Peripheral Nerve Stimulation Research Articles

"Knowing It Before Blocking It," the ABCD of the Peripheral Nerves: Part C (Prevention of Nerve Injuries).

"A clever person solves the problem. A wise person avoids it" (Albert Einstein). There is no convincing evidence that any modality 100% effectively prevents nerve injury. The risk of nerve injury remains the same even with the ultrasound due to limitations in the resolution of images and inter-operator and inter-patient differences. In a nutshell, caution is required when dealing with precious nerves in the perioperative period, either during peripheral nerve blocks (PNBs), patient positioning, or surgery. Identifying pre-existing nerve injury, either due to trauma or an existing neuropathy, and preventing further nerve injury should be an important goal in providing safe regional anesthesia (RA). Multimodal monitoring is key to avoiding multifactorial nerve injuries. The use of triple guidance (ultrasound + peripheral nerve stimulator + injection pressure monitor) during PNBs further improves the safety of RA. The ultrasound helps in real-time visualization of the nerve, needle, and drug spread; the peripheral nerve stimulator helps confirm the target nerves; and the injection pressure monitor helps avoid nerve injury. Such multimodalities can also give the confidence to administer PNB without risk of nerve injury. This article is part of the comprehensive overview of the essential understanding of peripheral nerves before blocking them. It describes various preventive measures to avoid peripheral nerve injuries while administering PNBs. It will help readers understand the importance of prevention in each step to avoid perioperative PNIs.

High frequency alternating current neurostimulation decreases nocifensive behavior in a disc herniation model of lumbar radiculopathy

BackgroundThe purpose of this study was to evaluate if kilohertz frequency alternating current (KHFAC) stimulation of peripheral nerve could serve as a treatment for lumbar radiculopathy. Prior work shows that KHFAC stimulation can treat sciatica resulting from chronic sciatic nerve constriction. Here, we evaluate if KHFAC stimulation is also beneficial in a more physiologic model of low back pain which mimics nucleus pulposus (NP) impingement of a lumbar dorsal root ganglion (DRG).MethodsTo mimic a lumbar radiculopathy, autologous tail NP was harvested and placed upon the right L5 nerve root and DRG. During the same surgery, a cuff electrode was implanted around the sciatic nerve with wires routed to a headcap for delivery of KHFAC stimulation. Male Lewis rats (3 mo., n = 18) were separated into 3 groups: NP injury + KHFAC stimulation (n = 7), NP injury + sham cuff (n = 6), and sham injury + sham cuff (n = 5). Prior to surgery and for 2 weeks following surgery, animal tactile sensitivity, gait, and static weight bearing were evaluated.ResultsKHFAC stimulation of the sciatic nerve decreased behavioral evidence of pain and disability. Without KHFAC stimulation, injured animals had heightened tactile sensitivity compared to baseline (p < 0.05), with tactile allodynia reversed during KHFAC stimulation (p < 0.01). Midfoot flexion during locomotion was decreased after injury but improved with KHFAC stimulation (p < 0.05). Animals also placed more weight on their injured limb when KHFAC stimulation was applied (p < 0.05). Electrophysiology measurements at end point showed decreased, but not blocked, compound nerve action potentials with KHFAC stimulation (p < 0.05).ConclusionsKHFAC stimulation decreases hypersensitivity but does not cause additional gait compensations. This supports the idea that KHFAC stimulation applied to a peripheral nerve may be able to treat chronic pain resulting from sciatic nerve root inflammation.

Magnetic Peripheral Nerve Stimulation (mPNS) for Chronic Pain.

To assess magnetic peripheral nerve stimulation (mPNS) for the treatment of chronic or chronic and intractable neuropathic pain with a retrospective review case series. Twenty-four patients with predominantly neuropathic post-traumatic or postoperative pain were treated as per protocol and followed for 3 months. Data were analyzed as an observational, one-armed, convenience sample. Graphical evidence backed up by a mixed model for repeated measures statistical analysis showed a highly significant reduction of pain at one month out from initial treatment with mPNS. At one month, there was a 3.8 average reduction in pre-pain scores using a visual analogue scale (VAS), and that relief was generally durable measured out to three months. Two-thirds of patients, deemed responders, showed an 87% reduction in pain. Opioid reduction was seen in 58.3% of responders as well. mPNS appears promising for the treatment of chronic or chronic and intractable neuropathic pain for many of the same indications as traditional electrical peripheral nerve stimulation (PNS). No invasive techniques or implants are needed for mPNS.

Peripheral Nerve Stimulation: A Comprehensive Guide.

Peripheral Nerve Stimulation: A Comprehensive Guide.

Vagus nerve stimulation: mechanisms and factors involved in memory enhancement.

Vagus nerve stimulation (VNS) has been recognized as a useful neuromodulation tool to target the central nervous system by electrical stimulation of peripheral nerves. Activation of the nucleus of the solitary tract (NTS) in the brainstem by vagal afferent nerve fibers allows for modulation of various higher order brain regions, including limbic and cerebral cortex structures. Along with neurological and psychiatric indications, clinical and preclinical studies suggest that VNS can improve memory. While the underlying mechanisms to improve memory with VNS involve brain areas, such as the prefrontal cortex and processes including alertness and arousal, here we focus on VNS-induced memory improvements related to the hippocampus, the main area implicated in memory acquisition. In addition, we detail research demonstrating that a targeted approach to VNS can modify memory outcomes and delve into the molecular mechanisms associated with these changes. These findings indicate that a greater understanding of VNS mechanisms while also considering stimulation parameters, administration site, timing in relation to training, and sex-specific factors, may allow for optimal VNS application to enhance memory.

Why Temporal Inference Stimulation May Fail in the Human Brain: A Pilot Research Study.

Temporal interference stimulation (TIS) aims at targeting deep brain areas during transcranial electrical alternating current stimulation (tACS) by generating interference fields at depth. Although its modulatory effects have been demonstrated in animal and human models and stimulation studies, direct experimental evidence is lacking for its utility in humans (in vivo). Herein, we directly test and compare three different structures: firstly, we perform peripheral nerve and muscle stimulation quantifying muscle twitches as readout, secondly, we stimulate peri-orbitally with phosphene perception as a surrogate marker, and thirdly, we attempt to modulate the mean power of alpha oscillations in the occipital area as measured with electroencephalography (EEG). We found strong evidence for stimulation efficacy on the modulated frequency in the PNS, but we found no evidence for its utility in the CNS. Possible reasons for failing to activate CNS targets could be comparatively higher activation thresholds here or inhibitory stimulation components to the carrier frequency interfering with the effects of the modulated signal.

Adaptive conductive electrotherapeutic scaffolds for enhanced peripheral nerve regeneration and stimulation

While peripheral nerve stimulation (PNS) has shown promise in applications ranging from peripheral nerve regeneration to therapeutic organ stimulation, clinical implementation has been impeded by various technological limitations, including surgical placement, lead migration, and atraumatic removal. We describe the design and validation of a platform technology for nerve regeneration and interfacing: adaptive, conductive, and electrotherapeutic scaffolds (ACESs). ACESs are comprised of an alginate/poly-acrylamide interpenetrating network hydrogel optimized for both open surgical and minimally invasive percutaneous approaches. In a rodent model of sciatic nerve repair, ACESs significantly improved motor and sensory recovery (p<0.05), increased muscle mass (p<0.05), and increased axonogenesis (p<0.05). Triggered dissolution of ACESs enabled atraumatic, percutaneous removal of leads at forces significantly lower than controls (p<0.05). In a porcine model, ultrasound-guided percutaneous placement of leads with an injectable ACES near the femoral and cervical vagus nerves facilitated stimulus conduction at significantly greater lengths than saline controls (p<0.05). Overall, ACESs facilitated lead placement, stabilization, stimulation, and atraumatic removal, enabling therapeutic PNS as demonstrated in small- and large-animal models. This work was supported by K. Lisa Yang Center for Bionics at MIT.

A Comprehensive Evaluation of Multiple Sclerosis-Related Fatigue with a Special Focus on Fatigability.

Fatigue is the most common and disabling symptom in multiple sclerosis (MS), being reported by 55% to 78% of patients with MS (PwMS). Etiology of MS-related fatigue remains poorly understood, but an increased neuromuscular fatigability (i.e., greater loss of torque during exercise) could contribute to this phenomenon. This study aimed to characterize the correlates of MS-related fatigue in PwMS using a comprehensive group of physiological and psychosocial measures, with a particular focus on fatigability. Forty-two relapsing-remitting PwMS and 20 healthy subjects were recruited. PwMS were assigned in two groups (high (HF) and low (LF) fatigue) based on two fatigue questionnaires (Fatigue Severity Scale and Modified Fatigue Impact Scale). The main outcomes of this study are derived from incremental cycling completed to task failure (i.e., inability to pedal around 60 rpm). Maximal voluntary contraction (MVC), rating of perceived exertion, and central and peripheral parameters measured using transcranial magnetic and peripheral nerve stimulation were assessed in the knee extensor muscles before, during, and after the fatiguing task. Other potential correlates of fatigue were also tested. MVC torque decreased to a greater extent for the HF group than LF group after the third common stage of the incremental fatiguing exercise (-15.7% ± 6.6% vs -5.9% ± 13.0%, P < 0.05), and this occurred concurrently with a higher rating of perceived exertion for HF (11.8 ± 2.5 vs 9.3 ± 2.6, P < 0.05). Subjective parameters (depression, quality of life) were worse for HF compared with LF and healthy subjects ( P < 0.001). Moreover, MVC torque loss at the final common stage and maximal heart rate explained 29% of the variance of the Modified Fatigue Impact Scale. These results provide novel insight into the relationship between MS-related fatigue and fatigability among PwMS. The HF group exhibited greater performance fatigability, likely contributing to a higher perceived exertion than the LF group when measured during a dynamic task.

ID: 214897 Peripheral Nerve Stimulation for Refractory Complex Regional Pain Syndrome Type I to Avoid Amputation

Peripheral nerve and dorsal root ganglion stimulation (DRG-s) are effective treatment modalities for focal complex regional pain syndrome (CRPS) that is limited to one or two dermatomes1,2,3. When deciding on a neural target for stimulation, consideration is given to the location of pain, MRI labeling, charge burden of external or internal pulse generator, spinal hardware, and medical comorbidities. While a reduction in pain of fifty percent or greater is often deemed a satisfactory response in the treatment of chronic pain, we describe a case were the patient sought amputation of her limb in the hopes a prosthetic extremity would provide improved function. Despite the risk of post amputation pain, there are patients that seek amputation for advanced CRPS that is refractory to treatment4,5,6. We proceeded with peripheral nerve stimulation (PNS) in addition to her DRG-s system in effort to avoid her upcoming amputation.

ID: 223066 Peripheral Nerve Stimulation in Chronic Non-Surgical Joint Pain Patients: A Case Series

Peripheral nerve stimulation (PNS) modulates peripheral nerves to provide control of localized chronic pain conditions. Specific nerves involved in the transmission of localized pain are targeted using fluoroscopic or ultrasound guidance for the subcutaneous placement of wireless electrode leads. PNS is an emerging treatment modality for mostly lower extremity pain, but evidence-based guidance is lacking. Furthermore, most published reports are limited to individual case reports, and they do not address chronic joint pain. Here we provide a case series of 55 patients who underwent PNS for chronic shoulder, sacroiliac, knee, and ankle pain.

ID: 200399 Peripheral Brachial Plexus Nerve Stimulation in Coagulopathic Patient Who Responded to Median Nerve Modulation

Through the basis of Gate Control Theory first described by Gate and Melzack (1) as well as the advancement of ultrasound capabilities, Peripheral Nerve Stimulation (PNS) has emerged as a novel treatment modality for a variety of intractable pain conditions resistant to current, first-line therapies. One such condition includes Complex Regional Pain Syndrome (CRPS), which involves non-specific pain that is disproportionate in time or degree to the typical course of a specific trauma or lesion and often includes abnormal sensory, vasomotor, and/or trophic findings with a variable progression over time [2]. Given the challenges often faced by clinicians in treating CRPS, PNS is gaining greater utilization with the goal of decreasing pain and restoring function for patients suffering from this condition.

ID: 205697 Femoral Peripheral Nerve Stimulator for Chronic Hip Pain With Total Hip Arthroplasty: A Case Report

Chronic pain is a common cause of morbidity, significantly impacting quality of life.1 As medical practice steers away from narcotic use, providers have championed for opioid-sparing techniques such as peripheral nerve stimulation for safe and effective pain management. Peripheral nerve stimulation (PNS) is a minimally invasive procedure that has been reported to be effective for pain relief while improving quality of life, with few side effects present.2,3 It has also significantly decreased the need for opioid use. PNS has been used in acute postoperative pain, and chronic shoulder, knee, and back pain.1 There is limited literature in its use for chronic hip pain, especially after surgical intervention was done for the pain. Our case involved successful implantation of a femoral PNS in a patient with chronic hip pain after total hip arthroplasty was done for his pain relief.

ID: 216134 Treatment of Post-Amputation Pain With Wireless Peripheral Nerve Stimulation

Significant physical and psychological distress is experienced by patients who undergo limb amputation. Limb amputation can lead to post-amputation pain (PAP), which is categorized as either residual limb pain (RLP) or phantom limb pain (PLP) (1, 2). Patients are initially treated with conservative treatments to include rehabilitation and pharmacotherapy that often prove inadequate (3). Peripheral nerve stimulation (PNS) is an innovative treatment modality that has been effective for PAP patients by targeting maladaptive neuroplastic alterations via implantable stimulators (3, 5). However, conventional PNS systems are associated with challenges due to the need for implantation of bulky components and invasive surgical access (4, 5, 6). Wireless PNS is a less invasive solution for PAP while providing precise lead placements (5). The following case report describes one of the first patients to be treated with wireless peripheral nerve stimulation for post-amputation pain.

ID: 207779 Peripheral Nerve Stimulation for the Treatment of Chronic Knee Pain: A Retrospective Case Series

Peripheral nerve stimulation (PNS) is a promising novel treatment modality for the management of chronic knee pain.1,2 Multiple studies have suggested that PNS is effective in the treatment of post-surgical knee pain.3-5 Fewer data, however, exist to support the use of PNS in the pre-surgical setting. This investigation seeks to clarify the potential clinical utility of PNS for the treatment of chronic knee pain amongst patients who have failed conservative measures.

ID: 196299 Axillary Peripheral Nerve Stimulation for Severe Glenohumeral Osteoarthritis Not Amenable to Surgery: A Case Report

Glenohumeral osteoarthritis (OA) is a common cause of chronic shoulder pain in the elderly (1). When conservative management fails to provide adequate pain relief, total shoulder arthropathy (TSA) may be considered (1). If surgical treatment is not feasible due to poor surgical candidacy, there are currently limited non-surgical options for end-stage shoulder OA (1,2,3). Peripheral nerve stimulation (PNS) has been utilized successfully for refractory shoulder pain, even when the pain is secondary to degenerative joint disease (2,3).

ID: 204949 Peripheral Nerve Stimulation for Refractory Shoulder Pain: A Case Report

Peripheral Nerve Stimulation (PNS), used in the management of chronic focal pain, provides a viable therapeutic intervention for patients with chronic shoulder pain who have exhausted medical and surgical options.

ID: 222501 Early Outcomes From a Randomized Control Trial for the Treatment of Peripheral Neuralgia

A battery-free, peripheral nerve stimulation (PNS) system with a micro-implantable pulse generator (mIPG; Nalu Medical, Inc., Carlsbad, CA) delivers stimulation to peripheral nerves to treat chronic peripheral neuralgia. An ongoing, randomized clinical trial (RCT) was initiated to document the comparative effectiveness and safety of peripheral nerve stimulation plus conventional medical management (CMM; active arm) versus CMM alone (control arm) in the treatment of chronic, intractable peripheral neuralgia of post-traumatic or post-surgical origin.

ID: 204783 Placement of Genicular Nerve Peripheral Nerve Stimulator for Chronic Knee Pain

Peripheral nerve stimulation (PNS) is an evolving modality for treating different chronic pain conditions. The intervention was predicated on the gate theory of pain, which posits nociceptive and non-nociceptive inputs modulate the other's intensity in the dorsal horn of the spine. Although gate theory was one of the first explanations of PNS, competing theories now include overstimulation of c-fibers, exhaustion of neurotransmitters, fixed depolarization of afferent axons, and electrically induced changes to long term potentiation.1 No unified mechanism has been established, though the efficacy of PNS is evident.

ID: 205475 An Unfolding, Injectable Micro-Paddle for Efficient Spinal Cord Stimulation

Approximately 60% of all spinal cord stimulation (SCS) and peripheral nerve stimulation (PNS) doses for pain management are reduced by the 360° stimulation field limitations of the cylindrical percutaneous lead (CPL). With CPL, only 30% of the therapy dose is pointed towards the nerve target. [1] Poor dosing efficiency results in higher stimulation therapy amplitude, 2x higher recharge burden and more frequent battery replacement surgery. [2, 3] Multi-contact programming and novel high frequency waveforms further multiply these dosing inefficiencies. We demonstrate a self-opening injectable micro-paddle in cadavers and sheep. After deploying through a 13-gauge Tuohy needle, the lead self-opens to form a 4 mm wide micro-paddle with a unidirectional stimulation field. We performed fluoroscopy during deployment and benchmarked the retraction forces in comparison with cylindrical leads. We further developed a platinum-iridium surface processing which improves the charge injection density by 2x over conventional leads.

ID: 219222 Peripheral Nerve Stimulation for Refractory Plantar Fibromatosis Pain: A Case Report and Literature Review

41-year-old man was referred by orthopedics to the outpatient pain clinic with history of chronic bilateral plantar heel pain and a diagnosis of plantar fibromatosis following diagnostic ultrasound evaluation. He had failed numerous non-operative treatments including shoe wear modification, orthoses, physical therapy, acupuncture, shock wave therapy, ultrasound guided corticosteroid injection, and percutaneous needle tenotomy. Upon initial consultation, the patient endorsed a 5-year history of bilateral medial plantar heel pain, provoked with weight bearing activities. He denied paresthesias and weakness. Given his refractory symptoms joint the decision was made to proceed with a diagnostic block of his more symptomatic side with goal to pursue bilateral percutaneous 60-day peripheral nerve stimulator placement if he experienced a favorable response. Diagnostic target was the left tibial nerve just proximal to the medial malleolus and prior to its division into plantar and calcaneal branches. Diagnostic injectate consisted of 2cc 1% lidocaine and 5mg of dexamethasone for a total volume of 2.5cc. Patient rated his pain 8/10 prior to injection and 0/10 following. He subsequently underwent placement of dual peripheral nerve stimulators targeting the bilateral tibial nerves with implantation 5cm proximal to the medial malleoli. At 60 day follow up, the device was explanted. The patient was no longer tender with palpation of either foot. He reported 50% reduction compared to pre-operative pain, significant improvement in his quality of life and physical functioning, and a reduction in oral analgesic regimen. The patient is currently awaiting permanent stimulator placement.