WO2008131318A1

WO2008131318A1 - Radio frequency ablation device

Info

Publication number: WO2008131318A1
Application number: PCT/US2008/060961
Authority: WO
Inventors: Timothy Yeatman
Original assignee: University Of South Florida
Priority date: 2007-04-20
Filing date: 2008-04-21
Publication date: 2008-10-30

Abstract

The invention includes a tissue ablation device with curved needles providing a substantial technical advantage to the surgeon attempting to create a tract of ablation circumferentially around the entire tumor. The surgeon is able to preserve more healthy tissue, and needs to make few passes with the ablation device to effectively ablate around the entire tumor. The advantages create a more expeditious procedure. Reduction in the length of the surgery also results in lower risk to the patient.

Description

RADIO FREQUENCY ABLATION DEVICE

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to currently pending U.S. Provisional Patent Application 60/912,973, entitled, "Radiofrequency Ablation Device", filed April 20, 2007, the contents of which are herein incorporated by reference

FIELD OF INVENTION

The invention relates to surgical devices that utilize radiofrequency ablation to facilitate the removal of tissue. BACKGROUND OF INVENTION

There is a significant need for the development of improved alternatives to invasive surgical procedures in removing liver tumors. Radiofrequency ablation is such an alternative. It can also be used in patients with otherwise inoperable tumors.

The technique involves inserting a probe with protracting needles into the liver. Once in the liver, the needles are protracted and maneuvered to encompass the tumor. The needles then emit heat to destroy the surrounded tumor and the destroyed tissue is then absorbed as normal body waste. This alternative provides for much quicker recovery time, has few side effects, and is much less invasive than prior treatments.

The ablation device of the prior art, shown in FIG. 1 , is composed of an array of 4 straight needles (14a and 14b) connected to applicator head 12. As shown in FIG. 2, the needles create a one centimeter zone (26) of ablated liver (20). Ablation of the area around a tumor kills the cells surrounding the tumor and cauterizes it, creating a blood-free zone. After ablating, the surgeon cuts through the middle of the ablated tract in the blood-free zone.

The use of this technique reduces the loss of blood, the release of other bodily fluids, and the potential that a portion of the tumor will break off and redeposit in another location in the patient's body.

The problem with the existing device is that it has straight needles. The ablated area created by it is square or cubic. However, tumors are not square or cubic; rather they are spherical or elliptical and the liver surface is also curved. Creation of an ablated zone behind the tumor with the device of the prior art requires significant maneuvering of tissue by the surgeon.

SUMMARY OF INVENTION

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference should be made to the following detailed description, taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective representation of the prior art radiofrequency ablation device utilizing two rows of straight needles.

FIG. 2 is a block diagram showing the zone of ablated liver created by the prior art radiofrequency ablation device.

FIG. 3 is a perspective representation of one embodiment of the inventive radiofrequency ablation device utilizing two rows of curved needles.

FIG. 4 is a perspective representation of an alternate embodiment of the inventive radiofrequency ablation device utilizing one row of straight needles and one row of curved needles.

FIG. 5 is a block diagram showing the zone of ablated liver created by the inventive art radiofrequency ablation device utilizing one row of straight needles and one row of curved needles.

FIG. 6 is an alternate perspective view of the inventive radiofrequency ablation device utilizing two rows of curved needles.

FIG. 7a is a block diagram of one embodiment of the inventive radiofrequency ablation device utilizing two rows of four needles.

FIG. 7b is a block diagram of one embodiment of the inventive radiofrequency ablation device utilizing two rows of two needles. DETAILED DESCRIPTION OF THE PREFFERED EMBODIMENT

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part hereof, and within which are shown by way of illustration specific embodiments by which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the invention.

The current invention is an improvement upon an already existing radiofrequency ablation device. The ablation device of the prior art consists of a probe with two rows of straight needles, as illustrated in FIG. 1. Referring to FIG. 2, the straight needles (14b) of the prior art device force the shape of the area of the liver (20) that is ablated (26) during a procedure is cubic. However, tumors not cubic, but spherical or elliptical. As a result of the straight needle design of the prior art, the device destroyed more healthy tissue than necessary to facilitate removal of the tumor.

The current invention, shown in FIGS. 3 through 7b, includes a plurality of curved needles, as illustrated in FIGS. 3 and 4. It can be seen that the device can comprise needles which are all curved (FIG. 3) or combine curved needles (14) with straight needles (16) as shown in FIG. 4. Referring to FIG. 5, the curved needles (14a) enable the surgeon to surround the tumor (22) in closer proximity to its edges and thus destroy much less healthy tissue of liver 20. In one embodiment, the plurality of needles can range in number from four to eight. The arrangement of the needle attachment sites shown in the figures is in two columns. Each column may have any number of needles but the most common embodiments utilized two to four needle attachment sites per column. FIGS. 6 and 7b represent two columns (15a and 15b, FIG. 7b), each with two attachment sites. FIG. 7a represents two columns (15a and 15b), each with four attachment sites. Each of the plurality of needles is curved in a single plane. The plane of curvature of each of the needles can be parallel, as illustrated in FIGS. 3 and 4, or not parallel to the plane of another needle. The curvature and diameter of each needle can be constant along the length of the needle or vary along its length and can be different from the other needles. Values of the magnitude of curvature for a needle can vary from 0 cm^"1 to 5 cm^"1. FIG. 6 represents needles with a radius of curvature of about 0.15 cm^"1. The spacing between the needles at the point of insertion can vary from 0.5 cm to 1.5 cm. FIGS. 7a and 7B represent needles spaced at 1.0 cm apart along each of the x and y directions.

The length of each needle can be the same as or different from the length of another needle. The variance in length can range from 2 cm to 12 cm. A uniform needle length of 6 cm is illustrated in FIG. 6. The diameter of each needle can be constant along its length or can vary along its length and can vary from 0.1 mm to 4.0 mm. FIG. 6 represents needles with a uniform diameter of 1.0 mm. The end of the needle distal to the application head may be blunt or it may be tapered to a point. The variations in the needles provide options to the surgeon to complement the size, shape, and location of the tumor to further reduce the amount of healthy tissue destroyed. It will be seen that the advantages set forth above, and those made apparent from the foregoing description, are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall there between. Now that the invention has been described,

Claims

What is claimed is:

1. A tissue ablation device, comprising: an applicator head; a plurality of elongate needles connected to the applicator head at a first end; wherein at least one of the plurality of elongate needles is inwardly curved along a single plane.

2. The tissue ablation device of claim 1 , wherein the plane of curvature of at least one elongate electrode element is substantially parallel to the plane of curvature of at least one other elongate needle.

3. The tissue ablation device of claim 1 magnitude of curvature of at least one of the plurality of elongate needles is uniform along its length.

4. The tissue ablation device of claim 1 magnitude of curvature of at least one of the plurality of elongate needles varies along its length.

5. The tissue ablation device of claim 1 wherein the magnitude of curvature of at least one of the plurality of elongate needles is between about 0 cm^"1 and 5 cm^"1. 6. The tissue ablation device of claim 6, wherein the device comprises between about 4 and 8 elongate needles.

7. The tissue ablation device of claim 1 , wherein the plurality of elongate needles are arranged in two, substantially parallel, rows.

8. The tissue ablation device of claim 1 , wherein the plurality of elongate needles is spaced from each other at the point of connection to the applicator head.

9. The tissue ablation device of claim 8, wherein the spacing between the plurality of elongate needles is between about 0.5 cm and 1.5 cm.

10. The tissue ablation device of claim 1 , wherein the length of at least one of the plurality of elongate needles is the same as that of another of the plurality of elongate needles.

1 1. The tissue ablation device of claim 1 , wherein the length of at least one of the plurality of elongate needles differs from that of another of the plurality of elongate needles.

12. The tissue ablation device of claim 1 , wherein the length of at least one of the plurality of elongate needles is between about 2 cm and 12 cm. 13. The tissue ablation device of claim 1 , wherein the diameter of at least one of the plurality of elongate needles is constant along its length of the needle.

14. The tissue ablation device of claim 1 , wherein the diameter of at least one of the plurality of elongate needles varies along its length of the needle.

15. The tissue ablation device of claim 1 , wherein the diameter of at least one of the plurality of elongate needles is between about 0.1 mm and 4.0 mm.

16. The tissue ablation device of claim 1 , wherein the second of at least one of the plurality of elongate needles is blunt.

7. The tissue ablation device of claim 1 , wherein the second of at least one of the plurality of elongate needles is tapered.