Morphometric analysis of the foramen ovale in the Mexican population using computed tomography scan
Authors: Tirado-Ornelas Héctor Alonso , Cazadero-Márquez Jesús Ricardo , Cruz-Argüelles Carlos Antonio , Kleemann-Jaramillo José Enrique , Meza-Bautista Miguel Ángel , Santos-Franco Jorge Arturo 
Published: May 2024

Background:
The assessment of cranial foramina is an important part of the objective diagnostic and therapeutic study relevant to pathologies involving structures of the skull base. The study of the foramen ovale not only holds significance for anatomical development but also bears profound surgical importance, such as in trigeminal neuralgia, and diagnostic importance in tumors and various types of epilepsy. It becomes relevant in fine-needle aspiration techniques in perineural tumor procedures, for electroencephalographic analysis in seizures, and therapeutic procedures such as percutaneous trigeminal rhizotomy for trigeminal neuralgia.

Methods:
A cross-sectional study at the Department of Neurosurgery, Specialties Hospital, La Raza National Medical Center, Mexico City, involved 70 patients aged >18 years who underwent a single skull computed tomography scan between July 2023 and March 2024. Patients with sufficient scan quality and optimal visualization of skull base foramina were included in the study. Measurements of tomographic images were taken using Inobitec’s DICOM file viewer. Data analysis in Microsoft Excel yielded mean, standard deviation, and 95% confidence interval (CI) for morphometric parameters of the foramen ovale.

Results:
Analysis of tomographies from 70 patients revealed a total of 140 foramen ovale, evenly split between 25 males (35.7%) and 45 females (64.3%). The measurements for the maximum anteroposterior diameter, transverse diameter, and surface area of all foramina were as follows: 6.61 ± 0.25 mm (95% CI), 3.97 ± 0.21 mm (95% CI), and 20.84 ± 1.58 mm2 (95% CI), respectively. Specific measurements for the right and left sides were obtained: for the right side, 6.59 ± 0.26 mm (95% CI) and 3.89 ± 0.21 mm (95% CI) for the maximum anteroposterior and transverse diameters, respectively, and 20.38 ± 1.62 mm2 (95% CI) for the surface area. For the left side, the measurements were 6.63 ± 0.24 mm (95% CI), 4.05 ± 0.21 mm (95% CI), and 21.31 ± 1.55 mm2 (95% CI) for the maximum anteroposterior diameter, transverse diameter, and surface area, respectively. The maximum and minimum dimensions for anteroposterior and transverse diameters were 10.67 mm, 4.41 mm, 7.09 mm and 2.36 mm, respectively, with a corresponding range for the surface area of 10.16 mm2–44.13 mm2. The average minimum distance between the foramen ovale and the foramen spinosum was 2.32 ± 0.24 mm (95% CI). In males, the average size of the foramen ovale was 23.66 ± 1.61, which was 22% larger than the average size in females (19.28 ± 1.45) (P = 0.0001).

Conclusion:
The foramen ovale is one of the main anatomical structures of the skull base, and besides that, it is complex and not directly accessible for clinical evaluation, useful information can be obtained through morphometric analysis. The present study provides specific anatomical data with morphological patterns to increase the understanding of the characteristics of the foramen ovale in the Mexican population. These are intended to be helpful in the pursuit of acknowledging the morphometrics and thus being able to plan neurosurgical procedures in the middle cranial fossa.