# Patent

## Title
Energy delivery conduits for use with electrosurgical devices

## Abstract

A conduit assembly for transmitting energy between an electrosurgical energy generator and an energy delivering device comprises a first cable sub-assembly including a cable having a flexibility and an energy attenuation; a second cable sub-assembly including a cable having a flexibility and an energy attenuation; wherein the flexibility of the cable of the first cable sub-assembly is less than the flexibility of the cable of the second cable sub-assembly; and wherein the energy attenuation of the cable of the first cable sub-assembly is less than the energy attenuation of the cable of the second cable sub-assembly.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. application Ser. No. 13/740,706 filed Jan. 14, 2013, which is a continuation of U.S. patent application Ser. No. 11/805,052 filed on May 22, 2007, now U.S. Pat. No. 8,353,901, the entire disclosure of each of which is incorporated herein by reference.


BACKGROUND
1. Technical Field
The present disclosure relates to electrosurgical systems, and more particularly, to energy delivery conduits for use with electrosurgical devices during RF and/or microwave ablation procedures.
2. Background of Related Art
Energy delivery conduits, including coaxial cables are well known in the art and its applications are numerous. Coaxial cables are typically used, in surgical procedures, to transfer energy from one point to another while minimizing losses during said transmission.
Although many kinds of coaxial cables have been designed, for the most part, these devices serve primarily as energy transmission conduits. Aside from transmitting energy, it is often desirable to have coaxial cables with different characteristics and features.
SUMMARY
The present disclosure relates to a conduit assembly for transmitting electrosurgical energy between an electrosurgical generator and an energy delivering device. The conduit assembly comprises a first cable sub-assembly including a cable; and a second cable sub-assembly including a cable. The flexibility of the cable of the first cable sub-assembly is less than the flexibility of the cable of the second cable sub-assembly. Further, the energy attenuation of the cable of the first cable sub-assembly is less than the energy attenuation of the cable of the second cable sub-assembly. In one embodiment, the diameter of the first cable sub-assembly is larger than the diameter of the second cable sub-assembly. In another embodiment, the length of the first cable sub-assembly is greater than the length of the second cable sub-assembly.
The conduit assembly may further include a connector assembly. The connector assembly includes a first connector operatively connected to a first end of the cable of the first cable sub-assembly and a second connector operatively connected to the second end of the cable of the second cable sub-assembly. The first and second connecters are matable with one another to electrically connect the cable of the first cable sub-assembly with the cable of the second cable sub-assembly.
Additionally, the cable of the first cable sub-assembly includes an inner conductor surrounded by a dielectric material and an outer conductor surrounding the dielectric material. The cable of the second cable sub-assembly also includes an inner conductor surrounded by a dielectric material and an outer conductor surrounding the dielectric material.



BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the presently disclosed conduit assemblies are disclosed herein with reference to the drawings, wherein:
FIG. 1 is a perspective view of a conduit assembly according to an embodiment of the present disclosure shown attached between an energy delivering device and an electrosurgical energy generator;
FIG. 2 is a side elevational view of a first cable assembly of the conduit assembly of FIG. 1;
FIG. 3 is a longitudinal cross-sectional view of a portion of the first cable assembly of the conduit cable assembly of FIGS. 1 and 2, as taken through 3-3 of FIG. 2;
FIG. 4 is a side elevational view of second cable assembly of the conduit assembly of FIGS. 1-3;
FIG. 5 is a longitudinal cross-sectional view of the second cable assembly of the conduit assembly of FIGS. 1-3, as taken through 5-5 of FIG. 4;
FIG. 6 is a perspective view of a conduit assembly according to another embodiment of the present disclosure;
FIG. 7 is a perspective view of a conduit assembly according to still another embodiment of the present disclosure;
FIG. 8 is a side elevational view of a conduit assembly according to a further embodiment of the present disclosure shown attached between an energy delivering device and an electrosurgical energy generator; and
FIG. 9 is a longitudinal cross-sectional view of a portion of the conduit assembly of FIG. 8, as taken through 9-9 of FIG. 8.



DETAILED DESCRIPTION
Embodiments of the presently disclosed energy transmission conduit assembly are now described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein, the terms “distal” refers to that portion of the conduit assembly, or component thereof, farther from the user while the term “proximal” refers to that portion of the component thereof, closest to the user.
Electrosurgical energy delivering systems employ electrosurgical energy (e.g., RF or microwave) to ablate tissue at a specific target site. During electrosurgical procedures, electrosurgical energy delivering systems directly apply therapeutic energy to a desired tissue location to ablate said tissue.
Electrosurgical energy delivering systems include an electrosurgical energy generator “G” (i.e., RF and/or microwave generator), an energy delivery device or instrument “D” having a probe, needle, antenna, and/or knife and at least one energy delivery conduit interconnecting the energy delivering device “D” and the generator “G”.
The energy transmission conduit assembly hereinbelow described is intended to be used with a microwave energy delivering system. It is contemplated, however, that the energy transmission conduit assembly described below may be utilized with any suitable electrosurgical system known in the art. The described energy transmission conduit assembly is designed to minimize loss of energy along or throughout a length thereof.
Referring initially to FIGS. 1-5, an energy transmission conduit assembly in accordance with an embodiment of the present disclosure, is generally referred to as reference numeral 100. Conduit assembly 100 includes a first cable sub-assembly 104 configured and adapted for connection to an electrosurgical energy generator “G” via a generator connector 102, a second cable sub-assembly 108 configured and adapted for connection to an energy delivering device “D” via a device connector 110, and a cable connector assembly 106 configured and adapted to interconnect first cable sub-assembly 104 and second cable sub-assembly 108 to one another.
As seen in FIG. 2, first cable sub-assembly 104 includes a cable 105 configured to transmit electrosurgical energy, a generator connector 102 operatively connected to a first end of cable 105 and configured and adapted for connection to generator “G”, and a first connector 106a of cable connector 106 operatively connected to a second end of cable 105.
Generator connector 102 may include an insulative or dielectric covering 102a such as a polyolefin heat-shrink tubing, as depicted in FIG. 2. Other suitable dielectric materials, known by those having skill in the art, may be used to electrically insulate generator connector 102. In addition to generator connector 102, adapters (not shown) may be used to interconnect electrosurgical energy generator “G” to first cable sub-assembly 104 if generator connector 102 is not properly sized or does not properly mate with electrosurgical energy generator “G”.
With reference to FIG. 3, cable 105 of first cable sub-assembly 104 comprises an inner conductor 112 surrounded by a dielectric material 114, and an outer conductor 116 surrounding dielectric material 114 and encompassed by an outer sheath 118. Dielectric material 114 may be formed of any suitable low energy loss material such as low density or ultra-density PolyTetraFluoroEthylene (“PTFE”), cellular high density polyethylene or the like. Outer sheath 118 may be comprised of any suitable electrically insulative material known in the art such as fluorinated ethylene propylene (“FEP”) or polyolefin.
It is contemplated that cable 105 of first cable sub-assembly 104 may be flexible or semi-rigid. Accordingly, inner conductor 112 of cable 105 may be flexible (i.e., having a stranded transverse cross-sectional profile or any other suitable flexible structure known in the art) or semi-rigid (i.e., having a solid transverse cross-section profile or any other semi-rigid structure known in the art). Outer conductor 116 may be flexible (i.e., made of braided silver plated cooper or any other suitable material known in the art) or semi-rigid (i.e., be fabricated of solid cooper or any other suitable material known in the art).
Inner conductor 112 of first cable sub-assembly 104 may be fabricated from cooper or from any other suitable electrically conductive material. Additionally, inner conductor 112 may contain a conductive plating or the like. The conductive plating may be comprised of silver or other suitable material known in the art.
Cable 105 of first cable sub-assembly 104 may be long enough to allow a surgeon to extend it from electrosurgical energy generator “G” to the patient in a typical medical suite, while at the same time, short enough to limit energy attenuation therealong. Specifically, it is envisioned that the length of cable 105 may range from about 5 feet to about 10 feet. It is further contemplated that cable 105 may have a diameter greater than about 0.14 inches. In one embodiment, the diameter of cable 105 may measure approximately 0.20 inches.
In an alternative embodiment, cable 105 of first cable assembly 104 may be enclosed in an articulating arm that extends into and over the sterile field. The articulating arm may be part of the electrosurgical energy generator “G” or, a separate cart system. Alternatively, cable 105 may be detachably connected to the electrosurgical energy generator “G” via a fastening device such as a removable clip (not shown). The fastening device may prevent cable 105 from exerting excessive force on the energy delivering device “D”. Cable 105 and/or first cable sub-assembly 104 may be reusable or disposable.
Referring now to FIGS. 1 and 4, second cable sub-assembly 108 includes a cable 109 configured to transmit electrosurgical energy, a device connector 110 connected to a first end of cable 109 for connection to energy delivering device “D” and a second connector 106b of cable connector 106 operatively connected to a second end of cable 109 configured and adapted for selective coupling with first connector 106a of first cable sub-assembly 104. Device connector 110 may include adapters (not shown) to properly mate with energy delivering device “D” or second cable assembly 108.
With reference to FIG. 5, cable 109 of second cable sub-assembly 108 comprises an inner conductor 120 surrounded by a dielectric material 122, and an outer conductor 124 surrounding dielectric material 122 and encompassed by an outer sheath 126. Outer conductor 124 and inner conductor 120 are configured as a coaxial cable. Inner conductor 120 of second cable sub-assembly 108 has a smaller diameter than inner conductor 112 of first cable sub-assembly 104. Likewise, outer conductor 124 of second cable sub-assembly 108 has a smaller diameter than outer conductor 116 of first cable sub-assembly 104. Second cable sub-assembly 108 may be reusable or disposable.
It is envisioned that cable 109 of second cable sub-assembly 108 may be flexible. Accordingly, inner conductor thereof 120 may be flexible and may have a stranded transverse cross-sectional profile. Copper or other suitable electrically conductive material may be utilized to make inner conductor 120. In an embodiment, inner conductor 120 may include a silver plating.
The length of cable 109 of second cable assembly 108 may be short enough to limit energy attenuation, but sufficiently long to allow good maneuverability of energy delivering device “D”. It is envisioned that the length of cable 109 of second cable sub-assembly 108 may range from about 0.5 feet to about 2.0 feet. In one embodiment, the length of cable 109 of second cable sub-assembly 108 may measure about 12 inches. It is further contemplated that cable 109 of second cable sub-assembly 108 may have a diameter less than about 0.12 inches. In one embodiment, the diameter of cable 109 of second cable sub-assembly 108 may measure about 0.10 inches.
Dielectric material 122 of second cable sub-assembly 108 may be made of any suitable low loss dielectric material such as low density or ultra-low density PTFE, or cellular high density polyethylene. Outer conductor 124 of second cable sub-assembly 108 may be formed of braided silver plated cooper or any other suitable electrically conductive material known in the art.
In use, connectors 102, 106, 110 electrically connect electrosurgical energy generator “G”, first and second cable sub-assemblies 104, 108 of conduit assembly 100, and energy delivering device “D” to one another. To facilitate electrical conductivity throughout and along conduit assembly 100, connectors 102, 106, 110 may have an impedance appropriate for the specific electrosurgical system employed. It is envisioned that each connectors 102, 106, 110 may have an impedance of about 50 Ohms. In addition, an electrically insulative material, such as polylefin, PVC or plastic heat-shrink tubing, may be placed over connectors 102, 106, 110 to provide electrical insulation thereof, as illustrated in FIG. 2. A person skilled in the art will understand that many other kinds of suitable dielectric materials may be used to cover connectors 102, 106, 110.
Returning now to FIG. 2, the distal or first end of first cable sub-assembly 104 is connected to the proximal or second end of second cable sub-assembly 108 via first and second connectors 106a, 106b of cable connector 106. Adaptors may supplement cable connector 106 in the event that cable connector 106 does not properly mate with either first cable sub-assembly 104 or second cable sub-assembly 108. Alternatively, first cable sub-assembly 104 may be connected directly to second cable sub-assembly 108 through crimping, soldering, welding or any other suitable method as known by one skilled in the art. It will be apparent to one skilled in the art that second cable sub-assembly 108 may be connected to the energy delivering device “D” by any suitable method such as crimping, soldering, or welding.
In an alternative embodiment, the electrical connection between inner conductor 112 of first cable sub-assembly 104 and inner conductor 120 of second cable sub-assembly 108 may be achieved by crimping the inner conductor 120 over first inner conductor 112. If cable 105 of first cable sub-assembly 104 has a stranded inner conductor 112, electrical connection may be achieved by crimping the stranded inner conductor 112 over the inner conductor 120 of second cable sub-assembly 108. Electrical connection between outer conductors 116 of first cable sub-assembly 104 and outer conductor 124 of second cable sub-assembly 108 may be achieved by crimping first outer conductor 116 over second outer conductor 124, irrespective of their form.
In one embodiment, electrical connection between inner conductors 112, 120 may be achieved by soldering and/or welding the two inner conductors 112, 120 together. Outer conductors 116, 124 may also be soldered and/or welded together to achieve electrical connectivity therebetween. It is contemplated that a combination of crimping, soldering and welding may be used to connect inner conductors 112, 120 to one another and outer conductors 116, 124 to one another.
Conduit assembly 100 may have cable sub-assemblies having cables of various lengths with various energy attenuation levels. Alternatively, conduit assembly 100, having the same energy loss levels, may have cables of different sizes, diameters and/or lengths. It is envisioned that the conduit assembly 100 may have a maximum energy loss of about −3 dB at about 915 MHz.
In one embodiment, conduit cable assembly 100 may include first cable sub-assembly 104 having a cable 105 with a length of about 9 feet. Cable 105 is connected through cable connector 106 to a cable 109 of second cable sub-assembly 108 having a length of about 1 foot. Conduit cable assembly 100 also includes a generator connector 102 disposed at a proximal end thereof. As previously discussed, generator connector 102 is configured and adapted for connection to electrosurgical energy generator “G”. Generator connector 102 may include an insulative or dielectric covering 102a such as a polyolefin heat-shrink tubing. A device connector 110 is disposed at the distal end of the conduit assembly 100 and is configured and adapted for connection to electrosurgical energy delivery device “D”. Cable 105 may have an energy attenuation of about −0.14 dB/foot at about 915 MHz. In turn, cable 109 may have an energy attenuation of about −0.25 dB/foot at about 915 MHz. Each connector 102, 106, 110 may have an energy attenuation of about −0.07 dB at about 915 MHz. In this embodiment, the total energy attenuation at about 915 MHz may be about −1.79 dB. This embodiment may be used particularly for percutaneous applications.
In a further embodiment, conduit assembly 100 has a first cable sub-assembly 104 having a cable 105 with a length of about 6 feet. Cable 105 is connected through cable connector 106 to a cable 109 of second cable sub-assembly 108 having a length of about 1 foot. Conduit assembly 100 may have a generator connector 102 disposed at the proximal end thereof and a device connecter 110 disposed at the distal end thereof. Generator connector 102 is configured and adapted for connection to an electrosurgical energy generator “G”. Device connector 110 is configured and adapted for connection to an energy delivering device “D.” In this embodiment, cable 105 has an energy attenuation of about −0.14 dB/foot at about 915 MHz. Cable 109 has an energy attenuation of about −0.25 dB/foot at about 915 MHz. Each connector 102, 106, 110 may have an energy attenuation of about −0.07 dB at about 915 MHz. The total energy attenuation in this embodiment may be about −1.37 dB. This embodiment may be used particularly for surgical applications. While the figures of the present disclosure illustrate a conduit assembly 100 with only two cables, it is contemplated that more than two cables may be used to attain the desired combination of energy attenuation and assembly flexibility.
In use, first cable sub-assembly 104 allows transmission of electrosurgical energy from electrosurgical energy generator “G” to second cable sub-assembly 108. Cable connector 106 interconnects first cable sub-assembly 104 and second cable sub-assembly 108. To achieve low energy losses, the impedance of cable 105 of first cable sub-assembly 104 must be appropriate for the specific electrosurgical system used. For example, in one embodiment, first cable 105 of first cable sub-assembly 104 has an impedance of about 50 Ohms.
Moreover, cable 105 of second cable sub-assembly 108 has a higher degree of flexibility than cable 109 of first cable sub-assembly 104. However, cable 105 of first cable sub-assembly 108 has lower energy attenuation than cable 109 of second cable sub-assembly 104. Such a design provides conduit assembly 100 with good maneuverability, while at the same time, limits energy losses between electrosurgical energy generator “G” and energy delivering device “D”.
In operation, energy delivering device “D” is connected to electrosurgical energy generator “G” through conduit assembly 100 and receives electrosurgical energy from energy generator “G”. During operation, conduit assembly 100 minimizes the energy attenuation along its length, thereby maximizing the energy transmitted to energy delivering device “D”, and limiting heating of conduit assembly 100. Moreover, the flexibility of conduit assembly 100 allows a surgeon to easily maneuver energy delivering device “D” during clinical procedures.
Turning now to FIGS. 8 and 9, a conduit assembly according to another embodiment of the disclosure is generally designated as 200. Conduit assembly 200 is substantially similar to conduit assembly 100 and thus will only be discussed in detail herein to the extent necessary to identify differences in construction and operation.
As seen in FIGS. 8 and 9, conduit assembly 200 comprises a single cable 205 having a variable diameter along its length. Cable 205 includes a first or proximal section 204, a transition section 205a and a second or distal section 208. First section 204 has a diameter greater than a diameter of second section 208. Accordingly, a flexibility of second section 208 may be relatively higher than a flexibility of first section 204. In addition, first section 204 may have a relatively lower energy attenuation than second section 208.
Transition section 205a varies in diameter between first section 204 and second section 208. A proximal end of transition section 205a has a diameter equal to the diameter of first section 204. A distal end of transition section 205a has a diameter equal to the diameter of second section 208.
First section 204 is connectable to an electrosurgical energy generator “G” via a generator connector 202. Generator connector 202 may include an insulative or dielectric covering 202a such as a polyolefin heat-shrink tubing. Second section 208, in turn, is connectable to an energy delivering device “D” via device connector 210.
As seen in FIG. 9, cable 205 comprises an inner conductor 212 surrounded by a dielectric material 214, an outer conductor 216 surrounding dielectric material 214, and an outer sheath 218 encompassing outer conductor 216. Inner conductor 212 includes a first section 212a having a first diameter, a second section 212b having a second diameter, and transition section 212c interconnecting the first and second sections 212a, 212b. 
It is envisioned that cable 205 may be flexible or semi-rigid. Accordingly, inner conductor 212 of cable 205 may be flexible (i.e., having a stranded transverse cross-sectional profile or any other suitable flexible structure known in the art) or semi-rigid (i.e., having a solid transverse cross-sectional profile or any other semi-rigid structure known in the art). Cooper or other suitable electrically conductive material may be utilized to make inner conductor 212. Inner conductor 212 may also include silver plating. Outer conductor 216 may be flexible (i.e., made of braided silver plated cooper or any other suitable material known in the art) or semi-rigid (i.e., be fabricated of solid cooper or any other suitable material known in the art).
Dielectric material 214 may be formed of any suitable low energy loss material such as low density or ultra-density PolyTetraFluoroEthylene (“PTFE”), cellular high density polyethylene or the like. Outer sheath 218 may be comprised of any suitable electrically insulative material known in the art such as fluorinated ethylene propylene (“FEP”) or polyolefin. Conduit assembly 200 may have, for example, a total energy loss of about −1.79 dB or −1.37 dB.
Energy delivering device “D” may be used for surgical procedures entailing microwave ablation. However, the applications of the conduit assemblies and methods of using the conduit assemblies, discussed above, are not limited thereto, but may include any number of further electrosurgical applications. Modifications of the above-described conduit assembly and the same, and variations of aspects of the disclosure that are obvious to those of skill in the art are intended to be within the scope of the claims.

## Claims

1. A microwave cable assembly comprising:
a reusable cable configured to operatively couple to a microwave energy source; and
a disposable cable configured to operatively couple the reusable cable to a microwave antenna, wherein an energy attenuation of the reusable cable is different from an energy attenuation of the disposable cable.

2. The microwave cable assembly according to claim 1, wherein at least one of the reusable cable or the disposable cable includes an inner conductor and an outer conductor separated by a dielectric material.

3. The microwave cable assembly according to claim 1, wherein a diameter of the reusable cable is different from a diameter of the disposable cable.

4. The microwave cable assembly according to claim 1, wherein a length of the reusable cable is different from a length of the disposable cable.

5. The microwave cable assembly according to claim 1, wherein a flexibility of the reusable cable is different from a flexibility of the disposable cable.

6. The microwave cable assembly according to claim 1, further comprising a connector assembly configured to couple the disposable cable to the reusable cable.

7. The microwave cable assembly according to claim 2, further comprising an outer coating disposed about the outer conductor.

8. The microwave cable assembly according to claim 1, further comprising a connector assembly disposed on a proximal portion of the reusable cable.

9. A microwave cable assembly for transmitting microwave energy, the microwave cable assembly comprising:
a reusable cable portion including a first inner conductor and a first outer conductor separated by a first dielectric material, the reusable cable portion removably coupleable to a microwave energy source; and
a disposable cable portion including a first end and a second end, the first end removably coupleable to a second end of the reusable cable and the second end of the disposable cable removably coupleable to a microwave antenna, the disposable cable including a second inner conductor and a second outer conductor separated by a second dielectric material, wherein an energy attenuation of the reusable cable portion is different from an energy attenuation of the disposable cable portion.

10. The microwave cable assembly according to claim 9, further comprising a connector assembly disposed on the first end of the reusable cable portion.

11. The microwave cable assembly according to claim 9, wherein a flexibility of the reusable cable portion is different from a flexibility of the disposable cable portion.

12. The microwave cable assembly according to claim 9, wherein a diameter of the reusable cable portion is different from a diameter of the disposable cable portion.

13. The microwave cable assembly according to claim 9, wherein a length of the reusable cable portion is different from a length of the disposable cable portion.

14. The microwave cable assembly according to claim 9, further comprising a connector assembly configured to electrically couple the reusable cable portion to the disposable cable portion.