Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Thermal applicators
Reexamination Certificate
2001-07-13
2003-10-07
Gibson, Roy D. (Department: 3739)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Thermal applicators
C607S096000, C607S099000
Reexamination Certificate
active
06629990
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to treatment of movement disorders and, more particularly, to intracranial treatment utilizing identification of an incipient movement disorder.
BACKGROUND OF THE INVENTION
Movement disorders such as epilepsy and Parkinson's disease have been estimated to affect some 1-2% of the developed world's population and up to 10% of people in underdeveloped countries. Currently, approximately 75% of those who suffer from movement disorders are responsive in some degree to drugs. However, undesirable side effects often prevent such treatment.
In addition, drug treatment often imposes a continual effect on brain cells and other tissues commonly resulting in the perpetual presence of side effects, while the movement disorder episodes, e.g., epileptic seizures, sought to be prevented occur much less frequently. Furthermore, patients often develop such high tolerances for the drugs administered that they are no longer effective at safe dosages. Therefore, there has been a need for movement disorder suppression which avoids the use of drugs.
Electrical stimulation has been utilized to treat some movement disorders. In the treatment of epilepsy, studies have been performed in which awake patients undergoing temporal lobe surgery underwent cortical stimulation. Such stimulation of the visual and hearing areas of the brain reproducibly caused the patients to experience visual and auditory phenomena. This discovery was made possible by the identification that certain brain subregions served specific functions, such as sight, hearing, touch and movement of the extremities and proved that direct electrical stimulation of the brain regions could cause partial reproduction or suppression of the functions.
As suggested by these results, it is known that certain types of treatment of specific portions of the brain are able to suppress certain unwanted behavior which results from movement disorders. This behavior may include seizures such as those suffered by epileptics. However, the studies faced a major problem in that there was an inability to precisely electrically stimulate very small volumes of the brain.
The advent of needle-shaped penetrating depth electrodes helped to overcome this obstacle faced by electrical stimulation. Depth electrodes can be placed within the brain tissue itself, enabling optimal surface contact with elements of the brain that are targeted for stimulation. This allowed for safe, chronic electrical stimulation of very small discrete volumes of brain.
There have been attempts to provide neurocybernetic prostheses for alleviating epilepsy and related disorders. U.S. Pat. No. 4,702,254 to Zabara discloses a prosthesis which comprises a miniature electronic integrated circuit with an output which augments appropriate brain neural discharge to control convulsions or seizures. The Zabara device uses neural spectral discrimination by tuning the electrical current of the prosthesis to the electrochemical properties of a specific group of inhibitory nerves that affect the reticular system of the brain. Certain electrical parameters of the prosthesis must be selected based on the electrochemical properties of the nerves desired to be activated. The patent teaches that the optimal site for the application of the prosthesis is on the vagus nerve.
While the electrical stimulation of brain tissue has been somewhat effective in the treatment of migraines, epilepsy and other neurological problems, patients often experience diminishing returns with such treatment. Furthermore, because each patient reacts differently to electrical stimulation, substantial time must be spent to determine the specific amplitude, frequency, pulse width, stimulation duration, etc. which may result in effective treatment. In addition, such parameters often require continual adjustment in order to remain effective.
In treatment, electrical stimulation has been used with the recording and analysis of electrical changes in brain activity to predict the occurrence of epileptic seizures. The time of onset of such seizures is often predictable by neural discharge monitoring, even when the exact causal nature of precipitating dysfunction is not understood. U.S. Pat. No. 5,995,868 to Dorfmeister discloses the use of electrodes to obtain signals representative of current brain activity and a signal processor for continuous monitoring and analysis of these electrical signals in order to identify important changes or the appearance of precursors predictive of an impending change. Dorfmeister mainly discusses the quick identification of the onset of a seizure; cooling a portion of the brain in response to such identification is mentioned, but he does not discuss how such cooling could be performed.
At the time of Dorfmeister, the treatment of various disorders of and injuries to the brain utilizing the transfer of heat away from (cooling) the brain was well known in the medical arts and was often performed using the external application of cold fluids, housed chemicals involved in endothermic reactions or other refrigerants. Other methods of cooling include the external cooling of blood which is recirculated through the body.
U.S. Pat. Nos. 4,750,493 and 4,920,963 to Brader are directed to a method for cooling the extracranial area during emergency care of cardiac arrest or extreme shock in order to induce vasoconstriction and intracranial hypothermia. These inventions are implemented by a topical cold pack or watertight shroud which cannot specifically cool a targeted portion in the brain. U.S. Pat. No. 5,383,854 to Safar et al. is directed to a cardiopulmonary bypass apparatus which is able to cool the blood. This device cannot specifically cool a target portion in the brain either.
U.S. Pat. No. 6,188,930 B1 to Carson is directed to a method for heating the hypothalamus which utilizes a device for cooling the surrounding body tissues. This device is not implanted, but is used temporarily during or preceding surgery. The patent discloses cooling through the circulation of a liquid or gas coolant through a catheter. Chronic cooling of a targeted portion in the brain is not disclosed.
U.S. Pat. No. 6,090,132 to Fox is directed to a method of inducing hypothermia in a mammal. This invention applies heat to the hypothalamus in order to effect a compensatory cooling response, thereby lowering body temperature. The patent discloses the direct application of heat to the hypothalamus for a temporary cooling effect. The patent does not disclose chronic treatment using an implanted device, nor the cooling of a specific portion.
U.S. Pat. No. 5,215,086 to Terry employs a neurostimulator to selectively apply electrical therapy to treat migraines. The neurostimulator delivers pulses of electricity of a specific pulse width and amplitude to the patient's vagus nerve in order to stimulate nerve fibers and either synchronize or desynchronize the EEG and control migraines.
U.S. Pat. Nos. 5,843,093 and 6,129,685 to Howard relate to the selective treatment of neurons within the brain with particular emphasis on the treatment of Parkinson's through pallidotomy and on the regulation of a patient's appetite through electrical discharges to the hypothalamus. Both of these patents disclose the inactivation of neurons through the use of a cryogenic device, though they do not teach what the cryogenic device could be or how it might be safely disposed within the brain.
Despite the Dorfmeister and Howard disclosures, it has not yet been possible, upon recognition of an incipient movement disorder, to effectively and immediately cool a localized area in the brain with an implanted device episode which can avoid undue risk or injury to the brain. An implanted device for thermal treatment of movement disorders episodes which addresses the problems of known treatments would be an important advance in the art.
OBJECTS OF THE INVENTION
It is an object of the invention to provide an implanted device for thermal treatment of movement disorders overcoming some of the problems an
Putz David A.
Ziobro John
Ad-Tech Medical Instrument Corp.
Gibson Roy D.
Jansson & Shupe & Munger Ltd.
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