Abstract:

Objective　To establish a novel kind of fusion model, and provide the influence of fusion by different bone mass in rats interbody fusion model.    Methods    Sixty male Sprague-Dawley rats underwent interbody fusion with bilateral iliac bone and 1-tailbone autograft into intertailbone. 0.3 cm3 autograft bone was transplanted into the fusion segments of group A and 0.2 cm3 autograft bone was transplanted into that of group B. In contrast，control group C had no bone placed. Fusion segments were removed and analyzed with manual bending and radiography at 3 and 6 weeks, respectively. Histologic analysis was performed at 6 weeks. Half were sacrifced at 3 weeks; the others were sacrifced at 6 weeks.    Results    At 3 weeks, 10%(1/10) of group A rats fused, 0%(0/10) of group B rats fused and 0%(0/10) of group C rats fused by manual palpation. At 6 weeks, 40%(4/10) of group A rats fused, 40%(4/10) of group B rats fused and 0%(0/10) of group C rats fused by manual palpation. By radiographic scoring system  ("0"no bone formation,"5"full fusion), the scores of group A，group B and group C were evaluated as（2.567±0.876），（2.467±0.878）and（0.233±0.316）at 3 weeks after operation, in contrast with（3.233±1.218）,（3.267±1.235）and（0.467±0.322）at 6 weeks after operation, respectively. From our gross observation, bone formation with interconnected bone trabecula, which existed in the fusion area of the experimental group, was verified by HE and VG staining at 6 weeks. The neogenesis of the osteoblast and the active bone remodeling with the irregular bone cement lines were seen at the higher magnification. However, there were no existence of bone fusion area in the control group, the fibers tissue is distributed instead.    Conclusions   Our research created a new animal model for spine fusion and verified the effect of quantity of bone autograft on fusion.

Key words:  Rats, Animal models, Spinal fusion, Bone transplantation