Method of installing a spinal implant assembly

A method of installing a spinal implant assembly in a first disc space in a subject's spine, the method comprising the steps of

• providing a first spinal implant assembly, the first spinal implant assembly comprising an intervertebral device configured to be installed in a spinal disc space, the intervertebral device having a head component and a body component, the first spinal implant assembly further comprising a coupling body for coupling the head component of the intervertebral device with an elongate member, the coupling body and head component each having a longitudinal axis, wherein the head component can be received by the coupling body with the longitudinal axis of the head component at a selected angle within a predetermined range of angles relative to the longitudinal axis of the coupling body, wherein at least part of the body component of the intervertebral device is externally tapered and at least part of the body component is externally threaded;
• implanting the body component of the intervertebral device into a first disc space between a pair of adjacent vertebrae or between a vertebra and the sacrum so as to cause distraction of the disc space or at the lumbo-sacral joint;
• coupling the intervertebral device with the coupling body, before or after implanting the body component, such that the longitudinal axis of the intervertebral device is at a selected angle within a predetermined range of angles relative to the longitudinal axis of the coupling body.