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

Assessment of Integrative Therapeutic Methods for Improving the Quality of Life and Functioning in Cancer Patients-A Systematic Review

Background: Cancer rehabilitation represents a series of measures adopted for the recovery of psychological, emotional, social, and financial functioning in the case of cancer patients. The purpose of this study is to identify the main elements of therapeutic management in the field of medical rehabilitation, as well as integrative, complementary medicine and holistic approaches that can be performed on the oncological patient. Methods: This systematic literature review follows the methodology outlined in the "Preferred Reporting Items for Systematic Reviews and Meta-Analysis" ("PRISMA") statement, which is an internationally recognized and widely accepted standard. Results: Active rehabilitative therapies offer therapeutic options for improving the functioning and quality of life of oncological patients; these therapies comprehensively address both the physical and psychological aspects of the disease. This review also includes the latest novelties and nanotechnologies applied in oncological rehabilitation, for example, drugs (or supplements) inspired by nature. Conclusions: Physical and rehabilitation medicine, mostly using stimulating therapeutic methods, was recently added to the list of contraindications in the management of oncological patients, both as an approach to the pathological concept itself and as an approach to the main clinical consequences and functional aspects of oncological therapies. Integrative, complementary medicine presents an important therapeutic resource in the case of oncological patients. Advanced studies are needed in the future to further ascertain the role of these therapies.

Exploring the Rules of Related Parameters in Transcutaneous Electrical Nerve Stimulation for Cancer Pain Based on Data Mining

INTRODUCTION

This study aims to investigate the regularity of related parameters in the treatment of cancer pain using transcutaneous electrical nerve stimulation (TENS).

METHODS

A comprehensive literature search was conducted in databases such as PubMed, Cochrane Library, Embase, Web of Science, OVID, CNKI, CBM, VIP, and WANNGFANG from inception up to December 2022. A database was established, and data mining techniques were applied to analyze the relevant TENS parameters.

RESULTS

A total of 27 articles were included, encompassing nine current frequencies, four retention times, four treatment frequencies, and two wave types. On the basis of the analysis of parameter association rules, the most closely related parameter combination for clinical TENS in the treatment of cancer pain was a current frequency of 2/100 Hz, a treatment frequency of once a day, a retention time of 30 min, and the dilatational wave. Moreover, the study involved 22 acupuncture points distributed along 13 meridians. According to the analysis of acupuncture point association rules, Hegu (LI04), Zusanli (ST36), and Sanyinjiao (SP06) were the most closely related acupuncture points and could be used in combination for clinical TENS in cancer pain treatment. Furthermore, cluster analysis was conducted on acupuncture points with a frequency ≥ 5, resulting in three categories: the first category included Sanyinjiao (SP06), Zusanli (ST36), Hegu (LI04), Jiaji point, and Neiguan (PC06); the second category included Ashi point; and the third category included Back shu point.

CONCLUSION

In the treatment of cancer pain using TENS, it is recommended to use a current frequency of 2/100 Hz, a treatment frequency of once a day, a retention time of 30 min, and the dilatational wave. The electrode positions were primarily selected from Ashi point, Back shu point, Sanyinjiao (SP06), Zusanli (ST36), Hegu (LI04), Jiaji point, and Neiguan (PC06) to achieve the best analgesic effect.

Efficiency of Direct Transcutaneous Electroneurostimulation of the Median Nerve in the Regression of Residual Neurological Symptoms after Carpal Tunnel Decompression Surgery

Carpal tunnel syndrome (CTS) is the most frequent entrapment neuropathy. CTS therapy includes wrist immobilization, kinesiotherapy, non-steroidal anti-inflammatory drugs, carpal tunnel steroid injection, acupuncture, and physical therapy. Carpal tunnel decompression surgery (CTDS) is recommended after failure of conservative therapy. In many cases, neurological disorders continue despite CTDS. The aim of this study was to investigate the efficiency of direct transcutaneous electroneurostimulation (TENS) of the median nerve in the regression of residual neurological symptoms after CTDS. Material and Methods: 60 patients aged 28-62 years with persisting sensory and motor disorders after CTDS were studied; 15 patients received sham stimulation with a duration 30 min.; 15 patients received high-frequency low-amplitude TENS (HF TENS) with a duration 30 min; 15 patients received low-frequency high-amplitude TENS (LF TENS) with a duration 30 min; and 15 patients received a co-administration of HF TENS (with a duration of15 min) and LF TENS (with a duration of 15 min). Results: Our research showed that TENS significantly decreased the pain syndrome, sensory disorders, and motor deficits in the patients after CTDS. Predominantly, negative and positive sensory symptoms and the pain syndrome improved after the HF TENS course. Motor deficits, reduction of fine motor skill performance, electromyography changes, and affective responses to chronic pain syndrome regressed significantly after the LF TENS course. Co-administration of HF TENS and LF TENS was significantly more effective than use of sham stimulation, HF TENS, or LF TENS in patients with residual neurological symptoms after CTDS.

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.

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.

A comparative study between transcutaneous electrical nerve stimulation and pulsed electromagnetic field therapy in the management of post-herpetic neuralgia of the sciatic nerve

OBJECTIVES

To compare the efficacy of pulsed electromagnetic field therapy (PEMFT) versus transcutaneous electrical nerve stimulation (TENS) in the treatment of post-herpetic neuralgia of the sciatic nerve.

METHODS

A double-blinded randomized clinical study has included 56 patients (18 males and 38 females). Participants were randomly and equally assigned into 2 groups. Both groups received conventional physical therapy treatment. Moreover, group (A) has an additional TENS, and group (B) had PEMFT. Both modalities were applied once daily, 3 times a week for 20 minutes for 8 successive weeks. Visual analog scale (VAS) and carbamazepine intake (CMI) dose have been assessed before and after interventions.

RESULTS

There was a significant decrease in VAS and CMI post-treatment in group A and B compared with that pretreatment (P > .001). The percent decrease in VAS and CMI in group A were 72.44% and 69.47% respectively and that for group B was 68.95% and 67.94% respectively. The findings revealed a non-significant difference in VAS and CMI (P > .05) between groups. The Means of VAS and CMI were (2.4 ± 0.78, 204.5 ± 16.76 and 2.67 ± 0.9, 210.57 ± 16.5) in group A and group B respectively. The mean difference for VAS and CMI was (-0.27 and -6.07) between groups post-treatment respectively.

CONCLUSION

Both TENS and PEMFT were effective and nearly equivalent in improving the post-herpetic neuralgia of the sciatic nerve as measured by in VAS and CMI. Clinical recommendations should be highlighted to instigate the using of TENS and PEMFT in the management of post-herpetic neuralgia of the sciatic nerve.

Analgesic effects of high-frequency and low-frequency TENS currents in patients with distal neuropathy

Currently, diabetes mellitus (DM) is relevant problem, both for its prevalence and complications, including distal polyneuropathy (DPNP). At the same time, discussions continue on analgesic efficacy of transcutaneous electrical nerve stimulation (TENS) in DPNP. Aim of this study was to conduct a multi-faceted assessment of pain syndrome in these patients before and after TENS, taking into account levels of polyneuropathy, its severity and age of patients. The study was conducted in accordance with the research of the Federal State Budgetary Institution of the National Medical Research Center for Rehabilitation and Balneology of the Ministry of Health of the Russian Federation (CTR No. 121040100062-3) and with the permission of the Local Ethics Committee (IRB No. 2 dated 14.01.2021). The study included 75 patients with DM type II with DPNP, which are distributed into 3 groups of 25 people: Group 1a, patients received high–frequency TENS (HF); Group Ib, patients received low-frequency TENS (LF); as control, Group C received a standard method of pharmacological therapy without physiotherapy. Intensity of DPNP was evaluated before and after the course of treatment using a visual analog scale (VAS), the McGill Pain Questionnaire (MPQ), and a graphical linear analysis of pain on the neuropathic pain diagnostic questionnaire 4 (DN4) scale. TENS provides an analgesic effect that may exceed pharmacotherapy in terms of efficacy and safety. There was a 65.9% reduction in neuropathic pain according to VAS after a course of application, with the effects remaining up to 34% during the 6-month follow-up. HF TENS provided a higher significant analgesic effects than LF TENS, as it ensures the reduction of pain syndrome according to VAS by 25.8% (p <0.01), and total estimated characteristics - 35.5% (p <0.01), and touch - in at 58.1% (p = 0.001) and according to the scales of the MPQ (S) and DN4 - by 21% (p = 0.007). The observed differences in analgesic effects between HF TENS and LF TENS are based on analyses of pain in the immediate and long-term follow-up periods of type II DM patients with DPNP. These results, based on summation of the estimated parameters of the international pain scales support expectation of an expansion of the the use of analgesic TENS in aging patients suffering with DM of varying severity and extent of DPNP damage, a goal of great scientific and practical importance.

Novel Therapies for the Treatment of Neuropathic Pain: Potential and Pitfalls

Neuropathic pain affects more than one million people across the globe. The quality of life of people suffering from neuropathic pain has been considerably declining due to the unavailability of appropriate therapeutics. Currently, available treatment options can only treat patients symptomatically, but they are associated with severe adverse side effects and the development of tolerance over prolonged use. In the past decade, researchers were able to gain a better understanding of the mechanisms involved in neuropathic pain; thus, continuous efforts are evident, aiming to develop novel interventions with better efficacy instead of symptomatic treatment. The current review discusses the latest interventional strategies used in the treatment and management of neuropathic pain. This review also provides insights into the present scenario of pain research, particularly various interventional techniques such as spinal cord stimulation, steroid injection, neural blockade, transcranial/epidural stimulation, deep brain stimulation, percutaneous electrical nerve stimulation, neuroablative procedures, opto/chemogenetics, gene therapy, etc. In a nutshell, most of the above techniques are at preclinical stage and facing difficulty in translation to clinical studies due to the non-availability of appropriate methodologies. Therefore, continuing research on these interventional strategies may help in the development of promising novel therapies that can improve the quality of life of patients suffering from neuropathic pain.

Effects of Transcutaneous Electrical Nerve Stimulation on Pain and Chemotherapy-Induced Peripheral Neuropathy in Cancer Patients: A Systematic Review

Transcutaneous electrical nerve stimulation (TENS) is the usage of a mild electrical current through electrodes that stimulate nerves. Patients with malignancies experience pain and chemotherapy-induced peripheral neuropathy. A systematic review was performed to find research evaluating the effect of TENS on these two common symptoms decreasing the quality of life in cancer patients. PubMed, the Cochrane Central Register of Controlled Trials and EMBASE were searched. Original studies, namely randomized controlled trials, quasi-randomized controlled trials and controlled clinical trials, published between April 2007 and May 2020, were considered. The quality of the selected studies was assessed. Seven papers were incorporated in a qualitative synthesis, with 260 patients in total. The studies varied in terms of design, populations, endpoints, quality, treatment duration, procedures and follow-up period. Based on the results, no strict recommendations concerning TENS usage in the cancer patient population could be issued. However, the existing evidence allows us to state that TENS is a safe procedure that may be self-administered by the patients with malignancy in an attempt to relieve different types of pain. There is a need for multi-center, randomized clinical trials with a good methodological design and adequate sample size.

Clinical Experience of High Frequency and Low Frequency TENS in Treatment of Diabetic Neuropathic Pain in Russia

Background: Transcutaneous electrical nerve stimulation (TENS) is presently one of the main methods of treatment for neuropathic pain in type II diabetes mellitus. The discussion about which TENS frequency is more effective in the treatment of neuropathic pain has been ongoing for many years. Despite this, the response of different aspects of neuropathic pain to various TENS modalities has not been sufficiently studied. Aim: To analyze changes in characteristics of neuropathic pain depending on the frequency of TENS. Materials and methods: Seventy-five Russian diabetic patients with painful distal axonal neuropathy were enrolled in the study. Patients were assigned to three groups: in the HF TENS group, 25 patients received standard drug therapy (Alpha-lipoic acid, Pentoxifylline, Vitamin B12, Gabapentin) + high-frequency TENS (HF); in the LF TENS group, 25 patients received standard drug therapy (Alpha-lipoic acid, Pentoxifylline, Vitamin B12, Gabapentin) + low-frequency TENS (LF); in the control group, 25 patients underwent just standard drug therapy (Alpha-lipoic acid, Pentoxifylline, Vitamin B12, Gabapentin). Pain intensity was calculated before and after treatment with visual analogue scale (VAS), McGill pain questionnaire (MPQ), Douleur Neuropathique 4 Questions (DN4) and Pain Drawing. Results: TENS increased the therapeutic effect of standard drug therapy, in the treatment of neuropathic pain, by 65.9% and prolonged its efficacy by 31% for up to 6 months after treatment. HF TENS had a more pronounced analgesic effect than LF TENS based on VAS (34.7%), sensory (57.6%) MPQ dimensions and DN4 (21%). Affective MPQ dimension with the use of LF TENS was lower than HF TENS by 34.7% immediately after treatment, by 47.3% after 2 months and by 34.8% after 6 months of the follow-up period. Conclusion: There are significant differences between HF and LF TENS based on pain assessment using various pain scales. This reflects the distinctive effects of different TENS modalities on different aspects of neuropathic pain.

Comparison of the effective intensity of transcutaneous electrical nerve stimulation contralateral to a pain site for analgesia

[Purpose] This study aimed to compare the effectiveness of transcutaneous electrical nerve stimulation contralateral to the pain site for analgesia to identify the effective stimulation intensity. [Participants and Methods] Ten healthy adult females were recruited for the study. The same heat stimulation was applied to the left wrist joint of each participant to induce pain, serving as the control. Transcutaneous electrical nerve stimulation was then randomly administered to the right wrist, corresponding to the same dermatome contralateral to the painful site, at the intensities of comfortable stimulation, pain threshold, and maximum pain. The effect of transcutaneous electrical nerve stimulation was assessed using a Visual Analogue Scale and by analysis of heart rate variability. [Results] The Visual Analogue Scale score was significantly lower after stimulation with the maximum pain intensity than that for control, and there were no significant differences among the intensities of comfortable stimulation, pain threshold, and maximum pain. No significant differences were found among the groups in terms of high and low-to-high frequency components. [Conclusion] Transcutaneous electrical nerve stimulation at the maximum pain intensity to the dermatome area contralateral to that of the dorsal pain site of the left wrist was considered effective.

Pain modulation in the spinal cord

The sensory inflow from the periphery that triggers innocuous and painful sensations is highly complex, capturing key elements of the nature of any stimulus, its location, intensity, and duration, and converting this to dynamic action potential firing across a wide population of afferents. While sensory afferents are highly specialized to detect these features, their input to the spinal cord also triggers active processing and modulation there which determines its output, to drive the sensory percept experienced and behavioral responses. Focus on such active spinal modulation was arguably first introduced by Melzack and Wall in their Spinal Cord Gate Control theory. This theory has had a profound influence on our understanding of pain, and especially its processing, as well as leading directly to the development of clinical interventions, and its historical importance certainly needs to be fully recognized. However, the enormous progress we are making in the understanding of the function of the somatosensory system, means that it is time to incorporate these newly discovered features into a more complex and accurate model of spinal sensory modulation.

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.

Acute spinal cord injury: Pathophysiology and pharmacological intervention (Review)

Spinal cord injury (SCI) is one of the most debilitating of all the traumatic conditions that afflict individuals. For a number of years, extensive studies have been conducted to clarify the molecular mechanisms of SCI. Experimental and clinical studies have indicated that two phases, primary damage and secondary damage, are involved in SCI. The initial mechanical damage is caused by local impairment of the spinal cord. In addition, the fundamental mechanisms are associated with hyperflexion, hyperextension, axial loading and rotation. By contrast, secondary injury mechanisms are led by systemic and cellular factors, which may also be initiated by the primary injury. Although significant advances in supportive care have improved clinical outcomes in recent years, a number of studies continue to explore specific pharmacological therapies to minimize SCI. The present review summarized some important pathophysiologic mechanisms that are involved in SCI and focused on several pharmacological and non‑pharmacological therapies, which have either been previously investigated or have a potential in the management of this debilitating injury in the near future.

Short-Term Suppression of Somatosensory Evoked Potentials and Perceived Sensations in Healthy Subjects Following TENS

Transcutaneous electrical nerve stimulation (TENS) has been reported to alleviate pain in chronic pain patients. Currently, there is limited knowledge how TENS affects can cause cortical neuromodulation and lead to modulation of non-painful and painful sensations. Our aim was therefore to investigate the effect of conventional, high-frequency TENS on cortical activation and perceived sensations in healthy subjects. We recorded somatosensory evoked potentials (SEPs) and perceived sensations following high-frequency TENS (100 Hz) in 40 healthy subjects (sham and intervention group). The effect of TENS was examined up to an hour after the intervention phase, and results revealed significant cortical inhibition. We found that the magnitude of N100, P200 waves, and theta and alpha band power was significantly suppressed following the TENS intervention. These changes were associated with a simultaneous reduction in the perceived intensity and the size of the area where the sensation was felt. Although phantom limb pain relief previously has been associated with an inhibition of cortical activity, the efficacy of the present TENS intervention to induce such cortical inhibition and cause pain relief should be verified in a future clinical trial.

Design and Implementation of an Intelligent Analgesic Bracelet Based on Wrist-ankle Acupuncture

A flexible, multifunctional, and intelligent analgesic bracelet was proposed in this article to alleviate symptoms of pain. Based on the theory of wrist-ankle acupuncture in traditional Chinese medicine, transcutaneous electrical nerve stimulation is the technical basis of the method. A set of targeted circuit system capable of generating adjustable electrical stimulation signals to simulate filamentary acupuncture was designed. The system architecture includes a wireless communication module, a signal control module, a stimulus signal generation module, and a wearable, flexible bracelet. In addition, a pain assessment interface with a visual analog scale was designed to assess pain levels. Two comparative experiments were designed, involving a custom pain assessment scale and hand-held dolorimeter that were performed before and after wearing the bracelet to verify the analgesic effect of the bracelet. The results showed that the wrist-worn analgesic bracelet is significantly effective in alleviating pain in various parts of the human body.