A myelogram is a specialized diagnostic imaging procedure that uses a contrast material to provide detailed pictures of the spinal canal, including the spinal cord, nerve roots, and surrounding tissues. This technique is used when standard imaging (X-ray, CT, or MRI) does not clearly identify the cause of chronic back or leg pain. The procedure involves injecting a radiopaque dye into the subarachnoid space (the fluid-filled space around the spinal cord). This dye allows structures to show up clearly on subsequent X-ray or CT images, helping diagnose conditions such as herniated discs, spinal stenosis, spinal tumors, and nerve root compression.
Preparing for the Myelogram
Patients are asked to arrive at the facility 30 to 60 minutes before the scheduled procedure time for intake and preparation. This initial period is used for patient registration, verifying identification, and signing consent forms.
The medical team reviews the patient’s history, focusing on allergies to the contrast dye or local anesthetics. They also discuss medications that may need to be temporarily stopped, such as blood thinners or certain antidepressants. The patient then changes into a gown and is positioned on the examination table.
Duration of the Imaging Procedure
The actual imaging procedure, from preparation on the table to final image acquisition, typically takes between 30 and 60 minutes. The process begins with cleaning the injection site, usually in the lower back, with an antiseptic solution. A local anesthetic is then administered to numb the skin, which may cause a brief stinging sensation.
Once the area is numb, a thin needle is inserted between the vertebrae into the subarachnoid space, requiring the patient to remain very still. The contrast dye is slowly injected, sometimes after a small amount of cerebrospinal fluid is removed. The table may be tilted to help the contrast material flow to the specific area being examined. The radiologist uses fluoroscopy (real-time X-ray) to observe the dye’s path and take a series of static images.
Required Post-Procedure Monitoring
The time spent in post-procedure monitoring is often longer than the imaging itself. After the needle is removed and a bandage is applied, the patient is moved to a recovery area for observation. This monitoring is designed to minimize the risk of a post-dural puncture headache, a side effect caused by cerebrospinal fluid leakage from the injection site.
Patients are typically required to lie flat or keep their head slightly elevated for one to six hours; many facilities require two to four hours of bed rest. During this time, nurses monitor vital signs and watch for immediate adverse reactions to the contrast dye. Drinking extra fluids is encouraged immediately to help the body replace lost spinal fluid and flush the contrast dye out of the system.
What Can Affect the Overall Timeline
Several factors can introduce variability to the standard myelogram timeline, potentially extending the total time spent at the facility. Anatomical challenges, such as severe arthritis, spinal stenosis, or previous spinal surgery, can make the initial spinal tap difficult for the radiologist. If the injection site is hard to locate, the procedure time may be prolonged beyond 60 minutes.
A common addition that extends the overall process is the immediate post-myelogram CT scan, often called a CT myelogram. This combination is frequently ordered to provide more detailed cross-sectional images after the contrast is injected. While the initial myelogram may take 30 minutes, the subsequent CT scan adds 15 to 30 minutes to the imaging time. Minor side effects, such as persistent headache or nausea, may also necessitate a longer stay in recovery for additional monitoring or treatment.