MRI in Follow-up of Sciatica

Posted by Sara Fazio • March 15th, 2013

In patients with symptomatic lumbar disk herniation treated with surgery or conservative care, there was no significant association between findings on MRI and clinical outcome at 1 year. A new study shows that disk herniation persisted in 35% with a favorable outcome and 33% with an unfavorable outcome.

Magnetic resonance imaging (MRI) is frequently performed during follow-up in patients with known lumbar disk herniation and persistent symptoms of sciatica. The association between the findings on MRI and the clinical outcome is controversial.

Clinical Pearls

• What is the natural history of sciatica?

Sciatica is a relatively common condition with a lifetime incidence of 13 to 40%. The most common cause of sciatica is a herniated disk. The natural history of sciatica is favorable, with spontaneous resolution of leg pain within 8 weeks in the majority of patients.

 What was the association between the findings on MRI and the clinical outcome in patients being followed over time for sciatica?

In this study of patients with symptomatic lumbar disk herniation at baseline who were treated with either surgery or conservative treatment and followed for 1 year, the presence of disk herniation on MRI at 1-year follow-up did not distinguish patients with a favorable clinical outcome from those with an unfavorable outcome.

Table 3. MRI Findings According to Outcome at 1 Year.

Morning Report Questions

Q: What were the study results concerning nerve-root compression?

A: Nerve-root compression was observed significantly more frequently in patients who had received conservative treatment than in those who had undergone surgery (39% vs. 16%, P<0.001). As compared with baseline, root compression had disappeared in 82% of patients who had undergone surgery and in 60% of those who had received conservative treatment (P<0.001).

Q: How should one interpret scar formation on MRI?

A: The postoperative formation of epidural scars is a common phenomenon and is hypothesized to cause mechanical traction on the dura or nerve roots, resulting in persistent back and leg pain after spinal surgery. Some studies have supported this hypothesis, whereas other studies have not shown a correlation between epidural-scar formation and clinical outcome. The authors did not find a positive correlation between the presence of scar tissue and symptoms. They indicate that clinicians should not automatically ascribe recurrent or persistent symptoms to visible scar formation on MRI.

3 Responses to “MRI in Follow-up of Sciatica”

  1. Alexandros Zachos says:

    There are studies which proves changes (MRI) of the Hydration of the lumbar disk. The treatment with interspinous spacer can change the MRI one year after

  2. Dr Sanjiv Desai says:

    I believe a thorough pre op assessment is in order. Unless there is a significant neurological deficit, surgery, only on basis of pain, should never be offered. Conservative management for pain should suffice.
    A proper sensory-motor deficit is only likely to relieve the problem post surgery.

  3. Steve Lockhart says:

    In my years of treatment I have discovered a large percentage of sufferers dealing with muscle imbalances not supporting the spine correctly and applying pressure to the spine.

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