Supervisors info:
Ζαμπέλης Θωμάς, Ομότιμος Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Καρανδρέας Νικόλαος, Ομότιμος Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Κοκότης Παναγιώτης, Αναπληρωτής Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Summary:
Introduction: Nerve conduction studies of sural and dorsal sural nerve are a sensitive method of early detection of peripheral symmetric length-depedent polyneuropathy. Diabetes mellitus is the most common cause of peripheral polyneuropathy worldwide. The objective of this study is to contribute to the early diagnosis of typical diabetic polyneuropathy through the sural/dorsal sural SNAP amplitude ratio, when the established clinical and neurophysiological criteria are not yet met.
Methods and materials: a case control comperative neurophysiological study was conducted. The sural and dorsal sural SNAP amplitude and their ratio, as well as the sensory conduction velocity (SCV), were compared in 25 healthy controls and 25 diabetic patients, who had not the essential clinical and neurophysiological findings of typical diabetic polyneuropathy. The statistical program GraphPad Prism 9.3.0 was used for statistical analysis of data.
Results: in healthy controls, the mean sural SNAP amplitude and SCV were 17.3±5.73μV (range 11.1-38.8μV) and 48.2±2.65m/s (range 42.9-52.8m/s) respectively, the mean dorsal sural SNAP amplitude and SCV were 7.64±3.30μV (range 3.8-20.2μV) and 40.4±2.84m/s (range 34.7-46.7m/s) respectively, the mean sural/dorsal sural SNAP amplitude ratio was 2.39±0.54 (range 1.58-3.51). In diabetic patients, the mean sural SNAP amplitude and SCV were 14.3±3.66μV (range 10.2-26.3μV) and 47.1±2.64m/s (range 41-51,7m/s) respectively, the mean dorsal sural SNAP amplitude and SCV were 5.9±2.25μV (range 1.7-10.5μV) and 38.8±4.02m/s (range 28.7-47.4m/s) respectively, the mean sural/dorsal sural SNAP amplitude ratio was 2.76±1.23 (range 1.30-6.18). There was statistically significant decrease in mean sural SNAP amplitude (p=0.0109) and mean dorsal sural SNAP amplitude (p=0.0263) in diabetic patients , but not in mean sural/dorsal sural SNAP amplitude ratio and mean SCV of the two nerves. 20% of diabetic patients had sural/dorsal sural SNAP amplitude ratio > 3,51, which was the maximum value in healthy controls.
Conclusion: It has not been proved directly the utility of sural/dorsal sural SNAP amplitude ratio in early diagnosis of typical diabetic polyneuropathy. Nevertheless, it has been shown that in diabetic patients the pathological process may have already affected the sural nerve, not only in the distal part, the dorsal sural nerve, but also more proximal, before any typical clinical or electrophysiological criteria of polyneuropathy are met. Moreover, sural/dorsal sural SNAP amplitude ratio > 3,51, may be a neurophysiological sign of early diagnosis of typical diabetic polyneuropathy. In conclusion, nerve conduction study of both sural and dorsal sural nerve and calculation of sural/dorsal sural SNAP amplitude ratio seem to be worth in early stage of diabetes.
Keywords:
Dorsal sural nerve, Sural nerve, Sural/dorsal sural SNAP amplitude ratio, Diabetic polyneuropathy, Early diagnosis
