Đánh giá chỉ số giải phẫu C1, C2 trên cắt lớp vi tính phục vụ phẫu thuật chấn thương cột sống cổ cao

A computed tomographic study of C1, C2 morphology for atlantoaxial screw fixation techniques

SUMMARY

Purpose: This study is aimed to define the ethnic differences in the radiological measurements on C1 and C2 in Vietnamese population in order to determine the feasibility of implement C1-2 fixation techniques.

Study design: Retrospective study.

Methods: From October 2017 to April 2018, 120 thin-slide (1 to 3 mm) computed tomography scans of the cervical spine were reviewed. Various dimensions of C1 and C2 were analyzed on axial, sagittal reconstructed CT images. The differences between the right and left sides and between males and females were statistically analyzed using t-test, with a p-value of < 0.05 considered significant.

Results: Mean anteroposterior dimension and transverse width of C1 lateral mass were 19.7±2.1 mm and 12.2±1.7 mm, respectively. Mean angle of the screw directed to maximal medial, lateral, cranial and caudal were 36.6±2.80, 28.2±3.00, 49.6±4.10 and 26.4±5.50 respectively. Average isthmus height, internal height and pedicle width of C2 were 5.8±1.0 mm, 4.8±1.3 mm and 5.0±1.3 mm. No significant differences between the right and the left side of C1, C2 parameters and between sex variations. The prevalence of high-riding vertebral artery was 13.8% and narrow pedicle was 17.9%.

Conclusions: this study shows that the morphology of C1 and C2 is variable between Vietnamese and other populations. Due to several cases may not be relevant for C1-2 fixation techniques, preoperative anatomy evaluation based on CT data need to be performed for screw placement and trajectory planning.

Key word: atlanto-axial trauma, C1 lateral mass dimension, high-riding verebral artery, C2 narrow pedicle.