OBJECTIVE:Chronic pain patients experience more work disability leading to unemployment and major individual, societal and economic burden. Implanted neurostimulation has proven good results in terms of pain relief for chronic pain patients. As new stimulation techniques, paradigms and targets are being researched, a comprehensive synthesis of the effects of implanted neurostimulation on occupational outcomes remains undetermined. METHODS:MEDLINE (via PubMed), Embase, Scopus & Web of Science were systematically searched. Risk-of-bias was assessed using the modified Downs & Black checklist. Random-effects meta-analyses, including a Bayesian approach, were conducted to provide estimates of work status and return to work rates. The study protocol was prospectively registered on PROSPERO (CRD42024501152). RESULTS:67 studies were identified for inclusion in the review; 56 were included in the meta-analysis. The paired odds to work following neurostimulator implantation increased significantly (OR 5.17; 95%CI 2.89-9.23; I2=49.0%; n = 56; P < 0.0001) and were confirmed in the conservative random-effects (OR 3.39; 95%CI 2.00-5.75; n = 56; P < 0.0001) and Bayesian model with uniform prior (OR 5.68; 95%CI 3.08-11.79; n = 56). The pooled estimate for the proportion of patients returning to work across neurostimulation modalities was 26.05% (95%CI 20.73%-32.18%; I2=68.9%; n = 55). CONCLUSIONS:Implanted electrical neurostimulation is associated with increased paired odds to work and enabled chronic pain patients to return to work. The best effects were achieved following peripheral nerve stimulation and in patients suffering head-related pain.

Objectives.Chronic pain affects over two billion people worldwide, significantly reducing quality of life and placing a substantial burden on healthcare systems and society. Neuropathic painoriginates from lesions of the central or peripheral nervous system. Despite pharmacological, surgical and paramedical management, many patients continue experiencing persistent pain. Epidural Spinal Cord Stimulation (SCS) has become an effective alternative treatment for neuropathic pain. That said, SCS efficacy is dependent on many parameters, including optimized spatial targeting based on paresthesia generated by chosen and tuned SCS. In this context, iterative programming designed to optimize targeting and pain relief puts a major burden on health-care professionals. The leveraging of FEM and other computational techniques would enhance understanding of SCS mechanisms, optimize parameter selection, and ultimately improve patient outcomes.Approach. In this work, we present parametrizable computational model that facilitates the study of computed paresthesia. This model used the typical workflow of two-step simulation often employed for electrical stimulation of neural structures. First, the electrical field generated within the spinal cord and its surroundings was computed using the Finite-Element Method (FEM). The effects this electric field had on axons were then assessed with Ordinary Differential Equations (ODEs). The geometry of this model was based on a section of the PAM50 template of the spinal cord and its surroundings. Somatotopy of the spinal cord is explicitly represented by the fiber's trajectories. Aβmyelinated fibers of the dorsal columns and roots are modelled using the McIntyre-Richardson-Grill (MRG) double cable model.Main results.The computational model produced paresthesia maps which generally followed expected projections in terms of lead laterality and rostro-caudal placement in paresthesia. Some interesting effects of rostro-caudal lead placement ata vertebral level were also observed and will be discussed.Significance. The computed paresthesia maps, which can be directly correlated to felt or measured paresthesia maps, represent a step towards clinical validation of in silico computational models of SCS.

Introduction The dorsal root ganglion (DRG) is an important target for treating chronic refractory pain. However, determining the optimal electrode location for DRG stimulation remains challenging. Conventionally, the ganglion is targeted within the infrapedicular zone of the neuro-foramen for DRG stimulation using radiological imaging. However, clinical experience suggests that optimal focal pain paresthesia stimulation coverage (PPC) often occurs at sites other than directly over the ganglion, indicating that periganglionic neural structures also may play a role as therapeutic targets. Materials and Methods Electro-stimulation mapping (ESM) was performed in seven subjects who had previously been implanted with transforaminal spinal cord stimulation (SCS) leads for focal neuropathic lower trunk and limb pain; 12 octapolar transforaminal SCS leads, programmed for monopolar stimulation across multiple lumbar spine levels, were evaluated. At each electrode, stimulation amplitudes were assessed for sensory perception, optimal comfortable stimulation, and uncomfortable stimulation. Using standard radiologic techniques, 288 paresthesia mappings were anatomically related to the spinal pedicles, and categorized into intraspinal, foraminal, and extraforaminal zones to determine optimal pain-paresthesia coverage (PPC) electrode proximity to the putative DRG location. Results Optimal focal PPC performance occurred within the conventional radiographic ganglion region in only 25% of electrodes, whereas 75% of electrodes having optimal PPC performance were located outside the defined foraminal zone. ESM also delineated the physiologic and biophysical boundaries of the neuro-foramen that were not reliably identifiable on the anteroposterior projection alone. Conclusions Optimal PPC is not consistently achieved by stimulating directly within the presumed DRG zone and may engage different mechanisms of action across the DRG and adjacent neural structures. Our findings highlight the importance of precise electrode localization, support further comparison of PPC-based targeting with on-label DRG stimulation therapy, and justify the broader term spinal transforaminal stimulation to describe stimulation delivered to these neural targets.

Introduction The field of spinal cord stimulation (SCS) is characterized by the availability of multiple stimulation paradigms and device options, yet limited evidence exists on ways health care providers make decisions during clinical reasoning. This study aimed to explore health care providers’ opinions and reasoning during the decision-making process in SCS therapy, focusing on factors influencing the choice of stimulation paradigm and manufacturer. Materials and Methods An online survey was distributed among health care professionals involved in neuromodulation for pain through the North American Neuromodulation Society newsletter and during the 2nd Pain Academy in Madrid (2024). Health care professionals were asked to indicate the reasoning behind the decision-making on which type of SCS will be implanted, and from which manufacturer devices will be implanted. Results A total of 102 respondents completed the survey, of whom 90 were clinical practitioners or nurses and included in the analysis. The first major decision typically concerned the selection of the stimulation paradigm (39.8%), primarily influenced by patient pathology and characteristics. The choice of manufacturer was primarily determined by the level of technical support and service. Paresthesia-based SCS remained widely used (64.6%), yet paresthesia-free stimulation was more often used (86.6%). Magnetic resonance imaging (MRI) conditionality and other extraparadigm features also were identified as relevant determinants in device selection. Discussion Decision-making in SCS shows substantial variability among health care providers. Although implanters generally hold final responsibility, factors such as patient characteristics, manufacturer support, and MRI conditionality play a major role in guiding clinical choices. These findings underscore the need for clearer decision frameworks, transparent reasoning, and greater multidisciplinary involvement in SCS therapy selection.

BACKGROUND:Poststroke flexed elbow deformity is a frequent and disabling abnormal joint posture that impairs function, hygiene, and quality of life. Despite its clinical impact, assessment strategies and treatment sequencing remain heterogeneous, fragmented across disciplines, and poorly standardized. OBJECTIVES:To establish an international, interdisciplinary expert consensus on the assessment and management of poststroke flexed elbow deformity using a hypothesis-driven Delphi methodology. METHODS:An international Delphi process was conducted involving 28 experts in physical and rehabilitation medicine, orthopedic surgery, and neurosurgery from 12 countries. Three sequential, anonymous rounds of structured online questionnaires were administered. Statements addressed diagnosis, clinical and instrumental assessment, treatment selection, and surgical indications. Experts rated their agreement with each statement. Consensus was predefined as ≥80% agreement among respondents for a given item. RESULTS:Across 3 Delphi rounds, 164 statements were evaluated, of which 61 (38%) reached consensus. Experts, including physical and rehabilitation medicine physicians (n = 13), orthopedic surgeons (n = 10), and neurosurgeons (n = 1) agreed that functional impact assessment must precede treatment decisions and that differentiation between muscle overactivity and soft-tissue contracture is essential. Diagnostic motor nerve blocks and radiological imaging were endorsed as complementary tools in selected cases. Botulinum toxin injections combined with rehabilitation were supported as first-line treatment for correctable deformities, whereas surgical intervention was considered appropriate for partially or non-correctable deformities. Preoperative interdisciplinary consultation and formal goal setting were deemed mandatory before intervention. CONCLUSIONS:This Delphi-based international consensus provides structured, interdisciplinary guidance for the evaluation and management of poststroke flexed elbow deformity. By clarifying assessment principles, treatment sequencing, and indications for referral and surgery, this consensus aims to standardize care pathways and improve patient-centered outcomes. REGISTRATION:Not applicable. This study used a Delphi methodology involving expert opinion only, without human participant intervention.

La stimulation nerveuse périphérique implantée (SNPI) est une technique de neuromodulation qui consiste à implanter des électrodes délivrant des impulsions électriques ciblées sur un nerf périphérique afin de réduire la douleur. Introduite en 1965, elle a connu une trajectoire en quatre temps : des débuts chirurgicaux lourds, une phase d’optimisation technologique dans les années 1970–1980 vite freinée par les complications et l’essor concurrent de la stimulation médullaire, un renouveau avec l’apparition des électrodes percutanées élargissant les indications, puis l’ère moderne où l’échographie et les dispositifs miniaturisés permettent une approche précise, sûre et mini-invasive. Ses mécanismes d’action dépassent la théorie du « gate control » et combinent des effets périphériques, spinaux et centraux. La stimulation réduit l’excitabilité des fibres nociceptives et module localement les médiateurs biochimiques. Au niveau spinal, elle inhibe les voies ascendantes nociceptives et stimule les circuits inhibiteurs descendants. Elle agit enfin sur des structures cérébrales impliquées dans la perception et la modulation de la douleur, comme le cortex préfrontal, le cingulaire antérieur ou la substance grise périaqueducale. La stimulation du nerf occipital illustre particulièrement bien cette synergie multi-niveaux et a permis de valider la technique dans certaines céphalées chroniques. Initialement réservée aux neuropathies focalisées rebelles et aux douleurs crânio-faciales, la SNPI s’étend aujourd’hui aux douleurs chroniques des membres, aux lombalgies, aux douleurs post-amputation et à certains contextes périopératoires. Elle ne se limite plus à un rôle antalgique : en ciblant des nerfs moteurs comme les rameaux médiaux lombaires, elle contribue aussi à la réhabilitation fonctionnelle, notamment par l’activation du muscle multifidus dans la lombalgie chronique ou par la récupération motrice de l’épaule après hémiplégie. Son essor reste freiné par l’inégalité d’accès au matériel, l’absence de remboursement et la nécessité d’une expertise pointue en échoguidage et en sélection des patients. L’avenir dépendra de la standardisation des pratiques, du développement d’équipes formées et de la reconnaissance médico-économique. Si ces défis sont relevés, la SNPI pourrait devenir un pilier de la médecine interventionnelle de la douleur et de la réhabilitation.

Differential target multiplexed spinal cord stimulation (DTM SCS) is a stimulation paradigm for chronic pain management that aims to modulate neuron-glial interactions. In parallel, closed-loop SCS systems using evoked compound action potential (ECAP) sensing have been introduced to adjust stimulation output in response to measured neural activation. Although clinical evidence for DTM SCS has expanded, data remain limited for patients with Persistent Spinal Pain Syndrome Type 2 (PSPS-T2), particularly regarding ECAP-controlled closed-loop DTM SCS and its implementation in routine European practice. ENDLESS aims to investigate the feasibility, safety, and longitudinal clinical outcomes associated with open-loop and closed-loop DTM SCS in patients with PSPS-T2 through a longitudinal European multicentre cohort study. ENDLESS is a prospective multicentre cohort study including at least 200 patients, with follow-up until 12 months after implantable pulse generator activation. Outcomes will be assessed at baseline and at 1, 6 and 12 months after DTM SCS initiation. The primary effectiveness endpoint is pain intensity, measured using the Visual Analogue Scale through ecological momentary assessment. Secondary effectiveness outcomes include pain intensity with and without medication use, negative affect, disability, health-related quality of life, pain medication use, clinical holistic responder status, patient impression of change, work status, pain catastrophising, symptoms of anxiety and depression, patient unwanted stimulation awareness and patient expectations. In a subset of patients, sleep, activity patterns and RR-intervals will be assessed using actigraphy. Device-derived outcomes will include time spent in different body postures, technical implantable pulse generator details, battery consumption, stimulation parameters, programming information and ECAP-related data when closed-loop DTM SCS is used. Technical issues, adverse events, serious adverse events and the proportion of successful DTM SCS trial periods will also be documented. Longitudinal mixed models will be used to evaluate changes in effectiveness outcomes over time.Trial registration numberClinicalTrials.gov identifier NCT07211308.

INTRODUCTION:During the last century, many ethics codes have emerged, sometimes embedding legally binding instruments, sometimes encoding good clinical practice for the first time. Apart from the general ethical considerations in use of neuromodulation devices, regulators have tried to shield the patient, implanters, and society from possible risks related to such devices, namely, the protection of the patient's privacy and ensuring enduring manufacturer responsibility for the lifecycle of the device. This review aims to reveal the limits of ethics guidelines, the personal responsibility of the researcher, and the usefulness of the European legal, in addition to the international, ethics and deontology frameworks for clinical investigations in neuromodulation. It also introduces a practical tool, the Chimaera Contemplation Checklist, to support researchers throughout the clinical research cycle. MATERIALS AND METHODS:In this narrative review, the full research cycle for clinical investigations with neuromodulation devices is discussed. Practical advice building on multidisciplinary experience in clinical neuromodulation practice, involving social researchers and legal and ethics advisors, is provided. The review integrates the Chimaera Contemplation Checklist as a structured aid for ethical and legal reflection. RESULTS:The article focuses on common hurdles, namely, patient-centered study designs, obtaining true informed consent, clear contracts between sponsors and research partners, posttrial accessibility and support of the device, usefulness of standards, and expectations with respect to institutional review boards. The Chimaera Contemplation Checklist summarizes these challenges and offers practical prompts for researchers at each stage. DISCUSSION:This review highlights that general ethical guidelines and legislation do not easily translate to the practical needs of neuromodulation research. Addressing this gap is essential to support robust, ethical, and legally compliant research that prioritizes patient well-being. With the growing number of regulations concerning medical devices, raising awareness and fostering a deeper understanding of these guidelines is crucial. Collaboration among experts from diverse fields, including law, information technology, research, medical ethics committees, and policy, will play a key role in shaping the future of clinical trials in neuromodulation. The Chimaera Contemplation Checklist serves as a concrete, multidisciplinary tool to guide this process.