ObjectiveTo evaluate the effect of poly-amino acid/nano-hydroxyapatite/calcium sulfate (PHC) Cage in lumbar interbody fusion of the goat. MethodsEighteen mature female goats (weighing 29-33 kg) were divided into 3 groups randomly: PHC Cage group (group A), titanium Cage group (group B), and ilium group (group C). A left extraperitoneal approach was used to establish the animal model of discectomy and interbody fusion with Cage or ilium. The general situation was observed for 24 weeks after operation. X-ray films were taken to measure disc space height (DSH) before operation and at 4, 12, and 24 weeks after operation. CT three dimensional reconstuction was performed at 24 weeks after operation to evaluate the interbody fusion according to modified Brantigan grading. The specimens of L3, 4 were harvested for mechanical test, histological, and scanning electron microscope (SEM) observation at 24 weeks after operation. ResultsAll goats survived to the end of experiment. DSH at 4 weeks after operation increased when compared with preoperative one in each group, and then decreased;DSH was significantly lower at 12 and 24 weeks after operation than preoperative one in group C (P<0.05). There was no significant difference in DSH among 3 groups at preoperation and 4 weeks after operation (P>0.05);at 12 and 24 weeks after operation, DSH of groups A and B was significantly higher than that of group C (P<0.05), but no significant difference was found between groups A and B (P>0.05). CT three dimensional reconstuction showed that bony fusion was obtained in all goats of groups A and C, and in 3 goats of group B;according to modified Brantigan grading, the scores of groups A and C were significantlly higher than that of group B (P<0.05), but no significant difference between groups A and C (P>0.05). The biomechanical test showed that there was no significant difference in range of motion between group A and group B (P>0.05), which were significantly lower than that of group C (P<0.05). Microscopy and SEM observations showed that the interface between the Cage and vertebral body in group A was compact without obvious gap, and most conjunctive region was filled with osseous tissue;the interface was filled with soft tissue, and the connection was slack with obvious gap in some region in group B;the interface connection was compact, most region was filled with osseous tissue in group C. ConclusionThe interbody fusion with PHC Cage is effective in goat lumbar interbody fusion model. The interface connection is compact between the Cage and the host bone followed by micro-degradation of PHC Cage, but the long-term degradation need further observation.
ObjectiveTo discuss the early effectiveness of polyaminoacid/nano-hydroxyapatite/calcium sulfate (PAA/HA/CS) Cage (PHC Cage) in lumbar fusion surgery. MethodsThirty cases undergoing lumbar fusion of single segment between March and September 2014 were enrolled in this study. The patients were randomly divided into the trial group (n=20) and the control group (n=10). The PHC Cage was implanted in the trial group, while the polyetheretherketone (PEEK) Cage was implanted in the control group. The patients of 2 groups mainly presented lumbocrural pain and lower limb radiation pain or numbness. There was no significant difference in gender, age, type, affected segment, disease duration, preoperative intervertebral height, the lordosis angle of fusion segments, and the Oswestry Disability Index (ODI) between 2 groups (P > 0.05). Lateral lumbar X-ray films and three dimensional CT were taken preoperatively and at 1 week and 3, 6, and 12 months postoperatively. The intervertebral height and the lordosis angle of fusion segments at 1 week and 3, 6, and 12 months after operation and ODI at 3, 6, and 12 months after operation were measured; and the bone graft fusion rate was evaluated according to Brantigan criteria. ResultsThere was no significant difference in operation time, intraoperative blood loss, and the amount of autologous blood transfusion between 2 groups (P > 0.05). Healing by first intention was obtained in 30 cases. All patients were followed up 12 months. The intervertebral height of fusion segments, the lordosis angle of fusion segments, and ODI at each time point after operation were significantly improved when compared with preoperative ones (P < 0.05). The ODI showed significant difference between 3 months and 6, 12 months (P < 0.05), but there was no significant difference between the other time points after operation (P > 0.05). There was no significant difference in the intervertebral height and the lordosis angle of fusion segments between groups at different time points (P > 0.05). There was no significant difference in the above indexes between the trial group and the control group at each time point (P > 0.05). At last follow-up, 5 cases were rated as Brantigan grade E, 13 cases as grade D, and 2 cases as grade C in the trial group; 4 cases were rated grade E, 5 cases as grade D, and 1 case as grade C in the control group. The bone fusion rate was 90% in 2 groups. ConclusionThe PHC Cage can effectively restore and maintain the disc height of fusion segment, normal sequence and biomechanical stability of the lumbar spine. The PHC Cage is similar to the PEEK Cage and has good clinical outcome in short-term follow-up.