MRI of herniated nucleus pulposus : correlation with clinical findings, determinants of spontaneous resorption and effects of anti-inflammatory treatments on spontaneous resorption
Autio, Reijo (2006-05-16)
The purpose of the current study was to evaluate the intercorrelations of magnetic resonance imaging (MRI) findings and clinical symptoms and signs in sciatic patients. Furthermore, determinants of spontaneous HNP resorption and the effect of anti-inflammatory treatments (periradicular methylprednisolone injection and intravenous infliximab) on spontaneous HNP resorption were evaluated.
MRI follow-up was performed at baseline, after two months, after six months and after one-year for patients with unilateral sciatica to evaluate determinants of spontaneous HNP resorption and the effect of periradicular methylprednisolone injection on spontaneous HNP resorption. At baseline the study population consisted of 160 patients (group A).
MRI follow-up for 21 patients with unilateral sciatica was performed at baseline and after two weeks, after three months and after six months to evaluate the effect of infliximab, a monoclonal TNFα antagonist, infusion on spontaneous HNP resorption (group B).
Patients in group A were randomized to receive either periradicular saline or methylprednisolone. Volume of HNP, extent and thickness of enhancement (in Gd-DTPA MRI) and degree of disc displacement were measured and the symptoms and signs were followed repeatedly. The extent of rim enhancement correlated significantly with the degree of disc displacement. The duration of sciatic symptoms correlated negatively with enhancement parameters. The clinical symptoms did not correlate significantly with the different enhancement parameters or disc herniation volume. Achilles reflex abnormality correlated significantly with all enhancement parameters for lesions at L5-S1.
Significant decrease in HNP volume occurred from baseline to two moths, and even more so during the whole one year follow-up period. Higher baseline scores of rim enhancement thickness, higher degree of HNP displacement in the Komori classification and age category of 41–50 years were associated with a higher resorption rate. Clinical symptoms alleviation occurred concordantly with a faster resorption rate.
No significant difference was noted in the decrease of HNP volume in the saline and methylprednisolone injection groups in follow-up imaging during one year. The enhancement parameters (thickness and extent of rim enhancement) did not differ significantly in the different treatment groups.
In group B, 11 patients received intravenous infliximab and 10 saline. Baseline demographic data, pain scores, and clinical status, did not differ between the treatment groups. HNP volume decreased significantly in both groups (P < 0.01). There was no significant difference in HNP volume changes between the treatment groups. By two weeks, enhancement thickness increased significantly in the infliximab compared placebo group (p=0.003). Two patients in each group required back surgery prior to the 6-month assessment.
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