The invention relates primarily to the use of an endosteal guide pin for preparing a guide path for the implantation of a pedicle or orthopaedic screw, the pin (1) having a head (2) intended to be provisionally implanted in a bone (16), and a guide rod (4), coaxial with and rigidly secured to the head (2), ending in a free end (5) intended to be at least level with the skin surface (17) of the patient when the pin (1) is in the implanted position in the bone (16), wherein the pin (1) has a first coupling means (6) intended at least to secure it to and release it from at least one portion of a positioning trocar (8), and a second coupling means (6) intended at least to secure it to a removal trocar (8). The invention also relates to a trocar (8) for positioning a guide pin (1), which trocar incorporates said guide pin (1), and to a trocar for removing said pin (1).
