Does intradiscal steroid injection accelerate the histological degeneration of the human disc?

Abstract

Objectives: Intradiscal steroid injection (ISI) use has been proven as a low-risk and rapid treatment for disc degeneration disease (DDD). However, the histological effects of steroids on human discs remain poorly understood. The purpose of this study is to investigate whether ISI induces histologic degeneration of the disc.

Methods: In this study, a histological analysis was carried out on the nucleus pulposus obtained from 150 patients who underwent posterior lumbar interbody fusion. Among these individuals, 59 received ISI before the surgery, while 91 did not. After staining with hematoxylin and eosin, the histological classification was performed based on chondrocyte proliferation (C1, C2, and C3) and granular matrix change (M1 and M2). Logistic regression analysis was used to identify the main factors influencing chondrocyte proliferation and granular matrix change. Additionally, histological differences between the ISI group and the non-ISI group were analyzed.

Results: Chondrocyte proliferation and granular matrix changes were not significantly different between the ISI and non-ISI groups. The logistic regression analysis indicated that age is the most significant risk factor for both chondrocyte proliferation (P = 0.02) and granular matrix changes (P < 0.01).

Conclusions: The most crucial factor in disc degeneration is age. ISI does not accelerate the histological degeneration of chondrocyte proliferation and granular matrix. Therefore, the ISI could be considered as a histologically safe alternative in patients with DDD.

Keywords: Histology; Intervertebral disc degeneration; Intradiscal injection; Steroids.

Fig. 1

Patient selection process. L, lumbar; PLIF, posterior lumbar interbody fusion; ISI, intradiscal steroid injection; MRI, magnetic resonance imaging.

Fig. 2

A representative case of a patient treated with intradiscal steroid injection. A: Preoperative magnetic resonance imaging of a patient with L4-5 disc degeneration. B: The C-arm image after dye injection showed that the dye leaked out from the annulus fibrosus and spread to the anterior aspect of the dura (dotted).

Fig. 3

Histologic classification for the chondrocyte proliferation. (Hematoxylin and eosin, ×200, original magnification). A: Grade 1. Single round chondrocyte (arrow) and two connected chondrocytes (arrowhead). B: Grade 2. Clusterization of four chondrocytes (arrow), surrounded by a pericellular matrix (star). C: Grade 3. Numerous chondrocytes grouped together (arrow).

Fig. 4

Histologic classification for the matrix granular change. (Hematoxylin and eosin, ×200, original magnification). A: Grade 1. Structurally well-organized fibrocartilage in uniform arrangement (arrowhead) and single chondrocyte (arrow). The matrix granular change is under 5% of matrix. B: Grade 2. Eosinophilic-staining amorphous granules in fibrocartilage (star).