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Neurosurgery Medical Definitions


Tumor within the substance of the brain or spinal cord made up of astrocytes – cells which support the nerve cells (neurons) of the brain and spinal cord – often classified from Grade I (slow-growing) to Grade III (rapid-growing).


A procedure performed to view blood vessels after injecting them with a special dye that outlines them on x-ray.


Pertaining to the blood vessels and, especially, the arteries that supply the brain.


Ependymomas are a rare type of glioma that develop from the cells that line the ventricles (fluid-filled spaces in the brain) and the central canal of the spinal cord. They can be found in any part of the brain or spine, but are most commonly found in the main part of the brain, the cerebrum. Ependymomas may spread from the brain to the spinal cord in the cerebrospinal fluid.

Glial cells

A type of cell that surrounds nerve cells and holds them in place. Glial cells also insulate nerve cells from each other.

Image-guided Surgery

The use of a real-time correlation of the operative field to a preoperative imaging data set that reflects the precise location of a selected surgical instrument to the surrounding anatomic structures.

Interventional radiology

Interventional neuroradiologists use specialized intra-arterial and venous catheters to treat vascular abnormalities of the brain. Through a variety of techniques, they can treat aneurysms and vascular malformations percutaneously (through the skin) that might otherwise require surgery.


A fluid-filled cavity in the heart or brain.

ISO-C3D C-arm

A specialized tool that enables the surgeon to know at every moment during surgery where he or she is working in the patient’s body accurately — particularly when difficult to see with the naked eye.


The three membranes that cover and protect the brain and spinal cord.


A brain tumor caused by cancer elsewhere in the body spreading to the brain.


A tumor. An abnormal growth of tissue. The word neoplasm is not synonymous with cancer. A neoplasm may be benign or malignant.

Nerve Sheath Tumors

A nerve sheath tumor is a type of tumor of the nervous system (nervous system neoplasm) that is made up primarily of the myelin surrounding nerves.


A tumor of peripheral nerves due to abnormal proliferation of Schwann cells.


Neuropathologists are subspecialists of pathology that have several additional years of training and additional Board Certification by the American Board of Pathology. They specialize in analysis of diseases of the brain, spinal cord, muscle and nerves. Over the past several years, new research and technologies in Neuropathology have produced significant advances in the pathologic analysis of brain and spinal cord disease. This has resulted in the better recognition of less common tumors and brain abnormalities, previously mistaken for malignant tumors.


A radiologist who specializes in the use of x-rays and scanning devices for the diagnosis and treatment of diseases of the nervous system. A neuroradiologist may be concerned with the clinical imaging, therapy, and basic science of the central and peripheral nervous system, including but not limited to the brain, spine, head and neck.


Oligodendroglioma is a type of glioma and develops from cells called oligodendrocytes that produce the fatty covering of nerve cells. This type of tumor is normally found in the cerebrum, particularly in the frontal or temporal lobes.

Pineal region

A type of brain tumor that occurs in or around the pineal gland, a tiny organ near the center of the brain.


The main endocrine gland, producing hormones that control other glands and many body functions, especially growth.


Hormone controlling lactation (production of milk)


A neoplasm originating from Schwann cells (of the myelin sheath) of neurons. Schwannomas include neurofibromas and neurilemomas.

Spinal Instability

The inability of the spinal column, under physiologic loading, to maintain its normal configuration. Spinal instability can result from congenital defects, trauma, degenerative change, or neoplastic diseases affecting the vertebrae, intervertebral discs, or spinal ligaments. It may lead to damage to the spinal cord or nerve roots or to painful spinal deformity.

Stealth Surgical Navigation System

A method in neurosurgery for locating points within the brain using an external, three-dimensional frame of reference usually based on the Cartesian coordinate system.

Stereotactic Radiosurgery

A form of radiation therapy that focuses high-powered x-rays on a small area of the body. Other types of radiation therapy are more likely to affect nearby healthy tissue. Stereotactic radiosurgery better targets the abnormal area.


Blood supply.