In Vivo Study Of Hat Tape Cervical Intervertebral Fusion Cage

Objective:To compare the characteristics of interbody fusion using hat type cervical intervertebral fusion Cage(HCIFC),HCIFC with hydroxyapatite(HAP) coating and HCIFC with HAP coating growth factor(GF) outside in a goat cervical spine model.Methods:Twenty-eight goats underwent C3,4 discectomy and interbody fusion in which the following were used:Group 1,HCIFC filled with autologous lilac crest graft(8 goats)(Group HCIFC);Group 2,HCIFC with hydroxyapatite(HAP) coating filled with autologous iliac bone(8 goats)(Group HAP);Group 3,HCIFC with HAP coating and growth factor(GF) outside filled with autologous lilac graft(8 goats)(Group GF). Radiography was performed preoperatively and 1,2,4,8,and 12 weeks postoperatively.At the same time,disc space height,interverbral angle, and lordosis angle were measured.After 12 weeks,the goats were killed and fusion sites were harvested.Biomechamical testing was performed in flexion,extension,axial rotation,and lateral bending to determine range of motion and the stiffness.All cervical fusion specimens underwent histomorphological analysis.Results:Significantly highest values for disc space height,intervertebral angle and lordosis angle were shown in the goats of Group GF over a 12-week period,and lowest values were shown in the goats of Group HCIFC.The stiffness of HCIFC with hydroxyapatite(HAP) coating filled with autologous iliac bone in axial rotation and later bending were statistically greater than that of the other groups.Radiographical and histomorphological evaluation showed better fusion results in GF groups than in the others. Conclusion:HAP coating can improve the fusion effect of the cervical vertebrae Cage,and GF can encourage bone fusion.