ABSTRACT
Measurement of the evoked action potential in muscle as an adjunctive to the clinical evaluation of peripheral nerve lesion resulted in the more frequent use of compound muscle action potential to evaluate peripheral nerve problems. Recently, the intraoperative use of nerve stimulation and recording technique have made it possible to evaluate the peripheral nerve problems intraoperatively. The present study was, therefore, undertaken to address this question in rabbit sciatic nerves and to determine intraoperative stimulation and recording technique are practical in clinical situations. A low-heat injury to the sciatic nerve was induced by perfusing 60degrees C saline around the nerve for 30 minutes and followed the courses of functional and morphological recovery of the nerve for 16 weeks. The results are ,summarized as follows ; In the test of compound muscle action potential(CMAP), the average amplitude and the onset latency were markedly attenuated at 4 and 8 week after the low-heat treatment (1.2mV, 4.2mV)(3.58msec, 2.68msec)(p=0.045, p=0.039). It progressively reverted to tile control level, showing 0.63 msec at 16 weeks. In the test of intraoperative nerve action potential(INAP), the average amplitude and the onset latency were attenuated at 4 and 8 weeks after the low-heat treatment(1.8mV, 2.1 mV)(1.18msec, 1.05msec)(p=0.041, p=0.043). There existed a significant positive correlation between the amplitude and onset latencies of INAP and CMAP measured in Low-heat group(r=0.67, r=0.71, p=0.003, p=0.009). Similar pattern of amplitude and onset latency between tests of CMAP and INAP suggests that INAP was practical and useful.