A Novel Extreme Lateral Approach for Needle Puncture Model of Lumbar Disc Degeneration in SD Rats.

Abstract Background: Various animal models have been proposed to investigate several aspects of intervertebral disc degeneration (IDD). As for needle puncture model, literatures have mentioned the needle puncture in percutaneous posterolateral approach, anterior ventral approach. Our research is mean to describe a novel, extreme lateral invasive approach without posterior paraspinal muscle for needle puncture rat model.Methods: 16 adult female SD rats aging 12 weeks old was used to perform this research, which was randomly divided into two groups. We used the extreme lateral approach from the skin to lumbar intervertebral disc and advancing the 18G needle into the intervertebral disc in the experimental group and without needle puncture in the control group. Disc degeneration was confirmed by magnetic resonance imaging (MRI)and histologic evaluation.Results: All rats survived the duration of the experiment. 60 days after operation, the puncture discs of experimental group showed a significant decrease of signal intensity in the T2-weighed magnetic resonance imaging comparing with the control discs of control group. Histological analysis demonstrated the boundary between the nucleus pulposus (NP) and annulus fibrosus (AF) was not distinct, even the connective tissue nearly replaced the position of NP and proteoglycan content decreased within the punctured discs compared to the control discs. Histological score showed statistical significant difference between injury discs and control discs.Conclusions: Our study demonstrated a novel, reliable and safe approach for the needle puncture model of lumbar disc degeneration in SD rats, which provides a potential experimental model for the research on IDD without posterior paraspinal muscle injury.