Medical Therapy Alone for Ommaya Reservoir-Associated Bacterial Meningitis: When It Works and When It Fails

Background and objectives: Administration of intraventricular chemotherapy through Ommaya reservoir is indicated for certain forms of leptomeningeal disease. However, ventricular reservoirs carry a substantial risk of infection. The conventional approach to managing reservoir-associated infections involves removal of the reservoir and systemic antibiotic therapy, but this strategy necessitates additional procedures to remove and subsequently replace the device. We evaluated the success rate of standardized, multimodal medical therapy alone in treating reservoir-associated meningitis and factors associated with the need for device removal.

Methods: We used the International Neoplastic Meningitis Academic Registry Consortium database to identify patients at our institution with reservoir-associated bacterial meningitis. A standardized antibiotic regimen of oral rifampin, intraventricular vancomycin, and another intravenous antibiotic based on the infecting organism was used to treat infections for 10 to 14 days. We evaluated the rate of infection clearance and factors associated with success of therapy without reservoir removal.

Results: Forty-eight infections in 33 patients (5.79% of all patients) were identified. Before infection, reservoirs were accessed a median of 6 (1-14) times. Infections were eradicated without reservoir removal in 39 of 48 patients (81.3%). Cerebrospinal fluid (CSF) leak/local wound infection was the only factor associated with the need for reservoir removal (odds ratio = 18.3 [3.68-141], P < .001) on multivariate analysis, and 98.0% of patients without this characteristic were cured with medical therapy alone. Other characteristics such as age, myelosuppression, tumor histology, number of reservoir accesses, concurrent systemic chemotherapy, or infecting organism were not predictive of reservoir removal. Random forest and gradient boost machine learning models further confirmed CSF leak/local wound infection to be the most important predictor of removal.

Conclusion: Most patients who develop a reservoir-associated infection can be successfully treated with a standardized antibiotic regimen alone, without additional surgery for reservoir removal and subsequent replacement. However, CSF leak/reservoir site infection is strongly associated with failure of medical therapy and warrants early device removal.