Abstract

Endonasal sinus surgery (ESS) is a common surgical procedure that is used to relieve chronic, problematic conditions associated with the paranasal sinuses of the cranium. One possible complication that can arise during ESS is damage to the bone surrounding the sinus. Complications due to this damage can include blindness, penetration into the eye orbit, periorbital injury, and dural lesions. In order to limit these complications, the least-dense portion of the bony sinus wall should be avoided. Previous research on plastinated specimens has shown that x-rays can be used to determine the areas of the sinus wall to avoid during ESS. A more accurate means of determining areas of bone to avoid during ESS is to use computerized tomography (CT), which images the body based on tissue density. Here, we present the results of an examination of 36 cranial CT scans provided by Saint Mary's, representing all age groups and both sexes. Using analytical software (Amira 3.5), the density of bone surrounding the maxillary and frontal sinuses were examined and the least-dense portion of the sinus walls were determined using Hounsfield Units (HU's). By determining the density of bone by an absolute measure (HU's), the area of bone to avoid during ESS can be delineated with accuracy.