Radiographic Findings vs. Intraoperative Findings in Middle Cranial Fossa Encephalocele Repair

Introduction: Encephalocele of the temporal bone is a pathology with a wide range of sequalae with varying morbidity including chronic otitis media and mastoiditis, hearing loss, cerebrospinal fluid leak, and meningitis. As such, ability to diagnose tegmen defects, early encephalocele, and true encephalocele is of paramount importance. Computed Tomography (CT) scans are the current gold standard for diagnosis of bony abnormalities of the temporal bone. Due to the nature of CT scans and the thickness of the skull base itself, true diagnosis of encephalocele and skull base dehiscence are incredibly difficult. To improve the diagnostic value of CT scan in temporal bone encephalocele, we sought to compare CT findings in temporal bone scans, with intraoperative findings during middle cranial fossa encephalocele repair. We hypothesize that CT scans are generally under calling encephaloceles. Methods: We designed a retrospective cohort study to evaluate the differences of encephalocele diagnosis between CT scan and intraoperative findings. All middle cranial fossa encephalocele repairs performed on adults by a single surgeon at one tertiary care facility from 2016 to 2025 were included in the study. All patients included in the study were taken to the OR for encephalocele as diagnosed by our primary surgeon based on his read of the CT scan. All patients underwent CT Internal auditory canal/posterior cranial fossa at one of the two institutions. Presence of encephalocele diagnosed by the reading radiologist from the scan vs. presence or absence of encephalocele intraoperatively were the primary outcomes. Results: In all, 116 procedures were performed. 14 (13.7%) were diagnosed with an encephalocele on CT by the reading radiologist. 81 (70.4%) were found to have skull base defects intraoperatively. CSF leaks were noted in 18 (15.7%) patients, granulation tissue or dural inflammation was noted in 11 (9.6%) patients. There was no statistical significance between the right and left ear, or male and female gender. Conclusion: Overall, the number of scans which called encephalocele on CT scan was significantly fewer than was observed intraoperatively. This supports that radiologist reads of temporal bone CT scans may be under calling temporal bone encephaloceles, in fact our data shows that the sensitivity of CT for diagnosing encephalocele is only 17.3%. This is clinically relevant because with our current diagnostic means we may be missing these skull base defects, which may be leading to progression of encephalocele or other unwanted sequelae. Further research needs to be conducted in evaluating the overall risk of untreated encephaloceles. Otologic and neurosurgeons alike should be away of this diagnosis and possibly have a lower threshold to take patients to the OR for encephalocele repair. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany