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 This study is designed as retrospective analysis. Setting The study setting comprises of tertiary academic medical center. Participants In total, 506 patients aged 0 to 18 who had undergone maxillofacial and or head CTs between 2009 to 2016 were involved. 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 three age groups adjusting for sex. Analysis of covariance (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 were 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.

Keywords: anatomical differences; intercarotid distance; olfactory fossa depth; skull base surgery.

Fig. 1

Radiographic measurements. ( A ) Piriform aperture, ( B ) Nare to sella distance, ( C ) sphenoid sinus width, ( D ) conchal pneumatization, ( E ) presellar pneumatization, ( F ) sellar pneumatization, ( G ) anterior sellar wall thickness, ( H ) olfactory fossa depth, ( I ) left lateral lamella cribriform angle, ( J ) intercarotid distance cavernous sinus, ( K ) intercarotid distance superior clivus.

Fig. 2

Piriform aperture (mm) by age (years), The measurement was reported as adjusted means for each patient age group in years. Error bars represent 95% confidence intervals.

Fig. 3

Anterior sellar wall thickness (mm). The measurement was reported as adjusted means for each patient age group in years. Error bars represent 95% confidence intervals.

Fig. 4

Depth of olfactory fossa (mm). The measurement was reported as adjusted means for each patient age group in years. Error bars represent 95% confidence intervals.

Fig. 5

Right lateral lamella cribriform angle (degrees). The measurement was reported as adjusted means for each patient age group in years. Error bars represent 95% confidence intervals.

Fig. 6

Left lateral lamella cribriform angle (degrees). The measurement was reported as adjusted means for each patient age group in years. Error bars represent 95% confidence intervals.

Fig. 7

Nare to sella distance (mm). The measurement was reported as adjusted means for each patient age group in years. Error bars represent 95% confidence intervals.

Fig. 8

Sphenoid sinus width (mm). The measurement was reported as adjusted means for each patient age group in years. Error bars represent 95% confidence intervals.

Fig. 9

Intercarotid distance (degrees) The measurement was reported as adjusted means for each patient age group in years. Error bars represent 95% confidence intervals.