An apparatus for tracing leaks in vivo in an implanted electrode device, said electrode device including an electrode cable containing an elongate, flexible conductor having an extent covered by insulation, in which a leak may exist, and having an interior forming a channel having a channel diameter and a distal end, said apparatus comprising:
- a tubular, flexible body having an exterior diameter smaller than said channel diameter so as to be insertable in said channel substantially to said distal end of said channel, said body having an opening communicating with said channel;
- and
- a container in fluid communication with said body and containing fluid introducible into said body and, through said opening, into said channel and said container causing said fluid in said channel to exhibit a radial fluid pressure greater than an external pressure acting on an exterior of said cable and thereby forcing said fluid through any leak which may exist in said insulation.