An intervertebral cage with an outer frame, an open inner core region and a porosity gradient within the outer frame is provided. The outer frame includes a posterior wall, an anterior wall, a pair of side walls extending between the posterior wall and the anterior wall and the porosity gradient may comprise at least one of: a decreasing average pore diameter in a direction from an outer surface to an inner surface of at least one of the pair of side walls； an increasing average pore diameter in a direction from an outer surface to an inner surface of at least one of the pair of side walls； a decreasing average pore diameter in a direction from an upper surface to a lower surface of at least one of the side walls； and an increasing average pore diameter in a direction from an upper surface to a lower surface of at least one of the side walls.
