Transcutaneous electrical nerve stimulation (TENS) as an adjunct for pain management in perioperative settings: a critical review

Exploration of treatment strategies and susceptibility gene of postoperative nausea and vomiting in breast cancer patients: a randomised controlled trial

BACKGROUND

A history of severe nausea and vomiting during pregnancy (SNVP) is a risk factor for postoperative nausea and vomiting (PONV). This study aimed to explore potentially effective treatment strategies and potential genetic factors underlying SNVP risk-related PONV.

METHODS

A total of 140 female patients undergoing breast cancer surgery were assigned to either the study group (70 with SNVP) or the control group (70 with mild to moderate nausea and vomiting during pregnancy (MNVP)). Patients in each group were randomly assigned to two different treatment subgroups and received either ondansetron plus dexamethasone (OD) or OD + TEAS (ODT) (transcutaneous electrical acupoint stimulation, TEAS). Blood samples were collected from patients before induction (D0) and 24 h (D1) after surgery for growth differentiation factor 15 (GDF-15) evaluation. The primary outcome was the incidence of PONV within 36 h. The secondary outcome was the serum GDF-15 level.

RESULTS

The incidence of PONV in the SNVP group was significantly higher than that in the MNVP group within 24 h (P < 0.005). In the SNVP group, ODT-treated patients had less PONV than those in the OD-treated group during the 6-12 h (P = 0.033) and 12-24 h (P = 0.008) intervals, while within 6 h, there were fewer vomiting cases in the ODT-treated group (SNVP-ODT vs. SNVP-OD, 7/33 vs. 19/35, P = 0.005). The preoperative GDF-15 serum levels in patients with SNVP were significantly higher (P = 0.004). Moreover, higher preoperative GDF-15 serum levels correlated with a higher incidence of PONV (P = 0.043).

CONCLUSIONS

TEAS showed significant effect on PONV treatment in patients with SNVP. A higher serum GDF-15 level was associated with a history of SNVP, as well as a higher risk of PONV.

Comparative Neurological and Behavioral Assessment of Central and Peripheral Stimulation Technologies for Induced Pain and Cognitive Tasks

Pain is a multifaceted, multisystem disorder that adversely affects neuro-psychological processes. This study compares the effectiveness of central stimulation (transcranial direct current stimulation-tDCS over F3/F4) and peripheral stimulation (transcutaneous electrical nerve stimulation-TENS over the median nerve) in pain inhibition during a cognitive task in healthy volunteers and to observe potential neuro-cognitive improvements. Eighty healthy participants underwent a comprehensive experimental protocol, including cognitive assessments, the Cold Pressor Test (CPT) for pain induction, and tDCS/TENS administration. EEG recordings were conducted pre- and post-intervention across all conditions. The protocol for this study was categorized into four groups: G1 (control), G2 (TENS), G3 (anodal-tDCS), and G4 (cathodal-tDCS). Paired t-tests (p < 0.05) were conducted to compare Pre-Stage, Post-Stage, and neuromodulation conditions, with t-values providing insights into effect magnitudes. The result showed a reduction in pain intensity with TENS (p = 0.002, t-value = -5.34) and cathodal-tDCS (p = 0.023, t-value = -5.08) and increased pain tolerance with TENS (p = 0.009, t-value = 4.98) and cathodal-tDCS (p = 0.001, t-value = 5.78). Anodal-tDCS (p = 0.041, t-value = 4.86) improved cognitive performance. The EEG analysis revealed distinct neural oscillatory patterns across the groups. Specifically, G2 and G4 showed delta-power reductions, while G3 observed an increase. Moreover, G2 exhibited increased theta-power in the occipital region during CPT and Post-Stages. In the alpha-band, G2, G3, and G4 had reductions Post-Stage, while G1 and G3 increased. Additionally, beta-power increased in the frontal region for G2 and G3, contrasting with a reduction in G4. Furthermore, gamma-power globally increased during CPT1, with G1, G2, and G3 showing reductions Post-Stage, while G4 displayed a global decrease. The findings confirm the efficacy of TENS and tDCS as possible non-drug therapeutic alternatives for cognition with alleviation from pain.

Noninvasive Bioelectronic Treatment of Postcesarean Pain: A Randomized Clinical Trial

Importance

Improved strategies are needed to decrease opioid use after cesarean delivery but still adequately control postoperative pain. Although transcutaneous electrical stimulation devices have proven effective for pain control after other surgical procedures, they have not been tested as part of a multimodal analgesic protocol after cesarean delivery, the most common surgical procedure in the United States.

Objective

To determine whether treatment with a noninvasive high-frequency electrical stimulation device decreases opioid use and pain after cesarean delivery.

Design, Setting, and Participants

This triple-blind, sham-controlled randomized clinical trial was conducted from April 18, 2022, to January 31, 2023, in the labor and delivery unit at a single tertiary academic medical center in Ohio. Individuals were eligible for the study if they had a singleton or twin gestation and underwent a cesarean delivery. Of 267 people eligible for the study, 134 (50%) were included.

Intervention

Participants were randomly assigned in a 1:1 ratio to a high-frequency (20 000 Hz) electrical stimulation device group or to an identical-appearing sham device group and received 3 applications at the incision site in the first 20 to 30 hours postoperatively.

Main Outcomes and Measures

The primary outcome was inpatient postoperative opioid use, measured in morphine milligram equivalents (MME). Secondary outcomes included pain scores, measured with the Brief Pain Inventory questionnaire (scale, 0-10, with 0 representing no pain), MME prescribed at discharge, and receipt of additional opioid prescriptions in the postpartum period. Normally distributed data were assessed using t tests; otherwise via Mann-Whitney or χ2 tests as appropriate. Analyses were completed following intention-to-treat principles.

Results

Of 134 postpartum individuals who underwent a cesarean delivery (mean [SD] age, 30.5 [4.6] years; mean [SD] gestational age at delivery, 38 weeks 6 days [8 days]), 67 were randomly assigned to the functional device group and 67 to the sham device group. Most were multiparous, had prepregnancy body mass index (calculated as weight in kilograms divided by height in meters squared) higher than 30, were privately insured, and received spinal anesthesia. One participant in the sham device group withdrew consent prior to treatment. Individuals assigned to the functional device used significantly less opioid medication prior to discharge (median [IQR], 19.75 [0-52.50] MME) than patients in the sham device group (median [IQR], 37.50 [7.50-67.50] MME; P = .046) and reported similar rates of moderate to severe pain (85% vs 91%; relative risk [RR], 0.77 [95% CI, 0.55-1.29]; P = .43) and mean pain scores (3.59 [95% CI, 3.21-3.98] vs 4.46 [95% CI, 4.01-4.92]; P = .004). Participants in the functional device group were prescribed fewer MME at discharge (median [IQR], 82.50 [0-90.00] MME vs 90.00 [75.00-90.00] MME; P < .001). They were also more likely to be discharged without an opioid prescription (25% vs 10%; RR, 1.58 [95% CI, 1.08-2.13]; P = .03) compared with the sham device group. No treatment-related adverse events occurred in either group.

Conclusions and Relevance

In this randomized clinical trial of postoperative patients following cesarean delivery, use of a high-frequency electrical stimulation device as part of a multimodal analgesia protocol decreased opioid use in the immediate postoperative period and opioids prescribed at discharge. These findings suggest that the use of this device may be a helpful adjunct to decrease opioid use without compromising pain control after cesarean delivery.

The dose-dependent effects of transcutaneous electrical nerve stimulation for pain relief in individuals with fibromyalgia: a systematic review and meta-analysis

ABSTRACT

Transcutaneous electrical nerve stimulation (TENS) is a nonpharmacological modality widely used to manage pain; however, its effectiveness for individuals with fibromyalgia (FM) has been questioned. In previous studies and systematic reviews, variables related to dose of TENS application have not been considered. The objectives of this meta-analysis were (1) to determine the effect of TENS on pain in individuals with FM and (2) determine the dose-dependent effect of TENS dose parameters on pain relief in individuals with FM. We searched the PubMed, PEDro, Cochrane, and EMBASE databases for relevant manuscripts. Data were extracted from 11 of the 1575 studies. The quality of the studies was assessed using the PEDro scale and RoB-2 assessment. This meta-analysis was performed using a random-effects model that, when not considering the TENS dosage applied, showed that the treatment had no overall effect on pain (d+ = 0.51, P > 0.050, k = 14). However, the moderator analyses, which were performed assuming a mixed-effect model, revealed that 3 of the categorical variables were significantly associated with effect sizes: the number of sessions (P = 0.005), the frequency (P = 0.014), and the intensity (P = 0.047). The electrode placement was not significantly associated with any effect sizes. Thus, there is evidence that TENS can effectively reduce pain in individuals with FM when applied at high or at mixed frequencies, a high intensity, or in long-term interventions involving 10 or more sessions. This review protocol was registered at PROSPERO (CRD42021252113).

Complementary therapy for endometriosis related pelvic pain

In the setting of a global pandemic, it is vastly important now more than ever that patients have agency and control over pain management when living with a debilitating chronic pain disease such as endometriosis. We present a review of the available literature on the most popular and easily accessible complementary pain management therapies for endometriosis including Transcutaneous Electrical Nerve stimulator (TENS) units, diets, Cannabidiol (CBD), turmeric, meditation, yoga, and acupuncture. These are worthwhile recommendations; however, the data for each is limited and more research is needed to further support each of its use.

Home-Based Electrical Stimulation to Accelerate Wound Healing-A Double-Blinded Randomized Control Trial

BACKGROUND

Electrical stimulation (E-Stim) may offer a unique adjunctive treatment to heal complicated diabetic foot ulcers (DFU). Our primary goal is to examine the effectiveness of daily home-based E-Stim therapy to speed-up wound healing.

METHODS

Patients with chronic DFUs and mild to severe peripheral arterial disease (PAD) were recruited and randomized to either control (CG) or intervention (IG) groups. The IG received 1-hour home-based E-Stim therapy on daily basis for 4 weeks (4W). E-Stim was delivered through electrical pads placed above the ankle joint using a bio-electric stimulation technology (BEST^®) platform (Tennant Biomodulator^® PRO). The CG was provided with an identical but non-functional device for the same period. The primary outcome included wound area reduction at 4W from baseline (BL).

RESULTS

Thirty-eight patients were recruited and 5 were removed due to non-compliance or infection, leaving 33 participants (IG, n = 16; CG, n =17). At 4W, the IG showed a significant wound area reduction of 22% (BL: 7.4 ± 8.5 cm² vs 4W: 5.8 ± 8.0 cm², P = 0.002). Average of wound area was unchanged in the CG (P = 0.982). The self-report adherence to daily home-therapy was 93.9%.

CONCLUSIONS

Daily home-based E-Stim provides early results on the feasibility, acceptability, and effectiveness of E-Stim as an adjunctive therapy to speed up wound healings in patients with chronic DFU and mild to severe PAD.

Transcutaneous electrical nerve stimulation for pain during propofol injection: a randomized clinical trial

Background

Propofol is a short-acting intravenous sedative widely used for procedural sedation and general anesthesia. However, pain during propofol injection is a distressing adverse effect. This study was designed to investigate whether transcutaneous electrical nerve stimulation (TENS) could reduce pain during propofol injection compared to sham TENS.

Methods

In a randomized controlled trial, 80 patients were allocated to two groups: the active TENS group received electrical stimulation via two electrodes on the venous cannulation site, whereas the sham TENS group received no stimulus. After 20 min following TENS, propofol 0.5 mg/kg pain was injected intravenously and pain was evaluated using a four-point score (0 = none, 1 = mild, 2 = moderate, 3 = severe). Adverse effects associated with TENS were also recorded.

Results

The overall incidence of pain during propofol injection was 47.5% in the TENS group and 87.5% in the sham group (P < 0.001). The incidence of moderate pain was significantly lower in the TENS group (7.5%) than in the sham TENS group (42.5%) (P < 0.001). There were no complications associated with TENS.

Conclusion

Pre-treatment with TENS significantly reduced the incidence and intensity of pain during propofol injection.

Eliciting blinks by transcutaneous electric nerve stimulation improves tear fluid in healthy video display terminal users: A self-controlled study

We aimed to elicit strong blinks among healthy video display terminal (VDT) users by periorbital transcutaneous electric nerve stimulation (TENS) and evaluate its impact on the tear fluid and visual task. Appropriate TENS conditions were evaluated to evoke strong blinks under minimum discomfort. Seventeen healthy VDT users with noninvasive Keratograph first breakup time (NIKf-BUT) 5-15 s and Ocular Surface Disease Index (OSDI) scores < 15 were recruited in this study. Before the trial, noninvasive Keratograph average breakup time (NIKa-BUT), tear meniscus height (TMH) and OSDI scores were evaluated. Before each TENS session, the volunteers played Tetris while the corresponding blink rate and Tetris scores were recorded. Then, the participants underwent 30 minutes of TENS, which evoked blinking of their right eye 20 times per minute. Tetris scores were evaluated again during TENS. The Tetris scores and corresponding blink rate were assessed after each TENS session while NIKa-BUT, TMH and OSDI scores were recorded after the third and sixth TENS sessions. We found that OSDI scores declined significantly after the sixth TENS (P = .003). The NIKa-BUT of the right eye was promoted after the sixth TENS (P = .02), and the TMH was higher after the third and sixth TENS in both eyes (P = .03, P = .03 for right eyes respectively, P = .01, P = .01 for left eyes respectively). There was no significant difference between the adjusted Tetris scores before and during TENS (P = .12). The blink rate before and after TENS were unaffected after 6 sessions (P = .61). The results indicated that periorbital TENS effectively ameliorated ocular irritation and improved tear secretion and tear film stability by eliciting strong blinks in healthy VDT users without disturbing the visual task.

Role of Transcutaneous Electric Nerve Stimulation in Pain and Pulmonary Function in Patients after Bariatric Surgery

Background

Changes in lifestyle, a carbohydrate-rich diet, and decreased physical activity are part of the context that led to an obesity pandemic. Treating obesity is a task that requires multidisciplinary care; however, in many cases, conventional therapy has no effect, requiring surgical intervention. This, in turn, is not without risks and causes important changes in lung function. Therefore, the aim of this study is to evaluate the effect of electroanalgesia through conventional transcutaneous electrical nerve stimulation (TENS) on the pain and lung function in the postoperative period of bariatric surgery.

Methods

This is a controlled and blinded clinical trial with 66 subjects who underwent bariatric surgery. The participants were randomized into 2 groups as follows: an intervention group treated with TENS (n = 33) and a placebo group (n = 33). The participants underwent 4 TENS sessions, and the effect on pain was assessed using a visual analogue scale (VAS pain). Lung function was measured by spirometry.

Results

There were no differences between the 2 groups regarding time of surgery and time of mechanical ventilation. Compared to placebo, TENS reduced pain in the intervention group (p = 0.001). Regarding the effect of electroanalgesia on pulmonary function, the spirometric parameters were similar between the groups. However, regarding muscle strength between the preoperative and postoperative periods, maximal inspiratory pressure (MIP) was maintained in the intervention group and decreased in the placebo group (p = 0.03). Compared with that in the intervention group, the respiratory rate in the placebo group increased during the application of TENS (p = 0.003).

Conclusion

Electroanalgesia reduces pain in patients who underwent bariatric surgery. Importantly, in these patients, the MIP is maintained between the preoperative and postoperative periods. However, electroanalgesia does not contribute to improvements in spirometric data. This trial is registered with NCT04800640.

Transcutaneous electrical nerve stimulation (TENS) for the treatment of renal colic in the emergency department: A randomized, double-blind, placebo-controlled trial

STUDY OBJECTIVE

To determine the analgesic efficacy of TENS treatment in patients with renal colic in the emergency department (ED).

METHODS

This double-blind, randomized controlled trial was conducted in a tertiary care ED. Patients with a definitive diagnosis of renal colic were assigned (1:1) as randomized to receive the real TENS with frequency 100 Hz, pulse width 200 microseconds, voltage 2 mA, or placebo with sham TENS. Pain intensity was measured using visual analog scales (VAS) at baseline, after 15 and 30th minutes.

RESULTS

A total of 100 patients were included in the final analysis: 50 patients treated with real TENS and 50 patients treated with sham TENS. VAS scores in both groups were similar at baseline. The mean reduction in VAS score at 15 min was 33.3 ± 17.6 (95% Confidence interval (CI): 28.3 to 38.3) for the real TENS group and 14.9 ± 11.6 (95% CI 11.6 to 18.2) for the sham TENS group (mean difference: 18.4 (95% CI: 12.5 to 24.4, P < 0.0001). The mean reduction in VAS score at 30 min was 63.7 ± 21.1 (95% CI: 57.7 to 69.7) for the real TENS group and 14.9 ± 16.2 (95% CI: 19.5 to 10.3) for the sham TENS group (mean difference: 48.8, 95% CI: 41.4 to 56.3, P < 0.0001). Four patients (8%) in the real TENS group and 24 patients (48%) in the sham TENS group required the rescue medication after 30th minutes.

CONCLUSIONS

TENS is effective for acute pain treatment in renal colic patients in the ED. TENS therapy could be a treatment option for renal colic.

Efficacy of Transcutaneous Electrical Nerve Stimulation for Postoperative Pain, Pulmonary Function, and Opioid Consumption Following Cardiothoracic Procedures: A Systematic Review

OBJECTIVE

Transcutaneous electrical nerve stimulation (TENS) is a minimally invasive method for treating pain. In the most recent review published in 2012, TENS was associated with increased pain relief following cardiothoracic surgery when compared to standard multimodal analgesia. The purpose of this systematic review and meta-analysis is to determine if adding TENS to current pain management practices decreases pain and analgesic use and improves pulmonary function for postcardiothoracic surgery patients.

MATERIALS AND METHODS

CINAHL, MEDLINE, Cochrane Database of Systematic Reviews, PubMed, and ClinicalTrials.gov were searched using specific keywords. Covidence was used to screen, select studies, and extract data by two independent reviewers. The Cochrane Risk of Bias tool assessed risk of bias. Visual analog scale (VAS) and pulmonary function data were exported for meta-analysis using a random effects model.

RESULTS

The search yielded 38 articles. Eight randomized controlled trials met inclusion criteria for the literature review. Five studies were included in the meta-analysis of pain at 24, 48, and 72 hours postoperatively. Data were analyzed using the standard mean difference (SMD). TENS had a significant impact on VAS at rest (-0.76 SMD [95% confidence interval, CI = -1.06 to -0.49], p < 0.00001) and with coughing (-1.11 SMD [95% CI = -1.64 to -0.56], p < 0.0001). FEV1 improved after 72 hours (1.00 SMD [95% CI = 0.66-1.35], p < 0.00001), as did forced vital capacity (1.16 SMD [95% CI = 0.23-2.10], p = 0.01).

CONCLUSION

The addition of TENS therapy to multimodal analgesia significantly decreases pain following cardiothoracic surgery, increases the recovery of pulmonary function, and decreases the use of analgesics.

Does TENS Reduce the Intensity of Acute and Chronic Pain? A Comprehensive Appraisal of the Characteristics and Outcomes of 169 Reviews and 49 Meta-Analyses

Background and Objectives: Uncertainty about the clinical efficacy of transcutaneous electric nerve stimulation (TENS) to alleviate pain spans half a century. There has been no attempt to synthesise the entire body of systematic review evidence. The aim of this comprehensive review was to critically appraise the characteristics and outcomes of systematic reviews evaluating the clinical efficacy of TENS for any type of acute and chronic pain in adults. Materials and Methods: We searched electronic databases for full reports of systematic reviews of studies, overviews of systematic reviews, and hybrid reviews that evaluated the efficacy of TENS for any type of clinical pain in adults. We screened reports against eligibility criteria and extracted data related to the characteristics and outcomes of the review, including effect size estimates. We conducted a descriptive analysis of extracted data. Results: We included 169 reviews consisting of eight overviews, seven hybrid reviews and 154 systematic reviews with 49 meta-analyses. A tally of authors' conclusions found a tendency toward benefits from TENS in 69/169 reviews, no benefits in 13/169 reviews, and inconclusive evidence in 87/169 reviews. Only three meta-analyses pooled sufficient data to have confidence in the effect size estimate (i.e., pooled analysis of >500 events). Lower pain intensity was found during TENS compared with control for chronic musculoskeletal pain and labour pain, and lower analgesic consumption was found post-surgery during TENS. The appraisal revealed repeated shortcomings in RCTs that have hindered confident judgements about efficacy, resulting in stagnation of evidence. Conclusions: Our appraisal reveals examples of meta-analyses with 'sufficient data' demonstrating benefit. There were no examples of meta-analyses with 'sufficient data' demonstrating no benefit. Therefore, we recommend that TENS should be considered as a treatment option. The considerable quantity of reviews with 'insufficient data' and meaningless findings have clouded the issue of efficacy. We offer solutions to these issues going forward.

Resolving Long-Standing Uncertainty about the Clinical Efficacy of Transcutaneous Electrical Nerve Stimulation (TENS) to Relieve Pain: A Comprehensive Review of Factors Influencing Outcome

Pain is managed using a biopsychosocial approach and pharmacological and non-pharmacological treatments. Transcutaneous electrical nerve stimulation (TENS) is a technique whereby pulsed electrical currents are administered through the intact surface of the skin with the intention of alleviating pain, akin to 'electrically rubbing pain away'. Despite over 50 years of published research, uncertainty about the clinical efficacy of TENS remains. The purpose of this comprehensive review is to critically appraise clinical research on TENS to inform future strategies to resolve the 'efficacy-impasse'. The principles and practices of TENS are described to provide context for readers unfamiliar with TENS treatment. The findings of systematic reviews evaluating TENS are described from a historical perspective to provide context for a critical evaluation of factors influencing the outcomes of randomized controlled trials (RCTs); including sample populations, outcome measures, TENS techniques, and comparator interventions. Three possibilities are offered to resolve the impasse. Firstly, to conduct large multi-centered RCTs using an enriched enrolment with randomized withdrawal design, that incorporates a 'run-in phase' to screen for potential TENS responders and to optimise TENS treatment according to individual need. Secondly, to meta-analyze published RCT data, irrespective of type of pain, to determine whether TENS reduces the intensity of pain during stimulation, and to include a detailed assessment of levels of certainty and precision. Thirdly, to concede that it may be impossible to determine efficacy due to insurmountable methodological, logistical and financial challenges. The consequences to clinicians, policy makers and funders of this third scenario are discussed. I argue that patients will continue to use TENS irrespective of the views of clinicians, policy makers, funders or guideline panel recommendations, because TENS is readily available without prescription; TENS generates a pleasant sensory experience that is similar to easing pain using warming and cooling techniques; and technological developments such as smart wearable TENS devices will improve usability in the future. Thus, research is needed on how best to integrate TENS into existing pain management strategies by analyzing data of TENS usage by expert-patients in real-world settings.

Effect of transcutaneous electrical nerve stimulation on quality of recovery and pain after abdominal hysterectomy

Background and Aims:

Transcutaneous electrical nerve stimulation (TENS) is a noninvasive complementary therapy for postoperative pain management. The effect of TENS on quality of recovery (QoR) and pain treatment in the early postoperative period is not well documented. The aim of this study was to evaluate the effect of TENS on postoperative QoR and pain in patients who had undergone a total abdominal hysterectomy with bilateral salpingo-oophorectomy (TAH + BSO).

Material and Methods:

Fifty-two patients were randomized into two groups: control (sham TENS treatment) and TENS (TENS treatment). QoR, dynamic pain, and static pain were evaluated after surgery.

Results:

The QoR score was significantly higher in the TENS group as compared with that in the control group (P = 0.029). Pain scores during coughing (dynamic pain) were significantly less in TENS group compared to control group (P <0.001). However, there was no between-group difference in pain scores at rest (static pain) or total analgesic consumption (P = 0.63 or P = 0.83, respectively).

Conclusion:

TENS may be a valuable tool to improve patients' QoR and dynamic pain scores after TAH + BSO.

The Hua-Shan rehabilitation program after contralateral seventh cervical nerve transfer for spastic arm paralysis

Purpose: To propose the novel Hua-Shan rehabilitation program for patients undergoing the contralateral seventh cervical nerve transfer, and explore the influence of different rehabilitation on the postoperative recovery.Materials and methods: The Hua-Shan program was established in consideration of the three elements: the nerve regeneration, brain plasticity and group therapy. Its effect was evaluated by comparing the postoperative recovery of the hemorrhagic stroke survivors among the following three groups: Group A-standard Hua-Shan program after surgery; Group B-standard traditional program after surgery; Group C-no standard rehabilitation after surgery.Results: Significantly better functions after surgery were detected in all the groups, while the absence of standard rehabilitation massively offset the benefits of the surgery. Furthermore, the Hua-Shan program showed advantage over the traditional rehabilitation, which may largely be attributed to its improvements for the fine action of wrist&finger.Conclusions: The Hua-Shan program provided the opportunity to maximize the benefits of contralateral seventh cervical nerve transfer.IMPLICATIONS FOR REHABILITATIONStandard rehabilitation plays key roles in the recovery process for patients undergoing contralateral seventh cervical nerve transfer.The Hua-Shan program targeting nerve regeneration, brain plasticity and group therapy further improved the benefits of patients undergoing contralateral seventh cervical nerve transfer.

Enhanced transcutaneous electrical nerve stimulation achieved by a localized virtual bipole: a computational study of human tibial nerve stimulation

OBJECTIVE

Electrical neuromodulation is a clinically effective therapeutic instrument, currently expanding into newer indications and larger patient populations. Neuromodulation technologies are also moving towards less invasive approaches to nerve stimulation. In this study, we investigated an enhanced transcutaneous electrical nerve stimulation (eTENS) system that electrically couples a conductive nerve cuff with a conventional TENS electrode. The objectives were to better understand how eTENS achieves lower nerve activation thresholds, and to test the feasibility of applying eTENS in a human model of peripheral nerve stimulation.

APPROACH

A finite element model (FEM) of the human lower leg was constructed to simulate electrical stimulation of the tibial nerve, comparing TENS and eTENS. Key variables included surface electrode diameter, nerve cuff properties (conductivity, length, thickness), and cuff location. Enhanced neural excitability was predicted by relative excitability (RE > 1), derived using either the activating function (AF) or the nerve activation threshold (MRG model).

MAIN RESULTS

Simulations revealed that a localized 'virtual bipole' was created on the target nerve, where the isopotential surface of the cuff resulted in large potential differences with the surrounding tissue. The cathodic part (nerve depolarization) of the bipole enhanced neural excitability, predicted by RE values of up to 2.2 (MRG) and 5.5 (AF) when compared to TENS. The MRG model confirmed that action potentials were initiated at the cathodic edge of the nerve cuff. Factors contributing to eTENS were larger surface electrodes, longer cuffs, cuff conductivity (>1×10³ S m^-1), and cuff position relative to the cathodic surface electrode.

SIGNIFICANCE

This study provides a theoretical basis for designing and testing eTENS applied to various neural targets and data suggesting function of eTENS in large models of nerve stimulation. Although eTENS carries key advantages over existing technologies, further work is needed to translate this approach into effective clinical applications.

The clinical efficacy of transcutaneous electrical nerve stimulation (TENS) for acute and chronic pain: a protocol for a meta-analysis of randomised controlled trials (RCTs)

INTRODUCTION

The aim of this systematic review with meta-analysis is to evaluate the clinical efficacy of transcutaneous electrical nerve stimulation (TENS) for any type of acute and chronic pain in adults.

METHODS AND ANALYSIS

We intend to search electronic databases (Cochrane Library, MEDLINE, Embase, CINAHL, PsycINFO, LILACS, PEDRO, Web of Science, AMED and SPORTDiscus) from inception to the present day to identify all randomised controlled trials (RCT) on the use of TENS in adults for any type of pain including acute pain, chronic pain and cancer-related pain. We will screen the RCTs against eligibility criteria for inclusion in our review. Two reviewers will independently undertake RCT selection, data extraction and risk of bias assessment. Primary outcomes will be: (i) participant-reported pain relief of ≥30% expressed as frequency (dichotomous) data; and (ii) participant-reported pain intensity expressed as mean (continuous) data. We will conduct meta-analyses to determine risk ratio for dichotomous data, and mean difference (MD) or standardised MD for continuous data for TENS versus placebo TENS, no treatment or waiting list control, standard of care, and other treatments. Subgroup analyses will include different pain conditions (eg, acute vs chronic), TENS intensity, during versus after TENS, TENS as a sole treatment versus TENS in combination with other treatments and TENS administered as a single dose versus repetitive dose.

ETHICS AND DISSEMINATION

This systematic review will not use data from individual participants, and the results will be disseminated in a peer-reviewed publication and presented at a conference.

PROSPERO REGISTRATION NUMBER

CRD42019125054.

Efficacy of Transcutaneous Electronic Nerve Stimulation in Postoperative Analgesia After Pulmonary Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

The aim of the study was to identify the analgesic efficacy and safety of transcutaneous electronic nerve stimulation in postoperative pain after pulmonary surgery.

DESIGN

Electronic databases (PubMed, Embase, Web of Science, and CENTRAL) were systematically searched from their inception to June 2019. The continuous variables were pooled as the weighted mean difference with correlated 95% confidence interval. Results were recognized as significant when a P value is less than 0.05. Subgroup analyses, sensitivity analyses, and quality assessment were performed.

RESULTS

Altogether, 10 studies were included. The pooled results indicated that transcutaneous electronic nerve stimulation group conferred lower pain intensity score on the first postoperative day (weighted mean difference = -0.93, 95% confidence interval = -1.56 to -0.30, P = 0.004), postoperative day 2 (weighted mean difference = -1.00, 95% confidence interval = -1.64 to -0.35, P = 0.002), postoperative day 3 (weighted mean difference = -0.92, 95% confidence interval = -1.76 to -0.09, P = 0.03), postoperative day 4 (weighted mean difference = -0.90, 95% confidence interval = -1.24 to -0.56, P < 0.001), and postoperative day 5 (weighted mean difference = -1.39, 95% confidence interval = -2.20 to -0.57, P < 0.001) compared with the placebo transcutaneous electronic nerve stimulation group. No publication bias was found. No significant discovery was obtained in sensitivity analyses.

CONCLUSIONS

Transcutaneous electronic nerve stimulation might be an effective supplementary analgesic regimen in multimodal analgesia to decrease pain intensity after pulmonary surgery.

Efficacy of different-frequency TEAS on acute pain after the total knee arthroplasty: a study protocol for a parallel group randomized trial

BACKGROUND

Total knee arthroplasty (TKA) is an optimal option for patients with middle-to-end-stage knee osteoarthritis. However, the management of postoperative acute pain remains inefficient. Transcutaneous electrical acupoint stimulation (TEAS) is a nonpharmacological method to manage postoperative acute pain. Different frequencies of TEAS have been tested using varying parameters, but the optimal analgesic frequency remains controversial. The aim of this study was to explore the optimal analgesic frequency of TEAS for treating acute pain after the primary unilateral TKA.

METHODS/DESIGN

This is a double-blind, randomized controlled trial. A total of 156 patients are randomly assigned to: G1, 5 Hz TEAS; G2, 100 Hz TEAS; G3, mixed TEAS (alternative use of daily 5 Hz and 100 Hz TEAS) and G4, placebo TEAS. In the G1, G2 and G3 groups, TEAS is conducted at acupoints SP9 and GB34 of the leg that was operated on (at a wave of continuous, balanced and asymmetrical biphasic square, with a pulse width of 200 μs, and a strong but comfortable current) for 30 min prior to a 30-min rehabilitation session per day for 2 weeks. In G4 group, TEAS is delivered at a strong but comfortable current for 30 s, then the current is gradually decreased to none over the next 15 s. The primary outcomes are measured before surgery, at baseline (POD 3, before TEAS intervention), week 1 and 2 after TEAS intervention with the Numeric Pain Rating Scale and The American Knee Society Score. The secondary outcomes include: (1) Active range of motion of the knee that was operated on; (2) Surface electromyography of both quadriceps; (3) Modified 30-s sit to stand test; (4) Additional usage of analgesia; and (5) SF-36. The additional outcomes include: (1) Patients' satisfaction rate; (2) Patient's expectation rate; and (3) Incidence of analgesia-related side effects. To test the blinding of participants and assessors, they are asked to guess whether the subjects received active or placebo TEAS within 5 min after the latest intervention. The safety and financial cost of TEAS are assessed.

DISCUSSION

Mixed TEAS has more favorable effect on acute pain control than the placebo or 5 Hz or 100 Hz TEAS.

TRIAL REGISTRATION

ChiCTR1800016347 . Date of registration was 26 May 2018. Retrospectively registered.

Bioelectric neuromodulation for gastrointestinal disorders: effectiveness and mechanisms

The gastrointestinal tract has extensive, surgically accessible nerve connections with the central nervous system. This provides the opportunity to exploit rapidly advancing methods of nerve stimulation to treat gastrointestinal disorders. Bioelectric neuromodulation technology has considerably advanced in the past decade, but sacral nerve stimulation for faecal incontinence currently remains the only neuromodulation protocol in general use for a gastrointestinal disorder. Treatment of other conditions, such as IBD, obesity, nausea and gastroparesis, has had variable success. That nerves modulate inflammation in the intestine is well established, but the anti-inflammatory effects of vagal nerve stimulation have only recently been discovered, and positive effects of this approach were seen in only some patients with Crohn's disease in a single trial. Pulses of high-frequency current applied to the vagus nerve have been used to block signalling from the stomach to the brain to reduce appetite with variable outcomes. Bioelectric neuromodulation has also been investigated for postoperative ileus, gastroparesis symptoms and constipation in animal models and some clinical trials. The clinical success of this bioelectric neuromodulation therapy might be enhanced through better knowledge of the targeted nerve pathways and their physiological and pathophysiological roles, optimizing stimulation protocols and determining which patients benefit most from this therapy.

New Advances in Acute Postoperative Pain Management

PURPOSE OF REVIEW

Postoperative pain remains one of the most common challenges following inpatient and outpatient surgeries. With our advances in modern medicine, pain following surgical procedures still remains a challenge, though significant accomplishments have been made over the past few decades. This article highlights some of the promising new advances and approaches in postoperative pain management.

RECENT FINDINGS

Over the last decade, Enhanced Recovery after Surgery (ERAS) pathways and protocols are becoming the benchmark standards for enhancing postoperative recovery. Multimodal analgesia (MMA) is an essential component of such care. Further, in the wake of serious and persistent concern on the opioid epidemic in the USA, there has been a recent renewal of interest in non-opioid alternatives or adjuncts in controlling postoperative pain, often in the context of MMA. Intravenous (IV) acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), magnesium, ketamine, dexmedetomidine, liposomal bupivacaine, and newer neuraxial and peripheral regional techniques as well as patient-controlled modalities are gaining importance. Gabapentinoids have become popular but recent meta-analytic reviews have cast doubt on their routine use in perioperative settings. Among opioids, sublingual sufentanil, IV oxycodone, and iontophoretic transdermal fentanyl hold promise. Acupuncture and transcutaneous electrical nerve stimulation may be useful as adjuncts in MMA packages. Genetic testing, derivatives of herbal preparations, and an extended role of acute pain services may emerge as potential areas of importance in the future. There are, however, critical gaps in good quality evidence in many of the practice guideline recommendations. In the era of opioid epidemic, several lines of evidence have emerged to support non-opioid-based drugs and approaches along with a few newer opioid formulations for postoperative pain management, although more research is needed to find the right balance of efficacy and safety.