A Study of the Safety of Low Temperature Plasma Radiofrequency Ablation on Rat Sciatic Nerve.

Purpose: Low temperature plasma radiofrequency ablation (LTPRA) has been widely applied for widespread clinical use in a variety of disciplines. However, the safe distance to act in the vicinity of neural tissue has not been determined. Methods: Adult male Sprague-Dawley rats were subjected to LTPRA surgery performed at 0mm, 1mm and 2mm from the sciatic nerve or by cutting only the skin muscle to expose the sciatic nerve. Paw withdrawal thresholds (PWT) were determined at different time points, neurophysiology was examined, and the sciatic nerve was harvested for light and electron microscopic evaluation and Elisa for expression of proinflammatory cytokines and pain-related markers. Results: At 14 days postoperatively, both the 0mm and 1mm groups showed a decrease in PWT, a reduction in the peak amplitude of compound muscle action potentials (CMAPs), a decline in the number of Schwann cells, the area of myelin sheaths, and thinner myelin thickness, additionally, both groups exhibited upregulation of TNF-α, IL-1β, NGF, and C-fos in the sciatic nerve; furthermore, the 0mm group also exhibited slowed nerve conduction velocity, prolonged latency, and myelin vacuolization. The 2mm group exhibited transient reductions in PWT and elevated IL-1β and C-fos at 14 days, and all of these indicators fully recovered on postoperative day 28. Conclusion: LTPRA causes only temporary and reversible changes 2 mm away from the sciatic nerve in rats, which can be recovered within 28 days. This study identifies a 2mm safety threshold for LTPRA to mitigate neurological sequelae, informing surgical guidelines.