An implant that has a predefined ratio of load bearing surface area to the overall size of the implant body and specifically to the surface area of a centrally located opening of a vertical aperture which connects to a center void area or passage defined by the implant body shape. This invention discloses a critical ratio or balance between loading of contained graft material through the hollow center or central passage of the implant and the implant's frictional load bearing or contact area with e.g., adjacent vertebral bones. Application of this invention to a spinal implant provides an improved integration and integration rate of the graft material or the fusion of the adjacent vertebral bone structures. The ratio between implant load bearing surface area and implant central opening area maximizes implant internal volume and allows a large passage disposed medial laterally to allow for radiographic verification of fusion growth.