A surgical implant includes a body portion, a first tier, and a second tier. The first tier is attached to an upper surface of the body portion, and the second tier is attached to a lower surface of the body portion. Each of the upper surface and the lower surface of the body portion includes channels formed therein. The first tier includes a first layer including a plurality of first slats and a second layer including a plurality of second slats, where the plurality of first slats and the plurality of second slats intersect one another to form openings therebetween. The second tier includes a third layer including a plurality of third slats and a fourth layer including a plurality of fourth slats, where the plurality of third slats and the plurality of fourth slats intersect one another to form openings therebetween. When the first tier and the second tier are attached to the body portion, a passageway is formed through the openings formed in the first tier to the channels in the upper surface of the body portion, and a passageway is formed through the openings formed in the second tier to the channels in the lower surface of the body portion.
