Apparatus for accurately controlling needle extension

Abstract

Devices are illustrated which provide for accurately controlling the extension of a needle from a protective sheath to increase accuracy and improve the outcome of the treatment procedure.

What is claimed is: 
     
         1 . A medical device comprising:
 a needle comprising a proximal portion and a distal portion, wherein the distal portion of the needle comprises a sharpened tip;   a sheath comprising a proximal portion, a distal portion, and a lumen extending between the proximal portion and the distal portion of the sheath, the lumen being defined by an inner surface of the sheath, wherein at least a portion of the needle is movably disposed through the lumen of the sheath;   a plurality of spaced apart first engagement members affixed to one of the proximal portion of the needle or the inner surface of the sheath;   a second engagement member affixed to the other of the proximal portion of the needle or the inner surface of the sheath, wherein the second engagement member is configured to releasably engage each of the first engagement members to provide incremental movement of the sheath relative to the needle.   
     
     
         2 . The medical device of  claim 1 , further comprising a handle in communication with the sheath, where the handle is configured for axial retraction or extension of the sheath to expose or conceal the distal portion of the needle. 
     
     
         3 . The medical device of  claim 1 , wherein the second engagement member comprises an annular component comprising at least one ridge disposed about a surface of the annular component;
 wherein the plurality of first engagement members is affixed to the inner surface of the sheath comprising at least one slot disposed into the inner surface of the sheath;   wherein the ridge of the annular component is configured to frictionally engage the slot of the sheath.   
     
     
         4 . The medical device of  claim 3 , wherein the at least one slot of the sheath further comprises a first slot disposed into the inner surface of the sheath, a second slot disposed into the inner surface of the sheath and apart from the first slot, and a third slot disposed into the inner surface of the sheath and apart from the second slot and first slot. 
     
     
         5 . The medical device of  claim 1 , wherein the second engagement member comprises an annular component comprising at least one slot disposed into the surface of the annular component;
 wherein the plurality of first engagement members is affixed to the inner surface of the sheath, wherein each sheath further comprises at least one ridge disposed about the inner surface of the sheath;   wherein the slot of the annular component is configured to frictionally engage the ridge of the sheath.   
     
     
         6 . The medical device of  claim 5 , wherein the at least one slot of the annular component further comprises a first slot disposed into the surface of the annular component, a second slot disposed into the surface of the annular component and apart from the first slot, and a third slot disposed into the surface of the annular component and apart from the second slot and first slot. 
     
     
         7 . The medical device of  claim 1 , wherein the second engagement member comprises an annular component comprising at least one wing disposed about an outer surface of the annular component;
 wherein the plurality of first engagement members is affixed to the inner surface of the sheath further comprising at least one change in a diameter,   wherein the wing of the annular component is configured to frictionally engage the change in the diameter of the sheath.   
     
     
         8 . The medical device of  claim 7 , wherein the at least one change in the diameter of the sheath further comprises:
 a first change in diameter;   a second change in diameter; and   a third change in diameter;   wherein the first change in diameter comprises a diameter smaller than a diameter of the second and third changes in diameter, wherein the second change in diameter comprises a diameter larger than the first change in diameter, and wherein the third change in diameter comprises a diameter larger than the second change in diameter.   
     
     
         9 . The medical device of  claim 8 , wherein the first change in diameter, second change in diameter, and third change in diameter each traverse a length of the sheath along a longitudinal axis of the sheath. 
     
     
         10 . The medical device of  claim 9 , wherein each of the first, second, and third changes in diameter traverse a different length of the sheath along the longitudinal axis. 
     
     
         11 . The medical device of  claim 7 , wherein the annular component further comprises a retrieval loop comprising a proximal portion and a distal portion, wherein the distal portion is attached to the at least one wing of the annular component, and wherein the retrieval loop is configured to compress the at least one wing of the annular component when the proximal portion of the retrieval loop is pulled. 
     
     
         12 . The medical device of  claim 7 , wherein the sheath further comprises a retrieval slot disposed about an inner surface of the sheath, wherein the retrieval slot is configured to slideably engage the at least one wing of the annular component. 
     
     
         13 . The medical device of  claim 1 , wherein the proximal portion of the needle is sufficiently flexible such that angulation of an endoscope is not unduly diminished or hindered when disposed through a working channel of the endoscope. 
     
     
         14 . The medical device of  claim 1 , wherein the plurality of spaced apart first engagement members are affixed to the proximal portion of one of the needle or the inner surface of the sheath;
 and the second engagement member is affixed to the proximal portion of the other of the needle or the inner surface of the sheath.   
     
     
         15 . A medical device comprising:
 a needle comprising a proximal portion and a distal portion, wherein the distal portion of the needle comprises a sharpened tip;   a sheath comprising a proximal portion, a distal portion, and a lumen extending between the proximal portion and the distal portion of the sheath, the lumen being defined by an inner surface of the sheath, wherein at least a portion of the needle is movably disposed through the lumen of the sheath;   an annular component disposed around a portion of a surface of the needle, wherein the annular component is configured to incrementally engage the inner surface of the sheath; and   a handle attached to the sheath and the needle, where the handle is configured for axial retraction and extension of the sheath to incrementally engage the annular component and expose or conceal a distal portion of the needle.   
     
     
         16 . The medical device of  claim 15 , wherein the needle further comprises at least one marker, wherein the marker is configured for visualization by a direct or indirect visualization device. 
     
     
         17 . The medical device of  claim 15 , further comprising a connector connected to a proximal portion of the handle, wherein the connector is configured to receive a syringe. 
     
     
         18 . The medical device of  claim 15 , wherein the proximal portion of the needle is sufficiently flexible such that angulation of an endoscope is not unduly diminished or hindered when disposed through a working channel of the endoscope. 
     
     
         19 . A medical device comprising:
 a needle comprising a proximal portion and a distal portion, wherein the distal portion of the needle comprises a sharpened tip;   a sheath comprising a proximal portion, a distal portion, and a lumen extending between the proximal portion and the distal portion of the sheath, the lumen being defined by an inner surface of the sheath, wherein at least a portion of the needle is movably disposed through the lumen of the sheath;   a first accurate needle extension member in communication with the inner surface of the sheath; and   a second accurate needle extension member in communication with the needle, wherein the first accurate needle extension member is configured for engagement with the second accurate needle extension member for accurately extending a length of the needle from the distal portion of the sheath.   
     
     
         20 . The medical device of  claim 19 , wherein the first accurate needle extension device comprises an annular component disposed about the needle, and the second accurate needle extension member is disposed in the inner surface of the sheath.