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Houston, Texas

A full range of modern neurosurgical specialties and techniques are provided by top BCM neurosurgery specialists.
Department of Neurosurgery
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Definitions O-Z

Occipital Neuralgia
Pain syndrome located in the upper neck or back of the head caused by irritation of the occipital nerve. Treatment can consist of medication therapies, or lesioning of the nerve (either by cutting it or by heating it). Appropriate investigations should be performed to rule out other causes of pain from that region.

Osteoporotic Vertebral Compression Fracture
Osteoporosis results in the progressive mineral loss from the bone and changes within the bony architecture, leaving the bones weakened structurally and therefore more subject to fractures. The vertebral bodies, as a major load bearing structure, are particularly prone to fracture. Vertebral compression fractures secondary to osteoporosis usually occur after minor trauma or spontaneously.

Parkinson's Disease
Neurodegenerative disorder caused by the loss of cells that produce a chemical called dopamine. The hallmark of Parkinson's disease is a resting tremor, slowness of movement (bradykinesia), and limb rigidity. Most patients respond to medical therapy but over time the disease can advance. Surgical treatments for Parkinson's disease include brain lesioning (thalamotomy or pallidotomy), deep brain stimulation and new approaches such as experimental transplantation.

Pineal Tumor
The pineal gland is a small structure in the middle of the brain. Primitive tumors can grow in this region often related to developmental body cells (germ cells). Tumors such as germinomas or non-germanomatous germ cell tumors can cause headaches, hydrocephalus or other neurologic symptoms. Treatments can consist of open resection, endoscopic biopsy, stereotactic biopsy, radiation therapy, focused radiation and chemotherapy. Because different tumors can occur in this area, it is important to guide treatment based upon the individual tumor type.

Pituitary Adenoma
A benign tumor. A pituitary gland, responsible for secretion of hormones, can form a tumor. A pituitary adenoma can cause an over secretion of hormones and cause problems such as acromegaly (growth hormone hypersecretion), Cushing's disease (corticosteroid hormone hypersecretion). Prolactinoma refers to a tumor that over secretes prolactin. This often leads to galactorrhea (secretion of milk from breast tissue). If a tumor grows to a large size, it can cause a compression of the optic system leading to visual deficits. Treatments can consist of surgical resection, either through the nose (transsphenoidal surgery) or through the cranium, or radiation approaches.

The irritation of a nerve root at any level of the spine. Radiculopathy can be caused by protrusion of a disk, by arthritis of the spine or by compression from an offending tumor or other process. Radiculopathies can cause pain or neurologic deficits.

Reflex Sympathetic Dystrophy (causalgia)
Pain syndrome often after prior limb injury. The painful limb becomes cold and often associated with increased sweating. Certain medications can help but in some patients, an operation called sympathectomy may be necessary.

Overgrowth (tumor) of Schwann cells. Schwann cells are responsible for providing the insulation (myelin) for nerves. Schwannomas can occur in the brain, the spine, or the limbs (peripheral nerves). A common brain schwannoma is the vestibular schwannoma (acoustic neuroma), which can lead to hearing loss. Multiple schwannomas can be seen in the setting of neurofibromatosis type 1. Treatment often consists wither of a surgical resection or irradiation.

An electrical brain disturbance that leads to a convulsion or other transient neurologic problem. Some seizures may consist only of staring spells. Other can consist of temporary smells or tastes. Other seizures can involve jerking limb movements or numbness. An investigation should be performed to try to identify the cause of the seizures. Medication therapy may be necessary in some patients and occasionally surgery is performed to relieve the seizure focus.

A shunt system is used to divert cerebral spinal fluid from the brain to another body compartment. This is usually used to treat hydrocephalus. Shunts can be used to divert fluid from the cerebral ventricles to the abdomen (ventricular peritoneal shunt) or to the chest (ventricular pleural shunt).

Skull Fracture
Fractures of the skull bone (cranium) can occur after mild or severe head injury. A skull fracture may be associated with no symptoms or a mild headache. Other factors can be followed by concussion syndromes or more severe brain injury. An open skull fracture is one in which the overlying skin has also been opened up. A depressed skull fracture is when one of the bony fragments is compressing the brain structures.

Involuntary muscle tightness and stiffness that occurs in about two-thirds of people with cerebral palsy and in many who suffer severe head injuries. The medical definition of dystonia is a velocity-dependent, increased resistance to passive muscle stretch. In other words, when a muscle affected by spasticity is stretched by someone else, it is harder to move the muscle than normal, and the faster one pushes, the harder the muscle is to move.

Spinal Cord Arteriovenous Malformation (SC-AVM)
Arteriovenous malformations or AVMs are vascular irregularities that are comprised of arteries and veins that are connected differently than they are in other areas of the body. They are congenital (from birth), rare in the spine, and usually diagnosed with MRI. Spinal cord AVMs can cause symptoms by compressing the spinal cord or by bleeding. They can be treated by observation, a procedure call embolization, and / or surgical resection.

Spinal Fracture
A fracture of any element of the spinal column can lead to pain, neurologic deficit or in some patients, no symptoms at all. Spinal fractures usually occur after some kind of injury. If the spinal bones are unstable, fixation may be required.

Spinal Instability
Certain disorders can lead to excessive movement between one or more spinal bones. An unstable spine can place the nerves or spinal cord at risk for injury. Spinal instability can occur with certain diseases such as rheumatoid arthritis, or after spinal injury. Instability can be managed with an external brace (i.e. a collar), or with surgical fixation. Spinal stenosis refers to a narrowing of the spinal column caused by an excessive overgrowth of the spinal bones, ligaments or other tissues. Spinal stenosis can cause pain or progressive neurologic deficits.

Spinal Tumor
Tumors of the spine can be either benign or malignant. Benign tumors include schwannomas, neurofibromas and meningiomas. Malignant tumors are most commonly caused by cancers that spread from other body areas (i.e. lung, breast, kidney or skin cancer). Tumors of the spinal cord itself can be either benign or malignant. Treatment can consist of radiation surgery or combined approaches depending on the tumor type.

Temporary or permanent loss of the blood supply to the brain (thrombotic stroke), or acute bleeding in the brain (hemorrhagic stroke). Strokes cause sudden neurologic deficits that can be mild or severe. When symptoms recover promptly, a patient may have had a transient ischemic attack. When symptoms last for more than 24 hours, a stroke is said to have occurred. Strokes or neurosurgical emergencies in patients should be brought to the hospital as soon as possible. Investigations include brain scans, special blood flow studies, and sometimes tests that show the caliber of blood vessels (angiograms).

Subdural Hematoma
Blood clot that occurs on the surface of the brain and just below the dura (covering of the brain). A subdural hematoma usually occurs from the tear of one of the veins that drain the brain of blood. Subdural hematomas can be either acute (after a recent injury), or chronic (after an old and sometimes unforgotten, even minor or trivial) head injury. Chronic subdural hematomas can be managed with close observation or if the blood clot is sizable, with drainage via burr holes. Acute subdural hematomas usually require an open craniotomy to evacuate the blood clot.

This tumor refers to a cavity of fluid that occurs within the spinal cord. The cavity can enlarge slowly and may lead to pain, loss of sensation in the limbs or weakness. They can be found after injury, in relation to tumors or of unknown cause.

Ringing in the ears sometimes caused by compressed blood vessels.

Traumatic Brain Injury
This term refers to the effects on the brain after head injury. Traumatic brain injuries can lead to a spectrum of problems including concussion, contusion (hemorrhage within the brain), or diffuse injuries that cause more severe neurologic deficits.

Trigeminal Neuralgia
Sharp shooting lancinating pain found in the forehead, face or jaw region. The pain is usually on only one side of the face. It can sometimes be seen in the setting of multiple sclerosis. Treatment usually consists of medical therapy (the primary drug is Tegretol ). In patients who are refractory to mediation therapy or have side effects, different surgical approaches such as microvascular decompression, percutaneous rhizotomy (glycerol, radiofrequency or balloon technique) or stereotactic radiosurgery can be performed.

Ulnar Neuropathy
Compression or irritation of the nerve at the elbow. This is sometimes called the "funny bone" and compression of the nerve causes numbness in the little finger and ring finger. Weakness may also be noted.

Venous Malformation
Collection of veins within the brain that look abnormal on a brain scan. The veins however perform their normal function in that they drain blood from the brain back to the heart. They are usually not symptomatic and most patients require no treatment.

Vertebral Compression Fracture
Fracture of the vertebral body. There is usually an acute onset of severe back pain. This back pain, depending on the severity of the fracture, can be mild to severely debilitating. In addition to severe pain, vertebral compression fractures frequently cause malalignment of the spine.

Sense of spinning or feeling of disequilibrium. It is often accompanied by nausea and occasionally vomiting and is generally worsened by motion. Sometimes caused by blood vessel compression of balance nerves.

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