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 five groups, category 1: 0 to 3 years old;
2: 4 to 7 years old; 3: 8 to 11 years old; 4: 12 to 15 years old; and 5: 16 to 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 22°, average OH of 12.3 ± 1.46 mm, and average OA of 36°. 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°, average OH of 12.7 ± 1.12 mm, and average OA of 36°. 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°, average OH of 12.1 ± 1.03 mm, and average OA of 32°. The average age in
category 4 was 13.2 years old, with an average DS-TV of 25 ± 2.72 mm, average AoA
of 19.5°, average OH of 13.1 ± 1.67 mm, and average OA of 31.4°. 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 17°, average OH of 13.3 ± 1.58 mm, and average OA of 34.1°.
Conclusion: 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.
