Modulation between high- and low-frequency transcutaneous electric nerve stimulation delays the development of analgesic tolerance in arthritic rats

DeSantana JM, Santana-Filho VJ, Sluka KA. Modulation between high- and low-frequency transcutaneous electric nerve stimulation delays the development of analgesic tolerance in arthritic rats.

Objective

To investigate whether repeated administration of modulating frequency transcutaneous electric nerve stimulation (TENS) prevents development of analgesic tolerance.

Design

Knee joint inflammation (3% carrageenan and kaolin) was induced in rats. Either mixed or alternating frequency was administered daily (20min) for 2 weeks to the inflamed knee under light halothane anesthesia (1%-2%).

Setting

Laboratory.

Animals

Adult male Sprague-Dawley rats (N=36).

Intervention

Mixed- (4Hz and 100Hz) or alternating- (4Hz on 1 day; 100Hz on the next day) frequency TENS at sensory intensity and 100μs pulse duration.

Main Outcome Measures

Paw and joint withdrawal thresholds to mechanical stimuli were assessed before induction of inflammation, and before and after daily application of TENS.

Results

The reduced paw and joint withdrawal thresholds that occur 24 hours after the induction of inflammation were significantly reversed by the first administration of TENS when compared with sham treatment or to the condition before TENS treatment, which was observed through day 9. By the tenth day, repeated daily administration of either mixed- or alternating-frequency TENS did not reverse the decreased paw and joint withdrawal thresholds.

Conclusions

These data suggest that repeated administration of modulating frequency TENS leads to a development of opioid tolerance. However, this tolerance effect is delayed by approximately 5 days compared with administration of low- or high-frequency TENS independently. Clinically, we can infer that a treatment schedule of repeated daily TENS administration will result in a tolerance effect. Moreover, modulating low and high frequency TENS seems to produce a better analgesic effect and tolerance is slower to develop.     

The relationship between dorsal horn neurotransmitter content and allodynia in neuropathic rats treated with high-frequency transcutaneous electric nerve stimulation

Somers DL, Clemente FR. The relationship between dorsal horn neurotransmitter content and allodynia in neuropathic rats treated with high-frequency transcutaneous electric nerve stimulation. Arch Phys Med Rehabil 2003;84: 1575-83.Objective: To examine the relation between axon terminal neurotransmitter content in the dorsal horn and allodynia in neuropathic rats treated with high-frequency transcutaneous electric nerve stimulation (TENS).Design: A completely randomized experimental design. Two groups of rats received a chronic constriction injury to the right sciatic nerve, and 2 groups did not. The rats were either treated or not treated with TENS.Setting: Research laboratory.Animals: Adult male Sprague-Dawley rats (150-165g).Interventions: TENS was delivered daily for 1 hour to the chronic constriction injury rats or to the uninjured rats through self-adhesive electrodes applied to the skin innervated by the right dorsal rami of lumbar spinal nerves 1 to 6.Main Outcome Measures: Thermal and mechanical pain thresholds were assessed bilaterally in the hind paws of all rats twice before the chronic constriction injury surgery (baseline) and then 12 days after the surgery. An analogous time frame of assessment was used for rats that did not have chronic constriction injury surgery. Thermal and mechanical allodynia were expressed as difference scores between the pain thresholds of the right and left hind paws. These values were normalized to differences that existed between the 2 paws at baseline. The amino acid content of dorsal horn axon terminals was assessed bilaterally with high-pressure liquid chromatography, and values were normalized to wet weight.Results: The mean level of thermal and mechanical allodynia did not differ between the TENS-treated and untreated rats with chronic constriction injury. However, there was a significant relation between the dorsal horn, axon terminal content of glutamate (adjusted R²=.45, P<.01) and glycine (adjusted R²=.51, P<.005) and the magnitude of mechanical allodynia present in TENS-treated chronic constriction injury rats, but not in any other group. As axon terminal glutamate and glycine decreased in the right dorsal horn and increased in the left, mechanical allodynia was reduced or absent. When this trend was reversed, mechanical allodynia was more severe. Daily TENS also reduced the mean axon terminal content of aspartate, glutamate, and glycine bilaterally in the chronic constriction injury rats from the level observed in untreated neuropathic rats (P<.05).Conclusion: The variability in responsiveness of mechanical allodynia to daily TENS treatment in neuropathic rats is related to the axon terminal content of glutamate and glycine in the dorsal horn. These findings may help explain a similar variability in humans when TENS is used to treat neuropathic pain.     

Methodological quality in randomised controlled trials of transcutaneous electric nerve stimulation for pain: low fidelity may explain negative findings

The benefits of transcutaneous electrical nerve stimulation (TENS) for pain relief have not been reliably established, as most systematic reviews find poor methodological quality in many studies. The paradox within the evidence base for TENS is that despite identified sources of bias that may lead to an overestimation of treatment effects, no benefits for TENS can be clearly demonstrated. Conventional assessments of quality assume a single direction of bias, and little work has been undertaken examining other directions of bias. Our hypothesis was that low fidelity in studies (bias leading to an underestimation of treatment effects) may account for inconclusive findings. We included 38 studies from 3 recently published Cochrane systematic reviews that examined TENS for acute, chronic, and cancer pain. We extracted data relating to treatment allocation, application of TENS and to the assessment of outcomes. We quantified these data and judged this against standardised assessment criteria using a “traffic light” approach based on the number of studies reaching the standard. We identified significant sources of potential bias in both directions in relation to study design and implementation fidelity that have not been quantified previously. Suboptimal dosing of TENS and inappropriate outcome assessment were particularly prevalent weaknesses indicating low fidelity. We propose criteria for judging directions of bias in future studies of TENS that may be adapted to assess other trials in which implementation fidelity is important, such as other nonpharmacological interventions for pain.     

Low frequencies, but not high frequencies of bi-polar spinal cord stimulation reduce cutaneous and muscle hyperalgesia induced by nerve injury

Spinal cord stimulation (SCS) is an established treatment for neuropathic pain. However, SCS is not effective for all the patients and the mechanisms underlying the reduction in pain by SCS are not clearly understood. To elucidate the mechanisms of pain relief by SCS, we utilized the spared nerve injury model. Sprague–Dawley rats were anesthetized, the tibial and common peroneal nerves were tightly ligated, and an epidural SCS lead implanted in the upper lumbar spinal cord. SCS was delivered daily at one of 4 different frequencies (4 Hz, 60 Hz, 100 Hz, and 250 Hz) at approximately 85% of motor threshold 2 weeks after nerve injury for 4 days. Mechanical withdrawal threshold of the paw and compression withdrawal threshold of the hamstring muscles were measured before and after SCS on each day. All rats showed a decrease in withdrawal threshold of the paw and the muscle 2 weeks after nerve injury. Treatment with either 4 Hz or 60 Hz SCS significantly reversed the decreased withdrawal threshold of the paw and muscle. The effect was cumulative with a greater reversal by the fourth treatment when compared to the first treatment. Treatment with 100 Hz, 250 Hz or sham SCS had no significant effect on the decreased withdrawal threshold of the paw or muscle that normally occurs after nerve injury. In conclusion, SCS at 4 Hz and 60 Hz was more effective in reducing hyperalgesia than higher frequencies of SCS (100 Hz and 250 Hz); and repeated treatments result in a cumulative reduction in hyperalgesia.     

星状神经节阻滞配合经皮神经电刺激对突发性耳聋的康复作用

目的　探索星状神经节阻滞 (SGB)配合经皮神经电刺激 (TENS)对突发性耳聋 (SHL)的康复作用。方法　采用SGB配合TENS ,每日或隔日 1次 ,10次为 1个疗程 ,2个疗程之间间隔 3～ 5d。结果　在接受治疗的 94例患者中 ,94只耳 0 .2 5～ 4kHz治疗后的听力与治疗前相比显著提高 (P <0 .0 5 ) ,低频(0 .5kHz)优于高频 (2kHz ,4kHz) (P <0 .0 5 ) ;中、重度耳聋组和全聋组的听力损失dB数值治疗前、后自身比较有显著改变 (P <0 .0 5 ,P <0 .0 0 1) ;治疗总有效率 5 3 .2 % ,显效 8.5 1% ,有效 44 .7% ;伴有的耳鸣、眩晕症状也有所改善。以上过程中无 1例出现并发症。结论　SGB配合TENS对突发性耳聋导致的听力损失是一种有效、安全、可靠的康复治疗方法     

经皮电神经刺激配合磁热振疗法对脊髓损伤中枢性疼痛的疗效观察

目的:探讨经皮电神经刺激（TENS）合并磁热振治疗对脊髓损伤（SCI）中枢性疼痛的效果。方法：将36例SCI后中枢性疼痛患者随机分为观察组(A组)、TENS组（B组）、磁热振治疗组（C组）,每组12例。观察组采用经皮电神经刺激疗法合并磁热振治疗,TENS组只采用经皮电神经刺激疗法,磁热组只采用磁热振疗法。三组均在治疗前、治疗后采用简式McGill疼痛问卷对中枢性疼痛进行评定。结果：疗程结束后,患者疼痛的6项参数值均有降低,TENS组参数值低于磁热组,但两组差异并无显著性;观察组参数值显著低于TENS组或磁热振组（P<0.01）。结论：经皮电神经刺激合并磁热振疗法对治疗SCI后中枢性疼痛优于单纯的经皮电神经刺激疗法和磁热振疗法。     

经皮电神经刺激术刺激正常老年人穴位的脑功能性磁共振成像研究

目的探讨经皮电神经刺激术(TENS)改善老年性痴呆(AD)患者记忆和行为的机制。方法利用功能性磁共振方法观察正常人大脑对经皮电神经刺激术(TENS)刺激穴位的反应,刺激部位为左腿的"足三里"、"涌泉"和"太冲"穴,对6名正常老年人进行了脑部功能性磁共振成像。成像过程中,每名受试者分别接受了160 Hz的TENS刺激。结果TENS刺激正常老年人左腿的"足三里"、"涌泉"和"太冲"穴,正常老年人大脑仅在刺激"太冲"穴时可见脑区激活,它们是:下丘脑、BA6区、BA7区、BA31区、BA32区、BA38区。结论TENS可能通过激活上述结构改善老年性痴呆患者的记忆和行为。     

Pain relief by applying transcutaneous electrical nerve stimulation (TENS) during unsedated colonoscopy: A randomized double‐blind placebo‐controlled trial

Transcutaneous electrical nerve stimulation (TENS) is a noninvasive alternative to traditional pain treatments. TENS has been studied in the past as a pain reduction modality in colonoscopy with limited success. Reviews and meta‐analysis have shown that the inconclusive results of TENS may be due to the lack of randomized controlled trials and the difficulty in defining precise output parameters. The objective of this double‐blind randomized placebo‐controlled trial was to investigate the pain‐relieving effect of a new application of TENS in unsedated screening colonoscopy. Ninety patients undergoing unsedated screening colonoscopy were randomly allocated to one of three groups: a control group (n=30), a group to receive active TENS (n=30), or a group to receive placebo TENS (n=30). A visual analogue scale (VAS) and a five‐point Likert scale were used to assess pain 5min into the procedure and at the end of the procedure. The patient's bloating sensation during colonoscopy and the effect on the duration of the procedure were also evaluated. Throughout the procedure, the active TENS group experienced a VAS pain score reduction ≥50% compared to the placebo TENS group (P<0.001) and the control group (P<0.001). On the five‐point Likert scale, there was also a significant reduction in pain score in the active TENS group compared to the placebo TENS and control groups (P=0.009). No significant differences were found between the study groups as to the bloating sensation and the duration of the procedure. We conclude that TENS can be used as a pain relief therapy in unsedated screening colonoscopy.     

经皮神经电刺激配合认知行为干预在老年冠心病合并高血压患者中的应用

目的探究经皮神经电刺激配合认知行为干预在老年冠心病合并高血压患者中的应用效果。方法采用便利抽样法,选择哈尔滨医科大学附属第二医院2017年5月—2019年5月收治的老年冠心病合并高血压患者90例为研究对象。采用随机数字表法将其分为对照组和观察组,每组各45例。对照组实施认知行为干预,观察组实施经皮神经电刺激配合认知行为干预,比较两组患者的心绞痛症状控制、血压控制情况,采用自我感受负担量表(SPBS)比较两组患者自我感受负担。结果干预后观察组心绞痛控制有效率高于对照组,差异有统计学意义(P<0.05)。干预后观察组舒张压和收缩压均低于对照组,差异有统计学意义(P<0.05)。干预后对照组患者SPBS评分高于观察组,差异有统计学意义(P<0.001)。结论经皮神经电刺激配合认知行为干预应用于老年冠心病合并高血压患者中,有助于控制其心绞痛症状,降低血压,减轻自我感受负担。     

Effect of high frequency transcutaneous electrical nerve stimulation at root level menstrual pain in primary dysmenorrhea

IntroductionPrimary dysmenorrhea (PD) is a painful menstruation due to contractions in the uterus that induce ischemic pain associated with normal pelvic anatomy.ObjectiveThe purpose of the study is to evaluate the effect of High TENS application (root level) among adolescent girls of PD.Methodology140 adolescent girls were included with 14–19 years of age and randomly allocated into two groups of Experimental and Control group. The measurement of lower abdominal pain, referred low back pain, and referred bilateral thighs pain was performed by numerical pain rating scale and measurement of systolic as well as diastolic blood pressure by aneroid sphygmomanometer. The data collection was done before and after the intervention.Results & conclusionThere were highly significant difference in intragroup and intergroup comparison of all the outcome variables in group A (p value < 0.001). The study concluded that High frequency TENS application at root level show significant improvement for managing primary dysmenorrhea.     

Effects of electric stimulation on C and A delta fiber-mediated thermal perception thresholds

OBJECTIVE: To determine if interferential current (IFC) or transcutaneous electric nerve stimulation (TENS) alters C and A delta fiber-mediated thermal perception thresholds. DESIGN: Single-blind, randomized controlled trial. SETTING: Laboratory. PARTICIPANTS: One hundred forty healthy women volunteers (mean age +/- standard deviation, 20.6+/-2.7 y). INTERVENTIONS: Subjects were randomly and exclusively assigned to 1 of 7 groups (n=20 in each): 0, 5, and 100 Hz of IFC; 5 and 100 Hz of TENS; placebo and control stimulation. Stimulation was applied through 2 electrodes placed over the median nerve. Warm sensation, cold sensation, hot pain, and cold pain perception thresholds were measured from the thenar eminence by using a quantitative sensory testing device and a method of limits algorithm. MAIN OUTCOME MEASURES: Warm sensation, cold sensation, hot pain, and cold pain thresholds (degrees C) before, during, and after stimulation. RESULTS: There was a statistically significant effect of time for all 4 thermal perception thresholds (separate 2-way analyses of variance with repeated measures, all P<.001). There were no statistically significant differences between experimental groups, nor any interaction effects (all P>.05). CONCLUSIONS: Neither IFC nor TENS altered C and A delta fiber-mediated thermal perception thresholds. The results suggest that any analgesic mechanisms with these modalities are likely to be complex.     

Cholecystokinin receptors mediate tolerance to the analgesic effect of TENS in arthritic rats

Transcutaneous electrical nerve stimulation (TENS) is a treatment for pain that involves placement of electrical stimulation through the skin for pain relief. Previous work from our laboratory shows that repeated application of TENS produces analgesic tolerance by the fourth day and a concomitant cross-tolerance at spinal opioid receptors. Prior pharmacological studies show that blockade of cholecystokinin (CCK) receptors systemically and spinally prevents the development of analgesic tolerance to repeated doses of opioid agonists. We therefore hypothesized that systemic and intrathecal blockade of CCK receptors would prevent the development of analgesic tolerance to TENS, and cross-tolerance at spinal opioid receptors. In animals with knee joint inflammation (3% kaolin/carrageenan), high (100 Hz) or low frequency (4 Hz) TENS was applied daily and the mechanical withdrawal thresholds of the muscle and paw were examined. We tested thresholds before and after inflammation, and before and after TENS. Animals treated systemically, prior to TENS, with the CCK antagonist, proglumide, did not develop tolerance to repeated application of TENS on the fourth day. Spinal blockade of CCK-A or CCK-B receptors blocked the development of tolerance to high and low frequency TENS, respectively. In the same animals we show that spinal blockade of CCK-A receptors prevents cross-tolerance at spinal delta-opioid receptors that normally occurs with high frequency TENS; and blockade of CCK-B receptors prevents cross-tolerance at spinal mu-opioid receptors that normally occurs with low frequency TENS. Thus, we conclude that blockade of CCK receptors prevents the development of analgesic tolerance to repeated application of TENS in a frequency-dependent manner.     

Comparison of the analgesic efficacy of interferential therapy and transcutaneous electrical nerve stimulation

Objective

To compare the analgesic efficacy of interferential therapy (IFT) and transcutaneous electrical nerve stimulation (TENS) using an experimental cold pain model.

Design

Randomised controlled trial with repeated measures design.

Setting

University research laboratory.

Participants

Twenty healthy subjects.

Interventions

IFT and TENS applied to each subject on different days.

Main outcome measures

Cold pain threshold (time), intensity and unpleasantness (visual analogue scales).

Results

The mean cold pain threshold with a TENS intervention was higher than that with IFT. A training effect was evident as subjects’ responses become more consistent with repeated exposure to stimulation and the testing procedure. Using data from the second testing sessions, the differences in pain threshold between IFT and TENS for the two during-intervention (T3 and T4) measures were statistically significant (T3 difference in the means 5.9 seconds, 99% confidence interval 3.1 to 8.7 seconds; T4 difference in the means 6.6 seconds, 99% confidence interval 3.8 to 9.4 seconds). No significant differences were identified in pain intensity and unpleasantness ratings.

Conclusions

TENS is more effective than IFT at increasing cold pain thresholds in healthy subjects, and this effect increases with repeated exposures. Future trials should include a familiarisation session prior to testing to increase the consistency of subjects’ responses. The clinical implications of these effects need investigation.     

Effects of burst-type transcutaneous electrical nerve stimulation on cervical range of motion and latent myofascial trigger point pain sensitivity

Rodríguez-Fernández AL, Garrido-Santofimia V, Güeita-Rodríguez J, Fernández-de-las-Peñas C. Effects of burst-type transcutaneous electrical nerve stimulation on cervical range of motion and latent myofascial trigger point pain sensitivity.

Objective

To assess the effects of a burst application of transcutaneous electrical nerve stimulation (TENS) on cervical range of motion and pressure point sensitivity of latent myofascial trigger points (MTrPs).

Design

A single-session, single-blind randomized trial.

Setting

General community rehabilitation clinic.

Participants

Individuals (N=76; 45 men, 31 women) aged 18 to 41 years (mean ± SD, 23±4y) with latent MTrPs in 1 upper trapezius muscle.

Interventions

Subjects were randomly divided into 2 groups: a TENS group that received a burst-type TENS (pulse width, 200μs; frequency, 100Hz; burst frequency, 2Hz) stimulation over the upper trapezius for 10 minutes, and a placebo group that received a sham-TENS application over the upper trapezius also for 10 minutes.

Main Outcome Measures

Referred pressure pain threshold (RPPT) over the MTrP and cervical range of motion in rotation were assessed before, and 1 and 5 minutes after the intervention by an assessor blinded to subjects' treatment.

Results

The analysis of covariance revealed a significant group × time interaction (P<.001) for RPPT: the TENS group exhibited a greater increase compared with the control group; however, between-group differences were small at 1 minute (0.3kg/cm²; 95% confidence interval [CI], 0.1–0.4) and at 5 minutes (0.6kg/cm²; 95% CI, 0.3–0.8) after treatment. A significant group × time interaction (P=.01) was also found for cervical rotation in favor of the TENS group. Between-group differences were also small at 1 minute (2.0°; 95% CI, 1.0–2.8) and at 5 minutes (2.7°; 95% CI, 1.7–3.8) after treatment.

Conclusions

A 10-minute application of burst-type TENS increases in a small but statistically significant manner the RPPT over upper trapezius latent MTrPs and the ipsilateral cervical range of motion.     

综合康复治疗肩周炎的疗效观察

目的：观察口服普瑞巴林联合经皮电刺激治疗腹部带状疱疹后遗神经痛（PHN）的临床效果。方法：腹部PHN患者52例,随机分为2组各26例。对照组口服普瑞巴林300mg,每天2次;观察组在此基础上给予患处经皮神经电刺激（TENS）治疗。用视觉模拟疼痛评分（VAS）和睡眠质量评分（QS）评价效果,并观察治疗后的不良反应。结果：治疗1、2、3及4周后,2组VAS和QS评分均显著下降（均P〈0．05）,观察组降低较对照组更明显（均P〈0．05）。2组不良反应比较差异无统计学意义。结论：口服普瑞巴林300mg联合TENS治疗可有效缓解腹部PHN,改善睡眠质量。且无明显不良反应。     

Transcutaneous electrical nerve stimulation reduces pain,fatigue and hyperalgesia while restoring central inhibition in primary fibromyalgia

Because transcutaneous electrical nerve stimulation (TENS) works by reducing central excitability and activating central inhibition pathways, we tested the hypothesis that TENS would reduce pain and fatigue and improve function and hyperalgesia in people with fibromyalgia who have enhanced central excitability and reduced inhibition. The current study used a double-blinded randomized, placebo-controlled cross-over design to test the effects of a single treatment of TENS with people with fibromyalgia. Three treatments were assessed in random order: active TENS, placebo TENS and no TENS. The following measures were assessed before and after each TENS treatment: pain and fatigue at rest and in movement; pressure pain thresholds, 6-m walk test, range of motion; 5-time sit-to-stand test, and single-leg stance. Conditioned pain modulation was completed at the end of testing. There was a significant decrease in pain and fatigue with movement for active TENS compared to placebo and no TENS. Pressure pain thresholds increased at the site of TENS (spine) and outside the site of TENS (leg) when compared to placebo TENS or no TENS. During active TENS, conditioned pain modulation was significantly stronger compared to placebo TENS and no TENS. No changes in functional tasks were observed with TENS. Thus, the current study suggests TENS has short-term efficacy in relieving symptoms of fibromyalgia while the stimulator is active. Future clinical trials should examine the effects of repeated daily delivery of TENS, similar to the way in which TENS is used clinically on pain, fatigue, function, and quality of life in individuals with fibromyalgia.     

Outcome of transcutaneous electrical nerve stimulation in chronic pain: short-term results of a double-blind, randomised, placebo-controlled trial

The aim of this study was to test the efficacy of shortterm transcutaneous electrical nerve stimulation (TENS) treatment in chronic pain with respect to pain intensity and patients’ satisfaction with treatment results. We therefore performed a randomised controlled trial comparing TENS and sham TENS. Patients, researchers and therapists were blinded for treatment allocation. One hundred and sixty-three patients with chronic pain referred to the Pain Centre entered the study. Conventional TENS and sham TENS were applied in the segments of pain, for a period of ten days. Outcome measures were pain intensity (visual analogue scale) and patients’ satisfaction with treatment result (yes or no). The proportions of patients satisfied with treatment result differed significantly for TENS compared to sham TENS (58 and 42.7% respectively, x²=3.8, p=0.05). However, no differences in pain intensity were found for patients treated with TENS or sham TENS. Only for patients satisfied with treatment results pain intensity gradually decrease equally both for TENS and sham TENS with repeated treatment application.     

Efficacy of percutaneous and transcutaneous tibial nerve stimulation in women with idiopathic overactive bladder: A prospective randomised controlled trial

BackgroundDifferent studies have reported the efficacy of percutaneous tibial nerve stimulation (PTNS) and transcutaneous tibial nerve stimulation (TTNS) in treating idiopathic overactive bladder (OAB). However, no study has compared the effectiveness of PTNS and TTNS added to bladder training (BT) in idiopathic OAB.ObjectiveTo compare the efficacy of PTNS and TTNS added to BT in women with idiopathic OAB.MethodsWe randomised 60 women with idiopathic OAB into 3 groups. Group 1 (n = 19) received BT, Group 2 (n = 19) received PTNS in addition to BT, and Group 3 (n = 20) received TTNS in addition to BT. PTNS and TTNS were performed 2 days a week, for 30 min a day, for a total of 12 sessions for 6 weeks. Patients were evaluated by incontinence severity (pad test), a 3-day voiding diary (frequency of voiding, incontinence episodes, nocturia and number of pads used), symptom severity, quality of life, treatment success (positive response rate), treatment satisfaction (Likert scale), discomfort level and preparation time for stimulation (sec).ResultsAt the end of treatment; severity of incontinence, frequency of voiding, incontinence episodes, nocturia, number of pads used, symptom severity and quality of life were significantly improved in Groups 2 and 3 versus Group 1 (P < 0.0167). Treatment success and treatment satisfaction were higher in Groups 2 and 3 than Group 1 (P < 0.001 and P < 0.0167, respectively). Level of discomfort was lower, treatment satisfaction was higher and preparation time for stimulation was shorter in Group 3 than Group 2 (P < 0.05).ConclusionBoth the PTNS plus BT and TTNS plus BT were more effective than BT alone in women with idiopathic OAB. These 2 tibial nerve stimulation methods had similar clinical efficacy but with slight differences: TTNS had shorter preparation time, less discomfort level and higher patient satisfaction than PTNS.     

Effects of thermotherapy and transcutaneous electrical nerve stimulation on patients with primary dysmenorrhea: A randomized,placebo-controlled,double-blind clinical trial

ObjectivesTo evaluate the effects of thermotherapy and transcutaneous electrical nerve stimulation (TENS) on pain intensity, pressure pain threshold (PPT) and conditioned pain modulation (CPM) in patients with primary dysmenorrhea (PD).DesignA randomized, placebo-controlled, double-blind clinical trial.SettingPhysiotherapy Department of the Universidade Cidade de São Paulo, São Paulo (Brazil).InterventionsEighty-eight dysmenorrheic women were randomly allocated into four groups: Thermotherapy + TENS(n = 22), Thermotherapy(n = 22), TENS(n = 22) and Placebo(n = 22). Thermotherapy was applied by microwave diathermy (20 min), and TENS (200 μs, 100 Hz, 30 min), into the lower abdomen both.Main outcome measuresPain intensity was measured using the numeric rating scale (NRS) and the McGill Pain Questionnaire (Br-MPQ). PPT and CPM were recorded from women’s abdominal and lumbar. The evaluation was done in 5 times: baseline, after 20, 50, 110 min and 24 h from intervention.ResultsThere was a significant decrease in the NRS for Thermotherapy + TENS vs. TENS, for Thermotherapy vs. TENS and for Placebo, after 20 min; for Thermotherapy vs. TENS and for Placebo, after 110 min and 24 h. Abdome PPT increased in the Thermotherapy + TENS vs. TENS and Placebo, after 50 min; for Thermotherapy + TENS vs. Placebo and for Thermotherapy vs. Placebo, after 110 min. No changes in lumbar PPT and CPM were observed.ConclusionsThe use of thermotherapy reduced NRS compared to the TENS and Placebo after 20, 110 min and 24 h. Thermotherapy demonstrated an increase in the PPT in the abdomen after 50 and 110 min and decreased the Br-MPQ scores after 110 min in patients with PD.     

Early transcutaneous electrical nerve stimulation reduces hyperalgesia and decreases activation of spinal glial cells in mice with neuropathic pain

Although transcutaneous electrical nerve stimulation (TENS) is widely used for the treatment of neuropathic pain, its effectiveness and mechanism of action in reducing neuropathic pain remain uncertain. We investigated the effects of early TENS (starting from the day after surgery) in mice with neuropathic pain, on hyperalgesia, glial cell activation, pain transmission neuron sensitization, expression of proinflammatory cytokines, and opioid receptors in the spinal dorsal horn. Following nerve injury, TENS and behavioral tests were performed every day. Immunohistochemical, immunoblot, and flow cytometric analysis of the lumbar spinal cord were performed after 8 days. Early TENS reduced mechanical and thermal hyperalgesia and decreased the activation of microglia and astrocytes (P < 0.05). In contrast, the application of TENS at 1 week (TENS-1w) or 2 weeks (TENS-2w) after injury was ineffective in reducing hyperalgesia (mechanical and thermal) or activation of microglia and astrocytes. Early TENS decreased p-p38 within microglia (P < 0.05), the expression levels of protein kinase C (PKC-γ), and phosphorylated anti-phospho-cyclic AMP response element-binding protein (p-CREB) in the superficial spinal dorsal horn neurons (P < 0.05), mitogen-activated protein (MAP) kinases, and proinflammatory cytokines, and increased the expression levels of opioid receptors (P < 0.05). The results suggested that the application of early TENS relieved hyperalgesia in our mouse model of neuropathic pain by inhibiting glial activation, MAP kinase activation, PKC-γ, and p-CREB expression, and proinflammatory cytokines expression, as well as maintenance of spinal opioid receptors. The findings indicate that TENS treatment is more effective when applied as early after nerve injury as possible.