The Study Of Atlanto-axial Vertebral Arch After Lateral Mass Screws Technology With The Measurement Of Three-dimensional CT And Anatomy

BackgroundThe vital center of the spine is Atlanto-axial vertebral, which can aslo be called the 1st,2nd cervical, the spinal cord and its special position, adjacent to the complex structure. Atlanto-axial dislocation or vertebral instability, can endanger patient’s life. The inefficiency of conservative treatment, atlas and axis posterior (after bow, lateral mass screw fixation) is a common surgical procedure. Differences of atlanto-axial vertebral measurement data at home and abroad, affect the accuracy and security of the clinical nailing. So the accuracy of atlanto-axial vertebral anatomy and three-dimensional CT measurement is becoming the key factor of success of posterior screw fixation surgery.ObjectiveThis study is focusing on the multi-observation and measurement of atlanto-axial vertebral from anatomy,3d CT imaging, trying to discuss the position, the direction, the angle and the depth when nailing into Atlanto-axial vertebral arch and lateral mass within security so that to provide reliable basis for clinical surgery.MethodsSpecimen of 100 cases (dry bone specimens of 80 cases, wet bone specimens of 20 cases) from atlas and axis specimens of normal adult, regardless of gender, age, and race. Using vernier calipers measurement (precision 0.02 mm) in length, photoshop 7.0 in angle to provide relevant anatomy parameters.Collecting 100 patients,whose (Agreed to inform patients) illness is caused by cervical bone hyperplasia, inflammation or trauma, but does not involve Atlanto-axial cervical vertebral injury, who have experienced the three dimensional CT scans from January 2013-June 2015. Adopting 3d restructuring software (SUN magic view 1000) to reconstruct three-dimensional CT, in order to obtain the relevant CT parameters measurement.Using SPSS13.0 to deal with the measurement data with the method of statistical processing, the results is showed in (x+S), with the test of paired t and single sample t respectively, and P<0.05 was statistically significant.Result1. the results of atlanto measurement:The atlas measurement of the left and right side (P>0.05, the difference has no statistical significance, and the result of the comparison among the measurements of CT, dry bone and wet bone showed P>0.05, the difference has no statistical significance. We used the average value taking from both sides. Numerical display measuring height of vertebral artery groove inside a third less than 1/3 of the lateral, but 58.3% of the lateral 1/3 height is greater than 4.0 mm; 3.5 mm<lateral 1/3 height 4.0 mm or less accounted for 13.3%; 1.7 mm<lateral 1/3 height 3.5 mm or less accounted for 28.3%; The lateral 1/3 height less than 1.7 mm (1.7%), minimum value is 1.60 mm, the maximum of 6.58 mm. The points of the nail in the after the height of the arch is greater than 4.0 mm accounted for 85.0%; After 3.5 mm<bow height 4.0 mm or less accounted for 8.3%,3.5 mm or less accounted for 5.0%, the minimum value is 2.36 mm, the maximum of 10.02 mm. Into the nail to lateral frontal middle distance of 27.55±2.01 mm (select important basis for the length of the screw, the minimum 24.58 mm,32.36 mm maximum, a atlas screw internal Angle of 15.29±2.15°, dip Angle on the beta of 3.78±1.07°.2. the results of axis measurement:posterior atlanto-axial pedicle height 7.59±0.98 mm, the width of 7.57±1.77 mm, the width of the area of common axis pedicle in which the screw is going is 100.0% greater than 4.0 mm,11.08 mm maximum, minimum 5.30 mm. Into the nail to lateral frontal middle distance of 26.47±1.85 mm,30.78 mm maximum, minimum 23.00 mm. Nail points into the vertebral arch height 11.98±1.16 mm, width 5.58±0.90 mm,13.34 mm maximum, minimum 4.52 mm. Transverse process of the outside of the hole to the vertebral canal from 6.72±1.22 mm. Axis Angle was 19.20±2.77°, the Angle of 28.03±3.60°Conclusion1. the measurement shows that the atlas vertebral artery groove which is the most weakness is essential to the screw, so the screw channel should be along the lateral vertebral artery, and the important reason for selecting the diameter of the screw should be in the 1/3 height of vertebral artery sulcus lateral; Axis of pedicle, which is necessary for the screw, which is the most weakness, is one of the important reference when choosing the screw diameter for the axis.2. As can be seen from the measurement data, so 58.3%the screw with 4.0 mm diameter can be used.13.3% with a diameter of 3.5 mm screw; 28.3%,with a diameter of 3.0 mm screw; 1.7% should choose other ways of screws. Vertebral can choose a diameter of 4.0 mm screw.3. the distance between the points of the nail and the lateral frontal is im portant basis when choosing the length of the screw, so we can choose the scr ew in the length between 22mm and 28 mm.