Dynamic coil for implantable stimulation leads
View Patent ↗An implantable biomedical conductor assembly is configured for at least partial insertion in a living body. The implantable conductor assembly includes an inner tubular structure and an outer tubular structure generally surrounding the inner tubular structures such that a gap of less than about 0.030 inches exists there between. A dynamic coil is located in the gap. The dynamic coil includes a plurality of insulated conductors that are coiled generally at or below a yield point. The insulated conductors are permitted to expand within the gap to engage an inner surface of the outer tubular structure in an expanded coiled configuration. At least one mechanical restraint at each of a distal end and a proximal end retains the dynamic coil in the tubular structures. Free ends of the insulated conductors extend beyond the proximal and distal ends to facilitate attachment to electrodes and connectors.
1. An implantable biomedical conductor assembly configured for at least partial insertion in a living body, comprising:
an inner tubular structure;
an outer tubular structure generally surrounding the inner tubular structure so that a gap of less than or equal to 0.030 inches exists between the inner tubular structure and the outer tubular structure; and
a dynamic coil located in the gap, the dynamic coil comprising a plurality of insulated conductors coiled below a yield point of the insulated conductors, the dynamic coil being permitted to expand within the gap to engage an inner surface of the outer tubular structure in an expanded coiled configuration, at least one mechanical restraint being located at or near each of a distal end and a proximal end of the outer tubular structure to retain the dynamic coil between at least portions of the inner tubular structure and the outer tubular structure in the coiled configuration below the yield point of the insulated conductors;
wherein free ends of the insulated conductors extend beyond the proximal and distal ends of the outer tubular structure and are attached to corresponding connectors and electrodes, the free ends being relaxed from the coiled configuration into a substantially straight configuration.
2. The implantable conductor assembly of claim 1 , wherein at least a portion of the dynamic coil unravels if one or more of the mechanical restraints is removed, and any unraveled coils comprise a diameter greater than a diameter of the dynamic coil in the expanded coiled configuration.
3. The implantable conductor assembly of claim 1 , wherein at least one of the mechanical restraints comprises attachment locations that secure the insulated conductors to at least one of the inner tubular structure or the outer tubular structure at or near at least one of the proximal end or the distal end of the outer tubular structure.
4. The implantable conductor assembly of claim 1 , wherein at least one of the mechanical restraints comprises free ends of the insulated conductors attached to at least one of the electrodes or the connectors.
5. The implantable conductor assembly of claim 1 , wherein the coiled configuration comprises a plurality of insulated conductors having portions thereof arranged in a single plane.
6. The implantable conductor assembly of claim 1 , wherein the expanded coiled configuration comprises up to twelve insulated conductors, the implantable conductor assembly including a percent elongation in a range between about 10 percent to about 35 percent.
7. The implantable conductor assembly of claim 1 , wherein the expanded coiled configuration comprises up to sixteen insulated conductors, the implantable conductor assembly including a percent elongation in a range between about 10 percent to about 25 percent.
8. The implantable conductor assembly of claim 1 , wherein an outside diameter of the implantable conductor assembly is less than or equal to 0.080 inches.
9. The implantable conductor assembly of claim 1 , wherein the inner tubular structure comprises one of a stylet coil, a braided structure, extruded tube, or a combination thereof.
10. The implantable conductor assembly of claim 1 , wherein the inner tubular structure comprises a lumen sized to receive a stylet wire.
11. The implantable conductor assembly of claim 1 , wherein the coiled configuration comprises up to twelve coiled conductors and meets the bending radius and flex fatigue requirements set forth in European Standard EN 45502-2-1:2003, Section 23.3.
12. The implantable conductor assembly of claim 1 , wherein the implantable conductor assembly comprises a portion of a medical electrical lead or a fluid delivery device.
13. An implantable biomedical conductor assembly configured for at least partial insertion in a living body, comprising:
a tubular structure comprising a lumen; and
a dynamic coil located in the lumen, the dynamic coil including a plurality of insulated conductors coiled below a yield point of the insulated conductors, the dynamic coil being permitted to expand within the tubular structure to engage an inner surface of the lumen in an expanded coiled configuration, at least one mechanical restraint being located at each of a distal end and a proximal end of the tubular structure to retain the dynamic coil in the lumen in the coiled configuration below the yield point of the insulated conductors;
wherein free ends of the insulated conductors extend beyond proximal and distal ends of the tubular structure to facilitate attachment to connectors and electrodes, respectively, the free ends being relaxed from the coiled configuration into a substantially straight configuration.
14. The implantable conductor assembly of claim 13 , wherein at least a portion of the dynamic coil unravels if one or more of the at least one mechanical restraint is removed, and any unraveled coils include a diameter greater than a diameter of the dynamic coil in the expanded coiled configuration.
15. The implantable conductor assembly of claim 13 , wherein at least one of the at least one mechanical restraint includes attachment locations configured to secure the insulated conductors to the tubular structure at or near at least one of the proximal end or the distal end of the tubular structure.
16. The implantable conductor assembly of claim 13 , wherein at least one of the at least one mechanical restraint includes free ends of the insulated conductors attached to at least one of the electrodes or the connectors.
17. The implantable conductor assembly of claim 13 , comprising an inner tubular structure disposed within the tubular structure, the inner tubular structure including at least one of a stylet coil, a braided structure, or an extruded tube.
18. The implantable conductor assembly of claim 17 , wherein the tubular structure and the inner tubular structure are separated by a gap of less than or equal to 0.030 inches.
19. An implantable biomedical conductor assembly configured for at least partial insertion in a living body, comprising:
an inner tubular structure;
an outer tubular structure generally disposed around the inner tubular structure, wherein the inner tubular structure is separated from the outer tubular structure by a gap; and
a dynamic coil disposed within the gap, the dynamic coil including a plurality of insulated conductors coiled below a yield point of the conductors, the dynamic coil being permitted to expand within the gap to engage an inner surface of the outer tubular structure in an expanded coiled configuration, at least one mechanical restraint being located at or near each of a distal end and a proximal end of the outer tubular structure to retain the dynamic coil between at least portions of the inner tubular structure and the outer tubular structure in the coiled configuration below the yield point of the insulated conductors, wherein each of the insulated conductors includes two free ends, one free end extending beyond the proximal end of the outer tubular structure and the other free end extending beyond the distal end of the outer tubular structure, each of the free ends being relaxed from the coiled configuration into a substantially straight configuration and configured to be attached to an electrode or a connector.
20. The implantable conductor assembly of claim 19 , wherein at least one of the at least one mechanical restraint includes attachment locations configured to secure the insulated conductors to the outer tubular structure at or near at least one of the proximal end or the distal end of the outer tubular structure.
21. The implantable conductor assembly of claim 19 , wherein the inner tubular structure includes a lumen sized to receive a stylet wire, and wherein the gap between the inner tubular structure and the outer tubular structure is 0.030 inches or less.