Characteristics of Dehiscence of Lamina Papyracea Found on Computed Tomography Before Orbital and Endoscopic Endonasal Surgeries.

The aim of this study was to identify characteristics of dehiscence of the lamina papyracea found on computed tomography (CT) before orbital and endonasal endoscopic surgeries.The authors retrospectively reviewed the medical records of all patients who underwent orbital tumor removal, orbital decompression, and dacryocystorhinostomy from January 2012 to December 2015. The diagnosis of dehiscence of the lamina papyracea was made based on a bone defect with protrusion of orbital fat into the ethmoid sinus on CT, with no history of orbital trauma and/or eye movement disturbance on the same side.Overall, 6 patients (1.4%) were identified from among 315 patients (90 orbital tumors, 150 orbital decompressions, and 75 endoscopic endonasal dacryocystorhinostomies). All patients were asymptomatic. All dehiscence was limited to the anterior ethmoid sinus, with fat prolapse of <1 cm. An opacified ethmoid sinus was found in 1 of the 6 patients (17%) with dehiscence of the lamina papyracea. Operative area included the dehiscence site in 1 patient. Intraoperatively, the periorbita was found to be defected at the dehiscence site with intact connective tissue septa. The dehiscence site served as a landmark for the operation.Dehiscence of the lamina papyracea is a rare anomaly, but occasionally encountered in orbital and endoscopic endonasal surgeries.