MEDICAL ELECTRICAL LEAD AND METHOD FOR MAKING THE SAME
Publication Date: 2003-Feb-06
The IP.com Prior Art Database
A medical implantable electrical lead exhibits uniform mechanical properties throughout the entire lead body, thereby providing superior steerability and torquability features. The uniform mechanical properties are realized by making the lead body as a single unit. To make the lead body, individual wires are first coated with an insulative thermoplastic material. A multifilar coil is then wound using the coated wires to achieve a desired outer diameter, inner diameter, and pitch. The multifilar coil is then coextruded in a jacket of insulative thermoplastic material. The insulative thermoplastic material has a melting temperature that is lower than the melting temperature of the thermoplastic material that coats the individual wires. A mandrel may be placed in the inner diameter of the coil during the coextrusion process to ensure the patency of the inner lumen. The coextruded lead is placed in a fixture to determine the location of the wires for exposure for subsequent electrode connection. The outer jacket insulation is removed using a suitable removal process, and ring electrodes are positioned along the lead body so as to align with the locations where the insulation has been removed. The electrodes are then electrically and mechanically bonded to the lead body. Finally, any voids or gaps between the ring electrodes and the outer jacket insulation are filled with a suitable thermoplastic. The above process results in a single unit construction that provides a torque ratio that approaches 1:1.