Catheter and guide tube for intracerebral application

Abstract

A catheter for use in neurosurgery, and a method of positioning neurosurgical apparatus. The catheter has a fine tube arranged for insertion into the brain parenchyma of a patient with an external diameter of not more than 1.0 mm. The catheter and method may be used in stereotactically targeting treatment of abnormalities of brain function, and for the infusion of therapeutic agents directly into the brain parenchyma. This is advantageous when a therapeutic agent would have widespread unwanted effects which could be avoided by confining the delivery to the malfunctioning or damaged brain tissue.

1 . A method for delivering a therapeutic agent to a desired target in the brain of a subject, the method comprising the steps of:
 inserting a neurosurgical catheter comprising a fine tube with an external diameter of not more than 1.0 mm into the brain parenchyma of a patient; and   intermittently pumping a therapeutic agent through the catheter to the desired target.   
     
     
         2 . A method according to  claim 1 , wherein the therapeutic agent comprises a neurotrophic factor. 
     
     
         3 . A method according to  claim 2 , wherein the neurotrophic factor is delivered to treat at least one of Parkinson's disease, Alzheimer's disease and multiple sclerosis. 
     
     
         4 . A method according to  claim 2 , wherein the neurotrophic factor is delivered to treat stroke or a brain injury. 
     
     
         5 . A method according to  claim 2 , wherein the neurotrophic factor comprises recombinant-methionyl human glial cell line derived neurotrophic factor (r-met Hu GDNF). 
     
     
         6 . A method according to  claim 1 , wherein the therapeutic agent comprises at least one of a Gamma-amino-butyric-acid, an opiate or an analgesic. 
     
     
         7 . A method according to  claim 1 , wherein the therapeutic agent comprises a cytotoxic agent and the desired target in the brain comprises a brain tumour. 
     
     
         8 . A method according to  claim 1 , further comprising a step of identifying the desired target from diagnostic images of the patient. 
     
     
         9 . A method according to  claim 1 , wherein the step of inserting a neurosurgical catheter comprises the steps of forming a hole in the skull of the subject and stereotactically guiding the catheter to the desired target. 
     
     
         10 . A method according to  claim 1 , wherein the desired target is located within at least one of a mesencephalon, a subthalamic nucleus, a nucleus basalis, a substantia nigra, a pedunculopontine nucleus, a brain stem, a peri-aqueductal grey matter and a thalamic nucleus. 
     
     
         11 . A method according to  claim 1 , further comprising a step of securing the catheter to the skull of the subject after insertion. 
     
     
         12 . A method according to  claim 1 , wherein the step of intermittently pumping a therapeutic agent through the catheter to the desired target in the brain comprises a step of chronically infusing therapeutic agent to the desired target in the brain. 
     
     
         13 . A method according to  claim 1 , wherein the step of intermittently pumping a therapeutic agent through the catheter to the desired target comprises the step of pumping therapeutic agent through the catheter at, during periods of infusion, a flow rate of between 2 and 8 micro-litres per hour. 
     
     
         14 . A method according to  claim 1 , further comprising a step of implanting a pump, a reservoir and tubing into the subject, wherein the pump, the reservoir and the tubing are used to intermittently pump the therapeutic agent to the catheter. 
     
     
         15 . A method according to  claim 1 , wherein the step of intermittently pumping a therapeutic agent through the catheter to the desired target comprises the step of using a peristaltic pump. 
     
     
         16 . A method according to  claim 1 , wherein the fine tube has an external diameter of not more than 0.7 mm. 
     
     
         17 . A method according to  claim 1 , wherein the fine tube has an external diameter of not more than 0.65 mm. 
     
     
         18 . A method according to  claim 1 , wherein the fine tube has an external diameter of not more than 0.5 mm. 
     
     
         19 . A method according to  claim 1 , wherein the fine tube is constructed from polyurethane plastic. 
     
     
         20 . A method according to  claim 1 , wherein the step of inserting a neurosurgical catheter comprises the step of inserting the fine tube of the neurosurgical catheter into the brain parenchyma through a previously inserted guide tube.