A myelogram is a specialized diagnostic imaging procedure that uses X-rays or a Computed Tomography (CT) scan after a contrast dye is injected into the fluid surrounding the spinal cord. This procedure allows physicians to examine the spinal canal, nerve roots, and other structures more clearly than conventional imaging alone. While minimal sedation to reduce anxiety may be available, deep or general sedation is almost always avoided during this test. This limitation is related to the steps required to successfully complete the imaging.
What Happens During a Myelogram
The procedure typically begins with the patient lying on an X-ray table while the skin on the lower back is sterilized. A local anesthetic is administered to numb the area where the needle will be inserted, though the patient may still feel pressure. Using fluoroscopy, a real-time X-ray technique, a thin needle is inserted into the subarachnoid space containing the cerebrospinal fluid (CSF) that surrounds the spinal cord.
A small amount of CSF may be removed for testing before the iodine-containing contrast dye is injected through the same needle. The contrast agent mixes with the CSF, highlighting the neural structures for the imaging scans. To ensure the dye flows to the specific area being examined, the X-ray table is slowly tilted while the patient is secured with a harness or brace. This tilting and the subsequent taking of images, including a CT scan, requires the patient to remain still or follow instructions to move slightly so the radiologist can capture a complete set of diagnostic images.
Why Sedation is Usually Limited
The primary reason deep sedation or general anesthesia is rarely used is the necessity of patient responsiveness during the procedure. Since the imaging table is tilted to move the contrast dye, the patient must be alert enough to follow instructions, adjust their position, and remain still to prevent blurring of the images. A deeply sedated person cannot reliably assist with this requirement.
The procedure involves placing a needle close to the nerve roots. If the needle tip irritates a nerve, the patient may feel a radiating sensation, often described as an electric shock. The ability to immediately report this sensation is crucial, as it allows the radiologist to adjust the needle’s position to prevent nerve injury. Deep sedation would mask this protective neurological feedback.
Heavy sedation carries general risks, such as the potential for aspiration, especially when lying flat or prone on the imaging table. The contrast agent can also cause rare but serious complications, including seizures. A fully awake patient allows for immediate assessment and intervention if any adverse reaction occurs. The goal is to keep the patient calm and comfortable, but fully conscious and able to communicate.
Alternatives for Managing Procedure Anxiety
While deep sedation is avoided, options are available to manage nervousness and anxiety before and during the myelogram. Many facilities permit the use of oral anti-anxiety medications, such as a benzodiazepine, taken shortly before the procedure. These medications promote minimal or conscious sedation, making the patient relaxed and drowsy while still allowing them to follow commands.
In some cases, a mild intravenous (IV) sedative may be administered by the assisting nurse to induce a state of calm alertness. Non-pharmaceutical techniques are also employed to reduce anxiety. These techniques involve providing clear, detailed information about the procedural steps beforehand to reduce fear of the unknown. Additionally, the presence of a supportive and communicative staff member can provide continuous reassurance throughout the exam.
Immediate Care After the Procedure
After the needle is removed and the images are taken, a mandatory period of recovery and observation is required to prevent potential complications. Patients are typically asked to lie flat or with their head slightly elevated for a period ranging from two to six hours to allow the puncture site in the dura mater, the membrane surrounding the spinal cord, to seal. This resting period is the most effective way to minimize the risk of a post-spinal headache, which is caused by a small leak of cerebrospinal fluid.
During this recovery time, patients are strongly encouraged to increase their fluid intake. Hydration helps replace the small amount of CSF that may have been lost and assists the body in flushing the contrast dye. You will be monitored for signs of complications, including severe headache, nausea, or any new symptoms like leg weakness or numbness. Strenuous activities and heavy lifting should be avoided for at least 24 hours.