energy source by a connector 108. In accordance with the present invention, it is contemplated that a conventional radiofrequency energy source such as that used in conventional ablation systems would be employed in conjunction with the inventive ablation device 10.

[0103] In accordance with the present invention, cauterization radiofrequency energy may also be applied to trocar 32 during withdrawal of trocar 32 from the patient in order to control loss of blood. It is noted that the nature of the RF signal needed to achieve cautery is different from the nature of an ablation signal. Both of these signals are well defined in the art. Likewise, their generation is also well-known. However, in accordance of the present invention conventional cautery and conventional ablation signals may be used for cautery and ablation, respectively.

[0104] An alternative embodiment of the inventive catheter 112 is illustrated in FIG. 34. Here anchors 180 are positioned distally of ablation electrodes 154.

[0105] While the inventive device has been illustrated for use in the ablation of uterine fibroids, it is understood that this particular implementation is exemplary and that the inventive device may be employed in a wide variety of circumstances. Likewise, while an illustrative embodiment of the invention has been described, it is understood that various modifications to the structure of the disclosed device will be obvious to those of ordinary skill in the art. Such modifications are within the spirit and scope of the invention which is limited and defined only by the appended claims.