Transpedicular Screw Fixation For The Lower Cervical: Anatomical Measurement And Clinical Application Research

Objective To explore a safety and efficacy technique for transpedicular screw placement in cervical spine by anatomical measurement and clinical application.Methods(1)the three-dimensional quantitative anatomy of Lower Cervical pedicle was determined in 24 adult Cervical dry specimens using vernier caliber and conimeter, the parameter included the height, the width, the length, the axis angulation of the pedical, average value and standard difference of the parameter in each level of the pedicles were calculated. (2)42 patients with cervical instability underwent transpedical screw fixation with the method of placing screw individually. The aim cervical pedicle Measured by X-ray film and CT preoperatively. The cortex at the point of insertion was penetrated with a high-speed burr and the entrance hole was "explore to feel" by 3mm curette, inserting the screws under the C arm by "fell", After making sure the point of insertion finally. All patients were evaluated CT and radiographically for the location of the pedicle screw.Result (1)The average value of height, width, length and thickness among the pedicles of C_3-7were 4.21mm,7.64mm,3.64mm,5.88mm,32.20mm,15.75mm,8.12mm,0.65mm and 1.72mm respectively. The angle of the axis in the sagittal plane was 47.12°±3.02°of C₃, 43.47°±1.49°of C₄, 40.15° ±2.58°of C₅, 38.55°±2.45°of C₆, 35.16°±2.10°of C₇. The angle of the axis in the horizontal plane was8.50°±2.50°of C₃, 4.83°±1.65°of C₄, 1.25°±1.45°of C₅, -(4.50°±2.50°) of C₆, -(8.50°±2.50°)of C₇. (2)246 screws were inserted in lower cervical and every screws were assessed in postoperative CT image, There were 9 screws showed perforation of the pedicle wall refer to post-operation CT scan, The correct rate of inserting is 96.5%. There were no injury of the vertebra atery, spinal cord or nerve root.Conclusion Various entities diagraph data had no significant difference between domestic and foreign dates, individual anatomic appearance of lower cervical pedicle varied a lot. The individual point and direction of penetration, diameter and length of screw should be determined by X-ray film and CT preoperatively. The technique of lower cervical transpedicle screw are still relativity safety. The individualized technique for placing pedical screws is safe and effective, and can be applied and popularized clinically.