Deer, Timothy R.

Background The efficacy of EVOKE therapy, a closed-loop spinal cord stimulation (SCS) system, has been demonstrated in a double-blinded randomized controlled trial (RCT). RCT evidence, however, may not be generalizable to clinical practice, while limitations of real-world evidence may affect its validity. The aim of this study was to evaluate the effectiveness of EVOKE therapy in routine clinical practice employing a rigorous data collection approach. Methods The ECAP study was a prospective, multicenter, single-arm, pragmatic study that enrolled SCS candidates with chronic, intractable trunk and/or limb pain in 22 US investigational sites. PROMIS-29 questionnaire and objective neurophysiological metrics were collected, and minimal clinically important differences (MCIDs) were used to characterize baseline dysfunction and response to EVOKE therapy both at trial end and maximal analgesic effect post-implant visit. Pre-specified subgroup analyses were conducted based on diagnosis. Results EVOKE therapy observed included a dose ratio of 1.3 and neural dose accuracy of 2.8 μV. Improvements of >1 MCID were observed for all domains and improvements of ≥2 MCIDs were observed for six of the seven domains. Improvements observed at trial end were maintained or improved at post-implant visit, with statistically significant improvement in holistic MCID (MD 0.2, 95% CI 0.1 to 0.4, p=0.004), and a significantly greater proportion of patients considered holistic MCID responders (p=0.047). Subgroup analysis by diagnosis showed similar outcomes. Conclusions EVOKE therapy was associated with clinically meaningful improvements in a real-world chronic pain population across different subgroups and disease pathologies, with effects observed at trial end reproduced at post-implant visit.

Abstract Introduction DISTINCT is a randomized controlled trial evaluating passive recharge burst SCS compared with CMM in improving pain and pain‐related physical function in patients suffering from chronic back pain without prior lumbar surgery, and for whom corrective surgery is not an option. Sub‐analyses of outcome measures are presented for a subset implanted with paddle leads at both 6 and 12 months. Objective To investigate the treatment effect of using BurstDR‐capable SCS in nonsurgical low back pain (NSLBP) patients with paddle leads. Methods An independent board‐certified spine surgeon reviewed each case, confirming a lack of corrective surgical options. Out of 29 sites and 115 implants, 10 sites implanted 50 patients with paddle leads. Primary and secondary endpoints assessed improvements in low back pain intensity (NRS), low back pain‐related disability (ODI), pain catastrophizing (PCS), and patient global impression of change (PGIC). Results Data for patients with NSLBP and implanted with paddle leads are available for 47 and 44 patients at 6 and 12 months, respectively. Patients reported significant reductions in pain relief at 6 and 12 months, decreasing from 7.8 ± 1.2 at baseline to 2.0 ± 1.6 and 2.2 ± 2.2, respectively ( p < 0.0001). Disability was substantially reduced (> 20 points) from severe to mild at 6 and 12 months; ODI reduced from 54.4 ± 15.0 at baseline to 19.9 ± 14.1 and 22.1 ± 13.6, respectively ( p < 0.0001). Pain catastrophizing improved to reflect the average of a non‐chronic pain population; decreased from 27.6 ± 13.1 at baseline to 8.1 ± 8.2 and 7.8 ± 9.9 ( p < 0.0001). 93.2% of patients reported a moderately better‐much‐improved outcome on PGIC. Ten complications occurred in 9 patients, 3 being severe device‐related events. Two explants were required; one due to infection and one due to persistent pain at the IPG site, and one lead‐related event was resolved by surgical repositioning. Conclusions Passive recharge burst using paddle leads provides substantial relief to patients suffering from severe, debilitating, NSLBP. Patients report significant improvements in pain, function, and pain‐related emotional distress. In addition, the rate of adverse events is low, supporting a favorable safety profile.

Abstract 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 β‐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 β‐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.

AbstractBackgroundChronic pelvic pain is a burdensome condition that involves multiple medical sub‐specialties and is often difficult to treat. Sacral stimulation for functional bladder disease has been well established, but little large‐scale evidence exists regarding utilization of other neuromodulation techniques to treat chronic pelvic pain. Emerging evidence does suggest that neuromodulation is a promising treatment, and we aim to characterize the use and efficacy of such techniques for treating chronic pelvic pain syndromes.Materials and MethodsA systematic review of the literature demonstrating the treatment of chronic pelvic pain syndromes with neuromodulation. Abstracts were reviewed and selected for inclusion, including case series, prospective studies, and randomized controlled trials (RCTs). Case studies and publications in abstract only were not included. The reporting for this systematic review follows Preferred Reporting Items for Systematic Reviews and Meta‐Analysis (PRISMA). The literature search was performed using MEDLINE, Embase, Cochrane Library, PubMed, CINAHL, and Scopus.ResultsA total of 50 studies were included in this review, three of which were randomized controlled trials, and the remaining were prospective and retrospective case series. The range of pelvic pain conditions treated included interstitial cystitis, peripheral neuralgia, pudendal neuralgia, gastrointestinal pain, urogenital pain, sacroiliac joint pain, and visceral chronic pelvic pain. We reported on outcomes involving pain, functionality, psychosocial improvement, and medication reduction.ConclusionsNeuromodulation is a growing treatment for various chronic pain syndromes. Peripheral nerve stimulation was the least studied form of stimulation. Posterior tibial nerve stimulation appears to offer short‐term benefit, but long‐term results are challenging. Sacral nerve stimulation is established for use in functional bladder syndromes and appears to offer pain improvement in these patients as well. Dorsal root ganglion stimulation and spinal cord stimulation have been used for a variety of conditions with promising results. Further studies of homogeneous patient populations are necessary before strong recommendations can be made at this time, although pooled analysis may also be impactful.

Abstract 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.

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.

Abstract 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 &gt;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.

Abstract Introduction Dorsal root ganglion stimulation (DRG‐S), has demonstrated superiority in the treatment of complex regional pain syndrome and causalgia. Lead migration and fracture impact DRG‐S therapeutic stability. Lead anchoring reduces DRG‐S lead migration without increasing lead fracture. Lead fracture may be related to lead entrapment in the superficial fascial plane. A novel medialized approach for lead placement and anchoring is presented to address these issues. Methods We suggest an alternative technique for implanting percutaneous DRG‐S leads at the T10‐L5 levels. Results A novel medialized ipsilateral technique for lead placement and anchoring for single, bilateral, and adjacent segment placement is presented. The Tuohy needle puncture site is medial to the pedicle and adjacent to the spinous process, two vertebral levels caudad to the target foramen. Trajectory is maintained in the sagittal plane, to access the caudad interlaminar space near the midline. This technique allows for ipsilateral or contralateral lead placement. After epidural access, the introducer sheath is rotated toward the targeted foramen and advanced. The guidewire followed by the lead is passed, and once lead position is confirmed, tension “S” loops are created, followed by anchoring to the deep fascia. Conclusion We describe a new paramedian technique for DRG‐S lead placement. We propose it will decrease DRG‐S complication rates through anchoring to reduce migration and by avoiding the fascial planes thought to be responsible for fracture. Long‐term outcomes applying our proposed techniques are required for determining the true impact, however, early anecdotal results suggest that these new techniques are favorable.

Introduction Interventional pain procedures have increased in complexity, often requiring longer radiation exposure times and subsequently higher doses. The practicing physician requires an in-depth knowledge and evidence-based knowledge of radiation safety to limit the health risks to themselves, patients and healthcare staff. The objective of this study was to examine current radiation safety practices and knowledge among interventional pain physicians and compare them to evidence-based recommendations. Materials and methods A 49-question survey was developed based on an extensive review of national and international guidelines on radiation safety. The survey was web-based and distributed through the following professional organizations: Association of Pain Program Directors, American Academy of Pain Medicine, American Society of Regional Anesthesia and Pain Medicine, European Society of Regional Anesthesia and Pain Therapy, International Neuromodulation Society, and North American Neuromodulation Society. Responses to radiation safety practices and knowledge questions were evaluated and compared with evidence-based recommendations. An exploratory data analysis examined associations with radiation safety training/education, geographical location, practice type, self-perceived understanding, and fellowship experience. Results Of 708 responding physicians, 93% reported concern over the health effects of radiation, while only 63% had ever received radiation safety training/education. Overall, ≥80% physician compliance with evidence-based radiation safety practice recommendations was demonstrated for only 2/15 survey questions. Physician knowledge of radiation safety principles was low, with 0/10 survey questions having correct response rates ≥80%. Conclusion We have identified deficiencies in the implementation of evidence-based practices and knowledge gaps in radiation safety. Further education and training are warranted for both fellowship training and postgraduate medical practice. The substantial gaps identified should be addressed to better protect physicians, staff and patients from unnecessary exposure to ionizing radiation during interventional pain procedures.

Introduction Spinal cord stimulation is frequently used for the treatment of intractable chronic pain conditions. Trialing of the spinal cord stimulator device is recommended to assess the patient’s response to neurostimulation before permanent implantation. The trial response is often assessed by Numeric Rating Scale changes and patient-reported percentage pain improvement. Using number rating scale changes between prespinal and postspinal cord stimulation trial, a calculated percentage pain improvement can be obtained. The aim of this study was to assess the difference between calculated and patient-reported percentage improvement in pain scale during spinal cord stimulation trials. Methods This study was a retrospective single center review of all spinal cord stimulation trials from January 1 2017 to July 1 2019. A total of 174 patients were included. The paired t-test was used to compare numeric pain scores obtained prestimulation versus poststimulation. The mean difference between methods (patient-reported minus calculated) was compared with zero using the 1-sample t-test. Lin’s concordance correlation coefficient was computed with a 95% CI, calculated using Fisher z-transformation; and a bootstrapping approach was used to compare the concordance correlation coefficient between groups. In all cases, two-tailed tests were used with p<0.05 considered statistically significant. Results Based on prestimulation and poststimulation numeric rating scale scores, the mean±SD calculated percentage improvement in pain scale was 54±28. The mean±SD patient-reported percentage improvement in pain scale was 59±25. The overall 95% limits of agreement for the two methods are −30% to +41%. The overall concordance correlation coefficient was 0.76 (95% CI 0.69 to 0.81). Conclusion Although the two methods are highly correlated, there is substantial lack of agreement between patient-reported and calculated percentage improvement in pain scale, suggesting that these measures should not be used interchangeably for spinal cord stimulator trial outcome assessment. This emphasizes the need for improved metrics to better measure patient response to neuromodulation therapies. Additionally, patient-reported percentage improvement in pain was found to be higher than calculated percentage improvement in pain, potentially highlighting the multidimensional experience of pain and the unpredictability of solely using Numeric Rating Scale scores to assess patient outcomes.