Differentiation between Posterior Sinuses Using the Medial Orbital Floor as a Landmark.

Objectives This study aims to evaluate the difference in height between the floors of the posterior ethmoid and sphenoid sinuses with respect to the medial orbital floor (MOF) to confirm this difference as a landmark for identification of the posterior sinuses. It also aims to describe this difference regarding the type of pneumatization of the sphenoid sinus (conchal, presellar, and sellar). Design A cross-sectional study was conducted. Study Center The study was conducted at the Department of Radiology of Hospital de Clínicas de Porto Alegre, a tertiary care university hospital in Southern Brazil. Materials and Methods A standardized and computerized analysis of 100 tomography scans of sinuses (200 sides), in patients older than 18 years, was carried out. Results Mean vertical distance (height) from the MOF to the floor of the posterior ethmoid and sphenoid sinuses was 0.72 ± 1.85 mm and 9.48 ± 3.81 mm, respectively. There was no statistically significant difference as compared with sex and side. We found conchal-type sphenoid sinus pneumatization in 1.5% (n = 3), presellar in 13.5% (n = 27), and sellar in 85% (n = 170), whereas the vertical distance between the MOF and the floor of the sphenoid sinus was 2.04 ± 0.81 in the conchal-type sinuses, 5.71 ± 2.49 in the presellar sinuses, and 10.21 ± 3.52 in the sellar sinuses. No sphenoid sinus showed its floor above the MOF, regardless of the type of pneumatization. Discussion and Conclusion The present study demonstrates that there is a difference between the floor of the posterior sphenoid and ethmoid sinuses in adults, which is more evident when the sphenoid sinus is well pneumatized. These data suggest that the difference in height between the floors of the sinus investigated in our study may be considered during endoscopic sinus surgery to guide adequate localization, but the surgeon should be aware of the type of pneumatization of the sphenoid sinus to use this landmark.

Computed tomography imaging study of the superior attachment of the uncinate process.

BACKGROUND: The superior attachment of the uncinate process (SAUP) is an important landmark in the nasofrontal recess, but its anatomical distribution is still unclear. The objective of this study was to assess the location and number of superior attachments of the uncinate process on computed tomography (CT) images. METHODOLOGY: A cross-sectional, retrospective study conducted at the Department of Radiology, Hospital de Clinicas de Porto Alegre, Brazil. Sinus CT scans of adult patients with no history of sinonasal surgery, craniofacial fractures, malignant neoplasms, or malformations were examined for identification of the site of SAUP. RESULTS: 152 CT scans (304 sides) were assessed. The SAUP was appropriately identified in 292 sides (96%). Six distinct SAUP patterns were identified: to the lamina papyracea or anterior ethmoidal cells (193, 63.48%); to the middle turbinate (19, 6.25%); to the skull base (19, 6.25%); to the lamina papyracea and middle turbinate (29, 9.53%); to the lamina papyracea and skull base (29, 9.53%); and to the skull base and middle turbinate (3, 0.98%). CONCLUSION: The site of superior attachment of the uncinate process is highly variable, but is in contact with the lateral nasal wall in 82.5% of the cases.