Abstract:
A method and apparatus for introducing a medicinal dose directly into a mammalian patient&#39;s cerebrospinal fluid. One embodiment of the present invention comprises implanting a first and second device in a mammalian patient to administer the medicinal dose. The first device comprises a ventricular catheter, a reservoir with a built-in one-way valve, and a drug port with pump, wherein the three components are in fluid communication. The second device comprises a drug port-catheter system in fluid contact with lumbar sub-arachnoid space.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    Embodiments of the present invention generally relate to therapeutic mechanisms for treating brain disorders, and more particularly, to a method and apparatus for introducing a medical dose directly into a mammalian patient&#39;s cerebrospinal fluid. 
         [0003]    2. Description of the Related Art 
         [0004]    Most drugs that are designed to treat brain diseases, such as Alzheimer&#39;s Disease (AD), encounter the difficulty of getting across the Blood-Brain-Barrier (BBB). The Blood-Brain-Barrier is the body&#39;s natural central nervous system defense mechanism. The Blood-Brain-Barrier is very effective in restricting the movement of certain molecules to the brain. Therefore, infections of the brain are quite rare. However, this same effective protection makes the treatment of brain infections or diseases that do occur very difficult. That is, the Blood-Brain-Barrier prevents therapeutic drugs that may be introduced into the blood stream from reaching the brain in the same manner in which harmful substances or infections are prevented from reaching the brain. Hence, drugs targeting brain diseases are typically administered to a patient in higher doses than what is actually needed to remedy the diseases. Thus, only a fraction of a systemic or intravenous (IV) dose of a drug targeting a brain disease would be required if the drug could be introduced directly into the cerebrospinal fluid (CSF) that is in and around a patient&#39;s brain and spine. 
         [0005]    Accordingly, there exists the need for a method to overcome or circumvent the body&#39;s natural central nervous system defense mechanism to efficiently administer drugs or other therapeutic substances to the brain for the treatment of various brain diseases or infections. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention generally relates to a method and apparatus for introducing a medicinal dose directly into a mammalian patient&#39;s cerebrospinal fluid. One embodiment of the present invention comprises implanting a first device and second device in a mammalian patient. The first device comprises a ventricular catheter, where the catheter is in fluid contact with the lateral ventricle of the patient; a reservoir with a built-in one-way valve, wherein the reservoir is implanted subcutaneously under the scalp; and a drug port with pump, wherein the three components are in fluid communication. The second device comprises a drug port-catheter system in fluid contact with lumbar sub-arachnoid space; filling the drug port with a medicinal dose; waiting for a therapeutically sufficient period of time for the medicinal dose to take affect; removing cerebrospinal fluid from the lumbar sub-arachnoid space through the port-catheter system; infusing a fluid that mimics cerebrospinal fluid in an amount about equal to the amount removed through the subcutaneous reservoir to avoid a significant reduction in intracranial pressure; and accessing and refilling the drug port with the medicinal dose when another medicinal dose is required. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0008]      FIG. 1  is a drawing of a subcutaneous reservoir and ventricular catheter system that depicts certain aspects of various embodiments of the present invention. 
           [0009]      FIG. 2  is a drawing of a subcutaneous reservoir and lumbar catheter system that depicts certain aspects of various embodiments of the present invention. 
           [0010]      FIG. 3  is a drawing of a subcutaneous reservoir, drug pump system, and lumbar catheter system that depicts certain aspects of various embodiments of the present invention. 
       
    
    
       [0011]    While the invention is described herein by way of example using several embodiments and illustrative drawings, those skilled in the art will recognize that the invention is not limited to the embodiments of drawing or drawings described. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modification, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include,” “including,” and “includes” mean including, but not limited to. Further, the word “a” means at least one. 
       DETAILED DESCRIPTION 
       [0012]      FIG. 1  is a drawing of a subcutaneous reservoir and ventricular catheter system that depicts certain aspects of various embodiments of the present invention. 
         [0013]    As shown in  FIG. 1 , reservoir  104  is depicted implanted under a patient&#39;s scalp. Thus, the reservoir is labeled subcutaneous reservoir  104 . One end of ventricular catheter  102  is in fluid contact the subcutaneous reservoir. The other end of the ventricular catheter is in fluid contact with the lateral ventricle of the patient&#39;s brain. Hence the lateral ventricle of the patient&#39;s brain is in fluid communication with the subcutaneous reservoir. 
         [0014]    According to one embodiment of the present invention, subcutaneous reservoir  104  may be injected with a medicinal dose of an AD drug (e.g., NeuroChems&#39;s Alzhemed™, as reported in “7 ways to Save a Brain”, Newsweek Special Issue, 2005) that attracts harmful protein (e.g., A-Beta and Tau). The drug may be injected through the patient&#39;s scalp into the subcutaneous reservoir using, for example, a needle and syringe. The drug, then, may be infused through the ventricular catheter into the lateral ventricle of the brain and thus directly into the cerebrospinal fluid. Because the medicinal dose is administered in the manner described, circumventing the blood-brain-barrier, the dose amount may be reduced to a level appropriate for treating a targeted disease or brain disorder. There would be no need for a larger dose amount as would be required when the drug has to overcome the blood-brain-barrier to effectuate treatment. 
         [0015]      FIG. 2  is a drawing of a subcutaneous reservoir and lumbar catheter system that depicts certain aspects of various embodiments of the present invention. 
         [0016]    As shown in  FIG. 2 , reservoir  204  is implanted under a patient&#39;s scalp. The reservoir is depicted equipped with two chambers. At one end, dual lumen catheter  202  is in fluid contact with the dual chamber reservoir. A first lumen of the dual lumen catheter is in fluid contact with a first chamber of the dual chamber reservoir. A second lumen of the dual lumen catheter is in fluid contact with the second chamber of the dual chamber reservoir. The other end of the dual lumen catheter is in fluid contact with the lateral ventricle of the patient&#39;s brain. Thus the lateral ventricle is in fluid communication with the dual chamber reservoir. Alternately (not shown), two single lumen catheters may be utilized instead of the dual lumen catheter. The dual or single lumen catheter may be comprised of a silicone elastomer. 
         [0017]    According another embodiment of the present invention, the first chamber of subcutaneous reservoir  204  may be injected with a medicinal dose of an AD drug (e.g., NeuroChems&#39;s Alzhemed™, reported in “7 ways to Save a Brain”, Newsweek Special Issue, 2005) that attracts harmful protein (e.g., A-Beta and Tau) or enzyme that eats/digests A-Beta and/or other harmful proteins. The drug may be injected through the patient&#39;s scalp into the first chamber of the subcutaneous reservoir using, for example, a needle and syringe. The drug, then, may be infused through the first lumen of the dual lumen catheter into the lateral ventricle of the brain and thus directly into the cerebrospinal fluid. 
         [0018]    After a therapeutically sufficient period of time for the medicinal dose to take effect has elapsed, cerebrospinal fluid may be removed through the second chamber of the dual chamber reservoir via the second lumen of the dual lumen catheter. Drugs such as Alzhemed™ are designed to attract harmful proteins (e.g., A-Beta and Tau). By using such drugs in the manner just described, the deposit of harmful proteins into a patient&#39;s brain tissue may be avoided. Also again, administering drugs across or behind the blood-brain-brain barrier as just described reduces the amount of a medicinal dose required to therapeutically treat a targeted brain disorder. 
         [0019]    Alternate to removing cerebrospinal fluid through a second chamber of a dual chamber reservoir (e.g., dual chamber reservoir  204 ) some embodiments of the present invention comprises, instead, removing cerebrospinal fluid from a patient&#39;s lumbar subarachnoid space through an implanted lumbar catheter and reservoir system which is in fluid contact with the patient&#39;s lumbar subarachnoid space (e.g., lumbar catheter and reservoir system  206 ). 
         [0020]    In accordance with various embodiments of the present invention, the removed cerebrospinal fluid may be replaced via the first chamber of dual chamber reservoir (e.g., dual chamber reservoir  204 ) with normal saline or a fluid that mimics cerebrospinal fluid. By replacing the removed cerebrospinal fluid, a significant drop in the patient intra-cranial pressure can be avoided. 
         [0021]      FIG. 3  is a drawing of a subcutaneous reservoir, drug pump system, and lumbar catheter system that depicts certain aspects of various embodiments of the present invention. 
         [0022]    As shown in  FIG. 3 , reservoir  304  is implanted under a patient&#39;s scalp. The reservoir is depicted equipped with a one-way valve. At one end, catheter  306  is in fluid contact with reservoir  304 . At the other end catheter  306  is in fluid contact with drug pump  308 . Additionally, one end of ventricular catheter  302  is also in fluid contact with reservoir  304 . The other end of ventricular catheter  302  is in fluid contact with the lateral ventricle of the patient&#39;s brain. Consequently, the drug pump system is in fluid communication with the patient&#39;s lateral ventricle. 
         [0023]    According to yet another embodiment of the present invention, a medicinal dose of an AD drug may be injected into drug pump system  308 . The drug may then be infused by the pump system through reservoir  304  to the lateral ventricle via ventricle catheter  302  and thus directly into the cerebrospinal fluid. 
         [0024]    As with various other embodiments of the present invention, cerebrospinal fluid may be removed from the patient&#39;s lumbar subarachnoid space through an implanted lumbar catheter and reservoir system which is in fluid contact with the patient&#39;s lumbar subarachnoid space (e.g., port with lumbar catheter system  310 ). Again, such removal of cerebrospinal fluid is undertaken after a therapeutically sufficient period of time for the medicinal dose to take effect has elapsed. 
         [0025]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.