Passive Recharge Burst Spinal Cord Stimulation Provides Sustainable Improvements in Pain and Psychosocial Function: 2-year Results From the TRIUMPH Study

STUDY DESIGN

Prospective, international, multicenter, single-arm, post-market study.

OBJECTIVE

The aim of this study was to assess long-term safety and effectiveness of spinal cord stimulation using a passive recharge burst stimulation design for chronic intractable pain in the trunk and/or limbs. Herein we present 24-month outcomes from the TRIUMPH study (NCT03082261).

SUMMARY OF BACKGROUND DATA

Passive recharge burst spinal cord stimulation (B-SCS) uniquely mimics neuronal burst firing patterns in the nervous system and has been shown to modulate the affective and attentional components of pain processing.

METHODS

After a successful trial period, subjects received a permanent SCS implant and returned for follow-up at 6, 12, 18, and 24 months.

RESULTS

Significant improvements in physical, mental, and emotional functioning observed after 6 months of treatment were maintained at 2 years. Pain catastrophizing scale (PCS) scores dropped below the population norm. Health-related quality of life on EQ-5D improved across all domains and the mean index score was within one standard deviation of norm. Pain reduction (on NRS) was statistically significant (P < 0.001) at all timepoints. Patient reported pain relief, a stated percentage of improvement in pain, was consistent at all timepoints at 60%. Patients reported significant improvements across all measures including activity levels and impact of pain on daily life. At 24 months, 84% of subjects were satisfied and 90% would recommend the procedure. Subjects decreased their chronic pain medication intake for all categories; 38% reduced psychotropic and muscle relaxants, 46% reduced analgesic, anti-convulsant and NSAIDs, and 48% reduced opioid medication. Adverse events occurred at low rates without unanticipated events.

CONCLUSION

Early positive results with B-SCS were maintained long term. Evidence across multiple assessment tools show that B-SCS can alleviate pain intensity, psychological distress, and improve physical function and health-related quality of life.Level of Evidence: 3.

Burst spinal cord stimulation can attenuate pain and its affective components in chronic pain patients with high psychological distress: results from the prospective, international TRIUMPH study

BACKGROUND CONTEXT

Psychological characteristics such as catastrophizing and depression have been shown to negatively impact outcome prognosis after spinal interventions.

PURPOSE

To evaluate whether high psychological distress, defined as clinically elevated levels of catastrophizing and depression, is associated with poorer outcomes after spinal cord stimulation utilizing a passive recharge burst stimulation design. This proprietary waveform may uniquely attenuate the emotional aspects of chronic pain given its affects on the medial pain pathway projecting to the dorsal anterior cingulate cortex and anterior insula.

STUDY DESIGN/SETTINGS

Data were extracted from the prospective, multi-center, single-arm, international TRIUMPH study. The purpose of TRIUMPH was to assess long-term (2 years) safety and effectiveness of spinal cord stimulation for chronic pain in the trunk and/or limbs using a passive recharge enabled burst spinal cord stimulation (B-SCS) system.

PATIENT SAMPLE

Two subsets of study patients were identified; those with (n=31) and those without (n=54) high psychological distress.

OUTCOME MEASURES

Psychological and functional outcomes as well as pain intensity and impact of pain on life were administered at baseline and all follow intervals. Additionally, patient satisfaction and patient global impression of change were assessed at all follow-up intervals.

METHODS

Psychological distress (PD) was defined as a baseline score of ≥ 30 on the Pain Catastrophizing Scale (PCS) and ≥ 10 on the Patient Health Questionnaire Depression scale (PHQ-9). Nondistressed (ND) patients had scores below these thresholds on both scales. All patients were implanted with a B-SCS system and completed data collection for the 24-month follow-up visit. This study was funded by Abbott. JMH is a consultant for Abbott and has received <$20,000 in lifetime consulting fees from Abbott. SMF is a consultant for Abbott and has received >$50,000 in lifetime consulting fees from Abbott. BB is an Abbott employee. RAC is a former Abbott employee. JJY is a consultant for Abbott and has received <$2,500 in lifetime consulting fees from Abbott.

RESULTS

Of the 128 participants with 24-month data, 31 (24%) and 54 (35%) met the criteria for PD and ND, respectively. Baseline measures indicated a more severe chronic pain profile and worse quality of life in the PD group. Two years after implant, 71% were no longer clinically catastrophizing and 58% were no longer clinically depressed. Notably, more than half of the PD patients on antidepressants discontinued or decreased their medication. Health-related quality of life was 82% higher in the PD group at 24 months, reaching levels similar to the ND group. Psychological distress did not impact outcomes after SCS therapy; composite multi-responder rates were similar in the 2 groups throughout the follow-up period. Patient reported pain relief (58% PD vs. 61% ND) was equivalent in each group. In both groups, 81% were satisfied or very satisfied with the pain relief provided.

CONCLUSIONS

Our results showed that B-SCS appears to be as effective in a chronic pain population with high psychological distress as in those without distress. This may be due to the unique mechanism of action with the stimulation design involving the emotional-affective medial pain pathway in the brain.

Improved Psychosocial and Functional Outcomes and Reduced Opioid Usage Following Burst Spinal Cord Stimulation

Objective

Burst spinal cord stimulation (B‐SCS) has been shown to reduce neuronal firing in the anterior cingulate cortex through selective modulation of the medial pain pathway tract. This pain pathway communicates the affective component of pain processing. The purpose of this study was to assess the effect of B‐SCS on psychosocial functioning and its influence on pain and quality of life.

Materials and Methods

Eligible patients with chronic, intractable pain of the trunk, and/or lower limbs were enrolled. After a successful trial period, subjects received a permanent implant and returned for follow‐up at 6‐ and 12‐months.

Results

In total, 269 patients were enrolled at 22 centers. Trial success rate was 90%. Significant improvements in pain, physical, mental, and emotional functioning were observed from baseline to the 6‐ and 12‐month follow‐up (p < 0.001). Overall, patients had improved quality of life, became more active, and the negative impact of pain on daily life was decreasing. At one year, 81% of subjects were satisfied or very satisfied with their therapy. Subjects showing significant improvements on mental health outcomes reported enhanced pain relief and quality of life scores compared with subjects with continued impaired mental health at follow‐up. At one year, 89% of subjects who were taking opioids at baseline decreased or stayed at the same level of opioid use; 19% stopped taking any opioids. No unanticipated adverse events have been reported.

Conclusions

One‐year outcomes after B‐SCS show improvements across all evaluated psychological measures with the largest impact observed on catastrophizing and depression (the affective component of pain processing). These pain‐related beliefs and behaviors, and not pain intensity, have been shown to put patients at greatest risk of a poor prognosis and quality of life.

Effectiveness and Safety of Dorsal Root Ganglion Stimulation for the Treatment of Chronic Pain: A Pooled Analysis

INTRODUCTION

Since it became available in the mid-2010s, dorsal root ganglion (DRG) stimulation has become part of the armamentarium to treat chronic pain. To date, one randomized controlled trial, and several studies of moderate sample size and various etiologies have been published on this topic. We conducted a pooled analysis to investigate the generalizability of individual studies and to identify differences in outcome between chronic pain etiologic subgroups and/or pain location.

MATERIALS AND METHODS

One prospective, randomized comparative trial and six prospective, single-arm, observational studies were identified that met pre-defined acceptance criteria. Pain scores and patient-reported outcome (PRO) measures were weighted by study sample sizes and pooled. Safety data are reported in aggregate form.

RESULTS

Our analysis included 217 patients with a permanent implant at 12-month follow-up. Analysis of pooled data showed an overall weighted mean pain score of 3.4, with 63% of patients reporting ≥50% pain relief. Effectiveness sub-analyses in CRPS-I, causalgia, and back pain resulted in a mean reduction in pain intensity of 4.9, 4.6, and 3.9 points, respectively. Our pooled analysis showed a pain score for primary affected region ranging from 1.7 (groin) to 3.0 (buttocks) and responder rates of 80% for foot and groin, 75% for leg, and 70% for back. A substantial improvement in all PROs was observed at 12 months. The most commonly reported procedural or device complications were pain at the IPG pocket site, lead fracture, lead migration, and infection.

CONCLUSIONS

DRG stimulation is an effective and safe therapy for various etiologies of chronic pain.

Serum protein N-glycosylation in paediatric non-alcoholic fatty liver disease

OBJECTIVE

We have previously shown the potential of glycomics to distinguish patients with steatosis from patients with non-alcoholic steatohepatitis (NASH) in an adult population. The pattern of disease in paediatric patients is distinct from adults. The objective of this study was to characterize the N -glycomic profile of children with varying degrees of non-alcoholic fatty liver disease (NAFLD) and identify potential biomarker profiles of disease.

METHODS

Serum protein N-glycosylation patterns of 51 paediatric NAFLD patients were assessed with deoxyribonucleic acid sequencer-assisted fluorophore-assisted capillary electrophoresis and compared with histology.

RESULTS

Peak 1 (NGA2F) is the most significantly elevated N-glycan in paediatric NASH patients with peak 5 (NA2) demonstrating the largest decrease. The logarithmically transformed ratio of peak 1 to peak 5 was -0.85 (standard deviation [SD] 0.22) in patients with steatosis and borderline NASH and -0.73 (SD 0.12) in NASH (P = 0.02). The biomarker correlated well with the amount of lobular inflammation with a consistent increase of marker score in ascending stage of lobular inflammation. There was also a trend in differentiating patients with significant fibrosis ≥F2; -0.74 (SD 0.13) from patients with no/minimal fibrosis <F2; -0.86 (SD 0.24), P = 0.06. Analysis of the N-glycans on immunoglobulin G confirmed the undergalactosylation status typical for chronic inflammatory conditions.

CONCLUSIONS

This study is the first glycomic analysis performed in a paediatric NAFLD population. In agreement with the results obtained in adults, B cells play a dominant role in the N-glycan alterations of paediatric NASH patients.

N-glycan based biomarker distinguishing non-alcoholic steatohepatitis from steatosis independently of fibrosis

BACKGROUND

Non-alcoholic fatty liver disease is a spectrum of disorders ranging from steatosis to non-alcoholic steatohepatitis (NASH). Steatosis of the liver is benign, whereas NASH can progress to cirrhosis or even hepatocellular carcinoma. Currently, a liver biopsy is the only validated method to distinct NASH from steatosis.

AIM

The objective of this study was to identify a biomarker specific for NASH based on the N-glycosylation of serum proteins.

METHODS

N-glycosylation patterns were assessed using DNA sequencer-assisted fluorophore-assisted capillary electrophoresis and compared with histology.

RESULTS

Initially, a glycomarker (log[NGA2F]/[NA2]) was developed based on the results obtained in 51 obese non-alcoholic patients scheduled for bariatric surgery. Multivariate analysis showed that our glycomarker had the lowest P-value of all biomarkers in distinguishing NASH from steatosis (P=0.069). The glycomarker was validated in a cohort of 224 non-alcoholic fatty liver disease patients. In both pilot and validation study, glycomarker score increased in ascending amount of lobular inflammation (single-factor ANOVA, P ≤ 0.001 and P=0.012, respectively). The N-glycan profile of immunoglobulin G in the NASH population confirmed the significantly increased undergalactosylation present in these patients.

CONCLUSION

Our glycomarker specifically recognises liver inflammation in obese individuals which is the main trigger for the development of steatohepatitis and can differentiate between steatosis and NASH.

Inhibition of placental growth factor activity reduces the severity of fibrosis, inflammation, and portal hypertension in cirrhotic mice

Placental growth factor (PlGF) is associated selectively with pathological angiogenesis, and PlGF blockade does not affect the healthy vasculature. Anti-PlGF is therefore currently being clinically evaluated for the treatment of cancer patients. In cirrhosis, hepatic fibrogenesis is accompanied by extensive angiogenesis. In this paper, we evaluated the pathophysiological role of PlGF and the therapeutic potential of anti-PlGF in liver cirrhosis. PlGF was significantly up-regulated in the CCl(4) -induced rodent model of liver cirrhosis as well as in cirrhotic patients. Compared with wild-type animals, cirrhotic PlGF(-/-) mice showed a significant reduction in angiogenesis, arteriogenesis, inflammation, fibrosis, and portal hypertension. Importantly, pharmacological inhibition with anti-PlGF antibodies yielded similar results as genetic loss of PlGF. Notably, PlGF treatment of activated hepatic stellate cells induced sustained extracellular signal-regulated kinase 1/2 phosphorylation, as well as chemotaxis and proliferation, indicating a previously unrecognized profibrogenic role of PlGF.

CONCLUSION

PlGF is a disease-candidate gene in liver cirrhosis, and inhibition of PlGF offers a therapeutic alternative with an attractive safety profile.

Alterations of serum protein N-glycosylation in two mouse models of chronic liver disease are hepatocyte and not B cell driven

N-glycosylation of immunoglobulin G (IgG) has an important impact on the modification of the total serum N-glycome in chronic liver patients. Our aim was to determine the role and magnitude of the alterations in which hepatocytes and B cells are involved in two mouse models of chronic liver disease. Common bile duct ligation (CBDL) and subcutaneous injections with CCl(4) were induced in B cell-deficient and wild-type (WT) mice. IgG depletion was performed with beads covered with protein A/G and the depletions were evaluated by SDS-PAGE and Western blot analysis. N-glycan analysis was performed by improved DSA-FACE technology. Structural analysis of the mouse serum N-glycans was performed by exoglycosidase digests and MALDI-TOF mass spectrometry of permethylated glycans. The alterations seen in B cell-deficient mice closely resembled the alterations in WT mice, in both the CBDL and the CCl(4) models. N-glycan analysis of the IgG fraction in both mouse models revealed different changes compared with humans. Overall, the impact of IgG glycosylation on total serum glycosylation was marginal. Interestingly, the amount of fibrosis present in CBDL B cell-deficient mice was significantly increased compared with CBDL WT mice, whereas the opposite was true for the CCl(4) model as determined by Sirius red staining. However, this had no major effect on the alteration of N-glycosylation of serum proteins. Alterations of total serum N-glycome in mouse models of chronic liver disease are hepatocyte-driven. Undergalactosylation of IgG is not present in mouse models of chronic liver disease.

Impact of elevation of total bilirubin level and etiology of the liver disease on serum N-glycosylation patterns in mice and humans

The GlycoFibroTest and GlycoCirrhoTest are noninvasive alternatives for liver biopsy that can be used as a follow-up tool for fibrosis patients and to diagnose cirrhotic patients, respectively. These tests are based on the altered N-glycosylation of total serum protein. Our aim was to investigate the impact of etiology on the alteration of N-glycosylation and whether other characteristics of liver patients could have an influence on N-glycosylation. In human liver patients, no specific alteration could be found to make a distinction according to etiological factor, although alcoholic patients had a significant higher mean value for the GlycoCirrhoTest. Undergalactosylation did not show a significantly different quantitative alteration in the cirrhotic and noncirrhotic population of all etiologies. Importantly, patients with an elevation of total bilirubin level (>2 mg/dl) had a strong increase of glycans modified with alpha1-6 fucose. The fucosylation index was therefore significantly higher in fibrosis/cirrhosis and hepatocellular carcinoma patients with elevated total bilirubin levels irrespective of etiology. Furthermore, in a multiple linear regression analysis, only markers for cholestasis significantly correlated with the fucosylation index. In mouse models of chronic liver disease, the fucosylation index was uniquely significantly increased in mice that were induced with a common bile duct ligation. Mice that were chronically injected with CCl(4) did not show this increase. Apart from this difference, common changes characteristic to fibrosis development in mice were observed. Finally, mice induced with a partial portal vein ligation did not show biological relevant changes indicating that portal hypertension does not contribute to the alteration of N-glycosylation.

Alteration of protein glycosylation in liver diseases

Chronic liver diseases are a serious health problem worldwide. The current gold standard to assess structural liver damage is through a liver biopsy which has several disadvantages. A non-invasive, simple and non-expensive test to diagnose liver pathology would be highly desirable. Protein glycosylation has drawn the attention of many researchers in the search for an objective feature to achieve this goal. Glycosylation is a posttranslational modification of many secreted proteins and it has been known for decades that structural changes in the glycan structures of serum proteins are an indication for liver damage. The aim of this paper is to give an overview of this altered protein glycosylation in different etiologies of liver fibrosis / cirrhosis and hepatocellular carcinoma. Although individual liver diseases have their own specific markers, the same modifications seem to continuously reappear in all liver diseases: hyperfucosylation, increased branching and a bisecting N-acetylglucosamine. Analysis at mRNA and protein level of the corresponding glycosyltransferases confirm their altered status in liver pathology. The last part of this review deals with some recently developed glycomic techniques that could potentially be used in the diagnosis of liver pathology.

Disaccharidase activities in Belgian children: reference intervals and comparison with non-Belgian Caucasian children

AIM

To establish reference values for disaccharidase activities in Belgian children and to compare enzyme activities with those of non-Belgian Caucasian children.

METHODS

Data from Belgian children who had undergone endoscopic jejunal biopsies (1994-2000) for suspected malabsorption were reviewed. The patients were divided into three groups based on histology: (A) normal (n = 201), (B) moderate changes (n = 58) and (C) (sub)total atrophy (n = 14). The 95% reference limits for disaccharidase activities (U/g protein) were calculated for group A after exclusion of patients with a positive hydrogen breath test, a history of lactose intolerance or coeliac disease (final population: n = 151, 0.1-12 y). Values were compared with those of 34 non-Belgian Caucasian children with normal histology (28 of Mediterranean origin).

RESULTS

The reference limits (90% confidence interval) were 86 (65-111)-423 (366-494) for maltase, 9 (6-12)-91 (78-122) for lactase and 24 (18-30)-155 (120-184) for sucrase. No gender-related differences in enzyme activities were found. Lactase levels showed a slight decrease with increasing age. Disaccharidase activities of children with histologically confirmed mucosal injury were significantly lower than those of children with normal histology: median values for groups A, B and C were 208, 181 and 96, respectively, for maltase, 40, 28 and 7, respectively, for lactase and 69, 54 and 25, respectively, for sucrase. Median disaccharidase activities in biopsies with normal histology were lower in non-Belgian children, the difference being only statistically significant for lactase, 33 versus 40.

CONCLUSION

The reference values for Belgian children are well in line with other reported values from Caucasian children. Although enzyme activities are lower in children with histologically confirmed mucosal damage, they do not allow differentiation between histology groups. Lower lactase values were found in non-Belgian children.

Disaccharidase activities in Belgian children: reference intervals and comparison with non-Belgian Caucasian children

AIM

To establish reference values for disaccharidase activities in Belgian children and to compare enzyme activities with those of non-Belgian Caucasian children.

METHODS

Data from Belgian children who had undergone endoscopic jejunal biopsies (1994-2000) for suspected malabsorption were reviewed. The patients were divided into three groups based on histology: (A) normal (n = 201), (B) moderate changes (n = 58) and (C) (sub)total atrophy (n = 14). The 95% reference limits for disaccharidase activities (U/g protein) were calculated for group A after exclusion of patients with a positive hydrogen breath test, a history of lactose intolerance or coeliac disease (final population: n = 151, 0.1-12 y). Values were compared with those of 34 non-Belgian Caucasian children with normal histology (28 of Mediterranean origin).

RESULTS

The reference limits (90% confidence interval) were 86 (65-111)-423 (366-494) for maltase, 9 (6-12)-91 (78-122) for lactase and 24 (18-30)-155 (120-184) for sucrase. No gender-related differences in enzyme activities were found. Lactase levels showed a slight decrease with increasing age. Disaccharidase activities of children with histologically confirmed mucosal injury were significantly lower than those of children with normal histology: median values for groups A, B and C were 208, 181 and 96, respectively, for maltase, 40, 28 and 7, respectively, for lactase and 69, 54 and 25, respectively, for sucrase. Median disaccharidase activities in biopsies with normal histology were lower in non-Belgian children, the difference being only statistically significant for lactase, 33 versus 40.

CONCLUSION

The reference values for Belgian children are well in line with other reported values from Caucasian children. Although enzyme activities are lower in children with histologically confirmed mucosal damage, they do not allow differentiation between histology groups. Lower lactase values were found in non-Belgian children.

Cobas Mira S endpoint enzymatic assay for plasma formate

In methanol intoxication, increased levels of the metabolite formate are associated with metabolic acidosis and an increased risk for ocular and neurological dysfunction. A simple method for plasma formate measurement by adaptation of a manual enzymatic assay to a Cobas Mira S analyzer is presented. Six microliters of sample is incubated for 5 min with buffer containing nicotinamide-adenine dinucleotide. Fifteen microliters of a suspension of formate dehydrogenase is then added. Absorbance at 340 nm is measured every 25 s. The NADH produced when formate is oxidized is stoichiometric to the amount of formate. The method is sensitive, reproducible, and specific and has a broad measurement range. The frozen reagents are stable for at least six months, so the described method can be applied to irregular and semi-urgent requests. A recent case is reported.