Type of Surgery
Last updated: 11/24/2009
The purpose of a myelogram is to evaluate the spinal cord and nerve roots for suspected compression. Pressure on these delicate structures causes pain or other symptoms. A myelogram is performed when precise detail about the spinal cord is needed to...
make a definitive diagnosis. In most cases, myelography is used after other studies, such as magnetic resonance imaging (MRI) or a computed tomography scan (CT), have not provided enough information to be certain of the diagnosis. Sometimes myelography followed by CT scan is an alternative for patients who cannot have an MRI scan, because they have a pacemaker or other implanted metallic device.
A herniated or ruptured intervertebral disc, or related condition such as disc bulge or protrusion, popularly known as a slipped disc, is one of the most common causes for pressure on the spinal cord or nerve roots. The condition is popularly known as a pinched nerve. Discs are pads of fiber and cartilage that contain rubbery tissue. They lie between the vertebrae, or individual bones, which make up the spine.
Discs act as cushions, accommodating strains, shocks, and position changes. A disc may rupture suddenly, due to injury or a sudden strain with the spine in an unnatural position. In other cases, the problem may come on gradually as a result of progressive deterioration of the discs with aging. The lower back is the most common area for this problem, but it sometimes occurs in the neck, and rarely in the upper back. A myelogram can help accurately locate the disc or discs involved.
Myelography may be used when a tumor is suspected. Tumors can originate in the spinal cord or in tissues surrounding the cord. Cancers that have started in other parts of the body may spread or metastasize in the spine. It is important to precisely locate the mass causing pressure so effective treatment can be undertaken. Patients with known cancer who develop back pain may require a myelogram for evaluation.
Other conditions that may be diagnosed using myelography include arthritic bony growths (spurs), narrowing of the spinal canal (spinal stenosis), or malformations of the spine.
Normal Pressure Hydrocephalus or NPH is described in this animation showing the ventricles of the brain and the flow of cerebrospinal fluid or CSF. The cause is not precisely known but can caused nausea, vomiting, headache, and problems walking among other symptoms.
Myelography is a type of radiographic examination that uses a contrast medium to detect pathology of the spinal cord, including the location of a spinal cord injury, cysts, and tumors. The procedure often involves injection of contrast medium into the cervical or lumbar spine, followed by several X-ray projections. A myelogram may help to find the cause of pain not found by an MRI or CT. Myelography has been largely replaced by the use of CT and MRI scans.
A CT is typically performed after myelographic material has been placed with fluoroscopic guidance. A CT myelogram is most useful for patients who cannot undergo MRI (eg those with pacemakers or cochlear implants) or for those in whom MRI provides limited information (eg those with extensive metal in the spine).
More than 60 percent of procedures neurosurgeons perform are spine-related, according to the National Neurosurgical Procedural Statistics 2006 Survey from the American Association of Neurological Surgeons (AANS).
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