3D CT stereoscopic imaging: an improved anatomical understanding of the anterior ethmoid sinus and frontal sinus drainage pathway

S.J Zinreich,F.A Kuhn,M Solaiyappan,D Kennedy,N.R London Jr,W Hosemann

doi:10.4193/rhin20.061

Abstract

OBJECTIVE: The objective of this presentation is to display a series of new anatomical concepts and terms regarding the frontal si- nus, its drainage pathway and cells vs. spaces of the anterior ethmoid, based on Three-Dimensional Computer X-ray Tomography Stereoscopic Imaging (3DCTSI) and contrast these concepts to those reported in the current literature. METHODS: Given the new anatomic observations provided by 3DCTSI, and the widespread anatomic variations a small sample was initially selected to describe our observations. Six exemplary cases according to the “Classification of Fronto-Ethmoidal cells” by Kuhn, Bent et al., Lee et al., expanded by Wormald et al., and adopted by Ramakrishnan et al., Huang et al., and Void et al. (1-7) were chosen to illustrate our detailed anatomic observations. Additional observations and data of prevalence identified in a larger series will follow. RESULTS and CONCLUSION: Conceptually, the anterior ethmoid “cells” are in essence “spaces” with openings that communicate with the middle meatus and/or the ethmoidal infundibulum. The frontal sinus and frontal recess are a united and continuous three-dimensional, irregularly shaped space, the Frontal Sinus/Recess Space (FSRS). The uncinate process has two segments: the Ethmoidal Uncinate Process (EUP), which encompasses the Infundibular Space of the EUP (IS-EUP), currently known as the Agger Nasi cell; and the Turbinal Uncinate Process (TUP), which borders the Turbinal Infundibulum (TI) medially. The superior attach- ment of the EUP will be detailed in each of the six cases (Table 2). The middle meatus and infundibular passages are the drainage pathways from the frontal sinus and maxillary sinus to the nasal cavity.

Highlights

The introduction of Endoscopic Sinus Surgery (ESS) was aided by the improved imaging of X-ray polytomography, which was replaced by planar X-ray Computed Tomography (CT) in 1985 . [8,9] In the late 1980s, the introduction of CT Multiplanar Reconstruction, advanced Functional Endoscopic Surgery and Image-Guided Surgery improved our understanding of the detailed sinus anatomy (Figure 1) . [8-13] Observations of the anatomical subunits, introduced in the late 1800s, [14-22] and the movement towards less invasive, “precision surgery”, and highlight the importance of continuing to improve our anatomic knowledge of the Frontal Sinus Drainage Pathway, as well as, most recently the posterior ethmoid and sphenoid sinus anatomy . [23-55]
Note the uncinate process (U), fusing with the middle turbinate at the axilla, and its superior-lateral extension to fuse with the lamina papyracea, creating the roof of the IS-Ethmoidal Uncinate Process segment (EUP)
As the potential for minimally invasive surgery grows, increased recognition of the sinus anatomy and its common variations becomes increasingly important, and 3D CT Stereoscopic Imaging displays (3DCTSI) provides the opportunity to clearly the anatomy and variations which previously, were not appreciated.We present our observations of the normal 3D anatomy as displayed with 3DCTSI of the anterior ethmoid and fronto-ethmoidal transition zone in six exemplary cases, representative of the “Classification of the Fronto-ethmoidal cells” by Kuhn and expanded by Wormald et al, and adopted by Huang et al.; Ramakrishnan et al; and Void et al [1-7]

Summary

Introduction

The introduction of Endoscopic Sinus Surgery (ESS) was aided by the improved imaging of X-ray polytomography, which was replaced by planar X-ray Computed Tomography (CT) in 1985 . [8,9] In the late 1980s, the introduction of CT Multiplanar Reconstruction, advanced Functional Endoscopic Surgery and Image-Guided Surgery improved our understanding of the detailed sinus anatomy (Figure 1) . [8-13] Observations of the anatomical subunits, introduced in the late 1800s , [14-22] and the movement towards less invasive, “precision surgery”, and highlight the importance of continuing to improve our anatomic knowledge of the Frontal Sinus Drainage Pathway, as well as, most recently the posterior ethmoid and sphenoid sinus anatomy . CT Imaging of sinuses post 2018 CT MPR 2018 Axial Coronal F S R S Sagitta l Sagittal. Coronal a CT MPR images of sinuses late 1980s The introduction of Endoscopic Sinus Surgery (ESS) was aided by the improved imaging of X-ray polytomography, which was replaced by planar X-ray Computed Tomography (CT) in 1985 . [8,9] In the late 1980s, the introduction of CT Multiplanar Reconstruction, advanced Functional Endoscopic Surgery and Image-Guided Surgery improved our understanding of the detailed sinus anatomy (Figure 1) . [8-13] Observations of the anatomical subunits, introduced in the late 1800s , [14-22] and the movement towards less invasive, “precision surgery”, and highlight the importance of continuing to improve our anatomic knowledge of the Frontal Sinus Drainage Pathway, as well as, most recently the posterior ethmoid and sphenoid sinus anatomy . [23-55]

Methods

Results

Discussion

Conclusion