Steering an implantable medical lead via a rotational coupling to a stylet

Abstract

An implantable medical lead has a torsional stiffness and is rotationally coupled to a stylet. Applying rotation directly to the lead in turn causes rotation of the stylet. Where the stylet has a bent tip for purposes of steering the lead, the rotation applied to the lead rotates the bent tip so that the lead can be steered by rotating the lead rather than rotating a hub of the stylet. The rotational coupling may be achieved through one or more features provided for the lead and/or the stylet, such as a feature within a lumen of the lead that mates to a feature along the stylet or a feature of the stylet hub that engages the proximal end of the lead. The torsional stillness of the lead may be provided by adding a feature within the lead body, such as a braided metal wire or an overlapping foil.

What is claimed is: 
     
         1 . A method of guiding an implantable medical lead, comprising:
 providing the implantable medical lead with an elongated insulative body providing a length of the lead and with a torsional stiffness over the length of the implantable medical lead, the torsional stiffness being sufficient to impart rotation over the length of the lead when rotation is applied at a point along the length that includes the torsional stiffness; and   upon insertion of a stylet with a distal guide bend into a lumen defined by the elongated insulative body of the implantable medical lead, providing a plurality of rotational couplings of the stylet to coupling features within the lumen that are defined by the elongated insulative body of the implantable medical lead such that imparting rotation directly to the implantable medical lead at the point along the length imparts rotation to the stylet to direct the distal guide bend.   
     
     
         2 . The method of  claim 1 , wherein the coupling feature within the lumen comprises at least one of a hexagonal passage, a star passage, and a square passage. 
     
     
         3 . The method of  claim 1 , wherein the coupling feature on the stylet comprises at least one of a hexagonal shaft, a star shaped shaft, and a square shaped shaft. 
     
     
         4 . The method of  claim 1 , wherein providing the rotational coupling comprises providing a coupling between a proximal end of the implantable medical lead and a hub of the stylet. 
     
     
         5 . The method of  claim 4 , wherein the coupling between the proximal end of the implantable medical lead and the hub comprises at least one of a tapered frictional fit, a threaded fit, and a splined fit. 
     
     
         6 . The method of  claim 1 , wherein providing the implantable medical lead with the torsional stiffness over the length of the implantable medical lead comprises including a metal shield within a jacket of the implantable medical lead. 
     
     
         7 . The method of  claim 6 , wherein the metal shield comprises a metal wire braid. 
     
     
         8 . The method of  claim 1 , wherein the point along the length is spaced longitudinally from the rotational coupling. 
     
     
         9 . An implantable medical lead kit, comprising:
 an implantable medical lead with an elongated insulative body providing a length of the lead and with a torsional stiffness over the length of the implantable medical lead, the torsional stiffness being sufficient to impart rotation over the length of the lead when rotation is applied at any point along the length that includes the torsional stiffness; and   a stylet within a lumen defined by the elongated insulative body of the implantable medical lead, the stylet having a distal guide bend and the stylet being rotationally coupled to a plurality of coupling features within the lumen and defined by the elongated insulative body of the implantable medical lead such that imparting rotation directly to the implantable medical lead at one or more points along the length imparts rotation to the stylet to direct the distal guide bend.   
     
     
         10 . The implantable medical lead kit of  claim 9 , wherein the coupling feature within the lumen comprises at least one of a hexagonal passage, a star passage, and a square passage. 
     
     
         11 . The implantable medical lead kit of  claim 9 , wherein the coupling feature on the stylet comprises at least one of a hexagonal shaft, a star shaped shaft, and a square shaped shaft. 
     
     
         12 . The implantable medical lead kit of  claim 9 , wherein a proximal end of the implantable medical lead is rotationally coupled to a hub of the stylet. 
     
     
         13 . The implantable medical lead kit of  claim 12 , wherein the coupling between the proximal end of the implantable medical lead and the hub comprises at least one of a tapered frictional fit, a threaded fit, and a splined fit. 
     
     
         14 . The implantable medical lead kit of  claim 9 , wherein the implantable medical lead comprises a metal shield within a jacket of the implantable medical lead that provides the torsional stiffness over the length of the implantable medical lead. 
     
     
         15 . The implantable medical lead kit of  claim 14 , wherein the metal shield comprises a metal wire braid. 
     
     
         16 . The implantable medical lead kit of  claim 9 , wherein the point along the length is spaced longitudinally from the rotational coupling.