Comparison of percutaneous electrical nerve stimulation with transcutaneous electrical nerve stimulation for long-term pain relief in patients with chronic low back pain

Do Electrical Stimulation Devices Reduce Pain and Improve Function?-A Comparative Review

BACKGROUND

Multiple forms of electrical stimulation (ES) potentially offer widely varying clinical benefits. Diminished function commonly associated with acute and chronic pain lessens productivity and increases medical costs. This review aims to compare the relative effects of various forms of ES on functional and pain outcomes.

METHODS

A comprehensive literature search focused on studies of commonly marketed forms of ES used for treatment of pain and improvement of function. Peer-reviewed manuscripts were categorized as "Important" (systematic review or meta-analysis, randomized controlled trial, observational cohort study) and "Minor" (retrospective case series, case report, opinion review) for each identified form of ES.

RESULTS AND DISCUSSION

Varying forms of ES have markedly different technical parameters, applications, and indications, based on clinically meaningful impact on pain perception, function improvement, and medication reduction. Despite being around for decades, there is limited quality evidence for most forms of ES, although there are several notable exceptions for treatment of specific indications. Neuromuscular electrical stimulation (NMES) has well-demonstrated beneficial effects for rehabilitation of selective spinal cord injured (SCI), post-stroke, and debilitated inpatients. Functional electrical stimulation (FES) has similarly shown effectiveness in rehabilitation of some stroke, SCI, and foot drop outpatients. H-Wave® device stimulation (HWDS) has moderate supportive evidence for treatment of acute and refractory chronic pain, consistently demonstrating improvements in function and pain measures across diverse populations. Interestingly, transcutaneous electrical nerve stimulation (TENS), the most widely used form of ES, demonstrated insignificant or very low levels of pain and functional improvement.

CONCLUSION

Ten of 13 reviewed forms of ES have only limited quality evidence for clinically significant reduction of pain or improvement of function across different patient populations. NMES and FES have reasonably demonstrated effectiveness, albeit for specific clinical rehabilitation indications. HWDS was associated with the most clinically significant outcomes, in terms of functional improvement combined with reduction of pain and medication use. More rigorous long-term clinical trials are needed to further validate appropriate use and specific indications for most forms of ES.

LEVEL OF EVIDENCE

II.

Efficacy of Transcutaneous Tibial Nerve Stimulation With Silver Spike Point® Electrodes for Refractory Overactive Bladder: A Single-Arm Study

Background Tibial nerve stimulation therapy is a treatment option for an overactive bladder. A surface electrode called a Silver Spike Point® electrode, which does not directly puncture the skin as in transcutaneous tibial nerve stimulation, but is expected to exert the same therapeutic effect as percutaneous tibial nerve stimulation, was developed. This study investigated the efficacy and safety of tibial nerve stimulation with Silver Spike Point® electrodes for refractory overactive bladder. Methodology This was a six-week, single-arm, prospective study on the efficacy and safety of transcutaneous tibial nerve stimulation for patients with refractory overactive bladder. Each treatment lasted 30 minutes and was performed twice a week. The stimulation sites of the tibial nerve were the Sanyinjiao point (SP6) and Zhaohai point (KI6) in both legs. The primary endpoint was the change in the total overactive bladder symptom score. Results In total, 29 patients (20 males and nine females: 64.86 ± 17.98 years old) were included in this study. Two women dropped out; one because of an adverse event and the other as requested. Therefore, 27 patients completed the study. The total overactive bladder symptom and International Consultation on Incontinence Questionnaire-Short Form scores significantly decreased by 2.22 and 2.39 points, respectively (p < 0.01 each). In the frequency volume chart, the numbers of urgency episodes and leaks in 24 hours significantly decreased by 1.53 and 0.44, respectively (p = 0.02 each). Conclusions Transcutaneous tibial nerve stimulation therapy using Silver Spike Point® electrodes was useful for patients with refractory overactive bladder and, thus, has potential as a new treatment option for refractory overactive bladder.

Characterising the Features of 381 Clinical Studies Evaluating Transcutaneous Electrical Nerve Stimulation (TENS) for Pain Relief: A Secondary Analysis of the Meta-TENS Study to Improve Future Research

Background and Objectives: Characterising the features of methodologies, clinical attributes and intervention protocols, of studies is valuable to advise directions for research and practice. This article reports the findings of a secondary analysis of the features from studies screened as part of a large systematic review of TENS (the meta-TENS study). Materials and Methods: A descriptive analysis was performed on information associated with methodology, sample populations and intervention protocols from 381 randomised controlled trials (24,532 participants) evaluating TENS delivered at a strong comfortable intensity at the painful site in adults with pain, irrespective of diagnosis. Results: Studies were conducted in 43 countries commonly using parallel group design (n = 334) and one comparator group (n = 231). Mean ± standard deviation (SD) study sample size (64.05 ± 58.29 participants) and TENS group size (27.67 ± 21.90 participants) were small, with only 13 of 381 studies having 100 participants or more in the TENS group. Most TENS interventions were ‘high frequency’ (>10 pps, n = 276) and using 100 Hz (109/353 reports that stated a pulse frequency value). Of 476 comparator groups, 54.2% were active treatments (i.e., analgesic medication(s), exercise, manual therapies and electrophysical agents). Of 202 placebo comparator groups, 155 used a TENS device that did not deliver currents. At least 216 of 383 study groups were able to access other treatments whilst receiving TENS. Only 136 out of 381 reports included a statement about adverse events. Conclusions: Clinical studies on TENS are dominated by small parallel group evaluations of high frequency TENS that are often contaminated by concurrent treatment(s). Study reports tended focus on physiological and clinical implications rather than the veracity of methodology and findings. Previously published criteria for designing and reporting TENS studies were neglected and this should be corrected in future research using insights gleaned from this analysis.

Does TENS Reduce the Intensity of Acute and Chronic Pain? A Comprehensive Appraisal of the Characteristics and Outcomes of 169 Reviews and 49 Meta-Analyses

Background and Objectives: Uncertainty about the clinical efficacy of transcutaneous electric nerve stimulation (TENS) to alleviate pain spans half a century. There has been no attempt to synthesise the entire body of systematic review evidence. The aim of this comprehensive review was to critically appraise the characteristics and outcomes of systematic reviews evaluating the clinical efficacy of TENS for any type of acute and chronic pain in adults. Materials and Methods: We searched electronic databases for full reports of systematic reviews of studies, overviews of systematic reviews, and hybrid reviews that evaluated the efficacy of TENS for any type of clinical pain in adults. We screened reports against eligibility criteria and extracted data related to the characteristics and outcomes of the review, including effect size estimates. We conducted a descriptive analysis of extracted data. Results: We included 169 reviews consisting of eight overviews, seven hybrid reviews and 154 systematic reviews with 49 meta-analyses. A tally of authors' conclusions found a tendency toward benefits from TENS in 69/169 reviews, no benefits in 13/169 reviews, and inconclusive evidence in 87/169 reviews. Only three meta-analyses pooled sufficient data to have confidence in the effect size estimate (i.e., pooled analysis of >500 events). Lower pain intensity was found during TENS compared with control for chronic musculoskeletal pain and labour pain, and lower analgesic consumption was found post-surgery during TENS. The appraisal revealed repeated shortcomings in RCTs that have hindered confident judgements about efficacy, resulting in stagnation of evidence. Conclusions: Our appraisal reveals examples of meta-analyses with 'sufficient data' demonstrating benefit. There were no examples of meta-analyses with 'sufficient data' demonstrating no benefit. Therefore, we recommend that TENS should be considered as a treatment option. The considerable quantity of reviews with 'insufficient data' and meaningless findings have clouded the issue of efficacy. We offer solutions to these issues going forward.

Percutaneous Electrical Nerve Stimulation (PENS) as a Rehabilitation Approach for Reducing Mixed Chronic Pain in Patients with Musculoskeletal Disorders

“Mixed pain” is a term recently introduced to define the overlapping of nociceptive, neuropathic and nociplastic pain. To date, it has been reported that pharmacological treatments might have a modest effectiveness on patients affected by mixed chronic pain, with detrimental consequences in terms of disability, physical function and health-related quality of life. In this scenario, Percutaneous Electrical Nerve Stimulation (PENS), a mini-invasive neuromodulation technique, has been recently suggested as a promising approach for the complex management of mixed pain in musculoskeletal disorders. Albeit PENS showed to be effective in reducing unspecified pain in several chronic pain conditions, there is still a lack of evidence in the literature about its role in the management of neuropathic or mixed pain not responsive to pharmacological treatments. Therefore, by the present scoping review, we portray the potential effects of PENS in the multidisciplinary and multidimensional management of mixed chronic pain in patients with musculoskeletal disorders.

Effectiveness of percutaneous electrical nerve stimulation for musculoskeletal pain: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

To evaluate the effects of percutaneous electrical stimulation (PENS) alone or as an adjunct with other interventions on pain and related disability in musculoskeletal pain conditions.

DATABASES AND DATA TREATMENT

Search of MEDLINE, EMBASE, AMED, CINAHL, EBSCO, PubMed, PEDro, Cochrane Library, SCOPUS and Web of Science databases. Randomized controlled trials where at least one group received any form of PENS for musculoskeletal condition. Studies had to include humans and collect outcomes on pain and related disability in musculoskeletal pain. Risk of bias was assessed by the Cochrane Guidelines, the quality of evidence by using the GRADE approach. Standardized mean differences (SMD) were calculated.

RESULTS

Sixteen studies were included and included heterogeneous musculoskeletal conditions with short- or midterm follow-ups. PENS alone had a large effect (SMD -1.22, 95% CI -1.66 to -0.79) on pain and a small effect (SMD -0.33, 95% CI -0.61 to -0.06) on related disability at short-term as compared with sham. A moderate effect of PENS alone (SMD -0.71, 95% CI -1.23 to -0.19) on pain when compared with other interventions was observed. The inclusion of PENS with other interventions had a moderate effect for decreasing pain at short- (SMD -0.70, 95% CI -1.02 to -0.37) and midterm (SMD -0.68, 95% CI -1.10 to -0.27). No effect at midterm (SMD -0.21, 95% CI -0.52 to 0.10) on related disability was seen. The risk of bias was generally low; but the heterogenicity of the results downgraded the level of evidence.

CONCLUSION

There is low level of evidence suggesting the effects of PENS alone or in combination for pain, but not related disability, in musculoskeletal pain.

LEVEL OF EVIDENCE

Therapy, level 1a. Registration number: CRD42019131331.

SIGNIFICANCE

This meta-analysis investigating the effectiveness of PENS for the management of pain and related disability in musculoskeletal pain conditions found that PENS could decrease level of pain intensity but not relateddisability in musculoskeletal pain disorders.

Literature Review and Meta-Analysis of Transcutaneous Electrical Nerve Stimulation in Treating Chronic Back Pain

Supplemental digital content is available in the text.

Background and Objectives

This study is a meta-analysis of randomized controlled trials comparing the efficacy of transcutaneous electrical nerve stimulation (TENS) to a control and to other nerve stimulation therapies (NSTs) for the treatment of chronic back pain.

Methods

Citations were identified in MEDLINE, the Cochrane Library, Google Scholar, and ClinicalTrials.gov through June 2014 using the following keywords: nerve stimulation therapy, transcutaneous electrical nerve stimulation, back pain, chronic pain. Control treatments included sham, placebo, or medication only. Other NSTs included electroacupuncture, percutaneous electrical nerve stimulation, and percutaneous neuromodulation therapy.

Results

Twelve randomized controlled trials including 700 patients were included in the analysis. The efficacy of TENS was similar to that of control treatment for providing pain relief (standardized difference in means [SDM] = −0.20; 95% confidence interval [CI], −0.58 to 0.18; P = 0.293). Other types of NSTs were more effective than TENS in providing pain relief (SDM = 0.86; 95% CI, 0.15–1.57; P = 0.017). Transcutaneous electrical nerve stimulation was more effective than control treatment in improving functional disability only in patients with follow-up of less than 6 weeks (SDM = −1.24; 95% CI, −1.83 to −0.65; P < 0.001). There was no difference in functional disability outcomes between TENS and other NSTs.

Conclusions

These results suggest that TENS does not improve symptoms of lower back pain, but may offer short-term improvement of functional disability.

Use of electroanalgesia and laser therapies as alternatives to opioids for acute and chronic pain management

The use of opioid analgesics for postoperative pain management has contributed to the global opioid epidemic. It was recently reported that prescription opioid analgesic use often continued after major joint replacement surgery even though patients were no longer experiencing joint pain. The use of epidural local analgesia for perioperative pain management was not found to be protective against persistent opioid use in a large cohort of opioid-naïve patients undergoing abdominal surgery. In a retrospective study involving over 390,000 outpatients more than 66 years of age who underwent minor ambulatory surgery procedures, patients receiving a prescription opioid analgesic within 7 days of discharge were 44% more likely to continue using opioids 1 year after surgery. In a review of 11 million patients undergoing elective surgery from 2002 to 2011, both opioid overdoses and opioid dependence were found to be increasing over time. Opioid-dependent surgical patients were more likely to experience postoperative pulmonary complications, require longer hospital stays, and increase costs to the health-care system. The Centers for Disease Control and Prevention emphasized the importance of finding alternatives to opioid medication for treating pain. In the new clinical practice guidelines for back pain, the authors endorsed the use of non-pharmacologic therapies. However, one of the more widely used non-pharmacologic treatments for chronic pain (namely radiofrequency ablation therapy) was recently reported to have no clinical benefit. Therefore, this clinical commentary will review evidence in the peer-reviewed literature supporting the use of electroanalgesia and laser therapies for treating acute pain, cervical (neck) pain, low back pain, persistent post-surgical pain after spine surgery (“failed back syndrome”), major joint replacements, and abdominal surgery as well as other common chronic pain syndromes (for example, myofascial pain, peripheral neuropathic pain, fibromyalgia, degenerative joint disease/osteoarthritis, and migraine headaches).

Development and application of a newly designed massage instrument for deep cross-friction massage in chronic non-specific low back pain

Objective

To introduce a newly designed massage instrument, the Hand Grip T-bar (HT-bar) and use it to relieve chronic non-specific low back pain (nLBP) through deep cross-friction massage (roptrotherapy).

Method

22 subjects (9 males and 13 females, aged 51.6±6.7) with chronic nLBP were allocated randomly to a Roptrotherapy group (n=12) and a Transcutaneous Electrical Nerve Stimulation (TENS) group (n=10). The Roptrotherapy group received deep cross-friction massage with the HT-bar, which was made of metal and had a cylinder for increasing weight and grooves for an easy grip. It was applied across the middle and lower back for 20 minutes a day, 3 days a week for 2 weeks. The TENS group received TENS for 20 minutes a day, 5 days a week for 2 weeks. The outcome was measured on the pain numeric rating scale (PNRS), by the Oswestry disability index (ODI), and by the Roland & Morris Disability Questionnaire (RMDQ) at pre-treatment, at immediate post-treatment and 2 weeks later. The application of the HT-bar was assessed by a questionnaire to 19 therapists.

Results

At post-treatment, immediately and 2 weeks later, both groups showed significant improvement in PNRS, ODI and RMDQ. During the two weeks after post-treatment, however, the Roptrotherapy group improved in PNRS, ODI and RMDQ, but the TENS group did not. Over 80% of the therapists responded that the HT-bar was useful and comfortable.

Conclusion

This study suggests that deep cross-friction massage can be a beneficial therapeutic technique and that the HT-bar can be a useful instrument in deep cross-friction massage for chronic nLBP patients.

Mainstreaming Acupuncture: Barriers and Solutions

There is a place for the acupuncture profession within primary care. Nationwide, community clinics that serve the population of under- and uninsured persons are facing a tremendous shortage of primary care practitioners. Marginalized health care professions, that is, acupuncture, chiropractic, and naturopathy, are being drawn into a primary care role. An unanticipated workforce opportunity exists to fill the caregiver gap in community clinics. This transition can be quickly realized in states such as California where statutory code states that acupuncture is to be regulated and controlled as a primary care profession, but the requisite training has yet to be provided. Specific clinical experience in primary care settings would help overcome long-standing barriers that have resulted in the marginalization of the profession, high under- and unemployment among acupuncturists, and result in greater access to acupuncture treatment. A 1-year primary care training program for licensed acupuncturists (LAcs), which features clinical and didactic training, akin to what a physician assistant receives, would prepare acupuncturists to work in mainstream medicine. With appropriate training and biomedical collaboration skills, the participation of acupuncturists in mainstream medical settings can be accomplished with support from the acupuncture profession and mainstream medicine.

A systematic review on the effectiveness of physical and rehabilitation interventions for chronic non-specific low back pain. Eur Spine J. 2011;20:19-39. [PMID: 20640863 PMCID: PMC3036018 DOI: 10.1007/s00586-010-1518-3]

Low back pain (LBP) is a common and disabling disorder in western society. The management of LBP comprises a range of different intervention strategies including surgery, drug therapy, and non-medical interventions. The objective of the present study is to determine the effectiveness of physical and rehabilitation interventions (i.e. exercise therapy, back school, transcutaneous electrical nerve stimulation (TENS), low level laser therapy, education, massage, behavioural treatment, traction, multidisciplinary treatment, lumbar supports, and heat/cold therapy) for chronic LBP. The primary search was conducted in MEDLINE, EMBASE, CINAHL, CENTRAL, and PEDro up to 22 December 2008. Existing Cochrane reviews for the individual interventions were screened for studies fulfilling the inclusion criteria. The search strategy outlined by the Cochrane Back Review Groups (CBRG) was followed. The following were included for selection criteria: (1) randomized controlled trials, (2) adult (≥ 18 years) population with chronic (≥ 12 weeks) non-specific LBP, and (3) evaluation of at least one of the main clinically relevant outcome measures (pain, functional status, perceived recovery, or return to work). Two reviewers independently selected studies and extracted data on study characteristics, risk of bias, and outcomes at short, intermediate, and long-term follow-up. The GRADE approach was used to determine the quality of evidence. In total 83 randomized controlled trials met the inclusion criteria: exercise therapy (n = 37), back school (n = 5), TENS (n = 6), low level laser therapy (n = 3), behavioural treatment (n = 21), patient education (n = 1), traction (n = 1), and multidisciplinary treatment (n = 6). Compared to usual care, exercise therapy improved post-treatment pain intensity and disability, and long-term function. Behavioural treatment was found to be effective in reducing pain intensity at short-term follow-up compared to no treatment/waiting list controls. Finally, multidisciplinary treatment was found to reduce pain intensity and disability at short-term follow-up compared to no treatment/waiting list controls. Overall, the level of evidence was low. Evidence from randomized controlled trials demonstrates that there is low quality evidence for the effectiveness of exercise therapy compared to usual care, there is low evidence for the effectiveness of behavioural therapy compared to no treatment and there is moderate evidence for the effectiveness of a multidisciplinary treatment compared to no treatment and other active treatments at reducing pain at short-term in the treatment of chronic low back pain. Based on the heterogeneity of the populations, interventions, and comparison groups, we conclude that there are insufficient data to draw firm conclusion on the clinical effect of back schools, low-level laser therapy, patient education, massage, traction, superficial heat/cold, and lumbar supports for chronic LBP.

Transcutaneous electrical nerve stimulation (TENS) versus placebo for chronic low-back pain

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) was introduced more than 30 years ago as a therapeutic adjunct to the pharmacological management of pain. However, despite widespread use, its effectiveness in chronic low-back pain (LBP) is still controversial.

OBJECTIVES

To determine whether TENS is more effective than placebo for the management of chronic LBP.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, PEDro and CINAHL were searched up to July 19, 2007.

SELECTION CRITERIA

Only randomized controlled clinical trials (RCTs) comparing TENS to placebo in patients with chronic LBP were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the trials, assessed their methodological quality and extracted relevant data. If quantitative meta-analysis was not possible, a qualitative synthesis was performed, taking into consideration 5 levels of evidence as recommended by the Cochrane Collaboration Back Review Group.

MAIN RESULTS

Four high-quality RCTs (585 patients) met the selection criteria. Clinical heterogeneity prevented the use of meta-analysis. Therefore, a qualitative synthesis was completed. There was conflicting evidence about whether TENS was beneficial in reducing back pain intensity and consistent evidence in two trials (410 patients) that it did not improve back-specific functional status. There was moderate evidence that work status and the use of medical services did not change with treatment. Conflicting results were obtained from two studies regarding generic health status, with one study showing no improvement on the modified Sickness Impact Profile and another study showing significant improvements on several, but not all subsections of the SF-36 questionnaire. Multiple physical outcome measures lacked statistically significant improvement relative to placebo. In general, patients treated with acupuncture-like TENS responded similarly to those treated with conventional TENS. However, in two of the trials, an inadequate stimulation intensity was used for acupuncture-like TENS, given that muscle twitching was not induced. Optimal treatment schedules could not be reliably determined based on the available data. Adverse effects included minor skin irritation at the site of electrode placement.

AUTHORS' CONCLUSIONS

At this time, the evidence from the small number of placebo-controlled trials does not support the use of TENS in the routine management of chronic LBP. Further research is encouraged.

Transcutaneous electrical nerve stimulation (TENS) for chronic pain

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is a popular pain treatment modality but its effectiveness in chronic pain management is unknown. This review is an update of the original Cochrane review published in Issue 3, 2001.

OBJECTIVES

To evaluate the effectiveness of TENS in chronic pain.

SEARCH STRATEGY

The Cochrane Library, EMBASE, MEDLINE and CINAHL were searched. Reference lists from retrieved reports and reviews were examined. Date of the most recent search: April 2008.

SELECTION CRITERIA

RCTs were eligible if they compared active TENS versus sham TENS controls; active TENS versus 'no treatment' controls; or active TENS versus active TENS controls (e.g. High Frequency TENS (HFTENS) versus Low Frequency TENS (LFTENS)). Studies of chronic pain for three months or more which included subjective outcome measures for pain intensity or relief were eligible for evaluation. No restrictions were made to language or sample size. Abstracts, letters, or unpublished studies, and studies of TENS in angina, headache, migraine, dysmenorrhoea and cancer-related pain were excluded.

DATA COLLECTION AND ANALYSIS

Data were extracted and summarised on the following items: patients and details of pain condition, treatments, study duration, design, methods, subjective pain outcome measures, methodological quality, results for pain outcome measures and adverse effects, and conclusions by authors of the studies. Extracted data and methodological quality of studies were confirmed by the review authors.

MAIN RESULTS

Of 124 studies identified from the searches, 99 did not fulfil pre-defined entry criteria. Twenty-five RCTs involving 1281 participants were evaluated. Included studies varied in design, analgesic outcomes, chronic pain conditions, TENS treatments and methodological quality. The reporting of methods and results for analgesic outcomes were inconsistent across studies and generally poor. Meta-analysis was not possible. Overall in 13 of 22 inactive control studies, there was a positive analgesic outcome in favour of active TENS treatments. For multiple dose treatment comparison studies, eight of fifteen were considered to be in favour of the active TENS treatments. Seven of the nine active controlled studies found no difference in analgesic efficacy between High Frequency (HF) TENS and Low Frequency (LF) TENS.

AUTHORS' CONCLUSIONS

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.

Effects of electroacupuncture on a degenerated intervertebral disc using an in-vivo rat-tail model

Electroacupuncture (EA) has long been used as conservative treatment for low back pain (LBP). Its effect on relief of back pain has been demonstrated in many clinical studies. However, whether it has any effect on the biological properties of an intervertebral disc, which is one of the major causes of LBP, is still unclear. The aim of this study was, therefore, to investigate the effects of EA with different simulation frequencies on an intervertebral disc with simulated degeneration using an in-vivo rat-tail model. In this study, 33 rats were used. Disc degeneration was simulated in the rat caudal 8-9 disc via continuous static compressive loading of 11 N for 2 weeks. EA with a frequency of 2 or 100 Hz was then applied to the degenerated disc for 3 weeks with 3 sessions/week and 20 min/session. The intervertebral disc height was measured before and after compression as well as after EA intervention for 3 weeks. The static compression was found to result in a reduction in the disc height of about 22 per cent. There was no evidence that this change could be reversed after resting or the EA intervention. However, EA at 100 Hz was found to induce a further decrease in disc height, which was not shown for the rats after resting or EA at 2 Hz. The results of this study showed that effects of EA on disc degeneration are frequency dependent and adverse effects could result if EA at a certain frequency was used.

Acupuncture analgesia: II. Clinical considerations

BACKGROUND

Acupuncture and related percutaneous neuromodulation therapies can be used to treat patients with both acute and chronic pain. In this review, we critically examined peer-reviewed clinical studies evaluating the analgesic properties of acupuncture modalities.

METHODS

Using Ovid and published medical databases, we examined prospective, randomized, sham-controlled clinical investigations involving the use of acupuncture and related forms of acustimulation for the management of pain. Case reports, case series, and cohort studies were not included in this analysis.

RESULTS

Peer-reviewed literature suggests that acupuncture and other forms of acustimulation are effective in the short-term management of low back pain, neck pain, and osteoarthritis involving the knee. However, the literature also suggests that short-term treatment with acupuncture does not result in long-term benefits. Data regarding the efficacy of acupuncture for dental pain, colonoscopy pain, and intraoperative analgesia are inconclusive. Studies describing the use of acupuncture during labor suggest that it may be useful during the early stages, but not throughout the entire course of labor. Finally, the effects of acupuncture on postoperative pain are inconclusive and are dependent on the timing of the intervention and the patient's level of consciousness.

CONCLUSIONS

Current data regarding the clinical efficacy of acupuncture and related techniques suggest that the benefits are short-lasting. There remains a need for well designed, sham-controlled clinical trials to evaluate the effect of these modalities on clinically relevant outcome measures such as resumption of daily normal activities when used in the management of acute and chronic pain syndromes.

Evidence-informed management of chronic low back pain with transcutaneous electrical nerve stimulation, interferential current, electrical muscle stimulation, ultrasound, and thermotherapy

The management of chronic low back pain (CLBP) has proven to be very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing among available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions most likely to result in clinically meaningful improvements, there is often uncertainty about the most appropriate intervention for a particular patient. To help understand and evaluate the various commonly used nonsurgical approaches to CLBP, the North American Spine Society has sponsored this special focus issue of The Spine Journal, titled Evidence-Informed Management of Chronic Low Back Pain Without Surgery. Articles in this special focus issue were contributed by leading spine practitioners and researchers, who were invited to summarize the best available evidence for a particular intervention and encouraged to make this information accessible to nonexperts. Each of the articles contains five sections (description, theory, evidence of efficacy, harms, and summary) with common subheadings to facilitate comparison across the 24 different interventions profiled in this special focus issue, blending narrative and systematic review methodology as deemed appropriate by the authors. It is hoped that articles in this special focus issue will be informative and aid in decision making for the many stakeholders evaluating nonsurgical interventions for CLBP.

Evidence-informed management of chronic low back pain with trigger point injections

The management of chronic low back pain (CLBP) has proven very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing amongst available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions most likely to result in clinically meaningful improvements, there is often uncertainty about the most appropriate intervention for a particular patient. To help understand and evaluate the various commonly used nonsurgical approaches to CLBP, the North American Spine Society has sponsored this special focus issue of The Spine Journal, titled Evidence-Informed Management of Chronic Low Back Pain Without Surgery. Articles in this special focus issue were contributed by leading spine practitioners and researchers, who were invited to summarize the best available evidence for a particular intervention and encouraged to make this information accessible to nonexperts. Each of the articles contains five sections (description, theory, evidence of efficacy, harms, and summary) with common subheadings to facilitate comparison across the 24 different interventions profiled in this special focus issue, blending narrative and systematic review methodology as deemed appropriate by the authors. It is hoped that articles in this special focus issue will be informative and aid in decision making for the many stakeholders evaluating nonsurgical interventions for CLBP.

Transcutaneous electrical nerve stimulation for the treatment of chronic low back pain: a systematic review

STUDY DESIGN

Systematic review.

OBJECTIVE

To determine the effectiveness of transcutaneous electrical nerve stimulation (TENS) in the management of chronic LBP.

SUMMARY OF BACKGROUND DATA

Chronic low back pain (LBP) affects a significant proportion of the population. TENS was introduced more than 30 years ago as an adjunct to pharmacologic pain management. However, despite its widespread use, the usefulness of TENS in chronic LBP is still controversial.

METHODS

We searched MEDLINE, EMBASE, PEDro, and the Cochrane Central Register of Controlled Trials (Issue 2, 2005), up to April 1, 2005. Only randomized controlled clinical trials (RCTs) evaluating the effect of TENS on chronic LBP were included. Two reviewers independently selected trials and extracted data using predetermined forms. Heterogeneity was tested with Cochrane's Q test. A fixed effect model was used throughout for calculating continuous variables, except where heterogeneity existed, in which case a random effects model was used. Results are presented as weighted mean differences with 95% confidence intervals (95% CI), where the difference between the treated and control groups was weighted by the inverse of the variance. Standardized mean differences were calculated by dividing the difference between the treated and control by the baseline variance. Standardized mean differences were used when different scales were used to measure the same concept. Dichotomous outcomes were analyzed with odds ratios.

RESULTS

Two RCTs (175 patients) were included. They differed with respect to study design, methodologic quality, inclusion and exclusion criteria, characteristics of TENS application, treatment schedule, cointerventions, and measured outcomes. In one RCT, TENS produced significantly greater pain relief than the placebo control. However, in the other RCT, no statistically significant differences between treatment and control groups were shown for multiple outcome measures. Preplanned subgroup analyses, intended to examine the impact of different stimulation parameters, sites of TENS application, treatment durations, and baseline patient characteristics were not possible because of the small number of included trials.

CONCLUSIONS

Evidence for the efficacy of TENS as an isolated intervention in the management of chronic LBP is limited and inconsistent. Larger, multicenter, RCTs are needed to better resolve its role in this condition. Increased attention should be given to the risks and benefits of long-term use, which more appropriately addresses the realities of managing chronic low back pain.

Transcutaneous electrical nerve stimulation (TENS) for chronic low-back pain

BACKGROUND

Chronic low-back pain (LBP) affects a significant proportion of the population. Transcutaneous electrical nerve stimulation (TENS) was introduced more than 30 years ago as an adjunct to the pharmacological management of pain. However, despite its widespread use, the usefulness of TENS in chronic LBP is still controversial.

OBJECTIVES

The aim of this systematic review was to determine the effectiveness of TENS in the management of chronic LBP.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (Issue 2, 2005), MEDLINE, EMBASE and PEDro up to April 1, 2005.

SELECTION CRITERIA

Only randomized controlled clinical trials (RCTs) evaluating the effect of TENS on chronic LBP were included. Abstracts were excluded unless further data could be obtained from the authors.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials and extracted data using predetermined forms. Heterogeneity was tested with Cochrane's Q test. A fixed effect model was used throughout for calculating continuous variables, except where heterogeneity existed, in which case, a random effects model was used. Results are presented as weighted mean differences (WMD) with 95% confidence intervals (95% CI), where the difference between the treated and control groups was weighted by the inverse of the variance. Standardized mean differences (SMD) were calculated by dividing the difference between the treated and control by the baseline variance. SMD were used when different scales were used to measure the same concept. Dichotomous outcomes were analyzed with odds ratios.

MAIN RESULTS

The only two RCTs (175 patients) meeting eligibility criteria differed in study design, methodological quality, inclusion and exclusion criteria, type and method of TENS application, treatment schedule, co-interventions and final outcomes. In one RCT, TENS produced significantly greater pain relief than the placebo control. However, in the other RCT, no statistically significant differences between treatment and control groups were shown for multiple outcome measures. Pre-planned subgroup analyses, intended to examine the impact of different stimulation parameters, sites of TENS application, treatment durations and baseline patient characteristics were not possible due to the small number of included trials.

AUTHORS' CONCLUSIONS

There is inconsistent evidence to support the use of TENS as a single treatment in the management of chronic LBP. Larger, multi-center, randomized controlled trials are needed to better assess the true effectiveness of TENS. Special attention should be given to the risks and benefits of long-term use, which more appropriately addresses the realities of managing chronic low-back pain.