Long-term quality of life improvement for chronic intractable back and leg pain patients using spinal cord stimulation: 12-month results from the SENZA-RCT.

PURPOSE: Chronic axial low-back pain is a debilitating disorder that impacts all aspects of an afflicted individual's life. Effective, durable treatments have historically been elusive. Interventional therapies, such as spinal cord stimulation (SCS), have shown limited efficacy at best. Recently, a novel treatment, 10 kHz SCS, has demonstrated superior pain relief compared with traditional SCS in a randomized controlled trial (RCT). In this manuscript, we report on the long-term improvements in quality of life (QoL) outcomes for subjects enrolled in this study. METHODS: A prospective, multicenter, randomized controlled trial (SENZA-RCT) was conducted. Patients with both chronic back and leg pain were enrolled and randomized (1:1) into 10 kHz SCS or traditional SCS treatment groups. A total of 171 subjects received a permanent SCS device implant. QoL and functionality measures were collected up to 12 months. The device remote control utilization, which is an indication of patient interaction with the device for adjustments, was collected at 24-month post-implantation. RESULTS: At 12 months, a higher proportion of 10 kHz SCS subjects had marked improvement of their disability (Oswestry Disability Index) to a "moderate" or "minimal" impact on their daily function versus the control group. The subjects also reported better improvement in the Global Assessment of Functioning, Clinician Global Impression of Change, Pittsburgh Sleep Quality Index, and short-form McGill Pain Questionnaire, compared to traditional SCS subjects. The 10 kHz SCS subjects also reported far higher rates of both driving and sleeping with their device turned on, as well as reduced reliance on their programmers to adjust therapy settings. CONCLUSIONS: In addition to superior pain relief, 10 kHz SCS provides long-term improvements in quality of life and functionality for subjects with chronic low-back and leg pain. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01609972).

The appropriate use of neurostimulation: avoidance and treatment of complications of neurostimulation therapies for the treatment of chronic pain. Neuromodulation Appropriateness Consensus Committee.

INTRODUCTION: The International Neuromodulation Society (INS) has determined that there is a need for guidance regarding safety and risk reduction for implantable neurostimulation devices. The INS convened an international committee of experts in the field to explore the evidence and clinical experience regarding safety, risks, and steps to risk reduction to improve outcomes. METHODS: The Neuromodulation Appropriateness Consensus Committee (NACC) reviewed the world literature in English by searching MEDLINE, PubMed, and Google Scholar to evaluate the evidence for ways to reduce risks of neurostimulation therapies. This evidence, obtained from the relevant literature, and clinical experience obtained from the convened consensus panel were used to make final recommendations on improving safety and reducing risks. RESULTS: The NACC determined that the ability to reduce risk associated with the use of neurostimulation devices is a valuable goal and possible with best practice. The NACC has recommended several practice modifications that will lead to improved care. The NACC also sets out the minimum training standards necessary to become an implanting physician. CONCLUSIONS: The NACC has identified the possibility of improving patient care and safety through practice modification. We recommend that all implanting physicians review this guidance and consider adapting their practice accordingly.

Pediatric Population Management Classification for Children with Medical Complexity.

Improving the overall care of children with medical complexity (CMC) is often beset by challenges in proactively identifying the population most in need of clinical management and quality improvement. The objective of the current study was to create a system to better capture longitudinal risk for sustained and elevated utilization across time using real-time electronic health record (EHR) data. A new Pediatric Population Management Classification (PPMC), drawn from visit diagnoses and continuity problem lists within the EHR of a tristate health system, was compared with an existing complex chronic conditions (CCC) system for agreement (with weighted κ) on identifying CCMC, as well as persistence of elevated charges and utilization from 2016 to 2019. Agreement of assignment PPMC was lower among primary care provider (PCP) populations than among other children traversing the health system for specialty or hospital services only (weighted κ 62% for PCP vs. 82% for non-PCP). The PPMC classification scheme, displaying greater precision in identifying CMC with persistently high utilization and charges for those who receive primary care within a large integrated health network, may offer a more pragmatic approach to selecting children with CMC for longitudinal care management.

Long-term efficacy of high-frequency (10 kHz) spinal cord stimulation for the treatment of painful diabetic neuropathy: 24-Month results of a randomized controlled trial.

AIMS: To evaluate the long-term efficacy of high-frequency (10 kHz) spinal cord stimulation (SCS) for treating refractory painful diabetic neuropathy (PDN). METHODS: The SENZA-PDN study was a prospective, multicenter, randomized controlled trial that compared conventional medical management (CMM) alone with 10 kHz SCS plus CMM (10 kHz SCS+CMM) in 216 patients with refractory PDN. After 6 months, participants with insufficient pain relief could cross over to the other treatment. In total, 142 patients with a 10 kHz SCS system were followed for 24 months, including 84 initial 10 kHz SCS+CMM recipients and 58 crossovers from CMM alone. Assessments included pain intensity, health-related quality of life (HRQoL), sleep, and neurological function. Investigators assessed neurological function via sensory, reflex, and motor tests. They identified a clinically meaningful improvement relative to the baseline assessment if there was a significant persistent improvement in neurological function that impacted the participant's well-being and was attributable to a neurological finding. RESULTS: At 24 months, 10 kHz SCS reduced pain by a mean of 79.9% compared to baseline, with 90.1% of participants experiencing ≥50% pain relief. Participants had significantly improved HRQoL and sleep, and 65.7% demonstrated clinically meaningful neurological improvement. Five (3.2%) SCS systems were explanted due to infection. CONCLUSIONS: Over 24 months, 10 kHz SCS provided durable pain relief and significant improvements in HRQoL and sleep. Furthermore, the majority of participants demonstrated neurological improvement. These long-term data support 10 kHz SCS as a safe and highly effective therapy for PDN. TRIAL REGISTRATION: ClincalTrials.gov Identifier, NCT03228420.

A Real-World Analysis of High-Frequency 10 kHz Spinal Cord Stimulation for the Treatment of Painful Diabetic Peripheral Neuropathy.

BACKGROUND: Diabetes is one of the most prevalent chronic health conditions and diabetic neuropathy one of its most prevalent and debilitating complications. While there are treatments available for painful diabetic peripheral neuropathy (pDPN), their effectiveness is limited. METHOD: This retrospective, multi-center, real-world review assessed pain relief and functional improvements for consecutive patients with diabetic neuropathy aged ≥18 years of age who were permanently implanted with a high-frequency (10 kHz) spinal cord stimulation (SCS) device. Available data were extracted from a commercial database. RESULTS: In total 89 patients consented to being included in the analysis. Sixty-one percent (54/89) of participants were male and the average age was 64.4 years (SD = 9.1). Most patients (78.7%, 70/89) identified pain primarily in their feet or legs bilaterally. At the last assessment, 79.5% (58/73) of patients were treatment responders, defined as having at least 50% patient-reported pain relief from baseline. The average time of follow-up was 21.8 months (range: 4.3 to 46.3 months). A majority of patients reported improvements in sleep and overall function relative to their baseline. CONCLUSIONS: This real-world study in typical clinical practices found 10 kHz SCS provided meaningful pain relief for a substantial proportion of patients refractory to current pDPN management, similar to published literature. This patient population has tremendous unmet needs and this study helps demonstrate the potential for 10 kHz SCS to provide an alternative pain management approach.

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.

Effect of High-frequency (10-kHz) Spinal Cord Stimulation in Patients With Painful Diabetic Neuropathy: A Randomized Clinical Trial.

Importance: Many patients with diabetic peripheral neuropathy experience chronic pain and inadequate relief despite best available medical treatments. Objective: To determine whether 10-kHz spinal cord stimulation (SCS) improves outcomes for patients with refractory painful diabetic neuropathy (PDN). Design, Setting, and Participants: The prospective, multicenter, open-label SENZA-PDN randomized clinical trial compared conventional medical management (CMM) with 10-kHz SCS plus CMM. Participants with PDN for 1 year or more refractory to gabapentinoids and at least 1 other analgesic class, lower limb pain intensity of 5 cm or more on a 10-cm visual analogue scale (VAS), body mass index (calculated as weight in kilograms divided by height in meters squared) of 45 or less, hemoglobin A1c (HbA1c) of 10% or less, daily morphine equivalents of 120 mg or less, and medically appropriate for the procedure were recruited from clinic patient populations and digital advertising. Participants were enrolled from multiple sites across the US, including academic centers and community pain clinics, between August 2017 and August 2019 with 6-month follow-up and optional crossover at 6 months. Screening 430 patients resulted in 214 who were excluded or declined participation and 216 who were randomized. At 6-month follow-up, 187 patients were evaluated. Interventions: Implanted medical device delivering 10-kHz SCS. Main Outcomes and Measures: The prespecified primary end point was percentage of participants with 50% pain relief or more on VAS without worsening of baseline neurological deficits at 3 months. Secondary end points were tested hierarchically, as prespecified in the analysis plan. Measures included pain VAS, neurological examination, health-related quality of life (EuroQol Five-Dimension questionnaire), and HbA1c over 6 months. Results: Of 216 randomized patients, 136 (63.0%) were male, and the mean (SD) age was 60.8 (10.7) years. Additionally, the median (interquartile range) duration of diabetes and peripheral neuropathy were 10.9 (6.3-16.4) years and 5.6 (3.0-10.1) years, respectively. The primary end point assessed in the intention-to-treat population was met by 5 of 94 patients in the CMM group (5%) and 75 of 95 patients in the 10-kHz SCS plus CMM group (79%; difference, 73.6%; 95% CI, 64.2-83.0; P < .001). Infections requiring device explant occurred in 2 patients in the 10-kHz SCS plus CMM group (2%). For the CMM group, the mean pain VAS score was 7.0 cm (95% CI, 6.7-7.3) at baseline and 6.9 cm (95% CI, 6.5-7.3) at 6 months. For the 10-kHz SCS plus CMM group, the mean pain VAS score was 7.6 cm (95% CI, 7.3-7.9) at baseline and 1.7 cm (95% CI, 1.3-2.1) at 6 months. Investigators observed neurological examination improvements for 3 of 92 patients in the CMM group (3%) and 52 of 84 in the 10-kHz SCS plus CMM group (62%) at 6 months (difference, 58.6%; 95% CI, 47.6-69.6; P < .001). Conclusions and Relevance: Substantial pain relief and improved health-related quality of life sustained over 6 months demonstrates 10-kHz SCS can safely and effectively treat patients with refractory PDN. Trial Registration: ClincalTrials.gov Identifier: NCT03228420.

Trafficking of vesicular neurotransmitter transporters.

Vesicular neurotransmitter transporters are required for the storage of all classical and amino acid neurotransmitters in secretory vesicles. Transporter expression can influence neurotransmitter storage and release, and trafficking targets the transporters to different types of secretory vesicles. Vesicular transporters traffic to synaptic vesicles (SVs) as well as large dense core vesicles and are recycled to SVs at the nerve terminal. Some of the intrinsic signals for these trafficking events have been defined and include a dileucine motif present in multiple transporter subtypes, an acidic cluster in the neural isoform of the vesicular monoamine transporter (VMAT) 2 and a polyproline motif in the vesicular glutamate transporter (VGLUT) 1. The sorting of VMAT2 and the vesicular acetylcholine transporter to secretory vesicles is regulated by phosphorylation. In addition, VGLUT1 uses alternative endocytic pathways for recycling back to SVs following exocytosis. Regulation of these sorting events has the potential to influence synaptic transmission and behavior.

The Drosophila vesicular monoamine transporter reduces pesticide-induced loss of dopaminergic neurons.

Dopamine is cytotoxic and may play a role in the development of Parkinson's disease. However, its interaction with environmental risk factors such as pesticides remains poorly understood. The vesicular monoamine transporter (VMAT) regulates intracellular dopamine content, and we have tested the neuroprotective effects of VMAT in vivo using the model organism Drosophila melanogaster. We find that Drosophila VMAT (dVMAT) mutants contain fewer dopaminergic neurons than wild type, consistent with a developmental effect, and that dopaminergic cell loss in the mutant is exacerbated by the pesticides rotenone and paraquat. Overexpression of DVMAT protein does not increase the survival of animals exposed to rotenone, but blocks the loss of dopaminergic neurons caused by this pesticide. These results are the first to demonstrate an interaction between a VMAT and pesticides in vivo, and provide an important model to investigate the mechanisms by which pesticides and cellular DA may interact to kill dopaminergic cells.

Identification and Management of Adolescent Depression in a Large Pediatric Care Network.

OBJECTIVE: Primary care has been promoted as a setting to identify and manage adolescent depression. This study examined primary care-based adolescent depression identification and follow-up care when elevated symptoms were identified. METHODS: Data came from a large pediatric care network with an organizational recommendation to screen for depression at age 16 well-visits using an electronic health record (EHR)-integrated standardized measure. Analyses examined rates of screening and elevated symptoms, pediatricians' initial responses to elevated scores, and types of follow-up care received over 1 year using retrospective EHR data extraction and manual chart reviews. RESULTS: Across program sites, 76.3% (n = 6981) of patients attending their age 16 well-visits were screened. About one-quarter had an elevated score (19.2% mild and 6.7% moderate-to-severe), many of whom received active follow-up on their well-visit date. Over 1 year, three-fourths of patients with scores in the moderate-to-severe range and 40.0% of patients with scores in the mild range received follow-up care (e.g., antidepressant prescriptions) as per EHR extraction. Follow-up rates were higher as per manual chart reviews. CONCLUSION: Routine adolescent depression screening is feasible across diverse primary care sites. Most patients with elevated scores were not already receiving behavioral health services, suggesting screening identified previously undetected concerns. In turn, many adolescents with elevated scores initiated treatment after screening, which indicates providing screen results at the point of care may facilitate pediatrician actions. Still, gaps in follow-up care demonstrate the need for greater investment in primary care-based behavioral health services to support high-quality treatment and ultimately decrease the burden of adolescent depression.

High-frequency spinal cord stimulation at 10 kHz for the treatment of painful diabetic neuropathy: design of a multicenter, randomized controlled trial (SENZA-PDN).

BACKGROUND: Painful diabetic neuropathy (PDN), a debilitating and progressive chronic pain condition that significantly impacts quality of life, is one of the common complications seen with long-standing diabetes mellitus. Neither pharmacological treatments nor low-frequency spinal cord stimulation (SCS) has provided significant and long-term pain relief for patients with PDN. This study aims to document the value of 10-kHz SCS in addition to conventional medical management (CMM) compared with CMM alone in patients with refractory PDN. METHODS: In a prospective, multicenter, randomized controlled trial (SENZA-PDN), 216 subjects with PDN will be assigned 1:1 to receive 10-kHz SCS combined with CMM or CMM alone after appropriate institutional review board approvals and followed for 24 months. Key inclusion criteria include (1) symptoms of PDN for at least 12 months, (2) average pain intensity of at least 5 cm-on a 0- to 10-cm visual analog scale (VAS)-in the lower limbs, and (3) an appropriate candidate for SCS. Key exclusion criteria include (1) large or gangrenous ulcers or (2) average pain intensity of at least 3 cm on VAS in the upper limbs or both. Along with pain VAS, neurological assessments, health-related quality of life, sleep quality, and patient satisfaction will be captured. The primary endpoint comparing responder rates (≥50% pain relief) and safety rates between the treatment groups will be assessed at 3 months. Several secondary endpoints will also be reported on. DISCUSSION: Enrollment commenced in 2017 and was completed in 2019. This study will help to determine whether 10-kHz SCS improves clinical outcomes and health-related quality of life and is a cost-effective treatment for PDN that is refractory to CMM. TRIAL REGISTRATION: ClincalTrials.gov identifier: NCT03228420 (registered 24 July 2017).

Increased expression of the Drosophila vesicular glutamate transporter leads to excess glutamate release and a compensatory decrease in quantal content.

Quantal size is a fundamental parameter controlling the strength of synaptic transmission. The transmitter content of synaptic vesicles is one mechanism that can affect the physiological response to the release of a single vesicle. At glutamatergic synapses, vesicular glutamate transporters (VGLUTs) are responsible for filling synaptic vesicles with glutamate. To investigate how VGLUT expression can regulate synaptic strength in vivo, we have identified the Drosophila vesicular glutamate transporter, which we name DVGLUT. DVGLUT mRNA is expressed in glutamatergic motoneurons and a large number of interneurons in the Drosophila CNS. DVGLUT protein resides on synaptic vesicles and localizes to the presynaptic terminals of all known glutamatergic neuromuscular junctions as well as to synapses throughout the CNS neuropil. Increasing the expression of DVGLUT in motoneurons leads to an increase in quantal size that is accompanied by an increase in synaptic vesicle volume. At synapses confronted with increased glutamate release from each vesicle, there is a compensatory decrease in the number of synaptic vesicles released that maintains normal levels of synaptic excitation. These results demonstrate that (1) expression of DVGLUT determines the size and glutamate content of synaptic vesicles and (2) homeostatic mechanisms exist to attenuate the excitatory effects of excess glutamate release.

Epidural hematomas after removal of percutaneous spinal cord stimulator trial leads: two case reports.

OBJECTIVE: We report 2 cases of spinal epidural hematoma formation after the removal of percutaneous spinal cord stimulator trial leads and discuss the possible etiologies of these complications. CASE REPORT: Two patients developed spinal epidural hematomas shortly after removal of their percutaneous trial leads and required multilevel laminectomies for evacuation of the hematoma. Patient 1 reported taking aspirin the morning that his leads were pulled, whereas patient 2 had not taken aspirin in the 7 days before commencing his trial. There were 2 days between identification and evacuation of patient 1's hematoma, and he did not fully recover from the injury to his spinal cord. Patient 2 underwent surgery immediately with complete resolution of his symptoms. CONCLUSIONS: Currently, the neuromodulation community ascribes to the American Society of Regional Anesthesia and Pain Medicine guidelines, which state that nonsteroidal anti-inflammatory drugs do not significantly increase the risk for epidural hematoma with neuraxial anesthesia and, therefore, there is no need to discontinue these drugs before epidural or spinal anesthesia. We suggest that these guidelines may not be appropriate for neuromodulatory techniques that likely subject the surrounding vasculature to more trauma than neuraxial anesthesia. We recommend discontinuing nonsteroidal anti-inflammatory drugs, particularly aspirin, before neuromodulation procedures. Further investigation will establish a timeframe for holding these drugs to optimize patient safety.

A putative vesicular transporter expressed in Drosophila mushroom bodies that mediates sexual behavior may define a neurotransmitter system.

Vesicular transporters are required for the storage of all classical and amino acid neurotransmitters in synaptic vesicles. Some neurons lack known vesicular transporters, suggesting additional neurotransmitter systems remain unidentified. Insect mushroom bodies (MBs) are critical for several behaviors, including learning, but the neurotransmitters released by the intrinsic Kenyon cells (KCs) remain unknown. Likewise, KCs do not express a known vesicular transporter. We report the identification of a novel Drosophila gene portabella (prt) that is structurally similar to known vesicular transporters. Both larval and adult brains express PRT in the KCs of the MBs. Additional PRT cells project to the central complex and optic ganglia. prt mutation causes an olfactory learning deficit and an unusual defect in the male's position during copulation that is rescued by expression in KCs. Because prt is expressed in neurons that lack other known vesicular transporters or neurotransmitters, it may define a previously unknown neurotransmitter system responsible for sexual behavior and a component of olfactory learning.

The Drosophila pigmentation gene pink (p) encodes a homologue of human Hermansky-Pudlak syndrome 5 (HPS5).

Lysosome-related organelles comprise a group of specialized intracellular compartments that include melanosomes and platelet dense granules (in mammals) and eye pigment granules (in insects). In humans, the biogenesis of these organelles is defective in genetic disorders collectively known as Hermansky-Pudlak syndrome (HPS). Patients with HPS-2, and two murine HPS models, carry mutations in genes encoding subunits of adaptor protein (AP)-3. Other genes mutated in rodent models include those encoding VPS33A and Rab38. Orthologs of all of these genes in Drosophila melanogaster belong to the 'granule group' of eye pigmentation genes. Other genes associated with HPS encode subunits of three complexes of unknown function, named biogenesis of lysosome-related organelles complex (BLOC)-1, -2 and -3, for which the Drosophila counterparts had not been characterized. Here, we report that the gene encoding the Drosophila ortholog of the HPS5 subunit of BLOC-2 is identical to the granule group gene pink (p), which was first studied in 1910 but had not been identified at the molecular level. The phenotype of pink mutants was exacerbated by mutations in AP-3 subunits or in the orthologs of VPS33A and Rab38. These results validate D. melanogaster as a genetic model to study the function of the BLOCs.