An Introduction to the Orbital Buttresses.

Abstract

Summary: Facial buttresses are supportive bony structures of the facial skeleton that form a thick, strong, and protective framework for the face. Surgical fixation may be required to restore morphology and function when damage to these buttresses occurs. The authors sought to determine whether, similar to buttresses of the facial skeleton, buttresses of the internal orbit exist. They analyzed 10 human cadaver skulls imaged by microcomputed tomography. Image processing, and thickness and heat mapping, were performed using Avizo and ImageJ software. After identifying the orbital buttresses, the authors reviewed computed tomography scans of patients who had orbital fractures over a 3-year period to determine the frequency of fracture of the orbital buttresses. The authors identified 5 buttresses of the internal orbit: superomedial fronto-ethmoidal strut with the deep orbital buttress, inferomedial strut with the posterior ledge, inferior orbital fissure, sphenoid-frontal superolateral strut, and the sphenoid lip. The mean (SD) threshold orbital buttress thickness was 1.36 (0.25) mm. A total of 1186 orbits of 593 individuals were analyzed for orbital buttress involvement. Orbital buttresses were spared in 770 (65%) orbits. The inferomedial strut with the posterior ledge was the most commonly fractured buttress in 14.4% of orbits ( n = 171), followed by the sphenoid strut and lip (66 [5.6%]). To the authors' knowledge, this is the first description of the buttresses of the internal orbit. Orbital reconstruction for fracture repair or oncologic purposes requires the support of orbital buttresses. Understanding the anatomy of orbital buttresses is crucial for successful surgical planning, proper implant positioning, and restoration of function and appearance.