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Aim: The Combining Mechanisms for Better Outcomes randomized controlled trial assessed the effectiveness of various spinal cord stimulation (SCS) modalities for chronic pain. Specifically, combination therapy (simultaneous use of customized sub-perception field and paresthesia-based SCS) versus monotherapy (paresthesia-based SCS) was evaluated. Methods: Participants were prospectively enrolled (key inclusion criterion: chronic pain for ≥6 months). Primary end point was the proportion with ≥50% pain reduction without increased opioids at the 3 month follow-up. Patients were followed for 2 years. Results: The primary end point was met (n = 89; p Clinical Trial Registration: NCT03689920 ( ClinicalTrials.gov ), Combining Mechanisms for Better Outcomes (COMBO)

BACKGROUND: T(1ρ) has been extensively reported as a sensitive biomarker of biochemical changes in the nucleus pulposus (NP) and annulus fibrosis of intervertebral discs (IVDs). However, no T(1ρ) study of cartilaginous endplates (CEPs) has yet been reported because the relatively long echo times (TEs) of conventional clinical T(1ρ) sequences cannot effectively capture the fast-decaying magnetic resonance signals of CEPs, which have very short T(2)/T(2)*s. This can be overcome by using ultrashort echo time (UTE) T(1ρ) acquisitions. METHODS: Seventeen subjects underwent UTE with adiabatic T(1ρ) preparation (UTE-Adiab-T(1ρ)) and T(2)-weighted fast spin echo imaging of their lumbar spines. Each IVD was manually segmented into seven regions (i.e., outer anterior annulus fibrosis, inner anterior annulus fibrosis, outer posterior annulus fibrosis, inner posterior annulus fibrosis, superior CEP, inferior CEP, and NP). T(1ρ) values of these sub-regions were correlated with IVD modified Pfirrmann grades and subjects’ ages. In addition, T(1ρ) values were compared in subjects with and without low back pain (LBP). RESULTS: Correlations of T(1ρ) values of the outer posterior annulus fibrosis, superior CEP, inferior CEP, and NP with modified Pfirrmann grades were significant (P

Objective The University of California (UC) leadership sought to develop a robust educational response to the epidemic of opioid-related deaths. Because the contributors to this current crisis are multifactorial, a comprehensive response requires educating future physicians about safe and effective management of pain, safer opioid prescribing, and identification and treatment of substance use disorder (SUD). Methods The six UC medical schools appointed an opioid crisis workgroup to develop educational strategies and a coordinated response to the opioid epidemic. The workgroup had diverse specialty and disciplinary representation. This workgroup focused on developing a foundational set of educational competencies for adoption across all UC medical schools that address pain, SUD, and public health concerns related to the opioid crisis. Results The UC pain and SUD competencies were either newly created or adapted from existing competencies that addressed pain, SUD, and opioid and other prescription drug misuse. The final competencies covered three domains: pain, SUD, and public health issues related to the opioid crisis. Conclusions The authors present a novel set of educational competencies as a response to the opioid crisis. These competencies emphasize the subject areas that are fundamental to the opioid crisis: pain management, the safe use of opioids, and understanding and treating SUD.

Contributors to the ongoing epidemic of prescription opioid abuse, addiction, and death include opioid tolerance, withdrawal symptoms, and possibly opioid-induced hyperalgesia (OIH). Thirty stable chronic nonmalignant pain patients entered a 6-month long, randomized, double-blind, dose-response, 2-center trial of the potent opioid levorphanol, conducted over a decade ago during an era of permissive opioid prescribing. Eleven were taking no opioids at study entry and eleven were taking between 35 and 122 morphine equivalents. Five weeks titration preceded twenty weeks stable dosing. Tolerance and OIH were inferred individually based on chronic pain ratings, brief pain inventory scores, and results of the brief thermal sensitization model at 5 opioid dosing sessions. Seventeen patients completed. The average final daily opioid dose was 132; range 14 to 300; average addition 105 morphine equivalents. After observed dosing, the brief thermal sensitization area of hyperalgesia changed minimally but the painfulness of skin heating was reduced. Weekly 0 to 100 visual analog scale pain ratings (average 64 at study entry, 48 at end titration, 45 at end stable dosing) decreased a median 19%, but 8 completed with higher visual analog scale ratings. Three completers had evidence of both tolerance and hyperalgesia. A fully-powered trial similar to this feasibility study is ethically questionable. A large-scale pragmatic trial is more realistic. TRIAL REGISTRATION: NCT00275249 Evolution of Analgesic Tolerance With Opioids PERSPECTIVE: A double-blind, 6-month, high-dose opioid feasibility trial, completed years ago, provides critically important data for clinically defining analgesic tolerance and OIH. Overall benefit was small, and 18% of patients had evidence of both tolerance and OIH. Future work requires a different approach than a classic randomized controlled trial design.

BackgroundThe past two decades have witnessed a surge in the use of lumbar facet blocks and radiofrequency ablation (RFA) to treat low back pain (LBP), yet nearly all aspects of the procedures remain controversial.MethodsAfter approval by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine, letters were sent to a dozen pain societies, as well as representatives from the US Departments of Veterans Affairs and Defense. A steering committee was convened to select preliminary questions, which were revised by the full committee. Questions were assigned to 4–5 person modules, who worked with the Subcommittee Lead and Committee Chair on preliminary versions, which were sent to the full committee. We used a modified Delphi method, whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chair, who incorporated the comments and sent out revised versions until consensus was reached.Results17 questions were selected for guideline development, with 100% consensus achieved by committee members on all topics. All societies except for one approved every recommendation, with one society dissenting on two questions (number of blocks and cut-off for a positive block before RFA), but approving the document. Specific questions that were addressed included the value of history and physical examination in selecting patients for blocks, the value of imaging in patient selection, whether conservative treatment should be used before injections, whether imaging is necessary for block performance, the diagnostic and prognostic value of medial branch blocks (MBB) and intra-articular (IA) injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for a prognostic block, how many blocks should be performed before RFA, how electrodes should be oriented, the evidence for larger lesions, whether stimulation should be used before RFA, ways to mitigate complications, if different standards should be applied to clinical practice and clinical trials and the evidence for repeating RFA (see table 12 for summary).ConclusionsLumbar medial branch RFA may provide benefit to well-selected individuals, with MBB being more predictive than IA injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of more false-negatives. Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Background The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial. Methods In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4–5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement. Results Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation. Conclusions Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

ObjectiveTo apply the sequential up–down method to a human experimental pain model in order to examine the opioid-sparing effect of oral pregabalin on intravenous alfentanil.DesignDouble-blind, randomized, crossover.SettingAcademic university medical center.SubjectsThirty-one healthy males.MethodsThe median effective plasma concentration of intravenous alfentanil was determined under two conditions: alfentanil alone (phase I) and alfentanil+ pregabalin (300 mg orally) (phase II). The alfentanil plasma level (after a computer-controlled infusion) producing a success criterion (at least 30% intradermal capsaicin-induced pain reduction compared with placebo) was used to determine higher or lower doses for each sequential subject. The median dose producing a success criterion and its confidence interval were determined.ResultsOn the basis of the t test for a difference across phase and regression coefficients across groups, there was no opioid-sparing effect of pregabalin on alfentanil. Four subjects in phase I and five subjects in phase II did not complete the study. Two in phase I were technical failures, with the rest in both phases stopped because of side effects. Of the subjects who completed the study, six of 19 subjects in phase I and 11 of 12 subjects in phase II reported side effects.ConclusionsWhen the intradermal capsaicin-induced pain model was used in healthy volunteers, oral pregabalin had no opioid-sparing effects on intravenous alfentanil. This experimental model may be useful in studying analgesic interactions.

Cannabinoids, cannabis, and cannabis-based medicines (CBMs) are increasingly used to manage pain, with limited understanding of their efficacy and safety. We summarised efficacy and adverse events (AEs) of these types of drugs for treating pain using randomised controlled trials: in people of any age, with any type of pain, and for any treatment duration. Primary outcomes were 30% and 50% reduction in pain intensity, and AEs. We assessed risk of bias of included studies, and the overall quality of evidence using GRADE. Studies of 7 days treatment duration were analysed separately. We included 36 studies (7217 participants) delivering cannabinoids (8 studies), cannabis (6 studies), and CBM (22 studies); all had high and/or uncertain risk of bias. Evidence of benefit was found for cannabis 7 days (risk difference 0.06, 95% confidence interval 0.01-0.12; 6 trials, 1484 patients, very low-quality evidence). No other beneficial effects were found for other types of cannabinoids, cannabis, or CBM in our primary analyses; 81% of subgroup analyses were negative. Cannabis, nabiximols, and delta-9-tetrahydrocannabinol had more AEs than control. Studies in this field have unclear or high risk of bias, and outcomes had GRADE rating of low- or very low-quality evidence. We have little confidence in the estimates of effect. The evidence neither supports nor refutes claims of efficacy and safety for cannabinoids, cannabis, or CBM in the management of pain.

The President of the International Association for the Study of Pain (IASP) established a Taskforce on Cannabis and Cannabinoid Analgesia, to systematically examine the evidence on (i) analgesic pharmacology of cannabinoids and preclinical evidence on their efficacy in animal models of injury-related or pathological persistent pain, (ii) the clinical efficacy of cannabis, cannabinoids and cannabis-based medicines (CBM) for pain, (iii) harms related to long-term use of cannabinoids, as well as (iv) societal issues and policy implications related to the use of these compounds for pain management. Here, we summarize key knowledge gaps identified in the Taskforce outputs and propose a research agenda for generating high-quality evidence on the topic. The systematic assessment of preclinical and clinical literature identified gaps in rigor of study design and reporting across the translational spectrum. We provide recommendations to improve the quality, rigor, transparency, and reproducibility of preclinical and clinical research on cannabis and cannabinoids for pain, as well as for the conduct of systematic reviews on the topic. Gaps related to comprehensive understanding of the endocannabinoid system and cannabinoid pharmacology, including pharmacokinetics and drug formulation aspects, are discussed. We outline key areas where high quality clinical trials with cannabinoids are needed. Important remaining questions about long-term and short-term safety of cannabis and cannabinoids are emphasized. Finally, regulatory, societal and policy challenges associated with medicinal and non-medicinal use of cannabis are highlighted, with recommendations for improving patient safety and reducing societal harms in the context of pain management.

Ultrashort echo time (UTE) sequences can image tissues with transverse T(2)/T(2)* relaxations too short to be efficiently observed on routine clinical MRI sequences, such as the vertebral body cartilaginous endplate (CEP). Here, we describe a 3D adiabatic inversion recovery-prepared fat-saturated ultrashort echo time (3D IR-FS-UTE) sequence to highlight the CEP of vertebral bodies in comparison to the intervertebral disc (IVD) and bone marrow fat (BF) at 3T. The IR-FS-UTE sequence used a 3D UTE sequence combined with an adiabatic IR preparation pulse centered in the middle of the water and fat peaks, while a fat saturation module was used to suppress the signal from fat. A slab-selective half pulse was used for signal excitation, and a 3D center-out cones trajectory was used for more efficient data sampling. The 3D IR-FS-UTE sequence was applied to an ex vivo human spine sample, as well as the spines of six healthy volunteers and of three patients with back pain. Bright continue lines representing signal from CEP were found in healthy IVDs. The measured contrast-to-noise ratio (CNR) was 18.5±4.9 between the CEP and BF, and 20.3±4.15 between the CEP and IVD for the six volunteers. Abnormal IVDs showed CEP discontinuity or irregularity in the sample and patients’ studies. In conclusion, the proposed 3D IR-FS-UTE sequence is feasible for imaging of the vertebral body’s CEP in vivo with high contrast.

Opioids have been reported to increase the risk for sleep-disordered breathing (SDB) in patients with noncancer chronic pain on opioid therapy. This study aims to determine the pooled prevalence of SDB in opioid users with chronic pain and compare it with patients with pain:no opioids and no pain:no opioids.A literature search of PubMed, Medline, Embase, and Cochrane Central Register of Controlled Trials was conducted. We included all observational studies that reported the prevalence of SDB in patients with chronic pain on long-term opioid therapy (≥3 months). The primary outcome was the pooled prevalence of SDB in opioid users with chronic pain (pain:opioids group) and a comparison with pain:no opioids and no pain:no opioids groups. The meta-analysis was performed using a random-effects model.After screening 1,404 studies, 9 studies with 3,791 patients were included in the meta-analysis (pain:opioids group, n = 3181 [84%]; pain:no opioids group, n = 359 [9.4%]; no pain:no opioids group, n = 251 [6.6%]). The pooled prevalence of SDB in the pain:opioids, pain:no opioids, and no pain:no opioids groups were 91%, 83%, and 72% in sleep clinics and 63%, 10%, and 75% in pain clinics, respectively. Furthermore, in the pain: opioids group, central sleep apnea prevalence in sleep and pain clinics was 33% and 20%, respectively.The pooled prevalence of SDB in patients with chronic pain on opioid therapy is not significantly different compared with pain:no opioids and no pain:no opioids groups and varies considerably depending on the site of patient recruitment (ie, sleep vs pain clinics). The prevalence of central sleep apnea is high in sleep and pain clinics in the pain:opioids group. Clinical Trial Registration: Registry: PROSPERO: International prospective register of systematic reviews; Name: Prevalence of sleep disordered breathing, hypoxemia and hypercapnia in patients on oral opioid therapy for chronic pain management; URL: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42018103298; Identifier: CRD42018103298.

Background: A recent meta-analysis affirmed the benefit of medicinal cannabis for chronic neuropathic pain, a disabling and difficult-to-treat condition. As medicinal cannabis use is becoming increasingly prevalent among Americans, an exploration of its economic feasibility is warranted. We present this cost-effectiveness analysis of adjunctive cannabis pharmacotherapy for chronic peripheral neuropathy. Materials and Methods: A published Markov model comparing conventional therapies for painful diabetic neuropathy was modified to include arms for augmenting first-line, second-line (if first-line failed), or third-line (if first- and second-line failed) therapies with smoked cannabis. Microsimulation of 1,000,000 patients compared the cost (2017 U.S. dollars) and effectiveness (quality-adjusted life years [QALYs]) of usual care with and without adjunctive cannabis using a composite of third-party and out-of-pocket costs. Model efficacy inputs for cannabis were adapted from clinical trial data. Adverse event rates were derived from a prospective study of cannabis for chronic noncancer pain and applied to probability inputs for conventional therapies. Cannabis cost was derived from retail market pricing. Parameter uncertainty was addressed with one-way and probabilistic sensitivity analysis. Results: Adding cannabis to first-line therapy was incrementally less effective and costlier than adding cannabis to second-line and third-line therapies. Third-line adjunctive cannabis was subject to extended dominance, that is, the second-line strategy was more effective with a more favorable incremental cost-effectiveness ratio of $48,594 per QALY gained, and therefore, third-line adjunctive cannabis was not as cost-effective. At a modest willingness-to-pay threshold of $100,000/QALY gained, second-line adjunctive cannabis was the strategy most likely to be cost-effective. Conclusion: As recently proposed willingness-to-pay thresholds for the United States health marketplace range from $110,000 to $300,000 per QALY, cannabis appears cost-effective when augmenting second-line treatment for painful neuropathy. Further research is warranted to explore the long-term benefit of smoked cannabis and standardization of its dosing for chronic neuropathic pain.

Purpose: To analyse how effective was the USA, compared to Other Western Countries (OWC) in reducing premature deaths 1989-2015. Design: This population-based study is a cost-effective model of fiscal input into health related to clinical outputs, recognising socio-economic factors influence health outcomes. Using World Bank data for total % GDP-Expenditure-on-Health, and, WHO data for Child (0-4), Adult (55-74) and Age-Standardised-Death-Rates rates per million America is compared with OWC. Cost-Effective Ratios (CEF) are calculated and Confidence Intervals (95%) tests USA against each OWC. `Excess’ deaths are calculated between the most and least expensive health systems. Setting: Twenty Other Western countries. Patients: National populations.

BACKGROUND: While conventional MRI sequences cannot visualize tissues from the osteochondral junction (OCJ) due to these tissues’ short transverse T(2)/T(2)* relaxations, ultrashort echo time (UTE) sequences can overcome this limitation. A 2D UTE sequence with a dual adiabatic inversion recovery preparation (DIR-UTE) for selective imaging of short T(2) tissues with high contrast has previously been developed, but high sensitivity to eddy currents and aliased out-of-slice excitation make it difficult to image the thin layer of the OCJ in vivo. Here, we combine the DIR scheme with a 3D UTE Cones sequence for volumetric imaging of OCJ tissues in vivo, aiming to generate higher OCJ contrast compared with a recently developed single IR-prepared UTE sequence with a fat saturation module (IR-FS-UTE). METHODS: All sequences were implemented on a 3T clinical scanner. The DIR-UTE Cones sequence combined a 3D UTE Cones sequence with two narrow-band adiabatic IR preparation pulses centered on water and fat spectrum frequencies, respectively. The 3D DIR-UTE Cones sequence was first applied to a phantom, then to the knees of four healthy volunteers and four patients diagnosed with osteoarthritis and compared to the IR-FS-UTE sequence. RESULTS: In both phantom and volunteer studies, the proposed DIR-UTE Cones sequence showed much higher contrast for OCJ imaging than the IR-FS-UTE sequence did. The 3D DIR-UTE Cones sequence showed a significantly higher contrast-to-noise ratio (CNR) between the OCJ and subchondral bone fat (BF) (mean, standard deviation (SD): 25.7 ± 2.3) and between the OCJ and superficial layers of cartilage (SC) (mean, SD: 22.2 ± 3.5) compared to the IR-FS-UTE sequence (mean, SD: 10.8 ± 2.5 and 16.3 ± 2.6, respectively). CONCLUSIONS: The 3D DIR-UTE Cones sequence is feasible for imaging of the OCJ region of the knee in vivo and produces both high resolution and high contrast.

Jan M Schilling,1 Chloe G Hughes,1 Mark S Wallace,2 Michelle Sexton,2 Miroslav Backonja,1,3 Tobias Moeller-Bertram1 1Clinical Research, Vitamed Research, Palm Desert, CA, USA; 2Department of Anesthesiology, University of California San Diego, San Diego, CA, USA; 3Department of Neurology, University of Washington, Seattle, WA, USACorrespondence: Jan M Schilling; Tobias Moeller-BertramClinical Research, Vitamed Research, LLC, 44630 Monterey Ave, Suite 100, Palm Desert, CA, 92260, USAEmail jan@vitamedresearch.com; toby@vitamedresearch.comIntroduction: Cannabis products have become easily available and accessible after decriminalization of cannabis for recreational and medicinal use in many states. Cannabidiol (CBD) has been of increasing interest to patients and is being used to self-medicate a variety of ailments. However, very limited information is available to patients and providers to form an educated opinion regarding its indicated use to treat the many conditions this substance has been implied to be helpful for. The aim of this survey was to learn about participants’ attitudes and views towards cannabis-based medicine (CBM) with a focus on perception of “CBD” and its potential role for pain management.Materials and Methods: We recruited survey participants from seven pain management clinics in Southern California to learn about their knowledge, beliefs, and personal experience with CBD products. After Institutional Review Board (IRB) review, an internet survey platform was utilized to administer the survey online.Results: A total of 253 participants answered the survey. Participants were 45.4 ± 13.8 (Mean ± SD) years of age, the majority identified as white (56.1%), had an annual household income of less than $20,000, and were primarily insured by Medicare (22.5%) or Medicaid (43.9%). Among participants, 62.0% reported trying a CBD product [including products containing delta-9-tetrahydrocannabinol (THC)]. The majority responded that these products have helped their pain (59.0%) and allowed them to reduce their pain medications (67.6%), including opioids (53.7%). They reported believing that CBD was a good treatment option (71.1%), not harmful (74.9%), and not addictive (65.3%). About half of participants (51.9%) report that they would be more comfortable with their physician prescribing CBD products. The overall attitude and experience of participants regarding CBD is reported as positive, while 91.9% of people expressed a desire to learn more about it.Summary: In summary, most participants expressed a positive attitude about CBD products as a treatment option, reported positive outcomes when used for multiple different conditions, and would prefer to obtain information about and prescription for CBD from their physicians.Keywords: survey, cannabidiol, CBD, medical marijuana, cannabis

The growing demand for improved pain treatments together with expanding legalization of, and access to, cannabinoids, cannabis, and cannabis-based medicines has intensified the focus on risk-benefit considerations in pain management. Given limited harms data from analgesic clinical trials, we conducted an overview of systematic reviews focused on all harms possibly relevant to patients receiving cannabinoids for pain management. This PROSPERO-registered, PRISMA-compliant systematic overview identified 79 reviews, encompassing over 2200 individual reports about psychiatric and psychosocial harms, cognitive/behavioral effects, motor vehicle accidents, cardiovascular, respiratory, cancer-related, maternal/fetal, and general harms. Reviews, and their included studies, were of variable quality. Available evidence suggests variable associations between cannabis exposure (ranging from monthly to daily use based largely on self-report) and psychosis, motor vehicle accidents, respiratory problems, and other harms. Most evidence comes from settings other than that of pain management (eg, nonmedicinal and experimental) but does signal a need for caution and more robust harms evaluation in future studies. Given partial overlap between patients receiving cannabinoids for pain management and individuals using cannabinoids for other reasons, lessons from the crisis of oversupply and overuse of opioids in some parts of the world emphasize the need to broadly consider harms evidence from real-world settings. The advancement of research on cannabinoid harms will serve to guide optimal approaches to the use of cannabinoids for pain management. In the meantime, this evidence should be carefully examined when making risk-benefit considerations about the use of cannabinoids, cannabis, and cannabis-based medicine for chronic pain.

Background and ObjectivesThe Patient Registry of Intrathecal Ziconotide Management evaluated the long-term effectiveness and safety of intrathecal ziconotide.MethodsThe study was a prospective, multicenter observational study of intrathecal ziconotide in US clinical practice. Patients were adults with severe chronic pain that warranted intrathecal therapy. Ziconotide was initiated as the single agent in the pump; however, other intrathecal medications were permitted. The primary efficacy outcome was ≥30% reduction in numeric pain rating scale score from baseline at week 12. A secondary outcome was patient global impression of change. Adverse events were solicited at each visit.ResultsThe registry enrolled 93 patients. Seventy-four and 28 patients completed 12 weeks and 18 months of treatment, respectively. In the overall patient population, 17.4% had ≥30% pain reduction from baseline at week 12, with a mean reduction in pain of 10.9%. At month 18, 38.5% of patients had ≥30% pain reduction from baseline, with a mean pain reduction of 24.7%. Patient-rated improvement was reported in 67% of patients at week 12 and 71% at month 18. Almost all patients experienced adverse events, the most common of which were nausea (25.8%), confusional state (22.6%), and dizziness (20.4%).ConclusionsFinal study analyses showed that intrathecal ziconotide provided clinically meaningful pain relief in 17.4% and 38.5% of patients at week 12 and month 18, respectively. At these same time points, patient-rated improvement was reported in at least two-thirds of patients. The safety profile was consistent with that listed in the ziconotide prescribing information.

In health and disease, the somatosensory system has been interrogated with standardized research techniques, collectively referred to as quantitative sensory testing (QST). In neuropathic pain, QST has been used to characterize multiple sensory derangements. However, the use of QST outside the lab has been limited by several factors, including a lack of standardization, variability in procedural technique, and duration of testing that would be unacceptable for clinic. To address these shortcomings, the Neuropathic Pain Research Consortium (NPRC) designed an easy and low-cost “bedside” QST procedure. To test the hypothesis that this procedure would be clinically reliable over time and across different examiners, a multi-site, blinded study was performed in subjects with postherpetic neuralgia. Generally, agreement between two examiners and over two study visits with one examiner was high. Additionally, intraclass correlation coefficients and Kappa statistics calculated showed that the battery of QST tests included were highly reliable. Interestingly, mechanical modalities (light brush, pinprick, pressure, and vibration) showed the highest reliability. The least reliable modalities were cool (room temperature) and warmth (38°C). These data demonstrate that the NPRC beside QST protocol is reliable across examiner and over time, providing a validated QST tool for use in clinical practice and clinical trials. PERSPECTIVE: This blinded, multi-center trial in 32 patients with postherpetic neuralgia demonstrates bedside quantitative sensory testing is reliable and suitable as a clinical trial outcome. The novel bedside battery could be used in clinical trials or in clinical practice over time given the reliability data presented in this article.

Background and aimsWhile the United States has been experiencing an opioid epidemic, 29 states and Washington DC have legalized cannabis for medical use. This study examined whether state-wide medical cannabis legalization was associated with reduction in opioids received by Medicaid enrollees.DesignSecondary data analysis of state-level opioid prescription records from 1993-2014 Medicaid State Drug Utilization Data. Linear time-series regressions assessed the associations between medical cannabis legalization and opioid prescriptions, controlling for state-level time-varying policy covariates (such as prescription drug monitoring programs) and socio-economic covariates (such as income).SettingUnited States.ParticipantsDrug prescription records for patients enrolled in fee-for-service Medicaid programs that primarily provide health-care coverage to low-income and disabled people.MeasurementsThe primary outcomes were population-adjusted number, dosage and Medicaid spending on opioid prescriptions. Outcomes for Schedule II opioids (e.g. hydrocodone, oxycodone) and Schedule III opioids (e.g. codeine) were analyzed separately. The primary policy variable of interest was the implementation of state-wide medical cannabis legalization.FindingsFor Schedule III opioid prescriptions, medical cannabis legalization was associated with a 29.6% (P=0.03) reduction in number of prescriptions, 29.9% (P=0.02) reduction in dosage and 28.8% (P=0.04) reduction in related Medicaid spending. No evidence was found to support the associations between medical cannabis legalization and Schedule II opioid prescriptions. Permitting medical cannabis dispensaries was not associated with Schedule II or Schedule III opioid prescriptions after controlling for medical cannabis legalization. It was estimated that, if all the states had legalized medical cannabis by 2014, Medicaid annual spending on opioid prescriptions would be reduced by 17.8 million dollars.ConclusionState-wide medical cannabis legalization appears to have been associated with reductions in both prescriptions and dosages of Schedule III (but not Schedule II) opioids received by Medicaid enrollees in the United States.

Toll-like receptors (TLRs) are a family of pattern-recognition receptors that initiate signaling in innate and adaptive immune pathways. The highly conserved family of transmembrane proteins are comprised of an extracellular domain that recognizes exogenous and endogenous danger molecules and an ectodomain that activates downstream pathways in response. Recent studies suggest that continuous activation or dysregulation of TLR signaling may contribute to chronic disease states. The receptor is located not only on inflammatory cells (meningeal and peripheral macrophages) but on neuraxial glia (microglia and astrocytes), schwann cells, fibroblasts, dorsal root ganglia and dorsal horn neurons. Procedures blocking TLR functionality have shown pronounced effects on pain behavior otherwise observed in models of chronic inflammation and nerve injury. This review addresses the role of TLR4 as an emerging therapeutic target for the evolution of persistent pain and its role in non canonical signaling mediating anomalous proalgesic actions of opiates. Accordingly, molecules targeting inhibition of this receptor have promise as disease modifying and opioid sparing alternatives for persistent pain states.

Objective The objective of this study was to evaluate the efficacy of a telephone-delivered, home-based cognitive-behavioral intervention for chronic low back pain in comparison to a matched supportive care (SC) treatment. Methods Participants (N=66) were patients with chronic back pain that were randomized to either an 8-week Cognitive-Behavioral Therapy (CBT) or a SC condition matched for contact frequency, format, and time. Participants completed validated measures of improvement in back pain disability, pain severity, and overall improvement. Results Intent-to-treat analyses at posttreatment showed that the treatment groups not show significantly different improvements in back pain disability (mean changes, -2.4 and -2.6 for CBT and SC, respectively; Cohen d, 0.49 and 0.55, respectively) or reductions in pain severity (mean changes, -0.9 and -1.4 for CBT and SC respectively; Cohen d, 0.50, and 0.90, respectively). Participants rated their overall improvement levels at 31% (CBT) versus 18.5% (SC). Discussion Results from this clinical trial suggest that home-based, telephone-delivered CBT and SC treatments did not significantly differ in their benefits for back pain severity and disability, and may warrant further research for applications to hospital settings. Major limitations included recruitment difficulties that underpowered primary analyses, the lack of objective improvement measures, and the absence of a usual care/untreated control group for comparisons.

The Patient Assessment for Low Back Pain–Symptoms is a newly developed patient-reported outcome instrument to assess specific symptoms of chronic low back pain for use in clinical trials and practice., We describe the mixed-methods (qualitative and quantitative) development and preliminary validation of the Patient Assessment for Low Back Pain–Symptoms (PAL-S), a patient-reported outcome measure for use in chronic low back pain (cLBP) clinical trials. Qualitative methods (concept elicitation and cognitive interviews) were used to identify and refine symptom concepts and quantitative methods (classical test theory and Rasch measurement theory) were used to evaluate item- and scale-level performance of the measure using an iterative approach. Patients with cLBP participated in concept elicitation interviews (N = 43), cognitive interviews (N = 38), and interview-based assessment of paper-to-electronic mode equivalence (N = 8). A web-based sample of patients with self-reported cLBP participated in quantitative studies to evaluate preliminary (N = 598) and revised (n = 401) drafts and a physician-diagnosed cohort of patients with cLBP (N = 45) participated in preliminary validation of the measure. The PAL-S contained 14 items describing symptoms (overall pain, sharp, prickling, sensitive, tender, radiating, shocking, shooting, burning, squeezing, muscle spasms, throbbing, aching, and stiffness). Item-level performance, scale structure, and scoring seemed to be appropriate. One-week test–retest reproducibility was acceptable (intraclass correlation coefficient 0.81 [95% confidence interval, 0.61-0.91]). Convergent validity was demonstrated with total score and MOS-36 Bodily Pain (Pearson correlation −0.79), Neuropathic Pain Symptom Inventory (0.73), Roland-Morris Disability Questionnaire (0.67), and MOS-36 Physical Functioning (−0.65). Individual item scores and total score discriminated between numeric rating scale tertile groups and painDETECT categories. Respondent interpretation of paper and electronic administration modes was equivalent. The PAL-S has demonstrated content validity and is potentially useful to assess treatment benefit in cLBP clinical trials.

Experimental interventions that activate specific components of clinical pain are necessary for characterization of underlying mechanisms and pharmacology. Cutaneous hyperalgesia has been described that uses nonpainful heat to induce secondary hyperalgesia. This study evaluated the effect of intravenous alfentanil on experimental cutaneous hyperalgesia created using this method. Eighteen subjects participated in a randomized, double-blinded, placebo-controlled crossover study consisting of 2 sessions, 1 with alfentanil and 1 with placebo. Using a computer-controlled infusion pump, alfentanil or matching placebo was maintained at a constant plasma level of 75 ng/mL for 1 hour followed by the application of a 40°C heat stimulus to the right thenar eminence for 15 minutes. The temperature was raised by 1°C every 15 minutes until the subject reported pain or 45°C was reached. After the end point was reached, the temperature was maintained, and repeat testing was performed. The nonpainful heat created an area of secondary cutaneous hyperalgesia and significant decrease in mechanical pain threshold on heat-treated right vs untreated left during placebo administration. Alfentanil prevented the hypersensitivity when compared to placebo (P < .05) but failed to reduce the area of secondary hyperalgesia created by nonpainful heat when compared to placebo (P = .06). Neither alfentanil nor the heat lamp treatment showed any significant effect on other neurosensory measures. This study demonstrated a reliable production of cutaneous hyperalgesia using a nonpainful stimulus that is affected by the systemic delivery of alfentanil. This model for human cutaneous experimental pain may be a useful method for scientific characterization of analgesics.

Objective To identify patient-reported outcome (PRO) instruments that assess chronic low back pain (cLBP) symptoms (specifically pain qualities) and/or impacts for potential use in cLBP clinical trials to demonstrate treatment benefit and support labeling claims. Design Literature review of existing PRO measures. Methods Publications detailing existing PRO measures for cLBP were identified, reviewed, and summarized. As recommended by the US Food & Drug Administration (FDA) PRO development guidance, standard measurement characteristics were reviewed, including development history, psychometric properties (validity and reliability), ability to detect change, and interpretation of observed changes. Results Thirteen instruments were selected and reviewed: Low Back Pain Bothersomeness Scale, Neuropathic Pain Symptom Inventory, PainDETECT, Pain Quality Assessment Scale Revised, Revised Short Form McGill Pain Questionnaire, Low Back Pain Impact Questionnaire, Oswestry Disability Index, Pain Disability Index, Roland-Morris Disability Questionnaire, Brief Pain Inventory and Brief Pain Inventory Short Form, Musculoskeletal Outcomes Data Evaluation and Management System Spine Module, Orebro Musculoskeletal Pain Questionnaire, and the West Haven-Yale Multidimensional Pain Inventory Interference Scale. The instruments varied in the aspects of pain and/or impacts that they assessed, and none of the instruments fulfilled all criteria for use in clinical trials to support labeling claims based on recommendations outlined in the FDA PRO guidance. Conclusions There is an unmet need for a validated PRO instrument to evaluate cLBP-related symptoms and impacts for use in clinical trials.

This report examines the association between tetrahydrocannabinol (THC) plasma levels and pain response in a secondary analysis of data from a recent diabetic neuropathy study that demonstrated a dose-dependent reduction in spontaneous and elicited pain at specific time points. A randomized, double-blinded, placebo-controlled crossover study was conducted in sixteen patients with painful diabetic peripheral neuropathy. Subjects participated in four sessions, separated by 2 weeks, during each of which they were exposed to one of four conditions: placebo, or 1%, 4%, or 7% THC dose of cannabis. Baseline assessments of spontaneous and evoked pain were performed. Subjects were then administered aerosolized cannabis or placebo and pain intensity and cognitive testing at specific time points for 4 hours. A blood sample was drawn from the left antecubital vein for plasma assay of total THC at 0, 15, 30, 45, 60, 150, and 240 minutes. Associations were made between pain intensity, cognitive impairment and THC plasma levels in this secondary analysis. Results suggested a U-shaped relation whereby pain ratings are greatest at extreme (low and high) levels of THC. The therapeutic window appeared to fall between 16 ng/mL and 31 ng/mL THC plasma level. There was a significant linear effect of THC on only one out of the three cognitive tests. These findings stress the importance of measuring cannabinoid plasma levels when performing future research. Perspective: This analysis correlating plasma THC levels and pain reduction in diabetic neuropathy suggest a therapeutic window. Low and high THC levels had a negative association (no reduction) and THC levels within the window had a positive association (reduction). There was a minor negative linear effect of THC on cognitive function.

BackgroundAlthough opioids play a critical role in the management of cancer pain, the ongoing opioid epidemic has raised concerns regarding their persistent use and abuse. We lack data-driven tools in oncology to understand the risk of adverse opioid-related outcomes. This project seeks to identify clinical risk factors and create a risk score to help identify patients at risk of persistent opioid use and abuse.MethodsWithin a cohort of 106 732 military veteran cancer survivors diagnosed between 2000 and 2015, we determined rates of persistent posttreatment opioid use, diagnoses of opioid abuse or dependence, and admissions for opioid toxicity. A multivariable logistic regression model was used to identify patient, cancer, and treatment risk factors associated with adverse opioid-related outcomes. Predictive risk models were developed and validated using a least absolute shrinkage and selection operator regression technique.ResultsThe rate of persistent opioid use in cancer survivors was 8.3% (95% CI = 8.1% to 8.4%); the rate of opioid abuse or dependence was 2.9% (95% CI = 2.8% to 3.0%); and the rate of opioid-related admissions was 2.1% (95% CI = 2.0% to 2.2%). On multivariable analysis, several patient, demographic, and cancer and treatment factors were associated with risk of persistent opioid use. Predictive models showed a high level of discrimination when identifying individuals at risk of adverse opioid-related outcomes including persistent opioid use (area under the curve [AUC] = 0.85), future diagnoses of opioid abuse or dependence (AUC = 0.87), and admission for opioid abuse or toxicity (AUC = 0.78).ConclusionThis study demonstrates the potential to predict adverse opioid-related outcomes among cancer survivors. With further validation, personalized risk-stratification approaches could guide management when prescribing opioids in cancer patients.

Supplemental Digital Content is Available in the Text., Introduction: With the increasing availability of cannabis and cannabinoids and their potential utility for pain treatment, there is a growing need to evaluate the risk-benefit considerations of cannabinoids for the management of pain. As part of the IASP Cannabis and Cannabinoids Task Force, this protocol describes a planned overview of systematic reviews summarizing the risks of harm with cannabinoids that are relevant to patients receiving pain treatment. Methods: This overview will involve literature searches of several databases and a defined search strategy that will target systematic reviews or meta-analyses of cannabinoids where harms are the primary focus. Data extraction will include various features of the cannabinoid(s) and the harm(s) being studied as well as other methodological features of each included systematic review. Methodological quality of each included review will be assessed using AMSTAR-2 as well as compliance with the PRISMA harms checklist. Prospero registration pending. Discussion: The broad overview of reviews defined by this protocol is expected to synthesize available good quality evidence of harms that will help inform risk-benefit considerations about the use of cannabinoids for pain management.

Objectives Medical marijuana use may substitute prescription opioid use, whereas nonmedical marijuana use may be a risk factor of prescription opioid misuse. This study examined the associations between recreational marijuana legalization and prescription opioids received by Medicaid enrollees. Methods State-level quarterly prescription drug utilization records for Medicaid enrollees during 2010–2017 were obtained from Medicaid State Drug Utilization Data. The primary outcome, opioid prescriptions received, was measured in three population-adjusted variables: number of opioid prescriptions, total doses of opioid prescriptions in morphine milligram equivalents, and related Medicaid spending, per quarter per 100 enrollees. Two difference-in-difference models were used to test the associations: eight states and DC that legalized recreational marijuana during the study period were first compared among themselves, then compared to six states with medical marijuana legalized before the study period. Schedule II and III opioids were analyzed separately. Results In models comparing eight states and DC, legalization was not associated with Schedule II opioid outcomes; having recreational marijuana legalization effective in 2015 was associated with reductions in number of prescriptions, total doses, and spending of Schedule III opioids by 32% (95% CI: (−49%, −15%), p = 0.003), 30% ((−55%, −4.4%), p = 0.027), and 31% ((−59%, −3.6%), p = 0.031), respectively. In models comparing eight states and DC to six states with medical marijuana legalization, recreational marijuana legalization was not associated with any opioid outcome. Conclusions No evidence suggested that recreational marijuana legalization increased prescription opioids received by Medicaid enrollees. There was some evidence in some states for reduced Schedule III opioids following the legalization.

Purpose: To compare the UK Child (0-4) and Adult (55-74) Mortality with twenty developed countries 1989-2014 to explore whether the UK has lower priorities for children? Design: WHO data on Child and Adult mortality examined within context of World Bank %GDPExpenditure-on-Health (%GDPEH) data and Income Inequality i.e Relative poverty. Settings: 21 developed countries. Patients: National populations. Outcome Measures: Child and Adult mortality rates per million (pm) population between 1989-2014. Confi dence Intervals compares UK with other developed countries (ODC); odds ratios of average European to UK mortality calculated. Correlations explore links between mortalities, %GDPEH and Income Inequality. Important Results: Highest average 1980-2014 %GDPEH is USA 12.6%, the lowest UK 7.0%. European average 8.5% a UK to European odds ratio 1:1.21. Widest Income Inequality was USA 15.9 times, UK 13.8 was third, European average 8.5times. Child Mortality fell in every country but eleven signifi cantly better than Britain. Highest was USA 1383pm the UK fourth at 967pm. European average 728pm yielded a European to UK odds ratio of 1:1.33. Income Inequality and CRM signifi cantly correlated (RHO=+0.6188 p

Objective Despite the high prevalence of chronic multisite pain, there is little consensus on methods to characterize it. Commonly used assessments report only one dimension of pain, that is, intensity, thus ignoring the spatial aspect of pain. We developed a novel pain quantification index, the Integrated Pain Quantification Index (IPQI), on a scale of 0 to 1 that integrates multiple distinct pain measures into a single value, thus representing multidimensional pain information with a single value. Design Single-visit, noninterventional, epidemiological study. Setting Fourteen outpatient multidisciplinary pain management programs. Patients Patients with chronic pain of the trunk and/or limbs for at least six months with average overall pain intensity of at least 5 on the numeric rating scale. Methods Development of IPQI was performed in a large population (N = 810) of chronic pain patients from the Multiple Areas of Pain (MAP) study. Results Prevalence of two or more noncontiguous painful areas was at 88.3% (95% confidence interval [CI] = 0.86-0.90), with a mean of 6.3 areas (SD = 5.57 areas). Prevalence of more than 10% body area in pain was at 52.8% (95% CI = 0.49-0.56), with a mean at 16.1% (17.16%). On average, IPQI values were near the middle of the scale, with mean and median IPQI at 0.52 (SD = 0.13) and 0.55, respectively. The IPQI was generalizable and clinically relevant across all domains recommended by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials. Conclusions IPQI provided a single pain score for representing complex, multidimensional pain information on one scale and has implications for comparing pain populations across longitudinal clinical trials.

This study evaluated a nurse-delivered, telehealth intervention of cognitive-behavioral therapy (CBT) versus supportive psychotherapy for chronic back pain. Participants (N = 61) had chronic back pain (pain "daily" ≥6 months at an intensity of ≥4 of 10 scale) and were randomized to an 8-week, 12-session, CBT or to supportive care (SC) matched for frequency, format, and time, with each treatment delivered by a primary care nurse. The primary outcome was the Roland Morris Disability Questionnaire (RMDQ). Secondary outcomes included the numeric rating scale (NRS) and the Patient Global Impressions Scale (CGI). CBT participants (n = 30) showed significant improvements on the RMDQ (mean = 11.4 [SD = 5.9] vs 9.4 [SD = 6.1] at baseline and post-treatment, respectively, P .05; d = .33), NRS (mean = 4.9 [SD = 2.1] vs 4.0 [SD = 1.9], respectively, P .05; d = .45), and on the CGI (39.1% reporting "much improved" or "very much improved"). SC participants (n = 31) also showed significant improvements on the RMDQ (mean = 11.1 [SD = 5.4] vs 9.1 [SD = 5.2], respectively, P .05; d = .38), the NRS, (mean = 5.0 [SD = 1.9] vs 3.8 [SD = 2.1], respectively, P .05; d = .60), and 26.7% reporting "much improved" or "very much improved" on the CGI. Between groups comparisons of CBT and SC showed no differences on the study outcomes (Ps.10). The results suggest that telehealth, nurse-delivered CBT, and SC treatments for chronic back pain can offer significant and relatively comparable benefits.This article describes the benefits of training primary care nurses to deliver evidence-based behavioral therapies for low back pain. Because of the high prevalence of chronic pain and the growing emphasis on nonopioid therapies, training nurses to provide behavior therapies could be a cost-effective way to improve pain management.

BackgroundNo prior studies have examined injection pain associated with Technetium-99m Tilmanocept (TcTM).MethodsThis was a randomized, double-blinded study comparing postinjection site pain between filtered Technetium Sulfur Colloid (fTcSC) and TcTM in breast cancer lymphoscintigraphy. Pain was evaluated with a visual analogue scale (VAS) (0-100 mm) and the short-form McGill Pain Questionnaire (SF-MPQ). The primary endpoint was mean difference in VAS scores at 1-min postinjection between fTcSC and TcTM. Secondary endpoints included a comparison of SF-MPQ scores between the groups at 5 min postinjection and construction of a linear mixed effects model to evaluate the changes in pain during the 5-min postinjection period.ResultsFifty-two patients underwent injection (27-fTcSC, 25-TcTM). At 1-min postinjection, patients who received fTcSC experienced a mean change in pain of 16.8 mm (standard deviation (SD) 19.5) compared with 0.2 mm (SD 7.3) in TcTM (p = 0.0002). At 5 min postinjection, the mean total score on the SF-MPQ was 2.8 (SD 3.0) for fTcSC versus 2.1 (SD 2.5) for TcTM (p = 0.36). In the mixed effects model, injection agent (p < 0.001), time (p < 0.001) and their interaction (p < 0.001) were associated with change in pain during the 5-min postinjection period. The model found fTcSC resulted in significantly more pain of 15.2 mm (p < 0.001), 11.3 mm (p = 0.001), and 7.5 mm (p = 0.013) at 1, 2, and 3 min postinjection, respectively.ConclusionsInjection with fTcSC causes significantly more pain during the first 3 min postinjection compared with TcTM in women undergoing lymphoscintigraphy for breast cancer.

A randomized, double-blinded, placebo controlled crossover study was conducted in 16 patients with painful diabetic peripheral neuropathy to assess the short-term efficacy and tolerability of inhaled cannabis. In a crossover design, each participant was exposed to 4 single dosing sessions of placebo or to low (1% tetrahydrocannabinol [THC]), medium (4% THC), or high (7% THC) doses of cannabis. Baseline spontaneous pain, evoked pain, and cognitive testing were performed. Subjects were then administered aerosolized cannabis or placebo and the pain intensity and subjective "highness" score was measured at 5, 15, 30, 45, and 60 minutes and then every 30 minutes for an additional 3 hours. Cognitive testing was performed at 5 and 30 minutes and then every 30 minutes for an additional 3 hours. The primary analysis compared differences in spontaneous pain over time between doses using linear mixed effects models. There was a significant difference in spontaneous pain scores between doses (P.001). Specific significant comparisons were placebo versus low, medium, and high doses (P = .031, .04, and.001, respectively) and high versus low and medium doses (both P.001). There was a significant effect of the high dose on foam brush and von Frey evoked pain (both P.001). There was a significant negative effect (impaired performance) of the high dose on 2 of the 3 neuropsychological tests (Paced Auditory Serial Addition Test, Trail Making Test Part B.This small, short-term, placebo-controlled trial of inhaled cannabis demonstrated a dose-dependent reduction in diabetic peripheral neuropathy pain in patients with treatment-refractory pain. This adds preliminary evidence to support further research on the efficacy of the cannabinoids in neuropathic pain.

Background: Epidural corticosteroid injections are a common treatment for radicular pain caused by intervertebral disc herniations, spinal stenosis, and other disorders. Although rare, catastrophic neurologic injuries, including stroke and spinal cord injury, have occurred with these injections. Methods: A collaboration was undertaken between the U.S. Food and Drug Administration Safe Use Initiative, an expert multidisciplinary working group, and 13 specialty stakeholder societies. The goal of this collaboration was to review the existing evidence regarding neurologic complications associated with epidural corticosteroid injections and produce consensus procedural clinical considerations aimed at enhancing the safety of these injections. U.S. Food and Drug Administration Safe Use Initiative representatives helped convene and facilitate meetings without actively participating in the deliberations or decision-making process. Results: Seventeen clinical considerations aimed at improving safety were produced by the stakeholder societies. Specific clinical considerations for performing transforaminal and interlaminar injections, including the use of nonparticulate steroid, anatomic considerations, and use of radiographic guidance are given along with the existing scientific evidence for each clinical consideration. Conclusion: Adherence to specific recommended practices when performing epidural corticosteroid injections should lead to a reduction in the incidence of neurologic injuries.

In Part One of this two-part series, we discussed skin physiology and anatomy as well as generalities concerning topical analgesics. This modality of therapy has lesser side effects and drug–drug interactions, and patients tolerate this form of therapy better than many oral options. Unfortunately, this modality is not used as often as it could be in chronic pain states, such as that from neuropathic pain. Part Two discusses specific therapies, local anesthetics, and other drugs, as well as how a clinician might use specific aspects of a patient’s neuropathic pain presentation to help guide them in the selection of a topical agent.

© 2014, Society of Surgical Oncology. Methods: Subjects undergoing uni- or bilateral mastectomy received unilateral (n = 24) or bilateral (n = 36) single-injection thoracic paravertebral block(s) with ropivacaine and perineural catheter(s). The subjects were randomized to receive either ropivacaine 0.4 % (n = 30) or normal saline (n = 30) via their catheters until the catheters were removed on postoperative day 3. Chronic pain and pain-related physical and emotional dysfunction were measured using the Brief Pain Inventory (BPI).Background: In a previous randomized, triple-masked, placebo-controlled study, the authors demonstrated that extending a single-injection paravertebral nerve block with a multiple-day perineural local anesthetic infusion improves analgesia and decreases pain-related dysfunction during the 3-day infusion but not subsequent to catheter removal within 1 month after mastectomy. This report describes a prospective follow-up study of the previously published trial to investigate the possibility that extending a single-injection paravertebral block with a multiple-day infusion may decrease persistent postsurgical pain as well as pain-induced emotional and functional dysfunction 1 year after mastectomy.Results: No statistically significant difference between treatments 3 months after surgery was observed with the BPI. In contrast, after 12 months, only 4 subjects (13 %) who had received a perineural ropivacaine infusion reported pain-induced dysfunction compared with 14 (47 %) who had received saline infusion (P = 0.011). At 12 months, the mean BPI was 1.6 ± 4.6 for the subjects who received ropivacaine versus 5.9 ± 11.3 for the subjects who received saline (P = 0.007).Conclusions: Adding a multiple-day, continuous ropivacaine infusion to a single-injection ropivacaine paravertebral nerve block may result in a lower incidence of pain as well as pain-related physical and emotional dysfunction 1 year after mastectomy.

Background and Objectives We evaluated the infusion accuracy and device-related safety of implantable drug infusion pumps in subjects with chronic pain or severe spasticity. Methods Nine centers in the United States enrolled patients receiving intrathecal drug delivery systems to manage chronic pain and/or severe spasticity. Infusion accuracy was assessed at 6 and 12 months by comparing syringe-measured delivered volumes to programmer-predicted volumes. Safety was evaluated through analysis of adverse events. Separate laboratory testing conducted by the manufacturer also evaluated infusion accuracy. Results Eighty of 82 enrolled subjects were implanted. Sixty-five and 54 subjects, respectively, were analyzable for accuracy at 6 and 12 months. On average at 6 months, the pumps were measured to have delivered 1% more than the programmed delivery volume. Analyzed on a per-refill basis, the pumps delivered, on average, 2.5% more than the programmed delivery volume. Differences between per-refill means versus per-subject cumulative means were due to limitations in clinicians’ ability to precisely visualize single small syringe-volume differences, or possibly incomplete withdrawal of fluid from the pump. Laboratory testing demonstrated a per-refill mean accuracy error of minus 2.4%. Because average observed flow-rate error at 6 and 12 months (1% overinfusion) was derived from pump residual volume measurements by syringe and carried out in a clinical setting, clinical volume ratios were larger than direct volume measurements by weight observed in the laboratory. No deaths, permanent injuries, or unanticipated adverse device effects occurred. Conclusions The pump accurately delivered intrathecal medication in the clinical setting of this study. Adverse events were similar in nature and severity to those described in the product labeling and literature.

The intradermal capsaicin pain model has been used to evaluate analgesic effects of a variety of drugs. Using the sequential up-down method, we examined the analgesic effects of pregabalin on intradermal capsaicin pain. Using a double-blind, placebo-controlled, crossover study, healthy adult men were randomized to oral pregabalin or placebo on the first visit and returned for the opposite treatment after a washout period. Dosing was set by the Dixon sequential up-down method; that is, a greater or less than 30% reduction in capsaicin pain decreased or increased the dose, respectively, by a fixed interval for the next subject. The median effective dose (ED50) was derived once 7 changes in dose direction occurred. Secondary outcome measures included secondary hyperalgesia and tactile and thermal allodynia, and their respective areas (cm 2 ). Thirteen subjects were required to derive the pregabalin ED50: 252 mg (95% confidence interval 194, 310 mg). Most common side effects were drowsiness (46%), euphoria (31%), and dizziness (7%). Those with ≥30% pain reduction as compared to placebo also had similar reductions in secondary outcome measures. The intradermal capsaicin pain model can be used to efficiently derive the pregabalin ED50, but well-powered dose-response curve studies are needed for comparison and validation. Perspective Using the Dixon sequential up-down method, the ED50 of pregabalin on intradermal capsaicin induced pain was successfully calculated (252 mg) using only 13 subjects.

BACKGROUND: We aimed to determine with this randomized, triple-masked, placebo-controlled study if benefits are afforded by adding a multiple-day, ambulatory, continuous ropivacaine paravertebral nerve block to a single-injection ropivacaine paravertebral block after mastectomy. METHODS: Preoperatively, 60 subjects undergoing unilateral (n = 24) or bilateral (n = 36) mastectomy received either unilateral or bilateral paravertebral perineural catheter(s), respectively, inserted between the third and fourth thoracic transverse process(es). All subjects received an initial bolus of ropivacaine 0.5% (15 mL) via the catheter(s). Subjects were randomized to receive either perineural ropivacaine 0.4% or normal saline using portable infusion pump(s) [5 mL/h basal; 300 mL reservoir(s)]. Subjects remained hospitalized for at least 1 night and were subsequently discharged home where the catheter(s) were removed on postoperative day (POD) 3. Subjects were contacted by telephone on PODs 1, 4, 8, and 28. The primary end point was average pain (scale, 0-10) queried on POD 1. RESULTS: Average pain queried on POD 1 for subjects receiving perineural ropivacaine (n = 30) was a median (interquartile) of 2 (0-3), compared with 4 (1-5) for subjects receiving saline (n = 30; 95% confidence interval difference in medians, -4.0 to -0.3; P = 0.021]. During this same period, subjects receiving ropivacaine experienced a lower severity of breakthrough pain (5 [3-6] vs 7 [5-8]; P = 0.046) as well. As a result, subjects receiving perineural ropivacaine experienced less pain-induced physical and emotional dysfunction, as measured with the Brief Pain Inventory (lower score = less dysfunction): 14 (4-37) versus 57 (8-67) for subjects receiving perineural saline (P = 0.012). For the subscale that measures the degree of interference of pain on 7 domains, such as general activity and relationships, subjects receiving perineural saline reported a median score 10 times higher (more dysfunction) than those receiving ropivacaine (3 [0-24] vs 33 [0-44]; P = 0.035). In contrast, after infusion discontinuation, there were no statistically significant differences detected between treatment groups. CONCLUSIONS: After mastectomy, adding a multiple-day, ambulatory, continuous ropivacaine infusion to a single-injection ropivacaine paravertebral nerve block results in improved analgesia and less functional deficit during the infusion. However, no benefits were identified after infusion discontinuation. Copyright © 2014 by American Society of Regional Anesthesia and Pain.

Experimental interventions that activate specific components of clinical pain are necessary for characterization of underlying mechanisms and pharmacology. Cutaneous hyperalgesia has been described that uses non-painful heat to induce secondary hyperalgesia. This study evaluated the effect intravenous alfentanil on experimental cutaneous hyperalgesia created using this method. Eighteen subjects participated in a randomized, double-blinded, placebo controlled crossover study consisting of two sessions, one with alfentanil and one with placebo. Using a computer-controlled infusion pump, alfentanil or matching placebo was maintained at a constant plasma level of 75 ng/ml for one hour followed by the application of a 40° C heat stimulus to the right thenar eminence for 15 minutes. The temperature was raised by 1° C every 15 minutes until the subject reported pain or 45° C was reached. After the end point was reached, the temperature was maintained and repeat testing was performed. The non-painful heat created an area of secondary cutaneous hyperalgesia and significant decrease in mechanical pain threshold on heat-treated right versus untreated left during placebo administration. Alfentanil prevented the hypersensitivity when compared to placebo (p

Nearly all who review the literature conclude that the role of invasive procedures to treat chronic pain is poorly characterized because of the lack of “definitive” studies. The overt nature of invasive treatments, along with the risks, technical skills, and costs involved create challenges to study them. However, these challenges do not completely preclude evaluating invasive procedure effectiveness and safety using well-designed methods. This article reviews the challenges of studying outcomes of invasive therapies to treat pain and discuss possible solutions. Although the following discussion can apply to most invasive therapies to treat chronic pain, it is beyond the scope of the article to individually cover every invasive therapy used. Therefore, most of the examples focus on injection therapies to treat spine pain, spinal cord stimulation, and intrathecal drug therapies.

Supplemental Digital Content is Available in the Text., Pain is an experience that affects many people worldwide and is associated with higher mortality and lower quality of life. Cannabinoid, cannabis, and cannabis-based medicines (CBMs) are thought to reduce pain, but a proliferation of different products has led to variability in trials, creating a challenge when determining the assessment of efficacy in systematic reviews. We will conduct 2 systematic reviews commissioned by the International Association for the Study of Pain Task Force on the use of cannabinoids, cannabis, and CBMs for pain management: first, an overview review of systematic reviews to summarise the evidence base and second, a systematic review of randomised controlled trials of cannabinoids, cannabis, and CBMs. In these reviews we will determine the harm and benefit of CBM from the current literature and will interpret the findings in light of the quality of evidence and reviews included. We will search online databases and registries in any language for systematic reviews and randomised controlled trials. We will include studies that evaluate any cannabinoid or CBM vs any control for people with acute and chronic pain. Our primary outcomes for both reviews are the number of participants achieving (1) a 30% and (2) 50% reduction in pain intensity, (3) moderate improvement, and (4) substantial improvement. A number of secondary outcome measures will also be included. We will assess risk of bias and quality of evidence. We will analyse data using fixed and random effect models, with separate comparators for cannabis and CBMs. Prospero ID (CRD42019124710; CRD42019124714).

During the past decade, Cannabis derivatives in pain medicine have been of increasing interest. Specifically, the non-psychoactive Cannabidiol (CBD) has received recent attention. CBD has been used as a treatment for childhood epilepsy, chronic pain, and anxiety disorders, and presents a unique situation in healthcare: patients may be more familiar with it than their physician. We asked patients and staff in the environment of seven pain clinics in Southern California about their knowledge, beliefs, and personal experience surrounding CBD products. After IRB review (exempt status) we utilized the internet survey platform SurveyMonkey to administer the survey online. Our participants were 45.26±14.02 (Mean±SD) years old, the majority identified as white, has an annual household income of less than $20,000, and is insured by Medicare or Medicaid. Among our participants, 63% report to have tried a CBD product (including products containing THC) and 37.30% of these answered that the used CBD product did not contain THC. Of these, the majority responded that CBD products have helped their condition (57.45%) and reduced their pain medication (61.7%), including opioids (44.68%). Among the pain conditions patients reported relieve were back pain (63.83%), nerve pain (38.30%), neck pain (38.30%), migraines (29.79%), limb pain (19.15%), fibromyalgia (19.15%), and other (19.15%). Overall, participants familiarity with the dosing of their CBD product varied. Generally, participants believe CBD is a good treatment option, and not harmful. The overall attitude and experience of participants regarding CBD products was positive and CBD only was reported to reduce pain medication, including opioids. With the voluntary nature of a survey design come some study limitations that warrant attention. However, studies like this can help identify areas of interest for future research and more controlled research has to follow. Supported by a grant from Versea Pharmaceuticals

Treatment options for postherpetic neuralgia (PHN), a complication of herpes zoster, are commonly unsatisfactory and associated with adverse events.To evaluate the efficacy, onset of pain relief, and safety of gastroretentive gabapentin (G-GR) in patients with PHN.In two placebo-controlled studies, 357 patients with PHN were randomized to 1800mg G-GR and 364 patients were randomized to placebo taken with the evening meal. Patients underwent a two week titration, eight weeks of stable dosing, and one week of tapering. Efficacy assessments included change in average daily pain (ADP) score from baseline to Week 10, time to onset of pain relief, the proportion of patients feeling improved using the Patient Global Impression of Change, and the proportion of responders (≥30% pain reduction).At Week 10, patients randomized to G-GR reported greater reductions in ADP score compared with placebo (-37.0% vs. -29.1; P=0.0025). More G-GR patients felt improved compared with placebo (44% vs. 33%; P=0.003) and responded to treatment (54% vs. 41%; P=0.001). As early as Day 2, greater pain reductions were observed for the G-GR group compared with the placebo group (-6.6% vs. -1.6%; P=0.0017). The median time to a one point or greater reduction in ADP score was four days for G-GR and six days for placebo (P0.0001). The most frequently reported adverse events were dizziness (G-GR, 11%; placebo, 2%) and somnolence (G-GR, 5%; placebo, 3%).PHN pain reduction after G-GR treatment can be observed as early as the second day of dosing and continues for at least 10 weeks.

Objective The education of physicians is a fundamental obligation within medicine that must remain closely aligned with clinical care. And although medical education in pain care is essential, the current state of medical education does not meet the needs of physicians, patients, or society. To address this, we convened a committee of pain specialist medical student educators. Methods Tasked with creating systematically developed and valid recommendations for clinical education, we conducted a survey of pain medicine leadership within the American Academy of Pain Medicine (AAPM). The survey was conducted in two waves. We asked AAPM board members to rate 194 previously published pain medicine learning objectives for medical students; 79% of those eligible for participation responded. Results The “Top 5” list included the awareness of acute and chronic pain, skillfulness in clinical appraisal, promotion of compassionate practices, displaying empathy toward the patient, and knowledge of terms and definitions for substance abuse. The “Top 10” list included the major pharmacological classes as well as skills in examination, communication, prescribing, and interviewing. The “Top 20” list included the pain care of cognitively impaired populations, those with comorbid illness, and older adults. With the survey results in consideration, the committee produced a new recommended topic list for curricula in pain medicine. We strongly recommend that adequate resources are devoted to fully integrated medical curricula in pain so that students will learn not only the necessary clinical knowledge but also be prepared to address the professional, personal, and ethical challenges that arise in caring for those with pain. Conclusions We conclude that improved medical education in pain is essential to prepare providers who manifest both competence and compassion toward their patients.

Background Non-N-methyl-D-aspartate receptor subtypes modulate neurotransmitter release and mediate fast excitatory postsynaptic potentials. This study evaluated the effects of an oral prodrug to tezampanel, a selective α-amino-3-hydroxy-5-methly-4-isoxazole-proprionic acid/kainate receptor antagonist, on intradermal capsaicin-induced pain and hyperalgesia. Methods This was a randomized, double blind, crossover, placebo-controlled study. Eighteen subjects received 150 or 90 mg NGX426, or placebo, separated by a washout of 6 ± 2 days. In each treatment period, two intradermal injections of capsaicin were given in the volar region of alternate forearms at 30- and 120-minute drug/placebo administration. Spontaneous pain, elicited pain, and area of hyperalgesia were determined at certain time points after each injection. Subjects were asked to rate the painfulness of a 1-minute long 45°C heat stimulus (brief thermal stimulation [BTS]) applied to the anterior thigh at 4 hours and 30 minutes following drug administration, then every 30 minutes through 6 hours following drug administration. Results The 150-mg dose produced a statistically definitive reduction in spontaneous pain for all time points relative to placebo. The 90-mg dose produced a statistically significant reduction for the early time point and the entire time interval. Both doses significantly reduced elicited pain at all time points. For the BTS, the 150-mg group reached statistical significance compared with placebo at the 270-minute time point only. Conclusions This study demonstrated that NGX426 reduces capsaicin-induced pain and hyperalgesia in human volunteers with low incidence of side effects that suggests that this class of drug may be effective in the treatment of clinical pain.

Retrospective studies have associated perioperative regional anesthesia/analgesia during mastectomy for breast cancer with a decreased incidence of cancer recurrence. However, to date, no prospective data from a randomized controlled trial have been reported. In a previous study we found that extending a single-injection paravertebral block with a multiple-day perineural local anesthetic infusion improves analgesia. This follow-up study investigates the rates of cancer recurrence for the single-injection and multiple-day infusion treatments. Patients undergoing unilateral (n = 24) or bilateral mastectomy (n = 36) were included in the study. All patients had been diagnosed with breast cancer or tumor in situ, except for six patients who were receiving prophylactic bilateral mastectomy and were excluded from analyses. Patients received unilateral or bilateral single-injection thoracic paravertebral block(s) corresponding to their surgical site(s) with ropivacaine and perineural catheter(s). Subsequently, patients were randomized to receive either ropivacaine 0.4% (n = 30) or normal saline (n = 30) via their catheter(s) until catheter removal on postoperative day 3. Cancer recurrence from the date of surgery until at least 2 years post surgery was investigated via chart review. Five of the 54 (9.2%) patients experienced a cancer recurrence following mastectomy—3 of 26 (11.5%) of the patients with perineural ropivacaine and 2 of 28 (7.1%) of the patients with perineural saline. This pilot study found no evidence that extending a single-injection paravertebral block with a multi-day perineural local anesthetic infusion decreases the risk of post-mastectomy cancer recurrence. However, due to the small sample size of this investigation, further research is needed to draw definitive conclusions.