Device and method for delivering therapeutic agents to an area of the body

Abstract

A device, system and method deliver an agent to a soft mass, such as an area of the body, and more specifically the brain. One aspect includes creation of one or more channels, tunnels or grooves in tissue using a relatively small diameter, minimally-invasive stylet and then removing the stylet prior to infusion. The stylet-created channels become paths of increased hydraulic conductivity, through which the infusate will tend to flow and produce a predictable infusion pattern. Infusate will be carried into these channels with relatively low resistance, and then infuse outward from these channels into the surrounding tissue. By carefully positioning these channels, one can control and modify the preferred paths and duration of distribution.

1 ) A method of delivering a substance to a region of the body comprising:
 inserting a tissue-penetrating device into tissue,   removing the tissue penetrating device, thereby creating a channel in the tissue, and   delivering the substance into that channel.   
     
     
         2 ) The method of  claim 1  wherein the device comprises a stylet or obturator carried to the tissue by a cannula or catheter. 
     
     
         3 ) The method of  claim 2  wherein after the stylet penetrates the tissue, drug is delivered in a region about the channel formed by the penetration of the stylet. 
     
     
         4 ) The method of  claim 3  wherein the drug is delivered while the stylet is at its deepest penetration into the tissue. 
     
     
         5 ) The method of  claim 3  wherein the drug is delivered while the stylet is being withdrawn or has been partially withdrawn from its deepest penetration into the tissue. 
     
     
         6 ) The method of  claim 3  wherein the drug is delivered after the stylet has been completely withdrawn from its deepest penetration into the tissue. 
     
     
         7 ) The method of  claim 1  wherein at least one channel is created by extending a stylet or obturator at least some distance exterior to a cannula that is coaxial with the cannula and coaxial with at least a portion of a trajectory path for insertion of the stylet or obturator into the tissue. 
     
     
         8 ) The method of  claim 1  wherein at least one channel is created by extending a stylet or obturator at least some distance exterior to a cannula that is coaxial with the cannula at a point of contact with the tissue which is not coaxial with linear path for penetration of the tissue by the stylet or obturator. 
     
     
         9 ) The method of  claim 1  wherein at least one channel is created by extending a stylet with a curved shape from a relatively straight cannula to create a curved channel. 
     
     
         10 ) The method of  claim 1  wherein at least one channel is created coaxially to the cannula in combination with at least one curved channel that is arcuate or helical. 
     
     
         11 ) A method for introducing a substance to a region of a body through a cannula without introducing bubbles into the region of the body comprising:
 purging the cannula of bubbles with the substance,   placing a device comprising a stylet or obturator into the cannula,   again purging any bubbles with additional amounts of the substance,   inserting the cannula into the body while maintaining a seal between the stylet and the cannula and   then retracting or removing the stylet while providing a volumetric flow rate of the substance into the cannula and out of an outlet from the catheter.   
     
     
         12 ) The method of  claim 11  wherein providing the volumetric flow rate comprises delivering a volume of the substance approximately equal to the volume of a portion of the stylet or obturator that has been removed from the body. 
     
     
         13 ) A method for introducing a substance to a region of soft mass through a cannula without introducing bubbles, by first inserting a device such as a stylet or obturator in to the cannula, purging any bubbles with the substance, inserting the cannula into the soft mass while maintaining a seal around the stylet, and then retracting or removing the stylet or obturator while maintaining a volumetric flow rate of the substance in to the cannula. 
     
     
         14 ) The method of  claim 13  wherein a portion of the stylet or obdurator penetrates the body and providing the volumetric flow rate comprises delivering a volume of the substance approximately equal to the volume of the portion of the stylet or obturator. 
     
     
         15 ) The method of  claim 1  wherein the substance is selected from the group consisting of a liquid, a drug cells, and a viral vector. 
     
     
         16 ) The method of  claim 11  wherein the substance is selected from the group consisting of a liquid, a drug, cells, and a viral vector. 
     
     
         17 ) The method of  claim 1  wherein after insertion of the stylet or obturator, one of the following steps is performed: a) only the stylet or obturator is removed and the substance is delivered through the cannula, b) the stylet or obturator and the cannula are removed and replaced by another device for substance delivery, c) one or more curved channels are created by first extending the curved stylet, retracting it, retracting the cannula and stylet together, and then repeating these steps one or more times, d) a device is used to deliver a substance for some finite amount of time and is then subsequently removed or e) the device used to deliver the substance is permanently implanted. 
     
     
         18 ) The method of  claim 1  where the cannula and stylet or obturator are delivered through a secondary (outer) cannula or catheter, such that when the channel(s) have been created, the first cannula and stylet or obturator are removed and the substance is delivered through the secondary (outer) cannula or catheter. 
     
     
         19 ) The method of  claim 11  where the stylet and cannula are inserted into a secondary, outer cannula or catheter prior to inserting the stylet or cannula into the body. 
     
     
         20 ) The method of  claim 11  where the stylet and cannula are first inserted into a catheter and the catheter is then purged with the substance prior to inserting the stylet or cannula into the body. 
     
     
         21 ) The method of  claim 13  where a secondary, outer cannula or catheter is first purged with the substance and the stylet is then inserted into the secondary, outer cannula or catheter prior to inserting the stylet or into the body. 
     
     
         22 ) A device for creating a tissue channel consisting of a cannula and a curved stylet that can be straightened by leverage forces, the cannula is sufficiently rigid as to apply leverage force against the curved stylet to straighten the curved stylet when retracted into the cannula. 
     
     
         23 ) The device of  claim 22  wherein there is a seal between the cannula and the stylet to allow for purging of air. 
     
     
         24 ) The device of  claim 23  wherein the cannula and stylet are present within a flexible catheter. 
     
     
         25 . The device of  claim 24  wherein the cannula has a luer that can be removed and reattached to the catheter to facilitate tunneling. 
     
     
         26 . The device of  claim 25  wherein there is a seal between the cannula and the catheter and a side port in the catheter to purge the air from an interface between the catheter and cannula and back fill the catheter during cannula removal. 
     
     
         27 . The device of  claim 22  where the stylet comprises a microelectrode, a fiber optic element, a micro coil, an ultrasound transducer or a medical diagnostic device. 
     
     
         28 ) The method of  claim 1  where the stylet is used to perform an additional function other than creating the channel, and the additional function is selected from the class of performing diagnostics, taking measurements and delivering therapy prior to being retracted or removed.