Antidromic sensory nerve conduction study of the digital branches of the medial plantar nerve: A novel method to detect early diabetic sensory axonal polyneuropathy.

Introduction. Distal sensory neuropathy is the most common form of diabetic neuropathy. We developed a novel antidromic technique for assessment of distal nerve function for early diagnosis of diabetic neuropathy. Methods. Diabetic and control groups underwent standard and more distal sensory nerve conduction studies (NCS); sensory nerve action potentials (SNAPs) of the proper digital branches of the medial plantar nerve were recorded with our method after stimulation at the sole and recording from digits I and II. Results. Comparison between controls and diabetics showed a statistically significant difference in mean SNAP amplitudes for all tested nerves. A higher percentage of abnormal SNAPs was obtained with our technique than with either conventional or more distal NCS in all patients. Discussion. As compared with clinical evaluation and other NCS, our antidromic stimulation was the most sensitive method to detect abnormal sensory nerve conduction in symptomatic and asymptomatic diabetic patients.