[In vivo experimental study of hat type cervical intervertebral fusion cage].
OBJECTIVE
To compare the characteristics of interbody fusion achieved using hat type cervical intervertebral fusion cage (HCIFC) with those of an autologous tricortical iliac crest graft, Harms cage and Carbon cage in a goat cervical spine model.


METHODS
Thirty-two goats underwent C(3, 4) discectomy and fusion in which the following were used: Group 1, autologous tricortical iliac crest bone graft (8 goats); Group 2, Harms cage filled with autologous iliac crest graft (8 goats); Group 3, Carbon cage filled with autologous iliac bone (8 goats); Group 4, HCIFC filled with autologous iliac graft (8 goats). Radiography was performed pre- and postoperatively and after 1, 2, 4, 8, and 12 weeks. At the same time points, disc space height, intervertebral angle, and lordosis angle were measured. After 12 weeks, the goats were killed and fusion sites were harvested. Biomechanical testing was performed in flexion, extension, axial rotation, and lateral bending to determine the stiffness and range of motion. All cervical fusion specimens underwent histomorphological analysis.


RESULTS
One week after operation, the DSH, IVA and LA of HCIFC and Carbon cage were statistically greater than those of autologous iliac bone graft and Harms cage. Significantly higher values for disc space height, intervertebral angle and lordosis angle were shown in cage-treated goats than in those that received bone graft over a 12-week period. The stiffness of Harms cage in axial rotation and later bending were statistically greater than that of other groups. Radiographic and histomorphologic evaluation showed better fusion results in cage groups than in autologous bone group.


CONCLUSIONS
HCIFC can provide a good intervertebral distractability and enough biomechanical stability for cervical fusion.
Gu
Yu-tong
YT
Department of Orthopaedics, Zhongshan Hospital of Fudan University, Shanghai 200032, China. gyt633@sohu.com
Jia
Lian-shun
LS
Chen
Tong-yi
TY
Qi
Jin
J
Wang
Jun
J
Cui
Shu-fang
SF
Li
Xiao-hui
XH
D000818:Animals; D001696:Biomechanical Phenomena; D016025:Bone Transplantation / Q000379:methods; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006041:Goats; D007085:Ilium / Q000637:transplantation; D016268:Internal Fixators; D008297:Male; D008422:Materials Testing; D011859:Radiography; D011897:Random Allocation; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*; D014182:Transplantation, Autologous