Pain medicine basics: Overview

Neuromodulation: Technology at the Neural Interface is the preeminent journal in the area of neuromodulation, providing our readership with the state of the art clinical, translational and basic science research in our field and representing the needs of the broad neuromodulation community. For clinicians, engineers, scientists and members of the biotechnology industry alike, Neuromodulation provides timely and rigorously peer reviewed articles on the technology, science and clinical application of devices that interface with the nervous system to treat disease and improve function. Neuromodulation covers an ever expanding field including pain, headache, movement disorders, spasticity, paralysis, psychiatric disorders, epilepsy, sensory deprivation, gastric dysfunction, obesity and incontinence.

Regional Anesthesia & Pain Medicine, the official publication of the American Society of Regional Anesthesia and Pain Medicine (ASRA Pain Medicine), is a monthly journal that publishes peer-reviewed scientific and clinical studies to advance the understanding and clinical application of regional techniques for surgical anesthesia and postoperative analgesia. Coverage includes intraoperative regional techniques, perioperative pain, chronic pain, obstetric anesthesia, paediatric anesthesia, outcome studies, and complications.

Abstract
Purpose: Evaluate benefits and harms of education/advice for chronic primary low back pain (CPLBP) in adults to inform a World Health Organization (WHO) standard clinical guideline.

Methods: Electronic databases were searched for randomized controlled trials (RCTs) assessing education/advice compared with placebo/sham, usual care, or no intervention (including comparison interventions where the attributable effect of education/advice could be isolated). We conducted meta-analyses and graded the certainty of evidence.

Results: We screened 2514 citations and 86 full text RCTs and included 15 RCTs. Most outcomes were assessed 3 to 6 months post-intervention. Compared with no intervention, education/advice improved pain (10 RCTs, MD = -1.1, 95% CI -1.63 to -0.56), function (10 RCTs, SMD = -0.51, 95% CI -0.89 to -0.12), physical health-related quality of life (HRQoL) (2 RCTs, MD = 24.27, 95% CI 12.93 to 35.61), fear avoidance (5 RCTs, SMD = -1.4, 95% CI -2.51 to -0.29), depression (1 RCT; MD = 2.10, 95% CI 1.05 to 3.15), and self-efficacy (1 RCT; MD = 4.4, 95% CI 2.77 to 6.03). Education/advice conferred less benefit than sham Kinesio taping for improving fear avoidance regarding physical activity (1 RCT, MD = 5.41, 95% CI 0.28 to 10.54). Compared with usual care, education/advice improved pain (1 RCT, MD = -2.10, 95% CI -3.13 to -1.07) and function (1 RCT, MD = -7.80, 95% CI -14.28 to -1.32). There was little or no difference between education/advice and comparisons for other outcomes. For all outcomes, the certainty of evidence was very low.

Conclusion: Education/advice in adults with CPLBP was associated with improvements in pain, function, HRQoL, and psychological outcomes, but with very low certainty.

Abstract
Background: Opioid dose titration is a fundamental process of opioid therapy in cancer pain.

Aims: To assess data opioid dose titration.

Methods: The principal opioid dose titration methods, outcomes, and modalities of administration regarding the different opioid preparations were examined in different clinical contexts.

Results: Most studies suggested that opioid-naive patients should be started at doses of 15-30 mg/day of oral morphine equivalents. Opioid-tolerant patients may receive low or higher doses of oral morphine equivalents, depending on the level of opioid tolerance. Generally, dose increments of 30%-50% seem to be indicated to start dose titration. Some patients with severe excruciating cancer pain may present as an emergency requiring a rapid application of powerful analgesic strategies. The intravenous use of opioids may circumvent this problem providing a faster pain relief, due to the large availability and rapid achievement of effective plasma concentrations.

Discussion: Opioid dose titration is a delicate passage in patients with cancer pain. This approach may be different according to different clinical conditions. Opioid dose titration requires expertise to optimize cancer pain management while minimizing the development of adverse effects.

Conclusion: While most approaches are meaningful and partially supported by existing literature, more studies are necessary to establish advantages and disadvantages in different clinical conditions. Optimization of opioid dose titration is of paramount importance.

Significance: This review provides the most recent insights on the different modalities of opioid dose titration in cancer pain management.

Abstract in English, French
Purpose: In children, the relationship between the dose of intraoperative opioid and postoperative outcomes is unclear. We examined the relationship between intraoperative opioid dose and postanesthesia care unit (PACU) pain scores and opioid and antiemetic administrations.

Methods: We performed a single-institution retrospective cohort study. Patients who were aged < 19 yr, had an American Society of Anesthesiologists Physical Status of I-III, were undergoing one of 11 procedures under general anesthesia and without regional anesthesia, and who were admitted to the PACU were included. Patients were analyzed by quartiles of total intraoperative opioid dose using multivariable regression, adjusting for confounders including procedure. An exploratory analysis of opioid-free anesthetics was also performed.

Results: Three thousand, seven hundred and thirty-three cases were included, and the mean age of included patients was 8.3 yr. After adjustment, there were no significant differences between the lowest and higher quartiles for first conscious pain score, mean pain score, PACU opioid dose, or PACU length of stay; in addition, estimated differences were small. Patients in higher quartiles were estimated to be more likely to receive antiemetics, significantly so for those in the second quartile. Patients in the lowest quartile received significantly more intraoperative nonopioid analgesics. In the exploratory analysis, no significant difference in PACU pain scores was found in cases without intraoperative opioids.

Conclusions: Children who received lower doses of intraoperative opioids did not have worse PACU pain outcomes but required fewer antiemetics and received greater numbers of nonopioid analgesics intraoperatively. These findings suggest that lower doses of intraoperative opioids may be administered to children as long as other analgesics are used.

Abstract
Persistent pain is a major public health issue - estimated to affect a quarter of the world's population. Public understanding of persistent pain is based on outdated biomedical models, laden with misconceptions that are contrary to best evidence. This understanding is a barrier to effective pain management. Thus, there have been calls for public health-based interventions to address these misconceptions. Previous pain focussed public education campaigns have targeted pain beliefs and behaviours that are thought to promote recovery, such as staying active. However, prevailing pain-related misconceptions render many of these approaches counter-intuitive, at best. Pain Science Education improves understanding of 'how pain works' and has been demonstrated to improve pain and disability outcomes. Extending Pain Science Education beyond the clinic to the wider community seems warranted. Learning from previous back pain-focussed and other public health educational campaigns could optimise the potential benefit of such a Pain Science Education campaign. Pain Science Education-grounded campaigns have been delivered in Australia and the UK and show promise, but robust evaluations are needed before any firm conclusions on their population impact can be made. Several challenges exist going forward. Not least is the need to ensure all stakeholders are involved in the development and implementation of Pain Science Education public messaging campaigns. Furthermore, it is crucial that campaigns are undertaken through a health equity lens, incorporating underrepresented communities to ensure that any intervention does not widen existing health inequalities associated with persistent pain. PERSPECTIVE: Public misconceptions about pain are a significant public health challenge and a viable intervention target to reduce the personal, social, and economic burden of persistent pain. Adaptation of Pain Science Education, which improves misconceptions in a clinical setting, into the public health setting seems a promising approach to explore.