An interbody spinal device for insertion into an intervertebral disc space of a vertebrate animal, where the device is adapted to rotate within the intervertebral disc space upon insertion. The invention also provides a method of distracting and/or maintaining two adjacent vertebrae of a vertebrate animal until the two adjoining vertebrae are fused, the method comprising: (a) creating an intervertebral disc space between the two adjacent vertebrae through an aperture; and (b) inserting an interbody spinal device through an aperture into the intervertebral disc space.