Anatomical Parameters and Growth of the Pediatric Skull Base: Endonasal Access Implications

Abstract

Objectives: Endoscopic endonasal anterior skull base surgery has expanding use in the pediatric population, but the anatomy of pediatric patients can lead to limitations. This study aims to characterize the important anatomical implications of the pediatric skull base using computed tomography (CT) scans. Design: Retrospective analysis Setting: Tertiary academic medical center Participants: 506 patients aged 0-18 who had undergone maxillofacial and or head CTs between 2009-2016. Methods: Measurements included piriform aperture width, nare to sella distance (NSD), sphenoid pneumatization, olfactory fossa depth, lateral lamella cribriform plate angles, and intercarotid distances (ICD) at the superior clivus and cavernous sinus. These patients were then subdivided into 3 age groups adjusting for sex. ANCOVA models were fit comparing between all age groups and by sex. Results: Piriform aperture width, NSD, sphenoid sinus pneumatization as measured using lateral aeration and anterior sellar wall thickness, olfactory fossa depth, and ICD at the cavernous sinus was significantly different among all age groups (P<0.0001). Our results show that mean piriform aperture width increased with each age group. The mean olfactory fossa depth also had consistent age dependent growth. In addition, ICD at the cavernous sinus showed age dependent changes. When comparing by sexes, females consistently showed smaller measurements. Conclusion: The process of skull base development is age and sex dependent. During preoperative evaluation of pediatric patients for skull base surgery piriform aperture width, sphenoid pneumatization in both the anterior posterior and lateral directions, and ICD at the cavernous sinus should be carefully reviewed.

Special Considerations in Pediatric Endoscopic Skull Base Surgery

“…Patients younger than this may require drilling to allow for adequate sellar access. This is not an absolute contraindication to surgery, but places the patient at greater risk of complications [82]. Pneumatization of the sphenoid sinus is typically complete by age 10 [5,83].…”

The development of a pediatric skull base team: how, where and why?

“…This is especially relevant when a two-surgeon, four-handed technique is required for resection with several instruments working simultaneously. Anatomic factors like the size of the piriform aperture, intercarotid distances, and extent of sphenoid sinus pneumatization can further restrict the endoscopic approach and are impacted by both age and sex [9,10 ▪ ]. The size and thickness of the cranial bones can also affect intraoperative positioning and the decision to place skull pins for operative stabilization [11].…”