Indwelling Nerve Block Catheters

Abstract

A nerve block catheter system employs an indwelling, flexible catheter comprising a tissue lock to retain the catheter tip in pharmacologically proximity to a target nerve and optionally, a decoupler that insulates the tip of the catheter from proximal tissue movement.

What is claimed is: 
     
         1 . A nerve block catheter system comprising a flexible indwelling nerve block catheter and a rigid stylet, the catheter and stylet each comprising a proximal portion and a distal portion terminating in a distal tip, wherein:
 (a) the distal portion of the catheter comprises a tissue lock which engages target site tissue and thereby anchors the catheter to the tissue without axially advancing or retracting the catheter tip whereby the catheter tip is retained in pharmacological proximity to a target nerve, and the proximal portion of the catheter comprises an actuator of the tissue lock,   (b) the stylet is insertable axially in the catheter, providing rigidity to the catheter system during placement,   (c) the distal tip of the catheter and/or the stylet is sufficiently sharp to push through to the target site tissue, and   (d) the distal portion of the catheter and/or stylet comprises an electrode that senses and/or stimulates nerve electrical activity for placement.   
     
     
         2 . The nerve block catheter system of  claim 1  wherein the tissue lock is reversible and reversibly engages the target site tissue without axially advancing or retracting the catheter tip. 
     
     
         3 . The nerve block catheter system of  claim 1  wherein the system further comprises a skin-mounted decoupler that insulates the tip of the catheter from proximal tissue movement. 
     
     
         4 . The nerve block catheter system of  claim 1  wherein the decoupler comprises a hub comprising a cylindrical chamber that absorbs axial movement of the catheter 
     
     
         5 . The nerve block catheter system of  claim 1  wherein the catheter comprises a compliant polymeric material. 
     
     
         6 . The nerve block catheter system of  claim 1  wherein the lock comprises one or more protrusions and the actuator alternatively causes the protrusions to engage or disengage the target site tissue. 
     
     
         7 . The nerve block catheter system of  claim 1  wherein the protrusions are bulges, bladders, barbs, or threads. 
     
     
         8 . The nerve block catheter system of  claim 1  wherein the catheter comprises first and second axial lumens, the first lumen comprising a distal aperture that contains and conducts anesthetic in pharmaceutical proximity to the target nerve, and the second lumen comprising an aperture that conducts a flowable adhesive or vacuum that provide the lock. 
     
     
         9 . The nerve block catheter system of  claim 1  wherein the first and second lumens are inner and outer coaxial lumens, and the aperture of the second lumen is one of a plurality of radially-oriented apertures. 
     
     
         10 . The nerve block catheter system of  claim 1  wherein the lock comprises one or more apertures and the actuator comprises a valve wherein opening and closing the valve creates and releases a tissue-adhering vacuum at the apertures. 
     
     
         11 . The nerve block catheter system of  claim 1  wherein the lock comprises one or more apertures and the actuator comprises a valve wherein opening and closing the valve creates and releases a tissue-adhering vacuum at the apertures. 
     
     
         12 . The nerve block catheter system of  claim 1  wherein the lock further comprises a chamfer or ridge at the distal tip of the catheter that prevents axial motion of the catheter by causing target site tissue to embed in the tip of the catheter. 
     
     
         13 . The nerve block catheter system of  claim 1  wherein the actuator comprises a rotatable knob wherein rotation of the knob alternatively causes the lock to engage or disengage the target tissue. 
     
     
         14 . The nerve block catheter system of  claim 1  wherein the actuator is a lever or button, wherein pushing or pulling on the lever or button alternatively causes the lock to engage or disengage the target tissue. 
     
     
         15 . The nerve block catheter system of  claim 1  wherein the electrode is one of a plurality of electrodes, and the distal portion of the catheter and the distal portion of the stylet comprise the electrodes. 
     
     
         16 . The nerve block catheter system of  claim 1  wherein the electrode senses nerve native and/or evoked electrical activity. 
     
     
         17 . The nerve block catheter system of  claim 1  wherein the electrode stimulates nerve activity which is detected as patient movement or sensation. 
     
     
         18 . The nerve block catheter system of  claim 1  wherein the electrode is one of a plurality of independent electrodes that resolve electric fields of the nerve for placement. 
     
     
         19 . The nerve block catheter system of  claim 1  wherein the catheter proximal portion comprises a hydrogel to decouple the catheter tip from movement of surrounding muscle and/or skin. 
     
     
         20 . A method of using the nerve block catheter system of  claim 1 , comprising steps:
 tracking the nerve with the electrode;   placing the catheter;   engaging the lock;   delivering a medicament;   detecting a resultant therapeutic effect;   disengaging the lock; and   removing the catheter.