System and method for electrically probing and providing medical electrical stimulation

Abstract

A system for providing medical electrical stimulation including a lead assembly and a cannula. The lead assembly includes a lead body and a needle tip. The lead body has a distal section and a proximal section. The needle tip is formed of an electrically conductive material and is connected to the distal section of the lead body. The lead body is slidably disposed within a cannula lumen, with a distal end of the cannula being selectively connected to an abutment surface of the needle tip such that the needle tip extends distal the cannula to define a needle probe. With this construction, the lead assembly can be delivered to a desired implantation site via manipulation of the cannula and/or energization of the needle tip, and the cannula can be removed from the lead body without requiring movement of the needle tip.

1 . A method of providing temporary electrical stimulation to bodily tissue of a patient at a stimulation site, the method comprising:
 providing a delivery system including:
 a lead assembly including:
 a lead body having a distal section and a proximal section, 
 a needle tip formed of an electrically conductive material and defining a proximal segment, an intermediate segment, and a distal segment tapering in outer diameter from the intermediate segment, wherein the intermediate segment forms an abutment surface and the lead body is connected to the proximal segment of the needle tip to establish an electrically conductive connection; 
 
 a cannula having a distal end, a proximal end, and a lumen; 
   disposing the lead body within the cannula lumen such that the distal end of the cannula abuts the abutment surface of the needle tip and the distal section of a needle tip extends distal the distal end of the cannula;   percutaneously delivering the needle tip toward the stimulation site by applying a manipulation force to the cannula;   positioning the needle tip at the stimulation site;   proximally withdrawing the cannula from the lead body with the proximal section of the lead body being external the patient; and   periodically applying a stimulation energy to the needle tip via a power source electrically coupled to the lead body external the patient to electrically stimulate the stimulation site.   
     
     
         2 . The method of  claim 1 , wherein the method is performed as part of a sacral nerve stimulation procedure, and further wherein percutaneously delivering the needle tip includes:
 locating a sacral foramen;   inserting the needle tip into the sacral foramen; and   wherein the needle tip and the cannula are sized for insertion into the sacral foramen.   
     
     
         3 . The method of claim  23 , further comprising:
 monitoring a response of a patient over a period of time during which stimulation is repeatedly, periodically applied to the needle tip; and   determining whether to implant a permanent sacral nerve stimulation electrode based upon the monitoring.   
     
     
         4 . The method of  claim 1 , wherein proximally withdrawing the cannula from the lead body includes:
 separating the cannula from the needle tip via an axial force applied to the needle tip in a distal direction relative to the cannula.   
     
     
         5 . The method of  claim 4 , wherein applying an axial force includes applying a pushing force onto the proximal section of lead body proximal the proximal end of the cannula. 
     
     
         6 . The method of  claim 1 , wherein the intermediate segment of the needle tip forms a radial face relative to the proximal segment, the method further comprising:
 implanting the needle tip and the lead body at the stimulation site, characterized by the radial face inhibiting axial dislodgement of the needle tip and the lead body.   
     
     
         7 . The method of  claim 1 , wherein the lead body forms an exposed electrode surface longitudinally spaced from the needle tip in a proximal direction, and further wherein periodically applying a stimulation energy includes operating the lead assembly as a bipolar electrode assembly.