Your referring physician has requested that you have a cervical (or cervical plus thoracic/lumbar) myelogram. The following is a description of the procedure and a description of the potential complications, so that you may provide informed consent prior to the procedure.
A myelogram is an invasive procedure with some uncommon risks. After local anesthesia, a needle will be placed with fluoroscopic (x-ray) guidance into the spine and into the fibrous sac containing spinal fluid, spinal cord, and nerve roots. Fluid may be withdrawn (if necessary) for routine laboratory tests, and then myelogram contrast (x-ray dye) will be injected into the spinal fluid. Radiographs (x-rays) will be taken, and then you will have a CT (or CAT scan) of the spine, typically done within an hour or two of the myelogram. Afterwards, you will then be monitored for potential complications in the hospital until you are discharged, usually 4 hours after the procedure. You will be able to eat and drink as well as use the bathroom while in the hospital after the procedure.
In cervical myelograms, the needle is typically placed in the lumbar/lower spine and the contrast is moved into the cervical spine by tilting the table down. It may also rarely be injected directly into the cervical spine in the upper neck below the skull. Cervical puncture may lead to improved myelogram pictures in certain patients. In addition, cervical puncture has a benefit – the most common complication of lumbar puncture, a spinal headache, almost never happens with cervical punctures. However, cervical punctures do have additional potential complications than standard lumbar punctures. Most complications of myelograms are rare (except for spinal headache) and the procedure is very safe. You need to know the potential complications which include:
- BLEEDING. As with all needle procedures, bleeding can occur. As long as you have no bleeding tendency and are not on any blood thinners such as Coumadin or Plavix, bleeding complications are extremely rare. Rarely, patients have had to undergo emergency surgery to relieve pressure on the nerve roots and spinal cord because of bleeding after spinal needle procedures like myelograms.
- INFECTION. Any needle passing through the skin can introduce infection, so there is a rare risk of infection such as meningitis. Meningitis is an extremely rare complication, and sterile technique will be used during the procedure to minimize this risk.
- SEIZURE. The injected contrast into the spinal fluid is absorbed around your brain in the first day and can be irritating. Some patients will complain of a mild headache, for which your nurse may give you pain medicine after the procedure if necessary. The contrast can also increase the risk of seizures. Although this risk can rarely happen to anyone, the risk is greater in patients with history of seizures/epilepsy. If you have such a risk, please tell the staff and radiologist and do not stop any prescribed anti-seizure medication. This is very rare complication, but is the reason that you will be monitored in the hospital for a few hours. Valium, may be given to you orally prior to the procedure in certain cases to reduce the risk of a seizure. Valium also has a mild sedative effect. You should not be currently taking any medications that may make seizure more likely, particularly the antidepressant Elavil/amitriptyline. Typically any such medication will be held for 2 days before and 2 days after the procedure but at times exceptions are made, depending on the medication. Patients with known epilepsy taking anti-seizure medication, MAY have a myelogram but must be aware of the potential risk of inducing a seizure. An IV catheter may be placed prior to the procedure in patients felt to be at high risk for seizure.
- SPINAL HEADACHE. Spinal headache is the most common complication, and occurs if the small hole in the fibrous sac does not completely close after the needle puncture. The spinal fluid can then leak out, and if significant, the brain loses the cushioning effect of the spinal fluid which causes a severe headache when you sit or stand. Spinal headaches have been reported in up to 30-40% of patients after a lumbar puncture of any kind including myelogram. Typically they occur about 1-2 days after the procedure. These headaches are usually very positional, meaning they start when you sit or stand and go away when you lie down. It is important that you follow instructions to stay on bedrest only getting up to go to the bathroom for 24 hours after your myelogram, and to drink plenty of fluids. The bed rest is important to allow the small hole in the sac to heal and close. If you develop a spinal headache, it is OK to treat yourself. As long as you do not feel ill, do not have a fever, and the headache goes away when you lie down, you may treat yourself with another day of bed rest with bathroom privileges and drinking plenty of fluids. Caffeine often helps with these headaches as well, if your doctor normally allows you to have caffeine. These simple actions almost always work. If not, please contact the radiologist who performed the procedure. Uncommonly a procedure called an epidural blood patch may be performed in the hospital with a very high success rate in treating spinal headaches that don’t resolve with bedrest. This procedure is only done in about 1% or less of patients after a myelogram.
- INJURY TO THE SPINAL CORD OR VERTEBRAL ARTERY. These are potential complications only of cervical punctures and are very rare. The needle is placed into a small space immediately behind the spinal cord with the needle puncturing the skin just behind the ear below the skull. If the needle does not go where it is intended, particularly if the patient moves during the puncture, it can puncture the spinal cord or injure an artery supplying the back of the brain, called the vertebral artery. If the needle touches the spinal cord, nothing happens except for some pain. However, if contrast (x-ray dye) is injected into the cord, serious complications can occur. An injured vertebral artery could lead to a stroke. For these reasons, cervical punctures are only performed by experienced physicians, typically a neuroradiologist.
- ALLERGIC REACTION: The use of any medication, including x-ray contrast, has the possibility of producing an allergic reaction. Please inform your physician of all of your known medical allergies before the procedure.
Please feel free to ask any questions you may have about the procedure prior to signing the consent form.