Is the Supraorbital Notch a Reliable Landmark to Avoid the Frontal Sinus?

BACKGROUND: When performing a craniotomy involving the orbital bar, the supraorbital notch is a potential landmark to localize the lateral extent of the frontal sinus. Avoidance of the frontal sinus is important to reduce the risk of postoperative surgical site infection, epidural abscess formation, and mucocele development.

OBJECTIVE: To determine the reliability of the supraorbital notch as a marker of the lateral location of the frontal sinus.

METHODS: Cadaveric dissections were used with image guidance software to define the relationship between the frontal sinus and supraorbital foramen.

RESULTS: The supraorbital notch was located 2.54 cm from midline and the lateral extent of the frontal sinus extended 2.84 mm lateral to the supraorbital notch. When performing a craniotomy extending medially to the supraorbital notch at a perpendicular angle, the frontal sinus was breached in 65% of craniotomies. When the craniotomy ended 10 mm lateral to the supraorbital notch, the rate of frontal sinus breach decreased to 10%.

CONCLUSION: When performing a craniotomy involving the supraorbital notch, a lateral to medial trajectory that ends 15 mm to the supraorbital notch will minimize the risk of frontal sinus violation.