Self-curling cochlear electrode lead and method of manufacturing the same
An exemplary self-curling cochlear electrode lead includes a flexible body formed of a flexible insulating material, a shape memory polymer element that is embedded within the flexible body and that is configured to cause the self-curling cochlear electrode lead to transition to a curved spiral shape so as to conform with a curvature of a human cochlea when a temperature of the shape memory polymer element reaches a transition temperature, a plurality of electrode contacts arranged along a side of the flexible body, and a plurality of wires embedded within the flexible body and configured to electrically connect the plurality of electrode contacts to at least one signal source. Corresponding methods of manufacturing a self-curling cochlear electrode lead are also described.
1. A self-curling cochlear electrode lead adapted for insertion into a human cochlea, comprising:
a flexible body formed of a flexible insulating material;
a shape memory polymer element that is embedded within and completely surrounded by the flexible body and that is configured to cause the cochlear electrode lead to transition to a curved spiral shape so as to conform with a curvature of the human cochlea when a temperature of the shape memory polymer element reaches a transition temperature, the shape memory polymer element including a plurality of through-holes spaced apart along a longitudinal direction of the shape memory polymer element;
a plurality of electrode contacts arranged along a side of the flexible body, a position of each electrode contact included in the plurality of electrode contacts corresponding to a respective through-hole included in the plurality of through-holes; and
a plurality of wires embedded within the flexible body and configured to electrically connect the plurality of electrode contacts to at least one signal source.
2. The self-curling cochlear electrode lead of claim 1 , wherein the shape memory polymer element is in the shape of a channel and each through-hole included in the plurality of through-holes is arranged in a line in the longitudinal direction of the shape memory polymer element.
3. The self-curling cochlear electrode lead of claim 2 , wherein the channel is configured to guide the plurality of wires along the longitudinal direction of the shape memory polymer element.
4. The self-curling cochlear electrode lead of claim 1 , wherein the flexible body does not include a lumen configured to receive a stylet.
5. The self-curling cochlear electrode lead of claim 1 , wherein the shape memory polymer element has a U-shape when viewed in cross-section.
6. A self-curling cochlear electrode lead adapted for insertion into a human cochlea, comprising:
a flexible body formed of a flexible insulating material;
a plurality of shape memory polymer elements embedded within the flexible body and configured to cause the cochlear electrode lead to transition to a curved spiral shape so as to conform with a curvature of the human cochlea when a temperature of the plurality of shape memory polymer elements reaches a transition temperature, the plurality of shape memory polymer elements including a first shape memory polymer element and a second shape memory polymer element that are spaced apart from each other along a longitudinal direction of the cochlear electrode lead, the first shape memory polymer element and the second shape memory polymer element having a same transition temperature but having different curling rates;
a plurality of electrode contacts arranged along a side of the flexible body; and
a plurality of wires embedded within the flexible body and configured to electrically connect the plurality of electrode contacts to at least one signal source.
7. The self-curling cochlear electrode lead of claim 6 , wherein:
a length of the first shape memory polymer element spans two or more adjacent electrode contacts included in the plurality of electrode contacts; and
a length of the second shape memory polymer element spans two or more additional adjacent electrode contacts included in the plurality of electrode contacts.
8. The self-curling cochlear electrode lead of claim 6 , wherein:
a length of the first shape memory polymer element completely spans a first electrode contact included in the plurality of electrode contacts and partially spans a second electrode contact included in the plurality of electrode contacts, the first electrode contact being directly adjacent to the second electrode contact; and
a length of the second shape memory polymer element partially spans the second electrode contact and completely spans a third electrode contact included in the plurality of electrode contacts, the second electrode contact being directly adjacent to the third electrode contact.
9. The self-curling cochlear electrode lead of claim 6 , wherein the first shape memory polymer element and the second shape memory polymer element have different lengths in the longitudinal direction of the cochlear electrode lead.
10. The self-curling cochlear electrode lead of claim 6 , wherein:
the first shape memory polymer element has a first cross-sectional shape when viewed in a cross section that is perpendicular to the longitudinal direction of the cochlear electrode lead;
the second shape memory polymer element has a second cross-sectional shape when viewed in an additional cross section that is perpendicular to the longitudinal direction of the cochlear electrode lead; and
the first cross-sectional shape is different from the second cross-sectional shape.
11. The self-curling cochlear electrode lead of claim 6 , wherein:
the first shape memory polymer element has a first change in modulus of elasticity at the transition temperature;
the second shape memory polymer element has a second change in modulus of elasticity at the transition temperature; and
the first change in modulus of elasticity is different from the second change in modulus of elasticity.