Cochlear implant electrode and method of making same
View Patent ↗A cochlear stimulation lead having a pre-curved electrode array is provided. The molding process provides memory to the curved part of the lead. The lead may be made having a stylet insertion channel that extends from a slightly curved or substantially straight section and into the highly curved section of the lead. Because high compliance is desired for the lead in cochlear stimulation applications, the compliance is controlled not only by the taper at the distal end of the lead and overall lead thickness, but also by choosing the material hardness of the lead carrier/covering and employing compliant zigzagged conductor wire. In addition, differential lead compliance/stiffness can be achieved by using a stiff tubing that forms part of the stylet insertion channel.
1. An implantable lead for use with electrical stimulation, the lead comprising:
a flexible carrier having a proximal end, a distal end, a medial side and a lateral side; a distal, pre-curved lead section having memory;
a plurality of electrode contacts embedded at the distal end of the lead, which electrode contacts comprise an electrode array;
a plurality of conductor wires embedded in the carrier, each conductor wire connected to at least one electrode contact;
a longitudinal stylet insertion channel in the carrier extending into at least a part of the distal, pre-curved lead section;
an overmold which caps the opening of the stylet channel and wherein the overmold has a slit opening; and
a pin plug which has a head and a curved tail pin, which pin plug is dimensioned and configured to permit the pin plug to be inserted head first into the overmold slit opening to seal the slit opening;
wherein the overmold has a cross-configured slit for allowing an insertion stylet to be inserted into the stylet insertion channel.
2. A method of implanting an implantable stimulation lead having an insertion stylet channel with a channel opening on the lead body, the method comprising:
(a) implanting the lead using the stylet;
(b) withdrawing the stylet from the lead; and
(c) capping the insertion stylet channel opening,
wherein capping the channel opening is accomplished by taking a pin plug, having a head and curved pin, and inserting the head of the pin plug into the lead to seal the channel opening.
3. A cochlear lead system comprising:
a cochlear lead including:
a flexible carrier having a proximal end and distal end;
a stylet insertion channel incorporated into the flexible carrier; and
an electrode array placed on the distal lead end;
a pin plug for capping the insertion stylet, the pin plug having a head and tail pin with a curvature in the tail pin; and
an insertion tool which has a first end and second end, wherein the first end has a pin plug holding channel that accommodates the tail pin and holds it within the holding channel with a friction fit.
4. An implantable lead for use with electrical stimulation, the lead comprising:
a flexible carrier having a proximal end, a distal end, a medial side and a lateral side;
a distal, pre-curved lead section having memory;
a plurality of electrode contacts embedded at the distal end of the lead, which electrode contacts comprise an electrode array;
a plurality of conductor wires embedded in the carrier, each conductor wire connected to at least one electrode contact;
a longitudinal stylet insertion channel in the carrier extending into at least a part of the distal, pre-curved lead section;
an overmold which caps the opening of the stylet channel and wherein the overmold has a slit opening; and
a pin plucg which has a head and a curved tail pin, which pin plucg is dimensioned and configured to permit the pin plucg to be inserted head first into the overmold slit opening to seal the slit opening,
wherein the most distal tip of the lead that includes a subset of the electrode array is constructed as a super-flexible tip; and
wherein the super-flexible tip does not include the stylet insertion channel and which super-flexible tip has a substantially smaller thickness than the remainder of the distal lead containing the electrode array that is not super-flexible.
5. The lead of claim 4 , wherein the distal end of the lead is dimensionally tapered and sized so that the lead can be implanted no greater than about 2 turns inside the cochlear duct, which duct is the scala tympani.
6. The lead of claim 4 , wherein the overmold has a cross-configured slit for allowing an insertion stylet to be inserted into the stylet insertion channel.