Apparatus, System and Method for Performing an Electrosurgical Procedure

[0001] 1. Technical Field

[0002] The present disclosure relates to an apparatus, system and method for performing an electrosurgical procedure. More particularly, the present disclosure relates to an apparatus, system and method including a directional microwave antenna probe and a catheter that are configured to perform a microwave ablation procedure.

[0003] 2. Description of Related Art

[0004] Microwave ablation procedures, e.g., such as those performed for menorrhagia, are typically done to ablate the targeted tissue to denature or kill the tissue. Many procedures and types of devices utilizing electromagnetic radiation therapy are known in the art. Such microwave therapy is typically used in the treatment of tissue and organs such as the prostate, heart, and liver. One non-invasive procedure generally involves the treatment of tissue (e.g., a tumor) underlying the skin via the use of microwave energy. Typically, microwave energy is generated by a power source, e.g., microwave generator, and transmitted to tissue via a microwave antenna that is fed with a coaxial cable that operably couples to a radiating section of the microwave antenna.

[0005] To treat the tissue, the radiating section of the microwave antenna may be positioned inside the tissue of interest, e.g., the tumor, and microwave energy may be radiated thereabout. Typically, the microwave energy radiates with no specific directionality pattern, i.e., the direction of the microwave energy is not controlled. For example, under certain surgical environments, the microwave energy may radiate radially outward in a generally spherical pattern. While this spherical pattern of microwave energy may be suitable for treating certain shapes and/or types of tissue specimens, e.g., tissue specimens that exhibit a generally spherical shape, under certain circumstances, this spherical pattern of microwave energy may not be suitable for treating other shapes and/or types of tissue specimens, such as, for example, in the instance where the tumor is elongated or otherwise shaped.

[0006] The present disclosure provides a system for performing a microwave ablation procedure. The system includes a catheter including an open proximal end and a closed distal end configured to percutaneously access tissue. A directional microwave antenna probe adapted to connect to a source of microwave energy selectively couples to the catheter. The directional microwave antenna is rotatable within the catheter for directing the emission of microwave energy therefrom to tissue.

[0007] The present disclosure provides an apparatus for performing a microwave ablation procedure. The apparatus includes a catheter including an open proximal end and a closed distal end configured to percutaneously access tissue. A directional microwave antenna probe adapted to connect to a source of microwave energy selectively couples to the catheter. The directional microwave antenna is rotatable within the catheter for directing the emission of microwave energy therefrom to tissue.

[0008] The present disclosure also provides method of performing a microwave procedure. The method includes percutaneously accessing tissue with a catheter including an open proximal end and a closed distal end configured to percutaneously access tissue for adjacent placement thereto. A step of the method includes positioning a directional microwave antenna probe adapted to connect to a source of microwave energy into the catheter. The directional microwave antenna is rotatable within the catheter for directing the emission of microwave energy therefrom to tissue. And, transmitting microwave energy to the microwave antenna such that a desired tissue effect may be achieved is another step of the method.

[0020] Detailed embodiments of the present disclosure are disclosed herein; however, the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.

[0021] In the drawings and in the descriptions that follow, the term “proximal,” as is traditional, will refer to an end that is closer to the user, while the term “distal” will refer to an end that is farther from the user.

[0022] With reference to FIGS. 1A and 1B, a system for performing an electrosurgical procedure is designated 2. System 2 includes a directional microwave probe 4 and a catheter 6. Probe 4 is adapted to connect to one or more suitable electrosurgical energy sources, e.g., a microwave generator 8. In certain embodiments the probe 4 and catheter 6 are both adapted to couple to one or more fluid sources 10 that are configured to supply fluid to one or both of the probe 4 and catheter 6. In certain embodiments, the probe 4 and catheter 6 are both adapted to couple to one or more imaging guidance systems 7 that are configured to facilitate positioning the catheter 6 and/or probe 4 disposed therein adjacent tissue.

[0023] Continuing with reference to FIGS. 1A and 1B, and with reference to FIGS. 2-3, catheter 6 is illustrated. Catheter 6 is configured to percutaneously access tissue for adjacent placement thereto and to receive the probe 4 therein. With this purpose in mind, catheter 6 includes a proximal end 12, an elongated body portion or shaft 14 and a distal end 16. In the illustrated embodiment, the catheter includes an inlet/outlet port 17 of suitable dimensions that is operably disposed adjacent the proximal end 12. The inlet/outlet port 17 is in fluid communication with the fluid source 10 (via a supply hose not shown) and a lumen 24 (FIG. 3) of the catheter 6, to be described in greater detail below.

[0024] The proximal end 12 is configured to receive the probe 4 therethrough. More particularly, the proximal end 12 is configured to provide a substantially fluid-tight seal between the catheter 6 and the probe 4 when the catheter 6 and the probe 4 are coupled to one another (see FIG. 1B). To this end, a diaphragm 18 of suitable configuration is operably disposed at the proximal end 12 of the catheter 6 (FIGS. 1A-3).

[0025] Diaphragm 18 may be made from any suitable material including, but not limited to rubber, plastic, metal, metal alloy, etc. In the illustrated embodiment, the diaphragm 18 is made from rubber. A rubber diaphragm 18 facilitates providing the substantially fluid-tight seal between the catheter 6 and the probe 4 when the catheter 6 and the probe 4 are coupled to one another.

[0026] Diaphragm 18 includes a generally annular or circumferential configuration with an opening 20 of suitable configuration (FIG. 3) defined therein. Opening 20 is configured to facilitate receiving the probe 4 therethrough and providing the substantially fluid-fight seal between the catheter 6 and the probe 4. To this end, the opening 20 includes a diameter that is slightly smaller than a diameter of the probe 4. The opening 20 flexes or expands to accommodate the slightly larger diameter of the probe 4. That is, the opening 20 “gives” because of the elasticity attributed to the rubber diaphragm 18. In certain embodiments, it may prove useful to coat the diaphragm 18 (or in some instances the probe 4) with one or more types of lubricious materials, e.g., surgical jelly, PTFE, etc., to decrease the kinetic coefficient of friction between an interior wall of the opening 20 and an exterior surface of the probe 4. The opening 20 extends into the lumen 24 of the shaft 14.

[0027] Shaft 14 is suitably proportioned and operably coupled to the diaphragm 18. Shaft 14 includes a generally elongated configuration and may be made from any suitable material. More particularly, shaft 14 is configured such that when the probe 4 is coupled to the catheter 6, the probe 4 is capable of transmitting and/or emitting microwave energy through the shaft 14. With this purpose in mind, shaft 14 is made from a radiofrequency transparent material such as, for example, fiberglass and high temperature composite plastic e.g., polyimide, polyether, ketone, etc.

[0028] In certain instances, the shaft 12 and/or catheter 6 are configured to selectively receive a substantially rigid introducer sheath 15 of suitable proportion that is configured to add structural support to the catheter 6 and enhance visibility thereof during image-aided placement of the catheter 6 (FIG. 3). In this instance, the sheath 15 may be inserted into the catheter 6 prior to accessing tissue. When the catheter 6 is positioned adjacent tissue, the sheath 15 may be removed from the catheter 6 and the probe 4 may, subsequently, be inserted into the catheter 6.

[0029] In certain instances, the exterior surface of the shaft 14 may include markings that are configured to facilitate placement of the catheter 6 adjacent a tissue specimen. For example, and in certain instances, it may prove useful to provide the exterior surface of the shaft 14 with depth markings 13 (shown in phantom in FIG. 2) for indicating the depth of the inserted catheter in tissue. As noted above, the exterior of the shaft 14 may be coated with one or more lubricious materials for the reasons provided above.

[0030] Shaft 14 includes the lumen 24 that is configured such that the probe 4 is movable therein. More particularly, the lumen 24 is configured such that the probe 4 is translatable and rotatable therein; the significance of which to be described in greater detail below. That is, the probe 4 can move distally and proximally within the lumen 24, while maintaining a free rotational orientation thereabout. To this end, the lumen 24 includes diameter that is slightly larger than the diameter of the opening 20 (as best seen in FIG. 3) and a diameter of the probe 4 (as best seen in FIGS. 7A and 7B). Lumen 24 is in fluid communication with the inlet/outlet port 17 for providing a fluid, e.g., chilled saline, therein. The lumen 24 is configured to circulate the fluid from the inlet/outlet port 17 and into the probe 4 (see FIG. 1B in combination with FIG. 6). For illustrative purposes, the fluid flow is illustrated by directional arrows disposed within the lumen 24 and the probe 4. In certain instances, the lumen 24 is configured to circulate the fluid from the probe 4 and into the inlet/outlet port 17. Lumen 24 extends substantially along the length of the shaft 12 and culminates in a generally arcuate contour adjacent the distal end 16 of the catheter 6, see FIGS. 6-7B.

[0031] Distal end 16 is configured to pierce tissue such that the catheter 6 may be positioned adjacent (or in some instances into) a tissue specimen, e.g., a tumor. To this end, distal end 16 includes a generally pointed tip 26. Pointed tip 26 may include any shape that is suitable for the purposes intended herein. For illustrative purposes, the pointed tip 26 includes a generally conical shape. Pointed tip 26 may be made from any suitable material. In the illustrated embodiment, pointed tip 26 is made from a material such as metal, ceramic and plastic.

[0032] With reference again to FIGS. 1A and 1B, and with reference to FIGS. 4A and 5, probe 4 is illustrated. Probe 4 is configured to transmit and/or emit electrosurgical energy, e.g., microwave energy, to target tissue, e.g., a tumor, such that a desired tissue effect may be achieved, e.g., the tumor may be ablated. To this end, probe 4 includes a hub or handle 28 (FIG. 1A), a shaft 30 (FIGS. 1A and 4A) that is configured to support or house an internal coaxial feed or cable 32 (FIGS. 4A and 5), and a conductive distal end or tip 34 (FIGS. 1A, 1B, 4A and 5). In the illustrated embodiment, the probe 4 includes an inlet/outlet port 37 of suitable dimensions that is operably disposed on the handle 28 (FIGS. 1A and 1B). The inlet/outlet port 37 is in fluid communication with the fluid source 10 (via a return hose not shown) and a lumen 38 defined by a shaft 30 (FIGS. 5 and 6), to be described in greater detail below.

[0033] With continued reference to FIGS. 1A and 1B, handle 28 is suitably shaped. More particularly, handle 28 may be ergonomically designed to provide a user with an ease of use with respect to rotational and distal and/or proximal positioning within the catheter 6. With this purpose in mind, handle 28 includes a generally circumferential configuration that is configured to support the inlet/outlet port 37 and a connector 42 that couples to a power cable 44 that selectively couples to the microwave generator 8.

[0034] Power cable 44 may be any suitable power cable that is capable of conducting electrosurgical energy. Connector 42 provides electrosurgical energy to the conductive distal end 34 via the internal coaxial feed 32 that extends from the proximal end 46 of the probe 4 and includes an inner conductor tip 48 that is operatively disposed adjacent the distal end 34 (as best seen in FIG. 5). As is common in the art, internal coaxial feed 32 includes a dielectric material 43 and an outer conductor 45 surrounding each of the inner conductor tip 48 and dielectric material.

[0035] Shaft 30 is operably coupled to the handle 28 and is configured to house or support the internal coaxial feed 32 therein. In the illustrated embodiment, coaxial feed 32 is operably coupled to an internal frame of the shaft 30 by any suitable coupling methods.

[0036] Shaft 30 includes a generally elongated configuration with the internal cavity or lumen 38 extending along a length thereof. In the illustrated embodiment, shaft 30 is in fluid communication with the inlet/outlet port 37 via the lumen 38. The lumen 38 channels the fluid, e.g., chilled saline, from the catheter 6 to the inlet/outlet port 37 and ultimately back to the fluid source 10.

[0037] Shaft 30 may be made from any suitable material including, but not limited to plastic, metal, metal alloy, etc. In the illustrated embodiment, shaft 30 is made from a lightweight metal, such as, for example, aluminum.

[0038] Shaft 30 extends from the proximal end 46 of the probe 4 and includes or couples to the conductive distal end 34 by one or more suitable coupling methods, e.g., brazing, welding, soldering. In certain embodiments, shaft 30 may be monolithically formed with the conductive distal end 34.

[0039] With reference again to FIG. 4A, conductive distal end 34 is configured for directing the emission of electrosurgical energy. To this end, conductive distal end 34 includes a generally flared configuration with an aperture or opening 50 of suitable proportion (FIGS. 1A, 4A, and 5-7B) disposed adjacent a distal tip 52.

[0040] Distal tip 52 includes a generally arcuate configuration that is contoured to match the contour of the distal end of the lumen 24 of the catheter 6 (FIGS. 6 and 7A-7B). Matching the contours of the distal tip 52 and distal end of the lumen 24 facilitates directing fluid flow through the opening 50 when the distal tip 52 has “bottomed out” at or contacted the distal end of the lumen 24. That is, a substantially fluid-tight seal is present at a boundary between the distal tip 52 and distal end of the lumen 24 when the distal tip 52 has “bottomed out” at or contacted the distal end of the lumen 24 and forces the fluid through the opening 50.

[0041] Opening 50 extends along a length of the distal end 34 and includes a generally elongated configuration configured to maximize and/or concentrate electrosurgical energy transmission therefrom. To facilitate directing the electrosurgical energy from conductive distal tip 34 to tissue, the opening 52 is angled (see FIG. 4A in combination with FIGS. 4B and 4B₋₁). The angle of the opening 52 ranges from about 45° (FIG. 4B_—1) to about 250° (FIG. 4B).

[0042] Operation of system 2 is described in terms of use of a method for performing an electrosurgical procedure, e.g., a microwave ablation procedure. Catheter 6 with introducer sheath 15 disposed therein is used to percutaneously access underlying tissue (FIG. 6). In certain instances, the imaging guidance system 7 may be utilized to navigate the catheter 6 adjacent a tissue specimen of interest, e.g., a tumor. Once the catheter 6 is in position, the introducer sheath 15 is removed and the probe 4 is introduced into the lumen 24 of the catheter 6 via the opening 20 (FIGS. 1B and 6). A substantially fluid-tight seal is present between the opening 20 and the exterior surface of the shaft 30 of the probe 4 when the probe 4 is introduced into the catheter 6.

[0043] Thereafter, microwave generator 8 is activated and microwave energy is transmitted to the inner conductor tip 48 and emitted from the conductive distal tip 34 via the opening 50 (FIG. 7A). The opening 50 and the angle thereof facilitate directing the radiating microwave energy from the opening 50 to specific locations along the target tissue. Under certain surgical environments or conditions, it may prove necessary to treat different locations along the target tissue, in this instance, a user may translate and/or rotate the probe 4 within the lumen 24 of the catheter 6 (FIG. 7B). During the microwave procedure, it may prove useful to cool the inner conductor 48 and or conductive distal tip 34. In this instance, the fluid supply source 10 may be utilized to circulate fluid, e.g., chilled saline, to the inlet/outlet port 17 on the catheter 6 and through the lumen 24 (FIG. 6). The chilled saline returns through the opening 50 of the probe 4 and through the lumen 38 (FIG. 6) to the inlet/outlet port 37 where it is directed back to the fluid supply source via the return hose. As can be appreciated, the circulatory path of the chilled saline may be reversed. That is, the chilled saline may be supplied to the probe 4 and returned to the fluid supply source 10 via the catheter 6.

[0044] From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, it in certain embodiments, a perforated, non-conductive dielectric window 54 (FIG. 1A) may be operably positioned about the opening 52 to allow fluid flow while providing additional protection to the coaxial feed 32 including the inner conductor tip 48. More particularly, the non-conductive dielectric window 54 functions to protect to the coaxial feed 32 including the inner conductor tip 48 from adjacent tissue structure, bone matter, fluid, or other matter that may pose a possible threat to the coaxial feed 32 including the inner conductor tip 48 during the course of the electrosurgical procedure. For illustrated purposes, in FIG. 1A the non-conductive dielectric window 54 is shown separated from the opening 52. As can be appreciated, the non-conductive dielectric window 54 may be coupled to the opening 54 and/or the distal end 34 via one or more suitable coupling methods, e.g., an adhesive made from an epoxy resin.

[0045] While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.