Biomechanical evaluation of three-dimensional stability of anterior approach screw fixation through C2 vertebral body to C1 lateral mass / 中国骨伤

<p><b>OBJECTIVE</b>To determine the three-dimensional stability of C1-C2 after anterior approach screw fixation through C2 vertebral body to C1 lateral mass for C1-C2 instability or dislocation.</p><p><b>METHODS</b>The three-dimensional range of motion of atlantoaxial joint were measured in 16 human cadaveric specimens under four conditions: the intact state (1st group), odontoid fracture of type II (2nd group), instrumentation with posterior C1-C2 trans-articular screw fixation (Magerl technique) (3rd group) and anterior approach screw fixation through C2 vertebral body to C1 lateral mass (4th group) respectively.</p><p><b>RESULTS</b>There was generally significant difference between 1st group and other groups and between 2nd group and other groups by statistics analysis (P < 0.001). Range of motion significantly decreased in 3rd group and 4th group in all directions. There was generally no significant difference between the two methods by statistical analysis (P > 0.05).</p><p><b>CONCLUSION</b>Anterior approach screw fixation through C2 vertebral body to C lateral mass provides satisfied stability. It provides the equivalent effect to Magerl technique. It is a kind of reliable surgery choice for the treatment of instability or dislocation of C1-C2 joint.</p>

Treatment of thoracolumbar burst fractures with bioactive artificial vertebrae of nano-hydroxyapatite and polymide 66 / 中华创伤杂志

Objective To investigate the efficacy of the bioactive artificial vertebrae of a nano- hydroapatite crystals and polyamide 66 composite(n-HA/PA66)to restore the height and architecture of thoracolumbar burst fracture.Methods From December 2003 to February 2006,38 patients(29 males and 9 females)with a mean age of 35.6 years(17-63 years)were treated surgically through anterior ap- proach for decompression and implanted with the bioactive artificial vertebrae of n-HA/PA66 composite to reconstruct the structure of the thoracolumbar burst fractured vertebra.Results All the patients were successfuly followed-up for an average of 8 months,ranging from 6 to 21 months.The bioaetive artificial vertebrac of n-HA/PA66 composite were fused with the receptor bone 3-4 months after operation.The neu- rological function of the patients was restored partially or completely.The thoracolumbar spine was stable during physical examination and the height of thoraeolumbar burst fractured vertebrae that had been restored did not changa during the follow-up.Conclusions Our results show the bioaetive artificial vertebrae of n-HA/PA66 can restore the height and structure of thoracolumbar burst fractured vertebrae and reconstruct the structure of the tboraeolumbar vertebrae effectively,indicating that the bioaetive artificial vertebrae of n- HA/PA66 can be used extensively in clinical spinal surgery.