Type of Surgery
Last updated: 11/24/2009
Myelograms can be performed in a hospital x ray department or in an outpatient radiology facility. The patient lies face down on the x ray table. The radiologist first looks at the spine under fluoroscopy, and the images appear on a monitor screen....
This is done to find the best location to position the needle. The skin is cleaned, numbed with local anesthetic, and then the needle is inserted. Occasionally, a small amount of cerebrospinal fluid, the clear fluid that surrounds the spinal cord and brain, may be withdrawn through the needle and sent for laboratory studies. Contrast material (dye that shows up on x rays) is then injected.
The x-ray table is tilted slowly, allowing the contrast material to reach different levels in the spinal canal. The flow is observed under fluoroscopy, and x rays are taken with the table tilted at various angles. A footrest and shoulder straps or supports keep the patient from sliding.
In many instances, a CT scan of the spine is performed immediately after a myelogram, while the contrast material is still in the spinal canal. This helps outline internal structures more clearly.
A myelogram takes approximately 30 to 60 minutes. A CT scan adds about another hour to the examination. If the procedure is done as an outpatient exam, some facilities prefer the patient to stay in a recovery area up to four hours.
Patients who are unable to lie still or cooperate with positioning should not have this examination. Severe congenital spinal abnormalities may make the examination technically difficult to carry out. Patients with a history of severe allergic reaction to contrast material (x-ray dye) should report this to their physician prior to having myelography. Medications to minimize the risk of severe reaction may be recommended before the procedure. Given the invasive nature and risks of myelograms and increased anatomic detail provided by MRI or CT, myelograms are generally not used as the first imaging test.
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).
For a neurosurgery, as for any other surgery, it's important to always bring x-rays and any other medical records the patients has.
-Dr Catherine McAuley
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