Morphometric analysis of cervical spine pedicles using computed tomography scans and its surgical implication in adult Rwandan population

Abstract

Background: Studies on morphometric dimensions of cervical spine pedicles showed that differences are significant between races and gender. Among Rwandan population, there were no available data. Our study was aiming to describe the anatomical morphology of the cervical spine pedicles and give guidance to safe pedicle screws fixation. Method: Retrospective cross-sectional study by using recorded Computed Tomography (CT) scans images of normal cervical spines. Images were selected from Radiology department electronic database of Rwanda Military Hospital. The total of 125 cervical CT-scans taken from January 2017 to June 2019 were analysed by RadiAnt DICOM software. Linear and angular measurements from the second to the seventh cervical spine were recorded and a total of 9000 measurements was analysed. Descriptive analysis, student t-test and p-values were done by using Microsoft Excel and SPSS. Results and discussion: Pedicle Widths (PW) and Pedicle Heights (PH) were bigger on C2 (PW=6.38mm, PH=8.1mm) and C7 (PW=6.67mm, PH=7.99mm). Calculated percentage of safe pedicle fixation with a screw of 4.5mm was 96% on C2 and 98.4% on C7. Smaller values for PW and PH were on C3 and C4 with less percentage of pedicle fixation of 68% on C3 and 67.2% on C4. Pedicle lengths (PL) and Pedicle Axis lengths (PAL) were gradually increasing from C2-C7. In angular measurements, Pedicle Sagittal Angles were decreasing from C2-C7 (43.43˚ on C2 and 38.61˚ on C7). The Pedicle sagittal angles are more variable between persons and C2 angle was directing cephalic for some and caudal for others. There was no generalizable gender or side dominance. Conclusion: Based on our findings, despite more variations in Rwandan population, safe pedicle fixation surgery can be done at the level of C2 and C7 and always the individual CTscan analysis is important prior to surgery for proper anatomical analysis.