Otogenic cranial base osteomyelitis: a proposed prognosis-based system for disease classification.

Objectives: To review the presentation, microbiology, and long-term results of treating otogenic cranial base osteomyelitis to develop a prognosis-based disease classification system.

Patients And Methods: Thirty-eight patients with otogenic cranial base osteomyelitis treated between 1989 and 2002 were studied. Patient demographics, presentation, pathogens, details of therapy, and disease-specific survival were recorded. Patients were stratified using Technetium-99 single-photon emission computerized tomography (SPECT) at presentation into 4 grades: I, mild uptake; II, focal mastoid/temporal bone uptake not reaching midline; III, petrous temporal bone uptake reaching midline; and IV, uptake crossing midline, involving the contralateral temporal bone. Actuarial analysis was used to identify prognostic factors.

Results: There were 27 men. The average age at presentation was 65 +/- 16 years (range, 19-95 yr). The median age-adjusted Charlson comorbidity score was 5, and 63% of patients were diabetic. The most common presenting symptoms were pain and otorrhea, and 8 patients had cranial nerve neuropathy. Pseudomonas aeruginosa was the most common bacterial pathogen (n = 28; 74%), and 9 patients had fungal or mixed infections. On average, antibiotics were administered for 161 days, and 6 patients had concomitant surgery. The average follow-up was 33 months, and 3-year disease-specific survival was 76%. Univariate predictors of survival were the SPECT grade, fungal/mixed infections, Charlson score, immune compromise, and cranial nerve neuropathy. The only independent predictor of survival on multivariate Cox regression was the SPECT stage at presentation.

Conclusion: Cranial base osteomyelitis is associated with significant morbidity and mortality and requires prolonged treatment. Long-term outcome can be predicted from the initial SPECT scan.