Multicolumn spinal cord stimulation for predominant back pain in failed back surgery syndrome patients: a multicenter randomized controlled trial. Pain. 2019;160:1410-1420. [PMID: 30720582 PMCID: PMC6553955 DOI: 10.1097/j.pain.0000000000001510]

Treatment modalities for patients with Persistent Spinal Pain Syndrome Type II: A systematic review and network meta-analysis

BACKGROUND

Appropriate management of patients with Persistent Spinal Pain Syndrome Type 2 (PSPS-T2) remains challenging. The need for robust evidence for treatment modalities is urgently pressing. The aim of this systematic review and network meta-analysis (NMA) is to compare different treatment modalities for patients with PSPS-T2 on pain intensity.

METHODS

The study protocol was prospectively registered (PROSPERO;CRD42022360160). Four different databases were consulted from database inception to December 18th, 2023. Randomised controlled trials of interventions for PSPS-T2 were included. The revised Cochrane Risk of Bias Tool was used to assess risk of bias. A NMA with standardized mean differences was calculated with pairwise comparisons between all treatment modalities.

RESULTS

Here we include 49 studies in the systematic review and 13 in NMA. A high risk of bias is indicated for 65.3% of the studies. Half of the studies investigate neuromodulation (mainly Spinal Cord Stimulation), 16 explore minimal invasive treatment options (predominantly epidural injections), 6 studies focus on conservative treatments (physiotherapy/cognitive training and medication) and 2 on reoperation. Comparison of neuromodulation versus a combination of conservative and minimal invasive options results in an effect size of 0.45 (95% CI: 0.14-0.76), clearly favouring neuromodulation (z = 2.88; p = 0.004). Additionally, neuromodulation results in a standardised mean difference of 0.36 (95% CI: 0.18-0.53) compared to placebo/sham (z = 4.03; p < 0.0001). No statistically significant difference is found between conservative options and neuromodulation.

CONCLUSIONS

Neuromodulation, followed by conservative treatment options, seems to be the most effective treatment option to obtain pain relief in patients with PSPS-T2. Nevertheless, a personalized approach tailored to individual patient needs is essential for optimizing outcomes, since interventions should be adjusted based on the failure or success of prior therapies.

Peripheral Nerve Stimulation Implantation Combining Ultrasound With Microendoscopy for Management of Chronic Neuropathic Pain: A Case Series Study

BACKGROUND

Peripheral nerve stimulation (PNS) has emerged as a minimally invasive percutaneous procedure addressing neuropathic pain. However, the percutaneous cylindrical lead ultrasound-guided implantation procedure requires expertise that limits widespread PNS utilization. To overcome these challenges, a microinvasive endoscopy device has very recently been developed, enhancing the precision of PNS implantation by providing accurate visualization of the targeted nerve. We aimed to determine the feasibility, safety, clinical effectiveness, and energy consumption of PNS therapy by means of ultrasound guidance combined with microendoscopy.

MATERIALS AND METHODS

This is a retrospective, single-center, single-arm study. Patient recruitment was performed in February and March 2023. Patients with >12 months of upper or lower limb pain presenting with pain >5 of 10 that was refractory to conventional treatments were eligible. Safety was assessed by collecting adverse events and complications related to the PNS implantation with microendoscopy. The Multidimensional Clinical Response Index (MCRI), pain intensity (visual analog scale [VAS]), pain surface (PRISMap Software, PRISMATICS lab, CHU de Poitiers, Poitiers, France), quality of life (EuroQoL 5 dimensions 5 levels [EQ5D-5L]), functional disability (Oswestry Disability Index [ODI]), anxiety and depression (Hospital Anxiety and Depression Scale), and energy consumption were assessed at baseline and at one and three months.

RESULTS

Six patients received PNS, which was implanted through ultrasound guidance combined with microendoscopy. No adverse event was reported during the three-month follow-up. Clinical outcomes (MCRI, VAS, ODI, EQ5D-5L) significantly increased at one- and three-month follow-up. Energy consumption was, on average, 2.6 ± 1.1 μC.s-1 at one-month and 3.3 ± 2.0 μC.s-1 at three-month follow-up.

CONCLUSIONS

Implanted PNS by means of ultrasound combined with microendoscopy was safe and provided clinical benefits with very low energy consumption (15-440 times less than spinal cord stimulation) in patients with upper or lower limb neuropathic pain. Microendoscopy would offer extended PNS indications, overcoming limitations associated with ultrasound alone. Future research is nonetheless needed to provide stronger evidence through randomized controlled trial design.

The Opinion of Healthcare Professionals About a Proposed European Registry of Neuromodulation for Chronic Pain: An Online Survey

INTRODUCTION

During the last decade, the complementary value of real-world data (through registries or medical records) and data from randomized clinical trials has been recognized as increasingly important. In the field of neuromodulation, only a few industry-independent nationwide neuromodulation registries are available. The interest in creating a European registry has increased but without a successful result. The goal of this online survey is to gain further insights into the need for and burden of a European registry for neuromodulation.

MATERIALS AND METHODS

An online survey was developed and distributed during the 3rd Joint Congress of the International Neuromodulation Society European Chapters in September 2023 (Hamburg, Germany). Healthcare professionals were asked to indicate the need for a European registry, the items that should be collected, and the restrictions to access of a European registry.

RESULTS

In total, 125 respondents opened the link to the survey, of whom 104 completed (at least partly) the survey. Of the 104 responses, 91% indicated that there is a need for a European registry, whereas 6% indicated there is no need. The main reasons for establishing a registry on a European level were the possibility of collecting real-world evidence (84%), the potential to collect big data from European patients (82%), to evaluate safety in neuromodulation (70%), and the possibility of reporting yearly on European activity in neuromodulation (51%). Indications for neuromodulation, patient characteristics, and follow-up assessments were most often stated as items that should be collected. Access should not only be granted to implanters but also to nurses, the assessment team, and other physicians, as agreed on by 64%, 52%, and 51%, respectively.

DISCUSSION

More than 90% of the respondents believed that a European registry for neuromodulation is needed, mainly to obtain real-world (big) data about the effectiveness and safety of this therapy. This survey clearly pointed to the need for a European registry for which it seems key to ensure financial and logistical support, in addition to in-depth legal guidance in developing this registry.

Cylindrical vs Paddle Leads in Spinal Cord Stimulation for the Long-term Treatment of Chronic Pain: A Systematic Review and Meta-analysis

OBJECTIVES

This systematic review compares the long-term efficacy of cylindrical-lead spinal cord stimulation (CL-SCS) vs paddle-lead spinal cord stimulation (Paddle-SCS) for chronic pain management.

MATERIALS AND METHODS

We included prospective and retrospective studies with at least ten patients reporting on the efficacy of either lead type. Primary outcomes were pain score reduction (measured by the visual analog scale [VAS] and numeric rating scale [NRS]) and 50% pain relief after at least 12 months. Secondary outcomes included functional disability and complications, such as lead migration and infection rates. Meta-analyses compared effect sizes, while meta-regression and subgroup analyses addressed heterogeneity.

RESULTS

A total of 96 studies, comprising 7726 patients, met the inclusion criteria. Paddle-SCS demonstrated superior pain reduction, with a standardized mean difference (SMD) of 5.37 (95% CI [5.35, 5.38]) compared with CL-SCS, which had an SMD of 4.09 (95% CI [4.08, 4.10]) on the VAS. However, CL-SCS outperformed Paddle-SCS on the NRS, with SMDs of 4.39 vs 2.35, respectively. For 50% pain relief, Paddle-SCS had a success rate of 41.4%, as opposed to 35.4% for CL-SCS. Paddle-SCS showed a lower migration rate (4.3% vs 7.2% for CL-SCS) but higher infection rates (5.0% vs 3.3%).

CONCLUSIONS

Paddle-SCS offers superior pain reduction (as measured by the VAS) and a lower migration rate, but a higher infection risk compared with CL-SCS. CL-SCS showed better outcomes as measured by the NRS. The choice between Paddle-SCS and CL-SCS should be individualized according to patient-specific factors and treatment goals. Further research with rigorous study designs is needed to provide clearer comparisons between these interventions.

Does rehabilitation improve work participation in patients with chronic spinal pain after spinal surgery: a systematic review

OBJECTIVE

Patients with therapy-refractory chronic spinal pain after spinal surgery experience increased disability, resulting in substantial loss of employment and consequently lower quality of life. Despite findings that rehabilitation improves socio-economic outcomes in other chronic pain conditions, evidence for patients with chronic spinal pain after spinal surgery is limited. A systematic review was conducted to provide an overview of rehabilitation interventions and their effectiveness to improve work participation for patients with chronic spinal pain after spinal surgery.

METHODS

MEDLINE (via PubMed), Scopus, Embase, and Web of Science, were systematically searched. Risk of bias was assessed using the modified Downs and Black checklist and GRADE was used to assess certainty of evidence. The review protocol was prospectively registered on PROSPERO (CRD42022346091).

RESULTS

The search yielded 1,289 publications. Full-text screening of 48 articles resulted in the inclusion of 6 publications. The included interventions comprised multiple treatment components, consisting of back school, self-care, functional restoration, multidisciplinary rehabilitation, physiotherapy, and digital care programmes to improve work participation.

CONCLUSION

Rehabilitation to improve return to work for patients with chronic spinal pain after spinal surgery was supported only by low-certainty evidence. Rehabilitation therapies that are personalized and that integrate the patient's work seem most suitable.

Spinal Cord Stimulation Improves Quality of Life for Patients With Chronic Pain-Data From the UK and Ireland National Neuromodulation Registry

INTRODUCTION

Spinal cord stimulation (SCS) is a well-established treatment for chronic pain and is supported by numerous studies. However, some recent articles have questioned its efficacy. This article examines a cohort of >1800 patients with SCS from the UK and Ireland National Neuromodulation Registry. It is intended to provide a "real-world" assessment of efficacy and compare its effects with other procedures performed for painful indications.

MATERIALS AND METHODS

Quality of life (QoL) data (EuroQoL five-level [EQ5D]) and demographic data were extracted from the National Neuromodulation Registry for all patients (N = 1811) who underwent SCS for chronic pain in 27 centers in the UK between February 2018 and July 2022. These were compared with data from the published literature for other commonly performed elective surgical procedures.

RESULTS

The EQ5D utility index increased by a mean of 0.202 in the 1236 patients with paired pre- and postoperative utility scores. The median utility was 0.263 (interquartile range [IQR] = 0.384; n = 1811) preoperatively, whereas at six months after the operation, it was 0.550 (IQR = 0.396; n = 1025), p < 0.0001, Wilcoxon rank sum test. The median utility score at 12 months postoperation was 0.548 (IQR = 0.417; n = 970). There was no difference in utility scores at six months and 12 months after implantation (p = 0.15, Wilcoxon rank sum test). There was a significant improvement in QoL in all five domains of the five-level EQ5D tool at six months after baseline (p < 0.01, for all subcategories), and this was sustained at one year after implantation. The baseline utility was lower than in patients who underwent elective surgery for other painful conditions, and the absolute (and proportionate) increase in utility produced by SCS was greater than that achieved with most other interventions.

CONCLUSIONS

SCS increases the QoL in patients requiring surgery for pain. Similar results were seen regardless of SCS indication. When comparing analogous data bases, SCS produces a greater percentage improvement in EQ5D utility than do many other elective surgical procedures for painful conditions, including spinal surgery and some joint replacements.

Spinal Cord Stimulation vs Medical Management for Chronic Back and Leg Pain: A Systematic Review and Network Meta-Analysis

Importance

Chronic back and lower extremity pain is one of the leading causes of disability worldwide. Spinal cord stimulation (SCS) aims to improve symptoms and quality of life.

Objective

To evaluate the efficacy of SCS therapies compared with conventional medical management (CMM).

Data Sources

MEDLINE, Embase, and Cochrane Library were systematically searched from inception to September 2, 2022.

Study Selection

Selected studies were randomized clinical trials comparing SCS therapies with sham (placebo) and/or CMM or standard treatments for adults with chronic back or leg pain who had not previously used SCS.

Data Extraction and Synthesis

Evidence synthesis estimated odds ratios (ORs) and mean differences (MDs) and their associated credible intervals (CrI) through bayesian network meta-analysis. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline for network meta-analyses was followed.

Main Outcomes and Measures

The primary outcomes were pain-related end points, including pain intensity (measured by visual analog scale) and proportion of patients achieving at least 50% pain relief (responder rate) in the back or leg. Quality of life (measured by EQ-5D index score) and functional disability (measured by the Oswestry Disability Index score) were also considered.

Results

A total of 13 studies of 1561 patients were included in the network meta-analysis comparing conventional and novel SCS therapies with CMM across the 6 outcomes of interest at the 6-month follow-up. Both conventional and novel SCS therapies were associated with superior efficacy compared with CMM in responder rates in back (conventional SCS: OR, 3.00; 95% CrI, 1.49 to 6.72; novel SCS: OR, 8.76; 95% CrI, 3.84 to 22.31), pain intensity in back (conventional SCS: MD, -1.17; 95% CrI, -1.64 to -0.70; novel SCS: MD, -2.34; 95% CrI, -2.96 to -1.73), pain intensity in leg (conventional SCS: MD, -2.89; 95% CrI, -4.03 to -1.81; novel SCS: MD, -4.01; 95% CrI, -5.31 to -2.75), and EQ-5D index score (conventional SCS: MD, 0.15; 95% CrI, 0.09 to 0.21; novel SCS: MD, 0.17; 95% CrI, 0.13 to 0.21). For functional disability, conventional SCS was superior to CMM (MD, -7.10; 95% CrI, -10.91 to -3.36). No statistically significant differences were observed for other comparisons.

Conclusions and Relevance

This systematic review and network meta-analysis found that SCS therapies for treatment of chronic pain in back and/or lower extremities were associated with greater improvements in pain compared with CMM. These findings highlight the potential of SCS therapies as an effective and valuable option in chronic pain management.

Hidden influence? Unmasking conflicts of interest from randomized clinical trials on spinal cord stimulation for chronic pain

BACKGROUND

Randomized clinical trials (RCTs) are considered the gold standard for evaluating the efficacy of healthcare interventions. However, conflicts of interest (COIs) can compromise the scientific integrity in these trials. This study characterized COIs in RCTs on spinal cord stimulation for chronic pain, focusing on the prevalence, disclosure, and monetary value of COIs.

METHODS

This cross-sectional study analyzed RCTs published from January 1, 2013 to July 27, 2023. Primary outcomes included the presence, disclosure, and monetary value of COIs, while secondary outcomes assessed the presence of direct/indirect COIs, sponsor access to data, and associations between COIs and select variables, including journal impact factor, publication year, and study outcomes.

RESULTS

Of 38 RCTs, 30 (78.9%) reported COIs. On average, 35.6% of authors per RCT had at least one COI, with a mean of 0.7 COIs per author. The mean annual monetary value of COIs was US$41,157.83 per author per RCT. 29 RCTs (76.3%) had undisclosed COIs, with an average of 24.2% of authors per RCT having undisclosed COIs. Sponsor access to data was reported in 67.6% of RCTs. No associations were observed between the mean percentage of authors with COIs and the monetary value of COIs and select dependent variables (impact factor, publication year, and study outcomes).

CONCLUSIONS

A substantial majority of RCTs reported COIs with many authors having undisclosed conflicts, highlighting the need for stringent COI disclosure guidelines to maintain research integrity. Expanding COI registry systems globally and increasing non-industry funding are crucial steps toward enhancing transparency and reducing biases in medical research.

Comparative Efficacy of Spinal Cord Stimulation in the Management of Acute Pain and Chronic Pain Related to Failed Back Surgery Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Spinal cord stimulation (SCS) is a well-established treatment for chronic pain. However, its potential in acute pain management requires further investigation. The goal of this review is to assess and compare the effectiveness of SCS for managing acute postoperative pain against chronic pain associated with failed back surgery syndrome (FBSS). A comprehensive search of databases identified randomized controlled trials (RCTs) that examined SCS for both acute and chronic pain associated with FBSS. Pain relief was measured using the Visual Analog Scale (VAS) and Numeric Rating Scale (NRS). Study quality was evaluated using the Jadad score and Cochrane risk of bias tool. Evidence suggests that SCS significantly reduces acute pain, achieving over a 50% reduction in VAS scores. For chronic pain associated with FBSS, SCS demonstrated substantial efficacy, with a mean reduction of -2.45 on pain scales compared to baseline. When compared to optimal medical management (OMM), SCS was more effective, showing a mean reduction of -1.17 in pain scores for FBSS. Overall, SCS offers significant benefits in managing chronic pain, particularly in FBSS, by reducing pain intensity and opioid use. While the initial findings for acute pain relief are promising, further high-quality RCTs are needed to better understand SCS's role in preventing the transition from acute to chronic pain. Continued research into optimizing patient selection and stimulation parameters will be essential to improve therapeutic outcomes in both acute and chronic pain management.

Multicolumn Spinal Cord Stimulation for Chronic Back and Leg Pain in Patients with Failed Back Surgery Syndrome: A Systematic Review and Meta-Analysis

Introduction

Failed Back Surgery Syndrome (FBSS) presents a formidable challenge, marked by the persistence of chronic lower back pain and leg pain despite undergoing surgical interventions. Multicolumn spinal cord stimulation (m-SCS) has recently emerged as a promising therapeutic strategy for addressing the pain associated with FBSS. This meta-analysis aims to study the efficacy of m-SCS in mitigating chronic back and leg pain among patients with FBSS.

Methods

A comprehensive search of electronic databases (PubMed, Web of Science, Scopus, Cochrane Library) was conducted to identify relevant studies published up to October 25th, 2023. Inclusion criteria encompassed randomized controlled trials and cohort studies evaluating the outcomes of m-SCS in patients with FBSS. The primary outcome measured was the Visual Analog Scale (VAS) score for low back and leg pain at baseline, six months, and 12 months.

Results

A total of eight studies, including 271 patients, were analyzed. At six months, there was a statistically significant reduction in the VAS scores for low back pain (MD, 4.76; 95% CI, 3.78 to 5.74) and leg pain (MD, 4.41; 95% CI, 2.93 to 5.90) compared to baseline. Similarly, at 12 months, there was a statistically significant reduction in the VAS scores for low back pain (MD, 4.77; 95% CI, 4.34 to 5.20) and leg pain (MD, 2.78; 95% CI, 0.72 to 4.85) compared to baseline.

Conclusion

m-SCS effectively manages chronic back and leg pain in FBSS patients, providing sustained pain relief. Studies with more extended follow-up periods and qualitative analysis for the functional outcomes and overall improvement for the patients with FBSS are recommended.

Network Meta-analysis and Economic Evaluation of Neurostimulation Interventions for Chronic Nonsurgical Refractory Back Pain

OBJECTIVES

Different types of spinal cord stimulation (SCS) have been evaluated for the management of chronic nonsurgical refractory back pain (NSRBP). A direct comparison between the different types of SCS or between closed-loop SCS with conventional medical management (CMM) for patients with NSRBP has not been previously conducted, and therefore, their relative effectiveness and cost-effectiveness remain unknown. The aim of this study was to perform a systematic review, network meta-analysis (NMA) and economic evaluation of closed-loop SCS compared with fixed-output SCS and CMM for patients with NSRBP.

METHODS

Databases were searched to September 8, 2023. Randomized controlled trials of SCS for NSRBP were included. The results of the studies were combined using fixed-effect NMA models. A cost-utility analysis was performed from the perspective of the UK National Health Service with results reported as incremental cost per quality-adjusted life-year (QALY).

RESULTS

Closed-loop SCS resulted in statistically and clinically significant reductions in pain intensity (mean difference [MD] 32.72 [95% CrI 15.69-49.78]) and improvements in secondary outcomes (Oswestry Disability Index [ODI] and health-related quality of life [HRQoL]) compared with fixed-output SCS at 6-month follow-up. Compared with CMM, both closed-loop and fixed-output SCS resulted in statistically and clinically significant reductions in pain intensity (closed-loop SCS vs. CMM MD 101.58 [95% CrI 83.73-119.48]; fixed-output SCS versus CMM MD 68.86 [95% CrI 63.43-74.31]) and improvements in secondary outcomes (ODI and HRQoL). Cost-utility analysis showed that closed-loop SCS dominates fixed-output SCS and CMM, and fixed-output SCS also dominates CMM.

DISCUSSION

Current evidence showed that closed-loop and fixed-output SCS provide more benefits and cost-savings compared with CMM for patients with NSRBP.

Pain medication tapering for patients with Persistent Spinal Pain Syndrome Type II, treated with Spinal Cord Stimulation: A RCT-study protocol of the PIANISSIMO study

BACKGROUND

Spinal Cord Stimulation (SCS) may provide pain relief in patients with therapy-refractory Persistent Spinal Pain Syndrome Type II (PSPS-T2). Despite the evidence that SCS can reduce disability and reduce pain medication usage, only 25% of the patients is able to completely omit pain medication usage after 12 months of SCS. To tackle the high burden of patients who consume a lot of pain medication, tapering programs could be initiated before starting a trajectory with SCS. The current objective is to examine whether a pain medication tapering program before SCS alters disability in PSPS-T2 patients compared to no tapering program.

METHODS AND DESIGN

A three-arm, parallel-group multicenter randomized controlled trial will be conducted including 195 patients who will be randomized (1:1:1) to either (a) a standardized pain medication tapering program, (b) a personalized pain medication tapering program, or (c) no tapering program before SCS implantation, all with a follow-up period until 12 months after implantation. The primary outcome is disability. The secondary outcomes are pain intensity, health-related quality of life, participation, domains affected by substance use, anxiety and depression, medication usage, psychological constructs, sleep, symptoms of central sensitization, and healthcare expenditure.

DISCUSSION

Within the PIANISSIMO project we propose a way to reduce the risks of adverse events, medication-induced hyperalgesia, tolerance, and dependence by providing pain medication tapering before SCS. Due to the lack of a commonly accepted in-hospital tapering approach, two different tapering programs will be evaluated in this study. If pain medication tapering programs are deemed to be more effective than no tapering on disability, this would add to the evidence towards an improved patient-centered care model in this patient group and set a clear path to advocate for pain medication tapering before SCS as the new standard treatment guideline for these patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05861609. Registered on May 17, 2023.

Spinal Cord Stimulator Inequities Within the US Military Health System

OBJECTIVES

Although studies have described inequities in spinal cord stimulation (SCS) receipt, there is a lack of information to inform system-level changes to support health care equity. This study evaluated whether Black patients exhaust more treatment options than do White patients, before receiving SCS.

MATERIALS AND METHODS

This retrospective cohort study included claims data of Black and non-Latinx White patients who were active-duty service members or military retirees who received a persistent spinal pain syndrome (PSPS) diagnosis associated with back surgery within the US Military Health System, January 2017 to January 2020 (N = 8753). A generalized linear model examined predictors of SCS receipt within two years of diagnosis, including the interaction between race and number of pain-treatment types received.

RESULTS

In the generalized linear model, Black patients (10.3% [8.7%, 12.0%]) were less likely to receive SCS than were White patients (13.6% [12.7%, 14.6%]) The interaction term was significant; White patients who received zero to three different types of treatments were more likely to receive SCS than were Black patients who received zero to three treatments, whereas Black and White patients who received >three treatments had similar likelihoods of receiving a SCS.

CONCLUSIONS

In a health care system with intended universal access, White patients diagnosed with PSPS tried fewer treatment types before receiving SCS, whereas the number of treatment types tried was not significantly related to SCS receipt in Black patients. Overall, Black patients received SCS less often than did White patients. Findings indicate the need for structured referral pathways, provider evaluation on equity metrics, and top-down support.

Emotional and psychosocial function after dorsal column spinal cord stimulator implantation: a systematic review and meta-analysis

BACKGROUND

The efficacy of spinal cord stimulation (SCS) in chronic pain studies is traditionally assessed by pain scores, which do not reflect the multidimensional nature of pain perception. Despite the evidence of SCS's influence on emotional functioning comprehensive assessments of its effect remain lacking.

OBJECTIVE

To assess changes in emotional and psychosocial functioning in patients who underwent SCS implantation for chronic pain.

EVIDENCE REVIEW

Ovid MEDLINE, EMBASE, PsychINFO, Cochrane CENTRAL and Scopus databases were searched for original peer-reviewed publications reporting emotional functioning after SCS. The primary outcomes were a pooled mean difference (MD) in anxiety, depression, global functioning, mental well-being and pain catastrophizing at 12 months. The Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) was used to determine the quality of evidence.

FINDINGS

Thirty-two studies were included in the primary analysis. Statistically significant improvements were observed in anxiety (MD -2.16; 95% CI -2.84 to -1.49; p<0.001), depression (MD -4.66; 95% CI -6.26 to -3.06; p<0.001), global functioning (MD 20.30; 95% CI 14.69 to 25.90; p<0.001), mental well-being (MD 4.95; 95% CI 3.60 to 6.31; p<0.001), and pain catastrophizing (MD -12.09; 95% CI -14.94 to -9.23; p<0.001). Subgroup analyses revealed differences in Global Assessment of Functioning and mental well-being based on study design and in depression based on waveform paradigm.

CONCLUSION

The results highlight the statistically and clinically significant improvements in emotional and psychosocial outcomes in patients with chronic pain undergoing SCS therapy. However, these results need to be interpreted with caution due to the very low certainty of evidence per the GRADE criteria.

PROSPERO REGISTRATION

CRD42023446326.

Does industry funding and study location impact findings from randomized controlled trials of spinal cord stimulation? A systematic review and meta-analysis

BACKGROUND/IMPORTANCE

Concerns have been raised that effects observed in studies of spinal cord stimulation (SCS) funded by industry have not been replicated in non-industry-funded studies and that findings may differ based on geographical location where the study was conducted.

OBJECTIVE

To investigate the impact of industry funding and geographical location on pain intensity, function, health-related quality of life and adverse events reported in randomized controlled trials (RCTs) of SCS.

EVIDENCE REVIEW

Systematic review conducted using MEDLINE, CENTRAL, EMBASE and WikiStim databases until September 2022. Parallel-group RCTs evaluating SCS for patients with neuropathic pain were included. Results of studies were combined in random-effects meta-analysis using the generic-inverse variance method. Subgroup meta-analyses were conducted according to funding source and study location. Risk of bias was assessed using Cochrane RoB 2.0 tool.

FINDINGS

Twenty-nine reports of 17 RCTs (1823 participants) were included. For the comparison of SCS with usual care, test for subgroup differences indicate no significant differences (p=0.48, moderate certainty evidence) in pain intensity score at 6 months for studies with no funding or funding not disclosed (pooled mean difference (MD) -1.96 (95% CI -3.23 to -0.69; 95% prediction interval (PI) not estimable, I2=0%, τ2=0)), industry funding (pooled MD -2.70 (95% CI -4.29 to -1.11; 95% PI -8.75 to 3.35, I2=97%, τ2=2.96) or non-industry funding (MD -3.09 (95% CI -4.47 to -1.72); 95% PI, I2 and τ2 not applicable). Studies with industry funding for the comparison of high-frequency SCS (HF-SCS) with low-frequency SCS (LF-SCS) showed statistically significant advantages for HF-SCS compared to LF-SCS while studies with no funding showed no differences between HF-SCS and LF-SCS (low certainty evidence).

CONCLUSION

All outcomes of SCS versus usual care were not significantly different between studies funded by industry and those independent from industry. Pain intensity score and change in pain intensity from baseline for comparisons of HF-SCS to LF-SCS seem to be impacted by industry funding.

Diagnosis and Treatment of Low Back Pain: Synopsis of the 2021 US Department of Veterans Affairs and US Department of Defense Clinical Practice Guideline

ABSTRACT

Low back pain is a significant issue in the US Department of Veterans Affairs and Department of Defense populations as well as the general US population at large. This type of pain can be distressing to those who experience its effects, leading patients to seek relief of their symptoms. In 2022, leadership within the US Department of Veterans Affairs and US Department of Defense approved a joint clinical practice guideline for the management of low back pain. The guideline provides evidence-based recommendations for assessing and managing low back pain. Development of the guideline included a systematic evidence review, which was guided by 12 key questions. A multidisciplinary team, which included clinical stakeholders, reviewed the evidence that was retrieved and developed 39 recommendations using the Grading of Recommendations Assessment, Development, and Evaluation system. The scope of the clinical practice guideline is broad; however, the authors have focused on key recommendations that are important for clinicians in the evaluation and nonoperative treatment of low back pain, including pharmacologic therapies and both noninvasive and invasive nonpharmacologic treatments.

Healthcare resource utilization for chronic low back pain among high-utilizers

BACKGROUND

Chronic low back pain is a leading cause of morbidity and is among the largest cost drivers for the healthcare system. Research on healthcare resource utilization of patients with low back pain who are not surgical candidates is limited, and few studies follow individuals who generate high healthcare costs over time.

PURPOSE

This claims study aimed to identify patients with high-impact mechanical, chronic low back pain (CLBP), quantify their low back pain-related health resource utilization, and explore associated patient characteristics. We hypothesize that patients in the top quartile of healthcare resource utilization in the second year after initial diagnosis will continue to generate considerable back pain-related costs in subsequent years.

STUDY DESIGN/SETTING

IBM MarketScan Research Databases from 2009-2019 were retrospectively analyzed.

PATIENT SAMPLE

Adults in the United States with an initial diagnosis of low back pain between 2010 and 2014 who did not have cancer, spine surgery, recent pregnancy, or inflammatory spine conditions, were identified using the International Classification of Diseases (ICD) and Current Procedural Terminology (CPT) codes. To ensure patients had chronic low back pain, it was required that individuals had additional claims with a low back pain diagnosis 6 to 12 and 12 to 24 months after initial diagnosis.

OUTCOME MEASURES

Cost and utilization of inpatient visits, outpatient visits, emergency room visits, pharmacologic and nonpharmacologic treatment options and imaging for chronic low back pain.

METHODS

Annual back pain-related costs and the use of pharmacologic and nonpharmacologic treatments for 5 years were analyzed. Logistic regression was utilized to identify factors associated with persistent high spending.

RESULTS

Of 16,917 individuals who met the criteria for chronic low back pain, 4,229 met the criteria for having high healthcare utilization, defined as being in the top quartile of back pain-related costs in the 12 to 24 months after their initial diagnosis. The mean and median back pain-related cost in the first year after an initial diagnosis was $7,112 (SD $9,670) and $4,405 (Q1 $2,147, Q3 $8,461). Mean and median back pain related costs in the second year were $11,989 (SD $20,316) and $5,935 (Q1 $3,892, Q3 $10,678). Costs continued to be incurred in years 3 to 5 at a reduced rate. The cumulative mean cost for back pain over the 5 years following the initial diagnosis was $31,459 (SD $39,545). The majority of costs were from outpatient services. Almost a quarter of the high utilizers remained in the top quartile of back pain-related costs during years 3 to 5 after the initial diagnosis, and another 19% remained in the top quartile for 2 of the 3 subsequent years. For these two groups combined (42%), the 5-year cumulative mean cost for back pain was $43,818 (SD $48,270). Patient characteristics associated with a higher likelihood of remaining as high utilizers were diabetes, having a greater number of outpatient visits and pharmacologic prescriptions, and lower utilization of imaging services.

CONCLUSION

This is one of the first studies to use an administrative claims database to identify high healthcare resource utilizers among a population of United States individuals with nonsurgical, chronic low back pain and follow their utilization over time. There was a population of individuals who continued to experience high costs 5 years beyond their initial diagnosis, and the majority of individuals continued to seek outpatient services. Further longitudinal claims research that incorporates symptom severity is needed to understand the economic implications of this condition.

Long-term efficacy of spinal cord stimulation for chronic primary neuropathic pain in the contemporary era: a systematic review and meta-analysis

INTRODUCTION

Spinal cord stimulation (SCS) is a modern neuromodulation technique extensively proven to be an effective modality for treatment of chronic neuropathic pain. It has been mainly studied for complex regional pain syndrome (CRPS) and failed back surgery syndrome (FBSS) and recent data almost uniformly establishes its statistically significant positive therapeutic results. It has also been compared with other available treatment modalities across various studies. However, long term data on maintenance of its efficacious potential remains less explored. Few studies have reported data on long follow-up times (>= 12 months) and have compared its efficacy with other treatment options for chronic pain, respectively. Our study pools and analyzes the available data and compares SCS with other treatment options. It also analyzes the efficacy of SCS in long term management of patients with chronic pain.

EVIDENCE ACQUISITION

We reviewed all the data available on MEDLINE, Embase and Cochrane CENTRAL using a search strategy designed to fit our pre-set inclusion and exclusion criteria. Both single-arm and double-arm studies were included. The primary outcome was defined as decrease of visual analogue scale (VAS) by >50% at 6, 12 and/or 24 months after SCS.

EVIDENCE SYNTHESIS

According to the pooled data of double-arm studies, SCS has unanimously proven its superiority over other treatment options at 6 months follow-up; however it fails to prove statistically significant difference in results at longer treatment intervals. Dorsal root ganglion stimulation, a relatively recent technique with the same underlying physiologic mechanisms as SCS, showed far more promising results than SCS. Single-arm studies show around 70% patients experiencing greater than 50% reduction in their VAS scores at 6 and 12 months.

CONCLUSIONS

SCS is a viable option for management of chronic neuropathic pain secondary to FBSS and CRPS. However, data available for its long term efficacy remains scarce and show no further statistically significant results.

Factors Predicting Clinically Relevant Pain Relief After Spinal Cord Stimulation for Patients With Chronic Low Back and/or Leg Pain: A Systematic Review With Meta-Analysis and Meta-Regression

RATIONALE

To optimize results with spinal cord stimulation (SCS) for chronic low back pain (CLBP) and/or leg pain, including persistent spinal pain syndrome (PSPS), careful patient selection based on proved predictive factors is essential. Unfortunately, the necessary selection process required to optimize outcomes of SCS remains challenging.

OBJECTIVE

This review aimed to evaluate predictive factors of clinically relevant pain relief after SCS for patients with CLBP and/or radicular leg pain, including PSPS.

MATERIALS AND METHODS

In August 2023, PubMed, Cinahl, Cochrane, and EMBASE were searched to identify studies published between January 2010 and August 2023. Studies reporting the percentage of patients with ≥50% pain relief after SCS in patients with CLBP and leg pain, including PSPS at 12 or 24 months, were included. Meta-analysis was conducted to pool results for back, leg, and general pain relief. Predictive factors for pain relief after 12 months were examined using univariable and multivariable meta-regression.

RESULTS

A total of 27 studies (2220 patients) were included for further analysis. The mean percentages of patients with substantial pain relief were 68% for leg pain, 63% for back pain, and 73% for general pain at 12 months follow-up, and 63% for leg pain, 59% for back pain, and 71% for general pain at 24 months follow-up assessment. The implantation method and baseline Oswestry Disability Index made the multivariable meta-regression model for ≥50% back pain relief. Sex and pain duration made the final model for ≥50% leg pain relief. Variable stimulation and implantation method made the final model for general pain relief.

CONCLUSIONS

This review supports SCS as an effective pain-relieving treatment for CLBP and/or leg pain, and models were developed to predict substantial back and leg pain relief. To provide high-grade evidence for predictive factors, SCS studies of high quality are needed in which standardized factors predictive of SCS success, based on in-patient improvements, are monitored and reported.

Effectiveness of Cognitive Functional Therapy Versus Core Exercises and Manual Therapy in Patients With Chronic Low Back Pain After Spinal Surgery: Randomized Controlled Trial

OBJECTIVE

Our aim was to investigate whether cognitive functional therapy (CFT) was more effective than core exercises and manual therapy (CORE-MT) in improving pain and function for patients with chronic low back pain after spinal surgery.

METHODS

This study was a randomized controlled superiority trial in a university hospital and a private physical therapist clinic in Santa Catarina, Brazil. Eighty participants who were 18 to 75 years old and had chronic low back pain after spinal surgery received 4 to 12 treatment sessions of CFT or CORE-MT once per week for a maximum period of 12 weeks. Primary outcomes were pain intensity (numeric pain rating scale, scored from 0 to 10) and function (Patient-Specific Functional Scale, scored from 0 to 10) after intervention.

RESULTS

We obtained primary outcome data for 75 participants (93.7%). CFT was more effective, with a large effect size, than CORE-MT in reducing pain intensity (mean difference [MD] = 2.42; 95% CI = 1.69-3.14; effect size [d] = 0.85) and improving function (MD = -2.47; 95% CI = -3.08 to -1.87; effect size = 0.95) after intervention (mean = 10.4 weeks [standard deviation = 2.17] after the beginning of treatment). The differences were maintained at 22 weeks for pain intensity (MD = 1.64; 95% CI = 0.98-2.3; effect size = 0.68) and function (MD = -2.01; 95% CI = -2.6 to -1.41; effect size = 0.81).

CONCLUSION

CFT was more effective than CORE-MT, with large effect sizes, and may be an option for patients with chronic low back pain after spinal surgery.

IMPACT

CFT reduces pain and improves function, with large effect sizes, compared with CORE-MT. The difference between CFT and CORE-MT was sustained at the midterm follow-up. Treatment with CFT may be an option for patients with chronic low back pain after spinal surgery.

Real World Characterization of Chronic Pain, Success Rates and Implant Rates: Evidence from a Digital Health Platform of Patients Undergoing Spinal Cord Stimulation Evaluations

Spinal cord stimulation is an effective treatment for those experiencing chronic back and leg pain but requires a temporary evaluation period (SCSeval) before permanent implantation. We present real-world data from 7,000 patients who underwent SCSeval while utilizing a mobile digital health platform for education, feedback, and outcomes collection during their surgical journey. We analyzed preoperative patient demographics, characterized patient pain profiles using the patient-reported outcomes measurement information system-29 surveys, and calculated the rates of conversion from temporary to permanent spinal cord stimulation (SCS) implantation. Between August 1, 2021, and March 2, 2023, 7,000 patients (mean age 59.1, 59.6% female) underwent SCSeval procedures while utilizing a mobile application. Patients commonly experienced aching, sharp, stabbing, tingling, numb, and burning pain. Patients had tried multiple prior therapies and wanted to reduce their use of opioids and pain medications. Overall, 90.1% of the patients had a successful SCSeval, and 80.4% of those converted to permanent implant, with the highest rates among those who underwent SCSeval in a hospital setting. There was a significant improvement in all domains of pain as evaluated by pre and postoperative patient-reported outcomes measurement information system-29 surveys. This study supports the use of digital health technology as part of the SCS journey to improve the patient experience and allow for robust patient-reported outcomes collection. The overall rate of SCSeval to permanent SCS in our study of 72.4% was higher than national rates of 64%, suggesting that an app may allow clinicians to better quantify changes in chronic pain and provide more insight into choosing to implant SCS permanently. PERSPECTIVE: This article presents real-world evidence from a digital health platform for therapy education and outcomes collection from patients undergoing spinal cord stimulation evaluation procedures. Such tools could allow for better pain characterization and allow for more nuanced tracking of patient outcomes among those with chronic pain.

Should we Oppose or Combine Waveforms for Spinal Cord Stimulation in PSPS-T2 Patients? A Prospective Randomized Crossover Trial (MULTIWAVE Study)

Refractory persistent spinal pain syndrome after surgery (PSPS-T2) can be successfully addressed by spinal cord stimulation (SCS). While conventional stimulation generates paresthesia, recent systems enable the delivery of paresthesia-free stimulation. Studies have claimed non-inferiority/superiority of selected paresthesia-free stimulation compared with paresthesia-based stimulation, but the comparative efficacy between different waveforms still needs to be determined in a given patient. We designed a randomized controlled 3-month crossover trial to compare pain relief of paresthesia-based stimulation versus high frequency versus burst in 28 PSPS-T2 patients implanted with multiwave SCS systems. Our secondary objectives were to determine the efficacy of these 3 waveforms on pain surface, quality of life, functional capacity, psychological distress, and validated composite multidimensional clinical response index to provide holistic comparisons at 3-, 6-, 9-, and 15-month post-randomization. The preferred stimulation modality was documented during the follow-up periods. No difference between the waveforms was observed in this study (P = .08). SCS led to significant pain relief, quality of life improvement, improvement of multidimensional clinical response index, and of all other clinical outcomes at all follow-up visits. Forty-four percent of the patients chose to keep the paresthesia-based stimulation modality after the 15-month follow-up period. By giving the possibility to switch and/or to combine several waveforms, the overall rate of SCS responders further increased with 25%. In this study, high frequency or burst do not appear superior to paresthesia-based stimulation, wherefore paresthesia-based stimulation should still be considered as a valid option. However, combining paresthesia-based stimulation with paresthesia-free stimulation, through personalized multiwave therapy, might significantly improve SCS responses. PERSPECTIVE: This article assesses clinical SCS efficacy on pain relief, by comparing paresthesia-based stimulation and paresthesia-free stimulation (including high frequency and burst) modalities in patient presenting with PSPS-T2. Switching and/or combining waveforms contribute to increasing the global SCS responders rate.

Current Neurostimulation Therapies for Chronic Pain Conditions

PURPOSE OF REVIEW

Neurostimulation treatment options have become more commonly used for chronic pain conditions refractory to these options. In this review, we characterize current neurostimulation therapies for chronic pain conditions and provide an analysis of their effectiveness and clinical adoption. This manuscript will inform clinicians of treatment options for chronic pain.

RECENT FINDINGS

Non-invasive neurostimulation includes transcranial direct current stimulation and repetitive transcranial magnetic stimulation, while more invasive options include spinal cord stimulation (SCS), peripheral nerve stimulation (PNS), dorsal root ganglion stimulation, motor cortex stimulation, and deep brain stimulation. Developments in transcranial direct current stimulation, repetitive transcranial magnetic stimulation, spinal cord stimulation, and peripheral nerve stimulation render these modalities most promising for the alleviating chronic pain. Neurostimulation for chronic pain involves non-invasive and invasive modalities with varying efficacy. Well-designed randomized controlled trials are required to delineate the outcomes of neurostimulatory modalities more precisely.

Does lumbar spinal decompression or fusion surgery influence outcome parameters in patients with intrathecal morphine treatment for persistent spinal pain syndrome type 2 (PSPS-T2)

OBJECTIVES

Intrathecal morphine pump (ITMP) infusion therapy is efficient in managing chronic pain refractory to standard treatment. This study evaluates pain relief and improvement of quality of life in chronic pain patients after intrathecal morphine pump implantation for treatment of persistent pain after lumbar spinal fusion surgery and lumbar spinal decompression alone.

METHODS

Forty three chronic pain patients that received an ITMP at our department between 2009 and 2019 were retrospectively analyzed divided into 2 cohorts (lumbar spinal fusion surgery and lumbar spinal decompression alone). Pain intensity was evaluated using the numeric rating scale (NRS), quality of life was assessed by EQ-5D-3L, mental health was assessed by Beck Depression Inventory (BDI-V), and Pain Catastrophizing Scale (PCS). Morphine dosage was assessed over time. Data was collected preoperatively, 6 and 24 months postoperatively. Statistical analysis was performed using Friedman's analysis of variance to evaluate the development of NRS, PCS, BDI and EQ-5D-3L over time and Mann-Whitney-U-test for the differences between these parameters in the different cohorts. A two-sided p-value <0.05 was considered statistically significant.

RESULTS

Median age was 64 years (IQR25-75 56-71 years). NRS, EQ-5D-3L, BDI-V, and PCS showed a significant overall improvement after 6 and 24 months compared to baseline data (p<0.001). No statistically significant differences between patients with lumbar spinal fusion surgery and lumbar spinal decompression alone were seen. Furthermore, no statistically significant differences for age and gender were seen. The initially administered median morphine dosage was significantly higher in the fusion group (3.0 mg/day; IQR25-75 1.5-4.2 mg/day) compared to the decompression-alone group (1.5 mg/day; IQR25-75 1.0-2.6 mg/day); (p=0.027).

CONCLUSIONS

This retrospective study showed that ITMP have a major long-term impact on pain relief, improve the quality of life, psychological distress, as well as pain catastrophizing in patients with chronic pain following lumbar spinal surgery independent of the previous surgical procedure. After ITMP implantation initial median morphine dosage seems to be significantly higher after spinal fusion compared to decompressive surgery alone.

Neurostimulation for Chronic Pain: A Systematic Review of High-Quality Randomized Controlled Trials With Long-Term Follow-Up

OBJECTIVE

This study aimed to review the best evidence on the long-term efficacy of neurostimulation for chronic pain.

MATERIALS AND METHODS

We systematically reviewed PubMed, CENTRAL, and WikiStim for studies published between the inception of the data bases and July 21, 2022. Randomized controlled trials (RCTs) with a minimum of one-year follow-up that were of high methodologic quality as ascertained using the Delphi list criteria were included in the evidence synthesis. The primary outcome was long-term reduction in pain intensity, and the secondary outcomes were all other reported outcomes. Level of recommendation was graded from I to III, with level I being the highest level of recommendation.

RESULTS

Of the 7119 records screened, 24 RCTs were included in the evidence synthesis. Therapies with recommendations for their usage include pulsed radiofrequency (PRF) for postherpetic neuralgia, transcutaneous electrical nerve stimulation for trigeminal neuralgia, motor cortex stimulation for neuropathic pain and poststroke pain, deep brain stimulation for cluster headache, sphenopalatine ganglion stimulation for cluster headache, occipital nerve stimulation for migraine, peripheral nerve field stimulation for back pain, and spinal cord stimulation (SCS) for back and leg pain, nonsurgical back pain, persistent spinal pain syndrome, and painful diabetic neuropathy. Closed-loop SCS is recommended over open-loop SCS for back and leg pain. SCS is recommended over PRF for postherpetic neuralgia. Dorsal root ganglion stimulation is recommended over SCS for complex regional pain syndrome.

CONCLUSIONS

Neurostimulation is generally effective in the long term as an adjunctive treatment for chronic pain. Future studies should evaluate whether the multidisciplinary management of the physical perception of pain, affect, and social stressors is superior to their management alone.

Incidence of Neuraxial and Non-Neuraxial Hematoma Complications From Spinal Cord Stimulator Surgery: Systematic Review and Proportional Meta-Analysis

OBJECTIVE

The goal of this meta-analysis was to estimate the incidence of total hematomas, neuraxial hematomas, and non-neuraxial hematomas in patients who underwent temporary spinal cord stimulator (SCS) lead trial placement and permanent implantation of SCS leads and internal pulse generator (IPG).

MATERIALS AND METHODS

A comprehensive search was conducted of databases of any publications before October 21, 2021. Eligible study designs included randomized control trials and prospective or retrospective observational studies with more than ten patients. The primary outcome variables were the incidences of total hematomas, neuraxial hematomas, and non-neuraxial hematomas in patients with SCS. These dichotomous categorical outcomes were abstracted from studies after Freeman-Tukey arcsine square root transformation using random-effects meta-analysis (DerSimonian and Laird method). Pooled incidence rates and 95% CIs were calculated for each outcome variable.

RESULTS

A total of 40 studies met the inclusion criteria. Included in the neuraxial and non-neuraxial hematoma analyses were 4751 patients and 3862 patients, respectively. The pooled incidence of any hematoma in patients with SCS was 0.81% (95% CI, 0.45%-1.27%). The pooled incidence of neuraxial hematoma in patients with SCS was 0.32% (95% CI, 0.18%-0.50%). This included primarily epidural hematomas (11/4751) but also comprised an intracranial hemorrhage in a patient on enoxaparin bridge therapy from warfarin and one patient not on anticoagulation with an intracranial subdural hematoma that resulted in death. The pooled incidence of non-neuraxial hematomas in patients with SCS was 0.59% (95% CI, 0.29%-1.00%).

CONCLUSION

The overall incidence of hematomas in patients with temporary SCS trial lead placement and permanent SCS/IPG implantations is less than 1%. Furthermore, the incidence of neuraxial hematomas is less than 0.5%, which is of particular interest given the potential devastating consequences of this complication. The results of this study can be used to inform patients and implanting physicians on hematoma complications from SCS and highlight that the benefits of SCS outweigh the hematoma risks if anticoagulation is appropriately managed perioperatively.

Correlation Between Abdominal Wall Stimulation and Spinal Cord Stimulator Tip Location: A Nonrandomized Clinical Trial

OBJECTIVES

This study aimed to investigate the correlation between the vertebral level of paddle placement and abdominal wall stimulation (AWS) after differential target multiplexed spinal cord stimulation (SCS) to improve the safety and effectiveness of SCS for patients with chronic pain, particularly those with low back pain (LBP).

MATERIALS AND METHODS

The Correlation Between Abdominal Wall Stimulation and Spinal Cord Stimulator Tip Location study was a nonrandomized clinical trial that included 24 patients with SCS for persistent spinal pain syndrome (PSPS) type 2 (trial ID: NCT05565469). The intervention involved increasing stimulation amplitude to a maximum tolerable value and obtaining numerical rating scores for AWS. The primary outcome measure was the association between AWS, the neurostimulator tip, and conus medullaris location, whereas the secondary outcome was the pre-postinterventional difference in proportion of patients experiencing AWS. Patient demographics and postoperative imaging were assessed. Statistical analyses involved descriptive statistics, a descriptive logistic regression, and a McNemar test.

RESULTS

The results of the study showed that seven (29%) of the 24 patients experienced AWS either previously or during interventional stimulation. However, there was no significant correlation found between AWS and the location of the neurostimulator tip or conus medullaris, and there was no difference in the pre-postinterventional proportion of patients experiencing AWS.

CONCLUSIONS

The study concludes that a relatively high proportion of patients who received SCS for PSPS type 2 experienced or previously experienced AWS. There was no significant correlation found between the location of the neurostimulator tip and the occurrence of AWS. This suggests that AWS may not be solely dependent on the stimulation itself and emphasizes the need to consider other factors. Nonetheless, this study provides important insights into the occurrence of AWS in patients receiving SCS for PSPS type 2 and highlights the need for further research in this area.

CLINICAL TRIAL REGISTRATION

The Clinicaltrials.gov registration number for the study is NCT05565469.

Dorsal root ganglion stimulation for the treatment of chronic pelvic pain: A systematic review

BACKGROUND

Chronic pelvic pain (CPP) is a difficult condition to treat. Due to complex pelvic innervation, dorsal column spinal cord stimulation (SCS) has not been shown to produce the same effect as dorsal root ganglion stimulation (DRGS) given emerging evidence suggesting that applying DRGS may result in favorable outcomes for individuals with CPP. The aim of this systematic review is to investigate the clinical use and effectiveness of DRGS for patients with CPP.

MATERIALS AND METHODS

A systematic review of clinical studies demonstrating the use of DRGS for CPP. Searches were conducted using four electronic databases (PubMed, EMBASE, CINAHL, and Web of Science) across August and September 2022.

RESULTS

A total of nine studies comprising 65 total patients with variable pelvic pain etiologies met the inclusion criteria. The majority of subjects implanted with DRGS reported >50% mean pain reduction at variable times of follow-up. Secondary outcomes reported throughout studies including quality of life (QOL) and pain medication consumption were reported to be significantly improved.

CONCLUSIONS

Dorsal root ganglion stimulation for CPP continues to lack supportive evidence from well-designed, high-quality studies and recommendations from consensus committee experts. However, we present consistent evidence from level IV studies showing success with the use of DRGS for CPP in reducing pain symptoms along with reports of improved QOL through periods as short as 2 months to as long as 3 years. Because the available studies at this time are of low quality with a high risk of bias, we strongly recommend the facilitation of high-quality studies with larger sample sizes in order to better ascertain the utility of DRGS for this specific patient population. At the same time, from a clinical perspective, it may be reasonable and appropriate to evaluate patients for DRGS candidacy on a case-by-case basis, especially those patients who report CPP symptoms that are refractory to noninterventional measures and who may not be ideal candidates for other forms of neuromodulation.

Chronic pain after spine surgery: Insights into pathogenesis, new treatment, and preventive therapy

Chronic pain after spine surgery (CPSS) is often characterized by intractable low back pain and/or radiating leg pain, and has been reported in 8-40% of patients that received lumbar spine surgery. We conducted a literature search of PubMed, MEDLINE/OVID with a focus on studies about the etiology and treatments of CPSS and low back pain. Our aim was to provide a narrative review that would help us better understand the pathogenesis and current treatment options for CPSS. This knowledge will aid in the development of optimal strategies for managing postoperative pain symptoms and potentially curing the underlying etiologies. Firstly, we reviewed recent advances in the mechanistic study of CPSS, illustrated both structural (e.g., fibrosis and scaring) and non-structural factors (e.g., inflammation, neuronal sensitization, glial activation, psychological factor) causing CPSS, and highlighted those having not been given sufficient attention as the etiology of CPSS. Secondly, we summarized clinical evidence and therapeutic perspectives of CPSS. We also presented new insights about the treatments and etiology of CPSS, in order to raise awareness of medical staff in the identification and management of this complex painful disease. Finally, we discussed potential new targets for clinical interventions of CPSS and future perspectives of mechanistic and translational research. CPSS patients often have a mixed etiology. By reviewing recent findings, the authors advocate that clinicians shall comprehensively evaluate each case to formulate a patient-specific and multi-modal pain treatment, and importantly, consider an early intraoperative intervention that may decrease the risk or even prevent the onset of CPSS.

Translational potential statement

CPSS remains difficult to treat. This review broadens our understanding of clinical therapies and underlying mechanisms of CPSS, and provides new insights which will aid in the development of novel mechanism-based therapies for not only managing the established pain symptoms but also preventing the development of CPSS.

Spinal Cord Stimulation Efficacy and Erroneous Conclusions of the Cochrane Library Review of Spinal Cord Stimulation for Low Back Pain by Traeger et al

Neuromodulation, through the use of spinal cord stimulation, is an evolving therapeutic alternative for the management of chronic and refractory pain [...].

Core patient-reported outcome measures for chronic pain patients treated with spinal cord stimulation or dorsal root ganglia stimulation

BACKGROUND

Neurostimulation is a highly effective therapy for the treatment of chronic Intractable pain, however, due to the complexity of pain, measuring a subject's long-term response to the therapy remains difficult. Frequent measurement of patient-reported outcomes (PROs) to reflect multiple aspects of subjects' pain is a crucial step in determining therapy outcomes. However, collecting full-length PROs is burdensome for both patients and clinicians. The objective of this work is to identify the reduced set of questions from multiple validated PROs that can accurately characterize chronic pain patients' responses to neurostimulation therapies.

METHODS

Validated PROs were used to capture pain, physical function and disability, as well as psychometric, satisfaction, and global health metrics. PROs were collected from 509 patients implanted with Spinal Cord Stimulation (SCS) or Dorsal Root Ganglia (DRG) neurostimulators enrolled in the prospective, international, post-market REALITY study (NCT03876054, Registration Date: March 15, 2019). A combination of linear regression, Pearson's correlation, and factor analysis were used to eliminate highly correlated questions and find the minimal meaningful set of questions within the predefined domains of each scale.

RESULTS

The shortened versions of the questionnaires presented almost identical accuracy for classifying the therapy outcomes as compared to the validated full-length versions. In addition, principal component analysis was performed on all the PROs and showed a robust clustering of pain intensity, psychological factors, physical function, and sleep across multiple PROs. A selected set of questions captured from multiple PROs can provide adequate information for measuring neurostimulation therapy outcomes.

CONCLUSIONS

PROs are important subjective measures to evaluate the physiological and psychological aspects of pain. However, these measures are cumbersome to collect. These shorter and more targeted PROs could result in better patient engagement, and enhanced and more frequent data collection processes for digital health platforms that minimize patient burden while increasing therapeutic benefits for chronic pain patients.

Research objectives and general considerations for pragmatic clinical trials of pain treatments: IMMPACT statement

ABSTRACT

Many questions regarding the clinical management of people experiencing pain and related health policy decision-making may best be answered by pragmatic controlled trials. To generate clinically relevant and widely applicable findings, such trials aim to reproduce elements of routine clinical care or are embedded within clinical workflows. In contrast with traditional efficacy trials, pragmatic trials are intended to address a broader set of external validity questions critical for stakeholders (clinicians, healthcare leaders, policymakers, insurers, and patients) in considering the adoption and use of evidence-based treatments in daily clinical care. This article summarizes methodological considerations for pragmatic trials, mainly concerning methods of fundamental importance to the internal validity of trials. The relationship between these methods and common pragmatic trials methods and goals is considered, recognizing that the resulting trial designs are highly dependent on the specific research question under investigation. The basis of this statement was an Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) systematic review of methods and a consensus meeting. The meeting was organized by the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership. The consensus process was informed by expert presentations, panel and consensus discussions, and a preparatory systematic review. In the context of pragmatic trials of pain treatments, we present fundamental considerations for the planning phase of pragmatic trials, including the specification of trial objectives, the selection of adequate designs, and methods to enhance internal validity while maintaining the ability to answer pragmatic research questions.

Evidence-based consensus guidelines on patient selection and trial stimulation for spinal cord stimulation therapy for chronic non-cancer pain

Spinal cord stimulation (SCS) has demonstrated effectiveness for neuropathic pain. Unfortunately, some patients report inadequate long-term pain relief. Patient selection is emphasized for this therapy; however, the prognostic capabilities and deployment strategies of existing selection techniques, including an SCS trial, have been questioned. After approval by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine, a steering committee was formed to develop evidence-based guidelines for patient selection and the role of an SCS trial. Representatives of professional organizations with clinical expertize were invited to participate as committee members. A comprehensive literature review was carried out by the steering committee, and the results organized into narrative reports, which were circulated to all the committee members. Individual statements and recommendations within each of seven sections were formulated by the steering committee and circulated to members for voting. We used a modified Delphi method wherein drafts were circulated to each member in a blinded fashion for voting. Comments were incorporated in the subsequent revisions, which were recirculated for voting to achieve consensus. Seven sections with a total of 39 recommendations were approved with 100% consensus from all the members. Sections included definitions and terminology of SCS trial; benefits of SCS trial; screening for psychosocial characteristics; patient perceptions on SCS therapy and the use of trial; other patient predictors of SCS therapy; conduct of SCS trials; and evaluation of SCS trials including minimum criteria for success. Recommendations included that SCS trial should be performed before a definitive SCS implant except in anginal pain (grade B). All patients must be screened with an objective validated instrument for psychosocial factors, and this must include depression (grade B). Despite some limitations, a trial helps patient selection and provides patients with an opportunity to experience the therapy. These recommendations are expected to guide practicing physicians and other stakeholders and should not be mistaken as practice standards. Physicians should continue to make their best judgment based on individual patient considerations and preferences.

Physical functioning following spinal cord stimulation: a systematic review and meta-analysis

BACKGROUND

Spinal cord stimulation (SCS) has emerged as an important treatment for chronic pain disorders. While there is evidence supporting improvement in pain intensity with SCS therapy, efforts to synthesize the evidence on physical functioning are lacking.

OBJECTIVE

The primary objective of this meta-analysis was to assess long-term physical function following 12 months of SCS for chronic back pain.

EVIDENCE REVIEW

PubMed, EMBASE, Scopus, and CENTRAL databases were searched for original peer-reviewed publications investigating physical function following SCS. The primary outcome was physical function at 12 months following SCS therapy for chronic back pain compared with baseline. A random effects model with an inverse variable method was used. The Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) framework was used to determine the certainty of evidence.

FINDINGS

A total of 518 studies were screened, of which 36 were included. Twenty-two studies were pooled in the meta-analysis. There was a significant reduction in Oswestry Disability Index (ODI) scores at all time frames up to 24 months following implantation. Pooled results revealed significant improvement in ODI scores at 12 months with a mean difference of -17.00% (95% CI -23.07 to -10.94, p<0.001). There was a very low certainty of evidence in this finding as per the GRADE framework. There was no significant difference in subgroup analyses based on study design (randomised controlled trials (RCTs) vs non-RCTs), study funding, or stimulation type.

CONCLUSION

This meta-analysis highlights significant improvements in physical function after SCS therapy. However, this finding was limited by a very low GRADE certainty of evidence and high heterogeneity.

Comparison of clinical outcomes associated with spinal cord stimulation (SCS) or conventional medical management (CMM) for chronic pain: a systematic review and meta-analysis

OBJECTIVE

This study aims to evaluate the efficacy and safety of spinal cord stimulation (SCS) compared to conventional medical management (CMM) for patients diagnosed with chronic pain. Furthermore, the study seeks to compare the utilization of analgesics, as well as the long-term outcomes in terms of quality of life and functional capacity.

DATA SOURCES

We systematically searched Cochrane Library, Web of Science, PubMed, and EMBASE for randomized controlled trials from inception up to February 2022.

REVIEW METHODS

Inclusion and exclusion criteria were set according to the PICOS criteria. We searched for studies in which SCS was compared with CMM alone for chronic pain. Two reviewers independently identified eligible studies and extracted data. Risk of bias assessments were performed according to Cochrane review criteria and Interventional Pain Management Techniques-quality Appraisal of Reliability and Risk of Bias Assessment (IPM-QRB) criteria.

RESULTS

The present meta-analysis comprised eight studies and included a total of 893 patients. Our findings demonstrate that spinal cord stimulation (SCS) in combination with conventional medical management (CMM) is associated with a significant reduction in visual analogue scale (VAS) pain intensity (P = 0.0005) and decreased scores on the McGill Pain Questionnaire (MPQ) (P < 0.0001). Moreover, SCS plus CMM was found to improve patients' quality of life, as evidenced by improvements in SF-36 scores (P < 0.00001), EQ-5D utility index (P = 0.008), and Oswestry Disability Index (ODI) (P < 0.00001). Based on the results of four high-quality randomized controlled trials (RCTs), the level of evidence supporting the efficacy of SCS for the treatment of painful neuropathy is graded as level I to II. In contrast, there is currently only low-level evidence to support the use of high-frequency stimulation and other chronic pain conditions, which can be attributed to a lack of sufficient randomized controlled trials.

LIMITATIONS

The principal limitation of our study is the significant heterogeneity observed among the cohorts investigated. The primary source of this heterogeneity is the fact that spinal cord stimulation is indicated for the treatment of multiple chronic pain conditions. Moreover, variations in the stimulation parameters, differences among manufacturers, and the specific surgical implantation settings contribute to the increased heterogeneity observed in our analyses. To address this issue, we conducted a subgroup analysis based on specific situations and performed evidence synthesis to mitigate the potential impact of heterogeneity. These approaches allow for a more precise interpretation of the results and a more accurate evaluation of the quality of the included studies.

CONCLUSIONS

SCS is an effective treatment to relieve the pain level of chronic pain, decrease analgesic usage, and increase long-term quality of life and functional capacity.

Nonsurgical Interventional Spine Pain Procedures: Outcomes and Complications

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Nonsurgical interventional spine pain procedures provide an additional treatment option for lower back pain at the traditional bifurcation of conversative vs. operative management.

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Transforaminal epidural steroid injections, radiofrequency ablations, intrathecal drug delivery, and spinal cord stimulation were found to be effective and safe techniques when applied to their specific indication.

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Thermal annuloplasty and minimally invasive lumbar decompression showed mixed support.

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Discography, sacroiliac joint injections, and spinous process spacers lacked sufficient evidence to support efficacy.

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Medial branch blocks and facet joint injections were found to be useful diagnostic tools.

Role of patient selection and trial stimulation for spinal cord stimulation therapy for chronic non-cancer pain: a comprehensive narrative review

Background/importance

Patient selection for spinal cord stimulation (SCS) therapy is crucial and is traditionally performed with clinical selection followed by a screening trial. The factors influencing patient selection and the importance of trialing have not been systematically evaluated.

Objective

We report a narrative review conducted to synthesize evidence regarding patient selection and the role of SCS trials.

Evidence review

Medline, EMBASE and Cochrane databases were searched for reports (any design) of SCS in adult patients, from their inception until March 30, 2022. Study selection and data extraction were carried out using DistillerSR. Data were organized into tables and narrative summaries, categorized by study design. Importance of patient variables and trialing was considered by looking at their influence on the long-term therapy success.

Findings

Among 7321 citations, 201 reports consisting of 60 systematic reviews, 36 randomized controlled trials (RCTs), 41 observational studies (OSs), 51 registry-based reports, and 13 case reports on complications during trialing were included. Based on RCTs and OSs, the median trial success rate was 72% and 82%, and therapy success was 65% and 61% at 12 months, respectively. Although several psychological and non-psychological determinants have been investigated, studies do not report a consistent approach to patient selection. Among psychological factors, untreated depression was associated with poor long-term outcomes, but the effect of others was inconsistent. Most RCTs except for chronic angina involved trialing and only one RCT compared patient selection with or without trial. The median (range) trial duration was 10 (0–30) and 7 (0–56) days among RCTs and OSs, respectively.

Conclusions

Due to lack of a consistent approach to identify responders for SCS therapy, trialing complements patient selection to exclude patients who do not find the therapy helpful and/or intolerant of the SCS system. However, more rigorous and large studies are necessary to better evaluate its role.

Spinal cord stimulation for low back pain

BACKGROUND

Spinal cord stimulation (SCS) is a surgical intervention used to treat persistent low back pain. SCS is thought to modulate pain by sending electrical signals via implanted electrodes into the spinal cord. The long term benefits and harms of SCS for people with low back pain are uncertain.

OBJECTIVES

To assess the effects, including benefits and harms, of SCS for people with low back pain.

SEARCH METHODS

On 10 June 2022, we searched CENTRAL, MEDLINE, Embase, and one other database for published trials. We also searched three clinical trials registers for ongoing trials.

SELECTION CRITERIA

We included all randomised controlled trials and cross-over trials comparing SCS with placebo or no treatment for low back pain. The primary comparison was SCS versus placebo, at the longest time point measured in the trials. Major outcomes were mean low back pain intensity, function, health-related quality of life, global assessment of efficacy, withdrawals due to adverse events, adverse events, and serious adverse events. Our primary time point was long-term follow-up (≥ 12 months).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 13 studies with 699 participants: 55% of participants were female; mean age ranged from 47 to 59 years; and all participants had chronic low back pain with mean duration of symptoms ranging from five to 12 years. Ten cross-over trials compared SCS with placebo. Three parallel-group trials assessed the addition of SCS to medical management. Most studies were at risk of performance and detection bias from inadequate blinding and selective reporting bias. The placebo-controlled trials had other important biases, including lack of accounting for period and carryover effects. Two of the three parallel trials assessing SCS as an addition to medical management were at risk of attrition bias, and all three had substantial cross-over to the SCS group for time points beyond six months. In the parallel-group trials, we considered the lack of placebo control to be an important source of bias. None of our included studies evaluated the impact of SCS on mean low back pain intensity in the long term (≥ 12 months). The studies most often assessed outcomes in the immediate term (less than one month). At six months, the only available evidence was from a single cross-over trial (50 participants). There was moderate-certainty evidence that SCS probably does not improve back or leg pain, function, or quality of life compared with placebo. Pain was 61 points (on a 0- to 100-point scale, 0 = no pain) at six months with placebo, and 4 points better (8.2 points better to 0.2 points worse) with SCS. Function was 35.4 points (on a 0- to 100-point scale, 0 = no disability or best function) at six months with placebo, and 1.3 points better (3.9 points better to 1.3 points worse) with SCS. Health-related quality of life was 0.44 points out of 1 (0 to 1 index, 0 = worst quality of life) at six months with placebo, and 0.04 points better (0.16 points better to 0.08 points worse) with SCS. In that same study, nine participants (18%) experienced adverse events and four (8%) required revision surgery. Serious adverse events with SCS included infections, neurological damage, and lead migration requiring repeated surgery. We could not provide effect estimates of the relative risks as events were not reported for the placebo period. In parallel trials assessing SCS as an addition to medical management, it is uncertain whether, in the medium or long term, SCS can reduce low back pain, leg pain, or health-related quality of life, or if it increases the number of people reporting a 50% improvement or better, because the certainty of the evidence was very low. Low-certainty evidence suggests that adding SCS to medical management may slightly improve function and slightly reduce opioid use. In the medium term, mean function (0- to 100-point scale; lower is better) was 16.2 points better with the addition of SCS to medical management compared with medical management alone (95% confidence interval (CI) 19.4 points better to 13.0 points better; I2 = 95%; 3 studies, 430 participants; low-certainty evidence). The number of participants reporting opioid medicine use was 15% lower with the addition of SCS to medical management (95% CI 27% lower to 0% lower; I2 = 0%; 2 studies, 290 participants; low-certainty evidence). Adverse events with SCS were poorly reported but included infection and lead migration. One study found that, at 24 months, 13 of 42 people (31%) receiving SCS required revision surgery. It is uncertain to what extent the addition of SCS to medical management increases the risk of withdrawals due to adverse events, adverse events, or serious adverse events, because the certainty of the evidence was very low.

AUTHORS' CONCLUSIONS

Data in this review do not support the use of SCS to manage low back pain outside a clinical trial. Current evidence suggests SCS probably does not have sustained clinical benefits that would outweigh the costs and risks of this surgical intervention.

Combination therapy with simultaneous delivery of spinal cord stimulation modalities: COMBO randomized controlled trial

Aim: The Combining Mechanisms for Better Outcomes randomized controlled trial assessed the effectiveness of various spinal cord stimulation (SCS) modalities for chronic pain. Specifically, combination therapy (simultaneous use of customized sub-perception field and paresthesia-based SCS) versus monotherapy (paresthesia-based SCS) was evaluated. Methods: Participants were prospectively enrolled (key inclusion criterion: chronic pain for ≥6 months). Primary end point was the proportion with ≥50% pain reduction without increased opioids at the 3-month follow-up. Patients were followed for 2 years. Results: The primary end point was met (n = 89; p < 0.0001) in 88% of patients in the combination-therapy arm (n = 36/41) and 71% in the monotherapy arm (n = 34/48). Responder rates at 1 and 2 years (with available SCS modalities) were 84% and 85%, respectively. Sustained functional outcomes improvement was observed out to 2 years. Conclusion: SCS-based combination therapy can improve outcomes in patients with chronic pain. Clinical Trial Registration: NCT03689920 (ClinicalTrials.gov), Combining Mechanisms for Better Outcomes (COMBO).

A comprehensive review of emodin in fibrosis treatment

Emodin is the main pharmacodynamic components of rhubarb, with significant pharmacological effects and clinical efficacy.Emodin has a variety of therapy effects, such as anti-cancer, anti-fibrosis effects, and is widely used to treat encephalitis, diabetic cataract and organ fibrosis. Several studies have shown that emodin has a good treatment effect on organ fibrosis, but the mechanism is complex. Moreover, the evidence of some studies is conflicting and confusing. This paper reviewed the mechanism, pharmacokinetics and toxicology of emodin in fibrosis treatment, and briefly discussed relevant cutting-edge new formulations to improve the efficacy, the result can provide some reference for future study.

"Neuro-Fiber Mapping": An Original Concept of Spinal Cord Neural Network Spatial Targeting Using Live Electrostimulation Mapping to (Re-)Explore the Conus Medullaris Anatomy

Spinal cord (SC) anatomy is often assimilated to a morphologically encapsulated neural entity, but its functional anatomy remains only partially understood. We hypothesized that it could be possible to re-explore SC neural networks by performing live electrostimulation mapping, based on "super-selective" spinal cord stimulation (SCS), originally designed as a therapeutical tool to address chronic refractory pain. As a starting point, we initiated a systematic SCS lead programming approach using live electrostimulation mapping on a chronic refractory perineal pain patient, previously implanted with multicolumn SCS at the level of the conus medullaris (T12-L1). It appeared possible to (re-)explore the classical anatomy of the conus medullaris using statistical correlations of paresthesia coverage mappings, resulting from 165 different electrical configurations tested. We highlighted that sacral dermatomes were not only located more medially but also deeper than lumbar dermatomes at the level of the conus medullaris, in contrast with classical anatomical descriptions of SC somatotopical organization. As we were finally able to find a morphofunctional description of "Philippe-Gombault's triangle" in 19th-century historical textbooks of neuroanatomy, remarkably matching these conclusions, the concept of "neuro-fiber mapping" was introduced.

Proportion of clinical holistic responders in patients with persistent spinal pain syndrome type II treated by subthreshold spinal cord stimulation compared to best medical treatment: a study protocol for a multicentric randomised controlled trial (TRADITION)

BACKGROUND

Integrating information on bodily functions, pain intensity and quality of life into one composite measure of a holistic responder has recently been proposed as a useful method to evaluate treatment efficacy of spinal cord stimulation (SCS) in patients with therapy-refractory persistent spinal pain syndrome type II (PSPS-T2). Previous studies already demonstrated the efficacy of standard SCS over best medical treatment (BMT) and the superiority of new subthreshold (i.e. paresthesia free) SCS paradigms compared to standard SCS. Nevertheless, the efficacy of subthreshold SCS compared to BMT has not yet been investigated in patients with PSPS-T2, neither with unidimensional outcomes nor with a composite measure. The current objective is to examine whether subthreshold SCS, compared to BMT, provided to patients with PSPS-T2 results in a different proportion of clinical holistic responders (as composite measure) at 6 months.

METHODS

A two-arm multicentre randomised controlled trial will be conducted whereby 114 patients will be randomised (1:1) to (a) BMT or (b) paresthesia-free SCS. After a follow-up period of 6 months (primary time endpoint), patients receive the opportunity to cross over towards the other treatment group. The primary outcome is the proportion of clinical holistic responders at 6 months (i.e. a composite measure of pain intensity, medication, disability, health-related quality of life and patient satisfaction). The secondary outcomes are work status, self-management, anxiety, depression and healthcare expenditure.

DISCUSSION

Within the TRADITION project, we propose to shift the focus from a unidimensional outcome measure towards a composite measure as primary outcome measure to evaluate the efficacy of currently used subthreshold SCS paradigms. The lack of methodologically rigorous trials exploring the clinical efficacy and socio-economic consequences of subthreshold SCS paradigms is pressing, especially in light of the growing burden of PSPS-T2 on the society.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05169047. Registered on December 23, 2021.

Long-term safety of spinal cord stimulation systems in a prospective, global registry of patients with chronic pain

Aim: The availability of long-term (>2 years) safety outcomes of spinal cord stimulation (SCS) remains limited. We evaluated safety in a global SCS registry for chronic pain. Methods: Participants were prospectively enrolled globally at 79 implanting centers and followed out to 3 years after device implantation. Results: Of 1881 participants enrolled, 1289 received a permanent SCS implant (1776 completed trial). The annualized rate of device explant was 3.5% (all causes), and 1.1% due to inadequate pain relief. Total incidence of device explantation >3 years was 7.6% (n = 98). Of these, 32 subjects (2.5%) indicated inadequate pain relief as cause for removal. Implant site infection (11 events) was the most common device-related serious adverse event (<1%). Conclusion: This prospective, global, real-world study demonstrates a high-level of safety for SCS with low rate of explant/serious adverse events. Clinical Trial Registration: NCT01719055 (ClinicalTrials.gov).

Spinal cord stimulation and return to work of patients with failed back surgery syndrome

OBJECTIVES

Chronic pain has a substantial negative impact on work-related outcomes, which underlines the importance of interventions to reduce the burden. Spinal cord stimulation (SCS) efficiently relieves pain in specific chronic pain syndromes and is recommended for treating failed back surgery syndrome (FBSS) or post-surgical chronic back pain that is refractory to other treatments. To examine the impact of SCS in patients with FBSS on the return to work (RTW), we determined the RTW rate and the factors positively associated with the RTW.

MATERIALS AND METHODS

Among 106 patients with FBSS who benefitted from SCS at a single institution in France between September 1999 and March 2010, we retrospectively included 59 who had stopped work at the time of SCS because of disability or sick leave and evaluated the RTW (rate and predictors, estimating odds ratios [ORs] and 95% confidence intervals [CIs]).

RESULTS

The mean (SD) post-surgery follow-up for the 59 patients (34 men; mean [SD] age 46.9 [7.4] years) was 7.5 (3.6) years (range 5-15). The RTW rate was 30.5%, with a median [IQR] recovery time of 5.5 months [3-8.5]. RTW was improved with functional improvement evolution (OR 1.1, 95% CI [1.01-1.1], p = 0.02) and was reduced with unemployment > 3 years (OR 0.1, 95% CI [0.01-0.7], p = 0.02).

CONCLUSIONS

Our protocol for SCS for patients with FBSS, including a strict selection of patients and a multidisciplinary approach, led to good results, especially for the RTW. RTW should be a therapeutic goal, directly affecting indirect costs related to FBSS.

Efficacy of Spinal Cord Stimulation for Failed Back Surgery Syndrome in Elderly Patients: A Retrospective Study

Objectives

Failed back surgery syndrome (FBSS) refers to a condition where symptoms such as low back pain, leg pain, and numbness persist or recur after lumbar surgery; it has been reported to occur in 10%-40% of patients who have undergone lumbar surgery. Spinal cord stimulation (SCS) has been reported useful for low back and leg pain due to FBSS. In this study, we studied the efficacy and safety of SCS for FBSS in older adults.

Methods

Among FBSS patients who underwent an SCS trial between November 2017 and December 2020, those with at least 50% pain reduction during the trial phase who requested spinal cord stimulator implantation underwent implantation of a stimulator under local anesthesia. The patients were divided into two groups: patients aged <75 years (<75-year-old group) and patients aged ≥75 years (≥75-year-old group). The male/female ratio, symptom duration, operative duration, visual analog scale (VAS) scores before and after one year of surgery, responder rate (RR), complications one year after surgery, and stimulator removal rate were analyzed.

Results

There were 27 cases in the <75-year-old group and 46 in the ≥75-year-old group, with no significant differences in male/female ratio, duration of pain, or operative time between the two groups. VAS scores for low back pain, leg pain, and overall pain one year after surgery were improved significantly from respective preoperative scores in both groups (P < 0.001). There were no significant differences in low back pain VAS, leg pain VAS, overall pain VAS, RR, complications one year after surgery, or stimulator removal rate between the two groups.

Conclusion

SCS reduced pain effectively in both <75-year-old and ≥75-year-old groups with no differences in complications. Therefore, spinal cord stimulator implantation was considered a viable option for FBSS treatment in older adults because it can be performed under local anesthesia and is associated with a low incidence of complications.

Spinal Cord Stimulation-Naïve Patients vs Patients With Failed Previous Experiences With Standard Spinal Cord Stimulation: Two Distinct Entities or One Population?

INTRODUCTION

Nowadays, the success of spinal cord stimulation (SCS) is evaluated separately in patients who have previous experiences with standard SCS and in SCS-naïve patients. Nevertheless, it is yet to be evaluated whether both patient groups are effectively distinct patient groups. Therefore, the aims of this study are twofold: 1) Are there clusters in the data to distinguish between both patient groups? 2) Can we discriminate both patient groups based on routinely collected clinical parameters?

MATERIALS AND METHODS

Baseline data from the Discover study were used, in which 263 patients with persistent spinal pain syndrome type 2 were included (185 neurostimulation-naïve patients and 78 patients with previous SCS experience). Pain intensity scores for low back and leg pain, functional disability, medication use, and health-related quality of life utility scores were used in the analysis. Model-based clustering was performed on standardized data. Discriminant analysis was performed with linear and quadratic discriminant analysis, with leave-one-out cross-validation to evaluate model performance.

RESULTS

Model-based clustering revealed two different clusters in the data. None of the clusters clearly separated SCS-naïve patients from patients with previous SCS experience. Linear discriminant analysis resulted in a leave-one-out cross-validation error rate of 30.0% to discriminate between both patient groups, based on routinely collected clinical parameters.

CONCLUSIONS

Clustering analysis did not result in clusters that separate SCS-naïve patients from patients with previous SCS experience. This may suggest that both patient groups should not be considered as two different patient groups when comparing them on routine clinical parameters, with potentially profound implications for research and clinical settings.

CLINICAL TRIAL REGISTRATION

The Clinicaltrials.gov registration number for the Discover study is NCT02787265.

Long term outcomes of occipital nerve stimulation

Background

Occipital nerve stimulation (ONS) has been investigated as a potential treatment for disabling headaches and has shown promise for disorders such as chronic migraine and cluster headache. Long term outcomes stratified by headache subtype have had limited exploration, and literature on outcomes of this neuromodulatory intervention spanning 2 or more years is scarce.

Measures

We performed a narrative review on long term outcomes with ONS for treatment of headache disorders. We surveyed the available literature for studies that have outcomes for 24 months or greater to see if there is a habituation in response over time. Review of the literature revealed evidence in treatment of occipital neuralgia, chronic migraine, cluster headache, cervicogenic headache, short lasting unilateral neuralgiform headache attacks (SUNHA) and paroxysmal hemicrania. While the term "response" varied per individual study, a total of 17 studies showed outcomes in ONS with long term sustained responses (as defined per this review) in the majority of patients with specific headache types 177/311 (56%). Only 7 studies in total (3 cluster, 1 occipital neuralgia, 1 cervicogenic headache, 1 SUNHA, 1 paroxysmal hemicrania) provided both short-term and long-term responses up to 24 months to ONS. In cluster headache, the majority of patients (64%) were long term responders (as defined per this review) and only a minority of patients 12/62 (19%) had loss of efficacy (e.g., habituation). There was a high number 313/439 (71%) of adverse events per total number of patients in the studies including lead migration, requirements of revision surgery, allergy to surgical materials, infection and intolerable paresthesias.

Conclusions

With the evidence available, the response to ONS was sustained in the majority of patients with cluster headache with low rates of loss of efficacy in this patient population. There was a high percent of adverse events per number of patients in long term follow-up and likely related to the off-label use of leads typically used for spinal cord stimulation. Further longitudinal assessments of outcomes in occipital nerve stimulation with devices labelled for use in peripheral nerve stimulation are needed to evaluate the extent of habituation to treatment in headache.