Ideal Insertion Point and Angle of Cervical Pedicular Screws in Korean

ABSTRACT

STUDY DESIGN: A retrospective study. OBJECTIVES: Using computed tomography, it is to measure pedicle size of lower cervical spine in Koreas to find ideal insertion point and angle in fixating pedicular screws. SUMMARY OF LITERATURE REVIEW Although techniques in pedicular screw fixation and pedicle's anatomical shape in foreign populations have been well documented and studied, no anatomical study on lower cervical pedicle in Korean population has been reported. MATERIALS AND METHODS: A total of 180 patients with computed tomography taken at our institution were selected for the study. Width, total length, and length of pedicle, insertion point and angle, and safe insertion angles were measured on axial view. On sagittal view, height of pedicle, insertion point and angle, and safe insertion angles were determined. RESULTS: Mean height of study subject was 164.2cm. Mean width of pedicle was 5.5mm, mean height 7.2mm, mean total length 31.2mm, and mean length 14.8mm. Mean insertion point from 3rd to 7th cervical spines was medially 3.3mm from lateral mass and downward 4.7mm from margin of upper facet. Mean insertion angles from 3rd to 7th cervical spines were 41.6degrees axially and 6.4degrees sagittally. Calculated safe insertion angles were 8degrees on medial and lateral sides and 14degrees on superior and inferior sides. CONCLUSIONS: Using computed tomography images, ideal insertion point and angle were measured for pedicular screw insertion, but, due to individual variation, preoperative measurement of insertion point and angle on computed tomography is necessary.