Effect of Artificial Degeneration Induced by Needle Puncture on Time-Dependent Response of Intervertebral Disc

Understanding the mechanism of artificial disc degeneration using animal models is useful to study the regenerative techniques in hope of finding potential therapeutic strategies. For any type of potential therapeutic techniques, first we need to have the degenerated model. Disc degeneration can be mimicked in animal studies using needle puncture. However, the detailed mechanical response of the artificial degenerated disc using needle puncture under physiological diurnal activities has not been analyzed well. Hence, reverse finite element analyses combined with in-vitro experiments were used in this study to find the mechanical properties of intact (N=8) and injured discs using needle puncture (N=8). Afterward, specimen-specific FE models for 16 discs were simulated during physiological diurnal activity. The results showed that the variation of axial displacement, intradiscal pressure, and total fluid exchange in intact discs were significantly higher than the injured ones after 24h. But the maximum axial stress within disc was significantly higher in injured group. The achieved results are correlated with previous human cadaver data for natural disc degeneration. Therefore, it is concluded that the G-16 needle puncture injury is a simple and cost-effective methodology which can be used to mimic the degeneration mechanism in animal models.