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Introduction: The International Neuromodulation Society convened a multispecialty group of physicians and scientists based on expertise with international representation to establish evidence-based guidance on intrathecal drug delivery in treating chronic pain. This Polyanalgesic Consensus Conference (PACC)® project, created more than two decades ago, intends to provide evidence-based guidance for important safety and efficacy issues surrounding intrathecal drug delivery and its impact on the practice of neuromodulation., Materials and Methods: Authors were chosen on the basis of 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 PACC® last published guidelines) to the present. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence is scant., Results: The PACC® 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 PACC® recommends best practices regarding intrathecal drug delivery to improve safety and efficacy. The evidence- and consensus-based recommendations should be used as a guide to assist decision-making when clinically appropriate., Competing Interests: Conflict of Interest Alaa Abd-Elsayed is a consultant for Medtronic. Philip Kim reports consulting fees from Medtronic, personal fees from TerSera, outside the submitted work; personal fees from Biotronik and Medtronic on a medical board; reseach support from Biotronik, Medtronic, Boston, Nevro, Saluda, and Cornerloc; and participation in a data safety monitoring board on RTX on Morton neuroma study. Christophe Perruchoud reports consulting fees, honoraria, and participation on a data safety monitoring board or advisory board for Medtronic. Anjum Bux reports personal fees from Flowonix Corp, Boston Scientific, AIS, Medtronic, and Vertos, outside the submitted work. Rui Duarte reports personal fees from Saluda Medical, Boston Scientific, Medtronic, and Mainstay Medical, outside the submitted work. Michael Saulino reports research grants from Medtronic and Flowonix; fellowship support from Medtronic, Piramal, and Saol; Denis Dupoiron reports personal fees from Medtronic and Esteve, outside the submitted work. Dennis Patin consults for Medtronic, Abbott, Boston Scientific, and Nevro. Julie G. Pilitsis reports grants and other from Boston Scientific, Nevro, Abbott, TerSera, and Medtronic; other from Saluda, Aim Medical Robotics, and Karuna Labs; grants from National Institutes of Health (NIH) 2R01CA166379-06; and grants from NIH U44NS115111, outside the submitted work. Lawrence R. Poree reports personal fees from Medtronic and Nalu, and grants and personal fees from Saluda, outside the submitted work. Harry Sukumaran reports personal fees from Abbott, Boston Scientific, and Nevro, and personal fees and nonfinancial support from Vertos Medical, outside the submitted work. Erik Shaw reports support from Pfizer/Lilly for tanezumab articles; consulting fees and/or honoraria from TerSera, Boston Scientific, SPR Therapeutics; participation on a data safety monitoring board or advisory board for Pfizer/Lilly NGF blocker; and stock options from SpineThera and ROM Tech. Tony L. Yaksh reports grants from NIH-National Institute of Neurological Disorders and Stroke (NINDS), other from CODA, IONIS, and Medtronic during the conduct of the study; grants from NIH-NINDS, IONIS, and Medtronic, outside the submitted work. Robert M. Levy is an unpaid and uncompensated consultant for Abbott, Biotronik, Nalu, and Synergia. The remaining authors reported no conflict of interest., (Copyright © 2024. Published by Elsevier Inc.)

Background: Current guidelines recommend a personalized, multimodal, and interdisciplinary approach for the treatment of chronic pain. Already in the acute treatment of postoperative pain, it can be useful to minimize risk factors for chronification. Auricular vagus nerve stimulation (aVNS) could be an effective non-drug therapy for the treatment of chronic and acute pain., Aim of the Work: The aim of this systematic review is to evaluate the clinical efficacy of aVNS in chronic and acute pain as well as its effect on medication intake., Materials and Methods: A systematic literature search was carried out on the application of auricular electrical stimulation in chronic and acute pain. Studies were classified according to their level of evidence and evaluated via the Jadad scale as well as their scientific validity, and then analyzed in terms of indication, method, stimulation parameters, duration of treatment, efficacy, and safety., Results: Twenty studies on chronic pain indications, ten studies on acute postoperative pain, as well as seven studies on experimental acute pain were identified and analyzed. The search revealed a total of n = 1105 aVNS-treated patients. The best evidence on the efficacy of aVNS is available for the indications chronic low back pain, chronic cervical syndrome, chronic abdominal pain, and chronic migraine as well as acute postoperative pain in oocyte aspiration, laparoscopic nephrectomy, and open colorectal surgery. Additionally a significant reduction in analgesic or opiate intake was evident in most studies. In three randomized controlled trials in chronic pain patients, a sustainable pain reduction over a period of up to 12 months was shown. Overall, aVNS was very well tolerated., Conclusion: This review indicates that aVNS can be a complementary and effective non-drug treatment for patients with chronic and acute postoperative pain. Future studies in these indications should focus on standardizing and optimizing treatment parameters, inclusion of quality-of-life outcome parameters, and longer follow-up periods to better understand the sustainable therapeutic effect of aVNS., (© 2023. The Author(s).)

Intrathecal drug delivery appeared in the early eighties and allows to administer high concentrate analgesic medications in the cerebrospinal fluid with higher efficacy and a limited incidence of systemic side effects. Opioids are still the first line treatment with high-quality evidence for chronic cancer pain, and limited evidence for chronic non-cancer pain, being often considered as a last resort therapy. Device implantation requires a strict patient's selection with a close follow-up in order to adapt therapy, refill the reservoir and detect and prevent potential severe complications., Competing Interests: Christophe Perruchoud est consultant pour Medtronic (advisory board). L’autre auteur n’a déclaré aucun conflit d’intérêts en relation avec cet article.

Objective: For many medical professionals dealing with patients with persistent pain following spine surgery, the term Failed back surgery syndrome (FBSS) as a diagnostic label is inadequate, misleading, and potentially troublesome. It misrepresents causation. Alternative terms have been suggested, but none has replaced FBSS. The International Association for the Study of Pain (IASP) published a revised classification of chronic pain, as part of the new International Classification of Diseases (ICD-11), which has been accepted by the World Health Organization (WHO). This includes the term Chronic pain after spinal surgery (CPSS), which is suggested as a replacement for FBSS., Methods: This article provides arguments and rationale for a replacement definition. In order to propose a broadly applicable yet more precise and clinically informative term, an international group of experts was established., Results: 14 candidate replacement terms were considered and ranked. The application of agreed criteria reduced this to a shortlist of four. A preferred option-Persistent spinal pain syndrome-was selected by a structured workshop and Delphi process. We provide rationale for using Persistent spinal pain syndrome and a schema for its incorporation into ICD-11. We propose the adoption of this term would strengthen the new ICD-11 classification., Conclusions: This project is important to those in the fields of pain management, spine surgery, and neuromodulation, as well as patients labeled with FBSS. Through a shift in perspective, it could facilitate the application of the new ICD-11 classification and allow clearer discussion among medical professionals, industry, funding organizations, academia, and the legal profession., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.)

Neuromodulation techniques modify the activity of the central or peripheral nervous system. Spinal cord stimulation is a reversible and minimally invasive treatment whose efficacy and cost effectiveness are recognized for the treatment of chronic neuropathic pain or ischemic pain. Spinal cord stimulation is not the option of last resort and should be considered among other options before prescribing long-term opioids or considering reoperation. The selection and regular follow-up of patients are crucial to the success of the therapy.

Background: Chronic postsurgical pain (CPSP) is an important clinical problem. Prospective studies of the incidence, characteristics and risk factors of CPSP are needed., Objectives: The objective of this study is to evaluate the incidence and risk factors of CPSP., Design: A multicentre, prospective, observational trial., Setting: Twenty-one hospitals in 11 European countries., Patients: Three thousand one hundred and twenty patients undergoing surgery and enrolled in the European registry PAIN OUT., Main Outcome Measures: Pain-related outcome was evaluated on the first postoperative day (D1) using a standardised pain outcome questionnaire. Review at 6 and 12 months via e-mail or telephonic interview used the Brief Pain Inventory (BPI) and the DN4 (Douleur Neuropathique four questions). Primary endpoint was the incidence of moderate to severe CPSP (numeric rating scale, NRS ≥3/10) at 12 months., Results: For 1044 and 889 patients, complete data were available at 6 and 12 months. At 12 months, the incidence of moderate to severe CPSP was 11.8% (95% CI 9.7 to 13.9) and of severe pain (NRS ≥6) 2.2% (95% CI 1.2 to 3.3). Signs of neuropathic pain were recorded in 35.4% (95% CI 23.9 to 48.3) and 57.1% (95% CI 30.7 to 83.4) of patients with moderate and severe CPSP, respectively. Functional impairment (BPI) at 6 and 12 months increased with the severity of CPSP (P < 0.01) and presence of neuropathic characteristics (P < 0.001). Multivariate analysis identified orthopaedic surgery, preoperative chronic pain and percentage of time in severe pain on D1 as risk factors. A 10% increase in percentage of time in severe pain was associated with a 30% increase of CPSP incidence at 12 months., Conclusion: The collection of data on CPSP was feasible within the European registry PAIN OUT. The incidence of moderate to severe CPSP at 12 months was 11.8%. Functional impairment was associated with CPSP severity and neuropathic characteristics. Risk factors for CPSP in the present study were chronic preoperative pain, orthopaedic surgery and percentage of time in severe pain on D1., Trial Registration: Clinicaltrials.gov identifier: NCT01467102.

Objectives: To define the key terms and concepts relating physical activity to chronic pain; to provide a brief overview of the various methods of assessment of physical activity; to review the current literature about physical activity and chronic pain; and to identify needs for future research., Materials and Methods: A narrative review based on results of a PubMed search (to May 2011) and the references of recent systematic reviews., Results: Many methods exist for measuring physical activity. Movement sensors, such as accelerometers, offer objective assessment of physical activity of patients with chronic pain. It is often assumed that patients who feel disabled and report daily life restrictions due to chronic pain also will be less physically active. Studies that have compared the activity of patients with chronic back pain with that of healthy individuals consistently showed that the relationship of physical activity and severity of pain, as well as the change in activity following interventions, was variable and complex., Conclusions: It is important to understand the relationship between physical activity and chronic pain. Future studies should objectively assess not only the pattern and complexity of that relationship but also the interaction with the patient's mood and ability to cope with the pain., (© 2014 International Neuromodulation Society.)

Objectives: This study evaluated efficacy and safety of bolus doses of ziconotide (Prialt®, Eisai Limited, Hertfordshire, UK) to assess the option of continuous administration of this drug via an implanted intrathecal drug delivery system., Materials and Methods: Twenty adults with severe chronic pain who were under consideration for intrathecal (IT) therapy were enrolled in this open label, nonrandomized, pilot study. Informed consent was obtained. Demographics, medical/pain history, pain scores, and concomitant medications were recorded. A physical examination was performed. Creatine kinase was measured. Initial visual analog scale (VAS), blood pressure, heart rate, and respiratory rate were recorded. All patients received an initial bolus dose of 2.5 mcg ziconotide; the dose in the subsequent visits was modified according to response. Subsequent doses were 2.5 mcg, 1.2 mcg, or 3.75 mcg as per protocol. A good response (≥30% reduction in baseline pain VAS) with no side-effects on two occasions was considered a successful trial. Data were analyzed using a generalized estimating equations model, with pain VAS as the outcome and time (seven time points; preinjection and one to six hours postinjection) as the predictor., Results: Generalized estimating equations analysis of summary measures showed a mean reduction of pain VAS of approximately 25% at the group level; of 11 responders, seven underwent pump implantation procedure, two withdrew because of adverse effects, one refused an implant, and one could not have an implant (lack of funding from the Primary Care Trust)., Conclusions: Our data demonstrated that mean VAS was reduced by approximately 25% at the group level after IT ziconotide bolus. Treatment efficacy did not vary with sex, center, age, or pain etiology. Ziconotide bolus was generally well tolerated. Larger studies are needed to determine if bolus dosing with ziconotide is a good predictor of response to continuous IT ziconotide via an intrathecal drug delivery system., (© 2012 International Neuromodulation Society.)

Introduction: Spinal cord stimulation is a recognized treatment of chronic neuropathic and vascular pain. Recent data suggest that the use of very high-frequency (HF) stimulation modes does produce analgesia without paresthesia., Aim of the Study: To compare the efficacy of HF stimulation (HF spinal cord stimulation [HFSCS]) and sham stimulation on the patient's global impression of change (PGIC), pain intensity, and quality of life., Patients and Methods: Forty patients who have achieved stable pain relief with conventional SCS have been recruited. After randomization, HFSCS and sham are initiated in a double-blind randomized two-period-crossover design., Results: Complete data were available from 33 patients. The primary outcome was a minimal improvement in the PGIC. The proportion of patients responding under HFSCS was 42.4% (14/33 patients) vs. 30.3% (10/33 patients) in the sham condition. The mean benefit of HF vs. sham was not statistically significant with a proportion of 11.2% in favor of HFSCS (p = 0.30). There was a highly statistically significant "period effect," irrespective of treatment received, with 51.5% of patients (N = 17) improving at visit 3 vs. 21.2% (N = 7) at visit 5 (p = 0.006). The mean pain visual analog scale (VAS) on sham was 4.26 vs. 4.35 on HFSCS (p = 0.82) and the mean EuroQol five-dimensional (EQ-5D) index with HFSCS was 0.480 vs. 0.463 with sham (p = 0.78)., Conclusion: This is the first randomized double-blind study on SCS. HFSCS was equivalent to sham for the primary outcome (improvement of PGIC) as well as for both the secondary outcomes (VAS and EQ-5D index). There was a highly statistically significant "period effect" (p = 0.006) with improved PGIC scores in the first study period regardless of the treatment. The same trend was seen for VAS and EQ-5D. It appears that the effect of HFSCS and sham is equal and only the order in the sequence, not the nature of the treatment, seems to dictate the effect., (© 2013 International Neuromodulation Society.)

Background: Modern theories define chronic pain as a multidimensional experience - the result of complex interplay between physiological and psychological factors with significant impact on patients' physical, emotional and social functioning. The development of reliable assessment tools capable of capturing the multidimensional impact of chronic pain has challenged the medical community for decades. A number of validated tools are currently used in clinical practice however they all rely on self-reporting and are therefore inherently subjective. In this study we show that a comprehensive analysis of physical activity (PA) under real life conditions may capture behavioral aspects that may reflect physical and emotional functioning., Methodology: PA was monitored during five consecutive days in 60 chronic pain patients and 15 pain-free healthy subjects. To analyze the various aspects of pain-related activity behaviors we defined the concept of PA 'barcoding'. The main idea was to combine different features of PA (type, intensity, duration) to define various PA states. The temporal sequence of different states was visualized as a 'barcode' which indicated that significant information about daily activity can be contained in the amount and variety of PA states, and in the temporal structure of sequence. This information was quantified using complementary measures such as structural complexity metrics (information and sample entropy, Lempel-Ziv complexity), time spent in PA states, and two composite scores, which integrate all measures. The reliability of these measures to characterize chronic pain conditions was assessed by comparing groups of subjects with clinically different pain intensity., Conclusion: The defined measures of PA showed good discriminative features. The results suggest that significant information about pain-related functional limitations is captured by the structural complexity of PA barcodes, which decreases when the intensity of pain increases. We conclude that a comprehensive analysis of daily-life PA can provide an objective appraisal of the intensity of pain.