The ornamental design for a medicalfasteningdevice, as shown and described.
FIG. 1 is a right perspective view of the medical fastening device with its legs in an open configuration, the left perspective view being a mirror image thereof;
FIG. 2 is a top view of the medical fastening device with its legs in the open configuration, the bottom view being a mirror image thereof;
FIG. 3 is a right perspective view of the medical fastening device with its legs in a closed configuration, the left perspective view being a mirror image thereof; and,
FIG. 4 is a top view of the medical fastening device with its legs in the closed configuration, the bottom view being a mirror image thereof.