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Updated: Jul 7, 2026
A Proinflammatory, Degenerative Organ Culture Model to Simulate Early-Stage Intervertebral Disc Disease.
Published on: February 14, 2021
Lumbar disc extrusions reduce faster than bulging discs due to an active role of macrophages in sciatica
N Djuric1, X Yang2, A El Barzouhi2
1Department of Neurosurgery, Leiden University Medical Center, Albinusdreef 2, 2300 RC, Leiden, Netherlands. n.djuric@lumc.nl.
Objective:
This retrospective observational histological study aims to associate the size and type of disc herniation with the degree of macrophage infiltration in disc material retrieved during disc surgery in patients with sciatica.
Methods:
Disc tissue of 119 sciatica patients was embedded in paraffin and stained with hematoxylin and CD68. Tissue samples were categorized as mild (0-10/cm2), moderate (10-100/cm2), and considerable (> 100/cm2) macrophage infiltration. All 119 patients received an MRI at baseline, and 108 received a follow-up MRI at 1-year. MRIs were reviewed for the size and type of the disc herniations, and for Modic changes in the vertebral endplates.
Results:
Baseline characteristics and duration of symptoms before surgery were comparable in all macrophage infiltration groups. The degree of macrophage infiltration was not associated with herniation size at baseline, but significantly associated with reduction of size of the herniated disc at 1-year post surgery. Moreover, the degree of macrophage infiltration was higher in extrusion in comparison with bulging (protrusion) of the disc. Results were comparable in patients with and without Modic changes.
Conclusion:
Macrophage infiltration was positively associated with an extruded type of disc herniation as well as the extent of reduction of the herniated disc during 1-year follow-up in patients with sciatica. This is an indication that the macrophages play an active role in reducing herniated discs. An extruded disc herniation has a larger surface for the macrophages to adhere to, which leads to more size reduction.
Insights
Macrophage infiltration in herniated discs is linked to extrusion and aids in size reduction over one year. This suggests macrophages actively help shrink extruded disc herniations in sciatica patients.
Area of Science:
- Spinal Surgery
- Histopathology
- Immunology
Background:
- Sciatica is often caused by herniated discs.
- Macrophage infiltration is a key immune response in tissue healing and remodeling.
Purpose of the Study:
- To investigate the association between macrophage infiltration and disc herniation characteristics.
- To determine if macrophage infiltration correlates with herniation size reduction post-surgery.
Main Methods:
- Histological analysis of disc tissue from 119 sciatica patients using CD68 staining for macrophages.
- MRI assessment of herniation size and type at baseline and 1-year follow-up.
- Categorization of macrophage infiltration into mild, moderate, and considerable levels.
Main Results:
- Macrophage infiltration was higher in extruded herniations compared to bulging types.
- No association was found between baseline infiltration and herniation size.
- Significant association between higher macrophage infiltration and greater herniation size reduction at 1-year follow-up.
Conclusions:
- Macrophage infiltration plays a role in the resolution of herniated discs, particularly extruded types.
- The increased surface area of extruded herniations may facilitate macrophage adherence and subsequent size reduction.
- Findings suggest a potential therapeutic target for managing sciatica.
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