OBJECTIVE
To study the clinical effects of the artificial vertebral body of the biomimetic nano-hydroxyapatite/ polyamide 66 (n-HA/PA66) composite for the structural reconstruction and the height restoring of the vertebral body in the thoracolumbar fractures by the anterior surgical procedures.
METHODS
From December 2003 to January 2006, 42 patients with thoracolumbar fractures received the anterior surgical procedures to decompress and reconstruct the spinal vertebral structure with the artificial vertebral body of the n-HA/PA66 composite. Among the patients, there were 28 males and 14 females, aged 17-67 years, averaged 43.6 years. The thoracolumbar fractures developed at T12 in 5 patients, at L1 in 17, at L2 in 14, and at L3 in 6. The height of the anterior border of the vertebral body amounted to 29%-47% of the vertebral body height, averaged 40.6%. The Cobb angle on the sagittal plane was 21-38 degrees averaged 27.6 degrees. According to the Frankel grading scale, the injuries to the nerves were as the following: Grade A in 7 patients, Grade B in 19, Grade C in 8, Grade D in 6, and Grade E in 2.
RESULTS
All the 42 patients were followed up for 6-25 months. Among the patients, 36 were reconstructed almost based on the normal anatomic structure, and 6 were well reconstructed. The mean height of the anterior border of the vertebral body was 40.6% of the vertebral body height before operation but 91.7% after operation. And the reconstructed height of the vertebra was maintained. The mean Cobb angle on the sagittal plane was 27.6 degrees before operation but 13.4 degrees after operation. All the patients had a recovery of the neurological function that had a 1-grade or 2-grade improvement except 7 patients who were still in Grade A and 2 patients who were in Grade D. The implant was fused 3-5 months after operation. No infection, nail break, bar/ plate break or loosening of the internal fixation occurred.
CONCLUSION
The artificial vertebral body of the biomimetic n-HA/PA66 composite can effectively restore the height and the structure of the vertebra, can be fused with the vertebral body to reconstruct the spinal structural stability effectively, and can be extensively used in the clinical practice.