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2022, Vol. 26 ›› Issue (9): 1372-1376Design for posterior atlantoaxial internal fixation system with fusion cage based on imaging dataPan Baoshun1, 2, Fang Zhen1, Gao Mingjie1, Fang Guiming1, Chen Jinshui2, 3
Abstract: BACKGROUND: The report for posterior atlantoaxial fusion cage is few and there are still many shortages. There is a lack of fusion cages with convenient operation, large bone graft area and stable bone grafting. OBJECTIVE: To design a posterior atlantoaxial internal fixation system with fusion cage according to the anatomical characteristics and study its feasibility. METHODS: The imaging data of 100 cases (50 males and 50 females) of normal posterior arch of atlas and axis lamina were collected. The sagittal plane was used to measure the height and the thickness of the posterior arch of atlas, the slope of the axis lamina, the height of the posterior inferior margin of atlas to the upper margin of the axis, and the height of the atlantoaxial intervertebral space. The distance between the lateral margin of the pedicle of the atlas on both sides and the distance from the posterior tubercle to this line were measured to calculate the radius of the lateral margin of the posterior arch. The point which was 4 mm to the posterior tubercle was taken as the nailing point to measure the inserting length of the screw and the angle between the screw and the middle line of the posterior arch. The anatomic parameters were analyzed to design the posterior atlantoaxial internal fixation system with fusion cage. RESULTS AND CONCLUSION: (1) The height from the lower edge of the posterior arch of atlas to the upper edge of the axis spinous process was (19.07±2.73) mm. The height of the atlantoaxial intervertebral space was (6.83±2.01) mm. The slope of the axis lamina was (58.34±7.60)°. The radius of the lateral edge of the posterior arch of atlas was (26.77±2.14) mm. The height of the posterior tubercle of atlas was (10.45±1.61) mm. The thickness of the posterior tubercle of atlas was (8.12±1.57) mm. The inserting length of the posterior arch screw of atlas was (11.21±1.61) mm, and the angle was (53.34±6.30)°. The data difference between the two sides had no statistical significance. (2) According to the measurement of the imaging data, the design of the atlantoaxial internal fixation system is successful and is applied for the national patent. The atlantoaxial internal fixation system with fusion cage provides a new fixation method for posterior atlantoaxial internal fixation. Key words:atlantoaxial, imaging, anatomy, CT measurement, posterior, internal fixation, cage, posterior arch screw of atlas |