Temporary stimulation lead with polymer electrodes and method of manufacture
View Patent ↗A temporary medical lead in which stimulating electrical energy is transmitted to body tissue through the lead electrodes via ionic conduction within the hydrogel material is described. The hydrophilic hydrogel material consists of a porous structure into which conductive salt ions are diffused. In addition the structure of the hydrogel material can be loaded with a single or combination of therapeutic drugs which is elutable from the electrode.
1. A method for making a medical lead, comprising the steps of:
a) providing a lead body comprising a lead body proximal region and a lead body distal region positioned along a longitudinal axis;
b) providing at least two insulated conductor wires extending through the lead body proximal region, along the longitudinal axis, to the lead body distal region;
c) cutting a notch through the insulation of each of the conductor wires, thereby exposing an area of bare conductor wire;
d) placing conductor bands and insulation bands together in an alternating linear fashion along the longitudinal axis and over the at least two conductor wires, wherein the conductor bands are composed of a hydrophilic thermoplastic polyurethane elastomer and disposed intermediate two of the insulator bands to thereby insulate the conductor bands from each other, and wherein the area of bare conductor wire at the notch of one of the conductor wires is in electrical contact with a respective conductor band; and
e) heat treating the temporary medical lead so as to create individual electrical connections between a conductor wire and a conductor band.
2. The method of claim 1 including individually coating the conductor wires with an insulative polymer selected from the group consisting of polyurethane, polyimide, silicone, polytetrafluoroethylene, ethylene tetrafluoroethylene, fluoropolymers and combinations thereof.
3. The method of claim 1 including cutting each conductor wire, thereby terminating electrical conductivity distal of the cut.
4. The method of claim 1 including heat treating the medical lead at a temperature of about 200° C. to about 300° C. for about 30 minutes to about 300 minutes.
5. The method of claim 1 including soaking the medical lead in saline for about 10 minutes to about 3 hours to allow for diffusion of salt ions into the conductor bands.
6. The method of claim 1 including loading the conductor bands of the medical lead with a therapeutic drug selected from the group consisting of beclamethason, baclofen, dexamethosone, coumadin, heparin, their derivatives, and combinations thereof.
7. The method of claim 1 including configuring the medical lead being connectable to a medical device selected from the group consisting of a pacemaker, defibrillator, and a neurostimulator.
8. A method for providing a medical lead configured for electrical stimulation of body tissue, comprising the steps of:
a) providing at least a first and a second conductor bands composed of an elastomer that is electricity conductible through ionic conduction, the first and second conductor bands each having a conductor band lumen extending along a conductor band length between and to respective conductor band proximal and distal ends;
b) providing at least three insulator bands, each insulator band having an insulator band lumen extending along an insulator band length;
c) disposing one of the conductor bands intermediate two of the insulator bands to thereby insulate the first and second conductor bands from each other; and
d) providing at least a first insulated conductor wire and a second insulated conductor wire, each conductor wire having respective first and second conductor wire lengths extending from a proximal conductor wire region, through the conductor band lumens and the insulator band lumens to a distal conductor wire region,
e) providing the first and second conductor wires with respective first and second notches in their insulation, thereby exposing first and second uninsulated conductor wire lengths with at least a portion of the first and second notches being radially aligned in a perpendicular orientation to a longitudinal axis of the respective first and second conductor band lengths, and
e) heat treating a heat shrink tubing covering the first and second conductor bands spaced from each other by the at least three insulator bands, thereby providing the first and second conductor bands in an intimate electrically conductive contact relationship with the first and second uninsulated conductor wire lengths at their notches somewhere between the respective first and second conductor band proximal and distal ends thereof.
9. The method of claim 8 including cutting at least the first and the second conductor wires at a location that is distal of the respective first and second notches so that electrical conductivity terminates at the cut.
10. The method of claim 9 including providing the cut being radially aligned with one of the respective first and second insulator bands.
11. The method of claim 8 including providing the at least three insulator bands being composed of a biocompatible electrically insulative material selected from the group consisting of polyurethane, polyimide, silicone, polytetrafluoroethylene, Ethylene tetrafluoroethylene, fluoropolymers and combinations thereof.
12. The method of claim 8 including providing the insulator band length ranging from about 1 cm to about 1.0 cm and providing an insulator band diameter ranging from about 1 mm to about 6 mm.
13. The method of claim 8 including providing the conductor band length ranging from about 1 cm to about 10 cm and providing a conductor band diameter ranging from about 1 mm to about 6 mm.
14. The method of claim 8 including infusing salt ions from a salt solution into the at least the first and the second conductor bands, thereby providing the first and second conductor hands being ionically conductive.
15. The method of claim 8 including providing the elastomer as a hydrophilic thermoplastic polyurethane elastomer loaded with a therapeutic drug selected from the group consisting of beclamethason, baclofen, dexamethosone, coumadin, heparin, their derivatives, and combinations thereof.
16. The method of claim 8 including providing the first and second conductor wires with insulation selected from the group consisting of polyurethane, polyimide, silicone, polytetrafluoroethylene, ethylene tetrafluoroethylene, fluoropolymers and combinations thereof.
17. The method of claim 8 including configuring the medical lead being connectable to a medical device selected from the group consisting of a pacemaker, defibrillator, and a neurostimulator.