US Patent 8167841 Transcutaneous device assembly

A medical device is provided comprising a cannula having a distal portion adapted to be arranged through the skin of the subject, and an outer needle arranged coaxially with and being axially moveable relative to the cannula, the needle comprising a pointed distal end, wherein the device is adapted for advancing the cannula with the distal end of the needle projecting there from through the dermis of the subject, and subsequently retract the needle.