Effectiveness of fixed-site high-frequency transcutaneous electrical nerve stimulation in chronic pain: a large-scale, observational study

Alternative pain management via endocannabinoids in the time of the opioid epidemic: Peripheral neuromodulation and pharmacological interventions

The use of opioids in pain management is hampered by the emergence of analgesic tolerance, which leads to increased dosing and side effects, both of which have contributed to the opioid epidemic. One promising potential approach to limit opioid analgesic tolerance is activating the endocannabinoid system in the CNS, via activation of CB1 receptors in the descending pain inhibitory pathway. In this review, we first discuss preclinical and clinical evidence revealing the potential of pharmacological activation of CB1 receptors in modulating opioid tolerance, including activation by phytocannabinoids, synthetic CB1 receptor agonists, endocannabinoid degradation enzyme inhibitors, and recently discovered positive allosteric modulators of CB1 receptors. On the other hand, as non-pharmacological pain relief is advocated by the US-NIH to combat the opioid epidemic, we also discuss contributions of peripheral neuromodulation, involving the electrostimulation of peripheral nerves, in addressing chronic pain and opioid tolerance. The involvement of supraspinal endocannabinoid systems in peripheral neuromodulation-induced analgesia is also discussed. LINKED ARTICLES: This article is part of a themed issue on Advances in Opioid Pharmacology at the Time of the Opioid Epidemic. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v180.7/issuetoc.

Advances in applications of head mounted devices (HMDs): Physical techniques for drug delivery and neuromodulation

Head-mounted medical devices (HMDs) are disruptive inventions representing laboratories and clinical institutions worldwide are climbing the apexes of brain science. These complex devices are inextricably linked with a wide range knowledge containing the Physics, Imaging, Biomedical engineering, Biology and Pharmacology, particularly could be specifically designed for individuals, and finally exerting integrated bio-effect. The salient characteristics of them are non-invasive intervening in human brain's physiological structures, and alterating the biological process, such as thermal ablating the tumor, opening the BBB to deliver drugs and neuromodulating to enhance cognitive performance or manipulate prosthetic. The increasing demand and universally accepted of them have set off a dramatic upsurge in HMDs' studies, seminal applications of them span from clinical use to psychiatric disorders and neurological modulation. With subsequent pre-clinical studies and human trials emerging, the mechanisms of transcranial stimulation methods of them were widely studied, and could be basically came down to three notable approach: magnetic, electrical and ultrasonic stimulation. This review provides a comprehensive overviews of their stimulating mechanisms, and recent advances in clinic and military. We described the potential impact of HMDs on brain science, and current challenges to extensively adopt them as promising alternative treating tools.

High Versus Low Frequency Transcutaneous Electric Nerve Stimulation On Chronic Venous Lower Limb Ulceration Randomized Controlled Trial

The major objective of the current paper is to trace and investigate which method is more effective whether the high or the low Transcutaneous electric Nerve Stimulations (TENS) on venous ulcers. A single-blinded, randomized, and controlled trial was done successfully. Sixty venous ulcer patients were divided randomly into three groups; Group (A): control group, Group(B): High-TENS group, and Group(C): Low-TENS group. Group (A), contains twenty participants who received routine medical care and dressing. As for group (B), includes twenty participants who obtained high-frequency TENS; Frequency (80-120) HZ, Intensity (15 - 30 amp), Pulse duration 250 Micro sec, 60 min per session with routine medical care and dressing. The third group (c) L-TENS, encompasses twenty participants who received low-frequency TENS (1-5) HZ; Intensity (30 -80 amp), Pulse duration 250 Micro sec, 60 min per session with routine medical care and dressing. All the participants were examined before and after two months of intervention; four weeks (post1), then after eight weeks (post2). Participants were examined by using (image j) to measure the ulcer area. Saline was used for measuring the ulcer volume, and a visual analog scale was adopted to evaluate pain. After drawing a comparison among the three groups after four weeks and after eight weeks of treatment, a statistically significant decrease (P <0.05) in wound surface area, wound volume, and pain in favor of L-TENS was noticed. It has been found that L- TENS is more effective than H -TENS and is highly recommended in the treatment protocol for such debilitating conditions.

Effects of Wearable Transcutaneous Electrical Nerve Stimulation on Fibromyalgia: A Randomized Controlled Trial

Purpose

Fibromyalgia is a chronic condition characterized by widespread pain and interference with daily activities. The aim of this study is to assess the benefit of transcutaneous electrical nerve stimulation (TENS) for persons diagnosed with fibromyalgia.

Patients and Methods

Adults meeting diagnostic criteria for fibromyalgia were randomized in a double-blind trial to receive either an active (n=62) or sham (n=57) wearable TENS device for 3-months. Subjects were classified as having lower or higher pain sensitivity by Quantitative Sensory Testing (QST). Patient Global Impression of Change (PGIC, primary outcome) and secondary efficacy measures including Fibromyalgia Impact Questionnaire (FIQR), Brief Pain Inventory (BPI) and painDETECT questionnaire (PDQ) were assessed at baseline, 6-weeks and 3-months. Treatment effects were determined by a mixed model for repeated measures (MMRM) analysis of the intention-to-treat (ITT) population (N=119). A pre-specified subgroup analysis of pain sensitivity was conducted using an interaction term in the model.

Results

No differences were found between active and sham treatment on PGIC scores at 3-months (0.34, 95% CI [−0.37, 1.04], p=0.351) in the ITT population. However, in subjects with higher pain sensitivity (n=60), PGIC was significantly greater for active treatment compared to sham (1.19, 95% CI [0.24, 2.13], p=0.014). FIQR total score (−7.47, 95% CI [−12.46, −2.48], p=0.003), FIQR pain item (−0.62, 95% CI [−1.17, −0.06], p=0.029), BPI Interference (−0.70, 95% CI [−1.30, −0.11], p=0.021) and PDQ (−1.69, 95% CI [−3.20, −0.18], p=0.028) exhibited significant improvements for active treatment compared to sham in the ITT population. Analgesics use was stable and comparable in both groups.

Conclusion

This study demonstrated modest treatment effects of reduced disease impact, pain and functional impairment from wearable TENS in individuals with fibromyalgia. Subjects with higher pain sensitivity exhibited larger treatment effects than those with lower pain sensitivity. Wearable TENS may be a safe treatment option for people with fibromyalgia.

Clinicaltrials.gov Registration

NCT03714425.

Efficacy of a combination of hypnosis and transcutaneous electrical nerve stimulation for chronic non-cancer pain: A randomized controlled trial

BACKGROUND

Chronic non-cancer pain, which persists for at least three months, seriously affects quality of life. Chronic non-cancer pain patients are usually managed by a multidisciplinary team using pharmacological and non-pharmacological strategies. Nurses perform transcutaneous electrical nerve stimulation (TENS) and hypnosis, which are widely used in France for the treatment of chronic pain in pain departments.

OBJECTIVE

To assess pain relief at three months, comparing a simultaneous combination of hypnosis and TENS (intervention) with TENS alone (control).

DESIGN

Randomized controlled trial.

METHODS

Patients aged 18-80 years, suffering from chronic peripheral neuropathic and/or nociceptive non-cancer pain were included (September 2013 to May 2017) and followed for six months. The primary outcome was the pain intensity difference (by visual analog scale score) between month 3 and baseline. The secondary outcomes, assessed at months 3 and 6, were SF36 score, analgesics consumption and number of TENS sessions performed at home (last seven days).

RESULTS

Seventy-two patients were included, suffering from a combination of chronic non-cancer nociceptive and neuropathic pain, with a mean pain intensity of about sixty out of a hundred. The results show an important pain reduction (forty percent) in both groups at 3 months. No significant difference was observed between the control and intervention groups. Similarly, SF36 score, change in analgesic intake and patient compliance did not differ significantly between groups.

CONCLUSIONS

This is the first randomized controlled study showing a decrease of pain intensity and a high level of compliance with transcutaneous electrical nerve stimulation alone or associated to hypnosis. The combination does not seem to be more efficient than transcutaneous electrical nerve stimulation alone. Chronic non-cancer pain remains a major issue and a substantial proportion of patients do not appear to benefit from interventions.

IMPACT

This study increases our understanding of the combination of two non-pharmacological methods in chronic non-cancer pain patients. The combination of the two non-pharmacological strategies did not appear to be more efficient than one alone. Further research on non-pharmacological treatments targeting to patient's characteristics are needed to find appropriate strategies in patients with complex multidimensional pain conditions. Clinical Trial Number: NCT01944150 (Sept. 17, 2013).

Transcutaneous Electrical Nerve Stimulation for the Long-Term Treatment of Ocular Pain

PURPOSE

Ocular pain is a debilitating condition that is challenging to treat as therapies that target the ocular surface are often ineffective. We previously reported a short-term reduction in ocular pain after one periocular transcutaneous electrical nerve stimulation (TENS) session. The current study aims to elucidate the long-term effect of TENS on ocular pain.

MATERIALS AND METHODS

Fourteen individuals with eye pain were identified as candidates for a TENS device (RS Medical, Vancouver) for home use after a successful trial in clinic between February 2018 and July 2019 at the Miami Veterans Administration Hospital or University of Miami. Ten of the 14 patients were included in this retrospective review, based on the inclusion of receiving and using the device for a minimum of three months. The median age of the ten patients was 47.5 years, range 32-73 years, and eight were male. The main outcome measures were 1) frequency of long-term integration of TENS into ocular pain management and 2) patient reported ocular pain intensity (0-10) pre- vs. post-treatment.

RESULTS

Patients reported an initial median use of the device 14.0 times per week and over time reducing the frequency to 3.0 times per week. All reported that the TENS unit was successfully incorporated into their ocular pain management routine for at least three months (median duration of use 6.5 months, range 3-14 months). Nine of ten patients reported subjective pain reduction with use of the TENS device at home. Overall, pain intensity decreased by approximately 27.4% (mean rank = 5.6, Z = -2.1, p = 0.02) post- vs. pre-treatment. No adverse events associated with TENS were reported in any patient.

CONCLUSION

Our preliminary data suggest that TENS can be integrated into the long-term management of ocular pain with improvements in overall pain intensity.

Remote Analgesic Effects Of Conventional Transcutaneous Electrical Nerve Stimulation: A Scientific And Clinical Review With A Focus On Chronic Pain

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is a safe, noninvasive treatment for chronic pain that can be self-administered. Conventional TENS involves stimulation of peripheral sensory nerves at a strong, non-painful level. Following the original gate-control theory of pain, stimulation is typically near the target pain. As another option, remote stimulation may also be effective and offers potential advantages.

OBJECTIVE

This narrative review examines mechanisms underlying the remote analgesic effects of conventional TENS and appraises the clinical evidence.

METHODS

A literature search for English-language articles was performed on PubMed. Keywords included terms related to the location of TENS . Citations from primary references and textbooks were examined for additional articles.

RESULTS

Over 30 studies reported remote analgesic effects of conventional TENS. The evidence included studies using animal models of pain, experimental pain in humans, and clinical studies in subjects with chronic pain. Three types of remote analgesia were identified: at the contralateral homologous site, at sites distant from stimulation but innervated by overlapping spinal segments, and at unrelated extrasegmental sites.

CONCLUSION

There is scientific and clinical evidence that conventional TENS has remote analgesic effects. This may occur through modulation of pain processing at the level of the dorsal horn, in brainstem centers mediating descending inhibition, and within the pain matrix. A broadening of perspectives on how conventional TENS produces analgesia may encourage researchers, clinicians, and medical-device manufacturers to develop novel ways of using this safe, cost-effective neuromodulation technique for chronic pain.

Impact of transcutaneous electrical nerve stimulation on sleep in chronic low back pain: a real-world retrospective cohort study

Objective

The purpose of this study was to determine if transcutaneous electrical nerve stimulation (TENS) improves sleep in chronic low back pain (CLBP).

Background

There is uncertainty over the effectiveness of TENS in CLBP. In most studies, pain intensity has been the primary outcome measure. Although sleep abnormalities are common in CLBP, sleep outcomes have not been evaluated in most studies of TENS effectiveness. Subjective and objective sleep measures are often inconsistent in CLBP, suggesting that perception of sleep and actual sleep may differ.

Methods

This retrospective cohort study evaluated TENS for CLBP over 10 weeks. The source database included demographics, pain characteristics, pain intensity and interference on an 11-point numerical rating scale, adherence and actigraphic sleep data from real-world TENS users. Key inclusion criteria were CLBP with self-reported history of back injury and baseline pain interference with sleep ≥4. Study participants were stratified into improved and unimproved groups based on changes in pain interference with sleep (improved ≥1-point decrease). Actigraphic sleep metrics were compared between the two groups for weeks 1–2 and weeks 9–10.

Results

The inclusion criteria were met by 554 TENS users. There were 282 (50.9%) participants in the improved group and 272 (49.1%) in the unimproved group. The two groups had similar baseline characteristics and high TENS adherence. At the weeks 1–2 assessment, there were no differences among actigraphic sleep. At the weeks 9–10 assessment, there was a difference in total sleep time, with the improved group sleeping 29 minutes longer. In addition, the periodic leg movement (PLM) index was lower in the improved group.

Conclusion

Regular TENS improved self-reported and objective sleep measures in individuals with CLBP. When compared to the unimproved group, the improved group had longer total sleep time and fewer PLMs. Sleep may be an important outcome for TENS effectiveness in CLBP.

A Pilot Randomized Sham-Controlled Trial of MC5-A Scrambler Therapy in the Treatment of Chronic Chemotherapy-Induced Peripheral Neuropathy (CIPN)

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) affects 30% to 40% of patients with cancer with long-lasting disability. Scrambler therapy (ST) appeared to benefit patients in uncontrolled trials, so we performed a randomized sham-controlled Phase II trial of ST.

METHODS

The primary end point was "average pain" after 28 days on the Numeric Rating Scale. Each received ten 30-minute sessions of ST on the dermatomes above the painful areas, or sham treatment on the back, typically at L3-5 where the nerve roots would enter the spinal cord. Outcomes included the Brief Pain Inventory (BPI)-CIPN and the EORTC CIPN-20 scale. Patients were evaluated before treatment (day 0), day 10, and days 28, 60, and 90.

RESULTS

Data regarding pain as a primary outcome were collected for 33 of the 35 patients. There were no significant differences between the sham and the "real" ST group at day 10, 28, 60, or 90, for average pain, the BPI, or EORTC CIPN-20. Individual responses were noted during the ST treatment on the real arm, but most dissipated by day 30. There was improvement in the sensory subscale of the CIPN-20 at 2 months in the "real" group (P = .14). All "real" patients wanted to continue treatment if available.

DISCUSSION

We observed no difference between sham and real ST CIPN treatment. Potential reasons include at least the following: ST does not work; the sham treatment had some effect; small sample size with heterogeneous patients; misplaced electrodes on an area of nonpainful but damaged nerves; or a combination of these factors.

Microcurrent technology for rapid relief of sinus pain: a randomized, placebo-controlled, double-blinded clinical trial

Background

Transcutaneous electrical nerve stimulation has proven to be effective in alleviating chronic pain from facial myalgias. We evaluated the efficacy of a novel handheld microcurrent‐emitting device in short‐term, office‐based treatment of patients with sinus pain. This device, which is U.S. Food and Drug Administration (FDA)‐cleared, detects and treats regions corresponding to nerve fibers.

Methods

Randomized, double‐blinded, placebo‐controlled trial. Seventy‐one participants with facial pain attributed to self‐reported nasal/sinus disease were recruited from a tertiary rhinologic practice and the surrounding community and randomly assigned to either office‐based use of an active (n = 38) or placebo (n = 33) microcurrent emitter. The study device was repetitively applied by each patient to the bilateral periorbital areas for 5 minutes. A visual analogue scale (VAS) for pain severity was administered before, and 10 minutes after, treatment.

Results

Active microcurrent‐treated patients had a reduction in mean pain score from 5.63 pretreatment to 3.97 posttreatment (mean difference, 1.66; 95% confidence interval [CI], 1.20 to 2.12). Patients using the sham device also reported sinus pain reductions (mean difference, 0.91; 95% CI, 0.61 to 1.21). However, the active device demonstrated a significantly greater reduction in pain compared to sham (0.75‐point difference, p = 0.007). Notably, 23.7% of patients using the active device had a reduction of 3 or more points by VAS compared to 0% of sham device patients (p = 0.003). One minor occurrence of transient facial skin erythema was noted.

Conclusion

This trial suggests that treatment of rhinologic facial pain using this noninvasive microcurrent device is safe and effective in providing rapid relief of nasal/sinus pain. Additional studies with longer term follow‐up are warranted.

Transcutaneous Electrical Nerve Stimulation (TENS) in the Emergency Department for Pain Relief: A Preliminary Study of Feasibility and Efficacy

Introduction

Given the high rates of opioid addiction and overdose in the United States, non-opioid means of treating pain are increasingly needed. Transcutaneous electrical nerve stimulation (TENS) therapy is an effective non-opioid modality for treating pain, but has not yet been routinely used in emergency department (ED) settings. In this study we asked the following questions: Are TENS units a feasible treatment for pain in the ED? How effective are TENS units for the management of pain in a general ED population?

Methods

At our institution, we performed a pilot study using TENS units for pain. Patients in the ED were given, at the discretion of the ED provider, TENS units for the treatment of pain. Patients could be included for acute or chronic pain on whatever part of the body that was safe to use with TENS.

Results

A chart review of patients receiving TENS units in the ED (n=110) revealed that TENS was useful in relieving pain, along with other treatments, in 99% of cases. When surveyed, 83% of patients reported a functional improvement while using the TENS, and 100% of patients would recommend a TENS unit to a family or friend. When surveyed, 100% of ED staff observed that TENS units were effective in treating pain for patients, and 97% would want to use them if they themselves were patients.

Conclusion

Overall, in this small pilot study, TENS units appeared to be effective in our ED for reducing pain, when added to standard treatment. Additional studies are needed to determine which conditions are most responsive to TENS therapy, and the magnitude of pain reduction when used alone.