The effect of infliximab, a monoclonal antibody against TNF-alpha, on disc herniation resorption: a randomized controlled study

STUDY DESIGN

Randomized, controlled study.

OBJECTIVE

To evaluate the effect of infliximab on herniated nucleus pulposus (HNP) resorption.

SUMMARY OF BACKGROUND DATA

Although the effects of tumor necrosis factor alpha (TNF-alpha) on HNP resorption are not fully understood, TNF-alpha appears to be an essential mediator in HNP resorption.

METHODS

As part of a substudy of the FIRST II study, magnetic resonance images (MRIs) were obtained from 21 patients who were candidates for discectomy at weeks 0, 2, 12, and 26 after receiving a single infusion of either 5 mg/kg infliximab (11 patients) or placebo (10 patients). The volume (mm3) of HNP, thickness (mm) and extent (%) of rim enhancement, and presence of nerve root edema were assessed.

RESULTS

HNP volume decreased significantly from baseline to 6 months in both treatment groups (P < 0.01), with no difference noted between the infliximab and placebo groups. By week 2, rim enhancement thickness increased significantly in the infliximab group compared with the placebo group (P = 0.003). Two patients in each group required back surgery before the 6-month assessment.

CONCLUSIONS

Infliximab did not appear to interfere with disc herniation resorption over a 6-month period.

Determinants of spontaneous resorption of intervertebral disc herniations

STUDY DESIGN

A follow-up of disc herniation (herniated nucleus pulposus [HNP]) resorption on magnetic resonance imaging (MRI).

OBJECTIVE

To assess the determinants of resorption of HNP.

SUMMARY OF BACKGROUND DATA

Neovascularization in the outermost areas of HNP, presenting as an enhancing rim in gadolinium diethylenetriamine pentaacetic acid MR images, is thought to be a major determinant of spontaneous resorption of HNP.

METHODS

Patients with HNP-induced sciatica at baseline were rescanned at 2 months (N = 74) and after 12 months (N = 53). The volume of HNP (mm), thickness (mm) and extent (%) of enhancement, and the degree of HNP migration (Komori classification) were analyzed. Repeated measures analysis of covariance was used in statistical analysis.

RESULTS

Significant resorption of HNP occurred from baseline to 2 months, although the resorption rate was more pronounced over the whole 1-year follow-up. Higher baseline scores of rim enhancement thickness, higher degree of HNP displacement in the Komori classification, and age category 41-50 years were associated with a higher resorption rate. Thickness of rim enhancement was a stronger determinant of spontaneous resorption than extent of rim enhancement. Clinical symptom alleviation occurs concordantly with a faster resorption rate.

CONCLUSIONS

MRI is a useful prognostic tool for identifying patients with HNP-induced sciatica with a benign natural course.

Effect of periradicular methylprednisolone on spontaneous resorption of intervertebral disc herniations

STUDY DESIGN

Prospective comparison of periradicular infiltration with steroid versus saline on the spontaneous resorption of herniated nucleus pulposus in a randomized controlled trial.

OBJECTIVES

To evaluate whether periradicular steroid retards the resorption of herniated nucleus pulposus.

SUMMARY OF BACKGROUND DATA

Rim enhancement around herniated nucleus pulposus is associated with spontaneous resorption of disc herniations. As rim enhancement consists of a macrophage infiltrate, periradicular steroid could theoretically interfere with the resorption process. METHODS.: Patients with disc herniation-induced sciatica were randomized to receive either periradicular methylprednisolone (in combination with bupivacaine) or saline. Lumbar magnetic resonance imaging (MRI) was performed at baseline, at 2 months, and at 12 months. Disc herniation volume (mm3), coverage of rim enhancement (%), and rim enhancement thickness (mm) were evaluated by a radiologist blinded to the allocation. Operated patients were excluded from the 1-year imaging. Changes in the parameters from baseline to 2 months, and from 2 to 12 months, were evaluated with the Mann-Whitney U test.

RESULTS

Change in herniation volume from baseline to 2 months was measurable in 34 patients of both groups, and from 2 to 12 months in 26 patients of the steroid group and 24 patients of the saline group. Significant spontaneous resorption of disc herniations occurred in both groups during the 1-year follow-up. In the subgroup analysis, there tended to be even faster resorption in the steroid group from baseline to 2 months for extrusions, and from 2 months to 12 months for contained herniations. No significant differences were observed in the enhancement parameters (coverage and thickness) between the two treatments.

CONCLUSIONS

Periradicular corticosteroid does not have a negative effect on the spontaneous resorption of the herniated nucleus pulposus.

Gadolinium diethylenetriaminepentaacetic acid enhancement in magnetic resonance imaging in relation to symptoms and signs among sciatic patients: a cross-sectional study

STUDY DESIGN

A cross-sectional descriptive study.

OBJECTIVES

Gadolinium enhancement in lumbar magnetic resonance imaging is not used routinely. The current study explored the possible intercorrelations of enhancement patterns with clinical symptoms and signs.

SUMMARY OF BACKGROUND DATA

Rim enhancement has been reported to occur in the periphery of disc herniations, and it is thought to represent neovascularization. To the authors' knowledge, the significance of the enhancement in relation to clinical symptoms has not been studied.

METHODS

Magnetic resonance imaging of the lumbar spine with intravenous gadolinium diethylenetriaminepentaacetic acid was performed in each patient. Various contrast enhancement parameters and volume of herniation were evaluated, and their correlations with clinical signs and symptoms (straight leg raising, motor defect, Achilles reflex, leg and back pain, disability) were analyzed.

RESULTS

The extent of rim enhancement correlated highly significantly with the degree of disc displacement, being most pronounced in the case of sequesters. The duration of sciatic symptoms correlated negatively with enhancement. The clinical symptoms did not correlate significantly with the different enhancement parameters or disc herniation volume. Straight leg raising correlated only slightly with the extent of rim enhancement (P = 0.04) when bulges were excluded. Achilles reflex abnormality correlated significantly with all enhancement parameters for lesions at L5-S1. In the final stepwise logistic regression model, contrast enhancement extent correlated most significantly with abnormal Achilles reflex (P = 0.0002).

CONCLUSIONS

Although rim enhancement of disc herniation is thought to represent a beneficial phagocytotic phenomenon, it may also have a harmful effect on the adjacent nerve root.