Measurement of Subaxial Cervical Vertebral Height using Computed Tomography for Optimisation of Anterior Cervical Plate in North Indian Population

Abstract

Introduction: The morphometric analysis of subaxial cervical spine is of importance to improve the surgical outcome of the patients who undergo Anterior Cervical Discectomy and Fusion (ACDF) with anterior cervical plating. The morphometric values of cervical spine vary for from population to population and so does the size of the anterior cervical plate. Aim: To analyse the average height of subaxial cervical spine and its implication in anterior cervical plating. Materials and Methods: The present cross-sectional study included 70 patients who underwent Computed Tomography (CT) scan for evaluation of cervical spine between May 2021 to October 2021 in Safdarjung hospital, New Delhi. The height of subaxial cervical spine (from C3 to C7 vertebrae) was measured from superior most to inferior most bony part on the anterior surface of the corresponding cervical vertebrae in midsagittal section (A) and superior most to inferior most of the central cervical vertebral body in midsagittal section (B) using Radiant viewer version 4.2.1 software. The Indian and imported anterior cervical plate, screw hole diameter and screw hole to plate edge were measured both on ventral and dorsal aspect with vernier caliper. The data was tabulated and mean, standard deviation and other variations were calculated. Results: The smallest vertebra was C5, A (11.62±1.15 mm) and B (9.95±1.35 mm). C7 was the largest with measurements of A (14.07±1.35 mm) and B (12.46±1.29 mm). The total distance of cervical plate over the anterior cervical vertebral body measures 7.9 mm and 7.6 mm for imported and Indian implant, respectively. Considering the least cervical vertebral height of 9.95±1.35 mm, the gap remaining from the adjacent disc after mounting Imported and Indian implant was 2.05±1.35 mm and 2.35±1.35 mm, respectively. Conclusion: C7 was the largest vertebrae and C5 was the smallest. Thus, the Indian and imported anterior cervical plate leaves a gap of less than 5 mm from adjacent disc to plate at C3,C4,C5 and C6.