The Polyanalgesic Consensus Conference (PACC)®: Intrathecal Drug Delivery Guidance on Safety and Therapy Optimization When Treating Chronic Noncancer Pain.

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.

The Neurostimulation Appropriateness Consensus Committee (NACC)®: Recommendations for the Mitigation of Complications of Neurostimulation.

INTRODUCTION: The International Neuromodulation Society convened a multispecialty group of physicians based on expertise and international representation to establish evidence-based guidance on the mitigation of neuromodulation complications. This Neurostimulation Appropriateness Consensus Committee (NACC)® project intends to update evidence-based guidance and offer expert opinion that will improve efficacy and safety. 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 NACC last published guidelines) to October 2023. 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 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 mitigation of complications associated with neurostimulation to improve safety and efficacy. The evidence- and consensus-based recommendations should be used as a guide to assist decision-making when clinically appropriate.

The Neurostimulation Appropriateness Consensus Committee (NACC)®: Recommendations for Spinal Cord Stimulation Long-term Outcome Optimization and Salvage Therapy.

INTRODUCTION: The International Neuromodulation Society (INS) has recognized a need to establish best practices for optimizing implantable devices and salvage when ideal outcomes are not realized. This group has established the Neurostimulation Appropriateness Consensus Committee (NACC)® to offer guidance on matters needed for both our members and the broader community of those affected by neuromodulation devices. MATERIALS AND METHODS: The executive committee of the INS nominated faculty for this NACC® publication on the basis of expertise, publications, and career work on the issue. In addition, the faculty was chosen in consideration of diversity and inclusion of different career paths and demographic categories. Once chosen, the faculty was asked to grade current evidence and along with expert opinion create consensus recommendations to address the lapses in information on this topic. RESULTS: The NACC® group established informative and authoritative recommendations on the salvage and optimization of care for those with indwelling devices. The recommendations are based on evidence and expert opinion and will be expected to evolve as new data are generated for each topic. CONCLUSIONS: NACC® guidance should be considered for any patient with less-than-optimal outcomes with a stimulation device implanted for treating chronic pain. Consideration should be given to these consensus points to salvage a potentially failed device before explant.

The MOTION study: Two-year results of a real-world randomized controlled trial of the mild® procedure for treatment of lumbar spinal stenosis.

OBJECTIVE: The MOTION study is designed to measure the impact of percutaneous image-guided lumbar decompression as a first-line therapy on patients otherwise receiving real-world conventional medical management for lumbar spinal stenosis with neurogenic claudication secondary to hypertrophic ligamentum flavum. This prospective, multicenter randomized controlled trial uses objective and patient-reported outcome measures to compare the combination of the mild® percutaneous treatment and nonsurgical conventional medical management (CMM) to CMM-Alone. METHODS: Test group patients received the mild procedure after study enrollment. Test and control groups were allowed conventional conservative therapies and low-risk interventional therapies as recommended by their physicians. Subjective outcomes included the Oswestry Disability Index, Numeric Pain Rating Scale, and Zurich Claudication Questionnaire. Objective outcomes included a validated Walking Tolerance Test, the rate of subsequent lumbar spine interventions, and safety data. RESULTS: Two-year follow-up included 64 mild + CMM and 67 CMM-Alone patients. All outcome measures showed significant improvement from baseline for mild + CMM, whereas the majority of CMM-Alone patients had elected to receive mild treatment or other lumbar spine interventions by 2 years, precluding valid 2-year between-group comparisons. Neither group reported any device- or procedure-related adverse events. CONCLUSIONS: The durability of mild + CMM for this patient population was demonstrated for all efficacy outcomes through 2 years. Improvements in walking time from baseline to 2 years for patients treated with mild + CMM were significant and substantial. The lack of reported device or procedure-related adverse events reinforces the strong safety profile of the mild procedure. These results provide support for early interventional treatment of symptomatic LSS with the mild procedure.

Relationship between number of prior lumbar spine surgeries and outcomes following spinal cord stimulator implantation: A multisite, retrospective pooled analysis.

OBJECTIVES: Lumbar spine surgery is a common procedure for treating disabling spine-related pain. In recent decades, both the number and cost of spine surgeries have increased despite technological advances and modification in surgical technique. For those patients that have continued uncontrolled back and/or lower extremity pain following lumbar spine surgery, spinal cord stimulation (SCS) has emerged as a viable treatment option. However, the impact of lumbar spine surgical history remains largely unstudied. Specifically, the current study considers the impact of number of prior lumbar spine surgeries on pain relief outcomes following SCS implantation. MATERIALS AND METHODS: We queried the electronic medical record of five separate pain practices for all patients who have undergone a SCS implant between January 1, 2017, and March 1, 2020. Inclusion criteria consisted of any patients with an SCS implant who underwent a prior lumbar spine surgery. The primary outcome was the mean calculated percentage pain relief in patients based on number of prior lumbar spine surgeries. RESULTS: There was a total of 1974 total SCS implant cases identified across five separate pain clinics. There was no difference in mean calculated pain relief in patients with one prior spine surgery versus those with two or more prior spine surgeries (28.2% vs. 25.8%, adjusted ß-coefficient -3.1, 95% CI -8.9 to 2.7, p = 0.290). Similarly, when analyzing number of spine surgeries as a continuous variable, there was no association between number of spine surgeries and calculated pain relief (adjusted ß-coefficient -1.5, 95% CI -4.0 to 1.1, p = 0.257). Additionally, after patients were stratified based on waveform, there was no association between number of prior lumbar spine surgeries (analyzed both as a categorical and continuous variable) and calculated percentage pain relief. CONCLUSIONS: This multicentered retrospective study found that there was no significant difference in pain scores in individuals who received SCS following one or more lumbar spine surgeries. Additionally, the waveform of the SCS device had no statistically significant impact on post-operative pain scores following one or more lumbar spine surgeries.

Clinical Longevity of 106,462 Rechargeable and Primary Cell Spinal Cord Stimulators: Real World Study in the Medicare Population.

INTRODUCTION: Spinal cord stimulators (SCS) are available with either primary cell (PC) or rechargeable cell (RC) batteries. Although RC systems are proposed to have a battery longevity upward of nine years, in comparison with four years for PC systems, there are few studies of longevity of SCS in the real world. MATERIALS AND METHODS: This was an observational, nonrandomized, retrospective study of Medicare beneficiaries who received neurostimulator implants in the outpatient hospital. This study used Medicare fee-for-service claims data from 2013 to 2020. The clinical longevity of the implantable pulse generator (IPG), defined as the duration from implant until removal for any reason, was compared between PC and RC devices. Life distribution analysis was used to approximate device lifespan. The secondary analysis separated removals into explant or replacements. The statistics were adjusted for relevant clinical covariates. RESULTS: A total of 25,856 PC and 79,606 RC systems were included in the study. At seven years after implant, 53.8% of PC IPGs and 55.0% of RC IPGs remained in use. The life distribution modeling analysis projected a median lifespan of 8.2 years for PC and 9.0 years for RC devices. The rate of explant was lower for PC devices (19.2%) than for RC devices (22.0%, hazard ratio (HR) = 0.96, p = 0.082), whereas the rate of replacements was higher for PC devices (33.7%) than for RC devices (29.5%, HR = 1.31, p < 0.001). An analysis of the battery type used in device replacements showed an increasing adoption of PC devices over time. CONCLUSIONS: This large, retrospective, real-world analysis of Medicare claims data demonstrated that the clinical longevity of neurostimulator devices is similar for PC and RC batteries. In the past, clinicians may have defaulted to RC devices based on the assumption that they provided extended battery life. Considering this longevity data, clinicians should now consider the choice between PC and RC devices based on other individual factors pertinent to the patient experience and not on purported longevity claims.

Remote Management of Spinal Cord Stimulation Devices for Chronic Pain: Expert Recommendations on Best Practices for Proper Utilization and Future Considerations.

OBJECTIVE: Emerging spinal cord stimulation (SCS) remote monitoring and programming technologies provide a unique opportunity to address challenges of in-person visits and improve patient care, although clinical guidance on implementation is needed. The goal of this document is to establish best clinical practices for integration of remote device management into the care of patients with SCS, including remote monitoring and remote programming. MATERIALS AND METHODS: A panel of experts in SCS met in July 2022, and additional experts contributed to the development of recommendations after the meeting via survey responses and correspondence. RESULTS: Major goals of remote SCS device management were identified, including prompt identification and resolution of SCS-related issues. The panel identified metrics for remote monitoring and classified them into three categories: device-related (eg, stimulation usage); measurable physiologic or disease-related (eg, patient physical activity or pedometry); and patient-reported (eg, sleep quality and pain intensity). Recommendations were made for frequency of reviewing remote monitoring metrics, although providers should tailor follow-up to individual patient needs. Such periodic reviews of remote monitoring metrics would occur separately from automatic monitoring system notifications (if key metrics fall outside an acceptable range). The guidelines were developed in consideration of reimbursement processes, privacy concerns, and the responsibilities of the care team, industry professionals, manufacturers, patients, and caregivers. Both existing and needed clinical evidence were covered, including outcomes of interest for future studies. CONCLUSIONS: Given the expansion of SCS device capabilities, this document provides critical guidance on best practices for using remote device management, although medical necessity should drive all remote monitoring decisions, with individualized patient care. The authors also describe the potential of these emerging technologies to improve outcomes for patients with SCS, although more clinical evidence is needed.

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.

The MOTION Study: A Randomized Controlled Trial with Objective Real-World Outcomes for Lumbar Spinal Stenosis Patients Treated with the mild® Procedure: One-Year Results.

OBJECTIVE: The purpose of this study is to provide Level-1 objective, real-world outcome data for patients with lumbar spinal stenosis suffering from neurogenic claudication secondary to hypertrophic ligamentum flavum. DESIGN: The MOTION Study is a prospective, multicenter, randomized controlled trial comparing the mild® Procedure (minimally invasive lumbar decompression; Vertos Medical, Aliso Viejo, CA, USA) as a first-line therapy in combination with nonsurgical conventional medical management (CMM) vs CMM alone as the active control. METHODS: Patients in the test group received the mild Procedure at baseline. Both the mild+CMM group and the control group were allowed unrestricted access to conventional real-world therapies. Patient-reported outcomes included the Oswestry Disability Index, the Zurich Claudication Questionnaire, and the Numeric Pain Rating Scale. A validated Walking Tolerance Test, the incidence of subsequent lumbar spine interventions, and the occurrence of adverse events were used to measure objective outcomes. RESULTS: Sixty-nine patients in each group were analyzed at 1-year follow-up. No device- or procedure-related adverse events were reported in either group. Results from all primary and secondary outcome measures showed statistical significance in favor of mild+CMM. CONCLUSIONS: One-year results of this Level-1 study demonstrated superiority of mild+CMM over CMM alone for patients with lumbar spinal stenosis who were suffering from neurogenic claudication secondary to hypertrophic ligamentum flavum. Use of the validated Walking Tolerance Test to objectively measure increased ability to walk without severe symptoms provided evidence of statistically significantly better outcomes for mild+CMM than for CMM alone. With no reported device or procedure-related adverse events, the long-standing safety profile of the mild Procedure was reaffirmed. mild is a safe, durable, minimally invasive procedure that has been shown to be effective as an early interventional therapy for patients suffering from symptomatic lumbar spinal stenosis.

An Anatomy-Informed, Novel Technique for S1 Dorsal Root Ganglion Stimulation Lead Placement.

OBJECTIVE: A heightened and organized understanding of sacral anatomy could potentially lead to a more effective and safe method of dorsal root ganglion stimulation (DRG-S) lead placement. The aim of this technical note is to describe a standardized access method for S1 DRG-S lead placement. DESIGN: Technical note. METHODS: The described approach utilizes alignment of the lumbosacral prominence and is measurement-based, allowing for standardized sacral access, even when visualization is suboptimal. The medial-to-lateral needle trajectory is designed to limit interaction with the sensitive neural structures and allows for a more parallel orientation of the lead to the DRG and nerve root. CONCLUSIONS: The described technique potentially improves the safety of S1 DRG-S lead placement. The parallel lead orientation to the DRG may also increase efficacy while lowering energy requirements.

Dorsal Root Ganglion Stimulation for Chronic Groin Pain: A Review.

INTRODUCTION: Chronic neuropathic groin pain develops in a significant number of postsurgical patients; however, multiple etiologies have been identified, and this makes it a challenging condition to treat. While treatment often involves a multimodal approach, advancements in neuromodulation technology, particularly dorsal root ganglion (DRG) stimulation, have benefited patients plagued by chronic pain refractory to standard treatment modalities. Our goal was to provide a definitive source of information for interventional pain physicians regarding groin pain and the use of DRG stimulation for its treatment. MATERIALS AND METHODS: In this narrative review, we provide an overview of groin pain and discuss potential pain generators. We also outline appropriate treatment options with particular interest on DRG stimulation. Lastly, we provide a narrative review of the published literature regarding DRG stimulation for chronic groin pain from a variety of etiologies. CONCLUSION: DRG stimulation has emerged as an alternative neuromodulatory technique for patients with chronic groin pain. While previous studies suggest substantial sustained pain relief with DRG stimulation in this patient population, prospective randomized controlled studies are necessary before formal recommendations can be made.

The Neurostimulation Appropriateness Consensus Committee (NACC): Recommendations for Surgical Technique for Spinal Cord Stimulation.

INTRODUCTION: The field of neurostimulation for the treatment of chronic pain is a rapidly developing area of medicine. Although neurostimulation therapies have advanced significantly as a result of technologic improvements, surgical planning, device placement, and postoperative care are of equal importance to optimize outcomes. This Neurostimulation Appropriateness Consensus Committee (NACC) project intends to provide evidence-based guidance for these often-overlooked areas of neurostimulation practice. MATERIALS AND METHODS: Authors were chosen based on 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 the last NACC publication in 2017 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 evidence strength and consensus when evidence was scant. RESULTS: This NACC project provides guidance on preoperative assessment, intraoperative techniques, and postoperative management in the form of consensus points with supportive evidence. These results are based on grade of evidence, strength of consensus, and expert opinion. CONCLUSIONS: The NACC has given guidance for a surgical plan that encompasses the patient journey from the planning stage through the surgical experience and postoperative care. The overall recommendations are designed to improve efficacy and the safety of patients undergoing these neuromodulation procedures and are intended to apply throughout the international community.

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.

The incidence of lumbar spine surgery following Minimally Invasive Lumbar Decompression and Superion Indirect Decompression System for treatment of lumbar spinal stenosis: a retrospective review.

INTRODUCTION: Lumbar spinal stenosis affects more than 200,000 adults in the United States, resulting in approximately 38,000 operations among the Medicare population and greater than $1.5 billion in hospital bills alone. Fortunately, Minimally Invasive Lumbar Decompression (MILD) and the Superion Indirect Decompression System have shown lasting benefit and cost savings compared to more aggressive surgical options. OBJECTIVE: Our primary objective was to retrospectively determine the rate of lumbar decompression surgery following the MILD and Superion procedures. MATERIALS AND METHODS: This was a pooled retrospective review of LSS patients who received MILD and/or Superion procedures between January 2011 and July 2019. Adult patients with CPT codes for MILD and Superion procedures were identified. Patients were included if they had a follow-up visit at least 2 years from the procedure date, preprocedural MRI results, and surgical notes. RESULTS: A total of 199 patients were included in the final analysis, of which 57 patients (28.6%) underwent MILD procedure only, 124 patients (62.3%) underwent Superion only, and 18 patients (9.0%) underwent an MILD procedure initially followed by a Superion procedure. Two patients had an MILD procedure performed twice at the same level at separate encounters. A total of four patients in the entire cohort (2.0%; MILD 5.3%, Superion 0.8%) underwent subsequent lumbar spine surgery when followed for at least 2 years. It is notable that some of these patients may not have been surgical candidates and this may have skewed the results. CONCLUSIONS: Patients undergoing minimally invasive decompression treatment of lumbar spinal stenosis have low rates of subsequent open surgery which potentially results in cost savings and a reduction in severe adverse events. The reason for low surgical rate may reflect improvement in their symptoms, a preference to avoid surgery, or being deemed not a surgical candidate.

Percutaneous Peripheral Nerve Stimulation of the Medial Branch Nerves for the Treatment of Chronic Axial Back Pain in Patients After Radiofrequency Ablation.

OBJECTIVE: Lumbar radiofrequency ablation is a commonly used intervention for chronic back pain. However, the pain typically returns, and though retreatment may be successful, the procedure involves destruction of the medial branch nerves, which denervates the multifidus. Repeated procedures typically have diminishing returns, which can lead to opioid use, surgery, or implantation of permanent neuromodulation systems. The objective of this report is to demonstrate the potential use of percutaneous peripheral nerve stimulation (PNS) as a minimally invasive, nondestructive, motor-sparing alternative to repeat radiofrequency ablation and more invasive surgical procedures. DESIGN: Prospective, multicenter trial. METHODS: Individuals with a return of chronic axial pain after radiofrequency ablation underwent implantation of percutaneous PNS leads targeting the medial branch nerves. Stimulation was delivered for up to 60 days, after which the leads were removed. Participants were followed up to 5 months after the start of PNS. Outcomes included pain intensity, disability, and pain interference. RESULTS: Highly clinically significant (≥50%) reductions in average pain intensity were reported by a majority of participants (67%, n = 10/15) after 2 months with PNS, and a majority experienced clinically significant improvements in functional outcomes, as measured by disability (87%, n = 13/15) and pain interference (80%, n = 12/15). Five months after PNS, 93% (n = 14/15) reported clinically meaningful improvement in one or more outcome measures, and a majority experienced clinically meaningful improvements in all three outcomes (i.e., pain intensity, disability, and pain interference). CONCLUSIONS: Percutaneous PNS has the potential to shift the pain management paradigm by providing an effective, nondestructive, motor-sparing neuromodulation treatment.

Persistent Spinal Pain Syndrome: A Proposal for Failed Back Surgery Syndrome and ICD-11.

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.

Consensus practice guidelines on interventions for cervical spine (facet) joint pain from a multispecialty international working group.

BACKGROUND: The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial. METHODS: In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4-5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement. RESULTS: Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation. CONCLUSIONS: Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Effect of Patient Characteristics on Clinical Outcomes More Than 12 Months Following Dorsal Root Ganglion Stimulation Implantation: A Retrospective Review.

INTRODUCTION: Dorsal root ganglion (DRG) stimulation is an effective treatment option for lower extremity complex regional pain syndrome and other focal pain conditions. However, the patient characteristics that may predict long-term outcomes have not been defined. MATERIALS AND METHODS: This was a retrospective observational study that included 93 patients who were implanted with a DRG stimulator at a single private practice institution. A variety of demographic data was collected. Follow-up results were reviewed from multiple time points more than 12 months. Patients were classified as either "responder" or "nonresponder" status using two different thresholds, "greater than or equal to 50% pain relief" and "greater than or equal to 80% pain relief." RESULTS: A history of prior chronic opioid use was associated with significantly lower rates of responder status based on both a 50% pain relief threshold and 80% pain relief threshold at the one week to one month, three months, and 12-months visits. CONCLUSIONS: This single-center retrospective study found patients prescribed chronic opioids at the time of DRG stimulator implantation had a higher likelihood of less than 50% pain relief and 80% pain relief at one month, three months, and 12 months follow-up visits.

Novel Intermittent Dosing Burst Paradigm in Spinal Cord Stimulation.

INTRODUCTION: Intermittent dosing (ID), in which periods of stimulation-on are alternated with periods of stimulation-off, is generally employed using 30 sec ON and 90 sec OFF intervals with burst spinal cord stimulation (SCS). The goal of this study was to evaluate the feasibility of using extended stimulation-off periods in patients with chronic intractable pain. MATERIALS AND METHODS: This prospective, multicenter, feasibility trial evaluated the clinical efficacy of the following ID stimulation-off times: 90, 120, 150, and 360 sec with burst waveform parameters. After a successful trial (≥50% pain relief) using ID stimulation, subjects were titrated with OFF times beginning with 360 sec. Pain, quality of life, disability, and pain catastrophizing were evaluated at one, three, and six months after permanent implant. RESULTS: Fifty subjects completed an SCS trial using ID stimulation settings of 30 sec ON and 90 sec OFF, with 38 (76%) receiving ≥50% pain relief. Pain scores were significantly reduced from baseline at all time points (p < 0.001). Improvements in quality of life, disability, and pain catastrophizing were aligned with pain relief outcomes; 45.8% of the subjects that completed the six-month follow-up visit used an OFF period of 360 seconds. CONCLUSIONS: ID burst SCS effectively relieved pain for six months. The largest group of subjects used IDB settings of 30 sec ON and 360 sec OFF. These findings present intriguing implications for the optimal "dose" of electricity in SCS and may offer many advantages such as optimizing the therapeutic window, extending battery life, reducing recharge burden and, potentially, mitigating therapy habituation or tolerance.

Cost-Effectiveness of Dorsal Root Ganglion Stimulation or Spinal Cord Stimulation for Complex Regional Pain Syndrome.

OBJECTIVES: ACCURATE, a randomized controlled trial, compared safety and effectiveness of stimulation of the dorsal root ganglion (DRG) vs. conventional spinal cord stimulation (SCS) in complex regional pain syndrome (CRPS-I and II) of the lower extremities. This analysis compares cost-effectiveness of three modalities of treatment for CRPS, namely DRG stimulation, SCS, and comprehensive medical management (CMM). MATERIALS AND METHODS: The retrospective cost-utility analysis combined ACCURATE study data with claims data to compare cost-effectiveness between DRG stimulation, SCS, and CMM. Cost-effectiveness was evaluated using a Markov cohort model with ten-year time horizon from the U.S. payer perspective. Incremental cost-effectiveness ratio (ICER) was reported as cost in 2017 U.S. dollars per gain in quality-adjusted life years (QALYs). Willingness-to-pay thresholds of $50,000/QALY and $100,000/QALY were used to define highly cost-effective and cost-effective therapies. RESULTS: Both DRG and SCS provided an increase in QALYs (4.96 ± 1.54 and 4.58 ± 1.35 QALYs, respectively) and an increase in costs ($153,992 ± $36,651 and $128,269 ± $27,771, respectively) compared to CMM (3.58 ± 0.91 QALYs, $106,173 ± $27,005) over the ten-year model lifetime. Both DRG stimulation ($34,695 per QALY) and SCS ($22,084 per QALY) were cost-effective compared to CMM. In the base case, ICER for DRG v SCS was $68,095/QALY. CONCLUSIONS: DRG and SCS are cost-effective treatments for chronic pain secondary to CRPS-I and II compared to CMM. DRG accrued higher cost due to higher conversion from trial to permanent implant and shorter battery life, but DRG was the most beneficial therapy due to more patients receiving permanent implants and experiencing higher quality of life compared to SCS. New DRG technology has improved battery life, which we expect to make DRG more cost-effective compared to both CMM and SCS in the future.