Histological Changes after Intradiscal Steroid Injection to the Intervertebral Disc in Disc Injury Rabbit Model

ABSTRACT

OBJECTIVE: To evaluate the degeneration changes of disc injury rabbit model produced by needle puncture to intervertebral disc and to observe the histological changes of the degenerated disc treated with intradiscal steroid. METHOD: The subjects were composed of 10 L4-5 intervertebral discs (study group) and 10 L3-4 intervertebral discs (control group) of Newzealand white rabbits. The rabbits' discs were exposed by anterior approach and degeneration was elicited by 21 G needle puncture. After 4 weeks, the study group was injected with 0.2 ml triamcinolone acetonide (Tamcetone 40 mg/ml) and the control group was injected with 0.2 ml normal saline, intradiscally. The discs were extracted on 4 weeks after degeneration and stained with Hematoxylin-Eosin and investigated by light microscopy. RESULTS: Degenerative changes, including fissuring and focal fibrosis, were elicited in the all groups, but there were no significant histological differences between the two groups. CONCLUSION: We concluded that the degenerative changes are well observed in disc injury rabbit model. The mollification of discogenic pain following intradiscal steroid injection in practice may not be explained from light microscopic histological changes of the disc. Further biochemical or electromicroscopic study will be necessary to clarify the mechanism of alleviation of discogenic pain by intradiscal steroid.