10-kHz Spinal Cord Stimulation for Chronic Postsurgical Pain: Results From a 12-Month Prospective, Multicenter Study

Improvement in Health-Related Quality of Life With Spinal Cord Stimulation in Complex Regional Pain Syndrome: A Single-Center, Retrospective Study

BACKGROUND

Complex regional pain syndrome (CRPS) can profoundly affect many aspects of everyday life. Spinal cord stimulation (SCS) is a potential therapeutic option. This retrospective, single-site evaluation explored health-related quality of life (HRQoL) in individuals with CRPS treated with SCS in our Pain Service.

MATERIALS AND METHODS

All patients aged ≥18 years with fully implanted SCS for CRPS between June 2013 and January 2023 were identified from hospital records. The following data were collected: sex, age, chronic pain diagnosis, CRPS type (I or II), location of CRPS (upper or lower limb), years of CRPS before first SCS implant, SCS system, preimplant and follow-up scores for HRQoL (euroqol 5 dimensions 3 levels [EQ-5D-3L] index score), average pain, worst pain and the influence of pain on aspects of everyday life (all numerical rating scale [NRS]), patient and clinician global impression of change at follow-up, and the occurrence and reasons for revisions and explants. An intention-to-treat approach was used and data statistically analyzed.

RESULTS

The final cohort comprised 83 patients (46 women), with a median (minimum, maximum) follow-up duration of 29 months (seven, 72). There were statistically and clinically significant improvements in HRQoL, despite relatively low pain response rates. The pain response rate was 34% (reduction of ≥30% in average pain NRS); the pain remission rate was 13% (average pain score ≤3 NRS), and all patients had preimplant EQ-5D-3L index values below the population norm of 0.82. However, 60% of patients reported EQ-5D-3L index scores greater than the published minimally important difference of 0.074, and scores were better at follow-up than at preimplant (p < 0.001); 44% of patients and 41% of clinicians reported improved symptoms at the most recent follow-up. Explants occurred in eight of 83 patients (10%).

CONCLUSIONS

Patients had meaningful improvements in HRQoL, which is a key outcome in ascertaining the overall outcome of SCS in CRPS. Randomized controlled clinical trials should build on the findings to improve understanding of the benefits and risks of treating CRPS with SCS.

Variables associated with nonresponders to high-frequency (10 kHz) spinal cord stimulation

INTRODUCTION

The use of spinal cord stimulation (SCS) therapy to treat chronic pain continues to rise. Optimal patient selection remains one of the most important factors for SCS success. However, despite increased utilization and the existence of general indications, predicting which patients will benefit from neuromodulation remains one of the main challenges for this therapy. Therefore, this study aims to identify the variables that may correlate with nonresponders to high-frequency (10 kHz) SCS to distinguish the subset of patients less likely to benefit from this intervention.

MATERIALS AND METHODS

This was a retrospective single-center observational study of patients who underwent 10 kHz SCS implant. Patients were divided into nonresponders and responders groups. Demographic data and clinical outcomes were collected at baseline and statistical analysis was performed for all continuous and categorical variables between the two groups to calculate statistically significant differences.

RESULTS

The study population comprised of 237 patients, of which 67.51% were responders and 32.49% were nonresponders. There was a statistically significant difference of high levels of kinesiophobia, high self-perceived disability, greater pain intensity, and clinically relevant pain catastrophizing at baseline in the nonresponders compared to the responders. A few variables deemed potentially relevant, such as age, gender, history of spinal surgery, diabetes, alcohol use, tobacco use, psychiatric illness, and opioid utilization at baseline were not statistically significant.

CONCLUSION

Our study is the first in the neuromodulation literature to raise awareness to the association of high levels of kinesiophobia preoperatively in nonresponders to 10 kHz SCS therapy. We also found statistically significant differences with greater pain intensity, higher self-perceived disability, and clinically relevant pain catastrophizing at baseline in the nonresponders relative to responders. It may be appropriate to screen for these factors preoperatively to identify patients who are less likely to respond to SCS. If these modifiable risk factors are present, it might be prudent to consider a pre-rehabilitation program with pain neuroscience education to address these factors prior to SCS therapy, to enhance successful outcomes in neuromodulation.

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.

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.

Exploring Patient Satisfaction and Other Outcome Measures With Pain Relief in Spinal Cord Stimulation: A Single-Site, Cohort Audit

Context Spinal cord stimulation (SCS) is an approved treatment for chronic pain of neuropathic origin. Initial research suggests a close relationship between pain relief and patient satisfaction with SCS. Objectives To see whether similar patterns were observed in our center and to identify areas of improvement, this single-site, cohort audit explored the association between pain relief and satisfaction as well as specific factors that influence satisfaction at follow-up in patients with fully implanted SCS. Methods Age, gender, pain condition, SCS system, average pain (numerical rating scale, NRS), and worst pain (NRS) scores at baseline and the most recent follow-up visit were collected. Percentage change in average pain was calculated, and the patients were allocated to one of three pain improvement groups: <30%, 30%-50%, or >50%. A telephone survey explored patient outcomes including patient satisfaction, sleep, fatigue, quality of life (QoL), walking ability, and medication use. Chi-square tests of independence were performed. Results The final sample comprised 87 patients (<30%: n = 26; 30%-50%: n = 29; >50%: n = 32). The pain improvement group was significantly associated with satisfaction (p = 0.010): all patients in the >50% improvement group reported being either very satisfied or somewhat satisfied with SCS. The pain improvement group was also significantly associated with change in sleep (p < 0.001), fatigue (p = 0.001), QoL (p = 0.003), and opioid consumption (p = 0.010). Improvements were most frequently reported in the >50% improvement group. Conclusion Findings point to an association between pain relief and patient satisfaction with SCS. Other factors, including sleep, fatigue, QoL, and opioid consumption, may influence this association and deserve further exploration.

Case study: persistent recovery of hand movement and tactile sensation in peripheral nerve injury using targeted transcutaneous spinal cord stimulation

Peripheral nerve injury can lead to chronic pain, paralysis, and loss of sensation, severely affecting quality of life. Spinal cord stimulation has been used in the clinic to provide pain relief arising from peripheral nerve injuries, however, its ability to restore function after peripheral nerve injury have not been explored. Neuromodulation of the spinal cord through transcutaneous spinal cord stimulation (tSCS), when paired with activity-based training, has shown promising results towards restoring volitional limb control in people with spinal cord injury. We show, for the first time, the effectiveness of targeted tSCS in restoring strength (407% increase from 1.79 ± 1.24 N to up to 7.3 ± 0.93 N) and significantly increasing hand dexterity in an individual with paralysis due to a peripheral nerve injury (PNI). Furthermore, this is the first study to document a persisting 3-point improvement during clinical assessment of tactile sensation in peripheral injury after receiving 6 weeks of tSCS. Lastly, the motor and sensory gains persisted for several months after stimulation was received, suggesting tSCS may lead to long-lasting benefits, even in PNI. Non-invasive spinal cord stimulation shows tremendous promise as a safe and effective therapeutic approach with broad applications in functional recovery after debilitating injuries.

Successful use of differential target multiplexed spinal cord stimulation for chronic postsurgical abdominal pain

Introduction

Recent advances in stimulation techniques have improved the efficacy and expanded the applicability of spinal cord stimulation (SCS). Among these techniques, there are no reports on the efficacy of differential target multiplexed (DTM) SCS for chronic postsurgical pain (CPSP) after abdominal surgery. Therefore, we present the successful use of DTM SCS for CPSP after distal pancreatectomy.

Methods

A 49-year-old man with hypertension and severe chronic low back pain presented with neuropathic CPSP involving the left abdomen in the area of a laparotomy incision. His pain was refractory to conservative treatment and was rated 10 on a numerical rating scale (NRS). He underwent permanent implantation of a pulse generator after a 14-day trial stimulation.

Results

Chronic postsurgical pain was well controlled (NRS 1-2) at a 3-month follow-up with DTM SCS.

Conclusion

Differential target multiplexed SCS can be a new treatment option for neuropathic CPSP that is resistant to conservative treatment. It is important to further examine the characteristics of CPSP and identify appropriate candidates for the successful use of DTM SCS.

Patient-Reported Satisfaction with Using a Rechargeable 10 kHz Spinal Cord Stimulation Device

Introduction

Chronic pain is a common clinical condition and is frequently treated with a variety of medications, but pharmacotherapy is oftentimes not the optimal long-term treatment option. Safe and effective long-term pain relief for trunk and limb pain is available using high-frequency spinal cord stimulation at 10 kHz (10 kHz SCS), which is delivered using a rechargeable implantable pulse generator (IPG). Although rechargeable devices have been shown to reduce patient risk and overall cost by eliminating the need for periodic surgeries to replace depleted non-rechargeable IPGs, there is little published evidence that rechargeable technology is practical and convenient for patients, especially in the context of 10 kHz SCS.

Objective

This analysis of real-world patients implanted with 10 kHz SCS devices was undertaken using patient data from an industry-maintained database to investigate whether there was a substantial burden associated with rechargeable SCS and the degree of patient satisfaction or dissatisfaction with 10 kHz SCS.

Results

This study included 10,391 men and women who were implanted with 10 kHz SCS devices to treat chronic pain of the trunk and/or limbs. They received stimulation for a median of 361 days (180-1550 days), and 65.48% had previous spine surgery. In this patient sample, most patients were satisfied with the efficacy of 10 kHz SCS, including 77% who would repeat the procedure and 71% who would recommend it to other patients with similar pain. In regards to IPG recharging, 70% were satisfied or very satisfied and 19% were neutral, and a majority of patients recharged their device daily for 30 to 60 minutes.

Conclusion

These results indicate most patients do not find IPG recharging inconvenient or burdensome. In addition, IPG recharging is not a barrier to the majority of patients benefitting from 10 kHz SCS for long-term pain relief.

A Pilot Study Comparing Algorithmic Adaptive Conventional Stimulation with High-Dose Stimulation in Chronic Pain Patients

INTRODUCTION

Spinal cord stimulation is an effective method of treatment for chronic pain. We previously showed that programming using accelerometry was advantageous for paresthesia-based stimulation. However, programming can be labor intensive.

OBJECTIVE

Here we focus on standardized programming for both accelerometer-based paresthesia-induced programming (termed "shuffle") and high-dose (HD) subthreshold programming with stimulation delivered over the T9-10 interspace.

METHODS

In this prospective cross-over study, patients received 4 weeks of shuffle programming and 4 weeks of HD programming in a randomized order. In both intervals, contacts overlying T9-10 were programmed. Pain scales with measurements of activity and sleep were collected at the end of each study arm and compared with preoperative baseline scores.

RESULTS

Twelve patients were enrolled, with 10 patients completing this study. Compared with baseline, during the HD study period, significant improvements were seen in worst pain of week (P = 0.03) and current pain (P = 0.04) as rated on Numeric Rating Scale scores and walking on the Activity Test (P = 0.012). No difference was seen from baseline compared with shuffle stimulation or in shuffle stimulation compared with HD stimulation.

CONCLUSION

In this pilot study, we demonstrated that HD stimulation at T9-10 is superior to algorithmic programming of paresthesia-based stimulation. These results compared with our previous work with shuffle suggest that paresthesia-based stimulation may necessitate stimulation of additional contact locations and additional programming to optimize. This algorithmic programming of paresthesia-based stimulation continues to warrant exploration.

Indirect Comparison of 10 kHz Spinal Cord Stimulation (SCS) versus Traditional Low-Frequency SCS for the Treatment of Painful Diabetic Neuropathy: A Systematic Review of Randomized Controlled Trials

Spinal cord stimulation (SCS) is increasingly used to treat painful diabetic neuropathy (PDN). At the time of a recent meta-analysis in this field, data were only available from randomized controlled trials (RCTs) of traditional low-frequency SCS (LF-SCS). However, outcomes from high-frequency 10 kHz SCS treatment are now available. Our study aimed to systematically review the contemporary evidence for SCS in patients with lower limb pain due to PDN and include an indirect comparison of the high- and low-frequency modalities. We searched the PubMed/CENTRAL databases up to 18 August 2022, for peer-reviewed RCTs of SCS that enrolled PDN patients with lower limb pain symptoms. The quality of the evidence was assessed with the Cochrane Risk of Bias tool. Using SCS treatment arm data from the RCTs, we indirectly compared the absolute treatment effect of 10 kHz SCS and LF-SCS. Results are presented in tables and forest plots. This systematic review was reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines. Three RCTs met our eligibility criteria, including the recent 10 kHz SCS RCT (N = 216, 90 implanted) and 2 others that examined LF-SCS (N = 36, 17 implanted; N = 60, 37 implanted). Our analysis of 6-month data found clinically meaningful pain relief with each SCS modality. However, significantly greater pain reduction was identified for 10 kHz SCS over LF-SCS: average pain reduction in the 10 kHz SCS cohort was 73.7% compared with 47.5% in the pooled LF-SCS group (p < 0.0001). In the permanent implant subset, the 50% pain reduction responder rate was 83.3% in the 10 kHz SCS cohort versus 63.0% in the pooled LF-SCS group (p = 0.0072). The overall risk of bias of each included RCT was deemed high, mainly due to the absence of patient blinding. Our analysis indicates that paresthesia-free 10 kHz SCS can provide superior pain relief and responder rate over LF-SCS for managing PDN patients refractory to conventional medical management.

The painful shoulder arthroplasty: appropriate work-up and review of interventional pain treatments

Shoulder arthroplasty is a successful surgical procedure for several conditions when patients become refractory to conservative management modalities. Unfortunately, some patients experience persistent chronic pain after shoulder arthroplasty. These individuals should undergo a comprehensive evaluation by an orthopedic surgeon to determine whether structural pathology is responsible for the pain and to decide whether reoperation is indicated. At times, a surgical solution does not exist. In these circumstances, a thorough and specific plan for the management of persistent chronic pain should be developed and instituted. In this article, we review common reasons for persistent pain after shoulder arthroplasty and outline the evaluation of the painful shoulder arthroplasty. We then provide a thorough review of interventional pain management strategies. Finally, we hypothesize developments in our field that might provide better outcomes in the future for patients suffering with chronic intractable pain after shoulder arthroplasty.

The Prevalence of Elevated Impedances and Magnetic Resonance Imaging Ineligibility Following Implantation of 10 kHz Spinal Cord Stimulation Devices: A Retrospective Review

OBJECTIVES

Spinal cord stimulation (SCS) is increasingly utilized in the treatment of multiple chronic pain conditions. However, patients will continue to experience other medical issues and the potential for future magnetic resonance imaging (MRI) needs must not be overlooked. SCS devices have device-specific MRI conditional labeling and if impedances are elevated the patient may not be able to obtain an MRI. With 10 kHz SCS devices specifically, an impedance value above 10,000 ohms (Ω) is MRI ineligible. The primary objective of this article was to report the incidence of elevated impedances with a multilumen lead design per electrode, per lead, and to describe the total number of MRI ineligible patients due to elevated impedances using 10 kHz SCS cutoff values. The secondary objective was to determine whether certain patient demographics or surgery characteristics put patients at increased risk of elevated impedances.

MATERIALS AND METHODS

We performed a retrospective review of 327 patients who were implanted with a 10 kHz SCS device between January 2015 and November 2020. Regression models were fitted to determine associations between MRI ineligibility status with clinical characteristics including age, sex, BMI, lead location, implantable pulse generator (IPG) location, and time since implant.

RESULTS

We found elevated impedances with subsequent MRI ineligibility in 13 patients (4.0%). Regression analysis did not identify any associations with MRI ineligibility and patient risk factors including age, sex, body mass index, lead location, IPG location, and follow-up time since implant.

CONCLUSION

We found the prevalence of elevated impedances above 10,000 Ω to be 4% of implanted patients. This information is important for patients and physicians alike and should be considered when device selection is occurring in the pre-operative visits.

High-Frequency 10-kHz Spinal Cord Stimulation Improves Health-Related Quality of Life in Patients With Refractory Painful Diabetic Neuropathy: 12-Month Results From a Randomized Controlled Trial

Objective

To evaluate high-frequency (10-kHz) spinal cord stimulation (SCS) treatment in refractory painful diabetic neuropathy.

Patients and Methods

A prospective, multicenter randomized controlled trial was conducted between Aug 28, 2017 and March 16, 2021, comparing conventional medical management (CMM) with 10-kHz SCS+CMM. The participants had hemoglobin A1c level of less than or equal to 10% and pain greater than or equal to 5 of 10 cm on visual analog scale, with painful diabetic neuropathy symptoms 12 months or more refractory to gabapentinoids and at least 1 other analgesic class. Assessments included measures of pain, neurologic function, and health-related quality of life (HRQoL) over 12 months with optional crossover at 6 months.

Results

The participants were randomized 1:1 to CMM (n=103) or 10-kHz SCS+CMM (n=113). At 6 months, 77 of 95 (81%) CMM group participants opted for crossover, whereas none of the 10-kHz SCS group participants did so. At 12 months, the mean pain relief from baseline among participants implanted with 10-kHz SCS was 74.3% (95% CI, 70.1-78.5), and 121 of 142 (85%) participants were treatment responders (≥50% pain relief). Treatment with 10-kHz SCS improved HRQoL, including a mean improvement in the EuroQol 5-dimensional questionnaire index score of 0.136 (95% CI, 0.104-0.169). The participants also reported significantly less pain interference with sleep, mood, and daily activities. At 12 months, 131 of 142 (92%) participants were "satisfied" or "very satisfied" with the 10-kHz SCS treatment.

Conclusion

The 10-kHz SCS treatment resulted in substantial pain relief and improvement in overall HRQoL 2.5- to 4.5-fold higher than the minimal clinically important difference. The outcomes were durable over 12 months and support 10-kHz SCS treatment in patients with refractory painful diabetic neuropathy.

Trial registration

clincaltrials.gov Identifier: NCT03228420.

Advances in targeting central sensitization and brain plasticity in chronic pain

Maladaptation in sensory neural plasticity of nociceptive pathways is associated with various types of chronic pain through central sensitization and remodeling of brain connectivity. Within this context, extensive research has been conducted to evaluate the mechanisms and efficacy of certain non-pharmacological pain treatment modalities. These include neurostimulation, virtual reality, cognitive therapy and rehabilitation. Here, we summarize the involved mechanisms and review novel findings in relation to nociceptive desensitization and modulation of plasticity for the management of intractable chronic pain and prevention of acute-to-chronic pain transition.

Neuromodulation in the Treatment of Painful Diabetic Neuropathy: A Review of Evidence for Spinal Cord Stimulation

BACKGROUND

Neuropathies, the most common complication of diabetes, manifest in various forms, including entrapments, mononeuropathies or, most frequently, a distal symmetric polyneuropathy. Painful diabetic neuropathy (PDN) in the classic "stocking" distribution is a disease of increasing prevalence worldwide and a condition for which standard medical treatment only provides modest relief. Neuromodulation offers a potential alternative to pharmacotherapies given its demonstrated efficacy in other refractory chronic neuropathic pain syndromes. High-quality evidence from randomized controlled trials (RCTs) is available in these other settings for two approaches to spinal cord stimulation (SCS): (1) conventional low-frequency SCS (LF-SCS), which modulates axonal activity in the dorsal column and is paresthesia-dependent, and (2) high-frequency SCS delivered at 10 kilohertz (10 kHz SCS), which targets neurons in the superficial dorsal horn and is paresthesia-independent.

METHOD

This review examines the evidence for SCS from published RCTs as well as prospective studies exploring the safety and effectiveness of treating PDN with neuromodulation.

RESULTS

Two RCTs enrolling 60 and 36 participants with PDN showed treatment with LF-SCS reduced daytime pain by 45% to 55% for up to two years. An RCT testing 10 kHz SCS versus conventional medical management (CMM) in 216 participants with PDN revealed 76% mean pain relief after six months of stimulation. None of the studies revealed unexpected safety issues in the use of neuromodulation in this patient population.

CONCLUSION

These well-designed RCTs address the unmet need for improved PDN therapies and provide data on the safety, effectiveness, and durability of SCS therapy.

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.

Efficacy and Safety of 10 kHz Spinal Cord Stimulation Using Cervical and Thoracic Leads: A Single-Center Retrospective Experience

INTRODUCTION

Spinal cord stimulation (SCS) with lower thoracic leads has been studied extensively. However, the evidence base for cervical SCS is less well developed, and reports of multiarea SCS lead placement are uncommon. Therefore, this single-center retrospective study evaluated outcomes from 10-kHz SCS with cervical or combined cervical and thoracic lead placement.

METHOD

All patients that underwent a 10-kHz SCS trial with either cervical or combined cervical and thoracic lead placement between 2015 and 2020 were included in our study. We reviewed patient's charts for demographic information, lead placement, and pain scores up to 48 months after implantation.

RESULTS

Of the 105 patients that underwent a 10-kHz SCS trial during the review period, 92 (88%) had back/neck or extremity pain that responded to therapy (≥ 50% pain relief from baseline) and received a permanent system. Sixty-two of these patients (67%) were implanted with combined cervical and thoracic leads, while 30 (33%) received cervical-only leads. Pain relief in both regions exceeded 60% at most visits throughout the 48-month study period. Throughout follow-up, the responder rate in both pain areas was consistently ≥ 70%. No unexpected adverse events occurred.

CONCLUSION

The 10-kHz SCS provided effective and durable pain relief with either cervical or combined cervical and thoracic leads. The efficacy and safety profile of both applications appears to be comparable to lower thoracic SCS. Our results suggest that 10-kHz SCS is a useful paresthesia-free therapeutic option for chronic neuropathic pain originating in the cervical area, as well as more complex multiarea pain presentations.

Auditory change-related cortical response is associated with hypervigilance to pain in healthy volunteers

Background

Patients with chronic pain exhibit hypervigilance (heightened responsiveness to stimuli) to innocuous auditory stimuli as well as noxious stimuli. “Generalized hypervigilance” suggests that individuals who show heightened responsiveness to one sensory system also show hypervigilance to other modalities. However, research exploring the existence of generalized hypervigilance in healthy subjects is limited.

Methods

We investigated whether hypervigilance to pain is associated with auditory stimuli in healthy subjects using the pain vigilance and awareness questionnaire (PVAQ) and auditory change‐related cortical responses (ACRs). ACRs are thought to reflect a change detection system, based on preceding sensory memory. We recorded ACRs under conditions that varied in terms of the accumulation of sensory memory as follows: short‐ACR, with short preceding continuous stimuli and long‐ACR, with long preceding continuous stimuli. In addition, the attention to pain (PVAQ‐AP) and attention to changes in pain (PVAQ‐ACP) subscales were evaluated.

Results

Amplitudes of long‐ACR showed significant positive correlations with PVAQ‐ACP, whereas those of short‐ACR did not show any significant correlations.

Conclusions

Generalized hypervigilance may be observed even in healthy subjects. ACR may be a useful index to evaluate the hypervigilance state in the human brain.

Decreased Opioid Consumption and Durable Pain Relief in Patients Treated with 10 kHz SCS: A Retrospective Analysis of Outcomes from Single-Center

Background

Chronic pain is frequently treated with opioid analgesics, but there is limited evidence for efficacy for chronic use of opioids and the drugs pose significant risks to patients’ physical and mental health. Spinal cord stimulation delivered at a frequency of 10,000 Hertz (10 kHz SCS) is a minimally invasive therapy with demonstrated efficacy and safety in treating chronic pain that has also been associated with decreased opioid use.

Objective

To evaluate opioid reduction and pain relief in real-world cohort.

Study Design

Retrospective review.

Setting

Single center.

Patients and Methods

Consecutive patients who were implanted with 10 kHz SCS devices from December 1, 2015, to June 30, 2020 for the treatment of chronic pain in the trunk or lower limbs were included. Changes in opioid use following 10 kHz SCS treatment were extracted from electronic medical records, and patient-reported pain relief, improvement in function and sleep were extracted from manufacturer’s database. Responder rate was defined as the proportion of patients with at least 50% pain relief. Anonymised results from descriptive analysis of the data are reported.

Results

At last follow-up (median 21.4 months), mean daily opioid dose fell by 48.4 morphine milligram equivalents (MME), and fewer patients used opioids. Mean pain relief in these patients was 57% ± 4%, and responder rate was 68% at last recorded follow-up. Interestingly, pain relief (66%) and responder rate (86%) were higher in patients with 1 year or more. Finally, 50% of patients reported improved sleep, and 73% reported improvement in function at last recorded follow-up after treatment with 10 kHz SCS.

Conclusion

These results support 10 kHz SCS as a safe and effective treatment of chronic pain in real-world patients with secondary benefits to opioid consumption and measures of patients’ quality of life.

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.

High-frequency (10 kHz) spinal cord stimulation for the treatment of focal, chronic postsurgical neuropathic pain: results from a prospective study in Belgium

Aim: Chronic postsurgical pain (CPSP) is a common complication of surgery. This study was conducted to evaluate the efficacy and safety of paresthesia-free, 10-kHz spinal cord stimulation (SCS) as a treatment for CPSP. Patients & methods: Subjects in this prospective, single-arm study had an average pain intensity of ≥5 cm on a 10-cm visual analog scale. The subjects who had pain relief of ≥50% (response) with temporary trial stimulation were permanently implanted with 10-kHz SCS and assessed for 1 year. Results: At 12 months, 94% of subjects were responders to 10-kHz SCS, and 88% had pain remission (visual analog scale ≤2.5 cm). Conclusion: The pain relief was durable in CPSP subjects and the safety profile of 10-kHz SCS was as expected. Clinical trial registration: VT005076953 (Privacy Commission of Belgium).

Paresthesia-Based Versus High-Frequency Spinal Cord Stimulation: A Retrospective, Real-World, Single-Center Comparison

OBJECTIVE

Spinal cord stimulation (SCS) has become a common treatment modality for chronic pain of various etiologies. Over the past two decades, significant technological evolution has occurred in the SCS space, and this includes high-frequency (10 kHz) stimulation. Level I evidence exists reporting superiority of 10 kHz SCS over traditional SCS, however, conflicting reports have been published. The primary objective was to report site-collected real-world patient reported percentage improvement in pain scale (PR-PIPS) with traditional SCS and 10 kHz SCS from a single, academic medical center.

MATERIALS AND METHODS

This study was a single-center retrospective review to determine PR-PIPS of traditional SCS and 10 kHz SCS in those patients implanted for at least 12 months. Data were collected by two independent physicians not involved with the implant surgery to minimize bias in the data collection process. PR-PIPS and other clinical variables were abstracted either via chart review or via phone call for patients who were at least 12 months post-implant at the last clinical follow-up.

RESULTS

A total of 163 implanted patients (traditional stimulation n = 85; high-frequency stimulation n = 78) were identified. Twenty-two explants (traditional stimulation n = 10; high-frequency stimulation n = 12) were performed (13.5%). Seventy-five total remaining SCS implants utilizing traditional stimulation and 66 total remaining SCS implants utilizing high-frequency stimulation were included. There was no difference in PR-PIPS between traditional stimulation (50.6% ± 30.1%) and high-frequency stimulation (47.6% ± 31.5%) in the adjusted linear regression model in a variety of implant indications (p = 0.399). There was no difference in frequency of patient categorization into various thresholds of percentage pain relief based on type of stimulation. The most common reasons for explant were loss of efficacy (50.0%) and infection (40.0%) in the traditional cohort, and loss of efficacy (58.3%) in the high-frequency cohort.

CONCLUSIONS

This study adds further evidence to the published literature that successful long-term results can be achieved with SCS. Our retrospective analysis did not find a statistically significant difference in PR-PIPS between traditional stimulation and high-frequency stimulation in a variety of indications over an average follow-up of nearly two years. Notably, there were statistically significant differences in treatment indications and primary sites of pain between the two patient cohorts, and this should be considered when interpreting the results.

Management of Chronic and Neuropathic Pain with 10 kHz Spinal Cord Stimulation Technology: Summary of Findings from Preclinical and Clinical Studies

Since the inception of spinal cord stimulation (SCS) in 1967, the technology has evolved dramatically with important advancements in waveforms and frequencies. One such advancement is Nevro’s Senza^® SCS System for HF10, which received Food and Drug and Administration (FDA) approval in 2015. Low-frequency SCS works by activating large-diameter Aβ fibers in the lateral discriminatory pathway (pain location, intensity, quality) at the dorsal column (DC), creating paresthesia-based stimulation at lower-frequencies (30–120 Hz), high-amplitude (3.5–8.5 mA), and longer-duration/pulse-width (100–500 μs). In contrast, high-frequency 10 kHz SCS works with a proposed different mechanism of action that is paresthesia-free with programming at a frequency of 10,000 Hz, low amplitude (1–5 mA), and short-duration/pulse-width (30 μS). This stimulation pattern selectively activates inhibitory interneurons in the dorsal horn (DH) at low stimulation intensities, which do not activate the dorsal column fibers. This ostensibly leads to suppression of hyperexcitable wide dynamic range neurons (WDR), which are sensitized and hyperactive in chronic pain states. It has also been reported to act on the medial pathway (drives attention and pain perception), in addition to the lateral pathways. Other theories include a reversible depolarization blockade, desynchronization of neural signals, membrane integration, glial–neuronal interaction, and induced temporal summation. The body of clinical evidence regarding 10 kHz SCS treatment for chronic back pain and neuropathic pain continues to grow. There is high-quality evidence supporting its use in patients with persistent back and radicular pain, particularly after spinal surgery. High-frequency 10 kHz SCS studies have demonstrated robust statistically and clinically significant superiority in pain control, compared to paresthesia-based SCS, supported by level I clinical evidence. Yet, as the field continues to grow with the technological advancements of multiple waveforms and programming stimulation algorithms, we encourage further research to focus on the ability to modulate pain with precision and efficacy, as the field of neuromodulation continues to adapt to the modern healthcare era.

Neuromodulation techniques for cancer pain management

PURPOSE OF REVIEW

Advanced pain management techniques may be indicated in 5-15% of cancer patients. Despite this, a recent review identified that, over the course of 1 year in England, only 458 patients received a procedure intended to provide analgesia and only 30 patients had intrathecal drug delivery (ITDD) devices implanted. This article describes the emerging evidence for ITDD in cancer pain and provides a narrative review of other neuromodulatory techniques (including spinal cord stimulation, peripheral nerve stimulation and acupuncture), approaches that might be employed to address this area of significant unmet clinical need.

RECENT FINDINGS

Numerous studies have been published within the last year reporting positive outcomes associated with ITDD in cancer pain management. Neuromodulation represents an important strategy in the management of persistent pain. Whilst the nonmalignant pain evidence-base is rapidly growing, it remains sparse for cancer pain management. The growing cohort of cancer survivors may significantly benefit from neuromodulatory techniques.

SUMMARY

ITDD and other neuromodulatory techniques for cancer pain management appear underutilised in the UK and offer the prospect of better treatment for cancer patients with refractory pain or intolerable side-effects from systemic analgesics.

Efficacy and Safety of 10 kHz Spinal Cord Stimulation for the Treatment of Chronic Pain: A Systematic Review and Narrative Synthesis of Real-World Retrospective Studies

10 kHz spinal cord stimulation (SCS) is increasingly utilized globally to treat chronic pain syndromes. Real-world evidence complementing randomized controlled trials supporting its use, has accumulated over the last decade. This systematic review aims to summarize the retrospective literature with reference to the efficacy and safety of 10 kHz SCS. We performed a systematic literature search of PubMed between 1 January 2009 and 21 August 2020 for English-language retrospective studies of ≥3 human subjects implanted with a Senza® 10 kHz SCS system and followed-up for ≥3 months. Two independent reviewers screened titles/abstracts of 327 studies and 46 full-text manuscripts. In total, 16 articles were eligible for inclusion; 15 reported effectiveness outcomes and 11 presented safety outcomes. Follow-up duration ranged from 6-34 months. Mean pain relief was >50% in most studies, regardless of follow-up duration. Responder rates ranged from 67-100% at ≤12 months follow-up, and from 46-76% thereafter. 32-71% of patients decreased opioid or nonopioid analgesia intake. Complication incidence rates were consistent with other published SCS literature. Findings suggest 10 kHz SCS provides safe and durable pain relief in pragmatic populations of chronic pain patients. Furthermore, it may decrease opioid requirements, highlighting the key role 10 kHz SCS can play in the medium-term management of chronic pain.

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.

One-Year Results of Prospective Research Study Using 10 kHz Spinal Cord Stimulation in Persistent Nonoperated Low Back Pain of Neuropathic Origin: Maiden Back Study

PURPOSE

Spinal cord stimulation (SCS) is a recommended treatment for chronic neuropathic pain. Persistent nonoperative low back pain of neuropathic origin has profound negative impacts on patient's lives. This prospective, open label, research study aimed to explore the use of SCS in patients with associated features of central sensitisation such as allodynia and hyperalgesia.

MATERIALS AND METHODS

Twenty-one patients with back pain and hyperalgesia or allodynia who had not had prior spinal surgery underwent a SCS trial followed by full implantation. SCS comprised administering electrical impulses epidurally at a frequency of 10 kHz and pulse width of 30 μsec. Patients attended follow-up visits after 6 and 12 months of SCS. Repeated measure ANOVAs/Friedman tests explored change after 6 and 12 months of 10 kHz SCS. Independent sample t-tests/Mann-Whitney U tests examined differences in response after 12 months of 10 kHz SCS.

RESULTS

Back and leg pain, quality of life (QoL), pain-related disability, and morphine equivalence significantly improved compared with baseline following 6 and 12 months of 10 kHz SCS. There were no increases in the consumption of opioids, amitriptyline, gabapentin or pregabalin in any patient. After 12 months of treatment, 52% encountered ≥50% improvement in back pain, 44% achieved remission (0-3 cm back pain VAS), 40% reported ODI scores between 0 and 40 and 60% experienced a reduction of at least 10 ODI points. Patients reporting ≥10-point improvement in ODI had significantly longer pain history durations and experienced significantly greater improvements in back pain, leg pain and QoL than those reporting <10-point improvement in ODI.

CONCLUSION

The 10 kHz SCS improved back and leg pain, QoL, pain-related disability and medication consumption in patients with nonoperative back pain of neuropathic origin. With further research incorporating a sham control arm, the efficacy of 10 kHz SCS in this patient cohort will become more established.