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Introduction The evidence for spinal cord stimulation (SCS) has been criticized for the absence of blinded, parallel randomized controlled trials (RCTs) and limited evaluations of the long-term effects of SCS in RCTs. The aim of this study was to determine whether evoked compound action potential (ECAP)-controlled, closed-loop SCS (CL-SCS) is associated with better outcomes when compared with fixed-output, open-loop SCS (OL-SCS) 36 months following implant. Methods The EVOKE study was a multicenter, participant-blinded, investigator-blinded, and outcome assessor-blinded, randomized, controlled, parallel-arm clinical trial that compared ECAP-controlled CL-SCS with fixed-output OL-SCS. Participants with chronic, intractable back and leg pain refractory to conservative therapy were enrolled between January 2017 and February 2018, with follow-up through 36 months. The primary outcome was a reduction of at least 50% in overall back and leg pain. Holistic treatment response, a composite outcome including pain intensity, physical and emotional functioning, sleep, and health-related quality of life, and objective neural activation was also assessed. Results At 36 months, more CL-SCS than OL-SCS participants reported ≥50% reduction (CL-SCS= 77.6%, OL-SCS= 49.3%; difference: 28.4%, 95% CI 12.8% to 43.9%, p<0.001) and ≥80% reduction (CL-SCS= 49.3%, OL-SCS= 31.3%; difference: 17.9, 95% CI 1.6% to 34.2%, p=0.032) in overall back and leg pain intensity. Clinically meaningful improvements from baseline were observed at 36 months in both CL-SCS and OL-SCS groups in all other patient-reported outcomes with greater levels of improvement with CL-SCS. A greater proportion of patients with CL-SCS were holistic treatment responders at 36-month follow-up (44.8% vs 28.4%), with a greater cumulative responder score for CL-SCS patients. Greater neural activation and accuracy were observed with CL-SCS. There were no differences between CL-SCS and OL-SCS groups in adverse events. No explants due to loss of efficacy were observed in the CL-SCS group. Conclusion This long-term evaluation with objective measurement of SCS therapy demonstrated that ECAP-controlled CL-SCS resulted in sustained, durable pain relief and superior holistic treatment response through 36 months. Greater neural activation and increased accuracy of therapy delivery were observed with ECAP-controlled CL-SCS than OL-SCS. [ABSTRACT FROM AUTHOR]

Introduction Chronic pain patients may experience impairments in multiple health-related domains. The design and interpretation of clinical trials of chronic pain interventions, however, remains primarily focused on treatment effects on pain intensity. This study investigates a novel, multidimensional holistic treatment response to evoked compound action potential-controlled closed-loop versus open-loop spinal cord stimulation as well as the degree of neural activation that produced that treatment response. Methods Outcome data for pain intensity, physical function, health-related quality of life, sleep quality and emotional function were derived from individual patient level data from the EVOKE multicenter, participant, investigator, and outcome assessor-blinded, parallel-arm randomized controlled trial with 24 month follow-up. Evaluation of holistic treatment response considered whether the baseline score was worse than normative values and whether minimal clinical important differences were reached in each of the domains that were impaired at baseline. A cumulative responder score was calculated to reflect the total minimal clinical important differences accumulated across all domains. Objective neurophysiological data, including spinal cord activation were measured. Results Patients were randomized to closed-loop (n=67) or open- loop (n=67). A greater proportion of patients with closed-loop spinal cord stimulation (49.3% vs 26.9%) were holistic responders at 24-month follow-up, with at least one minimal clinical important difference in all impaired domains (absolute risk difference: 22.4%, 95% CI 6.4% to 38.4%, p=0.012). The cumulative responder score was significantly greater for closed- loop patients at all time points and resulted in the achievement of more than three additional minimal clinical important differences at 24-month follow-up (mean difference 3.4, 95% CI 1.3 to 5.5, p=0.002). Neural activation was three times more accurate in closed-loop spinal cord stimulation (p<0.001 at all time points). Conclusion The results of this study suggest that closed- loop spinal cord stimulation can provide sustained clinically meaningful improvements in multiple domains and provide holistic improvement in the long-term for patients with chronic refractory pain. Trial registration number NCT02924129. [ABSTRACT FROM AUTHOR]

Background and Objectives: This study evaluated the long-term durability of the minimally invasive lumbar decompression (MILD) procedure in terms of functional improvement and pain reduction for patients with lumbar spinal stenosis and neurogenic claudication due to hypertrophic ligamentum flavum. This is a report of 2-year follow-up for MILD study patients.Methods: This prospective, multicenter, randomized controlled clinical study compared outcomes for 143 patients treated with MILD versus 131 treated with epidural steroid injections. Follow-up occurred at 6 months and at 1 year for the randomized phase and at 2 years for MILD subjects only. Oswestry Disability Index, Numeric Pain Rating Scale, and Zurich Claudication Questionnaire were used to evaluate function and pain. Safety was evaluated by assessing incidence of device-/procedure-related adverse events.Results: All outcome measures demonstrated clinically meaningful and statistically significant improvement from baseline through 6-month, 1-year, and 2-year follow-ups. At 2 years, Oswestry Disability Index improved by 22.7 points, Numeric Pain Rating Scale improved by 3.6 points, and Zurich Claudication Questionnaire symptom severity and physical function domains improved by 1.0 and 0.8 points, respectively. There were no serious device-/procedure-related adverse events, and 1.3% experienced a device-/procedure-related adverse event.Conclusions: MILD showed excellent long-term durability, and there was no evidence of spinal instability through 2-year follow-up. Reoperation and spinal fracture rates are lower, and safety is higher for MILD versus other lumbar spine interventions, including interspinous spacers, surgical decompression, and spinal fusion. Given the minimally invasive nature of this procedure, its robust success rate, and durability of outcomes, MILD is an excellent choice for first-line therapy for select patients with central spinal stenosis suffering from neurogenic claudication symptoms with hypertrophic ligamentum flavum.Clinical Trial Registration: This study was registered at ClinicalTrials.gov, identifier NCT02093520. [ABSTRACT FROM AUTHOR]

Background: Lumbar discogenic pain without pain mediated by a disc herniation, facet joints, or the sacroiliac joints, is common and often results in chronic, persistent pain and disability. After conservative treatment failure, injection therapy, such as an epidural injection, is frequently the next step considered in managing discogenic pain. The objective of this systematic review is to determine the efficacy of lumbar epidural injections in managing discogenic pain without radiculopathy, and compare this approach to lumbar fusion or disc arthroplasty surgery. Methods: A systematic review of randomized trials published from 1966 through October 2014 of all types of epidural injections and lumbar fusion or disc arthroplasty in managing lumbar discogenic pain was performed with methodological quality assessment and grading of evidence. The level of evidence was based on the grading of evidence criteria which, was conducted using 5 levels of evidence ranging from levels I to V. Results: Based on a qualitative assessment of the evidence for both approaches, there is Level II evidence for epidural injections, either caudal or lumbar interlaminar. Conclusions: The available evidence suggests fluoroscopically directed epidural injections provide long-term improvement in back and lower extremity pain for patients with lumbar discogenic pain. There is also limited evidence showing the potential effectiveness of surgical interventions compared to nonsurgical treatments., Version of Record

Objective: We investigated the effects of pain anxiety and a placebo/nocebo/neutral intervention on ice water-induced pain., Design: We divided 72 volunteers into high- and low-anxiety groups before randomly assigning them to experimental and control subgroups., Method: Participants completed preimmersion tests of pain anxiety, pain worry, and mood. We scored first immersion pain behavior, experience, and intensity. Each subgroup then received an instruction designed to elicit a positive (placebo), negative (nocebo), or neutral response. After repeating the pain worry test, we gathered second immersion pain scores, and participants repeated the mood test, completed the treatment credibility measure, and were debriefed., Outcome Measures: We used the Pain Anxiety Symptom Scale; self-rating Likert-type scales for pain worry, pain intensity, and pain-coping; the Multiple Affect Adjective Checklist (mood); timed measurements for pain threshold and pain tolerance; and a treatment credibility scale., Results: Pain anxiety and the placebo interventions significantly altered participants' pain scores, with best-to-worse scores reported by the low pain-anxiety/placebo, high anxiety/placebo, low anxiety/neutral, low anxiety/nocebo, high anxiety neutral, and high anxiety/nocebo groups. The high pain-anxiety group demonstrated the greatest response to the placebo/nocebo intervention in the expected directions in pain, worry, and anxious mood scores and in decreased self-confidence in managing pain (this was also negatively affected by the nocebo in each pain-anxiety group)., Conclusion: This study demonstrates that the interaction of the personality variable of pain anxiety with the placebo/nocebo response has an impact on pain, worry, and mood.

Objective: This additional analysis of data from a previously reported prospective trial comparing the effect of intraoperative alcohol or saline placebo neurolytic block in patients with pancreatic cancer was conducted in response to the development of a new theory, which explores the relationship of negative mood states to pain, pain-related behavior, and ultimately, longevity., Methods: The original study used a double-blind procedure to randomly assign 139 patients with histologically proven, unresectable pancreatic cancer to receive either an alcohol or a saline block. Data on visual analog pain, mood, and interference with activity were collected preoperatively and every 2 months postoperatively until death. The current analysis was conducted on the complete data sets received from 130 patients. Demographic data were submitted to chi-square analysis and to univariate and multivariate analysis of variance. Univariate and multivariate analyses of variance also compared 1) the effect of alcohol versus saline on pain, mood, interference of pain with activities, and longevity and 2) the impact of mood on pain with longevity as the dependent variable. Correlation and regression analyses examined the impact of mood on life expectancy., Results: The alcohol intervention had a significant positive effect on life duration and mood scores. High negative mood states correlated significantly with an increase in visual analog pain, the rating of pain intensity at its worse, and pain interference with patients' activities., Conclusion: In these subjects, the neurolytic block, as compared with medical management alone, improved pain, elevated mood, reduced pain interference with activity, and was associated with an increase in life expectancy.

Neuraxial infusion therapy is an excellent option for selected patients with severe pain. Both epidural and intrathecal systems can be effective for multiple pains and are titratable, nondestructive, and very safe. Intraspinal therapy requires low opioid doses, has no motor, sensory, or sympathetic effects, and may have a lower side-effect liability than systemic therapy. Although most oncologists do not refer patients for intrathecal therapy, a recent study indicated that more oncologists would if they knew more about the therapy and if patients requested it. When permanent systems are used, close follow-up is essential. To obtain the maximum benefit from intraspinal therapy, pain management physicians and oncologists must communicate with each other and work together as partners.

Unlabelled: Complex regional pain syndromes (CRPS) and neuropathic pain are often poorly controlled by conventional pharmacologic interventions. We administered 8-methyl-N-vanillyl-noneamide (capsaicin) at doses of 5%-10% to individuals with such disorders in this trial. Previous limitations to trials with larger-dose, topical concentrations of capsaicin included intense burning sensations experienced after application. To enable patients to tolerate the high concentrations, we first performed regional anesthesia. All patients reported at least some relief. Of 10 patients, 9 obtained substantial analgesia that lasted 1-18 wk. At Week 1 after therapy, the mean verbal analog scale (VAS) scores decreased from 8.0 to 3.0. At Week 4 after therapy, mean VAS score was 4.5. Analgesia lasted from < 1 wk (1 patient) to more than 50 wk (1 patient). Patients received one to eight treatments. With one exception, patients receiving more than one treatment obtained additional relief with subsequent treatment. Pain responsive to opioids was the only side effect of treatment. Large-dose capsaicin administered with regional anesthesia may effectively minimize refractory CRPS and neuropathic pain. A double-blind, placebo-controlled study in patients with bilateral peripheral neuropathy using epidural anesthesia with and without large-dose topical capsaicin is in progress., Implications: Sensory neuropathies are associated with many diseases. Pain from these disorders can produce greater disability than the primary disease processes themselves. Currently available therapies are limited. However, the intermittent application of large-dose topical capsaicin may provide significant pain relief, decrease chronic analgesic dependence, and decrease aggregate health care expenditures.

Background and Objectives: Local anesthetic agents with a duration of action longer than the currently available local anesthetics could have widespread clinical application for the treatment of both chronic and acute pain. Over the last several decades, several different approaches have been used in the development of ultra-long-acting agents. There are currently promising preparations in development which may prove clinically useful in the near future., Methods: A Medline search was conducted for relevant articles published in peer-reviewed journals between 1971 and 1996. Investigations related to prolongation of the effect of local anesthetics either by alterations in the local anesthetic molecule, use of new or novel agents, or use of new delivery systems were reviewed. In addition, bibliographies of relevant articles were searched to capture any articles that were missed by the Medline search., Results: Over the last several decades, numerous attempts have been made to prolong the duration of action of local anesthetics. Initially, research focused on alterations in the local anesthetic molecule or the identification of new agents with local anesthetic action. Recently, the focus of much of the work has shifted to new drug-delivery systems such as polymers and liposomes., Conclusions: Although encouraging results have been reported in the literature, there is currently no agent or delivery system that has shown reliable and practical prolongation of local anesthetic effect in humans. There have been several encouraging reports in animals that have shown local anesthetic effects lasting up to several days, but these results must be validated and then performed in human studies before a clinically useful agent is found. Further research is warranted.