IDET™
INTRADISCAL ELECTROTHERMAL™ Therapy
Differential Diagnosis
With so many possible causes of lower back pain, physicians must pinpoint the source(s) of pain to recommend appropriate action or no action. The IDET◊ procedure is not suitable for every form of lower back pain. Chronic discogenic lower back pain unresponsive to aggressive non-operative therapy is the principal indication for the IDET◊ procedure.
- Differential diagnosis starts with a detailed history, physical examination and an MRI.
- Non-musculoskeletal causes of back pain such as tumor, infection, aneurysm and renal and vascular pathology should be considered and ruled out.
- Fractures and ankylosing spondylitis should also be ruled out.
- Discogenic pain should be differentiated from radicular pain, which may also be present.
Characteristics
of discogenic pain |
Characteristics
of radicular pain |
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- Intense, severe, hot burning, knife-like pain
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- Back pain is worse than leg pain
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- Limb pain is much more significant than back pain
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- Radiation of pain to buttocks or backs of thighs
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- Exacerbation by coughing, sneezing, or lifting
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- Somatic referred pain (not radicular)
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- MRI shows disc herniation/prolapse or spinal stenosis
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- No associated herniation or prolapse of disc material on MRI
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- Pain produced by chemical irritation from a disc protrusion/prolapse or mechanical pressure from canal or spinal stenosis
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- No nerve root irritation, radicular pain, or neurological deficit
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MRI results will be helpful in identifying disc abnormalities producing radicular pain. However, these results may not help physicians make a conclusive distinction between predominantly discogenic and predominantly radicular pain.
- Pain which is unilateral and predominantly below lumbar vertebra 5 is probably not discogenic.
- Diagnostic joint blocks can be used to trace the source of pain, which can be attributed to the sacroiliac joint in about 20% of patients and lumbar zygapophysial joint pain in up to 40% of patients.
- Patients with discogenic pain may have no abnormalities visible on the MRI or may have a bright spot in the posterior anulus referred to as the high intensity zone or HIZ. This is best seen on sagittal views and indicates a tear in the disc.
Discography is a minimally invasive diagnostic procedure performed while the subject is awake. Sedation and analgesia can be provided to minimize discomfort. Contrast medium is injected into the three or four discs under investigation as the source of the low back pain.
- The injection of fluid into each disc increases the fluid volume and pressure in the disc and may reproduce the subject’s usual pain pattern.
- A positive response in one disc confirmed by the absence of a pain response in one or more other adjacent discs confirms the origin of the pain.
- In addition, the contrast medium allows the morphology of the disc to be visualized fluoroscopically.
Since provocation discography is minimally invasive and produces some discomfort, it should only be performed when a definitive diagnosis will lead to treatment that would otherwise not be performed.
The disc which is the source of the low back pain can be confirmed when:
- The pain elicited is similar to patient’s usual pain pattern.
- At least one adjacent disc (preferably two) does not reproduce pain.
