Prevalence of Upper and Lower Extremity Tinel Signs in Diabetics: Crosssectional Study from a United States, Urban Hospital-based Population

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Objective: To evaluate the prevalence of the Tinel Sign in the upper and lower extremities of patients with diabetes in an urban community. Methods: An IRB-approved, prospective, cross-sectional, descriptive study was performed on patients with diabetes during their visit to the endocrinologist. Eighty-one consecutive patients (162 sides) were examined by a fellowship-trained Hand Surgeon, experienced in performing the “Tinel Sign”. Mean duration of diabetes was 18.5 years. In the upper extremity known sites of anatomic entrapment were percussed; median nerve at the wrist (carpal tunnel), ulnar nerve at the elbow (cubital tunnel), radial sensory nerve in the forearm, and a negative control site. In the lower extremity, sites were tibial nerve at ankle (tarsal tunnel), proximal tibial nerve (soleal sling), common peroneal nerve at fibular neck (fibular tunnel), superficial peroneal nerve, deep peroneal nerve over dorsum of the foot, and a negative control site. Neuropathy was defined as a score greater than 4 on the Michigan Neuropathy Screening Instrument (MNSI). Statistical evaluation included linear regression, analysis of variance, and Tukey’s post hoc test. Results: 100% of the control sites had absent Tinel Sign. MNSI score and number of positive Tinel Signs were highly correlated ( r=0.94, p=0.001). Upper extremity, prevalence of Tinel Sign in patients with neuropathy (i.e. MNSI >4) ranged from 46.2% to 65% compared to 2.4% to 19.5% without neuropathy (MNSI < 4). Lower extremity prevalence ranges were 23% to 59% with neuropathy and 0% to 17.1% without neuropathy. The chances of having a positive Tinel Sign in the contralateral limb were 38.2%, 42.2%, 44.7% and 48.4% for carpal tunnel, cubital tunnel, fibular tunnel and tarsal tunnel, respectively. Conclusion: Presence of a Tinel sign was highly correlated with presence of neuropathy in diabetics.