Novel technique for trialing peripheral nerve stimulation: ultrasonography-guided StimuCath trial

Wireless Peripheral Nerve Stimulation for The Upper Limb: A Case Report

Peripheral neuro-stimulation (PNS) has been proved to be effective for the treatment of neuropathic pain as well as other painful conditions. We discuss two approaches to PNS placement in the upper extremity. The first case describes a neuropathic syndrome after the traumatic amputation of the distal phalanx of the fifth digit secondary to a work accident with lack of responsiveness to a triple conservative therapy. An upper arm region approach for the PNS was chosen. The procedure had a favorable outcome; in fact, after one month the pain symptoms were absent (VAS 0) and the pharmacological therapy was suspended. The second case presented a patient affected by progressive CRPS type II in the sensory regions of the ulnar and median nerve in the hand, unresponsive to drug therapy. For this procedure, the PNS device was implanted in the forearm. Unfortunately, in this second case the migration of the catheter affected the effectiveness of the treatment. After examining the two cases in this paper, we changed our practice and suggest the implantation of PNS for radial, median and/or ulnar nerve stimulation in the upper arm region, which has significant advantages over the forearm region.

Neuromodulation using a hybrid technique of combined perineural local anesthetic and nerve stimulation in six challenging clinical scenarios

PURPOSE

Postamputation pain is challenging because of complex mechanisms involving a multitude of pain pathways and psychological factors. This patient population also tends to have extensive comorbidities with or without a background of chronic pain. Electrical neuromodulation such as peripheral nerve stimulation has gained traction in the realm of chronic pain. Recently, the off-label use of hybrid perineural nerve stimulation in combination with locoregional block via the stimulating nerve block catheter has been described in single-center case reports.

CLINICAL FEATURES

Herein, we present a case series of six patients from two different Canadian hospitals using such a hybrid technique in three different clinical scenarios. These scenarios were (1) local anesthetic dose minimization in the presence of multiple nerve block catheters, (2) analgesia augmentation when local anesthetic alone is insufficient, and (3) provision of an analgesic adjunct as part of a multimodal regimen. A stimulating sciatic nerve block catheter was inserted under ultrasound and nerve stimulation guidance for these cases. Patients tended to experience pain on the subsequent postoperative days whereby the off-label use of nerve stimulation successfully reduced their pain score and stabilized or decreased their opioid consumption or minimized the need to increase the local anesthetic dose when doing so could have precipitated local anesthetic toxicity.

CONCLUSION

Our case series supports the feasibility of using a combination of low-frequency perineural stimulation and local anesthetic infusion via a single perineural nerve block catheter to manage challenging postamputation pain.

Upper-Extremity Peripheral Nerve Stimulators

Chronic pain conditions are some of the most challenging problems upper-extremity surgeons face and often require a multimodal approach including neuromodulation. Peripheral nerve stimulation (PNS) is one of these modalities, delivering electrical stimulation to peripheral axons to modulate the spinal cord and block out nociceptive signals from the extremity. This blockade leads to long-lasting effects in both the peripheral and central nervous systems. Not only does PNS decrease peripheral pain signals but it also decreases the peripheral inflammatory response and assists with central nervous system plasticity for long-term pain control. Although PNS was initially developed in the 1960s, it has been underrepresented in the literature largely due to the advent of spinal cord stimulation and the lack of Food and Drug Administration-approved hardware for PNS. However, for upper-extremity pain, PNS provides notable benefits over spinal cord stimulation devices, as PNS allows for safer, more specific, and often more effective pain control. As clinicians attempt to limit narcotic use, therapies such as PNS have been revisited and are gaining popularity. We present a narrative review of PNS; discuss its mechanism of action, indications, and surgical technique; and provide a summary of the available literature for the upper-extremity surgeon. Peripheral nerve stimulation offers a solution for chronic, debilitating pain recalcitrant to other treatment modalities.

Feasibility of Combining Nerve Stimulation and Local Anesthetic Infusion to Treat Acute Postamputation Pain: A Case Report of a Hybrid Technique

Pain following amputation is often poorly controlled despite the use of nerve blocks. We describe a novel pain management approach in a 56-year-old woman with episodes of poorly controlled pain following below-knee amputation despite a multimodal analgesic regimen with continuous sciatic nerve block. Effective analgesia was observed during those episodes when the nerve block catheter was briefly stimulated at low frequency using a nerve stimulator designed for regional anesthesia procedural guidance. This case report explains the utilization and rationale of this hybrid technique of combined peripheral nerve stimulation and locoregional analgesia via perineural nerve block catheters to augment analgesia.

Pain management using a novel hybrid technique of perineural stimulation combined with regional anaesthesia through a stimulating perineural catheter for below knee amputation

Pain after amputation can be difficult to manage due to its complex aetiology. A multimodal approach to analgesia, including regional anaesthetic techniques, is advised. However, optimal pain management cannot always be achieved, and high doses of opioid analgesics may contribute to adverse effects. We describe the management of an elderly patient with significant co-morbidities undergoing below knee amputation. Pre-operatively, a popliteal sciatic stimulating perineural catheter and a femoral non-stimulating perineural catheter were placed. When pain control was suboptimal on the first postoperative day, a combination of local anaesthetic and a brief period of peripheral nerve stimulation through the sciatic stimulating perineural catheter was used to augment pain control, thereby avoiding additional opioid use. Although nerve stimulation utilising specialised equipment, such as percutaneous stimulator electrodes, has been previously described in acute pain medicine, we demonstrate the use of a novel hybrid technique which combines nerve stimulation through a perineural catheter and local anaesthetic. Further research is warranted to explore the utility of this neuromodulation technique in clinical practice.

Translational Approaches to Electrical Stimulation for Peripheral Nerve Regeneration

BACKGROUND

Achieving functional repair after peripheral nerve injury (PNI) remains problematic despite considerable advances in surgical technique. Therein, questions lie regarding the variable capacity of peripheral nerves to regenerate based on environmental influence. In-depth analyses of multiple therapeutic strategies have ensued to overcome these natural obstacles. Of these candidate therapies, electrical stimulation has emerged a frontrunner. Extensive animal studies have reported the ability of brief intraoperative electrical stimulation (BES) to enhance functional regeneration after PNI. Despite these reports, the exact mechanisms by which BES enhances regeneration and its effects on long nerve lesions are largely unknown. Indeed, clinical translation of this seemingly simple therapeutic has not been so simple, but a few studies performed in humans have yielded highly encouraging results.

OBJECTIVE

We aimed to help bridge this translational gap by presenting the latest clinical trials on electrical stimulation for PNIs in combination with relevant etiologies, treatments and nonclinical findings.

METHODS

To do so, a systematic search was performed on PubMed, IEEE, and Web of Science databases up to February 2020 using keywords significant to our study. References of each manuscript were screened for additional manuscripts of relevance to our study.

RESULTS

We found multiple BES clinical studies reporting enhanced functional recovery or increased nerve regeneration. Although improved outcomes were reported, high variability after BES is seen between and within species likely due to injury severity, location and timeline along with other factors.

CONCLUSION

Further clinical studies and introduction of novel delivery platforms are vital to uncover the true regenerative potential of electrical stimulationtherapy.

Refractory neuropathic pain from a median nerve injury: spinal cord or peripheral nerve stimulation? A case report

Spinal cord stimulation (SCS) is the most frequently used neuromodulation technique even for neurogenic pain from a peripheral nerve injury although peripheral nerve stimulation (PNS) has been designed for this purpose. PNS appears less invasive than SCS or deep brain stimulation. It provides greater and specific target coverage and it could be more cost-effective than SCS because low electrical stimulation is exclusively delivered to the precise painful territory. We report a case of excellent result following median nerve stimulation at arm level after SCS failure and a 10-year history of intense pain. PNS would certainly have been considered much earlier if it was accepted and reimbursed by the Belgium National Insurance. PNS is a safe, simple, and efficient technique available for decades but it is still considered as experimental and underemployed. Belgian National Insurance fears an explosion of indications on neuromodulation if PNS was reimbursed. We consider that PNS aside SCS and other neuromodulation techniques should be made available in Belgium in case of peripheral chronic neuropathic pain.

Neuromodulation in headache and craniofacial neuralgia: guidelines from the Spanish Society of Neurology and the Spanish Society of Neurosurgery

INTRODUCTION

Numerous invasive and non-invasive neuromodulation devices have been developed and applied to patients with headache and neuralgia in recent years. However, no updated review addresses their safety and efficacy, and no healthcare institution has issued specific recommendations on their use for these 2 conditions.

METHODS

Neurologists from the Spanish Society of Neurology's (SEN) Headache Study Group and neurosurgeons specialising in functional neurosurgery, selected by the Spanish Society of Neurosurgery (SENEC), performed a comprehensive review of articles on the MEDLINE database addressing the use of the technique in patients with headache and neuralgia.

RESULTS

We present an updated review and establish the first set of consensus recommendations of the SEN and SENC on the use of neuromodulation to treat headache and neuralgia, analysing the current levels of evidence on its effectiveness for each specific condition.

CONCLUSIONS

Current evidence supports the indication of neuromodulation techniques for patients with refractory headache and neuralgia (especially migraine, cluster headache, and trigeminal neuralgia) selected by neurologists and headache specialists, after pharmacological treatment options are exhausted. Furthermore, we recommend that invasive neuromodulation be debated by multidisciplinary committees, and that the procedure be performed by teams of neurosurgeons specialising in functional neurosurgery, with acceptable rates of morbidity and mortality.

Evolving Techniques and Indications in Peripheral Nerve Stimulation for Pain

Peripheral nerve stimulation is the direct electrical stimulation of named nerves outside the central neuraxis to alleviate pain in the distribution of the targeted peripheral nerve. These treatments have shown efficacy in treating a variety of neuropathic, musculoskeletal, and visceral refractory pain pathologies; although not first line, these therapies are an important part of the treatment repertoire for chronic pain. With careful patient selection and judicious choice of stimulation technique, excellent results can be achieved for a variety of pain etiologies and distributions. This article reviews current and past practices of peripheral nerve stimulation and upcoming advancements in the field.

Median nerve stimulation induces analgesia via orexin-initiated endocannabinoid disinhibition in the periaqueductal gray

Adequate pain management remains an unmet medical need. We previously revealed an opioid-independent analgesic mechanism mediated by orexin 1 receptor (OX1R)-initiated 2-arachidonoylglycerol (2-AG) signaling in the ventrolateral periaqueductal gray (vlPAG). Here, we found that low-frequency median nerve stimulation (MNS) through acupuncture needles at the PC6 (Neiguan) acupoint (MNS-PC6) induced an antinociceptive effect that engaged this mechanism. In mice, MNS-PC6 reduced acute thermal nociceptive responses and neuropathy-induced mechanical allodynia, increased the number of c-Fos-immunoreactive hypothalamic orexin neurons, and led to higher orexin A and lower GABA levels in the vlPAG. Such responses were not seen in mice with PC6 needle insertion only or electrical stimulation of the lateral deltoid, a nonmedian nerve-innervated location. Directly stimulating the surgically exposed median nerve also increased vlPAG orexin A levels. MNS-PC6-induced antinociception (MNS-PC6-IA) was prevented by proximal block of the median nerve with lidocaine as well as by systemic or intravlPAG injection of an antagonist of OX1Rs or cannabinoid 1 receptors (CB1Rs) but not by opioid receptor antagonists. Systemic blockade of OX1Rs or CB1Rs also restored vlPAG GABA levels after MNS-PC6. A cannabinoid (2-AG)-dependent mechanism was also implicated by the observations that MNS-PC6-IA was prevented by intravlPAG inhibition of 2-AG synthesis and was attenuated in Cnr1 ^-/- mice. These findings suggest that PC6-targeting low-frequency MNS activates hypothalamic orexin neurons, releasing orexins to induce analgesia through a CB1R-dependent cascade mediated by OX1R-initiated 2-AG retrograde disinhibition in the vlPAG. The opioid-independent characteristic of MNS-PC6-induced analgesia may provide a strategy for pain management in opioid-tolerant patients.