Computed tomographic measurement of cervical pedicles for transpedicular fixation in a Malay population

MI Yusof, LK Ming, MS Abdullah
Department of Orthopaedics, School of Medical Science, USM, Kelantan, Malaysia

PURPOSE. To measure the cervical pedicles and assess the feasibility of transpedicular fixation in a Malay population.

METHODS. 960 computed tomography (CT) scans of bilateral C2 to C7 pedicles of 80 Malays were compared. 22 men and 24 women aged <60 (mean, 37.3; range, 18-56) years were defined as young patients, whereas 18 men and 16 women aged 60 or over (mean, 63.9; range, 60-76) years as elderly patients. An inner diameter of <3.0 mm (85% of a 3.5-mm screw) was defined as 'unfeasible' and a medial or lateral wall thickness of <1.0 mm as 'unsafe' for cervical pedicle screw fixation.

RESULTS. In the respective young versus elderly groups, the inner diameters ranged from 1.94 to 2.80 mm versus 2.51 to 3.37 mm in men, and from 1.52 to 2.31 mm versus 1.64 to 2.46 mm in women. Medial wall thickness ranged from 1.25 to 1.46 mm versus 1.13 to 1.48 mm in men, and from 1.28 to 1.72 mm versus 1.10 to 1.24 mm in women. Lateral wall thickness ranged from 0.80 to 0.90 mm versus 0.66 to 0.88 mm in men, and from 0.85 to 0.99 mm versus 0.59 to 0.86 mm in women.

CONCLUSION. The cervical spine of Malays may not be adequate to accommodate a 3.5-mm pedicle screw for transpedicular fixation, as this procedure may risk adjacent vital structures.