Peripheral Nerve Stimulation With a High-Frequency Electromagnetic Coupled Powered Implanted Receiver at the Posterior Tibial Nerve for the Treatment of Chronic Pain in the Foot.

INTRODUCTION: Peripheral neuropathy has several causes, with diabetes being the most common. Conservative management may fail to control pain. Our study aimed at evaluating the use of peripheral nerve stimulation of the posterior tibial nerve for treating peripheral neuropathy. MATERIALS AND METHODS: This was an observational study of 15 patients who received peripheral nerve stimulation at the posterior tibial nerve to treat peripheral neuropathy. Outcomes measured were improvement of pain scores and Patient Global Impression of Change (PGIC) at 12 months compared with before the implant. RESULTS: Mean pain scores with the verbal rating scale were 3 ± 1.8 at >12 months compared with 8.6 ± 1.2 at baseline, a reduction of 65% (p < 0.001). Median satisfaction with the PGIC at >12 months was 7 of 7, with most subjects reporting a 6 (better) or a 7 (a great deal better). CONCLUSION: Peripheral nerve stimulation of the posterior tibial nerve can be a safe and effective modality for treating chronic pain symptoms related to peripheral neuropathy of the foot.

Supraorbital Nerve Stimulation for Facial Pain.

PURPOSE OF REVIEW: Chronic facial pain is considered one of the conditions that affect quality of daily life of patients significantly and makes them seek medical help. Intractable facial pain with failed trials of medical treatment and other pain management therapies presents a challenge for neurologists, pain specialists, and neurosurgeons. We describe the possibility of proposing peripheral nerve stimulation of the supraorbital nerves to treat patients with medically intractable facial pain. Stimulation of the supraorbital nerves is performed using percutaneously inserted electrodes that are positioned in the epi-fascial plane, traversing the course of the supraorbital nerves. The procedure has two phases starting with a trial by temporary electrodes that are inserted under fluoroscopic guidance and are anchored to the skin. This trial usually lasts for a few days to 2 weeks. If successful, we proceed to the insertion of a permanent electrode that is tunneled under the skin behind the ear toward the infraclavicular region in which we make a pocket for the implantable pulse generator. RECENT FINDINGS: This procedure has been used in multiple patients with promising results which was published in literature. Literature shows that it provides relief of medically intractable pain, without the need for destructive procedures or more central modulation approaches with a preferable safety profile compared to other invasive procedures. Supraorbital nerve stimulation is now considered a valid modality of treatment for patients with medically intractable facial pain and can be offered as a reliable alternative for the patients while discussing the proper plan of management.

Perioperative and anesthetic considerations for the management of neuromodulation systems.

The use of neuromodulation systems is increasing for the treatment of various pathologies ranging from movement disorders to urinary incontinence to chronic pain syndromes. While the type of neuromodulation devices varies, they are largely categorized as intracranial (eg, deep brain stimulation), neuraxial (eg, spinal cord stimulation, dorsal root ganglion stimulation, and intrathecal drug delivery systems), or peripheral (eg, sacral nerve stimulation and peripheral nerve stimulation) systems. Given the increasing prevalence of these systems in the overall population, it is important for anesthesiologists, surgeons, and the perioperative healthcare team to familiarize themselves with these systems and their unique perioperative considerations. In this review, we explore and highlight the various neuromodulation systems, their general perioperative considerations, and notable special circumstances for perioperative management.

Evidence-Based Treatment of Pain in Chemotherapy-Induced Peripheral Neuropathy.

PURPOSE OF REVIEW: Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating and often painful condition that occurs after administration of chemotherapeutic agents. The primary objective of this systematic review was to appraise the literature on conservative, pharmacological, and interventional treatment options for CIPN pain. RECENT FINDINGS: There is level I evidence supporting modest to moderate improvement in CIPN pain from duloxetine treatment, as well as short-term modest improvement from physical therapy and acupuncture. Although opioid and cannabis administration may provide short-term modest improvement, administration is commonly limited by side effects. Generally, most studies reported no clinical benefit from yoga, topical neuropathic agents, gabapentinoids, and tricyclic antidepressants. Evidence is currently equivocal for scrambler therapy and transcutaneous electrical nerve stimulation. Finally, evidence on neuromodulation options is limited to mostly case reports/series and one observational study highlighting moderate improvement with auricular nerve stimulation. This systematic review provides an overview of conservative, pharmacologic, and interventional treatment modalities for CIPN pain. Furthermore, it provides a level of evidence and degree of recommendation based on the United States Preventive Services Task Force (USPSTF) criteria for each specific treatment modality.

Peripheral Nerve Stimulation for Low Back Pain: A Systematic Review.

PURPOSE OF REVIEW: Low back pain (LBP) is a prevalent condition that is associated with diminished physical function, poor mental health outcomes, and reduced quality of life. Peripheral nerve stimulation (PNS) is an emerging modality that has been utilized to treat LBP. The primary objective of this systematic review is to appraise the level of evidence on the efficacy of PNS for treatment of LBP. RECENT FINDINGS: Twenty-nine articles were included in this systematic review, consisting of 828 total participants utilizing PNS as the primary modality for LBP and 173 participants using PNS as salvage or adjunctive therapy for LBP after SCS placement. Different modalities of PNS therapy were reported across studies, including conventional PNS systems stimulating the lumbar medial branch nerves, peripheral nerve field stimulation (PNFS), and restorative neuromuscular stimulation of the multifidus muscles. All studies consistently reported positive modest to moderate improvement in pain intensity with PNS therapy when comparing baseline pain intensity to each study's respective primary follow-up period. There was a very low GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) quality of evidence supporting this finding. Inconsistency was present in some comparative studies that demonstrated no difference between PNS therapy versus control cohorts (sham or SCS therapy alone), which therefore highlighted the potential for placebo effect. This systematic review highlights that PNS, PNFS, and neuromuscular stimulation may provide modest to moderate pain relief in patients with LBP, although evidence is currently limited due to risk of bias, clinical and methodological heterogeneity, and inconsistency in data.

Mechanism of Action of Peripheral Nerve Stimulation for Chronic Pain: A Narrative Review.

The use of stimulation of peripheral nerves to test or treat various medical disorders has been prevalent for a long time. Over the last few years, there has been growing evidence for the use of peripheral nerve stimulation (PNS) for treating a myriad of chronic pain conditions such as limb mononeuropathies, nerve entrapments, peripheral nerve injuries, phantom limb pain, complex regional pain syndrome, back pain, and even fibromyalgia. The ease of placement of a minimally invasive electrode via percutaneous approach in the close vicinity of the nerve and the ability to target various nerves have led to its widespread use and compliance. While most of the mechanism behind its role in neuromodulation is largely unknown, the gate control theory proposed by Melzack and Wall in the 1960s has been the mainstay for understanding its mechanism of action. In this review article, the authors performed a literature review to discuss the mechanism of action of PNS and discuss its safety and usefulness in treating chronic pain. The authors also discuss current PNS devices available in the market today.

Holistic Treatment Response: An International Expert Panel Definition and Criteria for a New Paradigm in the Assessment of Clinical Outcomes of Spinal Cord Stimulation.

BACKGROUND: Treatment response to spinal cord stimulation (SCS) is focused on the magnitude of effects on pain intensity. However, chronic pain is a multidimensional condition that may affect individuals in different ways and as such it seems reductionist to evaluate treatment response based solely on a unidimensional measure such as pain intensity. AIM: The aim of this article is to add to a framework started by IMMPACT for assessing the wider health impact of treatment with SCS for people with chronic pain, a "holistic treatment response". DISCUSSION: Several aspects need consideration in the assessment of a holistic treatment response. SCS device data and how it relates to patient outcomes, is essential to improve the understanding of the different types of SCS, improve patient selection, long-term clinical outcomes, and reproducibility of findings. The outcomes to include in the evaluation of a holistic treatment response need to consider clinical relevance for patients and clinicians. Assessment of the holistic response combines two key concepts of patient assessment: (1) patients level of baseline (pre-treatment) unmet need across a range of health domains; (2) demonstration of patient-relevant improvements in these health domains with treatment. The minimal clinical important difference (MCID) is an established approach to reflect changes after a clinical intervention that are meaningful for the patient and can be used to identify treatment response to each individual domain. A holistic treatment response needs to account for MCIDs in all domains of importance for which the patient presents dysfunctional scores pre-treatment. The number of domains included in a holistic treatment response may vary and should be considered on an individual basis. Physiologic confirmation of therapy delivery and utilisation should be included as part of the evaluation of a holistic treatment response and is essential to advance the field of SCS and increase transparency and reproducibility of the findings.

Use of Spinal Cord Stimulators in Patients With Pacemakers or Implantable Cardiac Defibrillators: A Review of Documented Accounts of Interference.

OBJECTIVES: To assess the currently available evidence regarding associations between spinal cord stimulator (SCS) lead type, clinical indications for device placement, and interference between SCSs and cardiac pacemakers (CPMs)/implantable cardioverter-defibrillators (ICDs). STUDY DESIGN: Review of case reports and original research studies assessing the interference between SCS and CPM/ICD. MATERIALS AND METHODS: PubMed and Cochrane databases were searched for articles commenting on the interference between SCS and CPM/ICD. The search criteria which generated the greatest number of relevant studies was (spinal cord stimulator AND [pacemaker OR implantable cardioverter defibrillator]). Additional, empiric review was conducted using JSTOR, ScienceDirect, and EBSCOhost databases; however, no additional eligible studies were identified. Data were extracted, summarized into tables, and quantitatively analyzed using LibreTexts and MedCalc software. RESULTS: There was no statistically significant interference observed between SCS and CPM/ICD devices in patients regardless of indication for SCS placement and SCS lead polarity. LIMITATIONS: Limited by variability of patient cases and variability in maximum frequency and amplitude of SCS devices tried in individual cases. Also limited by small sample size and the absence of a standard definition for device interference across studies. CONCLUSIONS: Interference between cardiac devices and SCSs is a rare occurrence. As there are currently no published guidelines, devices should be interrogated on a case-by-case basis in the SCS trial period (if implanted after cardiac device), during permanent implantation, and during scheduled follow-up visits. Peri-operative testing should include increasing the SCS settings to maximally tolerated levels with cardiac device set at its maximum sensitivity.

Radiofrequency Ablation of the Trochanteric Branches of the Femoral Nerve for the Treatment of Greater Trochanteric Syndrome.

BACKGROUND: Approximately 10-15% of the population over the age of 60 suffers from hip pain. Greater trochanteric pain syndrome (GTPS) is one of the most common diagnoses in patients with chronic hip pain, includes a number of disorders, and has a broad differential diagnosis. Conservative managements of GTPS, including pharmacologic interventions, physical therapy, chiropractic intervention, acupuncture, and more invasive techniques, such as intra-articular injections, commonly fail to provide patients with sufficient, long-term relief. While radiofrequency ablation (RFA) has been used to treat intra-articular hip pain in the past, there is little evidence for the feasibility of RFA for managing patients with GTPS. This case series builds on previous evidence that cooled radiofrequency ablation (CRF) of the trochanteric branch of the femoral nerve may offer patients with GTPS effective, safe, and lasting pain improvement. CASES: A series of eight patients with GTPS underwent CRF of the nervus females to the trochanter. CRF procedures were either targeted at the left, right, or bilateral nerves. CONCLUSION: This case series provides additional evidence for the safety and effectiveness of CRF of the nervus femoralis to the trochanter for offering long-term pain relief in patients with GTPS. All patients experienced at least two months of relief, with most patients experiencing ongoing relief from the procedure.

The Neurostimulation Appropriateness Consensus Committee (NACC): Recommendations on Best Practices for Cervical Neurostimulation.

INTRODUCTION: The International Neuromodulation Society convened a multispecialty group of physicians based on expertise with international representation to establish evidence-based guidance on the use of neurostimulation in the cervical region to improve outcomes. This Neurostimulation Appropriateness Consensus Committee (NACC) project intends to provide evidence-based guidance for an often-overlooked area of neurostimulation practice. MATERIALS AND METHODS: Authors were chosen based upon their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from 2017 (when NACC last published guidelines) to the present. Identified studies were graded using the US Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence was scant. RESULTS: The NACC examined the published literature and established evidence- and consensus-based recommendations to guide best practices. Additional guidance will occur as new evidence is developed in future iterations of this process. CONCLUSIONS: The NACC recommends best practices regarding the use of cervical neuromodulation to improve safety and efficacy. The evidence- and consensus-based recommendations should be utilized as a guide to assist decision making when clinically appropriate.

Peripheral Nerve Stimulation in Pain Management: A Systematic Review.

BACKGROUND: Peripheral nerve stimulation (PNS) has been increasingly used to manage acute and chronic pain. However, the level of clinical evidence to support its use is not clear. OBJECTIVES: To assess the clinical evidence of PNS in the treatment of acute or chronic pain. STUDY DESIGN: A systematic review of the efficacy and safety of PNS in managing acute or chronic pain. METHODS: Data sources were PubMed, Cochrane Library, Scopus, CINAHL Plus, Google Scholar, and reference lists. The literature search was performed up to December 2019. Study selection included randomized trials, observational studies, and case reports of PNS in acute or chronic pain. Data extraction and methodological quality assessment were performed utilizing Cochrane review methodologic quality assessment and Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment (IPM-QRB) and Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment for Nonrandomized Studies (IPM-QRBNR). The evidence was summarized utilizing principles of best evidence synthesis on a scale of 1 to 5. Data syntheses: 227 studies met inclusion criteria and were included in qualitative synthesis. RESULTS: Evidence synthesis based on randomized controlled trials (RCTs) and observational studies showed Level I and II evidence of PNS in chronic migraine headache; Level II evidence in cluster headache, postamputation pain, chronic pelvic pain, chronic low back and lower extremity pain; and Level IV evidence in peripheral neuropathic pain, and postsurgical pain. Peripheral field stimulation has Level II evidence in chronic low back pain, and Level IV evidence in cranial pain. LIMITATIONS: Lack of high-quality RCTs. Meta-analysis was not possible due to wide variations in experimental design, research protocol, and heterogeneity of study population. CONCLUSIONS: The findings of this systematic review suggest that PNS may be effective in managing chronic headaches, postamputation pain, chronic pelvic pain, and chronic low back and lower extremity pain, with variable levels of evidence in favor of this technique.

Treatment and Management of Loin Pain Hematuria Syndrome.

PURPOSE OF REVIEW: Loin pain hematuria syndrome (LPHS) is rare and seldom diagnosed, yet it has a particularly significant impact on those affected. This is a review of the latest and seminal evidence of the pathophysiology and diagnosis of LPHS and presents the typical clinical presentation and treatment options available. RECENT FINDINGS: LPHS is typically found in young women with characteristic symptoms, including severe recurrent flank pain and gross or microscopic hematuria. The majority of patients will experience crippling pain for many years without effective therapy, often requiring frequent use of narcotic medication. However, the lack of conclusive pathophysiology, in conjunction with the rarity of LPHS, has prohibited the development and trial of definitive treatment options. Nevertheless, in order to combat this rare but severe disease, management strategies have continued to evolve, ranging from conservative measures to invasive procedures. This review presents an overview of the current hypotheses on the pathophysiology of LPHS in addition to summarizing the management strategies that have been utilized. Only 30% of LPHS patients will experience spontaneous resolution, whereas the majority will continue to face chronic, crippling pain. Several methods of treatment, including invasive and non-invasive, may provide an improved outcome to these patients. Treatment should be individually tailored and multi-disciplinary in nature. Further research is required to further elucidate the pathophysiology and develop new, specific, treatment options.

Dorsal Root Ganglion Stimulation for the Treatment of Non-Complex Regional Pain Syndrome Related Chronic Pain Syndromes: A Systematic Review.

BACKGROUND: While the majority of indications and approvals for dorsal root ganglion stimulation (DRGS) are for the refractory management of complex regional pain syndrome (CRPS), emerging evidence has suggested that DRGS may be favorably used for a plethora of other chronic pain phenomena. Consequently, we aimed to characterize the use and efficacy of DRGS for these non-CRPS-related chronic pain syndromes. MATERIALS AND METHODS: A systematic review of clinical studies demonstrating the use of DRGS for non-CRPS-related chronic pain syndromes. The literature search was performed using PubMed, Cochrane Library, and CINAHL plus across August and September 2020. RESULTS: A total of 28 reports comprising 354 total patients were included in the analysis. Of the chronic pain syndromes presented, axial low back pain, chronic pelvic and groin pain, other peripheral neuropathies, and studies with multiple concomitant pain syndromes, a majority demonstrated >50% mean pain reduction at the time of last follow-up following DRGS. Physical function, quality of life (QOL), and lesser pain medication usage also were repeatedly reported to be significantly improved. CONCLUSIONS: DRGS continues to lack supportive evidence from well designed, high level studies and recommendations from consensus committee experts. However, we present repeated and consistent evidence from lower level studies showing success with the use of DRGS for various non-CRPS chronic pain syndromes in reducing pain along with increasing function and QOL from one week to three years. Due to such low-level, high bias evidence, we strongly encourage the continuation of high-level studies in order to provide a stronger foundation for the use of DRGS in non-CRPS chronic pain patients. However, it may be reasonable and appropriate to evaluate patients for DRGS candidacy on a case-by-case basis particularly if they manifest focal pain syndromes refractory to noninterventional measures and may not be ideal candidates for other forms of neuromodulation.

Impact of Lavender on Pain and Anxiety Levels Associated With Spine Procedures.

Background: To reduce pain and anxiety associated with interventional pain procedures, sedation is often used, with benzodiazepines, opioids, and propofol the most commonly used classes of drugs for sedation. However, patient coherence and ability to communicate procedural pain and abnormal sensations help prevent adverse outcomes. Therefore, discovering alternative therapies to mitigate the anxiety and pain associated with these procedures and to minimize risk is important. The aim of our study was to investigate whether lavender has an effect on pain and anxiety associated with lumbar epidural steroid injections and lumbar medial branch blocks. Methods: In this randomized controlled study, 54 subjects were randomly assigned to 1 of 3 intervention groups, and 46 patients were included in the final analysis: experimental lavender group (n=17), control almond oil group (n=15), and placebo sterile water group (n=14). Patients wore a mask infused with either lavender, almond oil, or water for 5 minutes prior to and during their procedure. Patients rated their anxiety using the State-Trait Anxiety Inventory prior to and after the procedure based on how they felt during the procedure. Patients rated their pain according to the numerical rating scale. Outcome measures were a comparison of pain among the 3 groups and a comparison of the change in anxiety before and after the procedure among the 3 groups. Results: The lavender group demonstrated the highest mean change in anxiety scores (9.9) compared to almond oil (5.3) and water (3.6) preprocedurally vs postprocedurally. The lavender group also reported the lowest mean pain level (3.8) compared to almond oil (5.6) and water (5.6). However, none of the differences between groups showed statistical significance at the P<0.05 level. Conclusion: Lavender may have a clinically beneficial effect on anxiety levels and pain reduction.

Anesthetic Considerations and Perioperative Management of Sacral Neuromodulators: Literature Review and Initial Recommendations.

OBJECTIVE: Sacral neuromodulation (SNM) is gaining increased integration in the realm of medicine. With increasing use, anesthetic and periprocedural considerations must be understood. The goal of this article is to review and consolidate available literature on device management in these settings. MATERIALS AND METHODS: Searches were preformed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Electronic searches were systematically conducted in the PubMed and Embase databases. RESULTS: Literature is reported on device management in the following settings: general operating room recommendations, electrocautery, ultrasound and other forms of diathermy, implanted cardiac devices, defibrillation, and magnetic resonance imaging. DISCUSSION: SNM devices have shown efficacy in treatment for a wide array of conditions. When proper precautions and guidelines are followed, the device can be safely and appropriately integrated in clinical practice. CONCLUSIONS: Available information on management in a variety of periprocedural settings is summarized. However, there are areas that lack satisfactory information, which are highlighted throughout the article.

Wireless Peripheral Nerve Stimulation for Treatment of Peripheral Neuralgias.

BACKGROUND: Peripheral neuralgia is a common cause of chronic pain. Treatment might be challenging, and the condition can be resistant to commonly used treatment modalities for chronic pain. We present five cases of peripheral neuralgia who were successfully treated using wireless peripheral nerve stimulation. MATERIALS AND METHODS: This was a retrospective case series that includes a description of five patients who underwent wireless peripheral nerve stimulator therapy for the treatment of peripheral neuralgia. RESULTS: The patients in this case series underwent peripheral nerve stimulator placement for the treatment of superior cluneal, sural, ilioinguinal and genitofemoral neuralgias. Patients reported a decline in their Numerical Rating Scale (NRS) pain scores from a mean of 6.4 before the procedure to a score of 1 following implant. The change in pain scores was found to be statistically significant (p < 0.05). CONCLUSIONS: We present five patients with peripheral neuralgias resistant to other treatment modalities who received excellent pain relief following implantation of a peripheral nerve stimulator.

Injection Techniques for Common Chronic Pain Conditions of the Foot: A Comprehensive Review.

PURPOSE OF REVIEW: This is a comprehensive literature review of the available evidence and techniques of foot injections for chronic pain conditions. It briefly describes common foot chronic pain syndromes and then reviews available injection techniques for each of these syndromes, weighing the available evidence and comparing the available approaches. RECENT FINDINGS: Foot and ankle pain affects 20% of the population over 50 and significantly impairs mobility and ability to participate in activities of daily living (ADLs), as well as increases fall risk. It is commonly treated with costly surgery, at times with questionable efficacy. Injection therapy is challenging when the etiology is anatomical or compressive. Morton's neuroma is a budging of the interdigital nerve. Steroid, alcohol, and capsaicin injections provide some benefit, but it is short lived. Hyaluronic acid (HA) injection provided long-term relief and could prove to be a viable treatment option. Achilles tendinopathy (AT) is most likely secondary to repeat tendon stress-platelet-rich-plasma (PRP) and prolotherapy have been trialed for this condition, but more evidence is required to show efficacy. Similar injections were trials for plantar fasciitis and achieved only short-term relief; however, some evidence suggests that PRP injections reduce the frequency of required therapy. Tarsal tunnel syndrome, a compressive neuropathy carries a risk of permanent neural injury if left untreated. Injection therapy can provide a bridge to surgery; however, surgical decompression remains the definitive therapy. When the etiology is inflammatory, steroid injection is more likely to provide benefit. This has been shown in several studies for gout, as well as osteoarthritis of the foot and ankle and treatment-refractory rheumatoid arthritis. HA showed similar benefit, possibly due to anti-inflammatory effects. Stem cell injections may provide the additional benefit of structure restoration. Chronic foot pain is common in the general population and has significant associated morbidity and disability. Traditionally treated with surgery, these are costly and only somewhat effective. Injections provide an effective alternative financially and some evidence exists that they are effective in pain alleviation. However, current evidence is limited and the benefit described from injection therapy has been short-lived in most cases. Further studies in larger populations are required to evaluate the long-term effects of these treatments.

Periprocedural Considerations for Patients with Gastric Electrical Stimulators.

OBJECTIVES: Gastric electrical stimulation (GES) is a technology that uses neurostimulation for the modulation of gastric activity. In clinical practice, the most commonly encountered form of GES is high frequency GES. GES devices are typically used for the treatment of refractory gastroparesis, although they have also been investigated for obesity management and the treatment of refractory gastroesophageal reflux disease. Just as many patients with chronic diseases require surgery, patients with an implanted GES device may encounter the need for periprocedural care. Therefore, the purpose of this review is to address the special needs of patients with an implanted GES device. MATERIALS AND METHODS: A systematic computerized search of the literature was performed to consolidate existing knowledge on GES management in the periprocedural setting. Duplicate results were eliminated, and results were further narrowed based on title and abstract. All articles with possible relevance were then reviewed in full. Manufacturer information including pamphlets and websites were also reviewed. RESULTS: A total of 1201 articles were identified for initial review, and 33 met inclusion criteria. CONCLUSIONS: Available data suggests GES is a technology with increasing prevalence. When patients with an implanted GES device present for periprocedural care, the anesthesia staff must consider the device when planning for the procedure. Topics addressed include general anesthetic considerations, nerve localization, radiation exposure, electrocautery, diathermy, emergency external defibrillation, and MRI compatibility.