Medical device comprising an electrode and a light source

Medical device for insertion into soft tissue having a front (distal) end and a rear (proximal) end, comprising:

• a micro electrode;
• a micro light source;
• a stiffening element comprising one of:
• a) a material dissolvable or degradable in aqueous body fluid in an amount sufficient to make the stiffening element dissolve or collapse in contact with aqueous body fluid;
• b) a material swellable in aqueous body fluid to form a transparent gel;
• a coat of a flexible non-conducting polymer material on the stiffening element preventing or at least delaying contact between the electrode and soft tissue upon collapse or swelling of the stiffening element, the coat having a distal opening allowing light emitted from the light source to leave the device upon said collapse or dissolution or swelling,
• a base disposed at the rear end of the device.