What is an Ommaya reservoir?

An Ommaya reservoir is a plastic device that’s implanted under your scalp. It’s used to deliver medication to your cerebrospinal fluid (CSF), a clear fluid in your brain and spinal cord. It also allows your doctor to take samples of your CSF without doing a spinal tap.

Ommaya reservoirs are usually used to administer chemotherapy medication. Your brain and spinal cord have a group of blood vessels that form a protective screen called the blood-brain barrier. Chemotherapy that’s delivered through your blood stream can’t cross this barrier to reach cancer cells. An Ommaya reservoir allows the medication to bypass the blood-brain barrier.

The Ommaya reservoir itself is made up of two parts. The first part is a small container that’s shaped like a dome and is placed under your scalp. This container is connected to a catheter that’s placed in an open space within your brain called a ventricle. CSF circulates within this space and provides your brain with nutrients and a cushion.

To take a sample or administer medication, your doctor will insert a needle through the skin of your scalp to reach the reservoir.

An Ommaya reservoir is implanted by a neurosurgeon while you’re under general anesthesia.


Getting an Ommaya reservoir implanted does require some preparation, such as:

  • not drinking alcohol once the procedure is scheduled
  • not taking vitamin E supplements within 10 days of the procedure
  • not taking aspirin or medications containing aspirin during the week before the procedure
  • telling your doctor about any additional medications or herbal supplements you take
  • following your doctor’s guidelines about eating and drinking before the procedure


To implant the Ommaya reservoir, your surgeon will start by shaving your head around the implant site. Next, they’ll make a small cut in your scalp to insert the reservoir. The catheter is threaded through a small hole in your skull and directed into a ventricle in your brain. To wrap up, they’ll close the incision with staples or stitches.

The surgery itself should only take about 30 minutes, but the entire process can take about an hour.


Once the Ommaya reservoir is placed, you’ll feel a small bump on your head where the reservoir is.

You’ll likely need a CT scan or an MRI scan within a day of your surgery to make sure it’s correctly placed. If it needs to be adjusted, you may need a second procedure.

While you recover, keep the area around the incision dry and clean until your staples or stitches are removed. Be sure to tell your doctor about any signs of infection, such as:

  • a fever
  • headaches
  • redness or tenderness near the incision site
  • oozing near the incision site
  • vomiting
  • neck stiffness
  • fatigue

Once you’ve healed from the procedure, you can return to all of your normal activities. Ommaya reservoirs don’t require any care or maintenance.

Ommaya reservoirs are generally safe. However, the procedure to place them carries the same risks as any other surgery involving your brain, including:

  • infection
  • bleeding into your brain
  • partial loss of brain function

To prevent infection, your doctor might prescribe you antibiotics following the procedure. Talk to your doctor about any concerns you have about complications. They can go over their approach with you and let you know about any additional steps they’ll take to lower your risk of having complications.

Ommaya reservoirs usually aren’t removed unless they cause problems, such as an infection. Though at some point in the future you may no longer need your Ommaya reservoir, the process to remove it carries the same risks as the process to implant it. Generally, removing it isn’t worth the risk.

If you have an Ommaya reservoir and are considering having it removed, make sure you go over the potential risks with your doctor.

Ommaya reservoirs allow your doctor to easily take samples of your CSF. They’re also used to administer medication to your CSF. Due to the risks associated with removal, Ommaya reservoirs usually aren’t taken out unless they’re causing a medical problem.