2025 Proffered Presentations
S044: SPONTANEOUS INTRAPARENCHYMAL OTOGENIC PNEUMOCEPHALUS DUE TO TEGMEN DEFECT REPAIRED WITH DERMAL ALLOGRAFT, CALCIUM PHOSPHATE, AND AUTOLOGOUS BONE FLAP
Sarah Lawhon, MD, MPH; Moises Arriaga, MD; Cole Lewis, MD; Louisiana State University - New Orleans
Introduction: Spontaneous otogenic pneumocephalus (SOP) is a rare entity, accounting for less than 1% of all pneumocephalus cases.1 There have been fewer than 45 cases of SOP reported since 1954.2, 3, 4 Here we present a case of SOP due to tegmen defect with repair using a novel 3-layer approach utilizing dermal allograft (Alloderm™)5, calcium phosphate (HydroSet™)6, and autologous bone.
Case Description: A 42-year-old female with no relevant past medical history presented due to 5 days of severe headache, lethargy, and cognitive dysfunction including forgetfulness and word finding difficulty. She denied recent trauma, previous cranial or otologic surgery, otologic infections, fever, vertigo, otorrhea, hearing loss, and air travel. The only possible inciting factor elicited was frequent sneezing. On exam, the patient was somnolent (GCS 14) but had no focal neurologic deficits. Initial imaging showed a large intraparenchymal focus of air within the left temporal lobe superior to the petrous temporal bone, causing mass effect and minimal midline shift (Figure 1). Tegmen tympani and mastoideum defects were identified (Figure 2), and an encephalocele was visible on MRI.
Figure 1. Initial CTH
Figure 2. Initial CT temporal
The patient was admitted to the ICU and started on oxygen via nonrebreather, empiric antibiotics, and levatiracetam. On hospital day 2, she was taken to the OR for middle fossa craniotomy with tegmen defect repair. Upon removal of the bone flap, the dura was noted to be tense. As the dura was elevated posteriorly to anteriorly off the middle fossa floor, there was a sudden relaxation as air was evacuated. Multiple bony defects were noted in the middle fossa floor medial to the petrous ridge. The dura in this area was very thin to absent with associated encephalocele. Intra-operative ultrasound was used to evaluate for residual pneumocephalus. A three-layer repair was used to reinforce the middle fossa floor. HydroSet™ coated AlloDerm™ was placed over the bony defects, followed by the craniectomy flap, and then AlloDerm™ above that, directly below the dura. The mastoid air cells were waxed and another piece of AlloDerm™ was laid down for an extra barrier. A titanium mesh plate was placed over the craniotomy defect and the incision was closed. Post-operative scans showed some residual but decreased pneumocephalus (Figures 3 and 4). The patient had significant improvement in headaches and alertness. At 1 month follow-up, her symptoms had resolved, and imaging showed complete resolution of pneumocephalus.
Figure 3. Post-op CTH
Figure 4. Post-op CT temporal
Discussion: On literature review, repair of middle fossa defects for SOP used temporalis facia, temporalis muscle, fascia lata, periosteum, synthetic dural substitute, autologous bone, and fibrin sealant.2,3,4,7-16 There were no reported cases that used dermal allograft for repair. This 3-layer approach using AlloDerm™ above and below a bone flap is our preferred technique with 590 consecutive cases. Coating the AlloDerm™ with HydroSet™ powder facilitates visualization of the repair. While AlloDerm™ is frequently used for anterior fossa repairs, there are few reports of its use in middle cranial fossa defects.17,18