Evaluation of Concomitant Orbital Floor Fractures in Patients with Head Trauma Using Conventional Head CT Scan: A Retrospective Study at a Level II Trauma Center

Abstract

Background: Patients with head trauma may have concomitant orbital floor fractures (OFFs). The objective of our study was to determine the specific CT findings and investigate the diagnostic performance of head CT in detecting OFFs.

Methods: We analyzed 3534 head trauma patients undergoing simultaneous head and facial CT over a 3-year period. The clinical data and specific head CT findings between patients with and without OFFs were compared.

Results: In our cohort, 198 patients (5.6%) had OFFs visible on CT. On head CT, orbital floor discontinuity, gas bubbles entrapped between floor fragments, inferior extraconal emphysema, and maxillary hemosinus (MHS) were more commonly observed among patients with OFFs (p < 0.001). The absence of MHS had a high negative predictive value (99.7%) for excluding OFFs. Among the different types of MHS, the pattern showing high-attenuation opacity mixed with mottled gas had the highest positive predictive value (69.5%) for OFFs and was the only independent predictor of OFFs after adjusting for the other CT variables in all patients with MHS.

Conclusion: Head CT may serve as a first-line screening tool to detect OFFs in head trauma patients. Hence, unnecessary facial CT and additional radiation exposure may be reduced.

Keywords: clear sinus sign; emergency departments; head CT; head trauma; maxillary hemosinus; orbital floor fracture; radiation exposure.

Figure 1

CT images of a 29-year-old male with assault-related head trauma and a concomitant left orbital floor fracture (OFF). An axial head CT image (A) and the corresponding coronal facial CT image (B) show gas bubbles (black arrow) entrapped between the discontinuous floor fragments (white arrows). Left type 2 maxillary hemosinus (MHS) (arrowhead) and a left zygomatic fracture are also noted in (A).

Figure 2

CT images of a 62-year-old female with motorcycle crash-related head trauma and a concomitant left OFF. An axial head CT image (A) and the corresponding coronal facial CT image (B) show inferior extraconal emphysema (straight white arrow) beneath the inferior rectus muscle (black arrow), orbital fat herniation into the maxillary sinus (arrowhead), and the depressed fragments of fractured orbital floor (open curved arrow).

Figure 3

CT images showing three patterns of MHS related to OFFs associated with head trauma. (A) Type 1: high-attenuation opacity mixed with mottled gas in the left maxillary sinus (arrow) in a 52-year-old male with motorcycle crash-related head trauma. (B) Type 2: air–fluid level in the left maxillary sinus (arrow) in a 26-year-old female with motor vehicle collision-related head trauma. (C) Type 3: full opacification of the left maxillary sinus (arrow) in a 79-year-old male with fall accident-related head trauma.

Figure 4

Diagnostic performance of the total and the three subtypes of MHS.