Role of Sagittal Reformatted Computed Tomographic Images in the Evaluation of Orbital Floor Fractures

Abstract

The sagittal plane computed tomographic (CT) scan has been proposed as the most important radiologic view in the diagnosis of orbital floor fractures. Before the advent of high-resolution CT, several articles were published in the radiology literature debating the need for direct sagittal views, which required cumbersome patient positioning. Today, the ability to easily create high-quality sagittal reformations requires reassessment of the importance of this view in the evaluation of orbital floor fractures. Computed tomographic studies of 24 orbital floor fractures for which coronal and sagittal images were available were included. Five independent reviewers evaluated all image sets and recorded maximum fracture width, depth, posterior shelf length (PSL), and presence of medial wall fracture and of trap door deformity. Direct fracture width measurements were obtained via coronal images, whereas depth and PSL were measured directly in the sagittal plane. Indirect measurements in a given plane were obtained by counting the number of slices in which the fracture was present and multiplying by the slice thickness. Cronbach alpha analysis was used to provide an intraclass correlation coefficient, where greater values signify less interreviewer variability. The Cronbach alpha values for width, depth, and PSL were 64%, 59%, and 85% in the coronal view and 76%, 55%, and 51% in the sagittal view, respectively. The alpha values for presence/absence of medial wall fracture and trap door deformity were greater in the coronal view at 73% and 55%, respectively. The intrareviewer variability was not significantly correlated with the degree of patient rotation or CT scan slice thickness. The interreviewer variability was significantly less among attending reviewer then resident reviewers. There was less interreviewer variability when the measured variables were assessed indirectly (width was best assessed in the sagittal plane, and depth and PSL were best assessed in the coronal view). These findings support the idea that additional views aid the surgeon's ability to further define fracture anatomy than might be possible with any single view, thereby improving preoperative planning and reconstructive strategies.