Electrode lead assembly for implantable devices and method of preparing same

The method of encapsulating a coiled electrical conductor within an insulating sleeve for preparation of an implantation electrode lead assembly for coupling an electrical stimulator pulse generator to an electrode tip means in contact with an internal organ to be stimulated, said method comprising:

• (a) selecting a first tubular element of semi-conductive silicone rubber having a resistivity of below about 130 ohm-cm., with said first tubular element having a normal internal diameter which is less than the external diameter of the coiled electrical conductor to be encapsulated;
• (b) immersing said first tubular element in a solvent for expanding said tubular element until the internal diameter thereof exceeds the external diameter of said coiled electrical conductor, and inserting said coiled electrical conductor into said tubular element while expanded;
• (c) removing the solvent from said first tubular element for compression thereof;
• (d) selecting a second tubular element, said second tubular element being an insulative silicone rubber having a normal internal diameter less than the outer diameter of said first tubular element;
• (e) immersing said second tubular element into a solvent for the purpose of expanding said second tubular element until the internal diameter thereof exceeds the outer diameter of said first tubular element, and inserting said first tubular element into said second tubular element while said second tubular element remains expanded;
• and
• (f) removing solvent from said second tubular element so as to cause said second tubular element to return to its normal dimentional condition, thereby compressively retaining said first tubular element and coiled electrical conductor therewithin.