Experimental Study Of Absorbable Enhanced β-tricalcium Phosphate Cervical Cage In Goats

ObjectiveUse anterior cervical surgery of goats as model to evaluate the enhanced β-tricalcium phosphate (P-TCP) cervical cages through imaging and histological observation, hoping to provide the basis for further improving and clinical application.MethodsA total of362-year-old goats were randomly divided into3groups:group A, autogenous tricortical iliac crest group, n=12; group B, P-TCP cervical cage group, n=12; and group C, P-TCP cervical cage combined bone morphogenetic protein (BMP)group, n=12. Then each group was subdivided into3months’ groups (A1、B1、C1group) and6months’groups (A2、B2、C2group), respectively. Sacrifice the goats at3months and6months as plan. Evaluate the ability of the cages in maintaining intervertebral height though X-ray. Perform CT plane scanning and sagittal2D reconstruction to evaluate fusion situation. Then the C3/4segment was isolated and sectioned to create sagittal slices. Histomorphological analyses were performed to evaluate fusion by the measurement of new bone area (NBA), residual material area (RMA), depth of tissue penetration (DTP), material degradation rate(MDR) and the length of contact of new bone and the density part of the cage (CBDP).ResultsOver a3months period, the β-TCP cervical cage showed higher values for disc space height compared with the autogenous iliac bone graft. Additionally, the fusion rate of group A and group C were similar. While the fusion of group B was the worst. Histologically, the better performance of NBA, RMA, RPA, DTP, MDR, CBDP were found in the β-TCP cervical cage+BMP group.Over a6months period, group B and group C were similar in values for disc space height; the fusion rate of group A and group C were similar, and better than group B. The better histological performance of NBA, RMA, DTP, MDR, CBDP were found in the β-TCP cervical cage+BMP group.Compare the performance between3months’groups and6months’ groups, the disc space height and fusion rate vary statistically. The3months’ groups show better results of NBA, RMA, DTP, MDR and CBDP, while the diversity of CBDP is not statistical.ConclusionsThe enhanced (3-TCP bioceramic cervical cages can provide good mechanical support for anterior cervical surgery. The spongy part of the cages degrade gradually in pace with new bone generation; The surrounding densest part can still maintain the structure6months after operation. The β-TCP cervical cage alone can’t achieve equal fusion rate as autogenous tricortical iliac crest group. The combination of the cage and BMP can increase new bone’s infiltration into the spongy section, promote the contact of new bone and the cage’s density part, and thus improve fusion rate.