Peripheral neuromodulation for the treatment of refractory trigeminal neuralgia

The Relevance of Implanted Percutaneous Electrical Nerve Stimulation in Orthopedics Surgery: A Systematic Review

Background: Percutaneous peripheral nerve stimulation (PNS) is a form of neuromodulation that involves the transmission of electrical energy via metal contacts known as leads or electrodes. PNS has gained popularity in orthopedic surgery as several studies have supported its use as a pain control device for patients suffering from pain due to orthopedic pathologies involving the knee, shoulder, and foot. The purpose of this systematic review is to summarize the literature involving peripheral nerve stimulation in orthopedic surgery. The existing body of literature provides support for further research regarding the use of PNS in the management of knee pain, hip pain, shoulder pain, foot pain, and orthopedic trauma. Notably, the evidence for its efficacy in addressing knee and shoulder pain is present. Methods: This study was conducted following PRISMA guidelines. Seven hundred and forty-five unique entries were identified. Two blinded reviewers assessed each article by title and abstract to determine its relevance and categorized them as "include", "exclude", and "maybe". After a preliminary review was completed, reviewers were unblinded and a third reviewer retrieved articles labeled as "maybe" and those with conflicting labels to determine their relevance. Twenty-eight articles were included, and seven hundred and seventeen articles were excluded. Articles discussing the use of PNS in the field of orthopedic surgery in patients > 18 years of age after 2010 were included. Exclusion criteria included neuropathic pain, phantom limb pain, amputation, non-musculoskeletal related pathology, non-orthopedic surgery related pathology, spinal cord stimulator, no reported outcomes, review articles, abstracts only, non-human subjects. Results: A total of 16 studies analyzing 69 patients were included. All studies were either case series or case reports. Most articles involved the application of PNS in the knee (8) and shoulder (6) joint. Few articles discussed its application in the foot and orthopedic trauma. All studies demonstrated that PNS was effective in reducing pain. Discussion: Peripheral nerve stimulation can be effective in managing postoperative or chronic pain in patients suffering from orthopedic pathology. This systematic review is limited by the scarcity of robust studies with substantial sample sizes and extended follow up periods in the existing literature.

Bibliometric and Visual Analysis of the Scientific Literature on Percutaneous Electrical Nerve Stimulation (PENS) for Pain Treatment

Background: Percutaneous electrical nerve stimulation (PENS) is a minimally invasive peripheral neuromodulation approach implemented against chronic neuropathic and mixed pain. This bibliometric study aims to quantitatively evaluate the output of PENS for pain treatment in the scientific literature. The main purpose is to stimulate research in the field and bridge potential scientific gaps. Methods: Articles were retrieved from the Web of Science (WOS) database. The search key term was “percutaneous electrical nerve stimulation (All Fields) and pain (All Fields)”. Year of publication, journal metrics (impact factor and quartile, Q), title, document type, topic, and citations were extracted. The join-point regression was implemented to assess differences in time points for the publication output. The software tool VOSviewer (version 1.6.17) was used for the visual analysis. Results: One thousand three hundred and eighteen articles were included in the knowledge visualization process. A linear upward trend for annual new publications was found. Almost two-thirds of the documents were published in top-ranked journals (Q1 and Q2). The topic “efficacy” was prevalent (12.81%). Concerning article type, the search strategy yielded 307 clinical investigations (23.3%). Articles were cited 36,610 times with a mean of 42.4 citations per article. Approximately one-half of the articles were cited less than 23 times in a range of 21 years. The semantic network analysis for keywords found eight clusters. The analysis of collaborative efforts among researchers showed five thematic clusters including 102 authors with a minimum of five documents produced in collaborations. Most partnerships involved the United States, England, and Germany. Conclusions: despite the upward trend in the number of publications on the subject and the publication of articles in top-ranked journals, there is a need to increase scientific collaborations between researchers and institutions from different countries.

Real world experience with minimally invasive wireless percutaneous neuromodulation in a tertiary care centre

Background

Wireless percutaneous nerve stimulation (PNS) for chronic pain is rapidly evolving in the ever expanding neuromodulation paradigm. Safety and lower risks with a potential of long-term analgesia cannot be over emphasised especially with the ongoing opioid pandemic. PNS with an implanted pulse generator (IPG) has also been shown to provide good benefit, without often unpleasant widespread paraesthesia from conventional spinal cord stimulators.

Aim and Methods

We retrospectively extracted data on all wireless PNS implants in our highly specialised pain neuromodulation centre since initiation of wireless PNS service in August 2019. Patient demographics, pain history, analgesic intake and details on implant follow-up data within 1 year post-implant including pain relief, EuroQol-5 Dimension (EQ-5D) and Patients' Global Impression of Change (PGIC) scores were extracted. The cases are presented in a narrative format.

Result

A total of five patients were implanted with wireless (Stimwave^®) PNS from August 2019 to February 2020. Neuropathic pain was the most common presenting diagnosis. All patients showed >50% pain relief at 3 months. EQ-5D and PGIC did not show any improvement in the subjects. Two of the patients managed to decrease their analgesics after implantation. Similar sustained benefits could not be demonstrated after 1 year.

Discussion

PNS can provide analgesia in appropriately selected cases. Naivety of the technique and procedure might cause some degree of uncertainty. External pulse generator with wireless transmission avoids IPG and tunnelling related side effects, but requires individualised special wearable technology to power the lead. Minimally invasive nature of the technique might be attractive and preferable for patients with complex medical issues, nickel allergy and poor general health who may otherwise be unsuitable for Spinal Cord Stimulation (SCS) with conventional hardware. Robust prospective controlled studies and RCTs in future might provide further insights on utility in other neuropathic pain diagnosis, long-term outcomes and acceptability compared to conventional SCS.

Petrobasal Vein: A Previously Unrecognized Vein Directly Connecting the Superior Petrosal Sinus with the Emissary Vein of the Foramen Ovale

BACKGROUND AND PURPOSE

The superior petrosal sinus terminates anteriorly at the cavernous sinus and posteriorly at the transverse sinus. Venous variations directly connecting the superior petrosal sinus and the emissary veins of the foramen ovale are not well-recognized. We present a connecting vein, provisionally named the petrobasal vein.

MATERIALS AND METHODS

Biplane cerebral angiography of the bilateral internal carotid arteries and the vertebral artery acquired in 267 patients was retrospectively reviewed by 2 neuroradiologists with special interest in the existence and course of the petrobasal vein.

RESULTS

The petrobasal vein was observed to lie anterior-posteriorly on the superior surface of the petrosal bone and connected to the midportion of the superior petrosal sinus and the emissary veins of the foramen ovale in 41 patients (15%) and sides (7.9%); it drained into the pterygoid plexus. The petrobasal vein was observed on VAG in 21 patients, on ICAG alone in 8 patients (9 sides), on both VAG and ICAG in 12 patients, and on ICAG in 1 patient. In the patients in whom the petrobasal vein was visualized on the ICAs, the superficial middle cerebral vein drained into a combination of the pterygoid plexus via the emissary veins of the foramen ovale and the superior petrosal sinus.

CONCLUSIONS

The petrobasal vein, an unknown vein directly connecting the superior petrosal sinus and the emissary veins of the foramen ovale and draining into the pterygoid plexus, can occasionally be identified on cerebral angiography as a variant drainage route from the cerebellum and brainstem veins and/or from the superficial middle cerebral vein. The petrobasal vein is thought to be a remnant of the primitive tentorial sinus.

Percutaneous Electrical Nerve Stimulation (PENS) as a Rehabilitation Approach for Reducing Mixed Chronic Pain in Patients with Musculoskeletal Disorders

“Mixed pain” is a term recently introduced to define the overlapping of nociceptive, neuropathic and nociplastic pain. To date, it has been reported that pharmacological treatments might have a modest effectiveness on patients affected by mixed chronic pain, with detrimental consequences in terms of disability, physical function and health-related quality of life. In this scenario, Percutaneous Electrical Nerve Stimulation (PENS), a mini-invasive neuromodulation technique, has been recently suggested as a promising approach for the complex management of mixed pain in musculoskeletal disorders. Albeit PENS showed to be effective in reducing unspecified pain in several chronic pain conditions, there is still a lack of evidence in the literature about its role in the management of neuropathic or mixed pain not responsive to pharmacological treatments. Therefore, by the present scoping review, we portray the potential effects of PENS in the multidisciplinary and multidimensional management of mixed chronic pain in patients with musculoskeletal disorders.

Peripheral Nerve Stimulation and Clinical Outcomes: A Retrospective Case Series

PURPOSE

Peripheral nerve stimulation (PNS) is a rapidly expanding field within neuromodulation; however, there is limited data on therapeutic efficacy. This study describes the indications and clinical outcomes for patients undergoing PNS for chronic pain states.

PATIENTS AND METHODS

This is a retrospective case series of adults undergoing PNS implantation from 2004 to 2017 at an academic medical center. The primary outcomes were changes in numeric rating scale (NRS) pain scores, opioid utilization in oral morphine milligram equivalent (MME), and self-reported patient functioning at 6 months postoperatively. Infectious and device-related complications were also assessed.

RESULTS

A total of 72 patients underwent PNS implantation, including 59 patients that received a preceding PNS trial (59/78; 76% progression rate) and 13 that did not receive a PNS trial. The most common indication for stimulation was occipital neuralgia (47%) followed by lower-extremity neuropathies (17%). PNS implantation was associated with 6-month reductions in pain scores (7 [6, 8] baseline vs. 4 [2, 5] 6 months; P < 0.001) and opioid utilization (eg, median 60 [31, 104] vs. 18 [0, 52] MME among those with baseline opioid use; P < 0.001). Median functional improvement was 73% (50%, 88%). Seven patients (10%) suffered a postoperative surgical site infection at a median of 50 (30, 124) days, of which five devices were removed.

CONCLUSION

Peripheral nerve stimulation was associated with reduced pain scores, lower opioid utilization, and improved patient function at 6 months. These data support PNS as a potentially effective nonopioid analgesic modality in chronic pain, though prospective multicenter evaluation is warranted to evaluate longer-term outcomes.

Peripheral trigeminal branch stimulation for refractory facial pain: A single-center experience

OBJECTIVE

Facial pain refractory to medical treatments may benefit from neurosurgical interventions. Only a few studies have reported on the efficacy of peripheral trigeminal stimulation and more specifically supraorbital nerve (SON) and infraorbital nerve (ION) stimulation for the treatment of facial pain.

PATIENTS AND METHODS

In the present study, we identified all patients at our institution who underwent SON and/or ION stimulation for treatment of facial pain due to post-herpetic, traumatic or idiopathic etiology. Relevant pre and post-operative outcomes were analyzed.

RESULTS

We identified 15 patients who underwent SON and/or ION stimulation. Among them, 12 (80 %) endorsed >50 % pain relief during the trial stimulation period. After a median follow-up of 5.8 months with permanent implantation, 1 patient (8.3 %) was diagnosed with lead erosion and IPG migration, two patients had lead infections (16.7 %) and one (8.3 %) had wound dehiscence. No lead migrations were identified during the long-term follow-up. The VAS score showed a statistically significant reduction from a median pre-operative score of 7 to a post-operative score of 1.8 (p = 0.011), which corresponded to a 74.3 % average pain reduction.

CONCLUSION

SON and/or ION stimulation can be an effective treatment for intractable facial pain due to post-herpetic, traumatic or idiopathic etiology; however the complication rate is relatively high. Future prospective studies with longer follow-up periods are warranted.

Pain Management in Multiple Sclerosis: a Review of Available Treatment Options

PURPOSE OF REVIEW

Multiple Sclerosis (MS) is a chronic autoimmune disease with no curative treatment available. While recent years have ushered in many effective new disease-modifying therapies for MS, they have not obviated the need for symptomatic treatments for MS-related pain. In this review, we discuss available approaches to control pain, which is one of the most common complaints MS patients have.

RECENT FINDINGS

The most recent research in this topic is directed towards non-pharmacologic interventions including water exercises, yoga and cannabis. More trials are being conducted on neuromodulation for MS-related neuropathic pain, including transcutaneous electrical nerve stimulation (TENS) and transcranial direct current stimulation (tDCS). Pain control for MS patients is challenging, considering the progressive and relapsing remitting nature of the disease, however, it is a very important aspect of it's management, as it improves mobility, exercise tolerance, concomitant depression and overall quality of life. Future research should focus on the use of neuromodulation in controlling MS pain.

Objective Assessment of Lingual Nerve Microsurgical Reconstruction

Lingual nerve (LN) injury is one of the most serious consequences of oral surgery. Prompt microsurgical reconstruction of the nerve can alleviate most of those symptoms leading to satisfactory functional recovery.Thirty-five patients with partial to complete LN injury underwent surgery in the period between January 2006 and May 2015. All patients underwent a preoperative clinical and neurological evaluation with the assessment of lingual tactile and pain sensory thresholds and masseteric inhibitory reflex.All patients underwent explorative surgery and direct microneurorrhaphy of distal and proximal stumps in case of complete lesion, while the removal of traumatic neuroma and the following microneurorrhaphy of distal and proximal stumps of the injured nerve was performed in case of incomplete lesion. Nerve grafting has always been avoided because of distal stump mobilization obtained by severing the submandibular branch of the LN.All patients but 1 exhibited good recovery of tongue sensation, never complete, both clinically and electrophysiologically: recovery of the excitability of masseteric inhibitory reflex suppression components SP1 and SP2 was observed, often with increased latencies but consistent with a functional recovery.All patients feeling pain preoperatively experienced complete relief of algic symptoms.The early microsurgical approach is the most suitable choice for the treatment of LN injuries.

Neuromodulation and Devices in Trigeminal Neuralgia

PREMISE

Trigeminal neuralgia is a severe facial pain disorder that has been studied for decades. Classical trigeminal neuralgia (CTN) is either idiopathic or caused by neurovascular compression. The related painful trigeminal neuropathies are often secondary to other causes, such as multiple sclerosis or trauma.

PROBLEM

Therapies for trigeminal neuralgia and neuropathy have often been pharmacologic or surgical. Pharmacologic therapies are not effective in some cases and often cause side effects, some substantial. Surgery can have comorbidity (such as anesthesia dolorosa, or painful differentiation of the affected nerve distribution) and also is not always effective. There is a desire, as in all chronic conditions, to find effective treatments with minimal morbidity and side effects.

POTENTIAL SOLUTIONS

We review several devices including neuromodulation, ranging in invasiveness, for treatment of trigeminal neuralgia and neuropathy. We review existing data on sphenopalatine ganglion blocks, transcranial magnetic stimulation, transcortical direct stimulation, deep brain stimulation, spinal cord stimulation, peripheral nerve stimulation, and transcutaneous electrical stimulation for CTN and pain trigeminal neuropathies. We also offer hope for further research in this area with the goal of discovering a device that can provide treatment for many with few side effects and minimal morbidity.

Neuroprotective Effects of Trigeminal Nerve Stimulation in Severe Traumatic Brain Injury

Following traumatic brain injury (TBI), ischemia and hypoxia play a major role in further worsening of the damage, a process referred to as 'secondary injury'. Protecting neurons from causative factors of secondary injury has been the guiding principle of modern TBI management. Stimulation of trigeminal nerve induces pressor response and improves cerebral blood flow (CBF) by activating the rostral ventrolateral medulla. Moreover, it causes cerebrovasodilation through the trigemino-cerebrovascular system and trigemino-parasympathetic reflex. These effects are capable of increasing cerebral perfusion, making trigeminal nerve stimulation (TNS) a promising strategy for TBI management. Here, we investigated the use of electrical TNS for improving CBF and brain oxygen tension (PbrO2), with the goal of decreasing secondary injury. Severe TBI was produced using controlled cortical impact (CCI) in a rat model, and TNS treatment was delivered for the first hour after CCI. In comparison to TBI group, TBI animals with TNS treatment demonstrated significantly increased systemic blood pressure, CBF and PbrO2 at the hyperacute phase of TBI. Furthermore, rats in TNS-treatment group showed significantly reduced brain edema, blood-brain barrier disruption, lesion volume, and brain cortical levels of TNF-α and IL-6. These data provide strong early evidence that TNS could be an effective neuroprotective strategy.

Review of Recent Advances in Peripheral Nerve Stimulation (PNS)

Peripheral nerve stimulation (PNS) for the treatment of chronic pain has become an increasingly important field in the arena of neuromodulation, given the ongoing advances in electrical neuromodulation technology since 1999 permitting minimally invasive approaches using an percutaneous approach as opposed to implantable systems. Our review aims to provide clinicians with the recent advances and studies in the field, with specific emphasis on clinical data and indications that have been accumulated over the last several years. In addition, we aim to address key basic science studies to further emphasize the importance of translational research outcomes driving clinical management.

Diagnosis and Management of Childhood Headache

Headache is one of the most common chief complaints seen in the pediatrician's office. Oftentimes, identifying the etiology of headache and differentiating primary and secondary causes can present a diagnostic conundrum. Understanding the most common causes of primary and secondary headache is vital to making a correct diagnosis. Here we review the typical presentations of the most common primary headache disorders and the approach to evaluation of the pediatric patient presenting with headache. Diagnostic workup, including the key features to elicit on physical examination, when to order head imaging, and the use of other ancillary tests, is discussed. Current treatment modalities and their indications are reviewed. We will also describe some of the new, emerging therapies that may alter the way we manage headache in the pediatric population. Headache can, at times, be a frustrating symptom seen in the pediatrician's office, but here we hope to better elucidate the approach to evaluation, management, and treatment as well as provide some hope in regards to more effective upcoming therapies.