Stimulation-produced analgesia: acupuncture, TENS and related techniques

Effects of acupuncture on sensory symptoms and motor signs in patients with restless legs syndrome: A crossover randomized controlled trial

BACKGROUND

Rapid effects of acupoint injection (acuinjection) at 4 acupoints (4P) (ST36, GB41, SP6, and BL60) on legs presenting sensory symptoms and motor signs in restless legs syndrome (RLS) were first described in a case report. This study aimed to confirm the beneficial effects of acuinjection.

METHODS

A randomized, controlled, single-blinded, prospective crossover study was conducted during 2018 to 2021. Adult volunteers (age ≥ 20 years) with RLS symptoms for > 2 weeks were included. Eight adults were enrolled and randomized to receive acuinjection (Verum group) or sham injection (Sham group). The effects of acuinjection on discomfort and periodic leg movement (PLM) were evaluated using the suggested immobilization test in a crossover design. The acupoint used was 4P, and normal saline solution (0.1-0.25 mL) was injected in both groups. Leg discomfort was measured using the visual analog scale (VAS), and PLM was measured using an electromyogram. To compare the VAS scores between the groups, repeated measures analysis of variance was used, and the Student t test was used to assess the mean discomfort score (MLDS: average of the 6 VAS scores) and PLM index (PLMI) (defined as the degree of PLM/hour).

RESULTS

A significant difference in the VAS score was observed; however, no significant difference was noted in the PLMI between the groups. The MLDS was significantly lower in the Verum group than in the Sham group.

CONCLUSION

Acuinjection at 4P remarkably inhibited leg discomfort in patients with RLS. Despite the drastic PLM suppression in 1 patient by acuinjection, a statistically significant inhibition of PLM was not confirmed. The results of our study can be applied easily and safely in clinical situations where it is necessary to temporarily reduce or eliminate RLS symptoms.

Traditional acupuncture and laser acupuncture in chronic nonspecific neck pain: study protocol for a randomized controlled trial

Background

Nonspecific neck pain is a multifactorial and very common condition in adult individuals, traditional acupuncture (TA) and laser acupuncture (LA) may be treatment options for certain individuals in such a condition. However, no reports were found in the literature comparing the effectiveness of TA and LA in cases of chronic nonspecific neck pain. Therefore, the aim of the present study is to investigate the effectiveness of TA and LA therapies in individuals with chronic nonspecific neck pain, noting which one is more efficient for this condition. The result of this research will have direct implications for pain management and, consequently, may benefit individuals suffering from nonspecific chronic neck pain.

Methods/design

This will be a controlled and randomized clinical trial. Eighty-four individuals will be recruited and distributed equally and randomly into 3 groups: TA (which will receive the acupuncture treatment with needles), LA (which will receive the laser acupuncture treatment), and Sham (who will receive the placebo intervention). The acupuncture points (Tianzhu, Fengchi, Jianjing, and Jianzhongshu) will be stimulated bilaterally. The primary outcome will be pain intensity, determined using the Numerical Rating Scale. The secondary outcomes will be pressure pain threshold, temporal summation of pain, conditioned pain modulation, use of analgesic medicines after treatment, and the global perceived effect scale. The assessments will be performed immediately before and after the treatment, which will be a single session, at the follow-up and 1 month after the end of the treatments; evaluation will be made of the pain intensity and the global perceived effect. Statistical analysis of the data obtained will consider a significance level of p < 0.05.

Discussion

This study will provide evidence concerning the effects of LA treatment, in comparison with TA and sham intervention, leading to benefits for individuals suffering from chronic nonspecific neck pain.

Trial registration

Brazilian Registry of Clinical Trials - ReBEC RBR-7vbw5gd. Date of registration: August 06th, 2021.

Effect of lumbar spinal manipulation on local and remote pressure pain threshold and pinprick sensitivity in asymptomatic individuals: a randomised trial

BACKGROUND

The mechanisms of clinical pain relief associated with spinal manipulative therapy (SMT) are poorly understood. Our objective was to determine whether lumbar high-velocity low-amplitude SMT altered pressure pain threshold (PPT) and pinprick sensitivity (PPS) locally and remotely, how long any change lasted (up to 30 min), and whether changes related to the side of SMT.

METHODS

Thirty-four asymptomatic participants (mean age 22.6 years ±4.0) received a right- or left-sided lumbar SMT. PPT and PPS were measured bilaterally at the calf, lumbar spine, scapula, and forehead before and immediately, 10, 20, and 30 min after intervention. Data were collected between October 2014 and June 2015.

RESULTS

Bilateral calf and lumbar spine PPT increased significantly after 10 - 20 min and was maintained at 30 min (7.2-11.8 % increase). PPS decreased significantly in all locations at various times (9.8 - 22.5 % decrease). At the calf and lumbar spine, PPT increased slightly more ipsilateral to the SMT than contralateral.

CONCLUSIONS

Lumbar SMT reduced deep pressure sensitivity locally and in the lower limbs for at least 30 min, whereas sensitivity to pinprick was reduced systemically. These findings suggest that SMT specifically inhibits deep pressure sensitivity distally. These findings are novel compared to other lumbar SMT studies, and may reflect a local spinal or complex supraspinal analgesic mechanism.

TRIAL REGISTRATION

Registered with the Australian New Zealand Clinical Trials Registry (ACTRN12614000682640).

Effects of Neuromuscular Electrical Stimulation on the Masticatory Muscles and Physiologic Sleep Variables in Adults with Cerebral Palsy: A Novel Therapeutic Approach

Cerebral palsy (CP) is a term employed to define a group of non-progressive neuromotor disorders caused by damage to the immature or developing brain, with consequent limitations regarding movement and posture. CP may impair orapharygeal muscle tone, leading to a compromised chewing function and to sleep disorders (such as obstructive sleep apnea). Thirteen adults with CP underwent bilateral masseter and temporalis neuromuscular electrical stimulation (NMES) therapy. The effects on the masticatory muscles and sleep variables were evaluated using electromyography (EMG) and polysomnography (PSG), respectively, prior and after 2 months of NMES. EMG consisted of 3 tests in different positions: rest, mouth opening and maximum clenching effort (MCE). EMG values in the rest position were 100% higher than values recorded prior to therapy for all muscles analyzed (p < 0.05); mean mouth opening increased from 38.0 ± 8.0 to 44.0 ± 10.0 cm (p = 0.03). A significant difference in MCE was found only for the right masseter. PSG revealed an improved in the AHI from 7.2±7.0/h to 2.3±1.5/h (p < 0.05); total sleep time improved from 185 min to 250 min (p = 0.04) and minimun SaO2 improved from 83.6 ± 3.0 to 86.4 ± 4.0 (p = 0.04). NMES performed over a two-month period led to improvements in the electrical activity of the masticatory muscles at rest, mouth opening, isometric contraction and sleep variables, including the elimination of obstructive sleep apnea events in patients with CP.

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.

Habituation to experimentally induced electrical pain during voluntary-breathing controlled electrical stimulation (BreEStim)

Objective

Painful peripheral electrical stimulation to acupuncture points was found to cause sensitization if delivered randomly (EStim), but induced habituation if triggered by voluntary breathing (BreEStim). The objective was to systematically compare the effectiveness of BreEStim and EStim and to investigate the possible mechanisms mediating the habituation effect of BreEStim.

Methods

Eleven pain-free, healthy subjects (6 males, 5 females) participated in the study. Each subject received the BreEStim and EStim treatments in a random order at least three days apart. Both treatments consisted of 120 painful but tolerable stimuli to the ulnar nerve at the elbow on the dominant arm. BreEStim was triggered by voluntary breathing while EStim was delivered randomly. Electrical sensation threshold (EST) and electrical pain threshold (EPT) were measured from the thenar and hypothenar eminences on both hands at pre-intervention and 10-minutes post-intervention.

Results

There was no difference in the pre-intervention baseline measurement of EST and EPT between BreEStim and EStim. BreEStim increased EPT in all tested sites on both hands, while EStim increased EPT in the dominant hypothenar eminence distal to the stimulating site and had no effect on EPT in other sites. There was no difference in the intensity of electrical stimulation between EStim and BreEStim.

Conclusion

Our findings support the important role human voluntary breathing plays in the systemic habituation effect of BreEStim to peripheral painful electrical stimulation.

Reducing the pain of intramuscular benzathine penicillin injections in the rheumatic fever population of Counties Manukau District Health Board

AIM

To evaluate the effectiveness of lignocaine and a vibrating device with cold pack (Buzzy) for pain management of intramuscular (IM) benzathine penicillin injections in the rheumatic fever (RF) population of Counties Manukau District Health Board (CMDHB).

METHODS

Four hundred and five RF patients receiving four weekly injections in the CMDHB region were offered 0.25 mL of lignocaine 2% and Buzzy for pain management of their injections. The lignocaine was mixed in with the benzathine penicillin prior to administration. A pre and post survey assessed pain scores during, 2-min and 1-h post administration and the following day. Questions assessing fear were also included.

RESULTS

In total 49% of patients responded to the survey. There were 118 surveys paired pre and post intervention. Pain at injection delivery and fear scores were higher for participants ≤13 years of age. Overall pain scores were significantly reduced over all four time points. There was also a significant reduction in fear of the injections. Lignocaine and Buzzy resulted in a greater reduction in pain than lignocaine alone, only when the injection was being administered to those ≤13 years. After five months, a file audit showed that 66% of all RF patients of CMDHB were choosing to use lignocaine and 43% were choosing to use Buzzy. In total, 71% of all RF patients were choosing one or both of these analgesic interventions.

CONCLUSION

This study demonstrates a clinically important reduction in the subjective experience of pain when two analgesic interventions were offered with IM delivery of benzathine penicillin. These pain reduction strategies have been popular in the RF population of CMDHB with a 71% uptake and a corresponding reduction in pain and fear.