Mri compatible handle and steerable sheath

Abstract

An MR compatible deflectable catheter and method of using the same is provided. The MR compatible deflectable catheter includes a steerable sheath having a tubular shaft. The tubular shaft receives first and second longitudinal movement wires at a distal end thereof. A control handle is coupled to a proximal end of the first and second longitudinal movement wires and causes longitudinal movement of the wires.

We claim: 
     
         1 . An MR compatible deflectable catheter comprising:
 a steerable sheath having a tubular shaft, said tubular shaft receiving first and second longitudinal movement wires operably coupled to a distal end thereof; and   a control handle operably coupled to a proximal end of said first and second longitudinal movement wires, said control handle for operating longitudinal movement of said wires.   
     
     
         2 . The MR compatible deflectable catheter of  claim 1  wherein said longitudinal movement of said first and second longitudinal movement wires causes the distal end of said steerable sheath to deflect about 180 degrees from a longitudinal axis of the tubular shaft. 
     
     
         3 . The MR compatible deflectable catheter of  claim 1  wherein said tubular shaft further includes a pull ring at a distal end thereof and said first and second longitudinal movement wire are operably coupled thereto. 
     
     
         4 . The MR compatible deflectable catheter of  claim 1  wherein said tubular shaft further includes two internal lumens positioned on opposite sides of said tubular shaft for housing said first and second longitudinal movement wires. 
     
     
         5 . The MR compatible deflectable catheter of  claim 2  wherein said tubular shaft includes a reinforcement construct at the distal end thereof configured to allow said steerable sheath to deflect about 180 degrees from the longitudinal axis of the tubular shaft. 
     
     
         6 . The MR compatible deflectable catheter of  claim 5  wherein said reinforcement construct is selected from a braided configuration, a coiled configuration, a slit tube configuration and combinations of the foregoing. 
     
     
         7 . The MR compatible deflectable catheter of  claim 1  wherein said shaft includes one or more pressure relief holes. 
     
     
         8 . The MR compatible deflectable catheter of  claim 1  wherein said shaft includes a transition section having a durometer that is higher than the durometer of the distal end of the shaft and less than the durometers of the proximal end of said shaft. 
     
     
         9 . The MR compatible deflectable catheter of  claim 1  wherein a lumen of said tubular shaft is lined or coated with a hydrophilic material. 
     
     
         10 . The MR compatible deflectable catheter of  claim 1  wherein said tubular shaft further includes a ferrous marker, a magnetic marker or a fluoroscopy marker disposed on said tubular shaft. 
     
     
         11 . The MR compatible deflectable catheter of  claim 1  wherein said tubular shaft further includes an active tracking coil along a length, said active tracking coil comprising chokes, transformers, impedances and combinations of the foregoing. 
     
     
         12 . The MR compatible deflectable catheter of  claim 11  wherein said active tracking coil comprises traces on a circuit board, a coiled wire, a dipole and combinations of the foregoing. 
     
     
         13 . The MR compatible deflectable catheter of  claim 1  wherein said tubular shaft further includes one or more fluid ports configured to allow for homeostasis of the steerable sheath. 
     
     
         14 . The MR compatible deflectable catheter of  claim 5  wherein said reinforcement construct comprises a non-metallic material selected from Kevlar, PEEK, Nylon, fabric, polyimide, fiber optic, silica glass and combinations of the foregoing. 
     
     
         15 . The MR compatible deflectable catheter of  claim 5  wherein said reinforcement construct comprises a combination of metallic and non-metallic materials. 
     
     
         16 . The MR compatible deflectable catheter of  claim 1  wherein said control handle further comprises
 a main body configured to receive first and second rack screws, said first and second rack screws including an inner threaded channel and an outer surface, the outer surface of said second rack screw including a thread at a distal end thereof and the outer surface of said first rack screw including a thread at a proximal end thereof, wherein said first longitudinal movement wire is operably coupled to the outer surface of said first rack screw and wherein said second longitudinal movement is operably coupled to the outer surface of said second rack screw; 
 first and second pinion gears coupled to the tubular shaft of said steerable sheath and operably engageable with the inner threaded channel of said first and second rack screws; and 
 a rotatable adjustment knob having an internal thread movable between a first position in which the internal thread in configured to engage the thread on the outer surface of said second rack screw and a second position in which the internal thread is configured to engage the thread on the outer surface of said first rack screw, wherein such engagement effects longitudinal movement of said longitudinal movement wires. 
 
     
     
         17 . An MR compatible deflectable catheter comprising:
 a steerable sheath having a tubular shaft, said tubular shaft receiving first and second longitudinal movement wires operably coupled to a distal end thereof;   a control handle operably coupled to a proximal end of said first and second longitudinal movement wires, said control handle a main body configured to receive first and second rack screws, said first and second rack screws including an inner threaded channel and an outer surface, the outer surface of said second rack screw including a thread at a distal end thereof and the outer surface of said first rack screw including a thread at a proximal end thereof, wherein said first longitudinal movement wire is operably coupled to the outer surface of said first rack screw and wherein said second longitudinal movement is operably coupled to the outer surface of said second rack screw;   first and second pinion gears coupled to the tubular shaft of said steerable sheath and operably engageable with the inner threaded channel of said first and second rack screws; and   a rotatable adjustment knob having an internal thread movable between a first position in which the internal thread in configured to engage the thread on the outer surface of said second rack screw and a second position in which the internal thread is configured to engage the thread on the outer surface of said first rack screw, wherein such engagement effects longitudinal movement of said longitudinal movement wires.   
     
     
         18 . A method of deflecting a deflectable catheter comprising:
 providing a steerable sheath having a tubular shaft, said tubular shaft receiving first and second longitudinal movement wires operably coupled to a distal end thereof;   providing a control handle having a main body configured to receive first and second rack screws, said first and second rack screws including an inner threaded channel and an outer surface, the outer surface of said second rack screw including a thread at a distal end thereof and the outer surface of said first rack screw including a thread at a proximal end thereof, wherein said first longitudinal movement wire is operably coupled to the outer surface of said first rack screw and wherein said second longitudinal movement is operably coupled to the outer surface of said second rack screw; first and second pinion gears coupled to the tubular shaft of said steerable sheath and operably engageable with the inner threaded channel of said first and second rack screws; and a rotatable adjustment knob having an internal thread movable between a first position in which the internal thread in configured to engage the thread on the outer surface of said second rack screw and a second position in which the internal thread is configured to engage the thread on the outer surface of said first rack screw;   rotating said rotatable adjustment knob in a clockwise direction;   engaging the outer thread of said second rack screw;   causing said pinion gears to movably advance along the threaded internal channel in a distal direction thereby causing said second longitudinal movement wire to move toward a distal direction and whereby tension on said first longitudinal movement wire is released causing the distal end of the steerable sheath to deflect to a maximum of 180 degrees from a longitudinal axis of said tubular shaft;   rotating said rotatable adjustment knob in a counterclockwise direction;   engaging the outer thread of said first rack screw;   causing said pinion gears to movably advance along the threaded internal channel in a proximal direction thereby causing said first longitudinal movement wire to move toward a distal direction and whereby tension on said second longitudinal movement wire is released causing the distal end of the steerable sheath to deflect in an opposite direction to a maximum of 180 degrees from a longitudinal axis of said tubular shaft.   
     
     
         19 . The MR compatible steerable sheath of  claim 9  wherein said hydrophilic material is selected from polytetrafluoroethylene, fluorinated ethylene propylene copolymer, nylons and combinations of the foregoing. 
     
     
         20 . The MR compatible steerable sheath of  claim 1  wherein the steerable sheath comprises a reinforced polymer tube in which the reinforcing material is non-metallic or a hybrid of metallic and non-metallic materials. 
     
     
         21 . The MR compatible steerable sheath of  claim 20  wherein the reinforcing material is selected from Kevlar, PEEK, Nylon, fabric, polyimide or combinations of the foregoing.