The Ommaya reservoir is an implanted neurosurgical device that provides direct, repeated access to the brain's ventricular system without the need for repeated lumbar punctures. It consists of a small, dome-shaped chamber placed beneath the scalp and connected by a thin catheter to one of the lateral ventricles. Clinicians access the reservoir percutaneously with a needle to inject medications, withdraw cerebrospinal fluid (CSF), or relieve localized fluid collections.

Design and placement

The device has two main components: a subcutaneous reservoir with a self-sealing septum and a flexible catheter that terminates in a ventricular location. Placement is performed in the operating room under sterile conditions. The surgeon makes a small scalp incision and a burr hole, advances the catheter into a lateral ventricle, and secures the reservoir beneath the scalp. Practical descriptions of the surgical steps are discussed in standard neurosurgical texts and resources on surgery.

Typical uses and examples

  • Intraventricular chemotherapy for leptomeningeal cancer or other central nervous system malignancies, enabling higher local drug concentrations with reduced systemic exposure.
  • Repeated CSF sampling for diagnostic tests, such as culture or cytology, without lumbar puncture.
  • Administration of intraventricular antibiotics for difficult ventricular infections.
  • Delivery of experimental therapies (for example, gene or cell therapies) directly into the ventricular compartment in clinical trials.

The catheter is positioned within the brain's ventricular cavities; for basic anatomy see resources on the cerebral ventricles. The superficial chamber lies beneath the scalp as a palpable dome; many clinical summaries show the reservoir itself under the scalp at this location.

Advantages, alternatives, and limitations

Advantages include reliable ventricular access, fewer traumatic punctures, and the ability to achieve higher local drug levels. Alternatives include repeated lumbar puncture for intrathecal therapy or temporary external ventricular drains for acute CSF diversion, each with different indications and trade-offs. The Ommaya reservoir is not suitable when ventricles are collapsed, when active scalp or systemic infection exists, or when catheter placement would be unsafe.

Complications and maintenance

Potential complications include infection, catheter blockage or dislodgement, hemorrhage around the catheter tract, and, rarely, local skin erosion over the device. Because infection is a significant concern, strict aseptic technique is used when accessing the septum; infected systems are often removed and managed with systemic and intraventricular antibiotics. Periodic imaging (CT or MRI) and clinical follow-up help detect misplacement or malfunction.

Historically, the reservoir was introduced by neurosurgeon Dr Ayub K. Ommaya in the mid-20th century as a practical solution to repeated ventricular access. Since then it has become a recognized tool in neuro-oncology, infectious disease management of the CNS, and selected experimental therapies. For procedural details and patient guidance consult specialist sources and institutional protocols.