Resorbable posterior spinal fusion system

An implant for containing a bone-graft or growth material and facilitating posterior lateral fusion of at least two vertebrae following an in vivo surgical procedure, the implant having a pre-implant configuration which is defined as a configuration of the implant immediately before the implant is placed into contact with the at least two vertebrae, the implant comprising:

• a substantially-smooth membrane of resorbable polymer base material having a first substantially-smooth side, a second substantially-smooth side, and a perimeter edge joining the first substantially-smooth side to the second substantially-smooth side, wherein first and second points are disposed on opposing sides of the perimeter edge, the substantially-smooth membrane of resorbable polymer base material comprising a single layer of resorbable polymer base material between the first substantially-smooth side and the second substantially-smooth side, the single layer of resorbable polymer base material having a substantially uniform composition and being adapted to be rolled to bring the first point into proximity with the second point to thereby form a rolled layer of resorbable polymer base material;
• a plurality or apertures disposed in the single layer of resorbable polymer base material, the plurality of apertures being substantially uniformly distributed over at least a portion of both the first substantially-smooth side and the second substantially-smooth side of the single layer of resorbable polymer base material, each of the plurality of apertures of the implant when the implant is in the pre-implant configuration having a width which is between about 500 microns and about 3000 microns and which defines an isolated, non-intersecting, fluid-flow path from the first side to the second side;
• and
• a window formed in the substantially-smooth membrane of resorbable polymer base material, the window having a width that is greater than about 5 mm when the implant is in the pre-implant condition, the window being sized and shaped to accommodate a portion of a transverse process of one of the two vertebrae into the rolled layer of resorbable polymer base material when the rolled layer of resorbable polymer base material is placed into contact with the at least two vertebrae;
• wherein a thickness of the single layer of resorbable polymer base material, measured between the first substantially-smooth side and the second substantially-smooth side, is between about 0.5 mm and about 3 mm when the substantially-smooth membrane of resorbable polymer base material is in the pre-implant configuration;
• wherein each of the plurality of apertures of the substantially-smooth membrane of resorbable polymer base material immediately after implanting of the substantially-smooth membrane of resorbable polymer base material, has a diameter sufficient in size to allow a proliferation of vasculature and connective tissue cells, derived from adjacent soft tissues, to permeate through the aperture and substantially into a center of the rolled layer of resorbable polymer base material;
• wherein the implant comprises a configuration and strength sufficient to prevent prolapse of adjacent soft tissues into the center of the layer of resorbable polymer base material, when the single layer of resorbable polymer base material is rolled and placed into contact with the at least two vertebrae;
• and
• wherein the substantially-smooth membrane of resorbable base material is adapted to be resorbed into a mammalian body within a period of approximately 18 to 24 months from an initial implantation of the implant into the mammalian body.