Imaging features of maxillofacial fracture on serial imaging exams

YU Baohai; CAO Lei; HAN Shuman; SHI Liang; ZHANG Xiaofei; SHI Yunheng; GUO Zhe; WU Huizhao; WU Wenjuan

doi:10.19300/j.2017.L5419zt

Abstract：Objective By analyzing the evolution of maxillofacial fracture on serial imaging exams, to provide evi-dences for clinical assessment of the fracture degree and injury time. Method A retrospective CT imaging analysis of the patients with maxillofacial fracture who visited the Third Hospital of Hebei Medical University during January 2016-March 2017 was performed. In total, 500 patients (age, 40.24±18.71 year-old;male n=369, female n=131) were included in the study.The time and reason of injuries were all confirmed. CT images were divided into 6 groups according to the interval time after injury, ultra-early stage(within 3 days), early stage(4 to 7 days), early-middle stage (8 to 14 days), middle stage (15 to 21 days), late-middle stage(22 days to 2 months), and late stage(after 2 months). Chi-square test was used to assess the imaging changes of fractures in the different interval time after injury. Results Forty-two of 500 cases were frontal fracture caused by high-energy impact,and all of them associated with multiple injuries.The fracture lines were clear and sharp within 1 week. The fracture edges were absorbed and became blunt/hardening 2 to 3 weeks after injury. The fracture lines commonly presented more than 2 months after injury. The obvious soft tissue swelling around the fracture and paranasal sinus cavity effusion were revealed 1 to 2 weeks after injury, and gas collection was concomitant in cases with fracture involving the paranasal sinus wall within 3 days.Twelve cases (28.6%) combined with intracranial hemorrhage. Five cases ( 10%) showed subdural effusion . Subarachnoid hemorrhage was absorbed in a week , however , absorbing epidural hematoma took more than 3 weeks. The fracture signs at different stages were significantly different (P<0.05) with exceptions for the epidural hematoma, subdural hematoma, and subdural effusion. Total 40 cases of medial orbital wall fractures were assessed. The fracture line was sharp with adjacent ethmoid sinus effusion in the early stage, and, the ethmoid sinus effu-sion was absorbed during 2 to 3 weeks after injury, and fracture areas commonly showed smooth depression. The fracture signs at different stages were significantly different (P<0.05), with an exception for the sign of medial rectus muscle en-largement. Fifty cases of nasal fractures were analyzed. Sharp fracture lines and soft tissue swelling near fractures were main early manifestations. The soft swelling disappeared gradually after 1 week,the fracture margins became smooth more than 3 weeks after injury.The soft tissue swelling, fracture margins at different stages were significantly different (P<0.05). Nasal fracture lines commonly showed no ossification during long time after trauma. Conclusion Realizing the evolution of maxillofacial fractures on imaging exams is helpful for identifying the degree of fracture and the related injury time.