Sonication in Patients With Spinal Cord Stimulation: A New Approach for Infection Diagnostics

INTRODUCTION

Spinal cord stimulation (SCS) offers improvement in pain and function for several chronic pain conditions. There are concerns regarding bacterial colonization of the temporary lead extensions and subsequent infection risk in a two-session implantation procedure. Although there is no standardized evaluation of SCS lead contamination, this study evaluates the infection rate and microbial colonization of SCS lead extensions with sonication, a method that is established in implant-related infection diagnostics.

MATERIALS AND METHODS

This prospective observational study comprised 32 patients with a two-stage SCS implantation procedure. Microbial colonization of the lead extensions was assessed with sonication. The presence of organisms in the subcutaneous tissue was evaluated separately. Surgical-site infections were recorded. Patient demographics and risk factors including diabetes, tobacco use, obesity, trial length, and infection parameters in serum were recorded and analyzed.

RESULTS

The mean age of the patients was 55 years. On average, the trial length was 13 days. In seven cases (21.9%), a microbial lead colonization was found with sonication. In contrast, there was one positive culture (3.1%) from the subcutaneous tissue samples. The C-reactive protein and leukocyte count remained at the preoperative level. One early surgical-site infection (3.1%) occurred. No other late infections occurred six months after surgery.

CONCLUSIONS

There is a discrepancy between the presence of microbial colonization and the occurrence of clinically relevant infections. Although the rate of microbial colonization of the lead extensions is high (21.9%), the surgical-site infection rate remained low (3.1%). Therefore, we can conclude that the two-session procedure is a safe approach that is not associated with a higher incidence of infection. Although the sonication method cannot be used as the sole tool for detecting infections in patients with SCS, it can provide additional value in microbial diagnostics in combination with clinical and laboratory parameters and conventional microbiological methods.

Healthcare Economics of High Frequency Spinal Cord Stimulation for Painful Diabetic Peripheral Neuropathy

BACKGROUND

Painful diabetic peripheral neuropathy (pDPN) is a debilitating complication of long-term diabetes. High-frequency spinal cord stimulation (HF-SCS) was recently shown to be an effective treatment option, but the associated healthcare resource utilization (HCRU) on real-world patient populations with pDPN is unknown.

METHODS

Using IBM MarketScan databases, we identified patients with HF-SCS implantation between January 2016 and December 2019 who had a diagnosis of diabetes or diabetic neuropathy within two years before implant. Cost data were collected for the six months before HF-SCS implantation (baseline) and for the periods of one, three, and six months post-implantation. The six-month explant rate was calculated.

RESULTS

A total of 132 patients met inclusion criteria. The median total cost at baseline was $19 220 and was $1356 at one month post-implant, $4858 at three months post-implant, and $13 305 at six months post-implant. The median baseline out-of-pocket cost was $1477 and was $710 at six months post-implant. The average total cost reduction from baseline to six months post-implant was $5118 (P < .001), or $853 per month. The median device acquisition cost was $35 755. The explant rate within six months was 2.1%.

CONCLUSIONS

High frequency spinal cord stimulation significantly reduces total HCRU in patients with pDPN, and based on the average monthly cost reduction of $853, we estimate that the therapy recoups acquisition costs within 3.5 years. As policy increasingly focuses on value-based care, it will be critical to consider the cost and outcomes of innovative therapies.

Healthcare Utilization (HCU) Reduction with High-Frequency (10 kHz) Spinal Cord Stimulation (SCS) Therapy

Spinal cord stimulation (SCS) is a well-established treatment for patients with chronic pain. With increasing healthcare costs, it is important to determine the benefits of SCS in healthcare utilization (HCU). This retrospective, single-center observational study involved 160 subjects who underwent implantation of a high-frequency (10 kHz) SCS device. We focused on assessing trends in HCU by measuring opioid consumption in morphine milligram equivalents (MME), as well as monitoring emergency department (ED) and office visits for interventional pain procedures during the 12-month period preceding and following the SCS implant. Our results revealed a statistically significant reduction in HCU in all domains assessed. The mean MME was 51.05 and 26.52 pre- and post-implant, respectively. There was a 24.53 MME overall decrease and a mean of 78.2% statistically significant dose reduction (p < 0.0001). Of these, 91.5% reached a minimally clinically important difference (MCID) in opioid reduction. Similarly, we found a statistically significant (p < 0.01) decrease in ED visits, with a mean of 0.12 pre- and 0.03 post-implant, and a decrease in office visits for interventional pain procedures from a 1.39 pre- to 0.28 post-10 kHz SCS implant, representing a 1.11 statistically significant (p < 0.0001) mean reduction. Our study reports the largest cohort of real-world data published to date analyzing HCU trends with 10 kHz SCS for multiple pain etiologies. Furthermore, this is the first and only study evaluating HCU trends with 10 kHz SCS by assessing opioid use, ED visits, and outpatient visits for interventional pain procedures collectively. Preceding studies have individually investigated these outcomes, consistently yielding positive results comparable to our findings.

Cooled radiofrequency ablation versus standard medical management for chronic sacroiliac joint pain: a multicenter, randomized comparative effectiveness study

INTRODUCTION

Low back pain is the leading cause of disability worldwide, with sacroiliac joint pain comprising up to 30% of cases of axial lower back pain. Conservative therapies provide only modest relief. Although placebo-controlled trials show efficacy for sacral lateral branch cooled radiofrequency ablation, there are no comparative effectiveness studies.

METHODS

In this randomized, multicenter comparative effectiveness study, 210 patients with clinically suspected sacroiliac joint pain who obtained short-term benefit from diagnostic sacroiliac joint injections and prognostic lateral branch blocks were randomly assigned to receive cooled radiofrequency ablation of the L5 dorsal ramus and S1-S3 lateral branches or standard medical management consisting of pharmacotherapy, injections and integrative therapies. The primary outcome measure was mean reduction in low back pain score on a 0-10 Numeric Rating Scale at 3 months. Secondary outcomes included measures of quality of life and function.

RESULTS

3 months post-treatment, the mean Numeric Rating Scale pain score for the cooled radiofrequency ablation group was 3.8±2.4 (mean reduction 2.5±2.5) compared with 5.9±1.7 (mean reduction 0.4±1.7) in the standard medical management group (p<0.0001). 52.3% of subjects in the cooled radiofrequency ablation group experienced >2 points or 30% pain relief and were deemed responders versus 4.3% of standard medical management patients (p<0.0001). Comparable improvements favoring cooled radiofrequency ablation were noted in Oswestry Disability Index score (mean 29.7±15.2 vs 41.5+13.6; p<0.0001) and quality of life (mean EuroQoL-5 score 0.68±0.22 vs 0.47±0.29; p<0.0001).

CONCLUSIONS

In patients with sacroiliac joint pain, cooled radiofrequency ablation provided statistically superior improvements across the spectrum of patient outcomes compared with standard medical management.

TRIAL REGISTRATION NUMBER

NCT03601949.

A single-center real-world review of 10 kHz high-frequency spinal cord stimulation outcomes for treatment of chronic pain

Objective

To compare pragmatic real-world 10-kHz high-frequency spinal cord stimulation (HF-SCS) outcomes at a single academic center to the industry-sponsored SENZA-RCT and Stauss et al. study.

Methods

This single-center retrospective study included patients with refractory back or limb pain trialed and/or permanently implanted with the Nevro HF-SCS system from 2016 to 2021. Demographic and outcome data were obtained from the electronic medical record (EMR) and real-world global database maintained by Nevro Corp. Data obtained from the global database were confirmed using the EMR. Main outcome measures included positive responder status (≥50% patient-reported percentage pain reduction (PRPPR)), improvement in function, improvement in sleep, and reduction in pain medication usage. Comparison groups included patient outcomes from the SENZA-RCT and Stauss et al. study.

Results

Patients (N = 147) trialed with HF-SCS were reviewed, with data available for 137. Positive trialed patient responder rate (≥50% PRPPR) was 77% (106/137, 95CI 70-84%) vs. 87% (1393/1607, 95CI 85-89%) Stauss et al. vs. 93% (90/97, 95CI 88-98%) SENZA-RCT HF-SCS. At the last available follow-up, positive implanted patient responder rate was 73% (58/80, 95CI 63-82%) vs. 78% (254/326, 95CI 73-82%) Stauss et al. vs. 79% (71/90, 95CI 70-87%) SENZA-RCT HF-SCS. Sixty-seven percent (59/88, 95CI 57-77%) reported improved function vs. 72% (787/1088, 95CI 70-75%) Stauss et al.; 45% (31/69, 95CI 33-57%) reported improved sleep vs. 68% (693/1020, 95CI 65-71%) Stauss et al. and 16% (9/56, 95CI 6-26%) reported decrease in medication use vs. 32% (342/1070, 95CI 29-35%) Stauss et al.

Conclusion

Patient responder rates in this retrospective pragmatic real-world study of HF-SCS are consistent with previous industry-sponsored studies. However, improvements in quality-of-life measures and reduction in medication usage were not as robust as reported in industry-sponsored studies. The findings of this non-industry-sponsored, independent study of HF-SCS complement those of previously published studies by reporting patient outcomes collected in the absence of industry sponsorship.

Systematic Review to Identify Predictors of Treatment Response to Neuromodulation in Patients With Neuropathic Pain-Protocol

OBJECTIVES

Patients who suffer from long-term, neuropathic pain that proves refractory to conventional medical management are high consumers of health care resources and experience poorer physical and mental health than people with other forms of pain. Pharmacologic treatments have adverse effects; nonpharmacologic interventions have limitations. Spinal cord stimulation (SCS) is an effective treatment for neuropathic pain, although 30% to 40% of patients fail to achieve acceptable levels of pain relief. There are currently no objective methods to predict the success of SCS to treat neuropathic pain, and therefore, it is important to understand which patient factors may be predictive of a lack of response to SCS, to inform future patient treatment options. This study proposes a protocol for a systematic review and meta-analysis of published studies to examine these predictive factors.

MATERIALS AND METHODS

Several bibliographic databases will be searched to identify relevant studies published since 2012 that provide data on patient characteristics (eg, age, gender, pain severity) as predictors of SCS outcomes of pain, function, and health-related quality of life. Two independent reviewers will screen citations; data will be extracted after full-text screening. Risk of bias will be assessed using the Quality In Prognosis Studies tool.

RESULTS

A formal quantitative synthesis is planned in which data from studies with the same predictive factors are available; this will be considered for pooling into separate meta-analyses. In cases of high heterogeneity or inconsistency in the data, subgroup analysis will be conducted.

CONCLUSIONS

This study seeks to provide a contemporary review of patient predictors of success of neuromodulation for neuropathic pain. We anticipate that findings may guide the use of neuromodulation in patient subgroups and the design and reporting of future clinical studies in this field.

Rates and Causes of Reoperations Following Spinal Cord Stimulation Within a 2-12 year Period

STUDY DESIGN

Retrospective study.

OBJECTIVE

Spinal cord stimulation has been mainly used for the management of postsurgical persistent neuropathic. The purpose of the study was to evaluate the rate and causes for reoperation following spinal cord stimulation, and to identify risk factors for reoperation.

METHODS

A retrospective study was conducted including patients who underwent surgical implantation of spinal cord stimulators within a 10-year period. The medical records of the included patients were reviewed for reoperations, demographics and certain clinical parameters. Demographics and clinical parameters were compared between patients with and without reoperations, and between patients with and without surgical site infections.

RESULTS

Overall, 1014 index procedures and 175 reoperations were performed within the study period. At least 1 reoperation was performed in 97 (9.5%) cases. The most common cause for revision was lead migration or lead misplacement (n = 31, 3.0%). In 31 (3.1%) cases the stimulator was removed due to no pain relief. Surgical site infection that required reoperation developed in 30 cases (2.9%). Younger age was associated with a need for reoperation (Odds Ratio [OR]: .97,95% Confidence Interval [CI]:0.95-.99, P = .005), while higher Body Mass index and diabetes were associated with development of infection (OR: 1.05, 95% CI: 1.00-1.11, P = .036 and OR: 2.42, 95% CI: 1.05-5.47, P = .033 respectively).

CONCLUSIONS

The results of this study indicate that certain measures could improve the overall reoperation rate after spinal cord stimulation, such as accurate positioning of the spinal cord stimulators and design of smaller generators. Moreover, preoperative optimization of patients could result in lower complication rate, lower reoperations rate, and subsequently better clinical outcomes.

Device profile of the Evoke physiologic closed-loop spinal cord stimulation system for the treatment of chronic intractable pain: overview of its safety and efficacy

INTRODUCTION

The Evoke® spinal cord stimulation (SCS) device enables the closed-loop feedback of dynamically measured evoked compound action potentials (ECAPs) to adjust stimulation amplitude for every stimulation pulse to maintain the stimulation output level near a targeted ECAP amplitude. No other commercially available SCS device presently uses physiologic feedback from the spinal cord to adjust stimulation. Clinicians should be familiar with the differences in devices and with the latest technologies to provide optimized patient care.

AREAS COVERED

In this device profile, the Evoke system is described and the system capabilities are differentiated from other available SCS devices. A systematic review was conducted based on best practice guidance to identify all available evidence on the safety and efficacy of the Evoke SCS system.

EXPERT OPINION

The Evoke SCS system offers unique capabilities as a means to optimize therapy delivery tailored to each individual patient. Data through 24-months follow-up show statistically significant, clinically meaningful, ample, consistent, and strong evidence of the safety and efficacy of the Evoke system for the treatment of chronic intractable pain.

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.

Diagnosis and Management of Neuropathic Pain in Spine Diseases

Neuropathic pain is generally defined as a non-physiological pain experience caused by damage to the nervous system. It can occur spontaneously, as a reaction to a given stimulus, or independently of its action, leading to unusual pain sensations usually referred to as firing, burning or throbbing. In the course of spine disorders, pain symptoms commonly occur. According to available epidemiological studies, a neuropathic component of pain is often present in patients with spinal diseases, with a frequency ranging from 36% to 55% of patients. Distinguishing between chronic nociceptive pain and neuropathic pain very often remains a challenge. Consequently, neuropathic pain is often underdiagnosed in patients with spinal diseases. In reference to current guidelines for the treatment of neuropathic pain, gabapentin, serotonin and norepinephrine reuptake inhibitors and tricyclic antidepressants constitute first-line therapeutic agents. However, long-term pharmacologic treatment often leads to developing tolerance and resistance to used medications. Therefore, in recent years, a plethora of therapeutic methods for neuropathic pain have been developed and investigated to improve clinical outcomes. In this review, we briefly summarized current knowledge about the pathophysiology and diagnosis of neuropathic pain. Moreover, we described the most effective treatment approaches for neuropathic pain and discussed their relevance in the treatment of spinal pain.

Long-term Outcomes in Use of Opioids, Nonpharmacologic Pain Interventions, and Total Costs of Spinal Cord Stimulators Compared With Conventional Medical Therapy for Chronic Pain

Importance

Spinal cord stimulators (SCSs) are increasingly used for the treatment of chronic pain. There is a need for studies with long-term follow-up.

Objective

To determine the comparative effectiveness and costs of SCSs compared with conventional medical management (CMM) in a large cohort of patients with chronic pain.

Design, Setting, and Participants

This was a 1:5 propensity-matched retrospective comparative effectiveness research analysis of insured individuals from April 1, 2016, to August 31, 2018. This study used administrative claims data, including longitudinal medical and pharmacy claims, from US commercial and Medicare Advantage enrollees 18 years or older in Optum Labs Data Warehouse. Patients with incident diagnosis codes for failed back surgery syndrome, complex regional pain syndrome, chronic pain syndrome, and other chronic postsurgical back and extremity pain were included in this study. Data were analyzed from February 1, 2021, to August 31, 2022.

Exposures

SCSs or CMM.

Main Outcomes and Measures

Surrogate measures for primary chronic pain treatment modalities, including pharmacologic and nonpharmacologic pain interventions (epidural and facet corticosteroid injections, radiofrequency ablation, and spine surgery), as well as total costs.

Results

In the propensity-matched population of 7560 patients, mean (SD) age was 63.5 (12.5) years, 3080 (40.7%) were male, and 4480 (59.3%) were female. Among matched patients, during the first 12 months, patients treated with SCSs had higher odds of chronic opioid use (adjusted odds ratio [aOR], 1.14; 95% CI, 1.01-1.29) compared with patients treated with CMM but lower odds of epidural and facet corticosteroid injections (aOR, 0.44; 95% CI, 0.39-0.51), radiofrequency ablation (aOR, 0.57; 95% CI, 0.44-0.72), and spine surgery (aOR, 0.72; 95% CI, 0.61-0.85). During months 13 to 24, there was no significant difference in chronic opioid use (aOR, 1.06; 95% CI, 0.94-1.20), epidural and facet corticosteroid injections (aOR, 1.00; 95% CI, 0.87-1.14), radiofrequency ablation (aOR, 0.84; 95% CI, 0.66-1.09), or spine surgery (aOR, 0.91; 95% CI, 0.75-1.09) with SCS use compared with CMM. Overall, 226 of 1260 patients (17.9%) treated with SCS experienced SCS-related complications within 2 years, and 279 of 1260 patients (22.1%) had device revisions and/or removals, which were not always for complications. Total costs of care in the first year were $39 000 higher with SCS than CMM and similar between SCS and CMM in the second year.

Conclusions and Relevance

In this large, real-world, comparative effectiveness research study comparing SCS and CMM for chronic pain, SCS placement was not associated with a reduction in opioid use or nonpharmacologic pain interventions at 2 years. SCS was associated with higher costs, and SCS-related complications were common.

Spinal cord stimulation for treatment of chronic neuropathic pain in adolescent patients: a single-institution series, systematic review, and individual participant data meta-analysis

OBJECTIVE

Neuropathic pain is undertreated in children. Neurosurgical treatments of pediatric chronic pain are limited by the absence of both US Food and Drug Administration approval and pediatric-specific hardware, as well as weak referral patterns due to a lack of physician education. This study presents a single-institution retrospective case series of spinal cord stimulation (SCS) in children ≤ 19 years of age and a systematic review of SCS in children. The authors’ findings may further validate the role of SCS as an effective treatment modality for varied neuropathic pain syndromes found in pediatric patients.

METHODS

The study was a single-center, single-surgeon, retrospective case series of individuals treated between July 2017 and May 2022. The outcomes for pediatric patients with chronic neuropathic pain syndromes indicated by the multidisciplinary pain clinic for evaluation for SCS were cataloged. A systematic review and individual participant data (IPD) meta-analysis was performed for cases treated until May 2022, using PubMed, EMBASE, and Scopus to characterize outcomes of children with neuropathic pain treated with SCS.

RESULTS

Twelve patients were evaluated and 9 were indicated for percutaneous or buried lead trials. Seven female and 2 male patients between the ages of 13 and 19 years were implanted with trial leads. Eight of 9 (89%) patients went on to receive permanent systems. The average trial length was 6 days, and the length of stay for both trial and implant was less than 1 day. Complication rates due to CSF leaks were 22% and 0% for trial and implant, respectively. Visual analog scale pain scores decreased from 9.2 to 2.9 (p = 0.0002) and the number of medications decreased from 4.9 to 2.1 (p = 0.0005). Functional status also improved for each patient. A systematic review identified 13 studies describing pediatric patients with SCS, including 12 providing IPD on 30 patients. In the IPD meta-analysis, pain was reduced in 16/16 (100%) of patients following surgery and in 25/26 (96.2%) at last follow-up. Medication use was decreased in 16/21 (76.2%), and functional outcomes were improved in 29/29 (100%). The complication rate was 5/30 (16.7%).

CONCLUSIONS

SCS effectively decreases pain and medication use for pediatric neuropathic pain syndromes. Patients also report improved functional status, including improved matriculation, gainful employment, and physical activity. There is minimal high-quality literature describing neuromodulation for pain in children. Neuromodulation should be considered earlier as a viable alternative to escalating use of multiple drugs and as a potential mechanism to address tolerance, dependence, and addiction in pediatric patients.

Evidence-Based Clinical Guidelines from the American Society of Pain and Neuroscience for the Use of Implantable Peripheral Nerve Stimulation in the Treatment of Chronic Pain

The objective of this peripheral nerve stimulation consensus guideline is to add to the current family of consensus practice guidelines and incorporate a systematic review process. The published literature was searched from relevant electronic databases, including PubMed, Scopus, Cochrane Central Register of Controlled Trials, and Web of Science from database inception to March 29, 2021. Inclusion criteria encompassed studies that described peripheral nerve stimulation in patients in terms of clinical outcomes for various pain conditions, physiological mechanism of action, surgical technique, technique of placement, and adverse events. Twenty randomized controlled trials and 33 prospective observational studies were included in the systematic review process. There is Level I evidence supporting the efficacy of PNS for treatment of chronic migraine headaches via occipital nerve stimulation; chronic hemiplegic shoulder pain via stimulation of nerves innervating the trapezius, supraspinatus, and deltoid muscles; failed back surgery syndrome via subcutaneous peripheral field stimulation; and lower extremity neuropathic and lower extremity post-amputation pain. Evidence from current Level I studies combined with newer technologies facilitating less invasive and easier electrode placement make peripheral nerve stimulation an attractive alternative for managing patients with complex pain disorders. Peripheral nerve stimulation should be used judiciously as an adjunct for chronic and acute postoperative pain following adequate patient screening and positive diagnostic nerve block or stimulation trial.

Multidisciplinary Firms and the Treatment of Chronic Pain: A Case Study of Low Back Pain

Sixteen million people suffer with chronic low back pain and related healthcare expenditures can be as high as $USD 635 billion. Current pain treatments help a significant number of acute pain patients, allowing them to obtain various treatments and then “exit the market for pain services” quickly. However, chronic patients remain in pain and need multiple, varying treatments over time. Often, a single pain provider does not oversee their care. Here, we analyze the current pain market and suggest ways to establish a new treatment paradigm. We posit that more cost effective treatment and better pain relief can be achieved with multi-disciplinary care with a provider team overseeing care.

Dorsal Column Stimulation and Cannabinoids in the Treatment of Chronic Nociceptive and Neuropathic Pain: a Review of the Clinical and Pre-clinical Data

PURPOSE OF REVIEW

The main objective of this review is to appraise the literature on the role of spinal cord stimulation (SCS), cannabinoid therapy, as well as SCS and cannabinoid combination therapy for the management of chronic neuropathic and nociceptive pain. Current research suggests that SCS reduces pain and increases functional status in carefully selected patients with minimal side effects.

RECENT FINDINGS

As cannabinoid-based medications become a topic of increasing interest in pain management, data remains limited regarding the clinical efficacy of cannabinoids for pain relief. Furthermore, from a mechanistic perspective, although various pain treatment modalities utilize overlapping pain-signaling pathways, clarifying whether cannabinoids work synergistically with SCS via shared mechanisms remains to be determined. In considering secondary outcomes, the current literature suggests cannabinoids improve quality of life, specifically sleep quality, and that SCS decreases opioid consumption, increases functional capacity, and decreases long-term healthcare costs. These findings, along with the high safety profiles of SCS and cannabinoids overall, incentivize further exploration of cannabinoids as an adjunctive therapy to SCS in the treatment of neuropathic and nociceptive pain.

Does Neuromodulation Reduce Chronic Pain Patient Emergency Department Utilization?

BACKGROUND

Chronic pain (CP) affects roughly 100 million adults in the United States. These subjects present disproportionately to the emergency department (ED). Neuromodulation (NM) has been shown to reduce ED visits longitudinally in subjects.

OBJECTIVE

To compare ED utilization rates between subjects with CP with and without NM.

METHODS

Subjects with failed back surgery syndrome, complex regional pain syndrome, or neuropathic pain diagnosis who visited the hospital between January 1, 2019, and December 31, 2019, were included. Subjects were divided into a NM-treated cohort and a non-NM cohort. Demographic information, medications, and pain provider visits were obtained. Pain-related ED visits between 2017 and 2019 were compared.

RESULTS

A total of 2516 subjects were identified; 291 (11.6%) previously underwent NM. The non-NM cohort had significantly higher rate of pain-related ED visits compared with the NM cohort (15.1% vs 10.0%, P = .018). Younger age (odds ratio [OR] = 0.888 [0.843-0.935]), shorter distance to the hospital (OR = 0.807 [0.767-0.849]), lower household income (OR = 0.865 [0.831-0.901]), opioid use (OR = 1.375 [1.291-1.465]), nonopioid use (OR = 1.079 [1.033-1.128]), and non-NM therapy (OR = 1.751 [1.283-2.390]) were significant predictors of ED visits. Opioid use was the only significant predictor (OR = 6.124 [1.417-26.473]) associated with ED visits in the NM cohort.

CONCLUSION

Subjects who underwent NM had fewer visits to the ED when compared with similar subjects who received conventional treatment. Opioid use prompted increased ED utilization in both cohorts. We posit that NM leads to improvement in pain outcomes, integration with multidisciplinary pain specialists, and reduction in severity and frequency of acute pain exacerbations, thereby limiting health care resource utilization.

Procedure-Related Outcomes Including Readmission Following Spinal Cord Stimulator Implant Procedures: A Retrospective Cohort Study

BACKGROUND

Spinal cord stimulation (SCS) has been shown to reduce opioid consumption, reduce pain, improve quality of life compared to conventional therapy, and be more effective than spine reoperation in carefully selected patients. In this study, we evaluate readmissions after SCS implantation procedures, costs, predictors, and etiologies for readmission following implantation procedures.

METHODS

The study was a retrospective cohort using the National Readmissions Database from 2013 to 2017. Administrative billing codes were used to identify patients undergoing SCS implantation procedures. The primary outcome of our study was 30-day readmission following the SCS implantation procedure. Continuous outcomes were compared between groups using the Student t test or Wilcoxon rank sum test. In addition, multivariable predictors of 30-day readmission were assessed by hierarchical logistic regression analysis.

RESULTS

A total of 3737 (26.7% open surgical SCS implants [OS-SCS]) individuals admitted to the hospital for SCS implantation were included in the final cohort analysis. The cohort consisted of predominantly female patients (58.71%) and in the 50- to 64-year age group (35.46%). Patients who underwent open surgical SCS implantation had a longer length of stay during the initial admission and a higher 30-day readmission rate (9.4% vs 7% P = .01). OS-SCS, older age, lower socioeconomic status, patients with specific comorbidities (ie, hypertension or chronic obstructive pulmonary disease [COPD]), and home discharge are associated with readmission.

CONCLUSIONS

Readmission rates after SCS implantation are around 7.7% in the United States. Infection and postoperative complications remain the top etiologies for readmission. Open surgical SCS implantation is associated with more extended initial hospitalization and a higher rate of readmission when compared to percutaneous SCS implantation procedures.

Health-Care Utilization and Outcomes with 10 kHz Spinal Cord Stimulation for Chronic Refractory Pain

Background

Chronic pain is a common condition associated with decreased quality of life and increased health-care costs. Opioid analgesics are routinely used to treat chronic pain despite limited evidence of long-term efficacy. Spinal cord stimulation at a frequency of 10 kilohertz (10kHz-SCS) has been shown to be effective for treating chronic pain.

Objective

This study was conducted to evaluate the effects of 10kHz-SCS on patients’ pain intensity, volume of pain interventions, and opioid intake in a real-world setting.

Study Design

This study was a retrospective review of patient data.

Setting

The study was conducted at a single, community-based clinic.

Methods

Outcomes including pain relief, quality of life, opioid intake, and rate of health-care usage were evaluated using data from patients who were implanted with a 10kHz-SCS device to treat chronic pain. These outcomes were then compared for the pre- and post-implant periods.

Results

A total of 47 patients with a mean follow-up duration of 15.6 ± 6.2 months were included in this analysis. Mean pain relief was 73 ± 22% and 89% were responders at the final follow-up visit. The rate of medical interventions fell from 3.48±3.05 per year before starting 10kHz-SCS to 0.49±1.16 per year afterward (P < 0.001). Of 30 patients with available opioid consumption data, 89% maintained or decreased their intake after implant.

Conclusion

Retrospective data from a single center, with minimal exclusion criteria shows clinically significant pain relief with 10kHz-SCS, accompanied by significant indirect benefits including stable or reduced opioid use and reduced interventional procedures.

Real-World Cost-Effectiveness Analysis of Spinal Cord Stimulation vs Conventional Therapy in the Management of Failed Back Surgery Syndrome

Purpose

Failed back surgery syndrome (FBSS) causes disability and lowers health-related quality of life (HRQoL) for patients. Many patients become refractory to conventional medical management (CMM) and spinal cord stimulation (SCS) is advised. However, comparative cost-effectiveness research of both clinical approaches still lacks further evidence. This probabilistic cost-effectiveness analysis compares CMM versus SCS plus CMM in FBSS patients for a 5-year period in Spain.

Patients and Methods

Patient-level data was obtained from a 2-year real-world study (SEFUDOCE) of adults diagnosed with FBSS who were treated with CMM or SCS. Incremental cost-effectiveness ratios (ICER) were estimated in terms of direct clinical cost and quality-adjusted life years (QALYs). Costs (€ for 2019) were estimated from the Spanish National Health Service (NHS) perspective. We applied a yearly discount rate of 3% to both costs and outcomes and performed a probabilistic sensitivity analysis using bootstrapping.

Results

After 2 years, the health-related quality of life measured by the EQ-5D displayed greater improvements for SCS patients (00.39) than for improved CMM patients (0.01). The proportion of SCS patients using medication fell substantially, particularly for opioids (-49%). In the statistical model projection, compared with the CMM group at year 5, the SCS group showed an incremental cost of € 15,406 for an incremental gain of 0.56 0.56 QALYs, for an ICER of € 27,330, below the €30,000 willingness-to-pay threshold for Spain. SCS had a 79% of probability of being cost-effective.

Conclusion

SCS is a cost-effective treatment for FBSS compared to CMM alone based on real-world evidence.

Spinal cord stimulation: a real-world data analysis on outcomes and differences between rechargeable and non-rechargeable implantable pulse generators

OBJECTIVE

In this analysis, we examined differences between rechargeable and non-rechargeable spinal cord stimulation (SCS) devices in patients with pain.

METHODS

We conducted a retrospective, longitudinal claims data analysis using a German research database comprising 5 million statutory insured patients (2012-2017). Outcomes of demographics, patient pathways, and health care resource utilization (HCRU) in patients with initial SCS were collected.

RESULTS

Of 150 patients in the database, 73 (49%) received a rechargeable device and 77 (51%) a non-rechargeable device. The average age was 62.5 years (51% female and 49% male patients). A significant decrease over a 3-year follow-up was observed in analgesic prescriptions (-18%), number of patient visits to a physician, and number of patients who were hospitalized. HCRU-related figures for patients with non-rechargeable neurostimulators increased in the last follow-up year whereas the group receiving rechargeable neurostimulators showed a steady decrease.

CONCLUSIONS

SCS seems to be an effective way for patients with chronic pain to decrease pain and improve quality of life. Rechargeable devices seem to be superior to non-rechargeable devices owing to greater longevity and were found to be associated with continuous reduction of pain diagnoses, hospitalization, physician visits, and use of pain medication in our study.

Gabapentinoids Associated With Lower Explantation Rate in 203 Patients With Spinal Cord Stimulation for Failed Back Surgery Syndrome

BACKGROUND

Spinal cord stimulation (SCS) is an effective treatment in failed back surgery syndrome (FBSS). The effect of neuropathic pain medication use on SCS outcome is poorly understood.

OBJECTIVE

To study the effect of gabapentinoid use on SCS outcome measured by trial success, explantation rate and opioid dose reduction during a 2-yr follow-up.

METHODS

The study cohort included 203 consecutive FBSS patients who underwent SCS in a single tertiary center during January 1997 to March 2014. Purchase data of gabapentinoids, opioids, tricyclic antidepressants, serotonin and noradrenaline reuptake inhibitors, and benzodiazepines during January 1995 to March 2016 were retrieved from national registries.

RESULTS

In multivariate Cox regression analysis, patients using gabapentinoids had significantly fewer explantations during the 2-yr follow-up (hazard ratio [HR] 0.2, 95% CI 0.04-0.81, P = .03). In contrast, patients with opioid use of >40 morphine milligram equivalent before implantation had significantly more explantations (HR 6.7, 95% CI 2.5-18, P < .01). In bivariate logistic regression analysis adjusted for patient specific factors, year of SCS implantation, use of neuropathic pain medication, opioids, and benzodiazepines, patients using gabapentinoids significantly more often discontinued opioids or reduced their dose by more than 50% during the 2-yr follow-up (odds ratio 5.7, 95% CI 1.4-23, P = .015).

CONCLUSION

The use of gabapentinoids was associated with a significantly lower spinal cord stimulator explantation rate and a higher chance of opioid discontinuation or >50% dose reduction. This indicates that patients with SCS could benefit from concomitant use of gabapentinoids. Prospective randomized trials are warranted to verify this hypothesis.

Low back pain

Low back pain covers a spectrum of different types of pain (eg, nociceptive, neuropathic and nociplastic, or non-specific) that frequently overlap. The elements comprising the lumbar spine (eg, soft tissue, vertebrae, zygapophyseal and sacroiliac joints, intervertebral discs, and neurovascular structures) are prone to different stressors, and each of these, alone or in combination, can contribute to low back pain. Due to numerous factors related to low back pain, and the low specificity of imaging and diagnostic injections, diagnostic methods for this condition continue to be a subject of controversy. The biopsychosocial model posits low back pain to be a dynamic interaction between social, psychological, and biological factors that can both predispose to and result from injury, and should be considered when devising interdisciplinary treatment plans. Prevention of low back pain is recognised as a pivotal challenge in high-risk populations to help tackle high health-care costs related to therapy and rehabilitation. To a large extent, therapy depends on pain classification, and usually starts with self-care and pharmacotherapy in combination with non-pharmacological methods, such as physical therapies and psychological treatments in appropriate patients. For refractory low back pain, a wide range of non-surgical (eg, epidural steroid injections and spinal cord stimulation for neuropathic pain, and radiofrequency ablation and intra-articular steroid injections for mechanical pain) and surgical (eg, decompression for neuropathic pain, disc replacement, and fusion for mechanical causes) treatment options are available in carefully selected patients. Most treatment options address only single, solitary causes and given the complex nature of low back pain, a multimodal interdisciplinary approach is necessary. Although globally recognised as an important health and socioeconomic challenge with an expected increase in prevalence, low back pain continues to have tremendous potential for improvement in both diagnostic and therapeutic aspects. Future research on low back pain should focus on improving the accuracy and objectivity of diagnostic assessments, and devising treatment algorithms that consider unique biological, psychological, and social factors. High-quality comparative-effectiveness and randomised controlled trials with longer follow-up periods that aim to establish the efficacy and cost-effectiveness of low back pain management are warranted.

The Effectiveness of Spinal Cord Stimulation for the Treatment of Axial Low Back Pain: A Systematic Review with Narrative Synthesis

OBJECTIVE

Determine the effectiveness of spinal cord stimulation (SCS) for the treatment of axial low back pain (LBP) with or without leg pain.

DESIGN

Systematic review.

SUBJECTS

Persons aged ≥18 with axial LBP with or without accompanying leg pain.

INTERVENTION

Traditional low-frequency, burst, or high-frequency SCS.

COMPARISON

Sham, active standard of care treatment, or none.

OUTCOMES

The primary outcome was ≥50% pain improvement, and the secondary outcome was functional improvement measured six or more months after treatment intervention.

METHODS

Publications in PubMed, MEDLINE, and Cochrane databases were reviewed through September 19, 2019. Randomized or nonrandomized comparative studies and nonrandomized studies without internal controls were included. The Cochrane Risk of Bias Tool and GRADE system were used to assess individual study characteristics and overall quality.

RESULTS

Query identified 262 publications; 17 were suitable for inclusion. For high-frequency SCS, the only level 1 study showed that 79% (95% confidence interval = 70-87%) of patients reported ≥50% pain improvement. For low-frequency SCS, the only level 1 study reported no categorical data for axial LBP-specific outcomes; axial LBP improved by a mean 14 mm on the visual analog scale at six months. Meta-analysis was not performed due to study heterogeneity.

CONCLUSIONS

According to GRADE, there is low-quality evidence that high-frequency SCS compared with low-frequency SCS is effective in patients with axial LBP with concomitant leg pain. There is very low-quality evidence for low-frequency SCS for the treatment of axial LBP in patients with concomitant leg pain. There is insufficient evidence addressing the effectiveness of burst SCS to apply a GRADE rating.

The Use of Remote Programming for Spinal Cord Stimulation for Patients With Chronic Pain During the COVID-19 Outbreak in China

ObjectiveS

Due to the impact of COVID-19 epidemic, face-to-face follow-up treatments for patients with chronic pain and implanted spinal cord stimulation (SCS) devices are forced to be delayed or stopped. This has led to more follow ups being done remotely. Meanwhile, with the development of 4G/5G networks, smartphones, and novel devices, remote programming has become possible. Here, we investigated the demand and utility of remote follow-ups including remote programming for SCS for patients with chronic pain.

Materials and Methods

A questionnaire including questions on demographic characteristics, pain history, postimplantation life quality, standard follow-up experience, remote follow-up, and remote programming experience was sent to patients diagnosed as chronic intractable pain and treated with SCS during January 2019 to January 2020.

Results

A total of 64 participants completed the questionnaire. About 70% of participants expressed demands for remote follow-ups due to the inconvenience, high costs, and time consumption of traditional follow-up visits. Nearly 97% of participants have attempted remote follow-ups, and about 81% of participants have further tried remote programming. Approximately, 96% of them recognized the benefits.

Conclusions

The remote programming was in high demand among participants. Most of the participants have tried remote follow-ups or even remote programming. The remote programming appeared to be more efficient, economic and were widely recognized among participants.

A Retrospective Review of Lead Migration Rate in Patients Permanently Implanted with Percutaneous Leads and a 10 kHz SCS Device

Background

Spinal cord stimulation (SCS) has been used over decades for pain management, but migration of percutaneous leads has been the most common complication. Better surgical techniques and newer SCS technologies likely reduced the incidence of lead migration requiring surgical revision, although data are sparse. This study aimed to retrospectively evaluate the incidence of clinically significant percutaneous lead migration in patients permanently implanted with a 10 kHz SCS system.

Methods

Consecutive patients with chronic trunk and/or limb pain, permanently implanted between January 2016 and June 2019, were included in the analysis. Data were collected from the hospital's electronic medical records and the manufacturer's database. Clinically significant lead migration, defined as diminished pain relief followed by surgery to correct lead location, was assessed at the 6-month follow-up.

Results

At the 6-month follow-up, there were no cases of clinically significant lead migration, average pain relief was 65.2%, 82% of patients had response (≥50% pain relief), improvement of function was noted in 72% of patients, and decrease of medication was observed in 42% of patients. Therapy efficacy was sustained in patients with >12 months follow-up; the average pain relief was 58.5%, and the response rate was 82%.

Conclusions

The surgical techniques in use today are designed to minimise the risk of percutaneous lead migration and may have reduced its incidence. In addition, new SCS systems may give greater opportunity to mitigate cases of minor lead movement using alternative stimulation programs.

Higher Preimplantation Opioid Doses Associated With Long-Term Spinal Cord Stimulation Failure in 211 Patients With Failed Back Surgery Syndrome

Objective

Spinal cord stimulation (SCS) is an effective treatment in failed back surgery syndrome (FBSS). We studied the effect of preimplantation opioid use on SCS outcome and the effect of SCS on opioid use during a two‐year follow‐up period.

Materials and methods

The study cohort included 211 consecutive FBSS patients who underwent an SCS trial from January 1997 to March 2014. Participants were divided into groups, which were as follows: 1) SCS trial only (n = 47), 2) successful SCS (implanted and in use throughout the two‐year follow‐up period, n = 131), and 3) unsuccessful SCS (implanted but later explanted or revised due to inadequate pain relief, n = 29). Patients who underwent explantation for other reasons (n = 4) were excluded. Opioid purchase data from January 1995 to March 2016 were retrieved from national registries.

Results

Higher preimplantation opioid doses associated with unsuccessful SCS (ROC: AUC = 0.66, p = 0.009), with 35 morphine milligram equivalents (MME)/day as the optimal cutoff value. All opioids were discontinued in 23% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.004). Strong opioids were discontinued in 39% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.04). Mean opioid dose escalated from 18 ± 4 MME/day to 36 ± 6 MME/day with successful SCS and from 22 ± 8 MME/day to 82 ± 21 MME/day with unsuccessful SCS (p < 0.001).

Conclusions

Higher preimplantation opioid doses were associated with SCS failure, suggesting the need for opioid tapering before implantation. With continuous SCS therapy and no explantation or revision due to inadequate pain relief, 39% of FBSS patients discontinued strong opioids, and 23% discontinued all opioids. This indicates that SCS should be considered before detrimental dose escalation.