Frontobasal fractures: Anatomical classification and clinical significance

Background: Frontobasal injury is a classic craniomaxillofacial fracture affecting the anterior cranial base. No data exist regarding the degree of frontobasal injury and associated midfacial fractures. The authors propose a classification of frontobasal and midface fractures involving the cranial base based on cadaveric experiments and comprehensive clinical experience. Methods: An institutional review board-approved retrospective review was conducted on patients with frontobasal fractures from 1995 to 2005. Fractures were categorized by pattern, location, midfacial involvement (impure), and complications compiled. One hundred five cadaveric heads underwent blunt impact to the frontal bone and upper midface. Calvarial vault, cranial base, and midface fracture patterns were categorized. Results: Three frontobasal fracture patterns were identified. Isolated linear cranial base fractures constitute type I. Vertical-linear fractures of the skull vault (frontal bone) occur in combination with base fractures, representing type II (vault and base). Comminution of the frontolateral skull vault and orbital roof in association with a linear base fracture constitute type III. Two hundred ninety patients were identified with 49 complications (cerebrospinal fistula, 24; and infectious 25). Type III (n = 159) had the highest complication rate (impure, 29 percent; pure, 17 percent), followed by type II (impure, 19 percent; pure, 5 percent). There is essentially no extension of midface fractures to the cranial vault. Conclusions: Frontobasal fractures have three unique and reproducible patterns based on vector, location, and force. This new classification scheme, paired with known patterns of midfacial injuries, assists in fully understanding frontofaciobasal injury and its complications. Overwhelmingly, impure type II and any type III fractures are associated with a high rate of complications and must be carefully managed.