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

Transcutaneous Electrical Acupoint Stimulation Combined with Moderate Sedation of Remimazolam Tosilate in Gastrointestinal Endoscopy: A Prospective, Randomized, Double-Blind, Placebo-Controlled Clinical Trial

INTRODUCTION

Further clinical validation is required to determine whether transcutaneous electrical acupoint stimulation (TEAS) can replace opioids and be used in combination with remimazolam for sedation during gastrointestinal endoscopy.

METHODS

A total of 108 outpatients who underwent diagnostic gastrointestinal endoscopy were randomly divided into three groups: fentanyl plus remimazolam group (group C), TEAS plus remimazolam group (group E), and placebo-TEAS plus remimazolam group (group P). The assessments of patient satisfaction, physician satisfaction, and pain scale score during the examination constituted the primary endpoints of the study. The secondary endpoints were the time of recovery, recovery of normal behavioral function and discharge, incidence of adverse reactions, and dose of remimazolam.

RESULTS

Compared with group C, group E had a greater median score for patient satisfaction at follow-up and a slightly lower median score for physician satisfaction. The pain score of group E was slightly greater than that of group C, but the difference was not significant. However, in group C, the incidence of hypoxemia, the rate of nausea and the severity of vertigo were greater, and the number of patients discharged and resuming normal behavioral function was greater than those in the other two groups. The dose of remimazolam in group C and group E was less than that in group P.

CONCLUSIONS

TEAS combined with moderate sedation of remimazolam can provide an ideal sedative effect, which preferably suppresses discomfort caused by gastrointestinal endoscopy and has fewer sedation-related complications.

TRIAL REGISTRATION

ID: NCT05485064; First registration (29/07/2022); Last registration (02/11/2022) (Clinical Trials.gov).

A hybrid sensory feedback system for thermal nociceptive warning and protection in prosthetic hand

Background

Advanced prosthetic hands may embed nanosensors and microelectronics in their cosmetic skin. Heat influx may cause damage to these delicate structures. Protecting the integrity of the prosthetic hand becomes critical and necessary to ensure sustainable function. This study aims to mimic the sensorimotor control strategy of the human hand in perceiving nociceptive stimuli and triggering self-protective mechanisms and to investigate how similar neuromorphic mechanisms implemented in prosthetic hand can allow amputees to both volitionally release a hot object upon a nociceptive warning and achieve reinforced release via a bionic withdrawal reflex.

Methods

A steady-state temperature prediction algorithm was proposed to shorten the long response time of a thermosensitive temperature sensor. A hybrid sensory strategy for transmitting force and a nociceptive temperature warning using transcutaneous electrical nerve stimulation based on evoked tactile sensations was designed to reconstruct the nociceptive sensory loop for amputees. A bionic withdrawal reflex using neuromorphic muscle control technology was used so that the prosthetic hand reflexively opened when a harmful temperature was detected. Four able-bodied subjects and two forearm amputees randomly grasped a tube at the different temperatures based on these strategies.

Results

The average prediction error of temperature prediction algorithm was 8.30 ± 6.00%. The average success rate of six subjects in perceiving force and nociceptive temperature warnings was 86.90 and 94.30%, respectively. Under the reinforcement control mode in Test 2, the median reaction time of all subjects was 1.39 s, which was significantly faster than the median reaction time of 1.93 s in Test 1, in which two able-bodied subjects and two amputees participated. Results demonstrated the effectiveness of the integration of nociceptive sensory strategy and withdrawal reflex control strategy in a closed loop and also showed that amputees restored the warning of nociceptive sensation while also being able to withdraw from thermal danger through both voluntary and reflexive protection.

Conclusion

This study demonstrated that it is feasible to restore the sensorimotor ability of amputees to warn and react against thermal nociceptive stimuli. Results further showed that the voluntary release and withdrawal reflex can work together to reinforce heat protection. Nevertheless, fusing voluntary and reflex functions for prosthetic performance in activities of daily living awaits a more cogent strategy in sensorimotor control.

The dose-dependent effects of transcutaneous electrical nerve stimulation for pain relief in individuals with fibromyalgia: a systematic review and meta-analysis

ABSTRACT

Transcutaneous electrical nerve stimulation (TENS) is a nonpharmacological modality widely used to manage pain; however, its effectiveness for individuals with fibromyalgia (FM) has been questioned. In previous studies and systematic reviews, variables related to dose of TENS application have not been considered. The objectives of this meta-analysis were (1) to determine the effect of TENS on pain in individuals with FM and (2) determine the dose-dependent effect of TENS dose parameters on pain relief in individuals with FM. We searched the PubMed, PEDro, Cochrane, and EMBASE databases for relevant manuscripts. Data were extracted from 11 of the 1575 studies. The quality of the studies was assessed using the PEDro scale and RoB-2 assessment. This meta-analysis was performed using a random-effects model that, when not considering the TENS dosage applied, showed that the treatment had no overall effect on pain (d+ = 0.51, P > 0.050, k = 14). However, the moderator analyses, which were performed assuming a mixed-effect model, revealed that 3 of the categorical variables were significantly associated with effect sizes: the number of sessions (P = 0.005), the frequency (P = 0.014), and the intensity (P = 0.047). The electrode placement was not significantly associated with any effect sizes. Thus, there is evidence that TENS can effectively reduce pain in individuals with FM when applied at high or at mixed frequencies, a high intensity, or in long-term interventions involving 10 or more sessions. This review protocol was registered at PROSPERO (CRD42021252113).

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.

Transcutaneous electrical nerve stimulation (TENS) for the treatment of renal colic in the emergency department: A randomized, double-blind, placebo-controlled trial

STUDY OBJECTIVE

To determine the analgesic efficacy of TENS treatment in patients with renal colic in the emergency department (ED).

METHODS

This double-blind, randomized controlled trial was conducted in a tertiary care ED. Patients with a definitive diagnosis of renal colic were assigned (1:1) as randomized to receive the real TENS with frequency 100 Hz, pulse width 200 microseconds, voltage 2 mA, or placebo with sham TENS. Pain intensity was measured using visual analog scales (VAS) at baseline, after 15 and 30th minutes.

RESULTS

A total of 100 patients were included in the final analysis: 50 patients treated with real TENS and 50 patients treated with sham TENS. VAS scores in both groups were similar at baseline. The mean reduction in VAS score at 15 min was 33.3 ± 17.6 (95% Confidence interval (CI): 28.3 to 38.3) for the real TENS group and 14.9 ± 11.6 (95% CI 11.6 to 18.2) for the sham TENS group (mean difference: 18.4 (95% CI: 12.5 to 24.4, P < 0.0001). The mean reduction in VAS score at 30 min was 63.7 ± 21.1 (95% CI: 57.7 to 69.7) for the real TENS group and 14.9 ± 16.2 (95% CI: 19.5 to 10.3) for the sham TENS group (mean difference: 48.8, 95% CI: 41.4 to 56.3, P < 0.0001). Four patients (8%) in the real TENS group and 24 patients (48%) in the sham TENS group required the rescue medication after 30th minutes.

CONCLUSIONS

TENS is effective for acute pain treatment in renal colic patients in the ED. TENS therapy could be a treatment option for renal colic.

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.

Smartphone-controlled patch electro-acupuncture versus conventional pain relief during colonoscopy: a randomized controlled trial

BACKGROUND

Smartphone-controlled patch electro-acupuncture (SCEA) is a novel device which gives the same analgesic effect as with conventional acupuncture. There are no published articles in the English literature on the use of this device as a primary mode of pain relief during colonoscopy. Primary aims of this study were to investigate the efficacy of SCEA as a substitute for pain relief during colonoscopy.

METHODS

Thirty-seven patients were randomized to receive SCEA (n = 19) or placebo (n = 18) during colonoscopy. Additional rescue sedation was administered to patients if they had pain or discomfort during the procedure. Visual analogue scale was used to quantify the intensity of pain from the beginning to end of the procedure. Other variables analysed were the amount of sedation used, duration from start to caecal intubation, length of time for completion of colonoscopy and recovery time to home discharge.

RESULTS

Patients who received SCEA had a lower median pain score of 4.6 (interquartile range 5.7) compared to the placebo group of 6.0 (interquartile range 3.2). Statistical analysis comparing the groups revealed a non-significant P-value of 0.12, although more than 90% of the patients indicated willingness for SCEA as the primary analgesia if they were to repeat the procedure. Throughout the study, there were no adverse complications that occurred during the use of SCEA.

CONCLUSIONS

Even though this study did not demonstrate, a significance in pain reduction, SCEA remains a safe modality which, more than 90% of patients favoured as a substitute for pain relief during colonoscopy.

Feasibility of a transmucosal sublingual fentanyl tablet as a procedural pain treatment in colonoscopy patients: a prospective placebo-controlled randomized study

Since patients often experience pain and unpleasantness during a colonoscopy, the present study aimed to evaluate the efficacy and safety of sublingually administered fentanyl tablets for pain treatment. Furthermore, since the use of intravenous drugs significantly increases colonoscopy costs, sublingual tablets could be a cost-effective alternative to intravenous sedation. We conducted a prospective placebo-controlled randomized study of 158 patients to evaluate the analgesic effect of a 100 µg dose of sublingual fentanyl administered before a colonoscopy. Pain, sedation, nausea, and satisfaction were assessed during the colonoscopy by the patients as well as the endoscopists and nurses. Respiratory rate and peripheral arteriolar oxygen saturation were monitored throughout the procedure. There were no differences between the fentanyl and placebo groups in any of the measured variables. The median pain intensity values, as measured using a numerical rating scale, were 4.5 in the fentanyl group and 5 in the placebo group. The sedation and oxygen saturation levels and the respiratory rate did not differ between the groups. The majority of the colonoscopies were completed.Our results indicate that a 100 µg dose of sublingual fentanyl is not beneficial compared to the placebo in the treatment of procedural pain during a colonoscopy.

Non-pharmacological interventions to improve the patient experience of colonoscopy under moderate or no sedation: a systematic review protocol

INTRODUCTION

The patient experience is a critical dimension of colonoscopy quality. Sedative and analgesic drugs are commonly used to improve the patient experience of colonoscopy, with predominant regimens being deep sedation, typically achieved with propofol, and moderate sedation, typically achieved with an opioid and a benzodiazepine. However, non-pharmacological interventions exist that may be used to improve patient experience. Furthermore, by identifying non-pharmacological interventions to increase the quality of patient experience under moderate sedation, jurisdictions facing rising use of deep sedation for colonoscopy and its significant associated costs may be better able to encourage patients and clinicians to adopt moderate sedation. Advancing either of these aims requires synthesising the evidence and raising awareness around these non-pharmacological interventions to improve the patient experience of colonoscopy.

METHODS AND ANALYSIS

A systematic review will be conducted that searches multiple electronic databases from inception until 2020 to identify randomised controlled trials evaluating what, if any, non-pharmacological interventions are effective compared with placebo or usual care for improving the patient experience of routine colonoscopy under moderate or no sedation. Two reviewers will independently perform a three-stage screening process and extract all study data using piloted forms. Study quality will be assessed using the Cochrane Risk of Bias Tool V.2.0. Where multiple studies evaluate a single intervention, evidence will be quantitatively synthesised using pairwise meta-analysis, otherwise narrative syntheses will be undertaken.

ETHICS AND DISSEMINATION

This is a review of existing literature not requiring ethics approval. The review findings will be included in future efforts to develop an implementation strategy to reduce the use of deep sedation for routine colonoscopy. They will also be published in a peer-reviewed journal, presented at conferences and contribute to a doctoral thesis.

PROSPERO REGISTRATION NUMBER

CRD42020173906.

Transcutaneous electrical nerve stimulation is superior than placebo and control for postoperative pain relief

Aim: To determine whether transcutaneous electrical nerve stimulation (TENS) is more efficient than placebo TENS and control groups for pain relief. Design: Randomized, single-blinded, placebo-controlled trial. Setting & participants: A total of 78 adults with postoperative pain, after cholecystectomy, at the University Hospital. They were randomized into active TENS, placebo TENS and control. Intervention: A total of 30-min interventions applied in the first 24 h after the surgery. Outcome: Pain intensity. Results: Pain significantly decreased for both TENS; however, the active TENS was better. A decrease of 2 points or more on the visual analog scale for 53.8% active TENS and 11.5% placebo. Conclusion: There was a greater reduction in pain of important clinical relevance in the active TENS group.

Clinical Trial registration: Brazilian Clinical Trial (REBEC): RBR-6cgx2k.

Does Frequency Modulation of Transcutaneous Electrical Nerve Stimulation Affect Habituation and Mechanical Hypoalgesia? A Randomized, Double-Blind, Sham-Controlled Crossover Trial

BACKGROUND

Devices for applying transcutaneous electrical nerve stimulation (TENS) use numerous frequency modulation patterns for decreasing habituation to currents. However, there is no evidence supporting the use of an optimal pattern instead of the others, or even modulated frequencies instead of a fixed frequency.

OBJECTIVE

The objectives of this study were to determine the effects of 3 TENS patterns (fixed frequency, random modulation, and 6-second-6-second [6s-6s] modulation) on habituation, to examine the subjective perception of habituation and comfort, and to determine their effects on the mechanical pain threshold (MPT).

DESIGN

This study was a randomized, double-blind, sham-controlled crossover trial.

SETTING

The study took place in a university research laboratory under attenuated noise conditions at a regulated temperature of 22°C to 26°C.

PARTICIPANTS

Thirty-nine volunteers who were healthy participated in this trial.

INTERVENTION

The participants received 4 different TENS interventions (fixed frequency, random modulation, 6s-6s modulation, and sham) in random order, with a 24-hour washout period, on the radial nerve.

MEASUREMENTS

The main outcome-habituation-was quantified by the increase in current density and the number of times the intensity had to be increased during the session. Secondary outcome variables were subjective perception of habituation and comfort and MPT.

RESULTS

Random modulation reduced the number of times the intensity had to be increased because of habituation compared with no modulation (1.6 times; 95% confidence interval [CI] = 0.7-2.6) and 6s-6s modulation (0.8 times; 95% CI = 0.01-1.6). No differences were observed between interventions in terms of an increase in current density, self-perceived habituation, or self-perceived comfort. MPT increased during the intervention in the random-modulation group (4.4 N; 95% CI = 1.8-7.0) and the no-modulation group (5.9 N; 95% CI = 1.9-10.0); there were no significant changes in the other 2 groups.

LIMITATIONS

The success of masking or blinding procedures of the participants was not assessed.

CONCLUSIONS

Randomly modulated frequencies caused less habituation than nonmodulated frequencies or 6s-6s modulation. Further research on more prolonged (hours-long) interventions in participants with pain is required.

A Comparative Study between Transcutaneous Electrical Nerve Stimulation and Fentanyl to Relieve Shoulder Pain during Laparoscopic Gynecologic Surgery under Spinal Anesthesia: A Randomized Clinical Trail

Background

Traditionally, laparoscopic procedures have been performed under general anesthesia. Spinal anesthesia is an effective alternative to general anesthesia. However, one of the intraoperative complications of performing laparoscopic surgery under spinal anesthesia is shoulder pain. This study aimed to compare the effect of transcutaneous electrical nerve stimulation (TENS) with fentanyl on pain relief in patients who underwent gynecologic laparoscopy under spinal anesthesia.

Methods

We conducted a prospective randomized clinical trial from May 2016 to March 2017. A sample of patients who underwent gynecological laparoscopy under spinal anesthesia was recruited. If they had shoulder pain, they randomly received either transcutaneous electrical nerve stimulation (TENS) or 50 mg of fentanyl. Pain intensity was measured using the single item visual analogue scale (VAS-10 cm) immediately before and 5, 10, 20, and 30 minutes after treatment. Also, the effect of higher doses of analgesia on pain relief was analyzed.

Results

In all, 80 patients (40 patients in each group) were entered into the study. The mean pain intensity score was 9.02 ± 1.32 in the TENS group and 8.95 ± 1.33 in the fentanyl group at baseline (P = 0.80). Repeated measures analysis of variance indicated that there was no significant difference on overall pain scores between the two treatment groups adjusted for age, BMI, total analgesia used, and baseline pain score (F (1, 74) = 1.44, P = 0.23). The use of analgesic drugs in the TENS group was significantly higher than the fentanyl group (P = 0.01). In addition, we found that nine patients (22.5%) complained of nausea/vomiting in the TENS group compared to thirteen patients (32.5%) in the fentanyl group (P = 0.31).

Conclusions

The findings indicated that TENS was not superior to fentanyl for pain relief in laparoscopic surgery. It seems that the correct use of TENS parameters might merit further investigation. This trial is registered with: IRCT2016031216765N3.

Transcutaneous electrical nerve stimulation for acute pain

BACKGROUND

This is a second update of a Cochrane Review originally published in Issue 2, 2009. Transcutaneous Electrical Nerve Stimulation (TENS) is a non-pharmacological agent, based on delivering low voltage electrical currents to the skin. TENS is used by people to treat a variety of pain conditions.

OBJECTIVES

To assess the analgesic effectiveness of TENS, as a sole treatment, for acute pain in adults.

SEARCH METHODS

We searched the following databases up to 3 December 2014: the Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library; MEDLINE; EMBASE; CINAHL; and AMED. We also checked the reference lists of included trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of adults with acute pain (< 12 weeks) if they examined TENS given as a sole treatment and assessed pain with subjective pain scales. Trials were eligible if they compared TENS to placebo TENS, no treatment controls, pharmacological interventions or non-pharmacological interventions. We excluded trials on experimental pain, case reports, clinical observations, letters, abstracts or reviews. Also we excluded trials investigating the effect of TENS on pain during childbirth (labour), primary dysmenorrhoea or dental procedures. Studies where TENS was given with another treatment as part of the formal trial design were excluded. We did not restrict any articles based on language of publication.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility and carried out study selection, data extraction, 'Risk of bias' assessment and analyses of data. We extracted data on the following: types of participants and pain condition, trial design and methods, treatment parameters, adverse effects, and outcome measures. We contacted trial authors for additional information if necessary.

MAIN RESULTS

We included 12 trials in the original review (2009) and included no further trials in the first update (2011). An additional seven new trials met the inclusion criteria in this second update. In total, we included 19 RCTs involving 1346 participants at entry, with 11 trials awaiting classification either because the full text was unavailable or information in the full text failed to clarify eligibility. We excluded most trials because TENS was given in combination with another treatment as part of the formal study design or TENS was not delivered using appropriate TENS technique. The types of acute pain included in this Cochrane Review were procedural pain, e.g. cervical laser treatment, venepuncture, screening flexible sigmoidoscopy and non-procedural pain, e.g. postpartum uterine contractions and rib fractures. We pooled data for pain intensity for six trials (seven comparisons) comparing TENS with placebo but the I(2) statistic suggested substantial heterogeneity. Mean difference (MD) with 95% confidence intervals (CIs) on a visual analogue scale (VAS, 100 mm) was -24.62 mm (95% CI -31.79 to -17.46) in favour of TENS. Data for the proportion of participants achieving ≥ 50% reduction in pain was pooled for four trials (seven comparisons) and relative risk was 3.91 (95% CI 2.42 to 6.32) in favour of TENS over placebo. We pooled data for pain intensity from five trials (seven comparisons) but the I(2) statistic suggested considerable heterogeneity. MD was -19.05 mm (95% CI -27.30 to -10.79) in favour of TENS using a random-effects model. It was not possible to pool other data. There was a high risk of bias associated with inadequate sample sizes in treatment arms and unsuccessful blinding of treatment interventions. Seven trials reported minor adverse effects, such as mild erythema and itching underneath the electrodes and participants disliking TENS sensation.

AUTHORS' CONCLUSIONS

This Cochrane Review update includes seven new trials, in addition to the 12 trials reviewed in the first update in 2011. The analysis provides tentative evidence that TENS reduces pain intensity over and above that seen with placebo (no current) TENS when administered as a stand-alone treatment for acute pain in adults. The high risk of bias associated with inadequate sample sizes in treatment arms and unsuccessful blinding of treatment interventions makes definitive conclusions impossible. There was incomplete reporting of treatment in many reports making replication of trials impossible.

Does transcutaneous electrical nerve stimulation (TENS) alleviate the pain experienced during bone marrow sampling in addition to standard techniques? A randomised, double-blinded, controlled trial

AIMS

Bone marrow aspiration and trephine (BMAT) biopsies remain important tests in haematology. However, the procedures can be moderately to severely painful despite standard methods of pain relief. To test the efficacy of transcutaneous electrical nerve stimulation (TENS) in alleviating the pain from BMAT in addition to standard analgesia using a numerical pain rating scale (NRS).

METHODS

70 patients requiring BMAT were randomised (1:1) in a double-blind, placebo-controlled trial. -35 patients received TENS impulses at a strong but comfortable amplitude (intervention group) and 35 patients received TENS impulses just above the sensory threshold (control group) (median pulse amplitude 20 and 7 mA, respectively). Patients and operators were blinded to group allocation. Pain assessments were made using a numerical pain scale completed after the procedure.

RESULTS

No significant difference in NRS pain recalled after the procedure was detected (median pain score 5.7 (95% CI 4.8 to 6.6) in control vs 5.6 (95% CI 4.8 to 6.4) in the intervention group). However, 100% of patients who had previous experience of BMAT and >94% of participants overall felt they benefited from using TENS and would recommend it to others for this procedure. There were no side effects from the TENS device, and it was well tolerated.

CONCLUSIONS

TENS is a safe, non-invasive adjunct to analgesia for reducing pain during bone marrow biopsy and provides a subjective benefit to most users; however, no objective difference in pain scores was detected when using TENS in this randomised controlled study.

CLINICAL REGISTRATION NUMBER

NCT02005354.