An implantable medical device comprising: a hermetic feedthrough comprising: an insulator comprising a first material and a through-hole; a conduit integrated with the insulator, wherein the conduit comprises a second material that is electrically conductive and that substantially fills the through-hole, the conduit extending through the insulator and being configured to conduct electricity through the insulator; and a pad coupled to an exterior surface of the insulator and configured to receive a lead coupled thereto, wherein the pad is electrically conductive and coupled to the conduit; wherein the second material includes alumina but does not include glass or constituents thereof as an additive prior to co-firing; wherein the insulator, the conduit, and the pad have a co-fired bond therebetween, wherein the co-fired bond hermetically seals the conduit with the insulator, and wherein the hermetic seal is biostable such that immersion durability is maintained after attachment of the lead to the pad; and wherein the pad comprises a first layer and a second layer overlaying at least a portion of the first layer, and the pad has a thickness of at least 50 μm; and said implantable medical device also including an encasement structure; wherein the feedthrough is coupled to the encasement structure, such that the lead may be coupled to an exterior surface of the pad external to the encasement structure. a hermetic feedthrough comprising: an insulator comprising a first material and a through-hole; a conduit integrated with the insulator, wherein the conduit comprises a second material that is electrically conductive and that substantially fills the through-hole, the conduit extending through the insulator and being configured to conduct electricity through the insulator; and a pad coupled to an exterior surface of the insulator and configured to receive a lead coupled thereto, wherein the pad is electrically conductive and coupled to the conduit; wherein the second material includes alumina but does not include glass or constituents thereof as an additive prior to co-firing; wherein the insulator, the conduit, and the pad have a co-fired bond therebetween, wherein the co-fired bond hermetically seals the conduit with the insulator, and wherein the hermetic seal is biostable such that immersion durability is maintained after attachment of the lead to the pad; and wherein the pad comprises a first layer and a second layer overlaying at least a portion of the first layer, and the pad has a thickness of at least 50 μm; an insulator comprising a first material and a through-hole; a conduit integrated with the insulator, wherein the conduit comprises a second material that is electrically conductive and that substantially fills the through-hole, the conduit extending through the insulator and being configured to conduct electricity through the insulator; and a pad coupled to an exterior surface of the insulator and configured to receive a lead coupled thereto, wherein the pad is electrically conductive and coupled to the conduit; wherein the second material includes alumina but does not include glass or constituents thereof as an additive prior to co-firing; wherein the insulator, the conduit, and the pad have a co-fired bond therebetween, wherein the co-fired bond hermetically seals the conduit with the insulator, and wherein the hermetic seal is biostable such that immersion durability is maintained after attachment of the lead to the pad; and wherein the pad comprises a first layer and a second layer overlaying at least a portion of the first layer, and the pad has a thickness of at least 50 μm; and said implantable medical device also including an encasement structure; wherein the feedthrough is coupled to the encasement structure, such that the lead may be coupled to an exterior surface of the pad external to the encasement structure.