Abstract: An implantable device including a tapered body having a sidewall, an internal cavity, a first end, and a second end, the sidewall including a frusto-conical inner surface extending from the first end to the second end, the first end including a first end opening and the second end including a second end opening, a first side opening extending through the sidewall, a second side opening extending through the sidewall, the second side opening arranged diametrically opposite the first side opening, an external thread arranged helically about a central longitudinal axis of the tapered body, the external thread having a continuously decreasing outer diameter along the tapered body, a first ancillary member operatively arranged to be inserted through the first end opening and then the first or second side opening, and a second ancillary member operatively arranged to be inserted through the first end opening and then the first or second side opening.

Abstract: An implantable device comprising a tapered body having a cavity therein, an open end, a first opening arranged diametrically opposite a second opening wherein the first and second openings are proximate the open end, and a plurality of apertures within the tapered body; and, a first ancillary member operatively arranged to project outwardly from the first opening and a second ancillary member arranged to project outwardly from the second opening. A method for surgically inserting and securing the implant into the sacroiliac joint, comprising the steps of: drilling a tapered body, tapping and placing a first ancillary member to either the sacrum or the iliac bone through an open end of the tapered body, and tapping and placing a second ancillary member to either the sacrum or the iliac bone through the open end of the body.