Psychological and psychosocial predictors of chronic postsurgical pain: a systematic review and meta-analysis

Prevalence and risk factors of chronic postsurgical pain after lung cancer surgery and knee arthroplasty: a prospective multicenter cohort study in Japan

PURPOSE

Chronic postsurgical pain (CPSP) is being increasingly recognized as an important clinical problem. The purpose of this prospective multicenter study was to evaluate the prevalence and risk factors of CPSP at 3 months after surgery in a Japanese population.

METHODS

Adult patients who underwent lung cancer surgery (L) or knee arthroplasty (K) at university hospitals in Japan and provided informed consent were included. Perioperative demographic, clinical, and psychological data were collected. Postsurgical pain scores were assessed via face-to-face interviews at each time point. We also investigated analgesic use at each time point in patients with CPSP.

RESULTS

A total of 494 (L) and 194 (K) patients completed our interviews at all visits up to 3 months after surgery. The prevalence of clinically relevant CPSP was 10% (L) and 28% (K), respectively. In both cohorts, pain intensity at 1 month after surgery was moderately correlated with pain intensity at 3 months after surgery. Multivariate logistic regression analysis revealed significant associations between preoperative chronic pain, current smoking status, and open thoracotomy with CPSP in the lung cohort. However, no pre- or intraoperative risk factors were identified in the knee cohort. None of the CPSP patients used strong opioids.

CONCLUSIONS

The prevalence of CPSP after lung cancer surgery and knee arthroplasty among Japanese patients was comparable with prevalences previously reported in other countries. Subacute pain was significantly correlated with CPSP; however, further studies are needed to determine whether intensive treatment of subacute postsurgical pain can prevent the development of CPSP.

Current state of psychological therapies for children and adults with chronic pain: Where next?

Pain is influenced by biological, psychological and social factors. Whilst analgesics are often prescribed for chronic pain, they provide little benefit for most patients. Psychological therapies manage pain and disability in children and adults with chronic pain. Evidence for cognitive behavioural therapies is the most robust in the field, although benefits are modest. Technological innovation has led to Internet-delivered therapies, but innovation in research often lags behind technological developments due to funding and regulation. Despite the promising outlook, critical gaps in our knowledge of how to manage pain need addressing for both adults and children and their parents. Here we summarise the evidence base of psychological therapies using Cochrane reviews, gaps, and the role of preventing chronic pain onset.

Patients' experiences of living with Long Covid and their beliefs about the role of psychology in their condition

Some patients with chronic conditions are unreceptive to a psychological approach. This study aimed to explore the experience of Long Covid (LC) with an emphasis on patients' beliefs about the role of psychology. UK participants (n = 14) with either self-reported or diagnosed LC took part in semi-structured interviews. Thematic analysis described three main themes: 'Living in uncertainty', 'Why should I trust you if you don't believe me?' and 'Once I know the cause people will believe me'. Transcending these themes was a tension between professional experts and experts by lived experience and a dichotomy between psychological and medical explanations. Overarching all themes was a sense that synthesising the biological and psychological components of LC could help to resolve this tension. In summary. living with LC is characterised by feeling disbelieved which can drive the rejection of psychology. Helping patients feel listened to may encourage a more positive approach to psychological support.

Chronic postsurgical pain in the ICD-11: implications for anaesthesiology and pain medicine

Chronic postsurgical pain (CPSP) is associated with reduced health-related quality of life and disability. In some patients, it can result in long-term opioid use even after minor surgery. Epidemiological studies have reported highly varying rates of CPSP, largely because researchers have used different definitions with self-defined cut-offs for pain scores. With the introduction of the 11th revision of the World Health Organisation International Classification of Diseases and Related Health Problems (ICD-11), chronic pain is now recognised as an entity of its own, its biopsychosocial nature is emphasised, and its definition is standardised. Compared with the ICD-11 definition, the prevalence of CPSP might have been overestimated in previous studies. The ICD-11 provides a multifactorial assessment of pain severity, referring to pain intensity, pain-related interference, and pain-related distress, which cover the biopsychosocial aspects of chronic pain. These three scores can be added as extension codes to any pain diagnosis. Harmonisation of the CPSP criteria within the different coding levels of the ICD-11 might improve discrimination of CPSP from other chronic pain conditions not induced by surgery. Although neuropathic CPSP increases pain severity and requires alternative therapeutic approaches to nociceptive pain, a specific code to differentiate between neuropathic and non-neuropathic CPSP is not available. For clinical practice and research, the evidence-based ICD-11 definition, which provides clear-cut diagnostic criteria, should generally be used instead of pain scores alone. This will improve the comparability of data, form the basis for future diagnostic and therapeutic approaches, and facilitate communication.

Preoperative psychological distress and acute postoperative pain among abdominal surgery patients

OBJECTIVE

To analyze preoperative psychological distress symptoms and their association with acute postoperative pain in patients undergoing abdominal surgery.

METHOD

Prospective observational study conducted at a University Hospital in Minas Gerais, Brazil. The sample included 118 patients in the hospital's elective abdominal surgery program. Psychological distress symptoms were assessed using the Hospital Anxiety and Depression Scale (HADS). Pain levels were measured using the numeric verbal scale (NVS, 0-10 points) from admission to discharge from the post-anesthesia care unit. Descriptive statistics and an ordinal regression model were utilized to detect related factors, with a threshold for significance established at p < 0.05. Pain levels at discharge from the post-anesthesia care unit was considered the outcome variable.

FINDINGS

Preoperatively, 50.8 % exhibited symptoms of anxiety (HADS-A ≥ 8) and 16.1 % exhibited symptoms of depression (HADS-D ≥ 8), with 14.4 % presenting both symptoms. The prevalence of pain (NVS >0) in the post-anesthesia care unit was 40.3 %. At admission, 5.8 % of patients reported moderate to severe pain (NVS ≥ 4), increasing to 29.7 % at 60 min and 22.1 % at discharge. Regression analysis showed that anxiety or depression (OR = 4.49, p < 0.01) significantly increased the likelihood of experiencing higher pain levels, which was even greater when both symptoms coexisted (OR = 10.19, p < 0.01). Additionally, older age (OR = 0.94, p < 0.01) and inadequate pain management (OR = 7.67, p < 0.01) were significant predictors of pain levels at discharge.

CONCLUSION

Preoperative psychological distress, particularly the simultaneous presence of anxiety and depressive symptoms, significantly elevates the likelihood of heightened pain intensity in patients undergoing abdominal surgery.

Development and internal validation of a clinical risk tool to predict chronic postsurgical pain in adults: a prospective multicentre cohort study

ABSTRACT

Chronic postsurgical pain (CPSP) is a highly prevalent condition. To improve CPSP management, we aimed to develop and internally validate generalizable point-of-care risk tools for preoperative and postoperative prediction of CPSP 3 months after surgery. A multicentre, prospective, cohort study in adult patients undergoing elective surgery was conducted between May 2021 and May 2023. Prediction models were developed for the primary outcome according to the International Association for the Study of Pain criteria and a secondary threshold-based CPSP outcome. Models were developed with multivariable logistic regression and backward stepwise selection. Internal validation was conducted using bootstrap resampling, and optimism was corrected by shrinkage of predictor weights. Model performance was assessed by discrimination and calibration. Clinical utility was assessed by decision curve analysis. The final cohort included 960 patients, 16.3% experienced CPSP according to the primary outcome and 33.6% according to the secondary outcome. The primary CPSP model included age and presence of other preoperative pain. Predictors in the threshold-based models associated with an increased risk of CPSP included younger age, female sex, preoperative pain in the surgical area, other preoperative pain, orthopedic surgery, minimally invasive surgery, expected surgery duration, and acute postsurgical pain intensity. Optimism-corrected area-under-the-receiver-operating curves for preoperative and postoperative threshold-based models were 0.748 and 0.747, respectively. These models demonstrated good calibration and clinical utility. The primary CPSP model demonstrated fair predictive performance including 2 significant predictors. Derivation of a generalizable risk tool with point-of-care predictors was possible for the threshold-based CPSP models but requires independent validation.

N-Methyl-D-aspartate receptor antagonists for the prevention of chronic postsurgical pain: a narrative review

The N-methyl-D-aspartate receptor (NMDAR) has been linked to the development of chronic postsurgical pain (CPSP), defined as pain after surgery that does not resolve by 3 months. Once the combination of a painful stimulus and glutamate binding activates the NMDAR, calcium influx triggers signaling cascades that lead to processes like central sensitization and CPSP. Three of the most widely studied perioperative NMDAR antagonists include ketamine, magnesium, and methadone, with ketamine having garnered the greatest amount of attention. While multiple studies have found improved analgesia in the acute postoperative period, fewer studies have focused on long-term outcomes and those that have are often underpowered for CPSP or have not included those patients at highest risk. Existing meta-analyses of ketamine for CPSP are inconsistent in their findings, and studies of magnesium and methadone are even more limited. Overall, the evidence supporting NMDAR antagonists for CPSP is weak and we recommend that future studies focus on high-risk patients and potentially include combinations of NMDAR antagonists administered together for the longest duration feasible. The results of ongoing trials could have a major influence on the overall direction of the evidence supporting NMDAR antagonists in preventing CPSP.

Risk factors for persistent postoperative opioid use: an entity distinct from chronic postsurgical pain

Despite a decline in opioid prescriptions over the past decade, patients commonly receive opioid analgesics as a treatment for postoperative pain in the USA. One complication that patients may experience after surgery is persistent postoperative opioid use (PPOU), or opioid use beyond the typical recovery period. Often defined as beyond 3 months postsurgery, PPOU is frequently conflated with chronic postsurgical pain (CPSP), where pain persists well after the expected healing time following surgery. This narrative review explores the distinct risk factors for each condition, their interrelation, and potential future research directions.For PPOU, major risk factors include the risky use of substances including misuse and use disorders; depression and other mental health disorders; a history of chronic pain before surgery including back pain; and certain surgical types (ie, total knee arthropathy, open cholecystectomy, total hip arthropathy). Conversely, CPSP risk factors include the type of surgery (ie, thoracic and breast surgeries), mental health conditions (particularly catastrophizing), and pain in both the preoperative and postoperative phases. Despite the overlap of some factors, studies typically employ different frameworks when examining PPOU and CPSP, with a biopsychosocial model applied for CPSP and little emphasis on an individual's social environment employed for PPOU. Additionally, existing studies predominantly rely on retrospective insurance claims data, which may not capture the full scope of risk factors.To fill gaps in understanding, investigations may prospectively assess and analyze patient-reported outcomes, implement similar frameworks, and concurrently measure both conditions to advance the scientific understanding of PPOU and CPSP.

Mental and Physical Well-Being of Partners of People Living with Chronic Pain: A Narrative Review

This narrative review aims to explore the mental and physical well-being of partners of individuals living with chronic pain. Chronic pain not only affects those who suffer from it, but also significantly impacts the lives of their partners; however, the impacts on partners are not well recognised, despite extensive evidence indicating that their quality of life can be equally affected. This review synthesises current literature to identify the psychological and physical challenges faced by these partners, including increased stress, anxiety, depression, and the potential for developing chronic health conditions themselves. A search of Medline for "chronic pain" and "partner/spouse" from January 1990 to the present was performed, and relevant articles were selected for review. The main findings were that while partners often experience a range of negative physical and psychosocial impacts on their quality of life, dyadic coping strategies can mitigate these effects. This review underscores the importance of future research to develop targeted interventions that address the unique needs of this population, promoting better health outcomes and fostering resilience in the face of chronic pain.

Knowledge translation initiatives at the Transitional Pain Service: insights from healthcare provider outreach and patient education

Evidence-based treatment of chronic pain requires a multidisciplinary approach grounded in the biopsychosocial model. Implementing this approach within health systems relies on its acceptance by both healthcare providers and patients. While pioneering multidisciplinary pain clinics can serve as a model for implementation, a systematic effort is needed to share knowledge effectively and broadly. In the current paper we provide an overview of the knowledge translation initiatives undertaken at our Transitional Pain Service (TPS) at Toronto General Hospital, a state-of-the-art multidisciplinary pain program established in 2014 for patients at risk of developing chronic pain after surgery. The TPS team strives to enhance acceptance of this model of care among patients and providers, facilitate the establishment of similar clinics, and promote patient understanding of the integrated multidisciplinary pain care approach. Guided by the Knowledge to Action (KTA) framework, knowledge translation activities undertaken by our TPS team include clinician training, resources and outreach activities for providers, and patient education. Resource development was preceded by consultation and needs assessment among patients and providers and feedback from both groups was incorporated as part of the development process. The tailored resources were disseminated via the TPS clinic website and monitoring of online usage enables continuous evaluation of engagement. Barriers to engagement with the resources were examined through patient surveys and staff interviews. Based on these activities, we offer insights gained by our team throughout the knowledge translation process and provide recommendations for other clinical teams who wish to undertake similar initiatives.

Classification of kinesiophobia in patients after cardiac surgery under extracorporeal circulation in China: latent profile and influencing factors analysis from a cross-sectional study

OBJECTIVE

To investigate the potential classification of kinesiophobia in patients after cardiac surgery under extracorporeal circulation from a psychosocial perspective, and analyse the characteristic differences among different latent levels of patients.

STUDY DESIGN

This is a cross-sectional study of Chinese adults after cardiac surgery under extracorporeal circulation, aged 18 years and older, recruited from a tertiary hospital in North China.

METHODS

This study uses latent profile analysis to identify potential classifications of kinesiophobia in questionnaires from 348 patients undergoing cardiac surgery under extracorporeal circulation. Multiple logistic regression analysis was used to evaluate the influencing factors at different latent classifications.

RESULTS

The average performance of each indicator in Model 3 is best suited for analysis, Entropy=0.873 and bootstrap likelihood ratio test (p)＜0.0001. The result of regression equation shows postoperative time (p<0.001), age, self-efficacy, pain and social support level (p<0.05) were the factors influencing the potential profile classification of patients after cardiac surgery under extracorporeal circulation.

CONCLUSION

The study identified three distinct classifications of patients: the low kinesiophobia group, the moderate kinesiophobia-high-risk perceived symptoms group and the high kinesiophobia-high exercise avoidance group (HK-HEAG). Addressing kinesiophobia, especially in older male patients during the early postoperative period, is crucial. Enhancing self-efficacy seems effective in reducing kinesiophobia, while increasing social support may not be as beneficial for the HK-HEAG. These findings provide a basis for implementing preventive interventions in cardiac rehabilitation.

TRIAL REGISTRATION NUMBER

The research is registered with the Chinese Clinical Trial Registry (ChiCTR2200057895).

Presurgical anxiety and acute postsurgical pain predict worse chronic pain profiles after total knee/hip arthroplasty

INTRODUCTION

Total joint arthroplasties generally achieve good outcomes, but chronic pain and disability are a significant burden after these interventions. Acknowledging relevant risk factors can inform preventive strategies. This study aimed to identify chronic pain profiles 6 months after arthroplasty using the ICD-11 (International Classification of Diseases) classification and to find pre and postsurgical predictors of these profiles.

MATERIALS AND METHODS

Patients undergoing total knee/hip arthroplasty (n = 209, female = 54.5%) were assessed before surgery, 48 h and 6 months postsurgery for sociodemographic, pain-related, disability and psychological characteristics. K-means-constrained cluster analysis identified chronic pain profiles based on 6-month pain intensity, pain interference and disability. Chi-square tests or one-way ANOVA explored between-cluster differences. Multinomial regression identified predictors of cluster membership. Separate models analyzed presurgical (model 1), postsurgical (model 2) and a combination of previously significant pre and postsurgical (model 3) variables.

RESULTS

A three-cluster solution was selected, translating increasingly worse chronic pain severity: cluster 1 (C1, n = 129), cluster 2 (C2, n = 60) and cluster 3 (C3, n = 20). There were presurgical differences among clusters in the presence of other painful sites (p = 0.013, ϕc = 0.20), pain interference (p = 0.038, η2 = 0.031), disability (p = 0.020, η2 = 0.037), pain catastrophizing (p = 0.019, η2 = 0.060), anxiety (p < 0.001, η2 = 0.087), depression (p = 0.017; η2 = 0.039), self-efficacy (p = 0.018, η2 = 0.038) and satisfaction with life (p = 0.034, η2 = 0.032), postsurgical pain frequency (p = 0.003, ϕc = 0.243) and intensity (p < 0.001, η2 = 0.101). In model 1, disability predicted C2 (OR = 1.040) and anxiety predicted C3 (OR = 1.154) membership. In model 2, pain intensity predicted C3 (OR = 1.690) membership. In model 3, presurgical anxiety predicted C3 (OR = 1.181) and postsurgical pain intensity predicted C2 (OR = 1.234) and C3 (OR = 1.679) membership.

CONCLUSIONS

Most patients had low chronic pain severity at 6 months, but a relevant percentage exhibited poor outcomes. Membership to different outcome profiles was predicted by presurgical anxiety and acute postsurgical pain. These seem promising targets to prevent pain chronification that should be optimized for better surgical outcomes.

Preoperative susceptibility to developing secondary hyperalgesia is associated with post-thoracotomy pain at 2 months

BACKGROUND

Identifying the subset of patients at risk for developing persistent pain after surgery is clinically important as they could benefit from targeted prevention measures. In this prospective study, we investigated if the preoperative assessment of the individual susceptibility to developing experimentally induced secondary hyperalgesia is associated with post-thoracotomy pain at 2 months.

METHODS

Forty-one patients scheduled to undergo a posterolateral thoracotomy were recruited before surgery and followed prospectively for 2 months. The day before surgery, we experimentally induced secondary hyperalgesia at one of the two forearms and measured the change of perception to mechanical pinprick stimuli and the area of hyperalgesia. On postoperative Day 4, Day 15 and at the 2-month follow-up, patients were asked about their pain intensity at rest and during coughing and the area of secondary hyperalgesia around the scar as well as the change in perception to mechanical pinprick stimuli was measured.

RESULTS

Of the 41 patients that were recruited only 20 could be analysed. Forty per cent reported pain at the 2-month follow-up. All of them reported cough-evoked pain and 10 per cent also reported pain at rest. A binary logistic regression model with both the magnitude and extent of experimentally induced secondary hyperalgesia was statistically significant (chi-squared = 12.439, p = 0.002, McFadden R2 = 0.462) and showed excellent discriminative power (AUC = 0.938) for the presence or absence of cough-evoked pain at the 2 month follow-up.

CONCLUSION

Our findings indicate that the individual susceptibility to developing experimentally induced secondary hyperalgesia preoperatively may identify patients who are potentially vulnerable to develop persistent post-thoracotomy pain.

SIGNIFICANCE

Our data suggests that preoperatively assessed experimentally induced secondary hyperalgesia displays excellent discriminative power for the presence or absence of cough-evoked pain 2 months after thoracotomy.

Prevalence, pain trajectories, and presurgical predictors for chronic postsurgical pain in a pediatric sample in Spain with a 24-month follow-up

ABSTRACT

Pediatric chronic pain, particularly chronic postsurgical pain (CPSP), poses a significant public health challenge, impacting 20% of pediatric populations. While several presurgical predictors have been identified, there is a scarcity of data on long-term outcomes, especially beyond 1 to 2 years postsurgery. Previous research primarily focuses on North American children, creating gaps in understanding CPSP outcomes in diverse health systems, such as in Spain. This study, registered as NCT04735211, investigates CPSP in 159 children and adolescents (mean age = 12.4 years, 37.1% girls, retention rate = 65%) undergoing various surgeries in Spain. The objectives include examining CPSP prevalence (Numerical Rating Scale ≥ 4) at 3, 6, 12, and 24 months, exploring postsurgical pain trajectories through group-based trajectory modeling, and identifying potential presurgical predictors for CPSP (pain intensity, pain catastrophizing, pain anxiety, fear of pain, kinesiophobia, health-related quality of life, pain interference, and physical activity), using multiple logistic regressions. Results show a CPSP prevalence of 41% at 3 months, decreasing to 14% at 24 months. Presurgical factors including pain intensity (adjusted odds ratio [aOR] = 1.25, 95% confidence interval [CI] = 1.02-1.53), pain catastrophizing (aOR = 1.06, 95% CI = 1.00-1.13), and pain anxiety (aOR = 1.06, 95% CI = 1.02-1.11) were associated with CPSP at 3 months. Group-based trajectory modeling revealed 3 postsurgical pain trajectories: Low Pain with Rapid Recovery Group (30.2%), Moderate Pain with Recovery Group (53.5%), and High Pain with Slow Recovery Group (16.3%), with group differences in presurgical predictors, excluding physical activity. This study contributes valuable insights into CPSP, emphasizing the need for long-term follow-up. The findings could inform the implementation of preventive programs for CPSP into diverse health systems.

Pain Experiences and Coping Methods of Living Liver Donors Experiencing Chronic Pain After Surgery: Qualitative Study

BACKGROUND

Living liver donors are known to experience many physical symptoms such as pain in the postoperative period.

AIM

This qualitative study was conducted to examine pain experiences and coping methods of living liver donors experiencing postoperative chronic pain.

METHODS

The study sample consisted of 16 living liver donors. Data were collected using a personal information form and a semi-structured questionnaire. Quantitative data were analyzed as number, mean, standard deviation, and percentage. Qualitative data were analyzed within the framework of thematic and content analysis methods.

RESULTS

The mean postoperative chronic pain rate of living liver donors was 4.5. Eight of these people reported experiencing sudden, pinprick-like pain after liver transplantation. Living liver donors stated that the greatest factor that increased their pain was exertion/spontaneous movement. Half of them stated that the pain they experienced after transplantation had no impact on their daily life activities. Most of the living liver donors stated that the pain they experienced had no impact on their social lives; however, it caused sadness and psychological deterioration. The most preferred method to cope with pain was the use of medication.

CONCLUSIONS

Living liver donors experienced moderate postoperative chronic pain, and a significant proportion of them reported psychological symptoms related to the pain they experienced. A multidisciplinary pain team can help with pain management by providing training conducted in transplant centers.

Unraveling the impact of kinesiophobia on proprioception and balance: Mediation by pain, mobility, and psychological wellbeing in post-total hip replacement recovery

This study aimed to investigate the relationships between kinesiophobia, proprioception, and limits of stability in elderly individuals post-THR. Specifically, it sought to assess the direct and indirect effects of kinesiophobia on proprioception through mediating factors such as pain intensity, functional mobility, and psychological well-being. A cross-sectional observational study was conducted with 100 participants (50 post-THR patients and 50 asymptomatic elderly controls) at King Khalid University Hospital. Kinesiophobia was measured using the Tampa Scale for Kinesiophobia (TSK), proprioception was assessed via a digital inclinometer, and limits of stability were evaluated using computerized dynamic posturography. Post-THR patients exhibited significantly higher levels of kinesiophobia (p < 0.001) and impaired proprioception (p < 0.001) compared to controls. Mediation analyses revealed that pain intensity, functional mobility, and psychological well-being partially mediated the relationship between kinesiophobia and proprioception. The Sobel tests confirmed significant mediation effects for pain intensity (Z = 3.88, p = 0.021), functional mobility (Z = 2.96, p = 0.013), and psychological well-being (Z = 2.84, p = 0.015). Kinesiophobia significantly impairs proprioception and balance in elderly individuals post-THR, with these effects being partially mediated by pain intensity, functional mobility, and psychological well-being. These findings highlight the importance of addressing psychological factors in rehabilitation programs to enhance proprioceptive function and improve postural stability, thereby optimizing recovery outcomes in the post-THR population.

The Impact of Diagnosed Chronic Sleep Disorders on Outcomes Following Total Knee Arthroplasty

BACKGROUND

Up to 20% of patients undergoing total knee arthroplasty (TKA) remain dissatisfied with their outcome, leading to the identification of risk factors for poor outcomes. The purpose of this study was to analyze the effect of chronic sleep disorders on patient-reported outcomes after primary TKA.

METHODS

A retrospective review of patients undergoing primary TKA was conducted using a prospectively collected database of patients from a single institution between 2018 and 2022. The cohort was split based on the presence of documented chronic sleep disorders, identified preoperatively from the electronic medical record using current procedural terminology codes. The sample was further restricted to include all patients who have sleep disorders (SDs), as well as a 3:1 propensity-matched (on age, sex, body mass index, and American Society of Anesthesiologists class) cohort of patients who had no documented SDs (NSDs) prior to surgery. The final sample included 172 patients (SD: 43; NSD: 129). Repeated-measures linear mixed model analysis was used to analyze the progression of Knee Injury and Osteoarthritis Outcome Score (KOOS) through time between groups.

RESULTS

Those who had SDs had a lower preoperative mean total KOOS score (40.2) than the NSD group (44.1); however, this was not significantly different (P = .108). At 1 year postoperatively, those who had an SD had a significantly higher mean total KOOS score (87.2) than the NSD group (80.4), P = .005. When comparing total KOOS scores by group, over each time period, the SD group showed a better progression when compared to the NSD group, P = .001.

CONCLUSIONS

Compared to patients who did not have documented chronic sleep disorders, patients who had a prior history of chronic sleep disorders reported significantly greater improvements in most KOOS domains in the 12-month period following TKA.

Chronic Postsurgical Pain

Chronic pain is a devastating condition that impacts more than 50 million adults nationwide. It can lead to chronic opioid addiction, reduced quality of life, economic collapse, divorce, homelessness, and suicide. Chronic pain associated with surgical interventions is a common, but often misunderstood and misdiagnosed condition. Understanding chronic pain and the physical, psychological, and psychosocial links to chronic postsurgical pain can help nurses identify, prevent, or better treat the condition.

The Italian version of the Surgical Fear Questionnaire: validation of its measurement properties

BACKGROUND

Surgical fear is present in many patients awaiting surgery. However, a validated Italian version of the Surgical Fear Questionnaire (SFQ) was not available yet. Therefore, the aim of this study was to translate the SFQ into Italian and to test its reliability and validity.

METHODS

Design: prospective cohort study on Italian-speaking Swiss patients scheduled for a minimally invasive spinal procedure or spinal surgery. After forward and back translation and a pilot test, reliability and validity of the 8-item SFQ was assessed using the intraclass correlation coefficient, (ICC), Cronbach's alpha, confirmatory factor analysis (CFA), and Spearman's correlation coefficient.

RESULTS

Results on 63 patients revealed median SFQ-total scores of 22 (minimum-maximum: 0-68) at inclusion and 22.5 (0-70) one week before surgery. Test-retest reliability between first and second SFQ-total score was high, ICC=0.947 (95% CI: 0.912-0.968). Internal consistency of the SFQ-total score at both assessment times were high, Cronbach's alphas 0.916 and 0.931 respectively. This was also the case for the subscale short-term fear, item 1-4 and long-term fear, item 5-8 (range 0.853-0.909). CFA-results for a one-factor and a two-factor model favored the two-factor model. Correlations with pain catastrophizing, other anxiety measures, and health status were weak and only state anxiety assessed by PROMIS reached statistical significance.

CONCLUSIONS

We conclude that the Italian version of the SFQ is suitable for use in practice and has a high reliability. Validity and sensitivity need additional testing on a larger population.

Pain chronification risk assessment: advanced phenotyping and scoring for prediction and treatments tailored to individualized patient profile

Acute pain is a physiologic, protective life-important warning neurological signal indicating multi-level tissue modulations caused by a broad spectrum of health adverse events such as stress overload, mechanical trauma, ischemia-reperfusion, sterile and infection-triggered inflammation, single- and multi-organ damage, acute and chronic wounds, tissue remodeling and degeneration, amongst others. On the other hand, pain chronification results in a pathologic transformation from the protective pain signaling into persistent debilitative medical condition with severe consequences including but not restricted to phenotype-specific behavioral patterns, reduced quality of life, and cognitive and mood disorders. Who is predisposed to an increased vs. decreased pain sensitivity and to the pain chronification? The motivation of personalized medicine that "same size does not fit all" is getting obvious also for an advanced approach in algesiology. Consequently, an in-depth patient stratification is essential for the paradigm change in overall pain management from currently applied reactive medical services to the cost-effective predictive, preventive, and personalized medicine (PPPM/3PM) in primary (reversible damage to health and targeted protection against health-to-disease transition) and secondary (personalized protection against disease progression) care. To this end, specifically innovative concepts of phenotyping elaborated in this study play a crucial role in patient stratification for predicting pain-associated outcomes, evidence-based targeted prevention of the pain chronification, and creation of treatment algorithms tailored to individualized patient profiles.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-024-00383-3.

The effect of preoperative education on postoperative pain and function after orthopedic surgery: A systematic review and meta-analysis

OBJECTIVES

To systematically review the effect of preoperative education on reducing postoperative pain and disability in the short-term and long-term for patients undergoing orthopedic surgery.

METHODS

Pertinent randomized controlled trials were retrieved from PubMed, Cochrane Central, Embase, Medline, Scopus and CINAHL from their inception until September 10, 2023. Two authors independently conducted study selection, data extraction, and methodological quality assessment. This review was registered in PROSPERO (CRD42023470282).

RESULTS

A total of 37 RCTs were included with 27 of them being pooled for meta-analysis. Low certainty of evidence indicated that there was a small effect of preoperative education (standardized mean difference = - 0.23, 95 % CI = [- 0.39, - 0.07], p = 0.004) or combined preoperative intervention (standardized mean difference = - 0.25, 95 % CI = [- 0.41, - 0.09], p = 0.003) on postoperative pain relief.

CONCLUSIONS

Preoperative education and combined preoperative intervention only had a short-term effect on postoperative pain relief, while they were not superior to usual care in postoperative functional recovery, either short-term or long-term.

PRACTICE IMPLICATIONS

Both preoperative education and combined preoperative intervention are effective in pain control around a week postoperatively. However, optimal contents, durations, and dose of education warrant further investigation.

Much more than a biological phenomenon: A qualitative study of women's experiences of brain fog across their reproductive journey

Whilst 'brain fog' is mostly considered a biological problem little is understood about an individual's experience. This qualitative study explored women's experiences of brain fog focusing on those at the start (aged 18-25; n = 10) and end (aged 45-60; n = 10) of their reproductive journey. Descriptive thematic analysis described three themes: (i) 'daily disruptions' describing cognitive dysfunctions and the main triggers; (ii) 'the cycle of impact' with a focus on women's emotional experiences and how these can exacerbate brain fog; (iii) 'taking control' highlighting the use of self-care, physical prompts and Hormonal Replacement Therapy (HRT) to manage brain fog. Transcending these themes was the notion of 'crisis of identity' illustrating the negative impact of brain fog on the women's sense of self with some older women describing acceptance and finding it less challenging. Brain fog is much more than a biological phenomenon and has broader implications for a woman's sense of self.

Preoperative pain sensitivity and its correlation with postoperative acute and chronic pain: a systematic review and meta-analysis

BACKGROUND

Preoperative pain sensitivity (PPS) can be associated with postsurgical pain. However, estimates of this association are scarce. Confirming this correlation is essential to identifying patients at high risk for severe postoperative pain and for developing analgesic strategy. This systematic review and meta-analysis summarises PPS and assessed its correlation with postoperative pain.

METHODS

PubMed, Scopus, Cochrane Library, and PsycINFO were searched up to October 1, 2023, for studies reporting the association between PPS and postsurgical pain. Two authors abstracted estimates of the effect of each method independently. A random-effects model was used to combine data. Subgroup analyses were performed to investigate the effect of pain types and surgical procedures on outcomes.

RESULTS

A total of 70 prospective observational studies were included. A meta-analysis of 50 studies was performed. Postoperative pain was negatively associated with pressure pain threshold (PPT; r=-0.15, 95% confidence interval [CI] -0.23 to -0.07]) and electrical pain threshold (EPT; r=-0.28, 95% CI -0.42 to -0.14), but positively correlated with temporal summation of pain (TSP; r=0.21, 95% CI 0.12-0.30) and Pain Sensitivity Questionnaire (PSQ; r=0.25, 95% CI 0.13-0.37). Subgroup analysis showed that only TSP was associated with acute and chronic postoperative pain, whereas PPT, EPT, and PSQ were only associated with acute pain. A multilevel (three-level) meta-analysis showed that PSQ was not associated with postoperative pain.

CONCLUSIONS

Lower PPT and EPT, and higher TSP are associated with acute postoperative pain while only TSP is associated with chronic postoperative pain. Patients with abnormal preoperative pain sensitivity should be identified by clinicians to adopt early interventions for effective analgesia.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42023465727).

Integrating mechanistic-based and classification-based concepts into perioperative pain management: an educational guide for acute pain physicians

Chronic pain begins with acute pain. Physicians tend to classify pain by duration (acute vs chronic) and mechanism (nociceptive, neuropathic and nociplastic). Although this taxonomy may facilitate diagnosis and documentation, such categories are to some degree arbitrary constructs, with significant overlap in terms of mechanisms and treatments. In clinical practice, there are myriad different definitions for chronic pain and a substantial portion of chronic pain involves mixed phenotypes. Classification of pain based on acuity and mechanisms informs management at all levels and constitutes a critical part of guidelines and treatment for chronic pain care. Yet specialty care is often siloed, with advances in understanding lagging years behind in some areas in which these developments should be at the forefront of clinical practice. For example, in perioperative pain management, enhanced recovery protocols are not standardized and tend to drive treatment without consideration of mechanisms, which in many cases may be incongruent with personalized medicine and mechanism-based treatment. In this educational document, we discuss mechanisms and classification of pain as it pertains to commonly performed surgical procedures. Our goal is to provide a clinical reference for the acute pain physician to facilitate pain management decision-making (both diagnosis and therapy) in the perioperative period.

Incidence and Risk Factors of Chronic Postoperative Pain in Same-day Surgery: A Prospective Cohort Study

BACKGROUND

The amount of same-day surgery has increased markedly worldwide in recent decades, but there remains limited evidence on chronic postsurgical pain in this setting.

METHODS

This study assessed pain 90 days after ambulatory surgery in an international, multicenter prospective cohort study of patients at least 45 yr old with comorbidities or at least 65 yr old. Pain was assessed using the Brief Pain Inventory. Chronic postsurgical pain was defined as a change of more than 1 point in self-rated average pain at the surgical site between baseline and 90 days, and moderate to severe chronic postsurgical pain was defined as a score greater than 4 in self-rated average pain at the surgical site at 90 days. Risk factors for chronic postsurgical pain were identified using multivariable logistic regression.

RESULTS

Between November 2021 and January 2023, a total of 2,054 participants were included, and chronic postsurgical pain occurred in 12% of participants, of whom 93.1% had new chronic pain at the surgical site (i.e., participants without pain before surgery). Moderate to severe chronic postsurgical pain occurred in 9% of overall participants. Factors associated with chronic postsurgical pain were active smoking (odds ratio, 1.82; 95% CI, 1.20 to 2.76), orthopedic surgery (odds ratio, 4.7; 95% CI, 2.24 to 9.7), plastic surgery (odds ratio, 4.3; 95% CI, 1.97 to 9.2), breast surgery (odds ratio, 2.74; 95% CI, 1.29 to 5.8), vascular surgery (odds ratio, 2.71; 95% CI, 1.09 to 6.7), and ethnicity (i.e., for Hispanic/Latino ethnicity, odds ratio, 3.41; 95% CI, 1.68 to 6.9 and for First Nations/native persons, odds ratio, 4.0; 95% CI, 1.05 to 15.4).

CONCLUSIONS

Persistent postsurgical pain after same-day surgery is common, is usually moderate to severe in nature, and occurs mostly in patients without chronic pain before surgery.

EDITOR’S PERSPECTIVE

Identification of Presurgical Risk Factors for the Development of Chronic Postsurgical Pain in Adults: A Comprehensive Umbrella Review

Purpose

Risk factors for the development of chronic postsurgical pain (CPSP) have been reported in primary studies and an increasing number of reviews. The objective of this umbrella review was to compile and understand the published presurgical risk factors associated with the development of CPSP for various surgery types.

Methods

Six databases were searched from January 2000 to June 2023 to identify meta-analyses, scoping studies, and systematic reviews investigating presurgical CPSP predictors in adult patients. Articles were screened by title/abstract and subsequently by full text by two independent reviewers. The selected papers were appraised for their scientific quality and validity. Data were extracted and descriptively analyzed.

Results

Of the 2344 retrieved articles, 36 reviews were selected for in-depth scrutiny. The number of primary studies in these reviews ranged from 4 to 317. The surgery types assessed were arthroplasty (n = 13), spine surgery (n = 8), breast surgery (n = 4), shoulder surgery (n = 2), thoracic surgery (n = 2), and carpal tunnel syndrome (n = 1). One review included a range of orthopedic surgeries; six reviews included a variety of surgeries. A total of 39 presurgical risk factors were identified, some of which shared the same defining tool. Risk factors were themed into six broad categories: psychological, pain-related, health-related, social/lifestyle-related, demographic, and genetic. The strength of evidence for risk factors was inconsistent across different reviews and, in some cases, conflicting. A consistently high level of evidence was found for preoperative pain, depression, anxiety, and pain catastrophizing.

Conclusion

This umbrella review identified a large number of presurgical risk factors which have been suggested to be associated with the development of CPSP after various surgeries. The identification of presurgical risk factors is crucial for the development of screening tools to predict CPSP. Our findings will aid in designing screening tools to better identify patients at risk of developing CPSP and inform strategies for prevention and treatment.

Avoidance and Endurance Responses to Pain Before and with Advanced Chronification: Preliminary Results from a Questionnaire Survey in Adult Patients with Non-Cancer Pain Conditions

Purpose

The Avoidance-Endurance Model postulates fear-avoidance responses and endurance responses as important psychological mechanisms in the development and maintenance of chronic pain. The present study aims to investigate potential differences in avoidance and endurance responses to pain before and with advanced chronification.

Patients and Methods

Two samples of adults with non-cancer pain at two different stages of chronicity were compared: One with pain and risk factors for chronicity (n=26, part of the PAIN2020 project) and one with chronic pain (n=33 from a pain day care clinic). The German Pain Questionnaire, the Graded Chronic Pain Scale (GCPS) and medical reports were used to measure duration and severity of pain. Responses to pain were assessed with the Avoidance-Endurance Questionnaire (AEQ) and psychological strain with the Depression, Anxiety and Stress Scales (DASS).

Results

Both groups were primarily affected by musculoskeletal pain. Although not yet chronified, the risk group reported comparable GCPS levels of pain intensity and disability. Depression and stress ratings were also similar, except for anxiety, which was significantly elevated in the chronic pain sample (p<.001). The AEQ scales did not differ between groups, neither on any of the fear-avoidance- nor endurance-related dimensions. A post-hoc regression analysis revealed a significant prediction of fear-avoidance by pain-related disability (p<.001). The regression model for endurance responses was not significant.

Conclusion

Patients with risk factors of chronification experience substantial pain-related burden. Responses to pain in the realm of the Avoidance-Endurance model do not appear to vary as a function of chronification. While fear-avoidance and pain-related disability correlate positively, endurance could not be associated to any of our variables.

Mechanisms and Preventative Strategies for Persistent Pain following Knee and Hip Joint Replacement Surgery: A Narrative Review

Chronic postsurgical pain (CPSP) following total knee arthroplasty (TKA) and total hip arthroplasty (THA) is a prevalent complication of joint replacement surgery which has the potential to decrease patient satisfaction, increase financial burden, and lead to long-term disability. The identification of risk factors for CPSP following TKA and THA is challenging but essential for targeted preventative therapy. Recent meta-analyses and individual studies highlight associations between elevated state anxiety, depression scores, preoperative pain, diabetes, sleep disturbances, and various other factors with an increased risk of CPSP, with differences observed in prevalence between TKA and THA. While the etiology of CPSP is not fully understood, several factors such as chronic inflammation and preoperative central sensitization have been identified. Other potential mechanisms include genetic factors (e.g., catechol-O-methyltransferase (COMT) and potassium inwardly rectifying channel subfamily J member 6 (KCNJ6) genes), lipid markers, and psychological risk factors (anxiety and depression). With regards to therapeutics and prevention, multimodal pharmacological analgesia, emphasizing nonopioid analgesics like acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs), has gained prominence over epidural analgesia. Nerve blocks and local infiltrative anesthesia have shown mixed results in preventing CPSP. Ketamine, an N-methyl-D-aspartate (NMDA)-receptor antagonist, exhibits antihyperalgesic properties, but its efficacy in reducing CPSP is inconclusive. Lidocaine, an amide-type local anesthetic, shows tentative positive effects on CPSP. Selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) have mixed results, while gabapentinoids, like gabapentin and pregabalin, present hopeful data but require further research, especially in the context of TKA and THA, to justify their use for CPSP prevention.

Night time heart rate predicts next-day pain in fibromyalgia and primary back pain

Introduction

Primary chronic pain is pain that persists for over 3 months without associated measurable tissue damage. One of the most consistent findings in primary chronic pain is its association with autonomic hyperactivation. Yet whether the autonomic hyperactivation causes the pain or results from it is still unclear. It is also unclear to what extent autonomic hyperactivation is related to experienced pain intensity in different subtypes or primary chronic pain.

Objectives

Our first aim was to test lagged relationships between the markers of autonomic activation (heart rate) and pain intensity to determine its directionality. The main question here was whether autonomic biomarkers predict pain intensity or whether pain intensity predicts autonomic biomarkers. The second aim was to test whether this relationship is different between people with primary back pain and people with fibromyalgia.

Methods

Sixty-six patients with chronic pain were observed over an average of 81 days. Sleep heart rate and heart rate variability were measured with a wearable sensor, and pain intensity was assessed from daily subjective reports.

Results

The results showed a predictive relationship between sleep heart rate and next-day pain intensity (P < 0.05), but not between daily pain intensity and next night heart rate. There was no interaction with the type of chronic pain.

Conclusions

These findings suggest that autonomic hyperactivation, whether stress-driven or arising from other causes, precedes increases in primary chronic pain. Moreover, the present results suggest that autonomic hyperactivation is a common mechanism underlying the pain experience in fibromyalgia and chronic back pain.

Association Between Pain Coping and Symptoms of Anxiety and Depression, and Work Absenteeism in People With Upper Limb Musculoskeletal Disorders: A Systematic Review and Meta-analysis

OBJECTIVE

To determine the prospective association of pain coping strategies and symptoms of anxiety and depression with work absenteeism in people with upper limb musculoskeletal disorders.

DATA SOURCES

A systematic search of PubMed, Web of Science, Embase, Cochrane Library, and Scopus databases was conducted from inception to September 23, 2022.

STUDY SELECTION

Prospective observational studies of adults with upper limb musculoskeletal disorders were included. Included studies had to provide data on the association of pain coping strategies (catastrophizing, kinesiophobia, self-efficacy or fear avoidance) or symptoms of anxiety and depression with work absenteeism.

DATA EXTRACTION

Study selection, data extraction, and assessment of methodological quality (Newcastle Ottawa Scale) were performed by 2 independent authors. Random-effects models were used for quantitative synthesis.

DATA SYNTHESIS

Eighteen studies (n=12,393 participants) were included. Most studies (77.8%) reported at least 1 significant association between 1 or more exposure factors (pain coping strategies or symptoms of anxiety and depression) and work absenteeism. Meta-analyses showed a statistically significant correlation between the exposure factors of catastrophizing (r=0.28, 95% confidence interval [CI]: 0.15 to 0.40; P<.0001) and symptoms of anxiety and depression (r=0.23, 95% CI: 0.10 to 0.34; P=.0003) with work absenteeism. The correlation between self-efficacy and work absenteeism was non-significant (r=0.24, 95% CI: -0.02 to 0.47; P=.0747).

CONCLUSIONS

Rehabilitation teams should consider assessing catastrophizing and symptoms of anxiety and depression to identify patients at risk for work absenteeism. Addressing these variables may also be considered in return-to-work programs for individuals with upper limb disorders.

Moderating effects of preoperative knee pain and pain catastrophizing on the relation between COMT rs4680 genotypes and chronic postsurgical pain in total knee arthroplasty patients

BACKGROUND

The Catechol-O-methyltransferase (COMT) gene, responsible for encoding an enzyme crucial in the metabolism of catecholamines, is known to play a significant role in pain perception. Polymorphisms within this gene, particularly the COMT rs4680 genotypes, have been linked to various acute pain phenotypes. This prospective cohort study examines interactions among the genetic polymorphism COMT rs4680 genotypes, preoperative knee pain, and pain catastrophizing in chronic postsurgical pain (CPSP) at 3, 6, and 12 months post-total knee arthroplasty (TKA).

STUDY DESIGN

A total of 280 patients undergoing primary unilateral TKA participated, sharing demographic details, preoperative knee pain levels, psychological variables (pain catastrophizing), and COMT rs4680 genotyping via venous blood samples. Telephone interviews at specified intervals enabled the application of binary logistic regressions and interaction models.

RESULTS

Significant influences of preoperative knee pain and pain catastrophizing on postsurgical outcomes were observed. Specifically, at the first time point (T1, 3 months post-TKA), a notable moderation effect was identified in preoperative knee pain (R2 change = 0.026, p = 0.026). The Johnson-Neyman regions of significance (RoS) indicated these moderation effects were significant above a threshold of 17.18 (p = 0.05), accounting for 26.4%. At the third time point (T3, 12 months post-TKA), a complex three-way interaction among genotypes (GG, GA, and AA carriers) was evident, resulting in an R2 change of 0.051 (p = 0.009). Here, the RoS for pain catastrophizing was above 32.74 for 30.5% of GG genotype carriers, above 22.38 for 50.8% of GA carriers, and below 11.94 for 63.2% of AA carriers.

CONCLUSION

This study illuminates the significant role of the COMT Val158Met rs4680 polymorphism in susceptibility to prolonged pain following TKA. It also elucidates how these genetic genotypes interplay with preoperative knee pain and pain catastrophizing. Such intricate genetic-psychological-pain relationships necessitate additional investigation to confirm these findings and potentially guide post-TKA pain management strategies.

Pain trajectories and neuropathic pain symptoms following lung cancer surgery: A prospective cohort study

BACKGROUND

Persistent postsurgical pain (PPSP) after lung cancer surgery is common and current definitions are based on evaluations at a single time point after surgery. Pain intensity and symptoms may however fluctuate and change over time, and be impacted by multiple and shifting factors. Studies of postoperative recovery patterns and transition from acute to chronic pain are needed for further investigation of preventive measures and treatments to modify unfavourable recovery paths.

METHODS

In this explorative study, 85 patients undergoing surgery due to either presumptive or confirmed lung cancer reported pain intensities bi-monthly for 12 months. Pain trajectories during recovery were investigated, using group-based trajectory modelling. Associations with possible risk factors for PPSP, including clinical variables and anxiety and depression score (HADS), were also explored.

RESULTS

A trajectory model containing three 12-month pain recovery groups was computed. One group without PPSP fully recovered (50%) within two to three months. Another group with mild-intensity PPSP followed a protracted recovery trajectory (37%), while incomplete recovery was observed in the last group (13%). Acute postoperative pain and younger age were associated with a less favourable recovery trajectory. More neuropathic pain symptoms were observed in patients with incomplete recovery.

CONCLUSIONS

Three clinically relevant recovery trajectories were identified, based on comprehensive pain tracking. Higher acute postoperative pain intensity was associated with an unfavourable pain recovery trajectory.

SIGNIFICANCE STATEMENT

Understanding the transition from acute to chronic postoperative pain and identifying preoperative risk factors is essential for the development of targeted treatments and the implementation of preventive measures. This study (1) identified distinct recovery trajectories based on frequent pain assessment follow-ups for 12 months after surgery and (2) evaluated risk factors for unfavourable postoperative pain recovery paths. Findings suggest that early higher postoperative pain intensity is associated with an unfavourable long-term recovery path.

Preoperative psychological symptoms and chronic postsurgical pain: analysis of the prospective China Surgery and Anaesthesia Cohort study

BACKGROUND

Both preoperative psychological symptoms and chronic postsurgical pain (CPSP) are prevalent conditions and major concerns among surgery patients, with inconclusive associations.

METHODS

Based on the China Surgery and Anaesthesia Cohort (CSAC), we recruited 8350 surgery patients (40-65 yr old) from two medical centres between July 2020 and March 2023. Patients with preoperative psychological symptoms (i.e. anxiety, depression, stress reaction, and poor sleep quality) were identified using corresponding well-established scales. We then examined the associations of individual preoperative psychological symptoms and major patterns of preoperative psychological symptoms (identified by k-means clustering analysis) with CPSP, and different pain trajectories within 3 months. Lastly, mediation analyses were conducted to elucidate the mediating role of surgery/anaesthesia-related factors and the presence of 1-month postoperative psychological symptoms on the studied associations.

RESULTS

We included 1302 (1302/8350, 15.6%) CPSP patients. When analysed separately, all studied preoperative psychological symptoms were associated with increased CPSP risk, with the most pronounced odds ratio noted for anxiety (1.52, 95% confidence interval [CI] 1.23-1.86). Compared with patients clustered in the minor symptom group, excess risk of CPSP and experiencing an increasing pain trajectory was increased among patients with preoperative psychological symptoms featured by sleep disturbances (odds ratio=1.46, 95% CI 1.25-1.70 for CPSP and 1.58, 95% CI 1.20-2.08 for increasing pain trajectory) and multiple psychological symptoms (1.84 [95% CI 1.48-2.28] and 4.34 [95% CI 3.20-5.88]). Mediation analyses revealed acute/subacute postsurgical pain and psychological symptoms existing 1 month after surgery as notable mediators of the observed associations.

CONCLUSIONS

The presence of preoperative psychological symptoms might individually or jointly increase the risk of chronic postsurgical pain or experiencing deterioration in pain trajectory. Interventions for managing acute/subacute postsurgical pain and psychological symptoms at 1 month after surgery might help reduce such risk.

CLINICAL TRIAL REGISTRATION

ChiCTR2000034039.

Effects of Physical Exercise and Motor Activity on Depression and Anxiety in Post-Mastectomy Pain Syndrome

BACKGROUND

Chronic post-surgical pain is a condition persisting for not less than 3 months after surgical intervention. It is evaluated that 25-60% of women who underwent breast cancer excision suffer from post-mastectomy pain syndrome, and anxiety, depression, sleep disturbance, and catastrophizing. Physical activity can reduce the risk of chronic diseases and has a good impact on mood and cognitive function. The aim of this study was to estimate the influence of physical activity on the intensity of pain, depression, and anxiety in women who underwent mastectomy for breast cancer removal.

METHODS

A prospective observational unicentric cohort study was performed. Patients were females who underwent unilateral or bilateral mastectomy. The Numerical Rating Scale (NRS) was used to measure pain intensity, Beck's Depression Inventory (BDI) for depression, and Generalized Anxiety Disorders-7 (GAD-7) for anxiety evaluation. Physical activity was assessed by the International Physical Activity Questionnaire (IPAQ). Interleukin (IL)-17, IL-1β, cortisol, adrenocorticotropic hormone (ACTH), and brain-derived neurotrophic factor (BDNF) were also evaluated in the blood of patients. All evaluations were assessed 3 and 6 months after the surgery.

RESULTS

Adequate physical activity reduced the intensity of pain, depression, and anxiety symptoms in women affected by post-mastectomy pain syndrome. Moreover, adequately active women showed a reduction in biomarkers of inflammation, cortisol, ACTH, and an increase of BDNF.

CONCLUSIONS

Our results suggest that physical activity can improve the quality of life, reduce the intensity of pain and inflammatory markers, and be useful in the reduction of associated anxiety and depression.

Expectations of treatment outcome in complex cases of patients with chronic pain: A study on the DATAPAIN cohort

BACKGROUND

A better insight in how the biopsychosocial factors influence patient outcome(s) may provide information that helps selecting the optimal pain management for a specific group.

METHODS

Categorization was made in the prospective DATAPAIN registry, in which patients with pain severity (Numeric Rating Scale [NRS]: 7-10), depression or anxiety (Hospital Anxiety and Depression Scale: > 10), and pain catastrophizing (Pain Catastrophizing Scale: > 31) were identified as complex cases. Patient outcomes; treatment satisfaction on the Patient Global Impression of Change (PGIC), pain relief (NRS), pain interference on the Brief Pain Inventory (BPI) and quality of life indicator General Perceived Health (GPH) were evaluated. Logistic regression analyzed if belonging to the complex cases showed modification in the outcome of the PGIC and GPH. Linear regression was observed if complex cases differed in average reduction in pain relief and interference compared to non-complex cases.

RESULTS

1637 patients were included, of which 345 (21.08%) were considered complex cases. The changes in scores of pain relief and BPI active subscale were not significantly different between groups. The BPI affective subscale had a different change in score (-0.509; p: 0.002). The complex cases had an odds ratio (OR) of 0.59 (95% confidence interval [CI]: 0.36-0.77) on treatment satisfaction compared to non-complex cases, and an OR of 0.28 (95% CI: 0.11-0.56) on the GPH.

CONCLUSION

When treating patients with complex cases, desired treatment outcome(s) should be recognized by specialists and patients, as these may be less likely to occur.

[Transitional pain service in surgery as an optimal strategy for the treatment and prevention of chronic postoperative pain]

The problem of chronic postoperative pain (CPP) has remained relevant over the past decades, despite the active development of anesthesiology and surgery. Existing approaches to the treatment of acute postoperative pain do not provide effective prevention of CPP. The analysis of the results of studies on this problem was carried out. It was shown that the introduction of an interdisciplinary transitional pain service in surgery allows to increase the effectiveness of prevention and treatment of CPP, accompanying patients with high risks of pain chronization at each stage of surgical treatment (surgery planning, perioperative and outpatient, after discharge up to full recovery after surgery). The interdisciplinary nature of the transitional pain service in surgery ensures the timeliness and multimodality of the pain treatment methods used. It can be concluded that the development of a transitional pain service is an optimal strategy for the prevention and treatment of CPP.

Vigilance to Painful Laser Stimuli is Associated with Increased State Anxiety and Tense Arousal

Introduction

Pain is frequently accompanied by enhanced arousal and hypervigilance to painful sensations. Here, we describe our findings in an experimental vigilance task requiring healthy participants to indicate when randomly timed moderately painful stimuli occur in a long train of mildly painful stimuli.

Methods

During a continuous performance task with painful laser stimuli (CPTpain), 18 participants rated pain intensity, unpleasantness, and salience. We tested for a vigilance decrement over time using classical metrics including correct targets (hits), incorrectly identified non-targets (false alarms), hit reaction time, and false alarm reaction time. We measured state anxiety and tense arousal before and after the task.

Results

We found a vigilance decrement across four 12.5-minute blocks of painful laser stimuli in hits [F3,51=2.91; p=0.043; time block 1>block 4 (t=2.77; p=0.035)]. Both self-report state anxiety (tpaired,17=3.34; p=0.0039) and tense arousal (tpaired,17=3.20; p=0.0053) increased after the task. We found a vigilance decrement during our laser pain vigilance task consistent with vigilance decrements found in other stimulus modalities. Furthermore, state anxiety positively correlated with tense arousal.

Discussion

CPTpain acutely increased tense arousal and state anxiety, consistent with previous results implicating the reciprocal interaction of state anxiety and acute painful sensations and the role of pain in augmenting tense arousal. These results may indicate a psychological process which predisposes the hypervigilant to developing greater acute pain, resulting in positive feedback, greater pain and anxiety.

Mechanisms inherent in acute-to-chronic pain after surgery - risk, diagnostic, predictive, and prognostic factors

PURPOSE OF REVIEW

Pain is an expected consequence of a surgery, but it is far from being well controlled. One major complication of acute pain is its risk of persistency beyond healing. This so-called chronic post-surgical pain (CPSP) is defined as new or increased pain due to surgery that lasts for at least 3 months after surgery. CPSP is frequent, underlies a complex bio-psycho-social process and constitutes an important socioeconomic challenge with significant impact on patients' quality of life. Its importance has been recognized by its inclusion in the eleventh version of the ICD (International Classification of Diseases).

RECENT FINDINGS

Evidence for most pharmacological and non-pharmacological interventions preventing CPSP is inconsistent. Identification of associated patient-related factors, such as psychosocial aspects, comorbidities, surgical factors, pain trajectories, or biomarkers may allow stratification and selection of treatment options based on underlying individual mechanisms. Consequently, the identification of patients at risk and implementation of individually tailored, preventive, multimodal treatment to reduce the risk of transition from acute to chronic pain is facilitated.

SUMMARY

This review will give an update on current knowledge on mechanism-based risk, prognostic and predictive factors for CPSP in adults, and preventive and therapeutic approaches, and how to use them for patient stratification in the future.

Brain morphology predicts individual sensitivity to pain: a multicenter machine learning approach

ABSTRACT

Sensitivity to pain shows a remarkable interindividual variance that has been reported to both forecast and accompany various clinical pain conditions. Although pain thresholds have been reported to be associated to brain morphology, it is still unclear how well these findings replicate in independent data and whether they are powerful enough to provide reliable pain sensitivity predictions on the individual level. In this study, we constructed a predictive model of pain sensitivity (as measured with pain thresholds) using structural magnetic resonance imaging-based cortical thickness data from a multicentre data set (3 centres and 131 healthy participants). Cross-validated estimates revealed a statistically significant and clinically relevant predictive performance (Pearson r = 0.36, P < 0.0002, R2 = 0.13). The predictions were found to be specific to physical pain thresholds and not biased towards potential confounding effects (eg, anxiety, stress, depression, centre effects, and pain self-evaluation). Analysis of model coefficients suggests that the most robust cortical thickness predictors of pain sensitivity are the right rostral anterior cingulate gyrus, left parahippocampal gyrus, and left temporal pole. Cortical thickness in these regions was negatively correlated to pain sensitivity. Our results can be considered as a proof-of-concept for the capacity of brain morphology to predict pain sensitivity, paving the way towards future multimodal brain-based biomarkers of pain.

Prognostic Factors for Postoperative Chronic Pain after Knee or Hip Replacement in Patients with Knee or Hip Osteoarthritis: An Umbrella Review

Knee and hip osteoarthritis are highly prevalent in the older population. Management of osteoarthritis-related pain includes conservative or surgical treatment. Although knee or hip joint replacement is associated with positive outcomes, up to 30% of patients report postoperative pain in the first two years. This study aimed to synthesize current evidence on prognostic factors for predicting postoperative pain after knee or hip replacement. An umbrella review of systematic reviews was conducted to summarize the magnitude and quality of the evidence for prognostic preoperative factors predictive of postoperative chronic pain (>6 months after surgery) in patients who had received knee or hip replacement. Searches were conducted in MEDLINE, CINAHL, PubMed, PEDro, SCOPUS, Cochrane Library, and Web of Science databases from inception up to 5 August 2022 for reviews published in the English language. A narrative synthesis, a risk of bias assessment, and an evaluation of the evidence confidence were performed. Eighteen reviews (nine on knee surgery, four on hip replacement, and seven on both hip/knee replacement) were included. From 44 potential preoperative prognostic factors, just 20 were judged as having high or moderate confidence for robust findings. Race, opioid use, preoperative function, neuropathic pain symptoms, pain catastrophizing, anxiety, other pain sites, fear of movement, social support, preoperative pain, mental health, coping strategies, central sensitization-associated symptoms, and depression had high/moderate confidence for an association with postoperative chronic pain. Some comorbidities such as heart disease, stroke, lung disease, nervous system disorders, and poor circulation had high/moderate confidence for no association with postoperative chronic pain. This review has identified multiple preoperative factors (i.e., sociodemographic, clinical, psychological, cognitive) associated with postoperative chronic pain after knee or hip replacement. These factors may be used for identifying individuals at a risk of developing postoperative chronic pain. Further research can investigate the impact of using such prognostic data on treatment decisions and patient outcomes.

Prognostic models for chronic postsurgical pain-Current developments, trends, and challenges

PURPOSE OF REVIEW

Prognostic models for chronic postsurgical pain (CPSP) aim to predict the likelihood for development and severity of CPSP in individual patients undergoing surgical procedures. Such models might provide valuable information for healthcare providers, allowing them to identify patients at higher risk and implement targeted interventions to prevent or manage CPSP effectively. This review discusses the latest developments of prognostic models for CPSP, their challenges, limitations, and future directions.

RECENT FINDINGS

Numerous studies have been conducted aiming to develop prognostic models for CPSP using various perioperative factors. These include patient-related factors like demographic variables, preexisting pain conditions, psychosocial aspects, procedure-specific characteristics, perioperative analgesic strategies, postoperative complications and, as indicated most recently, biomarkers. Model generation, however, varies and performance and accuracy differ between prognostic models for several reasons and validation of models is rather scarce.

SUMMARY

Precise methodology of prognostic model development needs advancements in the field of CPSP. Development of more accurate, validated and refined models in large-scale cohorts is needed to improve reliability and applicability in clinical practice and validation studies are necessary to further refine and improve the performance of prognostic models for CPSP.

Predicting chronic postsurgical pain: current evidence and a novel program to develop predictive biomarker signatures

ABSTRACT

Chronic pain affects more than 50 million Americans. Treatments remain inadequate, in large part, because the pathophysiological mechanisms underlying the development of chronic pain remain poorly understood. Pain biomarkers could potentially identify and measure biological pathways and phenotypical expressions that are altered by pain, provide insight into biological treatment targets, and help identify at-risk patients who might benefit from early intervention. Biomarkers are used to diagnose, track, and treat other diseases, but no validated clinical biomarkers exist yet for chronic pain. To address this problem, the National Institutes of Health Common Fund launched the Acute to Chronic Pain Signatures (A2CPS) program to evaluate candidate biomarkers, develop them into biosignatures, and discover novel biomarkers for chronification of pain after surgery. This article discusses candidate biomarkers identified by A2CPS for evaluation, including genomic, proteomic, metabolomic, lipidomic, neuroimaging, psychophysical, psychological, and behavioral measures. Acute to Chronic Pain Signatures will provide the most comprehensive investigation of biomarkers for the transition to chronic postsurgical pain undertaken to date. Data and analytic resources generatedby A2CPS will be shared with the scientific community in hopes that other investigators will extract valuable insights beyond A2CPS's initial findings. This article will review the identified biomarkers and rationale for including them, the current state of the science on biomarkers of the transition from acute to chronic pain, gaps in the literature, and how A2CPS will address these gaps.

The incidence, impact, and risk factors for moderate to severe persistent pain after breast cancer surgery: a prospective cohort study

BACKGROUND

Few Australasian studies have evaluated persistent pain after breast cancer surgery.

OBJECTIVE

To evaluate the incidence, impact, and risk factors of moderate to severe persistent pain after breast cancer surgery in a New Zealand cohort.

DESIGN

Prospective cohort study.

METHODS

Consented patients were reviewed at 3 timepoints (preoperative, 2 weeks and 6 months postoperative). Pain incidence and interference, psychological distress and upper limb disability were assessed perioperatively. Clinical, demographic, psychological, cancer treatment-related variables, quantitative sensory testing, and patient genotype (COMT, OPRM1, GCH1, ESR1, and KCNJ6) were assessed as risk factors using multiple logistic regression.

RESULTS

Of the 173 patients recruited, 140 completed the 6-month follow-up. Overall, 15.0% (n = 21, 95% CI: 9.5%-22.0%) of patients reported moderate to severe persistent pain after breast cancer surgery with 42.9% (n = 9, 95% CI: 21.9%-66.0%) reporting likely neuropathic pain. Pain interference, upper limb dysfunction and psychological distress were significantly higher in patients with moderate to severe pain (P < .004). Moderate to severe preoperative pain (OR= 3.60, 95% CI: 1.13-11.44, P = .03), COMT rs6269 GA genotype (OR = 5.03, 95% CI: 1.49-17.04, P = .009) and psychological distress at postoperative day 14 (OR= 1.08, 95% CI: 1.02-1.16, P = .02) were identified as risk factors. Total intravenous anesthesia (OR= 0.31, 95% CI: 0.10 - 0.99, P = .048) was identified as protective.

CONCLUSION

The incidence of moderate to severe persistent pain after breast cancer surgery is high with associated pain interference, physical disability, and psychological distress. Important modifiable risk factors were identified to reduce this important condition.

Chronic post-thoracotomy pain after lung cancer surgery: a prospective study of preoperative risk factors

OBJECTIVES

The objective of this longitudinal cohort study was to investigate if preoperative pain mechanisms, anxiety, and depression increase risk of developing chronic post-thoracotomy pain (CPTP) after lung cancer surgery.

METHODS

Patients with suspected or confirmed lung cancer undergoing surgery by either video-assisted thoracoscopic surgery or anterior thoracotomy were recruited consecutively. Preoperative assessments were conducted by: quantitative sensory testing (QST) (brush, pinprick, cuff pressure pain detection threshold, cuff pressure tolerance pain threshold, temporal summation and conditioned pain modulation), neuropathic pain symptom inventory (NPSI), and the Hospital Anxiety and Depression Scale (HADS). Clinical parameters in relation to surgery were also collected. Presence of CPTP was determined after six months and defined as pain of any intensity in relation to the operation area on a numeric rating scale form 0 (no pain) to 10 (worst pain imaginable).

RESULTS

A total of 121 patients (60.2 %) completed follow-up and 56 patients (46.3 %) reported CPTP. Development of CPTP was associated with higher preoperative HADS score (p=0.025), higher preoperative NPSI score (p=0.009) and acute postoperative pain (p=0.042). No differences were observed in relation to preoperative QST assessment by cuff algometry and HADS anxiety and depression sub-scores.

CONCLUSIONS

High preoperative HADS score preoperative pain, acute postoperative pain intensity, and preoperative neuropathic symptoms were was associated with CPTP after lung cancer surgery. No differences in values of preoperative QST assessments were found. Preoperative assessment and identification of patients at higher risk of postoperative pain will offer opportunity for further exploration and development of preventive measures and individualised pain management depending on patient risk profile.

Effectiveness of Acceptance and Commitment Therapy (ACT) for the Management of Postsurgical Pain: Study Protocol of a Randomized Controlled Trial (SPINE-ACT Study)

Research on the use of Acceptance and Commitment Therapy (ACT) for patients with degenerative lumbar pathology awaiting surgery are limited. However, there is evidence to suggest that this psychological therapy may be effective in improving pain interference, anxiety, depression, and quality of life. This is the protocol for a randomized controlled trial (RCT) to evaluate the effectiveness of ACT compared to treatment as usual (TAU) for people with degenerative lumbar pathology who are candidates for surgery in the short term. A total of 102 patients with degenerative lumbar spine pathology will be randomly assigned to TAU (control group) or ACT + TAU (intervention group). Participants will be assessed after treatment and at 3-, 6-, and 12-month follow-ups. The primary outcome will be the mean change from baseline on the Brief Pain Inventory (pain interference). Secondary outcomes will include changes in pain intensity, anxiety, depression, pain catastrophizing, fear of movement, quality of life, disability due to low back pain (LBP), pain acceptance, and psychological inflexibility. Linear mixed models will be used to analyze the data. Additionally, effect sizes and number needed to treat (NNT) will be calculated. We posit that ACT may be used to help patients cope with the stress and uncertainty associated with their condition and the surgery itself.

Effectiveness of Communication Strategies in the Management of Chronic Postsurgical Pain: Protocol for a Systematic Review and Meta-Analysis

Purpose

To describe the details of a systematic review to assess the current evidence about the efficacy of communication strategies on the prevention of chronic postsurgical pain (CPSP).

Methods

The protocol for this systematic review was based on the Cochrane Handbook methodology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) recommendations. A systematic search of the literature on electronic databases Medline, Embase, Cochrane Library, CINAHL, PsycINFO, and Web of Science (from the inception to 19 June 2022) was carried out using predefined search terms to identify relevant studies. This review will include randomized clinical trials or observational studies. The search strategy consisted of keywords and index terms related to "clinician", "communication" or "post-surgical pain". Inclusion criteria are as follows: randomized clinical trials or observational studies using a parallel group design that assess the efficacy of communication interventions in patients undergoing surgery and that assess pain and pain-related disability. We considered interventions that included any type of written, verbal, and non-verbal communication in combination with other interventions or without. Control groups may include no communication intervention or another intervention distinctly different. We excluded studies with follow-up duration of less than 3 months, patients aged <18 years, and studies for which no reviewer had language proficiency (eg, Chinese, Korean). Descriptive statistics will be used to summarize quantitative findings. Meta-analysis will only be considered if at least three studies used the same outcome with comparable interventions, as we expect a wide heterogeneity of study population and settings.

Conclusion

This systematic review and meta-analysis will be an important source for clinicians and researchers to understand the influence of communication to prevent CPSP.

Study Registration

This protocol is registered with the International Prospective Register of Systematic Reviews (PROSPERO). Registration number: CRD42021241596.

Risk factors and protective factors of acute postoperative pain: an observational study at a German university hospital with cross-sectional and longitudinal inpatient data

OBJECTIVES

Surgical fear is one of the most important psychological risk factors for postoperative pain, but less is known about the contribution of protective factors. This study investigated somatic and psychological risk and resilience factors of postoperative pain and validated the German version of the Surgical Fear Questionnaire (SFQ).

SETTING

University Hospital of Marburg, Germany.

DESIGN

Single-centre observational study and cross-sectional validation study.

PARTICIPANTS

Data for validating the SFQ were obtained from a cross-sectional observational study (N=198, mean age 43.6 years, 58.8% female) with persons undergoing different kinds of elective surgery. A sample of N=196 (mean age 43.0 years, 45.4% female) undergoing elective (orthopaedic) surgery was analysed to investigate somatic and psychological predictors of relevant acute postsurgical pain (APSP).

OUTCOME MEASURES

Participants completed preoperative and postoperative assessments at postoperative days 1, 2 and 7. Presurgical pain, age, gender, pain expectation, surgical setting, physical status, anaesthesia, surgical fear, pain catastrophising, depression, optimism and self-efficacy were examined as predictors.

RESULTS

Confirmatory factor analysis confirmed the original two-factor structure of the SFQ. Correlation analyses indicated good convergent and divergent validity. Internal consistency (Cronbach's α) was between 0.85 and 0.89. Blockwise logistic regression analyses for the risk of APSP revealed outpatient setting, higher preoperative pain, younger age, more surgical fear and low dispositional optimism as significant predictors.

CONCLUSIONS

The German SFQ is a valid, reliable and economical instrument with which the important psychological predictor surgical fear can be assessed. Modifiable factors that increase the risk of postoperative pain were higher pain intensity before surgery and being fearful about negative consequences of the surgery whereas positive expectations seem to buffer against postsurgical pain.

TRIAL REGISTRATION NUMBERS

DRKS00021764 and DRKS00021766.

Can perioperative psychological interventions reduce chronic pain after surgery?

Chronic post-surgical pain is a relatively common adverse effect following surgery. Several prognostic factors for chronic post-surgical pain have been identified, including psychological states and traits. Psychological factors are modifiable, and perioperative psychological interventions may reduce the incidence of chronic post-surgical pain. A meta-analysis showed preliminary evidence for the benefits of such interventions for the prevention of chronic post-surgical pain. Further research must be conducted to better understand the specific type, intensity, duration and timing of interventions that are most effective. The number of studies in this area has recently increased, with additional randomised controlled trials currently being carried out, which may allow for the development of more robust conclusions in the coming years. In order to implement perioperative psychological care alongside routine surgical interventions, efficient and accessible interventions should be available. In addition, demonstration of cost-effectiveness may be a prerequisite for wider adoption of perioperative psychological interventions in regular healthcare. Offering psychological interventions selectively to patients at risk of chronic post-surgical pain could be a means to increase cost-effectiveness. Stepped-care approaches should also be considered, where the intensity of psychological support is adapted to the needs of the patient.

The Peripheral Nerve Surgeon's Role in the Management of Neuropathic Pain

Neuropathic pain (NP) underlies significant morbidity and disability worldwide. Although pharmacologic and functional therapies attempt to address this issue, they remain incompletely effective for many patients. Peripheral nerve surgeons have a range of techniques for intervening on NP. The aim of this review is to enable practitioners to identify patients with NP who might benefit from surgical intervention. The workup for NP includes patient history and specific physical examination maneuvers, as well as imaging and diagnostic nerve blocks. Once diagnosed, there is a range of options surgeons can utilize based on specific causes of NP. These techniques include nerve decompression, nerve reconstruction, nerve ablative techniques, and implantable nerve-modulating devices. In addition, there is an emerging role for preoperative involvement of peripheral nerve surgeons for cases known to carry a high risk of inducing postoperative NP. Lastly, we describe the ongoing work that will enable surgeons to expand their armamentarium to better serve patients with NP.

Factors predicting the transition from acute to persistent pain in people with 'sciatica': the FORECAST longitudinal prognostic factor cohort study protocol

INTRODUCTION

Sciatica is a common condition and is associated with higher levels of pain, disability, poorer quality of life, and increased use of health resources compared with low back pain alone. Although many patients recover, a third develop persistent sciatica symptoms. It remains unclear, why some patients develop persistent sciatica as none of the traditionally considered clinical parameters (eg, symptom severity, routine MRI) are consistent prognostic factors.The FORECAST study (factors predicting the transition from acute to persistent pain in people with 'sciatica') will take a different approach by exploring mechanism-based subgroups in patients with sciatica and investigate whether a mechanism-based approach can identify factors that predict pain persistence in patients with sciatica.

METHODS AND ANALYSIS

We will perform a prospective longitudinal cohort study including 180 people with acute/subacute sciatica. N=168 healthy participants will provide normative data. A detailed set of variables will be assessed within 3 months after sciatica onset. This will include self-reported sensory and psychosocial profiles, quantitative sensory testing, blood inflammatory markers and advanced neuroimaging. We will determine outcome with the Sciatica Bothersomeness Index and a Numerical Pain Rating Scale for leg pain severity at 3 and 12 months.We will use principal component analysis followed by clustering methods to identify subgroups. Univariate associations and machine learning methods optimised for high dimensional small data sets will be used to identify the most powerful predictors and model selection/accuracy.The results will provide crucial information about the pathophysiological drivers of sciatica symptoms and may identify prognostic factors of pain persistence.

ETHICS AND DISSEMINATION

The FORECAST study has received ethical approval (South Central Oxford C, 18/SC/0263). The dissemination strategy will be guided by our patient and public engagement activities and will include peer-reviewed publications, conference presentations, social media and podcasts.

TRIAL REGISTRATION NUMBER

ISRCTN18170726; Pre-results.