Welcome to the e-INS 2023 Interactive Program

Introduction

In 2019, a European panel developed patient-specific recommendations, considering both clinical and psychosocial factors, on the appropriate referral and selection of patients with chronic pain for spinal cord stimulation (SCS).¹ The panel recommendations (not recommended, recommended, strongly recommended) were embedded in an online educational e-health tool, and were studied in a retrospective study, confirming their applicability and validity.^2,3 We here present the design of the prospective study and results of a feasibility survey.

Materials / Methods

In this European multicentre study, data from patients who are considered for SCS will be prospectively collected by implant centres that have not previously used the e-health tool for patient selection. Furthermore, the tool should not be used during the conduct of the study. Based on the results from the retrospective study and a feasibility survey with 11 implant centres, the size of the patient population was calculated. At the moment of the final decision on SCS, general baseline data, e-health tool variables and the centre decision on SCS will be documented for all patients, but only those eventually receiving SCS will be followed up long term (figure). Patients not receiving SCS will be excluded because of the likelihood of incomplete data. At the end of the study, the diagnostic value of the panel recommendations for patient outcomes will be determined.

Results

The primary aim of the study is to assess the predictive value of the panel recommendations for patient outcomes. To meet this objective, follow-up data on at least 284 patients receiving SCS needs to be collected. Based on the results of the feasibility survey, on average six patients per month per centre have a positive decision on SCS. Of these patients, approximately 25% will have a negative trial, and therefore 355 patients need to be enrolled to achieve sufficient power. In all but one of the centres participating to the feasibility survey, patient selection is furthermore based on a multidisciplinary assessment, with the majority (9/11) always performing a screening trial.

Discussion

Because of the inclusion of centres without tool experience, an internal pilot study with initially only four centres will be conducted to understand the representation of patient profiles across the panel recommendations.

Conclusions

The prospective validation study aims to determine if patient selection for SCS can be improved by applying the appropriateness criteria embedded in an educational e-health tool. An internal pilot study will be conducted first to resolve uncertainties around the distribution of certain patient profiles.

References

1. Thomson S, Huygen F, Prangnell S, De Andrés J, Baranidharan G, Belaïd H, et al. Appropriate referral and selection of patients with chronic pain for spinal cord stimulation: European consensus recommendations and e-health tool. Eur J Pain 2020;26:1169-81.

2. Thomson S, Huygen F, Prangnell S, Baranidharan G, Belaïd H, Bart Billet, et al. Applicability and Validity of an e-Health Tool for the Appropriate Referral and Selection of Patients With Chronic Pain for Spinal Cord Stimulation: Results From a European Retrospective Study. Neuromodulation 2023;26:164-71.

3. Thomson S, Helsen N, Prangnell S, Paroli M, Baranidharan G, Belaïd H, et al. Patient selection for spinal cord stimulation: The importance of an integrated assessment of clinical and psychosocial factors. Eur J Pain 2022;26:1873-81.

Learning Objectives

1. A retrospective study showed that there is a strong relationship between the panel recommendations embedded in an e-health tool and outcomes after SCS

2. The findings from the retrospective study should be validated prospectively to confirm if the e-health tool can improve patient selection for SCS

3. An e-health tool that can predict treatment outcomes can help physicians and policymakers select the appropriate patients for SCS

Introduction

Despite the well-known efficacy of spinal cord stimulation (SCS) in chronic pain management, patient selection in clinical practice remains challenging. The aim of this review is to provide an overview of the factors that can influence the process of patient selection for SCS treatment.

Materials / Methods

A sequential decision-making model is presented within a tier system that operates in clinical practice.

Results

The first level incorporates the underlying disease as a primary indication for SCS, country-related reimbursement rules, and SCS screening–trial criteria in combination with underlying psychological factors as initial selection criteria in evaluating patient eligibility for SCS. The second tier is aligned with the individualized approach within precision pain medicine, whereby individual goals and expectations and the potential need for preoperative optimizations are emphasized. Additionally, this tier relies on results from prediction models to provide an estimate of the efficacy of SCS in the long term. In the third tier, selection bias, MRI compatibility, and ethical beliefs are included, together with recent technological innovations, superiority of specific stimulation paradigms, and new feedback systems that could indirectly influence the decision-making of the physician.

Discussion

This tier system can be considered a sequential decision-making model operating in daily routine care; however, often only the first and sometimes the second tier are openly discussed with the patient. In light of a free, fully informed decision-making process, patients should be fully informed about each tier in order to make an independent decision on whether or not to be considered adequate candidates for SCS and to initiate a treatment trajectory.

Conclusions

Both patients and physicians should be aware of the different aspects that influence patient selection in relation to SCS for pain management to make an independent decision on whether or not to initiate a treatment trajectory with SCS.

References

None.

Learning Objectives

1. To learn about individualised pain medicine in relation to a trajectory with neuromodulation.

2. Be aware of the ethical considerations and bias that is present during patient selection.

3. To gain insight in a sequential decision-making model to improve patient selection with transparancy for both patients and clinicians.

Introduction

Health inequality is an issue influenced by many factors including geography, language and communication barriers, patient preferences, health literacy, waiting times, perceived discrimination, and physician bias. Patient ethnicity and language barrier is a theme that can often underlie many of these factors.

34% of adults in the UK (Adult Chronic Pain Health Survey, 2017) suffer from some degree of chronic pain. This burden has the potential of similar prevalence in patient populations suitable for neuromodulation therapies although this has not been reported before. This is the first quantification of outcomes in patients with language barrier highlighting key issues around SCS efficacy in this population.

Materials / Methods

After local approval, data from 494 patients (May 2021- June 202) in a large tertiary inner-city hospital was reviewed. From this pool 44 patients were identified (9%) whose native language was not English with 31 (70%) being suitable for SCS, demonstrating demand for such services amongst ethnic minority. Data from 25 patients whose first language was not English who underwent SCS was analysed.

Results

Of 25 SCS patients, seven (28%) were eventually explanted which is higher than our average explant rate (4%). In the non-explant group (n=18) mean NRS decreased from 7.88 at baseline to 3.75 at 12 months (n=8) with average EQ5D scores increasing from 0.211 at baseline (n=18) to 0.76 at 12 months (n=8). The data collection is still ongoing, and the final results will be presented at eINS.

Discussion

The 2021 UK census showed that 7.1% of the population were proficient in English but did not use it as their main language, 1.5% of the population could not speak English well and a further 0.3% of the population could not speak English at all. There are certain areas of the UK where the percentage of people unable to speak English were even higher than this national figure (Birmingham, Manchester, City of London – 5.2%, 3.7% and 1.0% respectively). The significant higher explant rate reported could indicate the lack of education and cultural barriers about therapy. Simultaneously the improved EQ5DL and NRS validates the need of therapy to this vulnerable group.

Conclusions

There is a growing demand for healthcare to be delivered to patients who are unable to speak native language. This is first ever study highlighting the outcomes for SCS in patients with language barrier in ethnic minority group.

References

1. Office for National Statistics (ONS), released 29 November 2022, ONS website, statistical bulletin, Language, England and Wales: Census 2021

2. Chronic pain in adults 2017 Health Survey for England, https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/940858/Chronic_Pain_Report.pdf

Learning Objectives

1. There is a growing demand for healthcare to be delivered to patients who are unable to speak native language.

2. This is first ever study highlighting the outcomes for SCS in patients with language barrier in ethnic minority group.

3. The significant higher explant rate reported could indicate the lack of education and cultural barriers about therapy.

Introduction

In a pilot study we showed that it is possible to generate pleasant and pain relieving muscle stimulation in the back by using low frequency SCS stimulation (MuscleSCS). In this following study we wanted to examine whether this technique can improve the treatment of lower back pain.

Materials / Methods

Patients with chronic low back pain had an SCS system (lamitrode) implanted after a trial phase and were then randomly treated with only Burst SCS as defined by De Ridder stimulation, only muscle stimulation or Burst SCS as defined by De Ridder and muscle stimulation combined for 2 weeks respectively.
Thereafter, the patients were treated for another 4.5 months with one of the 3 methods (cross-over possible). Pain ratings (Visual Analogue Scale VAS) were recorded daily, and Questionnaires (Pain Disability Index, PDI; Pain Catastrophizing Scale, PCS; Brief Pain Inventory, BPI) were used at baseline, at 3 and at 6 months.

Results

This is a prospective, multicentric, single-blinded, randomized crossover study. We included 58 patients (9 dropouts) (25 females, mean age 62.3 yrs). All 3 stimulation methods, including muscle stimulation alone, showed a highly significant pain relief when compared to the baseline value (p=0.001). The combined application of Burst SCS as defined by De Ridder with muscle stimulation showed the best results (p=0.032) (Fig.1). PDI, PCS and BPI improved significantly during this treatment. No serious adverse events occurred during this study. 75.5% of the subjects experienced an improvement in their pain as a result of this muscle stimulation.

Figure 1:

A bar graph shows the mean pain scores during study phase 1. The combined use (BM) of Burst SCS as defined by De Ridder (B) and MuscleSCS (M) showed the best results.

Discussion

SCS can adequately treat back pain [1]. So far, however, it has not been possible to adequately treat muscle pain with SCS neuromodulation. However, with low-frequency stimulation of 2-8 Hertz it is possible to reach the muscles by directly stimulating the motor neurons in the anterior horn of the spinal cord. This type of stimulation triggers a massage-like effect in the patient's muscles, which most patients describe as pleasant and pain-relieving.

Conclusions

This study showed that the combined use of SCS and additional low frequency muscle stimulation (MuscleSCS) could significantly improve the outcome of patients suffering from chronic back pain.

References

Eckermann JM, Pilitsis JG, Vannaboutathong C, Wagner BJ, Province-Azalde R, Bendel MA. Systematic Literature Review of Spinal Cord Stimulation in Patients With Chronic Back Pain Without Prior Spine Neuromodulation. 2021 Aug 18

Learning Objectives

MuscleSCS can further improve the treatment of back pain.

Introduction

Refractory axial chronic back pain can be caused by a variety of factors such as stenosis, spondylosis, spondylolisthesis, disc herniation, discogenic pain, and combinations of these. A subset of patients show imaging changes of a mild nature, therefore the exact etiology of the disabling pain can be elusive. This leaves an underserved, proportion of patients with CLBP that lack an identifiable surgically corrective pathology. Spinal cord stimulation is sometimes used to treat these patients but level I evidence is sparse. We present results from DISTINCT (NCT04479787), comparing passive recharge burst to conventional medical management (CMM) in patients suffering from chronic, refractory axial low back pain, who have not had lumbar spine surgery and for whom corrective surgery is not an option.

Materials / Methods

An independent spine surgeon reviewed each case and confirmed a lack of suitable corrective surgical options. Back pain intensity (NRS), back pain-related disability (ODI), catastrophizing (PCS), PROMIS-29 and patient impression of change (PGIC) are assessed at 6 and 12 months. Responders are defined; 50% reduction on NRS, 13-point decrease on ODI or a score < 20, 40% decrease on PCS or a categorical change from clinically catastrophizing, a definite or considerable improvement on PGIC. A descriptive endpoint measured opioid usage using morphine equivalents (MME).

Results

162 subjects were randomized to SCS therapy, 107 to CMM. At 6-months, ITT analysis demonstrated significantly more SCS subjects experienced pain relief compared to CMM (73.1% v’s 6.2%; p<0.0001). A Per Treatment Analysis (PTE) was consistent with 85.3% (95% CI: 76.9-91.5) responding on SCS compared to 6.2% (95% CI:2.0-13.8) on CMM. SCS subjects reported a 45% decrease in MME compared to an 11% decrease in the CMM arm. At 12-months (n=98) results were sustained. NRS was reduced to 2.7 ± 2.2. ODI decreased by 28.5 points ± 16.9 from baseline to 22.8 ± 12.7. 79.2% responded on PCS (12-month score = 7.8 ± 9.6). PROMIS-29 physical function and pain interference improve by 9.3 ± 6.8 and 12.9 ± 8.9 respectively. 77% respond on PGIC.

Discussion

Primary and secondary endpoints demonstrate dramatic improvements in pain, function and pain-related emotional distress and are supported by longer term data 12 months post implant. Greater improvements post-burst therapy are accompanied by a reduction opioid use.

Conclusions

DISTINCT study results demonstrate that passive recharge burst is superior to conventional medical management for patients suffering from severe, debilitating low back pain that cannot be addressed through corrective surgical intervention.

Learning Objectives

1. pain relief in a back pain population not indicated for surgery. RESULT: Significant difference in responder rate

2. functional improvement in the same population. RESULT: Greater score improvement on ODI

3. Support use of composite endpoints in neuromodulation clinical studies: Successful secondary endpoint

Introduction

Non-invasive spinal cord transcutaneous stimulation (scTS) is a neuromodulatory intervention that has the potential to enhance the therapeutic effects of activity-based training (ABT) on upper extremity (UE) function recovery after a spinal cord injury (SCI). The beneficial effects of scTS on function recovery are thought to be due to spinal and supraspinal plasticity mechanisms. However, brain’s role or modulation in scTS-based rehabilitation remains unclear and under-investigated. This study aims to bridge this gap.

Materials / Methods

We present preliminary results obtained with 5 chronic, cervical, complete and incomplete SCI individuals who participated in an ongoing three-arm, multicenter, open-label randomized controlled trial. The protocol consists of a baseline assessment, 60 sessions of intervention (60 sessions of scTS+ABT, 40 sessions of scTS+ABT followed by 20 sessions of ABT alone, or 20 sessions of ABT alone followed by 40 sessions of scTS+ABT), and re-assessment at post-intervention. During the intervention, each participant received UE ABT, with or without the constant targeted scTS applied depending on participants tolerability and deficits. As part of the outcomes evaluation, SCI participants underwent motor and sensorimotor function testing using the UE motor scale (UEMS) as part of the AIS evaluation and the GRASSP scale, respectively. Grey matter volume and resting-state functional connectivity (FC) were measured using structural and functional magnetic resonance imaging (MRI) before and after the 60 sessions of intervention and were analyzed using Cat12 and Conn v12 respectively, while including Pre-to-Post clinical scores changes as covariates.

Results

All participants tolerated the interventions without serious side-effects. All participants improved their motor and sensorimotor UE function (ΔUEMS = +7.8 ± 5.8; ΔGRASSP = +28.2 ± 11). Considering Pre-to-Post UEMS and GRASSP changes, scTS-based training resulted in an increase of grey matter volume of the right ventral, and dorsal premotor cortex respectively. The protocol also resulted in FC changes between regions of the sensorimotor network and of the prefrontal cortex, positively associated with the increase of the functional UE clinical scores.

Discussion

The results provide evidence of supraspinal effects of scTS-based training in chronic SCI individuals and suggest that scTS is a noninvasive intervention that is also able to modulate cortical networks.

Conclusions

Understanding spinal and supraspinal underlying mechanisms of scTS will help optimize scTS-based rehabilitation after CNS injury.

References

None

Learning Objectives

1. Sixty sessions of scTS-based rehabilitation training improve UE sensorimotor function is individuals with complete and incomplete SCI.

2. scTS-based training induces brain's structural and functional changes involving regions of the frontal and prefrontal cortex.

3. The observed brain changes are associated with the training-induced improved UE function.