[Anterior decompression and fusion with n-HA/PA66 cage for the treatment of lower cervical fracture and dislocation].

OBJECTIVE

To explore the clinical effects of anterior decompression and fusion with a nano-hydroxyapatite/ polyamide 66 (n-HA/PA66) cage in treating lower cervical fracture and dislocation.

METHODS

From January 2008 to December 2010, the clinical data of 42 patients with lower cervical fracture and dislocation were retrospectively analyzed. There were 29 males and 13 females aged from 20 to 65 years old. The mean age was 46.8 years. Five cases got injuried in C3, 14 cases in C4, 12 cases in C5, 7 cases in C6 and 4 cases in C7. According to Frankel grade, 4 cases were classified in grade A, 11 cases in grade B, 13 cases in grade C, 9 cases in grade D and 5 cases in grade F. Twenty-eight cases were treated with anterior corpectomy and fusion and 14 cases with anterior discectomy and fusion. Frankel grade was used to do neurologic assessment and visual analogue scale (VAS) was used to evaluate the improvement of clinical symptoms. Segmental height and sagittal lordosis were measured by radiographs and cage location. Cage appearance and fusion status were assessed by 3D-CT images.

RESULTS

All patients were followed up for 3 to 5.2 years with an average of 4.1 years. Frankel grade had obviously improved than preoperative (Z = -4.845, P < 0.001). There were 2, 3, 11, 8, 11 cases classified in grade A, grade B, grade C, grade D and grade E respectively. At the third day after operation and latest follow-up,VAS was (2.6 +/- 1.8),(1.3 +/- 1.0) scores respectively. Both had improved than preoperative (P < 0.05). Up to the latest follow-up, there was only one patient (2.4%) with slight cage translocation (less than 2 mm), however, no cage prolapsed, or collapse, or breakage were found. Both segmental height and lordosis improved significantly after surgery (P < 0.001). And there was not significant difference in both parameters between each postoperative time points (P > 0.05). The mean distance of cage subsidence was 1.5 mm and the rate of cage subsidence (> 3 mm) was 4.8%.

CONCLUSION

The n-HA/PA66 cage can not only restore and maintain the fusion segmental height and radian, but also promote the osseous fusion and profit the radiographic assessment after operation. Thus, it was an ideal material for prop graft.