An implantable medical device is provided which has a housing of an elongate form to minimize a size of an incision required for implantation. The stylus has an elongated housing and a cap. A support of a substantially flexible material positioned is around the sidewall portion. The fixing portion is received in the housing, and includes a block defining a slot with with the tab extending therethrough, an light source for illuminating the light guide plate, a switch to switch on or off the light source and the electronic device. A process using the system is further disclosed.