Variation in optic recess angle with optic chiasm position

Abstract

Background: The position of the optic chiasm relative to surrounding structures is critical in planning surgical interventions for suprasellar lesions. This study explored the relationship between the angle of the optic chiasm and lamina terminalis (OC-LT) and the position of the optic chiasm. Methods: The study comprised 140 individuals who underwent midsagittal and axial MRI-T2 scans. The position of the optic chiasm was classified into three categories: sellar, prefixed, and postfixed. The OC-LT angle was measured in the midsagittal section. Results: The angle between OC-LT varied from 30 to 66 degrees with a mean of 46.6 degrees. The sellar position of the optic chiasm was predominant (85.2%), with smaller angles (30-39 degrees) significantly associated with a sellar chiasm location. Most cases with postfixed optic chiasm fell within a 40-49 degree angle range. Conclusions: The OC-LT angle variability can be linked to the position of the optic chiasm. Predominantly, smaller angles correlated with a sellar position of the optic chiasm, while larger angles were associated with a postfixed optic chiasm. This information is crucial for surgical planning in the suprasellar region.

Keywords

• Optic Chiasm
• Lamina Terminalis
• Chiasmatic Recess
• MRI-T2 Scans
• Suprasellar Lesions