Peripheral nerve stimulation measures in a composite gradient system

Purpose: This work compared peripheral nerve stimulation (PNS) thresholds for the MRI scanner body gradients (BODY), a head/neck insert gradient (INSERT), and the combination of both gradient sets used simultaneously (COMPOSITE). Methods : For BODY, INSERT and COMPOSITE gradients, PNS thresholds were determined by exposing subject volunteers to stepped increases in gradient strength. For COMPOSITE mode, the INSERT was applied at equal (experiment 1) or double (experiment 2) the BODY gradient strength. Results: The locations and thresholds of peripheral nerve stimulation depended on the gradient system configuration, gradient axis, and gradient strength. Stimulation in the body occurred when using the BODY Y‐gradient axis either singly (110 T/m/s) or in COMPOSITE mode (315 T/m/s experiment 2) and adding the insert gradient had negligible effect on stimulation. Stimulation in the head/sinus area generally occurred when using the INSERT X‐gradient either singly (213 T/m/s) or in COMPOSITE mode (320 T/m/s) and adding the body gradient had negligible effect on stimulation. In the COMPOSITE mode, both the location of stimulation and the limiting gradient strength matched location and strength of the limiting component gradient. Conclusion: Stimulation, to a first‐order approximation, is independent for the two gradient systems. In COMPOSITE mode, PNS can be dominated by either of the individual gradient components, indicating that the contribution of each component can be increased until the threshold limit of each component gradient is reached. COMPOSITE gradients provide increased gradient performance with PNS thresholds higher than either component gradient system operating alone. © 2015 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 44B: 66–74, 2015     

Percutaneous Peripheral Nerve Stimulation for the Treatment of Chronic Low Back Pain: Two Clinical Case Reports of Sustained Pain Relief

As the leading cause of disability among U.S. adults, chronic low back pain (LBP) is one of the most prevalent and challenging musculoskeletal conditions. Neuromodulation provides an opportunity to reduce or eliminate the use of opioids to treat chronic LBP, but the cost and invasiveness of existing methods have limited its broad adoption, especially earlier in the treatment continuum. The present case report details the results of a novel method of short‐term percutaneous peripheral nerve stimulation (PNS) in 2 subjects with chronic LBP. At the end of the 1‐month therapy, stimulation was discontinued and the leads were withdrawn. PNS produced clinically significant improvements in pain (62% average reduction in Brief Pain Inventory Question #5, average pain), and functional outcomes (73% reduction in disability, Oswestry Disability Index; 83% reduction in pain interference, Brief Pain Inventory). Both subjects reduced nonopioid analgesic use by 83%, on average, and the one subject taking opioids ceased using all opioids. The only adverse event was minor skin irritation caused by a topical dressing. The clinically significant improvements were sustained at least 4 months after start of therapy (79% average reduction in pain; both reported minimal disability; 100% reduction in opioids; 74% reduction nonopioids). The results reveal the utility of this novel, short‐term approach and its potential as a minimally invasive neuromodulation therapy for use earlier in the treatment continuum to produce sustained pain relief and reduce or eliminate the need for analgesic medications, including opioids, as well as more expensive and invasive surgical or therapeutic alternatives.     

Peripheral Nerve Stimulation for the Treatment of Postamputation Pain—A Case Report

Many amputees suffer from postamputation pain, which can be extremely debilitating, decrease quality of life, increase the risk of depression, and negatively affect interpersonal relationships and the ability to work. Present methods of treatment, including medications, are often unsatisfactory in reducing postamputation pain. Electrical stimulation of the nerve innervating the painful area could reduce the pain, but peripheral nerve stimulation is rarely used to treat postamputation pain because present methods require invasive surgical access and precise placement of the leads in close proximity (≤ 2 mm) with the nerve. The present study investigated a novel approach to peripheral nerve stimulation in which a lead was placed percutaneously a remote distance (> 1 cm) away from the femoral nerve in a patient with severe residual limb pain (RLP) 33 years following a below‐knee amputation. Electrical stimulation generated ≥ 75% paresthesia coverage, reduced RLP by > 60%, and improved quality of life outcomes as measured by the pain interference scale of the Brief Pain Inventory‐Short Form (100% reduction in pain interference), Pain Disability Index (74% reduction in disability), and the Patient Global Impression of Change (very much improved) during a 2‐week home trial. There were no adverse events. The ability to generate significant paresthesia coverage and pain relief with a single lead inserted percutaneously and remotely from the target nerve holds promise for providing relief of postamputation pain.     

Occipital Neuromodulation: Ultrasound Guidance for Peripheral Nerve Stimulator Implantation

We report a case of chronic left‐sided occipital neuralgia in a 21‐year old female patient. The patient in question suffered from chronic greater occipital neuralgia for a duration of many years, which had been refractory to other conservative medical management strategies. Blockade of the greater occipital nerve with local anesthetic was consistently useful in attenuating the patient's pain, though the effects were always short lived. Consequently, a successful trial of greater occipital nerve stimulation was undertaken. Compared with spinal cord stimulation, peripheral nerve stimulation devices are often more difficult to precisely place given limited ability to visualize soft tissues with traditional fluoroscopic guidance. Additionally, there are anatomic subtleties relevant to the greater occipital nerve that potentially complicate stimulator lead placement, both from the standpoint of optimal neuromodulation efficacy and maximum safety. Ultrasound technology is a maturing imaging modality that allows soft tissue visualization and is consequently useful in addressing each of these aforementioned concerns. The specific use of high‐frequency ultrasound guidance for this procedure simplified the initial device placement and allowed proper visualization of soft tissue structures, which facilitates precise device deployment. Additionally, the ability to identify relevant vascular structures may further increase the safety of stimulator lead placement. The potential advantages of ultrasound‐augmented procedural techniques, specifically as they pertain to occipital stimulator lead placement, are discussed with particular emphasis on potentially decreasing intraoperative and postoperative complications while optimizing stimulation efficacy.     

Low-frequency transcutaneous nerve stimulation in mild/moderate hypertension

Summary. Low-frequency peripheral nerve stimulation may induce widespread cutaneous and muscular vasodilatation in animals and humans due to sympatho-inhibition. This response has in humans been shown to be associated with a lowering of the systemic vascular resistance and arterial pressure. In the present study the effectiveness of low-frequency (2 Hz) transcutaneous electrical nerve stimulation (TNS) has been examined in 46 patients, all 41–43 years of age, with a primary diagnosis of uncomplicated mild/moderate hypertension (90–115 mmHg diastolic pressure). The study was designed blind with matched controls in a TNS group and a placebo group. The blood pressure was measured objectively with an automatic monitor. In a short-term experiment TNS produced a significant lowering of systolic, mean arterial, and diastolic pressures amounting to 8 mmHg (P<0·01), 6 mmHg (P<0·01), and 4 mmHg (P<0·02), respectively. In a long-term study, after 2 weeks of daily stimulation, a similar depression was recorded with no stimulation on the day of examination. An eventual clinical use of the depressor effect of TNS demands further clinical research.     

Transcutaneous Electrical Nerve Stimulation Reduces Acute Low Back Pain during Emergency Transport

Background: Patients with acute low back pain may require emergency transport because of pain and immobilization. Transcutaneous electrical nerve stimulation (TENS) is a nonpharmaceutical therapy for patients with low back pain. Objective: To evaluate the efficacy of paramedic‐administered TENS in patients with acute low back pain during emergency transport. Methods: This was a prospective, randomized study involving 74 patients transported to hospital. The patients were randomly assigned to two groups: group 1 (n= 36) was treated with true TENS, while group 2 (n= 36) was treated with sham TENS. The authors recorded pain and anxiety as the main outcome variables using a visual analog scale (VAS). Results: The authors recorded a significant (p < 0.01) pain reduction (mean ± standard deviation) during transport in group 1 (79.2 ± 6.5 mm VAS to 48.9 ± 8.2 mm VAS), whereas pain scores remained unchanged in group 2 (75.9 ± 16.4 mm VAS and 77.1 ± 11.2 mm VAS). Similarly, the scores for anxiety were significantly reduced (p < 0.01) in group 1 (81.7 ± 7.9 mm VAS to 69.2 ± 12.1 mm VAS) after treatment. No significant change was noted (84.5 ± 5.8 mm VAS and 83.5 ± 8.9 mm VAS, respectively) in group 2. Conclusions: TENS was found to be effective and rapid in reducing pain during emergency transport of patients with acute low back pain and should be considered due to its ease of use and lack of side effects in the study population.     

Is Spinal Cord Stimulation an Effective Treatment Option for Discogenic Pain?

Introduction: In a prospective observational study conducted in an urban pain management center, we evaluated whether spinal cord stimulation (SCS) is effective in relieving discogenic pain of IDD origin. Methods: Thirteen patients with intractable discogenic low back pain were enrolled. Four patients never underwent permanent implantation due to insurance denial, medical reasons or failed trial and served as a control group. Nine patients underwent SCS implantation (treatment group). All patients were followed for 12 months and assessed at each interval for pain (NRS), disability (ODI), and opioid use. Results: Nine patients completed the SCS trial with > 50% pain relief. The pretrial NRS score was 7.8 ± 0.5 mm in treated patients vs. 6.5 ± 1.7 mm in control patients. At 3, 6 and 12 months, the NRS was reduced to 2.9 ± 0.7 mm, 1.7 ± 0.5 mm, and 2.9 ± 0.5 mm, respectively in treated patients. NRS was unchanged in the control patients (6.5 ± 1.9 mm). The ODI score prior to the SCS trial in treated patients was 53.1 ± 3.4% vs. 54.0 ± 20.5 in control patients. At 3, 6 and 12 months the ODI scores were 39.0 ± 8.0%, 38.7 ± 4.6%, and 41.1 ± 3.9%, respectively in the treated patients, and 48.5 ± 29.5 at 12 months in control patients. In 6 patients receiving opioids prior to the SCS trial, average consumption was reduced by 69% (P = 0.036) over 12 months of therapy as compared with a 54% increase in the control patients. SCS usage was stable over the 12‐month study. Conclusions: The current study indicates that SCS may provide effective pain relief, improve disability, and reduce opioid usage in patients with discogenic pain.     

Peripheral Neurostimulation in Supraorbital Neuralgia Refractory to Conventional Therapy

▪ Abstract:   Supraorbital neuralgia has been identified as an infrequent cause of headache that may prove very difficult to control pharmacologically. Peripheral nerve stimulation using electrodes to stimulate the nerve segmentally responsible for the zone of pain may constitute a management alternative in such cases. We present the case of a patient with headache because of posttraumatic supraorbital neuralgia, refractory to medical treatment, with good analgesic control after peripheral nerve stimulation.
Peripheral nerve stimulation may be considered a safe, reversible treatment for patients with headache secondary to supraorbital neuralgia who respond poorly to pharmacological treatment, thus avoiding irreversible alternatives such as surgery. ▪     

Peripheral Nerve Field Stimulation for Intractable Post‐Thoracotomy Scar Pain not Relieved by Conventional Treatment

Peripheral nerve field stimulation (PNFS) is being applied in individual cases where conventional treatments have failed to control pain localized to limited dermatomal distribution. We applied PNFS for unrelieved post‐thoracotomy scar pain. Although spinal cord stimulation may have resulted in good coverage in the same dermatomal distribution, we chose the more peripheral approach to minimize the risk of complications, avoiding the potential neurologic sequelae associated with stimulation of the spinal cord. In summary, PNFS was effective in relieving post‐thoractomy pain refractory to conventional pain management suggesting great potential of PNFS as a treatment option for chronic surgical‐scar pain.     

Efficacy of percutaneous electrical nerve stimulation and therapeutic exercise for older adults with chronic low back pain: a randomized controlled trial

Chronic low back pain (CLBP) in older adults may be disabling and therapeutically challenging, largely because of the inefficacy and/or morbidity associated with traditional pain treatment. We conducted a randomized controlled trial in 200 men and women > or = age 65 with CLBP to evaluate the efficacy of percutaneous electrical nerve stimulation (PENS) with and without general conditioning and aerobic exercise (GCAE), for reducing pain and improving physical function. Participants were randomized to receive (1) PENS, (2) control-PENS (brief electrical stimulation to control for treatment expectancy), (3) PENS+GCAE, or (4) control-PENS+GCAE, twice a week for 6 weeks. All four groups experienced significantly reduced pain (range -2.3 to -4.1 on the McGill Pain Questionnaire short form), improved self-reported disability (range -2.1 to -3.0 on Roland scale) and improved gait velocity (0.04-0.07 m/s), sustained at 6 months. The GCAE groups experienced significantly fewer fear avoidance beliefs immediately post-intervention and at 6 months than non-GCAE groups. There were no significant side effects. Since brief electrical stimulation (i.e., control-PENS) facilitated comparably reduced pain and improved function at 6 months as compared with PENS, the exact dose of electrical stimulation required for analgesia cannot be determined. GCAE was more effective than PENS alone in reducing fear avoidance beliefs, but not in reducing pain or in improving physical function.     

核心肌群训练联合经皮神经电刺激治疗产后非特异性下背痛的疗效观察

目的：探讨核心肌群训练联合经皮神经电刺激(TENS)治疗产后非特异性下背痛（NLBP）的有效性。方法：选取2021年10月至2022年9月在首都医科大学附属北京妇产医院女性盆底功能障碍诊治中心就诊的产后NLBP患者共50例。采用随机数字表法分为观察组和对照组,各25例。对照组给予针对下背部肌筋膜触发点的TENS治疗,观察组在此基础上联合核心肌群训练。在治疗前、治疗后和随访4周后,分别采用视觉模拟评分法（VAS）、Oswestry功能障碍指数（ODI）以及爱丁堡产后抑郁量表 (EPDS)进行疗效评价。结果：治疗后2组VAS评分、ODI指数均明显低于治疗前（P＜0.05）,且观察组明显低于对照组（P＜0.05）。随访4周,对照组VAS评分、ODI指数明显高于治疗后（P＜0.05）,观察组VAS评分、ODI指数与治疗后比较无统计学差异。对照组治疗后EPDS评分与治疗前无统计学差异,而观察组治疗后及随访4周EPDS评分均显著低于治疗前（P＜0.05）。结论：核心肌群训练联合TNES可有效改善产后NLBP患者的疼痛、功能障碍以及抑郁情绪状态,减少NLBP的复发。     

电刺激对周围神经再生的影响

周围神经损伤是创伤中常见的并发症，促进周围神经损伤后的再生，恢复其功能已日益成为研究的重点。本文就周围神经损伤的病理变化、周围神经成功再生的条件、电刺激促进周围神经再生的实验及临床研究、电刺激促进周围神经再生的机理进行了综述。目前关于电刺激促进周围神经再生的效应已逐渐得到认可，但电刺激治疗周围神经损伤仍存在着很多未知领域，还需要进一步更深入的研究。