Minimally invasive methods for implanting a sacral stimulation lead

Abstract

Methods and apparatus for implanting a neural stimulation lead in a patient's body are described. A lead assembly comprises a pointed-tip stylet, a stimulation lead, and an optional tube to deploy a fixation element attached to the lead. One embodiment of the implant methods starts with inserting the pointed-tip lead assembly directly into tissue. After the desired implant position is determined, the pointed-tip component is separated from the stimulation lead and removed from the tissue, leaving the stimulation lead implanted. After confirmation that the stimulation lead is in the right tissue location, the pointed-tip component is removed from the body, leaving the stimulation lead in place. The stimulation lead can be connected to a neurostimulator to delivery therapies to treat neural disorders, such as urinary control disorders, fecal control disorders, sexual dysfunction, and pelvic pain, etc.

What is claimed is: 
     
         1 . A stimulation lead assembly, which comprises:
 a) a neural stimulation lead, comprising:
 i) an elongated, insulated lead body extending along a length from a proximal lead body portion to a distal lead body portion having a distal lead body end; 
 ii) at least one stimulation electrode at the distal lead body portion or at the distal lead body end; 
 iii) at least one electrical connector at the proximal lead body portion, wherein the electrical connector is configured for electrically connecting the lead to a pulse generator; 
 iv) at least one conductor providing electrical continuity from the connector to the electrode; 
   and
 v) at least one tapered coil having a smaller diameter coil end attached to the lead body and a larger diameter coil end spaced from the lead. body, 
 vi) wherein the tapered coil is twistable from a first configuration having the larger diameter coil end at a greater distance from the lead body than in a second configuration with the larger diameter coil end closer to the lead body than when in the first configuration; and 
   b) a tube that is sized to slide over the lead body to contact the at least, one tapered coil, twisted into the second configuration, and   c) wherein when the tube is slid in a proximal direction over the lead body and toward the connector, the at least one coil is configured to uncoil from the second configuration into the first configuration.   
     
     
         2 . The lead assembly of  claim 1  wherein the tapered coil extends longitudinally along the length of the lead body from the smaller diameter coil end to the larger diameter coil end. 
     
     
         3 . The lead assembly of  claim 1  wherein there are at least two tapered coils attached at different longitudinal location along the length of the lead body. 
     
     
         4 . The lead assembly of  claim 1  wherein the larger diameter coil end faces the proximal lead body portion. 
     
     
         5 . The lead assembly of  claim 1  wherein the larger diameter coil end faces the distal lead body portion. 
     
     
         6 . The lead assembly of  claim 1  wherein there are three tapered coils at spaced locations along the length of the lead body. 
     
     
         7 . The lead assembly of  claim 6  wherein at least one of the three tapered coils has its larger diameter end facing the proximal lead body end and at least another one of three tapered coils has its larger diameter end facing the distal lead body end. 
     
     
         8 . The lead assembly of  claim 1  wherein the tapered coil is made of a biocompatible metal selected from the group consisting of stainless steel, platinum, titanium, NP35N, Nitinol, and mixtures thereof. 
     
     
         9 . The lead assembly of  claim 1  wherein the lead body is of a polymeric material selected from the group consisting of silicone, polyurethane, and mixtures thereof. 
     
     
         10 . The lead assembly of  claim 1  wherein a hollow lumen extends along the entire length of the lead body from the proximal lead body portion to the distal lead body end. 
     
     
         11 . The lead assembly of  claim 10  including a pointed-tip stylet sized to be housed inside the lumen extending along the lead body. 
     
     
         12 . The lead assembly of  claim 11  wherein the stylet is longer than the lead body so that with a proximal end of the stylet detachably secured to the proximal lead body portion, a distal end of the stylet extends out past the distal lead body end. 
     
     
         13 . A neural stimulation lead, which comprises:
 a) an elongated, insulated lead body extending along a length from a proximal lead body portion to a distal lead body portion having a distal lead body end;   b) at least one stimulation electrode at the distal lead body portion or at the distal lead body end;   at least one electrical connector at the proximal lead body portion, wherein the electrical connector is configured for electrically connecting the lead to a pulse generator;   d) at least one conductor providing electrical continuity from the connector to the electrode; and   e) at least one tapered coil having a smaller diameter coil end attached to the lead body and a larger diameter coil end spaced from the lead body,   f) wherein the tapered coil is twistable from a first configuration having the larger diameter coil end at a greater distance from the lead body than in a second configuration with the larger diameter coil end closer to the lead body than when in the first configuration;.   
     
     
         14 . The lead of  claim 13  wherein the tapered coil extends longitudinally along the length of the lead body from the smaller diameter coil end to the larger diameter coil end. 
     
     
         15 . The lead of  claim 13  wherein there are at least two tapered coils attached at different longitudinal location along the length of the lead body. 
     
     
         16 . The lead of  claim 13  wherein the larger diameter coil end faces the proximal lead body portion. 
     
     
         17 . The lead of  claim 13  wherein the larger diameter coil end faces the distal lead body portion. 
     
     
         18 . The lead of  claim 13  wherein there are three tapered coils at spaced locations along the length of the lead body. 
     
     
         19 . The lead of  claim 18  wherein at least one of the three tapered coils has its larger diameter end facing the proximal lead body end and at least another one of three tapered coils has its larger diameter end facing the distal lead body end. 
     
     
         20 . The lead of  claim 13  wherein the tapered coil is made of a biocompatible metal selected from the group consisting of stainless steel, platinum, titanium, NP35N, Nitinol, and mixtures thereof. 
     
     
         21 . The lead of  claim 13  wherein the lead body is of a polymeric material selected from the group consisting of silicone, polyurethane, and mixtures thereof. 
     
     
         22 . The lead of  claim 13  wherein a hollow lumen extends along the entire length of the lead body from the proximal lead body portion to the distal lead body end.