IMPLANT WITH CRITICAL RATIO OF LOAD BEARING SURFACE AREA TO CENTRAL OPENING AREA

摘要

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 implants frictional load bearing or contact area with e.g., adjacent vertebral bones. Application of this invention to, for example, 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. A ratio-guided implant of this invention also advantageously positions the load bearing surfaces of the implant for support e.g., at the apophyseal rim of the vertebrae. An implant that has a predefined ratio of load bearing surface area to the overall size of the implant body and a centrally located passage that allows for balance between loading of contained graft material and frictional contact area with the bones which improves the integration rate of this graft material into the fusion of the two bone structures. As it taught by Wolff's Law stimulation of osseous tissues can promote changes in the composition and structure of the tissues. This ratio between the sizes of these features maximizes the internal volume and follows an intended percentage of area and also allows for a large passage medial laterally to allow for radiographic verification of fusion growth. The ratio guided design also positions the load bearing surfaces in the most beneficial region for support as they are positioned at the apophyseal rim of the vertebrae. Alternates based on implant design, quantity used per procedure and location within the spinal column.