US Patent 10143565 Unidirectional dynamic interbody fusion device and method of use

An interbody fusion device includes a top member, a base member, and an expansion member. The top member includes a first bone-engaging side and a threaded opening. The base member is received by the top member and includes a second bone-engaging side and an open cavity aligned with the threaded opening of the top member. The expansion member is disposed within the open cavity for rotation about an axis. The expansion member includes a threaded portion threadably engaged with the threaded opening. Rotation of the expansion member translates the first bone-engaging side away from the second bone-engaging side along the axis.