THE EFFECT OF AMMONIUM-SULFATE INJECTION ON PERIPHERAL-NERVE

Local anesthetic drugs with prolonged nerve-block effect would have cl inical application for postoperative or neuromatous pain relief. This study evaluated the possibility of peripheral nerve neurotoxicity by i njection of 10 percent ammonium sulfate. Both intrafascicular and extr afascicular injection of 10 percent ammonium sulfate were tested in th e rat sciatic nerve model. One percent lidocaine HCl, 5 percent phenol , and normal saline were similarly injected for comparison. Using hist ologic studies and motor function evaluation with walking-track anaiys is, 10 percent ammonium sulfate was found to be neurotoxic when it is injected intrafascicularly; however, extrafascicuiar injection of this drug did not cause significant nerve injury. The neurotoxicity of the 10 percent ammonium sulfate solution was intermediate between the neu rotoxicity of 0.1 percent lidocaine hydrochloride and the marked neuro toxicity of 5 percent phenol solution.