A transcutaneous implant tool is used to push a medical element through an incision and into a patient's subcutaneous tissue, while a fin of the tool is engaged beneath the patient's skin at the incision site. The tool preferably includes an injection rod for moving the medical element out through an opening of a bore of the tool. The fin, which is located in proximity to the opening, preferably includes a distal-facing surface that extends proximally from the opening at an acute angle with respect to a longitudinal axis of the bore; and the injection rod preferably includes a distal surface that is approximately coplanar with the distal-facing surface of the fin, when the distal surface of the rod is located in proximity to the opening of the bore.