A method for constructing an instrument with a covered bore for subcutaneous implantation is provided. An incising body is formed by defining a non-circular coaxial bore and sharpening a cutting edge extending from a bottom distal end beyond the opening of the coaxial bore and affixing an attachment point at a top distal end. A plunger is constructed sized to fit within the coaxial bore. The plunger is inserted in the bore of the incising body. A cover is affixed to the attachment point, wherein the cover extends down to the bottom distal end and, when closed, the cover encloses the opening proximal to the cutting edge.