A lubricant composition comprises a cycloaliphatic amine alkoxylate and a base oil selected from a polyalkylene glycol; a polyalphaolefin; a naphthenic compound; and combinations thereof; provided that the cycloaliphatic amine alkoxylate and the base oil are miscible. The medical device of this invention includes a spacer that is disposed between adjacent spinous processes and has a proximal retention member and a distal retention member, which may be rotated with respect to the proximal retention member between an initial implantation configuration and a final locked configuration. In an embodiment, cross-coupled inverters of a sense amplifier are operatively coupled between a ground node and the second supply for sensing voltage.