High-intensity Transcutaneous Electrical Nerve Stimulation Research Articles

High-frequency, high-intensity transcutaneous electrical nerve stimulation compared with opioids for pain relief after gynecological surgery: a systematic review and meta-analysis.

Opioids are important for postoperative analgesia but their use can be associated with numerous side effects. Transcutaneous electrical nerve stimulation (TENS) has been used for acute pain treatment and has dose-dependent analgesic effects, and therefore presents an alternative to intravenous (iv) opioids for postoperative pain relief. The aim of this meta-analysis was to compare high-frequency, high-intensity (HFHI or intense) TENS to iv opioids with regard to postoperative pain intensity, recovery time in the Post Anesthesia Care Unit (PACU) and opioid consumption after elective gynecological surgery. We searched Medline, Embase, Web of Science, Cochrane, Amed and Cinahl for RCTs and quasi-experimental studies (2010-2022), and WHO and ClinicalTrials.gov for ongoing/unpublished studies. Meta-analysis and subsequent Trial Sequential Analysis (TSA) was performed for all stated outcomes. Quality of evidence was assessed according to GRADE. Only three RCTs met the inclusion criteria (362 participants). The surgical procedures involved surgical abortion, gynecologic laparoscopy and hysteroscopy. The applied TENS frequency was 80 Hz and intensity 40-60 mA. There was no difference in pain intensity according to Visual Analogue Scale (VAS) at discharge from PACU between the TENS and opioid group (MD VAS-0.15, 95 % CI-0.38 to 0.09) (moderate level of evidence). Time in PACU was significantly shorter in the TENS group (MD-15.2, 95 %-22.75 to-7.67), and this finding was manifested by TSA (high-level of evidence). Opioid consumption in PACU was lower in the TENS group (MD Morphine equivalents per patient mg-3.42, 95 %-4.67 to-2.17) (high-level of evidence). There was no detectable difference in postoperative pain relief between HFHI TENS and iv opioids after gynecological surgery. Moreover, HFHI TENS decreases recovery time and opioid consumption in PACU. HFHI TENS may be considered an opioid-sparing alternative for postoperative pain relief after gynecological surgery. PROSPERO CRD42021231048.

High intensity-transcutaneous electrical nerve stimulation does not inhibit temporal summation of the nociceptive flexion reflex

Pain facilitation contributes to chronic pain conditions. Transcutaneous electrical nerve stimulation (TENS) is used to alleviate pain. The effects of conventional TENS on chronic pain have been limited, and its effects on pain facilitation are controversial. Because the analgesic effects of TENS depend on the setting parameters (e.g., pulse intensities or treatment time), the optimal TENS settings to maximize analgesic effects under various pain conditions have been investigated. High-intensity TENS (HI-TENS), which involves tolerable-level pulse intensities for a short duration, is another conventional TENS method that used to alleviate pain. However, the effects of HI-TENS on pain facilitation remain unclear. The temporal summation of pain is widely used to evaluate pain facilitation, and the temporal summation-nociceptive flexion reflex (TS-NFR) is a neuropsychological parameter that can be used to evaluate pain facilitation. We aimed to investigate the effects of HI-TENS on the TS-NFR in healthy participants. Participants were randomly allocated into HI-TENS (n = 15) and control groups (n = 16). HI-TENS was administered at the left lateral lower leg for 1 min. The TS-NFR elicited by three noxious stimuluses at the left sural nerve was obtained from electromyography of the left biceps femoris. The nociceptive flexion reflex (NFR) was obtained by a single noxious stimulus. We measured the thresholds of the NFR and the TS-NFR at baseline and post-intervention. The application of HI-TENS significantly increased the NFR threshold (p = 0.013) but not the TS-NFR threshold (p > 0.05). These results suggest that HI-TENS does not inhibit pain facilitation.

Transcutaneous Electrical Nerve Stimulation for Pain Management of Aspiration Abortion up to 83 Days of Gestation: A Randomized Controlled Trial.

To evaluate high-frequency, high-intensity transcutaneous electrical nerve stimulation (TENS) as an inexpensive, noninvasive pain management approach for first-trimester aspiration abortion. We conducted a noninferiority, single-blind, randomized controlled trial of patients seeking aspiration abortion at up to 83 days of gestation. Participants received TENS (placed posteriorly, T10-L1 and S2-S4) or intravenous (IV) sedation (fentanyl, midazolam). The primary outcome was pain with aspiration, as self-reported by visual analog scale (VAS, 100 mm). To detect at least a 15 mm mean difference on the 100 mm VAS with 90% power and a significance level of .05, a total of 90 participants were required. Between January 2018 and October 2019, we enrolled 109 participants (55 TENS, 54 IV). Participant median gestation was 53 days (range 36-82) in the TENS group and 58 days (range 35-82) in the IV group (P=.65). Group demographics and clinical histories were similar. Intention-to-treat analysis (n=109) yielded noninferior results for the primary outcome (mean difference 4.8 mm, 95% CI -5.9 to 13.5 mm). In the per-protocol analysis, 9 (16%) in the TENS group were excluded after receiving IV sedation; 100 participants were included (46 TENS, 54 IV). Median (range) reported VAS for aspiration was 73 mm (13-97) and 66 mm (0-99) in the TENS and IV groups, respectively (P=.40). With a mean difference of 4.4 mm (95% CI -5.6 to 14.5 mm), we found TENS to be noninferior to IV. Physicians underestimated participant pain, perceiving pain to be 34 mm (6-91) in the TENS group and 25 mm (0-83) in the IV group (P=.003). We found TENS to be a noninferior alternative to IV sedation for aspiration pain during first-trimester abortion. Expanding pain management options can improve quality of and access to abortion. Transcutaneous electrical nerve stimulation could be a standalone or adjunct approach for abortion pain management for those without access to or are ineligible to receive IV sedation due to the lack of sedation practitioner, designated driver, or local restrictions. ClinicalTrials.gov, NCT03187002.

Effects of high-frequency, high-intensity transcutaneous electrical nerve stimulation versus intravenous opioids for pain relief after hysteroscopy: a randomized controlled study.

ObjectiveTo compare the time spent in the Post-Anesthesia Care Unit (PACU) and the pain-relieving effects of treatment with high-frequency, high-intensity transcutaneous electrical nerve stimulation (TENS) or intravenous (IV) opioids after hysteroscopy.MethodsAll patients who postoperatively reported a visual analogue scale (VAS) pain score of ≥3 were included in the study. TENS treatment was given with a stimulus intensity between 40 and 60 mA for 1 minute and repeated once if there was insufficient pain relief. In the opioid group, a fractionated dose of 5 mg morphine was administered. If the patient reported insufficient pain relief after the assigned treatment, the patient was reassigned to the other treatment group.ResultsSeventy-four women were randomized to TENS (n=38) or IV opioids (n=36) for treatment. Both groups reported significant pain relief after discharge from the PACU, with a decrease of VAS scores from 5.6 to 1.4 in the TENS group (P<0.001) and 5.1 to 1.3 in the opioid group (P<0.001). There were no significant differences between the groups. When only the responders in both groups, i.e., patients with VAS scores of <3 on respectively assigned treatments, were compared, the TENS responders (n=22) were found to have spent a significantly shorter time in the PACU (91 vs. 69 minutes, P=0.013) compared to the opioid responders (n=20).ConclusionUsing TENS as first line of pain relief may reduce the need for postoperative opioids. In addition, TENS appears preferable as the first line of treatment due to its association with a shorter time spent in the PACU if the patient responds to the treatment.Trial RegistrationVästra Götalandsregionen Identifier: 211261

Transcutaneous electrical nerve stimulation (TENS) for pain control during first-trimester abortion: A single-blinded randomized controlled trial

Introduction High-frequency, high-intensity transcutaneous electrical nerve stimulation (TENS), pulsating electrical currents that activate underlying nerves, is an inexpensive and non-invasive pain control approach. We sought to compare TENS to intravenous sedation (IV) for pain control in first-trimester surgical abortion. Method We conducted a non-inferiority, single-blinded, randomized controlled trial of participants undergoing surgical abortion up to 11 weeks’ gestation. Participants received TENS (electrodes parallel to the spinal cord at the T10-L1 and S2-S4 levels) or IV (100mcg fentanyl and 1mg versed). Providers administered the IV sedation and research staff administered the TENS and were therefore not blinded. The primary outcome was self-reported pain with aspiration (visual analogue scale, VAS 100mm, 0 “no pain” and 100 “worst pain imaginable”). Non-inferiority limit was defined as 15mm. We also assessed participant demographics and blinding. Results A total of 109 participants were enrolled (55 TENS, 54 IV) between January 2018 and October 2019. Participants had a mean gestational age of 56-days across groups (p = 0.88); groups were similar with regard to age, race and ethnicity, parity, and BMI. Nine (16%) in the TENS group were given IV sedation and excluded from the per-protocol analysis. 100 participants were included in the per-protocol analysis (46 TENS, 54 IV). Mean reported VAS for aspiration was 64.78 mm (SD24.16) and 60.35mm (SD26.06) in the TENS and IV groups, respectively, with a mean difference of 4.43mm (95% CI −5.6 to 14.47). One IV group participant received additional IV medications (2%). Post-procedure, in both groups the majority of participants identified their correct assignment (p = 0.96); one in five in both groups incorrectly identified their assignment (21.7%, n = 10 TENS; 22.2%, n = 12 IV). Intention-to-treat analysis (n = 109) yielded non-inferior results for the primary outcome. Conclusions TENS for pain control during first-trimester surgical abortion is non-inferior to IV sedation with respect to the primary outcome of pain with aspiration. TENS could be a pain control option for patients without access to IV sedation or for those who are ineligible to receive IV sedation due to additional cost, lack of sedation provider or restrictions, including the need for a designated driver. Expanding pain control options improves quality of care and access to abortion.

Effects of high-frequency, high-intensity transcutaneous electrical nerve stimulation versus intravenous opioids for pain relief after gynecologic laparoscopic surgery: a randomized controlled study.

BackgroundThe aim of the study was to compare the pain relieving effect and the time spent in the recovery unit after treatment with high frequency, high-intensity transcutaneous electrical nerve stimulation (TENS) or intravenous (IV) opioids after gynecologic laparoscopic surgery.MethodsAll patients who postoperatively reported visual analogue scale (VAS) pain score ≥ 3 were consecutively included in the study. The TENS treatment was given with a stimulus intensity between 40–60 mA during 1 minute, repeated once if insufficient pain relief. In the opioid group, a maximum dose of 10 mg morphine was given IV. If the patient reported insufficient pain relief (VAS ≥ 3) on the assigned treatment, the patient crossed over to the other treatment group.ResultsNinety-three women were randomized to TENS (n = 47) or IV opioids (n = 46). Both groups reported significant pain relief at leave from the recovery unit (TENS group: VAS 5.4 to 1.0, P < 0.001; IV opioid group: VAS 5.2 to 1.1, P < 0.001) with no differences between the groups. When only responders, i.e. patients with VAS < 3 after assigned treatment, were compared the TENS responders spent significantly shorter time in the recovery unit (90 vs. 122 minutes, P = 0.008) compared to the responders in the opioid group.ConclusionsTENS and IV opioids are both effective treatments for pain relief after gynecologic laparoscopic surgery. TENS seems to be preferable for first choice of treatment as the treatment is associated with shorter time spent in recovery unit if the patient responds to the treatment.

Transcutaneous Nerve Stimulation for Pain Relief During Office Hysteroscopy: A Randomized Controlled Trial.

To evaluate the pain-relieving effect of transcutaneous electrical nerve stimulation (TENS) during office-based hysteroscopy without sedation. We conducted a randomized, double-blind, placebo-controlled trial. Participants were randomly assigned to the active TENS, placebo TENS, or control group. The active TENS intervention consisted of a varying high-frequency (80-100 Hz), 400-microseconds, individually adjusted, high-intensity TENS application with two self-adhesive electrodes placed parallel to the spinal cord at the T10-L1 and S2-S4 levels. In the placebo group, participants were connected to the TENS unit but delivering no electrical stimulation. The primary outcome was self-reported pain intensity (0-100 mm) measured on a visual analog scale at several stages (entry, contact, biopsy, and residual). The minimum clinically relevant difference for the visual analog scale has been previously reported as 10 mm. Sample size was calculated to provide 80% power to show a 10-mm difference (α=0.0125) in the primary outcome. Secondary outcomes included duration of the procedure, vital parameters, vasovagal symptoms, and participant satisfaction index (0-10 rating scale). A total of 138 women (46 per group) participated in the study between January 2016 and April 2016. No differences were found between groups regarding age, weight, body mass index, parity status, menopausal status, or previous hysteroscopy status. Visual analog scale scores highlighted a decrease in pain in the active TENS group compared with the placebo group (entry: -11 mm, 95% confidence interval [CI] -17 to -5; contact: -21.9 mm, 95% CI -30 to -13.9; biopsy: -30.5 mm, 95% CI -47.1 to -13.8, P<.001). Moreover, the reduction in pain reached the minimum clinically relevant difference. Regarding satisfaction, results also revealed differences between active TENS and placebo groups (1.3, 95% CI 0.5-2.2, P=.001). Transcutaneous electrical nerve stimulation reduces pain and increases patient satisfaction during office hysteroscopy without sedation. ClinicalTrials.gov, www.clinicaltrials.gov, NCT02647008.

Age Group Comparisons of TENS Response Among Individuals With Chronic Axial Low Back Pain

Chronic low back pain (CLBP) is a highly prevalent and disabling musculoskeletal pain condition among older adults. Transcutaneous electrical nerve stimulation (TENS) is commonly used to treat CLBP, however response to TENS in older adults compared with younger adults is untested. In a dose-response study stratified by age, 60 participants with axial CLBP (20 young, 20 middle-aged, 20 older) received four 20-minute sessions of high-frequency high-intensity TENS over a 2- to 3-week period in a laboratory-controlled setting. Experimental measures of pain sensitivity (mechanical pressure pain detection threshold) and central pain excitability (phasic heat temporal summation and heat aftersensations) were assessed before and after TENS. Episodic or immediate axial CLBP relief was assessed after TENS via measures of resting pain, movement-evoked-pain, and self-reported disability. Cumulative or prolonged axial CLBP relief was assessed by comparing daily pain reports across sessions. Independent of age, individuals experienced episodic increase in the pressure pain detection threshold and reduction in aftersensation after TENS application. Similarly, all groups, on average, experienced episodic axial CLBP relief via improved resting pain, movement-evoked pain, and disability report. Under this design, no cumulative effect was observed as daily pain did not improve for any age group across the 4 sessions. However, older adults received higher TENS amplitude across all sessions to achieve TENS responses similar to those in younger adults. These findings suggest that older adults experience similar episodic axial CLBP relief to that of younger individuals after high-frequency, high-intensity TENS when higher dose parameters are used. PerspectiveThis study examined age group differences in experimental and axial CLBP response to TENS, delivered under the current recommended parameters of strong, but tolerable amplitude. Older adults had comparable TENS response although at higher TENS amplitude than younger adults, which may have important mechanistic and clinical implications.

The excellent pain-relief effect of high-intensity transcutaneous electrical nerve stimulation (TENS) revealed by subjective and objective indicators

absence of control. Two physiotherapists carried out tests and retests and scored the child in the live situation as well as on the basis of video recordings. Wilcoxon Signed-Rank Test, ICC [2,1] and a descriptive measure for absolute reliability were used in the statistical analyses. Results: No systematic differences were found in scores between tests and retests with the exception of one rater’s reactive scores. All ICC values were excellent (ICC≥ 0.9) with the exception of one rater’s reactive scores. Complete agreements were seen in 73% of all scores between raters, days or between live versus video. In themajority of cases the scores with disagreement showed an absolute difference corresponding to one SATCo level for static, active and reactive scores respectively. Conclusion(s): This study shows that the relative reliability of the SATCo test is generally excellent. However, scores between raters, days or between live versus video differ by one or more levels in 27% of all separate analyses. This should be considered when using SATCo as a clinical outcome measure. Implications: SATCo is a relevant assessment tool with potential for implementation in clinical practise. Further refinements could increase the reliability of themeasure. This would increase the value of this test in research and in clinical practise.

Comparison of TENS treatments in hemiplegic shoulder pain

The aim of this paper is to evaluate the effectiveness of high-intensity versus low-intensity transcutaneous electrical nerve stimulation (TENS) and versus placebo for treatment of hemiplegic shoulder pain. Three groups of 20 patients each (A, B, C) were studied. In group A high-intensity TENS was delivered at 3 times the sensory threshold with frequency of 100 Hz; in group B low-intensity TENS was delivered at the sensory threshold with frequency of 100 Hz. Group C received placebo stimulation. The treatment protocol consisted of 12 sessions (4 weeks). Before treatment, at the end of it and one month after, passive range of motion (PROM) for flexion, extension, abduction and external rotation were evaluated. Statistically significant improvements of PROMs were recorded for group A, but not for groups B or C.

HI-TENS Reduces Moderate-to-Severe Pain Associated With Most Wound Care Procedures

This study systematically examined pain associated with wound care procedures (WCPs) and evaluated the effectiveness of high-intensity transcutaneous electrical nerve stimulation (HI-TENS) for reducing this pain in a two-phase design. Phase 1 (N = 57) examined patient, wound, and procedural factors, as well as analgesic intake, associated with WCPs. Pain during the WCPs was rated on a 0-10 numerical scale. Subjects reported a mean pain of 6.0 (standard deviation 3.04) during Phase 1, with 43 (75.4%) subjects experiencing moderate or severe pain (i.e., ≥4). Subjects who received opioid and/or nonopioid analgesia 1 hr before or during the WCPs (36.8%) reported significantly higher pain levels than those who had not received analgesia (p = .013). In Phase 2, 23 subjects with ≥4 pain during Phase 1 had HI-TENS applied to the area surrounding the wound during the WCPs. HI-TENS significantly reduced WCP pain by a mean of 2.0 (±2.31; effect size = 0.67; p = .001). This effect was significant for subjects with severe Phase 1 pain (i.e., ≥8; effect size = 1.00; p = .007) but not for subjects with moderate Phase 1 pain (i.e., 4-7; effect size = 0.40; p = .053). These findings demonstrate that pain during WCPs is a significant problem, that nurses appropriately administer analgesics but these are not sufficient, and that using HI-TENS may further reduce pain, particularly in patients experiencing severe WCP pain.

A comparison of high versus low intensity transcutaneous electrical nerve stimulation for chronic pain

Background and objectives: Over the last 35 years electrical nerve stimulation has been employed increasingly in the treatment of chronic pain. This study was carried out to compare the analgesic effect that produced by applying a fixed frequency (50 Hz) high intensity tolerably painful transcutaneous electrical nerve stimulation (TENS) with the conventional low intensity TENS. Methods: Thirty six patients (26 Females and 10 males with age 18 – 54 years) were selected from patients consulting a private psychiatric clinic in Erbil city from March 2009 to march 2010. They had chronic pain in head and neck for more than 2 years. The cases were allocated randomly into two groups; group A treated by the conventional TENS of high frequency 100 Hz with low intensity current, by applying the electrical electrodes on the nucheal region (back of neck) for 20 minutes once daily for six days, and once weekly for one month then follow up the patients after 3 months, while in group B; the same procedure was applied but with fixed frequency 50 Hz and high intensity current adjusted to a tolerably painful level. The pain measured by verbal scale ranged from 0 to 4. Results: Patients who received high intensity TENS; 94% of them got immediate pain relief and 17% got long lasting pain relief more than three months, while with the conventional TENS only 33% got immediate pain relief and no one got long lasting pain relief. Conclusion: The tolerably painful high intensity TENS gives better analgesic effect than the conventional TENS, and in some patients it may leads to long lasting analgesic effect(this may be attributed to the pan stimulation involving a variety of afferent fibers; Aa/β, Ad &amp; C).

High-frequency, high-intensity transcutaneous electrical nerve stimulation as treatment of pain after surgical abortion

The aim of the study was to compare the pain-relieving effect and the time spent in the recovery ward after treatment with high-frequency, high-intensity transcutaneous electrical nerve stimulation (TENS) or intravenous (IV) conventional pharmacological treatment after surgical abortion. Two-hundred women who underwent surgical abortion and postoperatively reported a visual analogue scale (VAS) pain score ⩾ 3 were included. The patients were randomised to TENS or conventional pharmacological treatment for their postoperative pain. The TENS treatment was given with a stimulus intensity between 20 and 60 mA during 1 min and repeated once if insufficient pain relief (VAS ⩾ 3) . In the conventional pharmacological treatment group, a maximum dose of 100 μg fentanyl was given IV. There was no difference between the groups with regard to pain relief according to the VAS pain score (TENS = VAS 1.3 vs. IV opioids = VAS 1.6; p = 0.09) upon discharge from the recovery ward. However, the patients in the TENS group spent shorter time (44 min) in the recovery ward than the conventional pharmacological treatment group (62 min; p < 0.0001). The number of patients who needed additional analgesics in the recovery ward was comparable in both groups, as was the reported VAS pain score upon leaving the hospital (TENS = 2.0 vs. conventional pharmacological treatment = 1.8, NS). These results suggest that the pain-relieving effect of TENS seems to be comparable to conventional pharmacological treatment with IV opioids. Hence, TENS may be a suitable alternative to conventional pain management with IV opioids after surgical abortion.

Does transcutaneous electrical nerve stimulation (TENS) produce 'dose-responses'? A review of systematic reviews on chronic pain

Background: This review aimed to examine existing systematic reviews regarding the clinical efficacy of transcutaneous electrical nerve stimulation (TENS) in reducing pain in patients with chronic pain conditions.Methods: Data concerning the methods and conclusions of the reviews and individual trials were extracted. The data from the individual trials were subcategorised according to the validity of outcome measures, methodological quality, sample size, and 'dose response' (if any) of TENS.Results: Two of the six reviews concerning TENS and chronic pain reported that high intensity TENS applications were more effective compared to placebo than low intensity applications. However, the reviews and the authors' conclusions were based on a total of eight high quality trials which reported positive findings on a visual analogue scale or numeric rating scale which measured pain relief/intensity.Discussion: Data from chronic pain trials that use these outcome measures show that any dose-related responses of TENS cannot be conclusively demonstrated as a result of the number of confounding variables (e.g. inadequate design, low statistical power and the many differences in TENS protocols such as repeated versus single treatments).Conclusion: To address these issues, recommendations are made for future systematic reviews and randomised controlled trials. Such recommendations include the need for more comprehensive and rigorous tools in assessing substantive trials within systematic reviews.

Pain reducing effect of three types of transcutaneous electrical nerve stimulation in patients with chronic pain: a randomized crossover trial

Transcutaneous electrical nerve stimulation (TENS) is a frequently applied therapy in chronic pain although evidence for effectiveness is inconclusive. Several types of TENS, based on different combinations of frequency, pulse duration and intensity, exist. The precise mechanism of action and the relevance of combinations of stimulus parameters are still unclear. To compare the effectiveness of three types of TENS we conducted a randomized, single blinded crossover trial. Patients received two times a 2-week period of daily TENS treatment, separated by a washout period of 2 weeks. In total, 180 chronic pain patients were randomized into three groups. In group 1, high frequency, low intensity TENS (HFT) was compared with high frequency, high intensity TENS (HIT). In groups 2 and 3, HFT and HIT were compared with a control TENS (COT). The order of applying the different modalities of TENS in each group was also randomized. Primary outcome was the patient's overall assessment of effectiveness and pain reduction (VAS). No differences were found in patient's assessment or pain reducing effect between the three groups, indicating no superiority of one type of TENS. In total, 56% continued TENS after the 2-week treatment period. At 6 months, 42% of all patients still used TENS. We concluded that there were no differences in effectiveness for the three types of TENS used in this study. Because no placebo group was included, no definite conclusions on effectiveness of TENS in general in the treatment of chronic pain could be made.

A comparative study of the effect of high-intensity transcutaneous nerve stimulation and oral naproxen on intrauterine pressure and menstrual pain in patients with primary dysmenorrhea

OBJECTIVE: Our purpose was to compare the effects of high-intensity transcutaneous electrical nerve stimulation and oral naproxen (500 mg) on intrauterine pressure and menstrual pain. STUDY DESIGN: An open, randomized crossover study was performed on 12 women with primary dysmenorrhea. Intrauterine pressure was recorded with a microtransducer catheter, and the pain score was assessed by a visual analog scale. RESULTS: Before treatment all patients displayed signs of uterine hyperactivity as judged by a high resting pressure (7.5 ± 0.4 kPa), high active pressure (24.0 ± 0.8 kPa), and a high frequency of pressure cycles (13.3 ± 0.5 contractions per 0.5 hour). Oral administration of naproxen suppressed (p < 0.01) all uterine activity parameters. Treatment with transcutaneous electrical nerve stimulation induced a prompt onset of pain relief in a strictly segmental manner, but there were no significant changes in uterine activity. The pain score was significantly reduced (p < 0.001) from 30 to 60 minutes after treatment with transcutaneous electrical nerve stimulation and from 19 to 120 minutes after naproxen administration. CONCLUSIONS: Treatment with transcutaneous electrical nerve stimulation induced a prompt onset of pain relief without any significant changes in uterine activity. Possible mechanisms for the pain relief, decreased uterine ischemia or decreased activity in the pain transmission system at spinal or supraspinal levels, are discussed. (AM J OBSTET GYNECOL 1994;170:123-9.)

A comparative study of the effect of high-intensity transcutaneous nerve stimulation and oral naproxen on intrauterine pressure and menstrual pain in patients with primary dysmenorrhea

<b>Objective:</b> Our purpose was to compare the effects of high-intensity transcutaneous electrical nerve stimulation and oral naproxen (500 mg) on intrauterine pressure and menstrual pain. <b>Study Design:</b> An open, randomized crossover study was performed on 12 women with primary dysmenorrhea. Intrauterine pressure was recorded with a microtransducer catheter, and the pain score was assessed by a visual analog scale. <b>Results:</b> Before treatment all patients displayed signs of uterine hyperactivity as judged by a high resting pressure (7.5 ± 0.4 kPa), high active pressure (24.0 ± 0.8 kPa), and a high frequency of pressure cycles (13.3 ± 0.5 contractions per 0.5 hour). Oral administration of naproxen suppressed (<i>p</i> < 0.01) all uterine activity parameters. Treatment with transcutaneous electrical nerve stimulation induced a prompt onset of pain relief in a strictly segmental manner, but there were no significant changes in uterine activity. The pain score was significantly reduced (<i>p</i> < 0.001) from 30 to 60 minutes after treatment with transcutaneous electrical nerve stimulation and from 19 to 120 minutes after naproxen administration. <b>Conclusions:</b> Treatment with transcutaneous electrical nerve stimulation induced a prompt onset of pain relief without any significant changes in uterine activity. Possible mechanisms for the pain relief, decreased uterine ischemia or decreased activity in the pain transmission system at spinal or supraspinal levels, are discussed.

Effects of transcutaneous electrical nerve stimulation on myofascial pain and trigger point sensitivity

The effects of transcutaneous electrical nerve stimulation (TENS) on myofascial pain and trigger point sensitivity were assessed. Four modes of TENS and a no-stimulation control were compared in a double-blind design. Stimulation, carried out for 10 min on 60 subjects (12/group), showed significant pain reductions with 100 Hz, 250 msec stimulation followed by 100 Hz, 50 msec and then pain suppressor TENS. No pain reductions were found in the 2 Hz, 250 msec TENS or the control. No significant alteration in myofascial trigger point sensitivity, assessed with the pressure algometer, was found between the groups. The results suggest that high frequency, high intensity TENS is effective in reducing myofascial pain, and that these pain reductions do not reflect changes in local trigger point sensitivity.