Correlation between persistent neurological impairment and clinical outcome after microdiscectomy for treatment of lumbar disc herniation.

Background: Outcome of lumbar disc herniation is often based on clinical scores and less frequently on the neurological examination. However, even when clinical outcome measures are favorable, patients may still experience motor or sensory impairment.

Objective: To evaluate the percentage of patients with persistent neurological deficits after lumbar disc surgery and whether these correlate with clinical outcome.

Methods: A total of 150 patients with sciatica and lumbar disc herniation with neurological impairment underwent microdiscectomy and were prospectively followed for 24 months. Patients were assessed pre- and postoperatively with neurological examination, the Oswestry Disability Index (ODI), and the visual analog scale (VAS) for pain.

Results: Twenty-four months after surgery, 25% of patients who presented with motor deficits, 40% of patients with sensory deficits, and 48% of patients with reflex abnormalities remained unchanged. The VAS and the ODI showed significant improvement in both patients with and without persistent neurological impairment immediately after surgical repair of the herniated disc with progressive improvement over the follow-up period. However, when calculating the area under the receiver operating characteristics curve, no statistically significant correlation could be established between the presence and persistence of neurological impairment and the 2 clinical scores.

Conclusion: There seems to be no correlation between clinical results and neurological impairment when assessed by the VAS and ODI.