The Effect of Transcutaneous Electrical Nerve Stimulation of Sympathetic Ganglions and Acupuncture Points on Distal Blood Flow

Blood flow effects of percutaneous peripheral nerve stimulation. A blinded, randomized clinical trial

BACKGROUND

The vasculature function is mainly regulated by the autonomic nervous system. Importantly, the sensory-motor nervous system also innervates peripheral vessels and has the capacity to modulate vascular tone. Here we investigated the effects of electrical stimulation of a mixed nerve trunk on blood flow in deep arteries and muscle perfusion. Our hypothesis is that stimulation of a mixed nerve can modify blood flow.

METHODS

Twenty-nine healthy participants were included into a randomized-crossover and blinded clinical trial. Each subject received a placebo and two percutaneous peripheral nerve stimulation (pPNS) protocols on the median nerve: Pain Threshold continuous Low Frequency (PT-cLF) and Sensory Threshold burst High Frequency (ST-bHF). Blood flow was then assessed bilaterally using Power Doppler Ultrasonography at the main arteries of the arm, and blood perfusion at the forearm muscles. Afterwards, blood flow was quantified using a semi-automatized software, freely shared here.

RESULTS

Placebo, consisting in needle insertion, produced an immediate and generalized reduction on peak systolic velocity in all arteries. Although nerve stimulation produced mainly no effects, some significant differences were found: both protocols increased the relative perfusion area of the forearm muscles, the ST-bHF protocol prevented the reduction in peak systolic velocity and TAMEAN of the radial artery produced by the control protocol and PT-cLF produced a TAMEAN reduction of the ulnar artery.

CONCLUSIONS

Therefore, the arterial blood flow in the arm is mainly impervious to the electrical stimulation of the median nerve, composed by autonomic and sensory-motor axons, although it produces mild modifications in the forearm muscles perfusion.

Temporal effects of two interferential current applications on peripheral circulation in children with hemiplegic cerebral palsy

Objectives

To determine the short-term effects of sympathetic and peripheral stimulation of interferential current (IFC) on blood flow (BF) in children with hemiplegic cerebral palsy (CP).

Methods

Thirty children with hemiplegic CP, ranging from 8 to 12 years old, were randomly divided into three groups (10 children/group). The first group received sympathetic stimulation of IFC, the second group received peripheral stimulation of IFC, and the third group (control) received placebo peripheral stimulation of IFC. A frequency of 80–100 Hz at an intensity of 10–20 mA was applied for 20 min. Blood volume pulse (BVP) amplitude was measured before IFC application using a plethysmography sensor at the big toe immediately after and 15 min poststimulation. The data were statistically analyzed and compared.

Results

There were statistically significant differences in BVP amplitude among the three time intervals in both the sympathetic and peripheral groups (P < 0.05) with no difference in the control group (P = 0.995). There was a significant increase in BVP amplitude immediately after stimulation compared with before stimulation in both the sympathetic and peripheral groups (P = 0.0001). However, differences between the sympathetic and peripheral groups at the three measured periods were statistically nonsignificant (P > 0.05).

Conclusion

Both IFC applications had a proper effect on improving BF in children with hemiplegic CP with no difference in efficacy between sympathetic and peripheral stimulation.

Effects of Transcutaneous Electrical Nerve Stimulation on Proinflammatory Cytokines: Systematic Review and Meta-Analysis

The mechanism of pain reduction involves bidirectional processes of pain blocking (nociception) and reductions in the levels of proinflammatory cytokines in the blood. Does transcutaneous electrical nerve stimulation (TENS) reduce blood levels of proinflammatory cytokines? For this systematic review, we searched in six databases to identify randomized controlled trials with the criteria: humans older than 18 years (adults), use of TENS in the experimental group, and having at least one pre- and postintervention blood level of at least one proinflammatory cytokine. The risk of bias and the level of evidence were assessed. Five studies were included involving 240 participants. The heterogeneity of the studies was high (I²: 85%); therefore, we used a random-effects meta-analysis. It was observed through the meta-analysis synthesis measures that there were statistically significant differences following the use of TENS to reduce the general group of cytokines. When grouped by chronic disease, by postoperative settings, or by individual studies in the case of IL-6, it was observed that the significant reduction of cytokines related to the use of TENS was maintained. The use of TENS reduced the blood levels of proinflammatory cytokines (we observed a protective factor of TENS in relation to inflammation). The protocol of the systematic review was registered in PROSPERO, CRD42017060379.

Effects of transcutaneous electrical nerve stimulation (TENS) on proinflammatory cytokines: protocol for systematic review

BACKGROUND

Pain reduction can be achieved by lowering proinflammatory cytokine levels in the blood. Transcutaneous electrical nerve stimulation (TENS) is a non-invasive physiotherapeutic resource for pain management, but evidence on the effectiveness of this device at reducing proinflammatory cytokines in the blood is unclear. This study systematically reviews the literature on the effect of TENS on proinflammatory cytokines.

METHODS

A systematic review protocol was developed based on searches of articles in six electronic databases and references of retrieved articles, contact with authors, and repositories of clinical trials. Eligibility criteria: publication in peer-reviewed journals, randomized clinical trials, use of TENS in the experimental group, and pre- and post-measurements of proinflammatory cytokines in the blood. Selection of the studies and extraction of the data will be carried out by two reviewers independently. Characteristics of the study, participants, interventions and outcomes were extracted and described. Assessments were performed on the risk of bias, level of evidence and the size of the intervention effect in the studies, according to GRADE guidelines and the Cochrane Handbook for Systematic Reviews. Clinical and statistical assessments compared the effects of the interventions (meta-analysis), taking into consideration any influencing characteristics of the studies (e.g., methods and application sites).

DISCUSSION

We anticipate that this review will strengthen evidence-based knowledge of the effect of TENS on proinflammatory cytokines and, as a result, direct new studies to benefit patients with specific pathologies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42017060379 .