Surgery – Instruments – Electrical application
Reexamination Certificate
1999-06-04
2001-04-24
Cohen, Lee (Department: 3739)
Surgery
Instruments
Electrical application
C607S099000, C607S113000
Reexamination Certificate
active
06221071
ABSTRACT:
TECHNICAL FIELD
The invention relates generally to apparatus and methods for tissue ablation. More particularly, the invention relates to the rapid deployment of an everted array of electrodes used to ablate tissue.
BACKGROUND INFORMATION
Many of the current procedures for the treatment of cancer are disruptive and cause damage to healthy tissue. Two such procedures include resection of the tumor and hyperthermia treatment of the tumor. In a resection procedure, the physician must be careful not to cut the tumor in a manner that creates seeding of the tumor and thereby results in metastasis. In a hyperthermia procedure, the extent of localization of the heat is generally poor, resulting in damage to healthy tissue in the vicinity of the treatment site.
Ablation of cellular tissues in situ is used to treat cancer in a manner that ideally minimizes both the potential for damage to healthy tissue and for seeding of the tumor cells. Ablative procedures deliver electromagnetic energy directly to the tumor cells so as to necrose the tumor cells. The tumor cells are not cut, so the incidence of seeding is eliminated. Furthermore, the use of electromagnetic energy can be advantageous, because it can be rapidly dissipated and therefore can reduce the incidence of damage to healthy tissue surrounding the treatment site.
One such electromagnetic energy for use in ablation of tumor cells is radio frequency, or RF, energy. In typical RF ablation procedures, however, it is difficult to position the ablation electrodes so as to ablate effectively the entire tumor mass without resorting to multiple procedures.
SUMMARY OF THE INVENTION
An everted array of ablation electrodes can be used in an attempt to ablate effectively the largest possible volume of tissue mass during each ablation procedure. U.S. Pat. No. 5,827,279, which is hereby incorporated by reference herein, relates to this type of electrode array. Such everted arrays of electrodes can be difficult to deploy accurately and uniformly into tissue. The individual electrodes of the array can become bent or twisted as they enter the tissue and therefore do not develop a uniform shape. Without this uniform shape, the largest possible volume of the tumor is typically not treated during each procedure. Additionally, such everted arrays may not deploy accurately in that the electrodes can push against the tumor and move it, rather than penetrate it.
It is an object of the invention to reduce the difficulties associated with accurate and uniform deployment of an everted array of electrodes into tissue for the ablation of tumors. It is another object of the invention to provide an apparatus for tissue ablation that includes an electrode actuator to advance rapidly electrodes into tissue so that they assume an outwardly everted configuration within the tissue and thereby increase the volume of tissue treated by the electrodes in a single ablation procedure. An outwardly everted configuration is intended to include a configuration of the electrode array in which substantially all of the individual electrodes of the at least two electrodes in the array extend from the distal end of the elongate member and curve back toward the elongate member without otherwise bending or twisting.
The invention relates to an apparatus for tissue ablation which comprises an elongate member, at least two electrodes, and an electrode actuator. The elongate member has a proximal end, a distal end, and a lumen. The electrodes are housed within the lumen of the elongate member, and the electrodes are advanceable beyond the distal end of the elongate member and into tissue to a target site. The electrode actuator operates to advance rapidly the electrodes beyond the distal end of the elongate member and into tissue to the target site. The rapid advancement of the electrodes prevents the electrodes from bending or twisting as they enter the tissue, thereby allowing them to assume an outwardly everted configuration as they are advanced into the tissue.
The external surface of the elongate member can be at least partially insulated by, for example, being covered with an insulating material. Alternatively, all but the distal end of the external surface of the elongate member can be covered with an insulating material. In another embodiment, the distal end of the elongate member comprises a sharpened tip for penetrating tissue. In some embodiments in which the elongate member has a sharpened tip, the tissue ablation apparatus can further comprise an elongate member actuator, which operates to advance rapidly the elongate member so that the sharpened tip penetrates tissue at the target site.
The electrodes may be needle electrodes. The electrodes may also be at least partially covered with an insulating material. In one embodiment, the electrodes are hollow needle electrodes in communication with a fluid reservoir for delivering a fluid to the target site. After advancement of the electrodes beyond the distal end of the elongate member, the electrodes may be retracted back into the lumen of the elongate member. In one embodiment of the invention, the electrodes are in electrical communication with a source of RF energy and deliver RF energy to the target site so as to ablate tissue at the target site. In another embodiment, the electrodes are in electrical communication with an impedance monitor for monitoring an impedance of tissue at the target site.
An electrode actuator for use in an apparatus of the invention may be any device capable of exerting a force on the electrodes so as to advance rapidly the electrodes beyond the distal end of the elongate member and into tissue while assuming a uniform outwardly everted configuration. The electrode actuator may comprise a spring or a pneumatic cylinder, such as a carbon dioxide (CO
2
) cylinder. Additionally, an elongate member actuator according to the invention may be any device capable of exerting a force on the elongate member so as to advance rapidly a sharpened tip of the elongate member into tissue at a target site. The elongate member actuator may comprise a spring, for example.
Methods of the invention relate to the use of an apparatus, such as the above-described apparatus, to ablate tissue. In some embodiments, the sharpened distal tip of the elongate member is used to advance, rapidly or not, the tip of the apparatus to the target site. The target site within tissue generally is the site of a tumor or any other tissue mass targeted for ablation. The electrodes are then rapidly advanced into the tissue to the target site so that they assume an outwardly everted configuration, as described above. The tissue at the target site is then ablated (by, for example, delivering RF energy to the target site via the electrodes). The impedance of tissue at the target site can be monitored and fluid can be delivered to the target site. The measured impedance and the delivery of fluid can be used either separately or together to control the course of the ablation and to achieve the desired result.
The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.
REFERENCES:
patent: 4989614 (1991-02-01), Dejter et al.
patent: 5361760 (1994-11-01), Normann et al.
patent: 5368045 (1994-11-01), Clement et al.
patent: 5526822 (1996-06-01), Burbank et al.
patent: 5649547 (1997-07-01), Ritchart et al.
patent: 5667488 (1997-09-01), Lundquist et al.
patent: 5769086 (1998-06-01), Ritchart et al.
patent: 5775333 (1998-07-01), Burbank et al.
patent: 5794626 (1998-08-01), Kieturakis
patent: 5803912 (1998-09-01), Siczek et al.
patent: 5827276 (1998-10-01), LeVeen et al.
patent: 5836906 (1998-11-01), Edwards
patent: 5980517 (1999-11-01), Gough
patent: 6050992 (2000-04-01), Nichols
patent: 6053937 (2000-04-01), Edwards et al.
patent: 6071280 (2000-06-01), Edwards et al.
patent: 2323283A (1998-09-01), None
patent: WO92/10142 (1992-06-01), None
patent: WO96/29946 (1996-10-01), None
patent: WO98/06334 (1998-02-01), None
patent: WO98/49943 (1998-11-01),
Hoffman Keith
Sherry John
Cohen Lee
Sci-Med Life Systems, Inc.
Testa Hurwitz & Thibeault LLP
LandOfFree
Rapid electrode deployment does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rapid electrode deployment, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rapid electrode deployment will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2465276