Evaluation of TENS during screening flexible sigmoidoscopy. Feasibility study of Transcutaneous Electrical Nerve Stimulation (TENS) for cancer bone pain. TENS for children's procedural pain. A randomized controlled study on the effect of two different treatments (FREMS AND TENS) in myofascial pain syndrome. An evaluation of transcutaneous electrical nerve stimulation for pain relief in labour. Randomization is important in studies with pain outcomes: systematic review of transcutaneous electrical nerve stimulation in acute postoperative pain. A controlled trial of transcutaneous electrical nerve stimulation (TENS) and exercise for chronic low back pain. Use of transcutaneous electrical nerve stimulation for postoperative pain. Pain reducing effect of three types of transcutaneous electrical nerve stimulation in patients with chronic pain: a randomized crossover trial.
The expectation of pain is a statistically significant factor negatively affecting patient compliance with current screening flexible sigmoidoscopy recommendations. Numerous pain reduction modalities have been studied with limited success. Transcutaneous electrical nerve stimulation (TENS) has been used to treat pain of various origins. The purpose of this pilot study was to determine the efficacy of TENS in reducing discomfort experienced during screening flexible sigmoidoscopy.A double-blind study was conducted in which 90 subjects were randomized to receive TENS, sham TENS, or control (standard care). The same pulse frequency and intensity were used for all subjects in the TENS group. Subjects completed preprocedural and postprocedural questionnaires, and the endoscopist completed a postprocedural questionnaire. A slight, but statistically insignificant (p =.526) reduction in the mean pain score reported by the TENS group was noted when compared with the sham TENS and control groups (2.00, 2.27, and 2.23 respectively). In light of the fact that only one pulse frequency and intensity of the TENS intervention were used in this study, further study with this safe and cost-effective modality is warranted. This multicenter study assessed the feasibility of conducting a phase III trial of transcutaneous electrical nerve stimulation (TENS) in patients with cancer bone pain recruited from palliative care services. Eligible patients received active and placebo TENS for 1 hour at site of pain in a randomized crossover design; median interval between applications 3 days. Responses assessed at 30 and 60 minutes included numerical and verbal ratings of pain at rest and on movement, and pain relief. Recruitment, tolerability, adverse events, and effectiveness of blinding were also evaluated. Twenty-four patients were randomised and 19 completed both applications. The intervention was well tolerated. Five patients withdrew: 3 due to deteriorating performance status, and 2 due to increased pain (1 each following active and placebo TENS). Confidence interval estimation around the differences in outcomes between active and placebo TENS suggests that TENS has the potential to decrease pain on movement more than pain on rest. Nine patients did not consider that a placebo was used; the remaining 10 correctly identified placebo TENS. Feasibility studies are important in palliative care prior to undertaking clinical trials. Our findings suggest that further work is required on recruitment strategies and refining the control arm before evaluating TENS in cancer bone pain.
                Cancer bone pain is common and severe, and partly mediated by hyperexcitability. Animal studies suggest that Transcutaneous Electrical Nerve Stimulation can reduce hyperalgesia. This study examined the feasibility of evaluating TENS in patients with cancer bone pain in order to optimize methods before a phase III trial.
                Copyright 2010 American Pain Society. Published by Elsevier Inc. All rights reserved. A 3 x 6 factorial design with a double blind and placebo control was employed to investigate the effect of TENS treatment on pain produced by venipuncture. The three treatment groups consisted of TENS, placebo-TENS and control. Subjects were blocked into six 2-year age groups (ages: 5-17 years). During the period of the study, 896 children attending the outpatient laboratory of a general hospital were screened and 514 children completed the study. The data which were collected before venipuncture included expected pain and state anxiety. Following venipuncture, pain intensity was measured with a vertical visual analogue scale (VAS) and pain affect was assessed with McGrath's faces scale. Significant main effects for treatment and age groups were obtained. Pain intensity and affect were lowest for the TENS group and highest for the control group. The pain scores were greatest for lower age groups and lowest for higher age groups. The results of this study support the use of TENS for children's pain and the need for interventions for children's procedural pain. Myofascial pain syndrome (MPS) is a frequent cause of chronic muscoloskeletal pain. Transcutaneous electrical nerve stimulation (TENS) is one of the most frequently employed treatments in MPS. The aim of this study is to compare the short and medium-term effects of frequency modulated neural stimulation (FREMS) to those of TENS in MPS.
                Forty subjects with upper trapezius MPS were randomly allocated to 1 of 2 groups, treated with either FREMS (n=19) or TENS (n=21). Each treatment consisted in 10 sessions lasting 20 min each. Patients were evaluated before treatment, at 1 week, and at 1 and 3 months after the end of treatment. Clinical evaluation included parameters for measurement of pain levels using the neck pain and disability visual analogue scale (NPDVAS) and algometry, evaluation of myofascial trigger point characteristics and measurement of the range of cervical movement (range of motion, ROM).
                The FREMS group showed a significant improvement in the NPDVAS, algometry, in myofascial trigger point characteristics, and in the ROM (homolateral rotation, controlateral rotation, bending and extension) after the end of treatment and at 1 and 3 months follow-up evaluation. The TENS group showed significant improvement in the same outcome measures except for algometry and cervical extension, but these improvements were maintained only at the 1 month follow-up evaluation. However, were not observed statistically significant differences between FREMS of TENS in many of outcome measures.
                Both FREMS and TENS have positive short-term effects on MPS. But, medium-term effects were achieved only with FREMS. The effectiveness of transcutaneous nerve stimulation (TENS) for pain relief in labour was evaluated by randomizing 280 patients in early labour into 2 groups. Inoperative sham machines were applied to patients in the control group and active units to those in the test group. Neither patients nor attending labour ward staff were aware of which group the patient was in. The intensity of low back pain and abdominal pain was assessed by the patient each hour on a visual analogue pain scale. Each patient served as her own control by switching off the machine for 2 contractions every hour and then recording the intensity of pain. The amount of conventional analgesia each patient received was recorded by labour ward staff. There was no difference in the intensity of pain recorded by each group. Nor was there any difference between the 2 groups in the change of pain experienced when the machine was switched off. Moreover there was no difference in the amount of other analgesia required. Some differences were found when those with little low back pain were excluded from the study. We conclude that TENS is ineffective as a routine method of pain relief in labour. It is likely to benefit only those with severe back pain and then only to a modest degree. We set out to examine the evidence for the importance of randomization of transcutaneous electrical nerve stimulation (TENS) in acute postoperative pain. Controlled studies were sought; randomization and analgesic and adverse effect outcomes were summarized. Forty-six reports were identified by searching strategies. Seventeen reports with 786 patients could be regarded unequivocally as randomized controlled trials (RCT) in acute postoperative pain. No meta-analysis was possible. In 15 of 17 RCT, we judged there to be no benefit of TENS compared with placebo. Of the 29 excluded trials, 19 had pain outcomes but were not RCT; in 17 of these 19 TENS studies, the authors concluded that TENS had a positive analgesic effect. No adverse effects were reported. Non-randomized studies overestimated treatment effects. A number of treatments are widely prescribed for chronic back pain, but few have been rigorously evaluated. We examined the effectiveness of transcutaneous electrical nerve stimulation (TENS), a program of stretching exercises, or a combination of both for low back pain. Patients with chronic low back pain (median duration, 4.1 years) were randomly assigned to receive daily treatment with TENS (n = 36), sham TENS (n = 36), TENS plus a program of exercises (n = 37), or sham TENS plus exercises (n = 36). After one month no clinically or statistically significant treatment effect of TENS was found on any of 11 indicators of outcome measuring pain, function, and back flexion; there was no interactive effect of TENS with exercise. Overall improvement in pain indicators was 47 percent with TENS and 42 percent with sham TENS (P not significant). The 95 percent confidence intervals for group differences excluded a major clinical benefit of TENS for most outcomes. By contrast, after one month patients in the exercise groups had significant improvement in self-rated pain scores, reduction in the frequency of pain, and greater levels of activity as compared with patients in the groups that did not exercise. The mean reported improvement in pain scores was 52 percent in the exercise groups and 37 percent in the nonexercise groups (P = 0.02). Two months after the active intervention, however, most patients had discontinued the exercises, and the initial improvements were gone. We conclude that for patients with chronic low back pain, treatment with TENS is no more effective than treatment with a placebo, and TENS adds no apparent benefit to that of exercise alone. This study examined the effects of transcutaneous electrical nerve stimulation (TENS) on incisional pain caused by the procedure of cleaning and packing an abdominal surgical wound. Seventy-five subjects (mean age 56.9 years) were randomly assigned to one of three intervention groups: TENS, placebo-TENS, or no-treatment control. The appropriate experimental treatment was administered during the routine dressing change which took place two mornings after surgery. Using an 11-point, visual analogue pain scale, subjects described pain experienced during the dressing change. Subjects who received TENS reported a significantly lower level of pain after dressing change than did those subjects who received either placebo-TENS or no-treatment. Drug administration variables did not contribute significantly to level of reported pain. 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.
Since the last version of this review, new relevant studies have not provided additional information to change the conclusions. Published literature on the subject lacks the methodological rigour or robust reporting needed to make confident assessments of the role of TENS in chronic pain management. Large multi-centre RCTs of TENS in chronic pain are still needed.