Defining and detecting missed ligamentous injuries of the occipitocervical complex.

Study Design: Retrospective radiographic and clinical review of patients in a comprehensive trauma database.

Objective: The primary aim of this study was to detect occipitocervical complex (OCC) injuries initially missed at a level 1 trauma center.

Summary Of Background Data: Recent case series demonstrate that OCC injuries are potentially survivable. Delay in diagnosis can lead to increased morbidity and mortality.

Methods: Normative maximum values that included 97.5% of the population were defined, with a sample of 251 consecutive normal computed tomographic (CT) scans for the Basion-Dens Interval (BDI), atlantooccipital interval, and lateral mass interval (LMI) of C1-C2. Subsequently, 844 cervical CT scans from consecutive polytrauma patients were reviewed for the evidence of OCC injury. Measurements greater than the normative maximum values were considered suspicious for injury. A BDI greater than 12 mm or a BDI greater than 10 mm with a confirmatory magnetic resonance imaging was considered a definite evidence of an OCC injury, as was an LMI 4 mm or greater with confirmatory magnetic resonance imaging. The electronic medical record was reviewed to determine whether an injury was detected on any final neuroradiology report or during follow-up. RESULTS.: Five patients had evidence of atlantooccipital dissociation (AOD), and two had atlantoaxial dissociation (AAD). Of these, three cases of AOD and two cases of AAD were missed on the final report by the neuroradiologist. The undiagnosed patients were subsequently diagnosed by orthopedic surgeons consulted for axial spine or other musculoskeletal trauma. No patients who were diagnosed with AAD or AOD in the electronic medical record were missed by using the criteria of BDI greater than 10 mm and LMI 4 mm or greater to define OCC injuries.

Conclusion: OCC injuries can be missed even with standardized multidetector CT with multiplanar reconstructions. High-quality normative data used to determine a reliable picture archiving and communication system-based measurement of the OCC anatomy can detect ligamentous injuries initially missed in polytrauma patients.