Morphological changes in disc herniation in the lower cervical spine: an ultrastructural study

Introduction

The basis of disc degeneration is still unknown, but is believed to be a cell-mediated process. Apoptosis might play a major role in degenerative disc disease (DDD). The aim of this study was to correlate the viability of disc cells with the radiological degeneration grades (rDG) in disc herniation.

Materials and methods

Forty anterior IVD’s (C4–C7) from 39 patients with DDD were studied histologically and ultrastructurally to quantify healthy, “balloon”, chondroptotic, apoptotic and necrotic cells. Patients were classified to their rDG, as having either prolapse (P: DGII + III) and/or osteochondrosis (O: DGIV + V). Similar studies were undertaken on eight control discs.

Results

Cell death by necrosis (mean 35%) was common but differed not significantly in both groups. All patients with a disc prolapse DGII + III revealed balloon cells (iAF: mean 32%). All appeared alive and sometimes were hypertrophic. However, significantly less balloon cells were found in the O-Group. Control samples revealed no evidence of “balloon” cells in DGII and only a minor rate in DGIII.

Conclusion

According to the different rDG, quantitative changes were obvious in healthy and “balloon” cells, but not for cell death. At the moment it can only be hypothesized if “balloon” cells are part of a repair strategy and/or cause of disc herniation.