Lívia Gaspar Fernandes, Alexandre Fogaça Cristante, Raphael Martus Marcon, Tarcísio Eloy Pessoa de Barros Filho, Olavo Biraghi Letaif

Morphology measures of the odontoid process in children under 12 years old were carried out to demonstrate the viability of anterior internal fixation in this population once their active profile may not be compatible with successful conservative treatment. During a 6-month period, 36 tomographic examinations of the cervical spine region that provided visualization of the odontoid process were selected. Group 1 included children between 6 and 9 years of age, and group 2 contained children from 9 to 12 years of age. There were 23 (63.8%) male patients and 13 (36.2%) female patients. Patients diagnosed with a tumor, an infection, fracture non-union, or congenital malformation were excluded. Exams were ordered as part of a protocol applied to non-specific neck pain and pediatric trauma entries. The following parameters were analyzed: (1) screw attack angle, (2) height of the odontoid process, and (3) minimal transverse diameter of the odontoid process. In Groups 1 and 2, the average values of the screw attack angle were 55.9° ± 2.3° and 54.8° ± 4.5°, respectively; the average heights of the odontoid process were 26.58 ± 3.28 and 29.48 ± 3 mm, respectively, and the average minimal transverse diameter of the odontoid process were 6.57 ± 1.08 and 6.23 ± 0.88 mm, respectively. The minimal transverse diameter of the odontoid process was statistically higher in males than that in females, regardless of age (p = 0.007). In both groups, the minimal transverse diameter of the odontoid process allowed for the use of one 3.5-4.5 mm screw for anterior internal fixation. These slides can be retrieved under Electronic Supplementary Material.