3D CT stereoscopic imaging: observations of the frontal and anterior ethmoid sinuses development from birth to early adulthood

Objective: Our objective is to provide observations demonstrated with 3Dimensional Computed x-ray Stereoscopic Imaging (3DCTSI) in the evaluation of the anterior ethmoid and frontal sinus development from birth to age 18. Methods: This is a retrospective evaluation of patient’s CT studies performed over a fifteen-year period, reported as normal studies, and included 53 patients (142 sides) from birth to age 18. Results: At birth, there are two spaces covered by folds, the uncinate and bulla lamellae. The spaces communicate with the Middle Meatus (MM) through the emerging ethmoid infundibulum (EI) and the retrobulbar recess space (RBRS). In the first month after birth, an expansile and breakdown developmental phase blend and continue throughout the growth into the teenage years. The 3D images reveal dark lamellar structures, on the surface of the medial lamina papyracea as well as bridging the broken spatial outlines. The dark lamellae represent the mucosal lamina propria, in unossified lamellae and are the origin of permanent spatial walls. From ages 4 to 18 years, initially, the frontal recess (FR) and later the MM penetrate into the cancellous frontal bone creating the frontal Sinus (FS), the frontal septum (FS), Inter-Frontal Sinus Septal Cell (IFSSC), as well as the Fronto-Ethmoidal and Frontal Bulla Spaces. Conclusion: 3DCTSI is the first intuitive imaging modality to reveal the microanatomical development of the anterior ethmoid and frontal sinus anatomy.

N, Hosemann W. Supplements and refinements to current classifications and nomenclature of the fronto-ethmoidal transition region by systematic analysis with 3D CT microanatomy

Objective: The microanatomy of the fronto-ethmoidal transition region has been addressed in several classifications. CT stereoscopic imaging (3DCTSI) provides improved display and delineates three defined complex “spaces”, the Frontal Sinus/Frontal Recess Space, the Infundibular Space of the Ethmoid Uncinate Process, and the Ethmoid Bulla Space (FSRS, IS-EUP, EB), none of which were adequately described with the “cell” terminology. We present details on the 3D microanatomy, variability, and prevalence of these spaces. Methods: 3D stereoscopic imaging displays (3DCTSI) were created from 200 datasets. The images were analyzed and categorized by a radiologist (SJZ), and consultant otolaryngologists, focusing on 3D microanatomy of the fronto-ethmoidal transition, the frontal recess/frontal sinus, and drainage pathways, in comparison to established anatomical classification systems. Results: The anterior ethmoid is subdivided into seven groups with the following core properties and prevalence: 1. The horizontal roof of the IS-EUP is attached to the superior half of the frontal process of the maxilla (19%); 2. The IS-EUP extends into the frontal recess (6.5%); 3. The IS-EUP extends into the frontal recess and the frontal sinus (18.5%); 4. A bulla is seen in the medial frontal sinus (3%); 5. The ethmoid bulla and supra bullar space extend into the frontal sinus (7%); 6. Lamellae extend into the FSRS antero-superiorly (25%); 7. FSRS expansion expands below the upper half of the frontal process of the maxilla (FSRS) (21%). Conclusion: 3-D analysis of the detailed anatomy provides important new anatomic information with the increased focus on precision surgery in the region.