An implantable medical device with a ceramic enclosure has a novel multi-layered ceramic feedthrough substrate in place of a prior art glass-to-metal feedthrough substrate, leading to lower costs and a higher feedthrough density. Use in a metal enclosure is also disclosed. ...http://www.google.co.uk/patents/US5782891?utm_source=gb-gplus-sharePatent US5782891 - Implantable ceramic enclosure for pacing, neurological, and other medical applications in the human body 
