Surgery – Instruments – Electrical application
Reexamination Certificate
1999-06-23
2001-11-13
Peffley, Michael (Department: 3739)
Surgery
Instruments
Electrical application
C607S105000, C604S103010
Reexamination Certificate
active
06315776
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to an ablation apparatus for the selective ablation of the inner layers of body organs, and more particularly, to the endometrium layer of the uterus.
2. Description of Related Art
There are a number of body organs, including but not limited to the uterus, gall bladder, large intestine and the like, that have inner layers which have abnormal conditions. Traditional methods of treatment have included removal of the body organ to treat the, abnormal condition, the use of lasers, and the application of a thermal source.
A diseased condition of the uterus, menorrhagia, is defined as excessive menstrual bleeding in the absence of organic pathology. It has no known aetiology and it has been postulated that it is due to an inappropriate exposure of the endometrium to hormones. Menorrhagia is an exceedingly common problem, typically comprising approximately one in five outpatient referrals to gynecological departments. Women suffering severe menorrhagia are at risk from chronic anemia. The first treatment employed may be the administration of drug therapy. A major disadvantage is the need to administer drugs long term, and frequently the beneficial effects are only temporary. Another treatment is hysterectomy.
A number of physical and chemical methods have been tried as alternatives to hysterectomy, including the use of superheated steam, cryotherapy, urea injection and radium packing. The most commonly used methods as an alternative to hysterectomy are, ablation of the endometrium either by using a laser, such as a Nd:YAG laser, or the use of RF energy applied with an electrode.
Laser treatments have provided only limited success. RF is an attractive alternative. In RF heating, a conductive probe is placed within the uterine cavity and an insulated ground-plane electrode or belt is placed around the patient's midriff. RF energy is applied to the thermal probe with the external belt electrode acting as the return arm of the circuit. The electrical load presented by the RF thermal probe, patient, and external belt is matched to the output of the RF generator via a tuning unit, to form a series resonant circuit. Once tuned, the majority of the power applied to the probe is deposited into the endometrium as heat.
Current flows primarily capacitively, and an electric field is set up around the active tip of the probe. Tissue lying within the field becomes heated because of rapid oscillation of charged particles and locally induced currents.
Prior et al. have reported on the use of RF to treat menorrhagia. Power at 27.12 MHz was delivered to a probe that was placed into the uterine cavity and capacitively coupled to a second electrode consisting of a belt placed around the patient, Prior et al. , Int. J. Hyperthermia, 1991, Vol. 7, No. 2, pgs 213 to 220. The active electrode was a 10 mm diameter stainless-steel cylinder with a length of 70 mm. This method, however, did not adequately deliver RF energy to the entire endometrium. Because the endometrium has an irregular surface, it is difficult to deliver sufficient RF energy to the entire structure and effective treat menorrhagia.
However, it is desirable to have close contact between the RF conductive face and the endometrium. In U.S. Pat. No. 5,277,201 (the“'201 patent”) an electroconductive, expandable balloon expands the interior of the uterus and effects electrical contact with the endometrial lining to be destroyed. The device of the '201 patent fails, however, to provide sufficient physical contact with the entire endometrium, and thus the treatment is not complete. Not only is the physical contact with the endometrium unsatisfactory, but the effective delivery of RF energy to the endometrium could be improved.
There is a need for an RF ablation apparatus that provides more suitable conformation with a lining of a body organ, such as the endometrium of the uterus. Additionally, there is a need for an ablation device which provides controlled and selectable distributed energy to a selected tissue site, such as the endometrium.
SUMMARY OF THE INVENTION
An object of the invention is to provide an ablation apparatus suitable for interior thin walled areas of body organs.
Another object of the invention is to provide an ablation apparatus that effectively conforms to the shape of the interior of a body organ.
Yet another object of the invention is to provide an ablation apparatus that includes a flexible circuit.
Still a further object of the invention is to provide an ablation apparatus that includes an electrode positioned between first and second fluid conduits that surround an expandable member housing an electrolytic fluid.
Another object of the invention is to provide an ablation apparatus that includes a plurality of electrodes, each with an insulator surrounding a portion of the electrode, to provide for the selectable distribution of RF energy to a desired surface.
Yet another object of the invention is to provide an ablation apparatus that provides selectable delivery of RF energy to a tissue site, and includes a feedback device in response to a detected characteristic of the tissue site.
Still a further object of the invention is to provide an ablation apparatus that evenly distributes energy to the endometrium, and includes a feedback device to monitor impedance and temperature at the endometrium.
Another object of the invention is to provide an ablation apparatus that includes a feedback device for the selectable delivery of RF energy to the endometrium, and the impedance or a temperature profile of the endometrium is monitored.
A further object of the invention is to provide an ablation apparatus with a feedback device for the selectable delivery of RF energy, and the apparatus includes electrodes with insulators that are formed on a portion of each electrode for the even delivery of RF energy to a selected tissue site.
Still a further object of the invention is to provide an ablation apparatus that positions electrodes with insulators between two foam structures to provide for the selectable distribution of RF energy to a desired tissue site.
These and other objects are achieved with an ablation apparatus for ablating an inner layer of an organ in the body. An expandable member, including but limited to a balloon, has an exterior surface that includes a plurality of apertures. Housed within the expandable member is an electrolytic solution that is released through the apertures. A first fluid conduit includes a back surface that surrounds the exterior of the expandable member, and an opposing front surface. The first fluid conduit provides delivery of electrolytic solution from the expandable member. A second fluid conduit, with a conductive surface, has a back side that surrounds the first fluid conduit. The second conduit is made of a material that provides substantial conformity between the conductive surface and a shape of the inner layer of the organ. The second fluid conduit delivers electrolytic solution from the first fluid conduit to the inner layer. A plurality of electrodes is positioned between the first and second conduits. Each electrode includes an insulator formed on a surface of the electrode that is adjacent to the second fluid conduit.
By positioning the electrodes between the first and second fluid conduits, and insulating the side of the electrode or flexible circuit that is adjacent to the second conduit, energy delivery from the electrodes to the inner layer is selectable. It is selectable in that the energy can be distributed evenly over the target surface, and energy delivery can be variable, depending on the condition of the selected tissue site.
The electrodes can be positioned on a support member. Additionally, the electrodes can form a flexible circuit made of a plurality of segments. It can be a printed circuit, or a plurality of individual electrodes. The expandable member can be expanded within the interior of a selected organ mechanically, or by introducing a fluid, such as an electrolytic
Baker James
Edwards Stuart D
Lee Kee S
Strul Bruno
Glenn Michael A.
Peffley Michael
Vidacare, Inc.
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