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L

L# – The letter L followed by a number identifies a specific vertebra in the lumbar spine. For example, L3 is the 3rd vertebra in the lumbar spine.

LAMINA – The flattened or arched part of the vertebral arch, forming the roof of the spinal canal.

LAMINECTOMY – A surgical procedure that removes the lamina (roof) or shingle-like portions of a vertebrae in order to create more space for the nerves, which relieves pressure on the spinal cord and nerve roots.  Decompressive laminectomy, in which the lamina of the vertebrae is removed, is a common surgery for the lumbar spine (the five vertebrae of the lower spine between the ribs and the pelvis).  A neurosurgeon may perform a laminectomy with or without fusing vertebrae or removing part of a disc.

LAMINOTOMY – An operation to form a hole in or remove part of the lamina, which is done to allow more room for the spinal cord and nerves.

LAPARASCOPIC SPINAL FUSION – A minimally invasive procedure involving small incisions in the abdomen, though which a graft is placed into the disc space, this is performed in order to treat lumbar spinal stenosis and associated conditions.

LEG PAIN – Problems in the lumbar spine (the five vertebrae in the lower spine between the ribs and the pelvis) may cause pain, weakness, or numbness in the legs, claves, or buttocks, or shooting pain in one or both thighs and legs, similar to sciatica.  For example, leg pain may be a symptom of lumbar spinal stenosis (narrowing of the spinal canal), which compresses the nerves traveling through the lower back into the legs, a degenerative condition that affects people age 60 and older.

LEUKODYSTROPHY – The disturbance of the white matter of the brain.

LIGAMENT - A white, shiny, flexible band of fibrous tissue that binds joints together and connects various bones and cartilage.

LINEAR ACCELERATOR – A machine that creates high-energy radiation to treat cancers, using electricity to form a stream of fast-moving subatomic particles.

LIPOMA - A benign fatty tumor, usually composed of mature fat cells.

LORDOSIS - A curvature of the spine with the convexity forward.

LUMBAR - The part of the spine between the thoracic spine and the pelvis.

LUMBAR DRAIN - A device, usually a long, thin, flexible tube, inserted through the skin into the cerebrospinal fluid of the lower back.

LUMBAR FUSION – A common surgery in the lumbar spine (the five vertebrae of the lower spine between the ribs and the pelvis) is called decompressive laminectomy during this surgery the lamina (roof) of the vertebrae is removed to create more space for the nerves.  A spinal fusion with or without spinal instrumentation may be recommended when spodylolistheses (slippage of one vertebrae over another) or scoliosis (curvature of the spine) occurs with spinal stenosis (narrowing of the spinal canal which compresses the nerves).  Various devices like screws, rods, and interbody devices may be used to enhance fusion and support unstable areas of the spine.

LUMBAR PUNCTURE (SPINAL TAP) – An invasive diagnostic test that uses a needle to remove a sample of cerebral spinal fluid (CSF) from the space surrounding the spinal cord.  This procedure can detect bleeding caused by a cerebral hemorrhage, disease conditions, deliver contrast dye to the spinal canal during diagnostic imaging, deliver anesthetic numbing agents to the spinal cord, can be used as a treatment to relive hydrocephalus, and during surgery to control CSF pressure and relax the brain.

M

MAGNETIC RESONANCE ANGIOGRAM (MRA):  This is a noninvasive study that is conducted in a Magnetic Resonance Imager (MRI).  The magnetic images are assembled by a computer to provide an image of the arteries in the patient’s head and neck.  The MRA shows the actual blood vessels in the neck and brain and can help detect blockage and aneurysms.

MAGNETIC RESONANCE IMAGING (MRI) – A diagnostic test that produces 3-D images of the body structures using magnetic fields and computer technology.  It can clearly show various types of nerve tissue and clear pictures of the brain stem and posterior (back) brain.  MRI of the brain can help determine whether there are signs of prior mini-strokes.  This test is noninvasive, although some patients may experience claustrophobia in the imaging “canal”.

MENINGES - The three layers of membranes covering the spinal cord and brain termed: dura mater, arachnoid mater and pia mater.

METASTATIC TUMOR – A tumor that is malignant and spread from cancer in other parts of the body.

MICROCATHETER - A very small catheter used to deliver diagnostic and therapeutic agents, such as embolic devices used in the endovascular treatment of cerebral aneurysms.

MICROELECTRODES - Thin metallic tubes inserted into the brain and guided by stereotactic methods. They are connected to the operating room computer and used to measure the electrical signal from brain cells during surgical procedures.

MICROGLIAL CELL - A type of immune cell found in the central nervous system. Microglia are scavengers, engulfing dead cells and other debris and act when the brain is damaged by invading injured regions and devouring/removing damaged cells.

MICROSURGERY - Surgery utilizing a microscope’s magnification to enable doctors to operate on very small areas. Microsurgery is used to target a specific area and to protect as much of the surrounding healthy tissue as possible.

MICROSURGERY EQUIPMENT & ENDOSCOPE TECHNOLOGY – See Endoscopy

MICROVASCULAR CLIPPING – In some cases of brain aneurysm, the neurosurgeon places a titanium clip or clamp where the aneurysm attaches to the artery.  This prevents blood from entering the aneurysm, and the aneurysm deflates, eliminating the chance of its rupture.

MILIARY ANEURYSM – An aneurysm that is tiny like a millet seed (about two millimeters in diameter). Miliary aneurysms tend to affect minute arteries in the brain or in the retina.

MINIMALLY INVASIVE MEDICAL TECHNOLOGIES (MIS) – Also called Endoscopic Technologies. A minimally invasive surgical procedure is defined as one that is carried out by entering the body through a natural opening or small incision in order to inflict the least amount of damage possible to surrounding tissues. Special medical equipment such as fiber optic cables, miniature video cameras (called endoscopes) and special surgical instruments are put in tubes inserted into the body via the small surface openings. The images of the interior body are then transmitted to an external video monitor. As an alternative to traditional surgery, MIS procedures reduce risk, pain, cost, procedure and recovery time. Due to these advantages, there is currently a powerful trend towards the development and adoption of more minimally invasive procedures.

MOTOR CORTEX – Also called Primary Motor. The motor cortex lies in the most posterior region of the frontal lobe. Nerves from the motor cortex carry signals to the brain stem and spinal cord, thus controlling and directing complex movements. Because the hemispheres control the body in a contra lateral fashion, nerves from the right motor cortex send signals to the left side of the body, while nerves from the left motor cortex send signals to the right side. Interestingly, the motor cortex is one section of the brain that can shrink or grow with time, as the size corresponds to how frequently a certain region (that corresponds to each body part) is used.

MOVEMENT DISORDER – Also called Motor System Disorder. Refers to several conditions, many of them neurodegenerative, that prevent normal movement. Some are characterized by either lack of movement (bradykinesia, hypokinesia, etc) or excessive movement (chorea, athetosis, dystonia, tremor). Besides Parkinson's, other conditions often defined as movement disorders include essential tremor, multiple system atrophy, progressive supranuclear palsy, Huntington's disease, Tourette's syndrome and cerebral palsy. MYELIN - The protective sheathing that insulates and protects nerve cell fibers in the brain, optic nerve, and spinal cord.

MYELOGRAM — An X-ray of the spinal canal following injection of a contrast material into the surrounding cerebrospinal fluid spaces.  It can show pressure on the spinal cord or nerves due to herniated discs, bone spurs, tumors, or stenosis.

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