Temporal Bone Trauma: Typical CT and MRI Appearances and Important Points for Evaluation

To assess the practicality and utility of the traditional classification system for temporal bone fracture (transverse vs. longitudinal) in the modern Level I trauma setting and to determine whether a newer system of designation (otic capsule sparing vs. otic capsule violating fracture) is practical from a clinical and radiographic standpoint. The University of Massachusetts Medical Center Trauma Registry was reviewed for the years 1995 to 1997. Patients identified as sustaining closed head injury were reviewed for basilar skull fracture and temporal bone fracture. Clinical and radiographic records were evaluated by using the two classification schemes. A total of 2,977 patients were treated at the trauma center during this time. Ninety (3%) patients sustained a temporal bone fracture. The classic characterization of transverse versus longitudinal fracture (20% vs. 80%, respectively) was unable to be determined in this group; therefore, clinical correlation to complications using that paradigm was not possible. By using the otic capsule violating versus sparing designation, an important difference in clinical sequelae and intracranial complications became apparent. Compared with otic capsule sparing fractures, patients with otic capsule violating fractures were approximately two times more likely to develop facial paralysis, four times more likely to develop CSF leak, and seven times more likely to experience profound hearing loss, as well as more likely to sustain intracranial complications including epidural hematoma and subarachnoid hemorrhage. The use of a classification system for temporal bone fractures that emphasizes violation or lack of violation of the otic capsule seems to offer the advantage of radiographic utility and stratification of clinical severity, including severity of Glasgow Coma Scale scores and intracranial complications such as subarachnoid hemorrhage and epidural hematoma.

The beta(2)-transferrin assay is a specific method to identify cerebrospinal fluid (CSF). Hitherto, this test has not been widely used for the routine screening of patients with suspected CSF leakage. The purpose of this study was to investigate the clinical relevance of the identification of beta(2)-transferrin by comparing the test results with other diagnostic measures and intraoperative findings. Case series. Retrospective analysis of 182 patients tested once or multiple times for beta(2)-transferrin. Information was obtained regarding different diagnostic procedures applied to diagnose CSF leakage. The effectiveness of those diagnostic measures was compared. The main indication to test for beta(2)-transferrin was posttraumatic rhinorrhea (25%), followed by spontaneous (22%) and postsurgical (22%) rhinorrhea. In 35 of 205 cases, beta(2)-transferrin was detected in the tested specimens. Thirteen of these required surgical intervention for treatment of the CSF fistula, and the leakage site was identified in all of them. Taking all results into consideration, the highest correlation was observed between the beta(2)-transferrin assay, intrathecal fluorescein application, and surgical exploration. The beta(2)-transferrin assay is a reliable method for confirming suspected CSF and should be used as a primary screening method in all patients with suspected CSF leakage. Although less invasive, the beta(2)-transferrin assay almost matches the high sensitivity achieved by exploratory surgery and intrathecal application of fluorescein. However, the possibility of bias should be carefully considered, and in particular, negative results should be critically compared with clinical symptoms and with results from other diagnostic procedures.

The objectives were to evaluate the clinical relevance of traditional temporal bone radiographic descriptors and to investigate the efficacy of an alternative fracture classification scheme. Retrospective consecutive case series. Charts and computed tomography scans representing 155 temporal bone fractures at a level I trauma center were reviewed. Fracture types were correlated with clinical presentation and outcomes. The traditional classification system (i.e., longitudinal, transverse, or mixed) correlated poorly with clinical findings such as facial nerve weakness and cerebrospinal fluid leakage. It also had limited utility in predicting conductive hearing loss and sensorineural hearing. An alternative schema distinguishing petrous from nonpetrous involvement demonstrated better correlation with these measures. Cerebrospinal fluid leak was 1.1 times more common in transverse than in longitudinal fractures but was 9.8 times more common in petrous than in nonpetrous fractures. Similarly, facial nerve injury more strongly correlated with fractures through the petrous temporal bone than did the other fracture types. Sensorineural hearing loss did not correlate with the transverse fracture classification but was significantly more prevalent in petrous fractures. Likewise, conductive hearing loss did not correlate with longitudinal fractures but was four times more common in the "middle ear" subcategory of nonpetrous fractures. Traditional temporal bone fracture descriptions correlate poorly with clinical findings. However, simply distinguishing petrous from nonpetrous involvement demonstrates significant correlation with the occurrence of serious sequelae of temporal bone fractures. Subcategories of mastoid and middle ear involvement further refine this classification schema to correlate with minor complications. This simple, radiographically based scheme better focuses clinical resources and attention toward more likely sequelae.