2025 Proffered Presentations
S277: AGE-RELATED VARIATION IN ANTERIOR SKULL BASE PARAMETERS INFLUENCING ACCESS TO THE HYPOTHALAMIC AND THIRD VENTRICULAR REGION IN PEDIATRIC PATIENTS
Michael T Bounajem, MD1; Diwas Gautam, BS1; Sam Tenhoeve, BS1; Allison Liang, MD1; Michael Levy, MD2; Douglas Brockmeyer, MD1; William T Couldwell, MD, PhD1; Robert C Rennert, MD1; 1University of Utah; 2University of California San Diego
Introduction: Transcranial with or without transorbital approaches are important techniques for complex tumor resections in both adult and pediatric patients. Consideration of working angles is particularly important for surgeons accessing the hypothalamic and third ventricular region, especially with anterolateral approaches due to limitations in brain retraction. This is of relevance when treating children due to significant variations in the size of anterior skull base structures, and therefore variable working angles, throughout development.
Methods: A retrospective analysis was conducted to identify pediatric patients with high resolution imaging at a single center. Both computed tomography and magnetic resonance images were included. Patients were divided into 5 groups, category 1: 0-3 years old; 2: 4-7 years old; 3: 8-11 years old; 4: 12-15 years old; and 5: 16-18 years old. Patients with pathologies that could result in deformation of the skull base/third ventricle and hypothalamus were excluded from analysis. Measurements consisted of distance from the dorsum sellae to the roof of the third ventricle (DS-TV), the angle of approach to the roof of the third ventricle from the level of the nasion (AoA; the angle between a horizontal line at the nasion and a line from the nasion to the roof of the third ventricle), orbital height (OH; the distance from a line at the level of the fronto-ethmoidal suture to a line connecting the superior most portion of each orbit), and finally the oblique angle (OA; angle on the sagittal plane between a horizontal line projecting to the planum sphenoidale and a line parallel to the orbital roof).
Results: A total of 50 patients were included, with 10 patients in each age category. The average age in category 1 was 1.49 years old, with an average DS-TV of 21.5±3.72 mm, average AoA of 22º, average OH of 12.3±1.46 mm, and average OA of 36º. The average age in category 2 was 5.4 years old, with an average DS-TV of 24.4±3.32 mm, average AoA of 22 º, average OH of 12.7±1.12 mm, and average OA of 36 º. The average age in category 3 was 9.4 years old, with an average DS-TV of 25.7±3.13 mm, average AoA of 20.5 º, average OH of 12.1±1.03 mm, and average OA of 32º. The average age in category 4 was 13.2 years old, with an average DS-TV of 25 ±2.72 mm, average AoA of 19.5º, average OH of 13.1±1.67 mm, and average OA of 31.4º. The average age in category 5 was 16.5 years old, with an average DS-TV of 24.9 ±2.78 mm, average AoA of 17º, average OH of 13.3±1.58 mm, and average OA of 34.1º.
Conclusions: With increasing age, patients demonstrated increasing OH and DS-TV, but decreasing AoA. OA did not obviously correlate with patient age. These counter-balancing developmental changes likely have a net-neutral effect on the surgical accessibility of the hypothalamic/third ventricular region in pediatric patients via anterolateral approaches.