Introduction: Skull base osteomyelitis (SBO) secondary to otitis externa is a rare but highly morbid
disease, and early diagnosis and treatment is important for improving outcomes. We
investigated current practices in diagnostic imaging for SBO and treatment outcomes,
along with other patient characteristics that may affect outcomes.
Methods: This retrospective cohort study identified all patients at our institution diagnosed
with SBO from 01/01/2007 to 12/31/2022. The following data were collected for each
patient: imaging modality and results, specialty requesting the imaging, diabetes
and immunocompromise status, facial nerve involvement, and culture results. Outcome
was defined as treatment duration > 8 weeks required. Fisher’s exact test was used
for analysis.
Results: We identified 35 patients with SBO. Initial diagnosis was made with CT in 13/35 cases,
MRI in 2/35 cases, CT and MRI in 9/35 cases, and a combination of CT, MRI, and/or
nuclear medicine in 10/35 cases. PET was used in 2/35 cases. In 31 patients with data
on treatment duration, 4/4 (100%) patients with aspergillus-positive SBO required
treatment >8 weeks compared to 8/27 (29.6%) patients without aspergillus (p = 0.0157). No significant associations with treatment duration were found for imaging
modality, diabetes/immunocompromise status, or facial nerve involvement.
Conclusion: Despite recent literature recommending a shift towards PET/CT or PET/MRI to diagnose
SBO, this has not carried over to current practice patterns at our institution, likely
due to lack of awareness and cost. Imaging modality was not associated with treatment
duration. Patients with aspergillus-positive SBO tend to require longer treatment.
