Authors: Martin Piazza, MD
Temporal bone fractures (TBF) occur in up to 10% of head injuries. This fracture may result in hearing loss, facial nerve palsy, and CSF leak. High resolution CT of the temporal bone (CTTB) is often reflexively ordered to characterize TBFs, exposing patients to high doses of radiation.Methods: We performed a retrospective chart review of patients < 18yo who presented to our institution with skull fractures between 2007-2017. For all patients we collected demographics, mechanism of injury, fracture location, injury severity score, clinical neurologic exam, and cranial radiation exposure data. Location, initial/follow-up audiograms, facial nerve function, and skull base repair procedures were collected in the TBF cohort.
From 2007-2017 there were 412 skull fracture patients, including 106 (25%) TBFs. Among the TBF patients, 50 (47%) involved the squamous and 56 (53%) involved the petrous temporal bone. 9 (8%) violated otic capsule. 21 (20%) had hearing loss at time of injury, with 12 (11%) experiencing persistent hearing loss on follow-up. 7 (6.6%) patients had a facial nerve injury, with 6 recovering with steroids and 1 requiring a surgical intervention. All TBFs received CTTB. 34 (32%) underwent a CTTB with mean 52mGy of cranial radiation exposure alone in 48 hours following injury. 72 (68%) received a reformatted CTTB from another head CT with radiation exposure rates similar to those without TBF (~28mGy).
Reflexively or auto-ordered studies that may not contribute clinically meaningful information should be minimized, particularly when there is the potential harm such as ionizing radiation. Our data reveals that even with a relatively high rate of hearing loss and facial nerve injury, < 1% of TBF cases require intervention, and that CTTB did not change clinical mangement. This suggests that a reflexive CTTB order has more narrow clinical utility in TBF, especially when it is not possible to reformat a prior cranial CT.