Extent of the frontal sinuses in the aspect of neurosurgical craniotomy approaches.

Frontal sinuses within the frontal bone can be a potential obstacle in neurosurgical approach in this region. Their unintended opening during craniotomy is not beneficial due to the risk of brain infections by bacteria inhabiting the sinus mucosa.  Therefore, such opening should be avoided whenever the surgical procedure does not involve the sinus itself. The aim of the study was the morphometric analysis of the frontal sinuses based on computed tomography imaging. The width, height, projection surface area and location of the highest and most lateral points of the sinuses were determined. The vertical diameter of the sinuses was found to be greater in men compared with women. The most lateral point of the sinuses was located higher in men, and in men was located higher on the left side. The results obtained may indicate that the frontal sinuses tend to be larger in men and that air cells in men extend further in the upper - lateral direction on the left side of the frontal bone. This may cause an increased risk of unintentional opening of the left frontal sinus during frontal craniotomy or pterional craniotomy with frontal extension.