The segmental conduction study on sural nerve would reveal progression of diabetic neuropathy

초록

Objective: The pathophysiology of diabetic metabolic neuropathy has a length dependent pattern. But in pathology some proximal axons showed demyelination lesion and distal part showed axonal degeneration. So we devised multi-segmental conduction study(NCS) to find progression of predominant pathophysiologic pattern (demyelinating or axonal injury) to select proper therapeutic measures. Patients and methods: We recruited 15 diabetic patients (30 sural nerves,male=9, 52.6 ±11.5 yrs) with some sensory symptoms and 12 normal controls (24 sural nerves, male=10, 46.4 ±13.3 yrs). Standard NCS on motor, sensory nerves in upper (median, ulnar nerves) and lower extremity (peroneal, sural, and tibial nerves) were done. Diabetics were classified into two groups (with or without polyneuropathy). Orthodromic sural segmental NCS was done; belowlateral malleolus 7 cm, above malleolus 7 cm, and next 7 cm to calf (total 21 cm). Results: 1. There is no difference between diabetic patients and control in age (p N 0.05). But, older subjects were more susceptible for diabetic neuropathy, but relevance was insignificant (p N 0.05). 2. There is significant difference of amplitudes in all three segments (esp, segment 2; 16.9 ±8.4 μV, 12.9 ± 11.2, 4.5 ±3.3, r=−0.533, p b 0.05). 3. Conduction velocity of diabetic neuropathy patients are affected in first segment (32.6 ± 3.8 m/s, 39.2 ± 3.5, 27.5 ± 9.3, r=−0.299, p b 0.05). In second, third segment, between three groups, results were not significant. Conclusion: 1. In this NCS reconfirmed that diabetic neuropathy shows length dependent pattern neuropathy known as before. 2. If we use segmental NCS in sural nerve, we would obtain more relevant information for understanding pathophysiology of diabetic neuropathy.