Bone graft distribution system

A graft distribution system, comprising;

• a central beam having
• a central beam axis;
• a graft distribution channel with an entry port in fluid communication with a top exit port and a bottom exit port;
• a proximal portion having and end with the entry port, a grafting portion having the top exit port and the bottom exit port, and a distal portion;
• a transverse cross-section having a maximum dimension ranging from 5 mm to 15 mm for placing the central beam into an intervertebral space through an annular opening having a maximum lateral dimension ranging from 5 mm to 15 mm, the intervertebral space having a top vertebral plate and a bottom vertebral plate;
• a top surface with a first top-lateral surface and a second top-lateral surface;
• a bottom surface with a first bottom-lateral surface and a second bottom-lateral surface;
• a first side surface with a first top-side surface and a first bottom-side surface;
• and,
• a second side surface with a second top-side surface and a second bottom-side surface;
• and,
• a laterovertically-expanding frame configured for operably contacting the central beam to create a graft distribution system in vivo, the frame having
• a collapsed state with a transverse cross section having a maximum dimension ranging from 5 mm to 15 mm for placing the frame in the intervertebral space through the annular opening for expansion, an expanded state with a transverse cross section having a maximum dimension ranging from 6.5 mm to 18 mm for retaining the frame in the intervertebral space, the expanded state operably contacting with the central beam in the intervertebral space;
• a proximal portion having an end, a grafting portion, a distal portion having an end, and a central frame axis of the expanded state;
• a first top beam including a proximal portion having an end, a grafting portion, and a distal portion having an end, the first top beam configured for contacting the first top-lateral surface of the central beam and the first top-side surface of the central beam in the expanded state, a central axis of the first top beam at least substantially on (i) a top plane containing the central axis of the first top beam and a central axis of a second top beam and (ii) a first side plane containing the central axis of the first top beam and a central axis of a first bottom beam;
• the second top beam including a proximal portion having an end, a grafting portion having an end, and a distal portion having an end, the second top beam configured for contacting the second top-lateral surface of the central beam and the second top-side surface of the central beam in the expanded state, the central axis of the second top beam at least substantially on (i) the top plane and (ii) a second side plane containing the central axis of the second top beam and a central axis of a second bottom beam;
• the first bottom beam including a proximal portion having an end, a grafting portion, and a distal portion having an end, the first bottom beam configured for contacting the first bottom-lateral surface of the central beam and the first bottom-side surface of the central beam in the expanded state, the central axis of the first bottom beam at least substantially on (i) a bottom plane containing the central axis of the first bottom beam and the central axis of the second top beam and (ii) the first side plane;
• the second bottom beam including a proximal portion having an end, a grafting portion having an end, and a distal region having an end, the second bottom beam configured for contacting the second bottom-lateral surface of the central beam and the second bottom-side surface of the central beam in the expanded state, the central axis of the second bottom beam being at least substantially on (i) the bottom plane and (ii) a second side plane containing the central axis of the second bottom beam and the central axis of the second top beam;
• a plurality of proximal top connector elements configured to expandably connect the proximal portion of the first top beam to the proximal portion of the second top beam, the expanding consisting of a flexing at least substantially on the top plane;
• a plurality of distal top connector elements configured to expandably connect the distal portion of the first top beam to the distal portion of the second top beam, the expanding consisting of a flexing at least substantially on the top plane;
• a plurality of proximal bottom connector elements configured to expandably connect the proximal portion of the first bottom beam to the proximal portion of the second bottom beam, the expanding consisting of a flexing at least substantially on the bottom plane;
• a plurality of distal bottom connector elements configured to expandably connect the distal portion of the first bottom beam to the distal portion of the second bottom beam, the expanding consisting of a flexing at least substantially on the bottom plane;
• a plurality of proximal first side connector elements configured to expandably connect the proximal portion of the first top beam to the proximal portion of the first bottom beam, the expanding consisting of a flexing at least substantially on the first side plane;
• a plurality of distal first side connector elements configured to expandably connect the distal portion of the first top beam to the distal portion of the first bottom beam, the expanding consisting of a flexing at least substantially on the first side plane;
• a plurality of proximal second side connector elements configured to expandably connect the proximal portion of the second top beam to the proximal portion of the second bottom beam, the expanding consisting of a flexing at least substantially on the second side plane;
• a plurality of distal second side connector elements configured to expandably connect the distal portion of the second top beam to the distal portion of the second bottom beam, the expanding consisting of a flexing at least substantially on the second side plane;
• wherein,
• the framing is configured for slidably engaging with the central beam in vivo to expand the framing following placement of the central beam in the intervertebral space through the annular opening, the slidably engaging including translating the central beam into the frame from the proximal end of the frame toward the distal end of the frame in vivo;
• the translating including keeping the central beam axis at least substantially coincident with the central frame axis during the translating to create the graft distribution system in vivo through the annular opening;
• the connector elements are struts configured to have a cross-sectional aspect ratio of longitudinal thickness to transverse thickness ranging from 1:2 to 1:8, adapted to maintain structural stiffness in the laterovertically expanding frame in a direction perpendicular to the central frame axis of the expanded state of the frame;
• the graft distribution system frames a top graft-slab depth between the top surface of the central beam and the top vertebral endplate;
• and, a bottom graft-slab depth between the bottom surface of the central beam and the bottom vertebral endplate in vivo;
• and,
• the transverse cross-section of the graft distribution system in the expanded state in vivo is greater than the maximum lateral dimension of the annular opening to avoid backout.