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OBJECTIVE Ten kilohertz spinal cord stimulation (SCS) is usually initiated in a single-bipolar configuration over the radiological reference point T9/T10 intervertebral disc space for neuropathic back and leg pain. Cascade is a duty-cycled, multi-bipolar contact configuration across an entire eight-contact lead. Potential advantages by using a broader area of SCS coverage include mitigation against minor lead migration and a reduction in the need for reprogramming. We report here the results of a retrospective case series of 114 patients using Cascade. MATERIALS AND METHODS Retrospective data were collected over two years. We selected patients with neuropathic back with or without/leg pain who had a trial of SCS. Pain assessments using Numerical Rating Scales (NRS) and Patient Global Impression of Change (PGIC) scores were collected at baseline, six months, and last follow-up beyond 12 months (mean 15.1 months). Patients were programmed with 10 kHz SCS using Cascade during the trial, which was continued unless reporting inadequate pain relief. Morbidity and deviations from Cascade programming were also obtained. RESULTS At six months, 87 of 97 (90.6%) patients with active devices were using Cascade and 58 of 72 (81%) patients at the last follow-up >12 months. There was a significant reduction in back NRS (8.3 vs. 3.9 [p 12 months back (8.3 vs. 3.95 [p

Spinal cord stimulation (SCS) is an established therapy for chronic neuropathic pain and most frequently utilised for Failed Back Surgery Syndrome (FBSS). BurstDR™ also known as DeRidder Burst-SCS, a novel waveform, has demonstrated superiority to conventional tonic stimulation of the thoracic spine in FBSS. There are case reports of an improvement in multidimensional pain outcomes using DeRidder Burst-SCS in the cervical spine for chronic neck and cervical radicular pain. The safety and efficacy of cervical DeRidder Burst-SCS stimulation still however remain undetermined. This is a prospective, multicentre feasibility trial evaluating the safety and therapeutic efficacy of DeRidder Burst-SCS stimulation for the treatment of chronic intractable neck pain with or without radiation to the arm, shoulder, and upper back. After baseline evaluation, subjects will undergo an SCS trial using the Abbott Invisible Trial system according to standard clinical procedures. During the trial phase, SCS leads will be implanted in the cervical epidural space. At the end of the SCS trial, subjects experiencing at least 50% pain relief will be considered for permanent implant. Pain intensity, medication usage, and other multidimensional pain outcomes will be collected. The timing of these will be at baseline, end of the SCS trial and at 3-, 6-, and 12-month visits. Incidence of adverse events will be collected throughout the study duration. The results of this feasibility study will validate the efficacy and safety of DeRidder Burst-SCS stimulation in the cervical spine. The results obtained in this study will potentially be used to generate a level 1 evidence-based study with formal statistical hypotheses testing. www.clinicaltrials.gov Identifier: NCT03159169.

IntroductionThe publication of explant rates has established risk factors and a definitive objective outcome of failure for spinal cord stimulation (SCS) treating neuropathic pain. We present a UK study analyzing explants of electrical neuromodulation devices for different conditions over 11 years in a single center specializing in neuromodulation.MethodsA retrospective analysis was performed using a departmental database between 2008 and 2019. Explants were analyzed according to condition, mode of stimulation and other demographics using logistic regression and Kaplan-Meier graphs with log-rank (Mantel-Cox) test.ResultsOut of a total of 1177 patients, the explant rate was 17.8% at 5 years and 25.2% at 10 years. Loss of efficacy was the most frequent reason for explant 119/181 (65%). Multivariant regression analysis indicated patients with back pain without prior surgery had a reduced risk of explant (p=0.03). Patients with SCS systems that had 10 kHz, options of multiple waveforms, and rechargeable batteries also had a decreased risk of explant (pConclusionThese data contribute to a growing list of explant data in the scientific literature and give indications of what factors contribute to long-term utilization of electrical neuromodulation devices.

Amitriptyline is prescribed for treating the symptoms of neuroinflammatory disorders including neuropathic pain and fibromyalgia. As amitriptyline has evidence of modulating the neuroimmune interface; the effects of amitriptyline treatment on T-cell phenotype and function were examined in vitro. Peripheral blood mononuclear cells(PBMCs) were isolated and treated with amitriptyline, nortriptyline and a combination of both drugs. Toxicity for T-cells was assessed by Annexin V/Propidium Iodide staining. Activation status and cytokine expression by T-cells post treatment was assessed by flow cytometry. The levels of secreted cytokines, chemokines and neurotrophins were measured by ELISA in the supernatants. There was no significant increase in T-cell death following 24 or 48 h compared to controls. There were significantly lower frequencies of CD8+ T-cells after treatment with amitriptyline, nortriptyline and a combination of both compared to a Vehicle Control(VC)(p

Introduction Chronic neuropathic low back pain (CNLBP) is a debilitating condition in which established medical treatments seldom alleviate symptoms. Evidence demonstrates that high-frequency 10 kHz spinal cord stimulation (SCS) reduces pain and improves health-related quality of life in patients with failed back surgery syndrome (FBSS), but evidence of this effect is limited in individuals with CNLBP who have not had surgery. The aim of this multicentre randomised trial is to assess the clinical and cost-effectiveness of 10 kHz SCS for this population. Methods This is a multicentre, double-blind, randomised, sham-controlled trial with a parallel economic evaluation. A total of 96 patients with CNLBP who have not had spinal surgery will be implanted with an epidural lead and a sham lead outside the epidural space without a screening trial. Patients will be randomised 1:1 to 10 kHz SCS plus usual care (intervention group) or to sham 10 kHz SCS plus usual care (control group) after receiving the full implant. The SCS devices will be programmed identically using a cathodal cascade. Participants will use their handheld programmer to alter the intensity of the stimulation as per routine practice. The primary outcome will be a 7-day daily pain diary. Secondary outcomes include the Oswestry Disability Index, complications, EQ-5D-5 L, and health and social care costs. Outcomes will be assessed at baseline (pre-randomisation) and at 1 month, 3 months and 6 months after device activation. The primary analyses will compare primary and secondary outcomes between groups at 6 months, while adjusting for baseline outcome scores. Incremental cost per quality-adjusted life year (QALY) will be calculated at 6 months and over the lifetime of the patient. Discussion The outcomes of this trial will inform clinical practice and healthcare policy on the role of high-frequency 10 kHz SCS for use in patients with CNLBP who have not had surgery. Trial registration Clinicaltrials.gov, NCT03470766. Registered on 20 March 2018. Disclaimer The views expressed here are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The NIHR had no role in the study design, writing of the manuscript or the decision to submit for publication. Roles and Responsibilities AK, SP, DP, SW, RST, AC, SE, LM, RD and JF all contributed to the trial design and to securing trial funding. AK, JR, SP, DP, and SE are involved in the recruitment, the intervention and the follow-up. SW will perform data collection and analysis. RST will be responsible for the statistical analysis, and RD will be responsible for the health economic analysis. All authors read and approved the final manuscript.

To the Editor We would like to thank the authors for their response to our article and appreciate the opportunity to discuss our study further.[1][1] We have addressed the issues raised in a point by point response. Only n=2 (2/1177, 0.2%) of our electrical neuromodulation devices were explanted

Introduction Patients with neuropathic pain have altered proteomic and neuropeptide constituents in cerebrospinal fluid (CSF) compared to controls. Tonic spinal cord stimulation (SCS) has demonstrated differential expression of neuropeptides in CSF before and after treatment suggesting potential mechanisms of action. Burst-SCS is an evidence-based paraesthesia free waveform utilised for neuropathic pain with a potentially different mechanistic action to tonic SCS. This study examines the dynamic biological changes of CSF at a cellular and proteome level after Burst-SCS. Methods Patients with neuropathic pain selected for SCS had CSF sampled prior to implant of SCS and following 8 weeks of continuous Burst-SCS. Baseline and 8-week pain scores with demographics were recorded. T cell frequencies were analysed by flow cytometry, proteome analysis was performed using mass spectrometry and secreted cytokines, chemokines and neurotrophins were measured by enzyme-linked immunosorbent assay (ELISA). Results 4 patients (2 females, 2 males) with a mean age of 51 years (+/-SEM 2.74, SD 5.48) achieved a reduction in pain of >50% following 8 weeks of Burst-SCS. Analysis of the CSF proteome indicated a significant alteration in protein expression most related to synapse assembly and immune regulators. There was significantly lower expression of the proteins: growth hormone A1 (PRL), somatostatin (SST), nucleobindin-2 (NUCB2), Calbindin (CALB1), acyl-CoA binding protein (DBI), proSAAS (PCSK1N), endothelin-3 (END3) and cholecystokinin (CCK) after Burst-SCS. The concentrations of secreted chemokines and cytokines and the frequencies of T cells were not significantly changed following Burst-SCS. Conclusion This study characterised the alteration in the CSF proteome in response to burst SCS in vivo. Functional analysis indicated that the alterations in the CSF proteome is predominately linked to synapse assembly and immune effectors. Individual protein analysis also suggests potential supraspinal mechanisms.

Rigid bronchoscopy may be used to relieve acute airway obstruction following induction of anaesthesia and is a recommended option for management of the difficult airway. The ability of anaesthetists to perform rigid bronchoscopy has not been reported. We sought to explore the acquisition of procedural skill in rigid bronchoscopy by anaesthesiologists in a manikin. In a prospective interventional study, participants were asked to perform 40 rigid bronchoscopies in a TruCorp AirSim Advance airway manikin, configured to a randomised sequence of easy or difficult laryngoscopic grades to which the participants were blinded. The primary outcome was stabilisation (the attempt after which no further reduction in procedural time occurred). Dental injury and oesophageal intubation were also recorded. Forty anaesthesiologists and 40 unskilled controls (without laryngoscopic skills) participated. In the easy model, stabilisation occurred at attempt 8 in the anaesthesiology group and 10 in the unskilled controls. In the difficult model, stabilisation occurred at attempt 10 in both groups. Dental injury was less common in the anaesthesiology group. The proportion of participants achieving procedural competency did not differ between groups in either the easy (35/40 vs. 30/40) or difficult model (32/40 vs. 25/40). This study shows that the technical skill of rigid bronchoscopy can be acquired within 10 repetitions in a manikin model. As procedural competence and complication frequency vary with the laryngoscopic grade of the model, both easy and difficult configurations should be used for training. Advanced laryngoscopic skills are not required prior to training in this technique.

Background The cricothyroid membrane (CTM) is the recommended site of access to the airway during cricothyrotomy to provide emergency oxygenation. We sought to compare the ability of physicians to correctly identify the CTM in male and female patients. Methods In a prospective observational study, anaesthetists were asked to locate the CTM by palpation which was then identified using ultrasound and the distance between the actual and estimated margin of the CTM was measured. Participants assessed the ease of CTM palpation using a visual analog scale. In a second series, the angulation of the posterior junction of the thyroid laminae was measured using ultrasound. Results 23 anaesthetists and 44 subjects participated. A total of 36 assessments were carried out in each gender. Incorrect identification of the CTM was more common in females (29/36 vs. 11/36, P

Background The recent interest in targeting the dorsal root ganglion (DRG) has led to the development of new techniques of electrode placement. In this article, we describe a new "Transgrade" approach to the DRG, accessing the contralateral interlaminar space and steering the lead out the opposite foramen. Objectives The purpose of this study was to evaluate the Transgrade technique to the DRG in the management of focal neuropathic pain, predominately complex regional pain syndrome in terms of efficacy and safety. Study design A retrospective, observational review of all patients selected for DRG stimulation using the Transgrade technique to the DRG. Setting Pain Management and Neuromodulation Centre, Guys and St. Thomas NHS Foundation Trust, London, United Kingdom. Methods Data were taken from a hospital password-protected database. All patients were contacted by telephone for Numeric Rating Scale (NRS-11) score, Patient Global Impression of Change (PGIC) score, and complications. A patient responder was defined as having a PGIC score of 6 or 7, and a 2-point reduction from baseline NRS-11. Results A total of 39 patients (46% women) with a mean age of 46 years (± 2) underwent a trial of DRG stimulation that resulted in an implantation rate of 82% (32 of 39). The responder rates, according to NRS-11 and PGIC results, were 87% (28 of 32) at 6 weeks and 66% (21 of 32) at a mean of 18 months (± 1.8) follow-up. Pocket pain was the most common complication, occurring in 7 of 32 (22%) patients, and the lead migration rate was 3 out of 57 leads placed (5.2%). A burst protocol was the favored method of stimulation in the majority of patients, 25 of 32 (78%). Limitations Retrospective nature of design, small sample size. Conclusions The Transgrade technique of placing DRG leads offers an alternative method that is safe and effective. New methods of stimulation to the DRG offer more choice and potentially better efficacy for patients with chronic neuropathic pain. Key words Neuromodulation, dorsal root ganglion, neuropathic pain, complex regional pain syndrome, spinal cord stimulation, chronic pain, implantable neurostimulators, spinal nerve root stimulation.