UNLABELLEDA new kind of Interbody Cage made of multi-amino acid copolymer/tri-calcium phosphate (MAACP/TCP) composite was designed, and the purpose of this study was to evaluate immediate stability of MAACP/TCP Cage in a goat cervical spine model (C3-4). After the motion segment C3-4 was tested intact, 27 goat cervical spines were divided into three groups randomly. There were four groups group A. MAACP/TCP Cage group (n = 9), group B2 titanium Cage group (n = 9), group C2 autologous tricortical iliac crest bone group (n = 9) and group D: intact group (n = 27). Different Cage groups were implanted after complete discectomy (C3-4) was performed. Then they were tested in flexion, extension, axial rotation, and lateral bending with a nondestructive stiffness method. The range of motion (ROM) and relative stiffness were calculated and compared between groups. In comparison to the intact motion segment, MAACP/TCP Cage showed a significantly (P < 0.05) lower ROM and a significantly (P < 0.05) higher relative stiffness in flexion and lateral bending. In comparison to the tricortical iliac crest bone graft, MAACP/TCP Cage showed a significantly (P < 0.05) lower ROM and a significantly (P < 0.05) higher relative stiffness in extension, flexion and lateral bending. There was no significant (P > 0.05) difference in the ROM and relative stiffness between MAACP/TCP Cage and titanium Cage in extension, flexion and lateral bending. In comparison to titanium Cage, MAACP/TCP Cage showed a significantly (P < 0.05) higher ROM and a significantly (P < 0.05) lower relative stiffness in rotation.

CONCLUSIONMAACP/TCP Cage can provide enough immediate stability for cervical interbody fusion in a goat cervical spine model.