[Application of n-HA/PA66 composite artificial vertebral body in anterior reconstruction of lower cervical spine fracture and dislocation].

OBJECTIVE: To initially evaluate the application of artificial vertebra of n-HA/PA66 in anterior reconstruction of lower cervical spine fracture and dislocation.

METHODS: In this study, 84 patients with lower cervical spine fracture and dislocation received anterior cervical discectomy, spinal canal decompression or subtotal corpectomy, spinal canal decompression and reconstruction by n-HA/PA66 composite artificial vertebral body combined with plate instrumentation. Neurological function was followed up by improvement rate of Frankel and situations of the supporting body was observed by X ray and 3D-CT in 3, 12, 24 months postoperatively. The intervertebral height, physical arc (reflected by Cobb angle) and the locations and fusion rate of the supporting body were assessed in order to evaluate the stability of the cervical spine and alignment improvements.

RESULTS: All the patients underwent operation successfully and were followed up for 6 to 24 months with an average of 12 months. The preoperative symptoms were improved to varying degrees. Imaging studies showed that in all cases graft fusion were achieved, and cervical alignments, intervertebral height, cervical spine stability and the locations of the artificial vertebral body were well maintained. No displacement and subsidence of the artificial vertebral body occurred. Postoperative immediate intervertebral height (2.4 ± 0.2) cm, preoperative intervertebral height (1.9 ± 0.1) cm, comparisons of the two groups was statistically significant (q = 2.48, P < 0.001). The immediate, 3 month, 1 year, 2 year period follow-up group intervertebral height was not statistically significant (P > 0.05). Preoperative Cobb angle was 9.8° ± 1.2°, postoperative immediate Cobb angle was 16.6° ± 1.2°, comparisons of the two groups was statistically significant (q = 14.25, P < 0.001). The immediate, 3 month, 1 year, 2 year period follow-up group Cobb angle was not statistically significant (P > 0.05).

CONCLUSIONS: n-HA/PA66 artificial vertebral body can provide early cervical spine support and stability and effectively maintain the biological alignment and cervical intervertebral height. It has high rate of graft fusion and is convenient to observe by X-ray. Therefore, n-HA/PA66 can be taken as an ideal graft for anterior lower cervical spine fracture and dislocation operation, but further follow-up study is still required to evaluate the long-term effects.