Devices and methods for selectively deploying catheter instruments

Abstract

Catheters with deployable instruments (e.g., needles) can damage tissue if the instrument unintentionally deploys during use. Described herein are devices and methods for controlling the position of a deployable catheter instrument. In one embodiment, a catheter can include an instrument slidably disposed within an inner lumen of the catheter and coupled to at least one protrusion, as well as a retraction stop coupled to the catheter. The catheter can further include a biasing element coupled to the instrument that can urge the instrument proximally such that the at least one protrusion abuts against the retraction stop, as well as an advancing mechanism to selectively engage the instrument and urge it distally. In some embodiments, the biasing element can be omitted and a deployment stop can be included distal to the retraction stop. These configurations can prevent unintentional instrument deployment and provide greater positioning precision during instrument deployment.

What is claimed is: 
     
         1 . A catheter, comprising:
 an instrument slidably disposed within an inner lumen of the catheter, the instrument being coupled to at least one protrusion;   a retraction stop coupled to the catheter proximal to the at least one protrusion;   a biasing element coupled to the instrument and configured to urge the instrument proximally such that the at least one protrusion abuts against the retraction stop; and   an advancing mechanism configured to selectively engage the instrument and urge the instrument distally relative to the catheter.   
     
     
         2 . The catheter of  claim 1 , wherein the catheter is steerable using one or more control cables extending through the catheter. 
     
     
         3 . The catheter of  claim 2 , wherein the one or more control cables terminate at a position proximal to the retraction stop. 
     
     
         4 . The catheter of  claim 1 , wherein the advancing mechanism includes a tab coupled to a proximal portion of the instrument. 
     
     
         5 . The catheter of  claim 1 , wherein the advancing mechanism includes a clutch to selectively engage the instrument. 
     
     
         6 . The catheter of  claim 1 , further comprising at least one indicator light configured to activate when the advancing mechanism engages the instrument. 
     
     
         7 . The catheter of  claim 4 , wherein the clutch is positioned in a proximal portion of the catheter within a handle assembly. 
     
     
         8 . The catheter of  claim 1 , wherein the advancing mechanism includes one or more predetermined distance increments that can be selected to urge the instrument distally by the predetermined distance. 
     
     
         9 . The catheter of  claim 1 , wherein the biasing element is positioned in a proximal portion of the catheter within a handle assembly. 
     
     
         10 . The catheter of  claim 1 , wherein the retraction stop is positioned such that a distal tip of the instrument is proximal to a distal tip of the catheter when the at least one protrusion is abutting against the retraction stop. 
     
     
         11 . The catheter of  claim 10 , wherein the advancing mechanism is configured to advance the instrument distally such that the distal tip of the instrument is distal to the distal tip of the catheter. 
     
     
         12 . The catheter of  claim 1 , wherein the at least one protrusion includes one or more fluid channels formed therein to allow fluid flow there-through. 
     
     
         13 - 21 . (canceled) 
     
     
         22 . A method for selectively deploying an instrument from a catheter, comprising:
 urging an instrument slidably disposed within an inner lumen of a catheter toward a proximal end of the catheter such that at least one protrusion coupled to the instrument abuts against a retraction stop coupled to a distal portion of the catheter;   coupling an advancing mechanism to the instrument to control movement of the instrument within the catheter; and   actuating the advancing mechanism to urge the instrument distally relative to the catheter.   
     
     
         23 . The method of  claim 22 , wherein urging the instrument distally relative to the catheter includes advancing the instrument from a first position wherein a distal tip of the instrument is proximal to a distal tip of the catheter to a second position wherein the distal tip of the instrument is distal to the distal tip of the catheter. 
     
     
         24 . The method of  claim 22 , further comprising steering the catheter into position within a patient's body. 
     
     
         25 . The method of  claim 22 , wherein the instrument is a needle and the method further comprises delivering fluid into tissue through an inner lumen of the needle and at least one outlet port formed in a distal portion of the needle. 
     
     
         26 . The method of  claim 25 , further comprising heating the fluid delivered into tissue using a heating element positioned within the inner lumen of the needle proximal to the at least one outlet port. 
     
     
         27 . The method of  claim 26 , further comprising delivering ablative energy into tissue from an ablation element disposed on the distal portion of the needle. 
     
     
         28 . The method of  claim 22 , further comprising activating at least one indicator light upon coupling the advancing mechanism to the instrument. 
     
     
         29 . A catheter, comprising:
 an instrument slidably disposed within an inner lumen of the catheter, the instrument being coupled to at least one protrusion;   a retraction stop coupled to the catheter;   a deployment stop coupled to the catheter and disposed distal to the retraction stop; and   an advancing mechanism configured to move the instrument relative to the catheter between a first position, wherein the at least one protrusion contacts the retraction stop, and a second position, wherein the at least one protrusion contacts the deployment stop.   
     
     
         30 . The catheter of  claim 29 , wherein the deployment stop is a distal end of a groove formed in a sidewall of the catheter that is configured to receive the at least one protrusion. 
     
     
         31 . The catheter of  claim 30 ,
 further comprising a second deployment stop at a distal end of a second groove formed in the sidewall of the catheter;   wherein rotation of the instrument about a longitudinal axis thereof can select which groove receives the at least one protrusion.   
     
     
         32 . The catheter of  claim 30 ,
 wherein the groove is tortuous and includes a plurality of longitudinally-extending portions connected by at least one transition; and   wherein any of proximal and distal translation of the instrument can move the at least one protrusion through one of the plurality of longitudinally-extending portions and rotation of the instrument can move the at least protrusion through the at least one transition.   
     
     
         33 . The catheter of  claim 29 ,
 wherein the deployment stop is a bulkhead having a through-hole formed therein to receive the at least one protrusion; and   wherein the at least one protrusion and the through-hole have complementary shapes to permit passage of the at least one protrusion through the through-hole in a first orientation and prevent passage of the at least one protrusion through the through-hole in a second orientation.   
     
     
         34 . The catheter of  claim 29 , wherein a position of the deployment stop relative to the retraction stop can be adjusted. 
     
     
         35 . The catheter of  claim 34 , wherein the deployment stop is coupled to an intermediate shaft disposed within the inner lumen of the catheter about the instrument. 
     
     
         36 . The catheter of  claim 29 , wherein the deployment stop is a detent formed in a sidewall of the catheter and the at least one protrusion is biased to extend into the detent when aligned therewith. 
     
     
         37 . The catheter of  claim 29 , further comprising a biasing element coupled to the instrument.