Anatomical margins of uncinectomy in endoscopic sinus surgery.

Background: Endoscopic sinus surgery is a common and generally safe ENT procedure. Orbital injury is a rare but devastating complication. The distance between the uncinate process and the lamina papyracea is the safety margin to avoid entering the orbital cavity and has not been measured previously.

Methods: The authors reviewed 330 consecutive coronal CT scans of the paranasal sinuses to measure this distance and identify variation.

Results: The distance can be as narrow as 0.1 mm and varies between sides. An air cell lateral to the uncinate is not uncommon; it increases the distance considerably p < 0.001 but is frequently unilateral (22%). Gender does not have an effect on this distance p = 0.90.

Conclusion: It is essential to carefully examine the area on a CT scan especially when performing front-to-back uncinectomy during endoscopic sinus surgery. The variation between the right and left sides should be considered to avoid unsafe assumptions.