Extent of optico-carotid recess is significantly associated with presence of bony dehiscences and bone thickness in the optico-carotid area

Background: The objectives of this study were to evaluate the frequency of bony dehiscences in the optico-carotid recess (OCR) area and to measure the thickness of the bony lamellas bordering the OCR, according to our previously proposed OCR classification taking into account the extent of the recess. Methodology: A total of 100 human cadaver heads (n= 200 sphenoid sinuses) were investigated. Samples were divided into groups according to the presence and extent of OCR (no OCR, sub-optical OCR, latero-optical OCR). Bony dehiscences were visually identified and bone thickness was measured by using a high-resolution micrometer. Results: A bony dehiscence in the OCR area was observed in 20%. A significant difference in bony dehiscence occurrence rate between OCR types was found. The wall thickness of the bony carotid artery- and optic nerve canals bordering the OCR were 0.25 ± 0.16 mm and 0.27 ± 0.15 mm, respectively. Significant differences between OCR groups in bony wall thickness of the carotid artery canal and optic nerve canal were found. Samples with a latero-optical OCR had a significant thinner wall of the carotid artery and optic nerve canal than samples with a sub-optical OCR and no OCR. Conclusions: The current results indicate that the presence of an extended OCR, e.g. latero-optical, is highly associated with a greater risk of bony dehiscences and thinner bony lamellas in the OCR region.