Comparison of Ultrasound-Guided Percutaneous and Open Surgery Approaches in The Animal Model of Tumor Necrosis Factor-Alpha-Induced Disc Degeneration

Animal models provide a deeper understanding about various complications and better demonstrate the effect of therapeutic approaches. One of the issues in the low back pain (LBP) model is the invasiveness of the procedure and it does not mimic actual disease conditions in humans. The purpose of the present study was to compare the ultrasound-guided (US-guided) percutaneous approach with the open-surgery method in the tumor necrosis factor-alpha (TNF-α)-induced disc degeneration model for the first time to showcase the advantages of this recently developed, minimally invasive method.

In this experimental study, eight male rabbits were divided into two groups (open-surgery and US-guided). Relevant discs were punctured by two approaches and TNF-α was injected into them. Magnetic resonance imaging (MRI) was performed to assess the disc height index (DHI) at all stages. Also morphological changes (annulus fibrosus, nucleus pulposus) were evaluated by assessing Pfirrmann grade and histological evaluation (Hematoxylin & Eosin).

The findings indicated targeted discs became degenerated after six weeks. DHI in both groups was significantly reduced (P<0.0001), however the difference was not significant between the two groups. In the open-surgery group, osteophyte formation was seen at six and eighteen weeks after the puncture. Pfirrmann grading revealed significant differences between injured and adjacent uninjured discs (P<0.0001). The US-guided method indicated significantly fewer signs of degeneration after six (P=0.0110) and eighteen (P=0.0328) weeks. Histological scoring showed significantly lower degeneration in the US-guided group (P=0.0039).

The US-guided method developed a milder grade condition and such a model better mimics the chronic characteristics of LBP and the procedure is more ethically accepted. Therefore, the US-guided method could be a merit approach for future research in this domain as a safe, practical and low-cost method.