Introduction: There is a lack of reports describing the incidence of frontal sinus extension lateral to the supraorbital foramen. For surgeons utilizing the orbitozygomatic approach, this relationship is important to prevent the occurrence of frontal sinus violation.
Methods: Prior to dissection, ten human cadavers had computed tomography scans obtained with 1mm slices. The frontal sinus and bilateral supraorbital forama were identified radiographically. The supraorbital foramen or notch was then dissected bilaterally on each cadaver. Using frameless stereotaxy, the accuracy of radiographic location was confirmed. Multiple measurements were taken regarding the location and relationship between the supraorbital foramen and frontal sinus.
Results: On average, the supraorbital foramen is located 2.4cm lateral to the nasal midline. Only 4.7mm of bone separated the center of the supraorbital foramen and the lateral wall of the frontal sinus. The frontal sinus extended laterally past the location of the supraorbital foramen in eight of ten specimens. The average distance from the lateral edge of the supraorbital foramen to the furthest lateral edge of the frontal sinus was 4.9mm. There was no significant difference in the location of the supraorbital foramen (or notch) when measured on CT compared to in vivo dissection.
Conclusions: To minimize the risk of frontal sinus violation, surgeons utilizing the orbitozygomatic approach should assure that their trajectory is not perpendicular to the supraorbital foramen. When a perpendicular trajectory was used, the frontal sinus would be entered in 80% of the examined specimens. By using a trajectory of 35 degrees with respect to the supraorbital foramen, the frontal sinus would only be violated in 2 of the 20 examined surgical approaches.
Patient Care: How will your research improve patient care:
Armed with this knowledge, surgeons will have a better knowledge of the proper angle to use with the craniotome to avoid sinus violation when considering the addition of an orbitotomy to a craniotomy.
Learning Objectives: By the conclusion of this session, participants should be able to describe the anatomical relationship between the frontal sinus and the supraorbital foramen as well as a method to avoid frontal sinus violation when performing an orbitotomy.