Lumboperitoneal Shunt Combined With Ommaya Reservoir Enables Continued Intraventricular Chemotherapy for Leptomeningeal Metastasis With Increased Intracranial Pressure

BACKGROUND: Intra-cerebrospinal fluid (CSF) chemotherapy for leptomeningeal metastasis (LM) can be delivered intraventricularly via an Ommaya reservoir. However, hydrocephalus associated with LM can interfere with chemotherapeutic drug distribution, and ventriculoperitoneal shunts can prevent drug distribution to the extra-ventricular CSF space. This study examined the feasibility of combining a lumboperitoneal (LP) shunt with an Ommaya reservoir to both control intracranial pressure and allow for intraventricular chemotherapy. METHODS: We identified 16 patients with LM who received both an Ommaya reservoir and an LP shunt, either concurrently or sequentially, and subsequently received intraventricular chemotherapy. The feasibility of this combination for intraventricular chemotherapy was evaluated by assessing 1) the distribution of intraventricularly injected drugs in CSF samples collected 0, 6, and 12 h post-injection and 2) adverse events associated with the procedure and drug administration. RESULTS: Patients received a median of seven rounds (range 1–37) of intraventricular chemotherapy during a median follow-up period of 5.2 months after LP shunt insertion. Pharmacokinetic data were obtained from six patients. Baseline methotrexate (MTX) levels from Ommaya reservoirs varied from 339.9 µM to 1,523.5 µM. CSF sampled from LP shunt reservoirs revealed an elimination half-life (t(1/2)) of 2.63 h, and the mean ratio of MTX concentration at 12 h to that at baseline was 0.05±0.05, ensuring drug distribution from the ventricle to the spinal canal. Nine patients (56%) underwent revision surgery due to catheter migration, malfunction, or infection. Among these patients, CSF infections attributable to intraventricular chemotherapy (n=3) occurred, but no infections occurred in later cases after we began to employ a complete aseptic technique. CONCLUSION: LP shunt combined with Ommaya reservoir insertion is a feasible option for achieving both intracranial pressure control and the continuation of intraventricular chemotherapy in patients with LM.