Spine disc replacement with compliant articulating core

摘要

An intervertebral implant can include a pair of endplates between which is coupled a bag that is filled or is fillable with small beads or particles having smooth exterior geometries. The bead sack implant allows for articulation about various centers of rotation without a predefined neutral position.

主权项

1. An expandable intervertebral implant assembly configured for insertion along an insertion direction into an intervertebral space defined between a superior vertebral body and an inferior vertebral body, the expandable intervertebral implant comprising:
a superior endplate configured for disposition adjacent to the superior vertebral body; an inferior endplate spaced from the superior endplate along a transverse direction that is substantially perpendicular to the insertion direction, the inferior endplate configured for disposition adjacent to the inferior vertebral body; at least one securement member that projects from at least one of the superior and inferior endplates along the transverse direction, the at least one securement member configured to engage the respective superior and inferior vertebral bodies; and a compliant bag coupled between the superior and inferior endplates, the compliant bag including an outer wall, the outer wall defining a superior coupling surface and an inferior coupling surface spaced from the superior coupling surface along the transverse direction, the superior coupling surface coupled to the superior endplate, the inferior coupling surface coupled to the inferior endplate, the outer wall further defining an internal void, the internal void of the compliant bag configured to receive a plurality of discrete particles therein so as to expand the implant along at least the transverse direction from a first configuration into second expanded configuration, wherein when 1) the expandable implant is disposed between the vertebra bodies, 2) the plurality of discrete particles are received in the internal void, 3) the expandable implant is in the second expanded configuration, and 4) the at least one securement member is engaged with the respective at least one of the first and second vertebral bodies, the expandable implant provides a resistance to relative rotation of the superior and inferior endplates with respect to each other about at least a transverse axis that is substantially aligned with the transverse direction.