Qualitative grading of disc degeneration by magnetic resonance in the lumbar and cervical spine: lack of correlation with histology in surgical cases

Abstract

Background: Clinically, magnetic resonance (MR) imaging is the most effective non-invasive tool for assessing IVD degeneration. Histological examination of the IVD provides a more detailed assessment of the pathological changes at a tissue level. However, very few reports have studied the relationship between these techniques. Identifying a relationship may allow more detailed staging of IVD degeneration, of importance in targeting future regenerative therapies. Objectives: To investigate the relationship between MR and histological grading of IVD degeneration in the cervical and lumbar spine in patients undergoing discectomy. Methods: Lumbar (N = 99) and cervical (N = 106) IVD samples were obtained from adult patients undergoing discectomy surgery for symptomatic IVD herniation and graded to ascertain a histological grade of degeneration. The pre-operative MR images from these patients were graded for the degree of IVD (MR grade) and vertebral end-plate degeneration (Modic Changes, MC). The relationship between histological and MR grades of degeneration were studied. Results: In lumbar and cervical IVD the majority of samples (93%) exhibited moderate levels of degeneration (ie MR grades 3-4) on pre-operative MR scans. Histologically, most specimens displayed moderate to severe grades of degeneration in lumbar (99%) and cervical spine (93%). MR grade was weakly correlated with patient age in lumbar and cervical study groups. MR and histological grades of IVD degeneration did not correlate in lumbar or cervical study groups. MC were more common in the lumbar than cervical spine (e.g. 39 versus 20% grade 2 changes; p < 0.05), but failed to correlate with MR or histological grades for degeneration. Conclusions: In this surgical series, the resected IVD tissue displayed moderate to severe degeneration, but there is no correlation between MR and histological grades using a qualitative classification system. There remains a need for a quantitative, non-invasive, pre-clinical measure of IVD degeneration that correlates with histological changes seen in the IVD.

Keywords:

• Cervical
• histology
• intervertebral disc
• lumbar
• magnetic resonance imaging
• spine

Acknowledgements

We are grateful to Neurosurgical colleagues at Salford Royal NHS Foundation Trust, notably Messrs Ahmed Abou-Zeid, Ashok Bhat and Ahmed Suroor for assisting in patient recruitment. We acknowledge Mr Christian Cerra’s contribution to data collection as part of a preliminary study.

Disclosure statement

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in paper.

Funding information

This research was part funded by the Arthritis Research Campaign. FL is part funded by Depuy Spine. KG holds an Educational consultant contract with Depuy-Synthes Spine (Raynham, US). The Intervertebral Disc Research Group within the Centre for Regenerative Medicine, Institute of Inflammation and Repair is supported by the Manchester Academic Health Science Centre (MAHSC) and the NIHR Manchester Musculoskeletal Biomedical Research Unit. Tissue samples, magnetic resonance images and associated clinical data were obtained through the Spinal Intervertebral Disc Tissue Bank held at the University of Manchester, in collaboration with Salford Royal NHS Foundation Trust.