A surgical method for positioning an extraoral bone-anchored implant device in a receiving bone site of a patient, the patient being a human being or an animal, including the following successive steps: a step of preparing the receiving bone site, a step of impacting the implant in the opening formed in the receiving bone site; a step of leveling the implant and the surrounding bone structure and making them continuous, during which the external table of the bone structure is rubbed at its part surrounding the implant, then bone fragments are positioned on the rubbed parts of the external table of the bone structure, then the bone fragments are covered with a membrane to hold the bone fragments in position, the membrane being attached to the bone structure on one side and to the implant on the other side, so as to prevent bone proliferation on the implant.