An experimental study on the safety of screwp lacement in anterior atlantoaxial transarticular screw fixation

ZHENG Yu; CAI Xian-hua; DANG Jian-jun; JIN Hong-bin; HUANG Wei-bing; ZENG Xiao-hua; YANG Yu-heng

doi:10.3969/j.issn.2095-252X.2014.12.013

Abstract：Objective To investigate the relative safety range of screw placement in anterior atlantoaxial transarticular screw ifxation and to provide more anatomical data for Chinese surgeons. Methods The key point of anterior atlantoaxial transarticular screw ifxation was 4 mm over the junction of the inferior edge of the atlantoaxial anterior arch and its lateral edge. A surgery model was established in cervical specimens from 6 embalmed human bodies, and the operation of screw placement was repeated. The safety range measured by multislice computed tomography ( MSCT ) 3 D reconstruction was further clarified, so as to be used as a guide in clinical application. Results No screws perforating the superior articular surface of the atlas were found. It was ( 2.80±0.12 ) mm from the screw tip to the superior articular surface of the atlas. Among the 3 multi-planar reconstruction ( MPR ) transverse sections of the superior edge of the transverse foramen of the atlas and the superior edge and inferior edge of the atlantoaxial joint surface, the closest distance was ( 6.51±0.32 ) mm from the screw of the superior edge of the atlantoaxial joint surface ( transverse section B ) to the spinal canal. The closest distance was ( 5.52±1.22 ) mm from the screw of the superior edge of the atlantoaxial joint surface ( transverse section C ) to the vertebral artery, and the distance was ( 2.80±0.12 ) mm from the screw to the superior articular surface of the massa lateralis atlantis. No injuries in the spinal cord, vertebral artery or atlantooccipital joint were found. Conclusions It is feasible and safe in clinical practice to set the screw according to Lu’s standard and to take the relevant anatomical data obtained by AW 3 D software of GE RA600 PACS workstation as the experimental basis, which has been successfully veriifed.