The Role of the Ommaya Reservoir in Innovative Approaches to Treating Brain Tumors

Medically reviewed by Prof. Shimon Slavin, MD. Updated: March 2026

For brain tumor patients, innovative treatments offer new hope. The Ommaya reservoir, a device designed for the delivery of therapy into the tumor cavity, has become an important tool in the management of brain tumors.

First described by neurosurgeon Ayub Ommaya in 1963, it has evolved from an experimental device into a recognized standard of neuro-oncology. At Biotherapy International, the Ommaya reservoir is used within individually tailored treatment protocols for local therapy, which may help enhance the anti-tumor effect and reduce the risk of recurrence.

What is an Ommaya Reservoir?

An Ommaya reservoir is a small, dome-shaped device surgically implanted under the scalp. It’s connected to a catheter that leads directly into the brain’s ventricular system, enabling direct delivery of therapeutic agents. About the size of a coin, it is virtually invisible under the scalp and does not interfere with daily activities.

What is the Ommaya reservoir used for?

The brain’s blood-brain barrier (BBB) often prevents medications from effectively reaching the tumor.

According to Pardridge WM (Journal of Cerebral Blood Flow & Metabolism, 2012), more than 98% of drugs are unable to effectively cross the blood-brain barrier.

The Ommaya reservoir overcomes this barrier by enabling direct delivery of therapy into the tumor cavity. This approach is particularly important in aggressive forms, including glioblastoma and anaplastic astrocytoma, where the effectiveness of systemic treatment is often limited.

Implantation and Safety

The implantation of an Ommaya reservoir is a surgical procedure performed under general anesthesia. Here’s how it typically works:

1. Preparation: The patient is given general anesthesia to ensure there is no pain during the procedure.

2. Incision: A small incision is made in the scalp, and a hole is drilled into the skull.

3. Placement: The reservoir, a dome-shaped device with a membrane that can be punctured, is positioned under the scalp, and the catheter is carefully threaded through the hole into the brain’s ventricular system or even directly into the tumor site, depending on the clinical situation.

4. Securing: The reservoir is secured, and the incision is closed with sutures.

The entire procedure takes approximately 1–2 hours. Most patients spend one night in the hospital and are discharged the following day.

The procedure is considered safe, but as with any surgery, there are risks, including infection, bleeding, or damage to surrounding brain tissue. After the operation, patients are typically discharged the following day and can return to their normal lifestyle, but contact sports should be avoided for the first six weeks after surgery.

Once the reservoir is in place, medication can be administered in a matter of minutes. The physician punctures the membrane through the skin with a fine needle. This is an outpatient procedure requiring no hospitalization.

Modern Approaches to Local Immunotherapy

Oncolytic viruses are viruses that can infect and kill cancer cells while sparing normal cells. By injecting these viruses directly into the brain tumor via the Ommaya reservoir, it may be possible to turn the tumor into an in situ anti-cancer vaccine. Thus, the immune system cells can once again recognize tumor antigens, a function that is lost in the development and progression of cancer.

Another treatment modality that is being explored as part of advanced cellular immunotherapy approaches is the ATACK method. This involves using intentionally mismatched donor lymphocytes, including T cells, NK cells, and NKT cells, which are targeted preferentially against cancer cells. Deliberately incompatible donor lymphocytes trigger a rejection-like reaction, effectively destroying cancer cells that might resist other treatments.

FAQ

Is the implantation procedure painful?

No. The procedure is performed under general anesthesia, so the patient feels no pain during the operation. Mild discomfort after surgery typically resolves within a few days.

Is the device visible from the outside?

The reservoir sits beneath the skin — it may be felt upon touch but is virtually invisible.

Is MRI compatible with an Ommaya reservoir?

Yes. The reservoir is MRI-compatible, allowing standard tumor monitoring to continue without interruption.

How long does the reservoir remain in place?

The reservoir stays in place for the duration of treatment. After therapy is complete, it can be removed or left in place.

Conclusion

The Ommaya reservoir, in combination with advanced treatment methods, represents a promising approach to treating brain cancer. This technique offers new possibilities for treating patients with high-grade brain tumors where traditional treatment options are often limited in effectiveness. Biotherapy International is committed to advancing these innovative treatment methods to achieve the best outcomes for its patients.