Abstract: Objective To analyze and compar the characteristics of fracture and dislocation of type B and type C cervical 7/thoracic1 by  pedicle screw combined locking plate short segment fixation and pedicle screw long segment fixation.Methods Twenty-four patients with cervical 7/ thoracic 1 fracture and dislocation were divided into group A(13 cases) and group B(11 cases) according to the inclusion criteria.Group A was treated with pedicle screw combined with locking plate for short segment fixation，while group B was treated with pedicle screw for long segment fixation.The operation time，blood loss and complications were counted.CT scan was used to observe the accuracy of pedicle screw placement.JOA score was used to evaluate the improvement of spinal cord function after surgery.NDI was used to evaluate postoperative cervical function.Independent sample t-test was used to compare the observation results of the two surgical methods.Results A case of anterior cervical hematoma was found in group A，which had been absorbed 3 months later.One case of fat liquefaction at the back of neck occurred in group A and group B，which was healed after dressing change and debridement.A total of 70 cervical and thoracic pedicle screws were placed.CT scan 1 week after surgery showed that 3 cervical 7 pedicle screws，2 cervical 5 pedicle screws and 2 cervical 6 pedicle screws，partial thread perforation of the lateral wall of the pedicle，no nerve root or vertebral artery injury.The operation time was（194.62±29.89）min and blood loss was（188.85±67.89）ml in group A，the operation time was（163.64±32.02）min and the blood loss was（244.55±42.51）ml in group B ,which were statistically significant（P＜0.05）.The improvement degree of JOA was（0.27±0.18）% in group A and（0.27±0.11）% in group B at 1week after the operation;（0.35±0.20）% in group A and（0.40±0.17）% in group B at 3 months after the operation;（0.40±0.22）% in group A and（0.42±0.16）% in group B at the last follow-up.There was no statistical significance at each time point（P＞0.05）.The NDI scores were（0.17±0.04）in group A and（0.30±0.07）in group B at 3 months after the operation;（0.09±0.03）in group A and（0.18±0.07）% in group B at the last follow-up.There was significant differences in the two time points（P＜0.05）.Conclusion Pedicle screw combined locking plate short segment fixation is complicated and traumatic，but it is conducive to postoperative limb function recovery.Pedicle screw fixation with long segments is less invasive，but it increases the risk of screw placement and has a great impact on postoperative cervical vertebral function.The anterior and posterior combined short segment fixation is preferred when the patient's physical condition is tolerable.

Key words: cervical vertebra, thoracic vertebra, fracture, dislocation, cervicothoracic junction