Effectiveness of Diagnostic Tools for Sciatica

Question: Discogram, CT scan, or myelogram for sciatica diagnosis?

Since a spinal fusion surgery eight years ago, all activities and exercise create sciatica pain. The leg numbness and tingling and aching from the sciatica are so bad they sometimes wake me at night.

My surgeon has just suggested a discogram and CT scan. I’m avoiding a myelogram because it caused a severe headache the last time I had one performed.

Will the information from the discogram and CT scan be as good as that derived from a myelogram? Which is the most effective test for my situation?

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Doctor’s response: Each test provides different information

A CT scan, discogram and myelogram are completely different tests providing different information. The myelogram is better for identifying a pinched nerve that may be causing the sciatica. This is important if the pain is primarily in the legs or if there is any leg weakness with the leg numbness and tingling. A discogram is a provocative test that is designed to tell if the front of the disc space is still a cause of pain.

Having a headache after one myelogram does not necessarily mean that you will have one again. However, both the tests will have to go through the thecal sac, which is what usually gives you the myelogram headache.

Usually the discogram can be done from the side, but after a spinal fusion, often the only way to get in the disc space is through the thecal sac. Therefore, either test may give you a spinal headache, so choosing a discogram to avoid a spinal headache is not reasonable.

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In Spine-health’s Doctor Advice section, physicians respond to frequently asked questions about back pain issues. These responses represent the opinion of one physician, and do not necessarily reflect the views of the broader medical community. The advice presented has not been peer reviewed by Spine-health’s medical advisory board.

Written by Medical Reviewer