2025 Poster Presentations
P286: PETROUS TEMPORAL BONE DEHISCENCES: OUR EXPERIENCE AND A CADAVERIC CASE ILLUSTRATION
Ludovica Pasquini, MD; Chandrima Biswas, MD; Joshua Vignolles-Joeng, BA; Robert Macialek, MD; Kyle Wu, MD; Oliver Adunka, MD; Daniel Prevedello, MD; The Ohio State University
BACKGROUND: The petrous portion of the temporal bone, situated within the middle cranial fossa, contains the middle and inner ear structures, making them susceptible in cases of dehiscence.
Petrous bone dehiscence (PBD) can present asymptomatically or with complex syndromes depending on location, tissue herniation, and dural integrity. Common occurrences include tegmen dehiscence (TD) and superior semicircular canal dehiscence (SSCD).
Surgical intervention is typically reserved to patients with severe symptoms, aiming at symptom relief using the middle fossa or transmastoid approach.
This study reports our experience reconstructing PBD over 7 years and provides an analysis of surgical anatomy based on a cadaveric case and insights into PBD repair.
METHODS: This retrospective cohort study analyzed patients who underwent surgical repair for PBD at the Department of Neurological Surgery, The Ohio State University, Wexner Medical Center, OH, USA between 2016 and 2023.
We evaluated demographic data, preoperative assessments, neuroradiological findings, prior treatments, intraoperative findings, postoperative symptoms resolution, and complications.
RESULTS: 36 PBD repairs were performed (8 for SSCD, 25 for TD, and 3 for both SSCD and TD). 4 patients underwent bilateral treatment. The most reported preoperative symptoms were CSF otorrhea (59.3%), aural fullness (43.7%), pulsatile tinnitus (43.7%), and disequilibrium (31.2%). Preoperative hearing loss was noted in 87.5% of cases and 4 patients have already been diagnosed with idiopathic intracranial hypertension (IIH).
We performed 33 middle fossa approaches, 1 transmastoid approach, and 2 combined approaches.
For patients with SSCD, the canal was plugged with temporalis fascia and bone wax. Additionally, we used to reinforce the middle fossa floor with a large piece of temporalis fascia and bone graft.
For patient with TD, defects were resurfaced using temporalis fascia, bone graft, and collagen matrix in layers. In the 24 cases of meningoencephalocele encountered, the encephalocele was removed, and the dural defect was repaired using both inlay and onlay collagen matrices.
Clinical improvement was observed in 28 patients (87.5%).
During follow-up, every patient underwent lumbar puncture, and 9 new cases of IIH were diagnosed accounting for 40.6% in our series.
CONCLUSIONS: Our study indicates that surgical repair of PBD through the middle fossa approach yields favorable outcomes, improving symptoms and reducing potential complications. Intracranial pressure needs be measured in all these patients due to the possible association with IIH as shown in our study.
Illustration of anatomical structures in the middle fossa floor from a cadaver specimen.
1. Tegmen mastoideum 2. tegmen tympani 3. arcuate eminence 4. lesser petrosal nerve groove 5. greater superior petrosal nerve groove 6. foramen spinosum 7. meatal plane
Intraoperative images of our multilayer technique. A) Small piece of temporalis fascia (white arrow), B) bone wax (white circle), C) large piece of temporalis fascia (white asterisk), D) split calvarial bone graft (black asterisk) and collagen matrix (black arrow).
Schematic illustration of the materials used for dehiscences repair during middle fossa approach