Screw path of pedicle of upper thoracic spine and anatomical positions of prevertebral key structures:computed tomography evaluation / 中国组织工程研究

ABSTRACT

BACKGROUND:The structure surrounding upper thoracic spine is complicated. Transverse diameter of pedicle was relatively smal . There were important organs in front of the vertebral body. Screws deviated from axis or screws were too long. The safety and effectiveness of screw implantation were not implemented. It is necessary to understand the key structure of surroundings. OBJECTIVE:To analyze the relationship of anatomic position between the axis of screw of pedicle of upper thoracic spine and key adjacent structure of the vertebral body. METHODS:A total of 30 healthy adult volunteers received T 1-T 4 pedicle axis paral el to CT scans. The positions of esophagus, trachea position, aortic arch, carotid and vertebral arteries were observed when the pedicle screw was implanted along the pedicle axis. The shortest distance on both sides of a vertebral pedicle axis from these structures was measured. Paired t-test was utilized for analysis. RESULTS AND CONCLUSION:240 measurement parameters were analyzed. The distance from the left pedicle axis on T 1-3 to esophagus was smal , and the left pedicle on T 2 was minimal. The distance from the right pedicle axis on T 2-4 to trachea was smal . The distance from right pedicle axis on T 3 , T 4 to right main bronchus was smal . Carotid and vertebral artery did not show the risk of injury. 62%of the patients were in the aortic arch on T 4 plane, and no risk of damage was found. These results indicated that the left pedicle screws were easy to damage the esophagus, and the right pedicle screw was easy to damage trachea. Carotid artery, vertebral artery and aortic arch were not easy to be damaged. The anatomic position of easily damaged structure could be identified by careful analysis of CT data before screw implantation in the pedicle of upper thoracic spine.