Diabetic neuropathy increases stimulation threshold during popliteal sciatic nerve block

Abstract

BackgroundPeripheral nerve stimulation is commonly used for nerve localization in regional anaesthesia, but recommended stimulation currents of 0.3–0.5 mA do not reliably produce motor activity in the absence of intraneural needle placement. As this may be particularly true in patients with diabetic neuropathy, we examined the stimulation threshold in patients with and without diabetes.MethodsPreoperative evaluation included a neurological exam and electroneurography. During ultrasound-guided popliteal sciatic nerve block, we measured the current required to produce motor activity for the tibial and common peroneal nerve in diabetic and non-diabetic patients. Proximity to the nerve was evaluated post-hoc using ultrasound imaging.ResultsAverage stimulation currents did not differ between diabetic (n=55) and non-diabetic patients (n=52). Although the planned number of patients was not reached, the power goal for the mean stimulation current was met. Subjects with diminished pressure perception showed increased thresholds for the common peroneal nerve (median 1.30 vs. 0.57 mA in subjects with normal perception, P=0.042), as did subjects with decreased pain sensation (1.60 vs. 0.50 mA in subjects with normal sensation, P=0.038). Slowed ulnar nerve conduction velocity predicted elevated mean stimulation current (r=−0.35, P=0.002). Finally, 15 diabetic patients required more than 0.5 mA to evoke a motor response, despite intraneural needle placement (n=4), or required currents ≥2 mA despite needle-nerve contact, vs three such patients (1 intraneural, 2 with ≥2 mA) among non-diabetic patients (P=0.003).ConclusionsThese findings suggest that stimulation thresholds of 0.3–0.5 mA may not reliably determine close needle-nerve contact during popliteal sciatic nerve block, particularly in patients with diabetic neuropathy.Clinical trial registrationNCT01488474

<p>Diabetic Peripheral Neuropathy Increases Electrical Stimulation Threshold of Sciatic Nerve: A Prospective Parallel Cohort Study</p>

“…30 Heschl reported the minimum current threshold showed a highly significant negative correlation with 4452 a conduction velocity of the peroneal and ulnar nerves, and a positive correlation with the latent period of the action potential of the tibial and ulnar nerves. 31 The correlation of the threshold with nerve conduction velocity was significant.…”

Uszkodzenie nerwu jako powikłanie znieczulenia nerwów obwodowych

“…The lack of motor response to an intensity of 2.4 mA was observed in many diabetic patients, despite explicit, ultrasound-confirmed needle-nerve contact [50]. There is a high individual variability in the threshold current intensity required to induce a motor response, while such extremely high intensities of the stimulation current, although more commonly observed in diabetic patients, with diabetic neuropathy, in particular, have also been found in healthy individuals [64].…”

Can We Agree What Skilled Mindfulness-Based Teaching Looks Like? Lessons From Studying the MBI:TAC

“…4 The MBI:TAC is being integrated into research protocols—both as a check on intervention integrity 5 and as a tool to examine MBP teacher training and teacher factors. 6 , 7 Another factor influencing uptake is that currently the MBI:TAC is the only tool that is anchored into the 2 main empirically supported MBPs (Mindfulness-Based Stress Reduction [MBSR] and MBCT) which assesses both adherence and competence.…”

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