Surgery – Miscellaneous – Methods
Reexamination Certificate
1998-09-09
2001-05-08
Isabella, David J. (Department: 3738)
Surgery
Miscellaneous
Methods
C604S891100, C607S003000, C607S046000
Reexamination Certificate
active
06227203
ABSTRACT:
1. Field of the Invention
This invention relates to neural tissue stimulation and drug therapy techniques, and more particularly relates to such techniques for treating movement disorders.
2. Description of Related Art
Patients with neurodegenerative diseases or trauma like cerebral infarct or spinal cord injury can have a variety of movement and muscle control problems, like resting, postural, intention or action tremor, dystonia (improper muscle tone); spasticity (undesirable movements, or muscle co-construction); dyskinesia (poorly executed movements) or involuntary movements like ballismus, choreiform movements and torticollis (inappropriate movements or limb control). Many of these problems can be called hyperkinesia. Although they can be chronic, or worse, progressive, they also may have times of relative remission. Such problems are found, at certain stages, for patients with Parkinson's disease (PD), multiple sclerosis, cerebral palsy, secondary to deafferentation pain, post stroke, post apoplexy or anoxia, post head or spinal trauma, post poisoning, cerebellar disease, etc.
Specifically with regard to PD, levodopa treatment has traditionally been the main medical treatment for PD. A major iatrogenic complication of levodopa treatment, however, is abnormal involuntary movements (AIMs). AIMs generally occur in PD patients treated for a long time with high doses of levodopa. Levodopa is believed to induce a dysfunction of dopaminergic receptors located in striatal neurons. The striatal neurons therefore respond in a disharmonious mama, namely by switching abruptly from being unresponsive receptors (phase off) to being hyper-responsive receptors (phase on).
This “phase off” is mainly characterized by a major hypokinesia or akinesia, which tends to immobilize the patient in a frozen state. The “phase on” is mainly characterized by a rapid recovery from the unfrozen state, allowing the patient to resume activity. This recovery from the unfrozen state, however, is accompanied by involuntary abnormal movements, appearing at various moments following the intake of levodopa.
AIMs are extremely disabling and may constitute by themselves a symptom which has to be cured to improve the patient. Treatment specifically directed to treating AIMs includes for example pallidotomy. Laitinen L. V., Bergenheim A. T., Hariz M. I., Leksell's Posteroventral Pallidotomy in the Treatment of Parkinson's Disease,
J. Neurosurg.,
76: 53-61, 1992. Although this technique, revived from that disclosed in Leksell Svenlinsonn et al., Treatment of Parkinsonism by Stereotactic Thermolesions in the Pallidal Region, A Clinical Evaluation of 81 Cases,
Acta Psychiatr. Neurol. Scand.,
35, 358-377, 1960), is efficient on the contalateral side and partially efficient on the homolateral side, it is not applicable to bilateral symptoms which might require a bilateral procedure. Bilateral procedures are usually followed by serious side effects such as neuropsychological deficits. To prevent these side effects, high frequency stimulation of the internal pallidum (GPi) has been employed, leading to subsequent significant improvement or even disappearance of AIMs.
Neuroscientsts now have a better understanding of the neural connections hat make up the basal ganglia. These connections are reviewed in Alexander, Crutcher, and DeLong, “Basal ganglia-thalamocortical circuits: parallel substrates for motor, oculomotor, “prefrontal” and “limbic” functions.
Prog. Brain Res.
85:119-146. The substantia nigra receives input from the subthalamic nucleus which is excitatory and involves glutamate as the neurotransmitter conveying information at the synapse. A lesion of the subthalamic nucleus will reduce the inhibitory output of the internal segment of the globus pallidus and substantia nigra reticulata. H. T. Bergman, T. Wichmann and M. R. DeLong, 1990,
Science,
249:1436-1438.
Stimulation of the Vim nucleus of the Thalamus will block tremor. Benabid et al.
The Lancet
, Vol 337: Feb 16, 1991, 403-406. In this instance, stimulation at frequencies around 100 to 185 pulses per second accomplishes the same physiological response as a lesion of this region of the brain. Benabid's research team has extended this work to stimulation of the subthalamus in order to help reduce symptoms of motion disorders. “VIM and STN stimulation in Parkinson's disease”,
Movement disorders
, Vol. 9, Supplement 1 (1994); “Effect on Parkinsonian signs and symptoms of bilateral subthalamic nucleus stimulation”,
The Lancet
, Vol 345, Jan. 14, 1995.
Although stimulation of STN (subthalamic nucleus) and VIM (ventral intermediate thalamus) do not control or reduce AIMs, researchers have observed that AIMs may be controlled by stimulation of the GPi.
SUMMARY OF THE INVENTION
A preferred form of the invention can treat a movement disorder resulting in abnormal motor response by means of an implantable pump and an implantable catheter having a proximal end coupled to the pump and a discharge portion to deliver one or more drugs to a portion of the brain. The invention includes an implantable signal generator and an implantable electrode having a proximal end coupled to the signal generator and having a stimulation portion for therapeutically stimulating the brain. The cathode and electrode are implantable in the brain so that the respective discharge and stimulation portions lie within or in communication with predetermined portions of the brain sufficient to block activity of the CM-Pf complex of the thalamus. The pump is operated to deliver drug at a predetermined rate and dosage and the signal generator is operated to provide electrical stimulation at a predetermined pulse width, frequency and amplitude. With blocked or reduced activity of the CM-Pf complex of the thalamus, excitation of the GPi by the subthalamic nucleus is thereby reduced. The reduction in excitation of the GPi in turn reduces the occurrence of Abnormal Involuntary Movement (AIM) disorders. By using the foregoing method, the occurrences of AIMs in persons with PD is reduced.
Another form of the invention uses one or more drugs or electrical stimulation to treat AIM disorders. In this embodiment, only the signal generator/electrode or pump/catheter portion is required. Alternatively, drug treatment may be performed with the use of encapsulated cells selected to secrete the appropriate substance or a drug eluting polymer. These encapsulated cells may be implanted into a predetermined treatment site in brain tissue. In one embodiment of the invention stimulation and/or infusion is carried out in a nearly continuous manner. In another form of the invention, the stimulation or infusion is initiated by the patient in response to abnormal involuntary movements.
Another form of the invention uses a sensor in combination with the stimulation and/or infusion techniques discussed above to treat AIM disorders. In this form of the invention, the sensor generates a sensor signal relating to the extent of the AIM disorder. Control means responsive to the sensor signal regulate the signal generator so that the stimulation is increased in response to an increase in the AIM disorder and is decreased in response to a decrease in the AIM disorder. Control means may also regulate the infusion of medicaments to affect the AIM disorder.
REFERENCES:
patent: 3850161 (1974-11-01), Liss
patent: 4146029 (1979-03-01), Ellinwood, Jr.
patent: 4692147 (1987-09-01), Duggan
patent: 4867164 (1989-09-01), Zabara
patent: 5025807 (1991-06-01), Zabara
patent: 5119832 (1992-06-01), Xavier
patent: 5293879 (1994-03-01), Vonk et al.
patent: 5423877 (1995-06-01), Mackey
patent: 5458631 (1995-10-01), Xavier
patent: 5711316 (1998-01-01), Elsberry et al.
patent: 5713923 (1998-02-01), Ward et al.
patent: 5716377 (1998-02-01), Rise et al.
patent: 5832932 (1998-11-01), Elsberry et al.
patent: 5833709 (1998-11-01), Rise et al.
patent: 5978702 (1999-11-01), Ward et al.
patent: 6018682 (2000-01-01), Rise
patent: 6094598 (2000-07-01), Elsberry et al.
patent: 940116 (1994-01-01), None
Raymond D. Adams, M.A.,
Benabid Alim
Caparros-Lefebvre Dominique
Rise Mark T.
Banner & Witcoff , Ltd.
Isabella David J.
Medtronic Inc.
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