Summary
Background
Endogenous pain modulation (EPM) reflects the brain's ability to modulate incoming nociceptive inputs, and deficient EPM was implicated as a chronic pain mechanism. EPM status has ...been investigated in temporomandibular disorders (TMD) patients with conflicting results, and its relationship with clinical characteristics in this population is not well known.
Objectives
(a) Determine EPM responses in chronic TMD cases and pain‐free controls; (b) Derive pain modulation profiles (PMP) based on individual EPM responses; and (c) Categorise clinical characteristics of TMD cases and pain‐free controls based on their individual PMP.
Methods
Twenty‐two chronic TMD cases and 17 age‐matched pain‐free controls, all females, were comprehensively characterised regarding clinical characteristics and underwent EPM testing using temporal summation of pain (TSP) and conditioned pain modulation (CPM) protocols over the face and hand. Individuals were categorised into PMPs (I‐IV) based on predetermined cut‐off points for TSP and CPM responses.
Results
Between‐group comparisons showed similar TSP and CPM responses (P > 0.23) in the face, while TMD cases showed significantly increased TSP (P = 0.04) but similar CPM responses (P > 0.17) in the hand relative to controls. Similar distribution across PMPs and clinical characteristics when categorised into PMPs was found for both groups. Body mass index was associated with increased TSP and reduced CPM in the face in TMD cases.
Conclusion
Endogenous pain modulation responses over the face were similar between groups. TMD cases showed increased hand TSP compared to controls while both groups showed no significant hand CPM. PMP classification showed similar results between groups, and further refinement of PMP determination is warranted.
The American Society of Regional Anesthesia and Pain Medicine (ASRA) 2012 survey of meeting attendees showed that existing ASRA anticoagulation guidelines for regional anesthesia were insufficient ...for their needs. Those surveyed agreed that procedure-specific and patient-specific factors required separate guidelines for pain and spine procedures. In response, a guidelines committee was formed. After preliminary review of published complications reports and studies, the committee stratified interventional spine and pain procedures according to potential bleeding risk: low-, intermediate-, and high-risk procedures. The ASRA regional anesthesia anticoagulation guidelines were largely deemed appropriate for the low- and intermediate-risk categories, but the high-risk category required further investigation. The first guidelines specific to interventional spine and pain procedures were published in 2015. Recent reviews evaluating bleeding complications in patients undergoing specific interventional pain procedures, the development of new regional anesthesia and acute pain guidelines, and the development of new anticoagulants and antiplatelet medications necessitate complementary updated guidelines. The authors desired coordination with the authors of the recently updated regional and acute pain anticoagulation guidelines. The latest evidence was sought through extensive database search strategies and the recommendations were evidence based when available and pharmacology driven otherwise. We could not provide strength and grading of these recommendations because there are not enough well-designed large studies concerning interventional pain procedures to support such grading. Although the guidelines could not always be based on randomized studies or on large numbers of patients from pooled databases, it is hoped that they will provide sound recommendations and the evidentiary basis for such recommendations. This publication is intended as a living document to be updated periodically with consideration of new evidence.
Chronic pain exerts an enormous personal and economic burden, affecting more than 30% of people worldwide according to some studies. Unlike acute pain, which carries survival value, chronic pain ...might be best considered to be a disease, with treatment (eg, to be active despite the pain) and psychological (eg, pain acceptance and optimism as goals) implications. Pain can be categorised as nociceptive (from tissue injury), neuropathic (from nerve injury), or nociplastic (from a sensitised nervous system), all of which affect work-up and treatment decisions at every level; however, in practice there is considerable overlap in the different types of pain mechanisms within and between patients, so many experts consider pain classification as a continuum. The biopsychosocial model of pain presents physical symptoms as the denouement of a dynamic interaction between biological, psychological, and social factors. Although it is widely known that pain can cause psychological distress and sleep problems, many medical practitioners do not realise that these associations are bidirectional. While predisposing factors and consequences of chronic pain are well known, the flipside is that factors promoting resilience, such as emotional support systems and good health, can promote healing and reduce pain chronification. Quality of life indicators and neuroplastic changes might also be reversible with adequate pain management. Clinical trials and guidelines typically recommend a personalised multimodal, interdisciplinary treatment approach, which might include pharmacotherapy, psychotherapy, integrative treatments, and invasive procedures.
Purpose of Review
The development of acute to chronic pain involves distinct pathophysiological changes in the peripheral and central nervous systems. This article reviews the mechanisms, etiologies, ...and management of chronic pain syndromes with updates from recent findings in the literature.
Recent Findings
Chronic post-surgical pain (CPSP) is not limited to major surgeries and can develop after smaller procedures such as hernia repairs. While nerve injury has traditionally been thought to be the culprit for CPSP, it is evident that nerve-sparing surgical techniques are not completely preventative. Regional analgesia and agents such as ketamine, gabapentinoids, and COX-2 inhibitors have also been found to decrease the risks of developing chronic pain to varying degrees. Yet, given the correlation of central sensitization with the development of chronic pain, it is reasonable to utilize aggressive multimodal analgesia whenever possible.
Summary
Development of chronic pain is typically a result of peripheral and central sensitization, with CPSP being one of the most common presentations. Using minimally invasive surgical techniques may reduce the risk of CPSP. Regional anesthetic techniques and preemptive analgesia should also be utilized when appropriate to reduce the intensity and duration of acute post-operative pain, which has been correlated with higher incidences of chronic pain.
The effects of altered neural processing, defined as altering neural networks responsible for perceptions of pain and function, on chronic pain remains unclear.
To estimate the effect of a graded ...sensorimotor retraining intervention (RESOLVE) on pain intensity in people with chronic low back pain.
This parallel, 2-group, randomized clinical trial recruited participants with chronic (>3 months) nonspecific low back pain from primary care and community settings. A total of 276 adults were randomized (in a 1:1 ratio) to the intervention or sham procedure and attention control groups delivered by clinicians at a medical research institute in Sydney, Australia. The first participant was randomized on December 10, 2015, and the last was randomized on July 25, 2019. Follow-up was completed on February 3, 2020.
Participants randomized to the intervention group (n = 138) were asked to participate in 12 weekly clinical sessions and home training designed to educate them about and assist them with movement and physical activity while experiencing lower back pain. Participants randomized to the control group (n = 138) were asked to participate in 12 weekly clinical sessions and home training that required similar time as the intervention but did not focus on education, movement, and physical activity. The control group included sham laser and shortwave diathermy applied to the back and sham noninvasive brain stimulation.
The primary outcome was pain intensity at 18 weeks, measured on an 11-point numerical rating scale (range, 0 no pain to 10 worst pain imaginable) for which the between-group minimum clinically important difference is 1.0 point.
Among 276 randomized patients (mean SD age, 46 14.3 years; 138 50% women), 261 (95%) completed follow-up at 18 weeks. The mean pain intensity was 5.6 at baseline and 3.1 at 18 weeks in the intervention group and 5.8 at baseline and 4.0 at 18 weeks in the control group, with an estimated between-group mean difference at 18 weeks of -1.0 point (95% CI, -1.5 to -0.4; P = .001), favoring the intervention group.
In this randomized clinical trial conducted at a single center among patients with chronic low back pain, graded sensorimotor retraining, compared with a sham procedure and attention control, significantly improved pain intensity at 18 weeks. The improvements in pain intensity were small, and further research is needed to understand the generalizability of the findings.
ANZCTR Identifier: ACTRN12615000610538.
Low back pain is one of the most prevalent musculoskeletal conditions and the highest contributor to disability in the world. It is characterized by frequent relapses leading to additional ...care-seeking. Engagement in leisure physical activity is associated with lower recurrences and better prognosis and potentially reduced care-seeking. Our aim was to investigate the feasibility and preliminary efficacy of a patient-centred physical activity intervention, supported by health coaching and mobile health, to reduce care-seeking, pain and disability in patients with chronic low back pain after treatment discharge.
We conducted a pilot randomised controlled trial with blinded outcome assessment. Sixty-eight participants were recruited from four public outpatient physiotherapy departments and the general community in Sydney. The intervention group received a physical activity information booklet, plus one face-to-face and 12 telephone-based health coaching sessions. The intervention was supported by an internet-based application and an activity tracker (Fitbit). Control group (standard care) received the physical activity information booklet and advice to stay active. Feasibility measures included recruitment rate, intervention compliance, data completeness, and participant satisfaction. Primary outcomes were care-seeking, pain levels and activity limitation. Outcomes were assessed at baseline, 6-month follow-up and weekly for 6 months.
Ninety potential participants were invited over 15 months, with 68 agreeing to take part (75%). Overall, 903 weekly questionnaires were answered by participants from a total of 1107 sent (89%). Participants were largely satisfied with the intervention (mean = 8.7 out of 10 on satisfaction scale). Intervention group participants had a 38% reduced rate of care-seeking (Incidence Rate Ratio (IRR): 0.62, 95% CI: 0.32 to 1.18, p = 0.14, using multilevel mixed-effects Poisson regression analysis) compared to standard care, although none of the estimates was statistically significant. No between groups differences were found for pain levels or activity limitation.
The health coaching physical activity approach trialed here is feasible and well accepted by participants and may reduce care-seeking in patients with low back pain after treatment discharge, although further evaluation with an adequately powered trial is needed.
Australian and New Zealand Trial Registry ACTRN12615000189527 . Registered prospectively on 26-02-2015.
The role of psychosocial and physical factors in the development of musculoskeletal pain (MSP) has now been clearly demonstrated. However, it is unclear whether these factors contribute to specific ...regional MSP or to multisite pain. The main goal of this study was to assess the impact of work-related factors according to gender on the development of regional and multisite MSP. A total of 12,591 subjects (65% men and 35% women) who were born in 1938, 1943, 1948, and 1953 and were participating in a French longitudinal prospective epidemiological survey (ESTEV) in 1990 to 1995 were eligible. Personal factors and work exposure were assessed by self-administered questionnaires. Statistical associations between chronic MSP (regional body site or multisite), personal factors, and occupational factors were analyzed using logistic regression modeling. The incidence of regional MSP and multisite pain in 1995 were, respectively, 17% and 25.6%. For women, highly repetitive movements predicted neck/shoulder pain; posture and vibrations predicted arm and low back pain; and effort with tools predicted arm pain. For men, forceful effort and vibrations predicted neck/shoulder pain; posture and forceful effort predicted lower limb and low back pain; and forceful effort and effort with tools predicted arm pain. Physical constraints (ie, forceful effort or vibrations) were associated with multisite pain in both genders. Only for women, psychological factors were risk factors predictive of upper limb pain and in 3 or 4 painful anatomical sites. These results support the hypothesis that some physical and psychological work-related factors are predictive of regional or multisite MSP but differ according to gender. Gender differences and risk factors for work-related musculoskeletal pain should be also taken into account to more effectively target preventive measures.
Neuropathic pain can develop after nerve injury, when deleterious changes occur in injured neurons and along nociceptive and descending modulatory pathways in the central nervous system. The myriad ...neurotransmitters and other substances involved in the development and maintenance of neuropathic pain also play a part in other neurobiological disorders. This might partly explain the high comorbidity rates for chronic pain, sleep disorders, and psychological conditions such as depression, and why drugs that are effective for one condition may benefit others. Neuropathic pain can be distinguished from non-neuropathic pain by two factors. Firstly, in neuropathic pain there is no transduction (conversion of a nociceptive stimulus into an electrical impulse). Secondly, the prognosis is worse: injury to major nerves is more likely than injury to non-nervous tissue to result in chronic pain. In addition, neuropathic pain tends to be more refractory than non-neuropathic pain to conventional analgesics, such as non-steroidal anti-inflammatory drugs and opioids. However, because of the considerable overlap between neuropathic and nociceptive pain in terms of mechanisms and treatment modalities, it might be more constructive to view these entities as different points on the same continuum. This review focuses on the mechanisms of neuropathic pain, with special emphasis on clinical implications.
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