RT Journal Article
SR Electronic
T1 Computerized Tomography–Based Morphometric Analysis of Odontoid in 100 Egyptian Patients
JF International Journal of Spine Surgery
JO Int J Spine Surg
FD International Society for the Advancement of Spine Surgery
SP 59
OP 65
DO 10.14444/7008
VO 14
IS 1
A1 PATIL, NIRMAL D.
A1 ESSAM, MOHAMMAD
A1 RAGAB, RAAFAT KAMAL
A1 ELSAGHIR, HESHAM
YR 2020
UL https://www.ijssurgery.com/content/14/1/59.abstract
AB Background There is still no consensus in the literature regarding the use of 1 screw or 2 screws. A number of studies have proved ethnic variations in the morphometry of the odontoid. There is no literature on the morphometry of odontoid in Egyptian patients.Methods Computerized tomography (CT) scans of the head and cervical spine of 100 healthy (no evidence of cervical spine fracture) patients of Egyptian origin were studied. Measurements were performed using Horos software, which allowed exact morphometric measurements to be taken at a specific angle in the axial, coronal, and sagittal planes.Results The mean age was 48.57 ± 15.39 years (range, 18–79 years; 56 male and 44 female patients). The mean radiologically calculated screw length and the mean radiologically calculated screw insertion angle were 38.21 ± 2.2 mm and 55.7° ± 3.84°, respectively. The mean anteroposterior and transverse diameter of the odontoid at the waist in the axial cut were 11.02 ± 1.05 mm and 8.92 ± 0.93 mm, respectively. A total of 54% and 6% of the study sample had the transverse waist diameter of the odontoid in the axial cut below 9 mm and 7.4 mm, respectively. A total of 48% of the male and 61% of the female patients had their transverse diameter of the odontoid at the waist below 9 mm. There was a statistically significant difference in all the measurements of the odontoid between the male and female patients except in the anteroposterior diameter of the base of odontoid (P = .06) in the axial cut, and the radiologically calculated screw insertion angle (P = .57). The mean distance between the apex of the odontoid and the screw exit was 1.8 ± 0.75 mm (range, 0–3 mm).Conclusions CT-based morphometric analysis of the odontoid is necessary before using 2-screw fixation technique. Single 4.5-mm Herbert screws could be used in all Egyptian patients without the need for CT-based morphometric analysis of the odontoid. The posterior screw can violate the posterior wall of the odontoid, with a reduced fracture hold and a chance of injuring the thecal sac.