The association between changes in clinical pain severity and IL-6 reactivity among patients undergoing total knee Arthroplasty: The moderating role of change in insomnia.

Knee osteoarthritis (KOA) is linked to an enhanced release of interleukin-6 (IL-6). Increased levels of IL-6 are associated with greater pain and insomnia. While total knee arthroplasty (TKA) typically results in the reduction of pain, for a subgroup of patients, pain does not improve. Understanding patients' propensity to upregulate IL-6 may provide insight into variation in the clinical success of TKA for improving pain, and insomnia may play an important modulatory role. We investigated the association between pre- and post-surgical changes in clinical pain and IL-6 reactivity, and whether change in insomnia moderated this association. Patients (n = 39) with KOA came in-person before and 3-months after TKA. At both visits, patients completed validated measures of clinical pain and insomnia, as well as underwent quantitative sensory testing (QST). Blood samples were collected to analyze IL-expression both before and after QST procedures to assess changes in IL-6 in response to QST (IL-6 reactivity). Patients were categorized into two groups based on change in clinical pain from pre- to post-surgery: 1) pain decreased > 2 points (pain improved) and 2) pain did not decrease > 2 points (pain did not improve). Based on this definition, 49 % of patients had improved pain at 3-months. Among patients with improved pain, IL-6 reactivity significantly decreased from pre- to post-surgery, whereas there was no significant change in IL-6 reactivity among those whose pain did not improve. There was also a significant interaction between pain status and change in insomnia, such that among patients whose insomnia decreased over time, improved pain was significantly associated with a reduction in IL-6 reactivity. However, among patients whose insomnia increased over time, pain status and change in IL-6 reactivity were not significantly associated. Our findings suggest that the resolution of clinical pain after TKA may be associated with discernible alterations in pro-inflammatory responses that can be measured under controlled laboratory conditions, and this association may be moderated by perioperative changes in insomnia. Randomized controlled trials which carefully characterize the phenotypic features of patients are needed to understand how and for whom behavioral interventions may be beneficial in modulating inflammation, pain, and insomnia.

Brief Assessment of Patient Phenotype to Explain Variability in Postsurgical Pain and Opioid Consumption after Cesarean Delivery: Performance of a Novel Brief Questionnaire Compared to Long Questionnaires.

BACKGROUND: Understanding factors that explain why some women experience greater postoperative pain and consume more opioids after cesarean delivery is crucial to building an evidence base for personalized prevention. Comprehensive psychosocial assessment with validated questionnaires in the preoperative period can be time-consuming. A three-item questionnaire has shown promise as a simpler tool to be integrated into clinical practice, but its brevity may limit the ability to explain heterogeneity in psychosocial pain modulators among individuals. This study compared the explanatory ability of three models: (1) the 3-item questionnaire, (2) a 58-item questionnaire (long) including validated questionnaires (e.g., Brief Pain Inventory, Patient Reported Outcome Measurement Information System [PROMIS]) plus the 3-item questionnaire, and (3) a novel 19-item questionnaire (brief) assessing several psychosocial factors plus the 3-item questionnaire. Additionally, this study explored the utility of adding a pragmatic quantitative sensory test to models. METHODS: In this prospective, observational study, 545 women undergoing cesarean delivery completed questionnaires presurgery. Pain during local anesthetic skin wheal before spinal placement served as a pragmatic quantitative sensory test. Postoperatively, pain and opioid consumption were assessed. Linear regression analysis assessed model fit and the association of model items with pain and opioid consumption during the 48 h after surgery. RESULTS: A modest amount of variability was explained by each of the three models for postoperative pain and opioid consumption. Both the brief and long questionnaire models performed better than the three-item questionnaire but were themselves statistically indistinguishable. Items that were independently associated with pain and opioid consumption included anticipated postsurgical pain medication requirement, surgical anxiety, poor sleep, pre-existing pain, and catastrophic thinking about pain. The quantitative sensory test was itself independently associated with pain across models but only modestly improved models for postoperative pain. CONCLUSIONS: The brief questionnaire may be more clinically feasible than longer validated questionnaires, while still performing better and integrating a more comprehensive psychosocial assessment than the three-item questionnaire.

Pain coping, multidisciplinary care, and mHealth: Patients' views on managing advanced cancer pain.

OBJECTIVE: Pain is common among people with advanced cancer. While opioids provide significant relief, incorporating psycho-behavioral treatments may improve pain outcomes. We examined patients' experiences with pain self-management and how their self-management of chronic, cancer-related pain may be complemented by behavioral mobile health (mHealth) interventions. METHODS: We conducted semi-structured qualitative interviews with patients with advanced cancer and pain. Each participant reviewed content from our behavioral mHealth application for cancer pain management and early images of its interface. Participants reflected on their experiences self-managing cancer pain and on app content. Interviews were transcribed verbatim and analyzed using a combination of inductive and deductive thematic analysis. RESULTS: Patients (n = 28; 54% female; mean age = 53) across two geographic regions reported using psychological strategies (e.g., reframing negative thoughts, distraction, pain acceptance, social support) to manage chronic cancer-related pain. Patients shared their perspectives on the integration of psycho-behavioral pain treatments into their existing medical care and their experiences with opioid hesitancy. Patient recommendations for how mHealth interventions could best support them coalesced around two topics: 1.) convenience in accessing integrated pharmacological and psycho-behavioral pain education and communication tools and 2.) relevance of the specific content to their clinical situation. CONCLUSIONS: Integrated pharmacological and psycho-behavioral pain treatments were important to participants. This underscores a need to coordinate complimentary approaches when developing cancer pain management interventions. Participant feedback suggests that an mHealth intervention that integrates pain treatments may have the capacity to increase advanced cancer patients' access to destigmatizing, accessible care while improving pain self-management.

A secondary analysis: the impact of pre-existing chronic pain among patients with cancer presenting to the emergency department with acute pain.

PURPOSE: Patients with cancer may experience pain from cancer itself or its treatment. Additionally, chronic pain (CP) predating a patient's cancer diagnosis may make the etiology of pain less clear and the management of pain more complex. In this brief report, we investigated differences in biopsychosocial characteristics, pain severity, and opioid consumption, comparing groups of cancer patients with and without a history of CP who presented to the emergency department (ED) with a complaint of cancer-related pain. METHODS: This secondary analysis of a prospective cohort study included patients with cancer who presented to the ED with a complaint of pain (≥ 4/10). Sociodemographic, clinical, psychological, and pain characteristics were assessed in the ED and subsequent hospitalization. Mann-Whitney U-, T-, and Chi-square tests were used to compare differences between patients with and without pre-existing CP before cancer. RESULTS: Patients with pre-existing CP had lower income (p = 0.21) and less formal education (p = 0.25) and were more likely to have a diagnosis of depression or substance use disorder (p < 0.01). Patients with pre-existing CP reported significantly greater pain severity in the ED and during hospitalization compared to those without pre-existing CP (p < 0.05), despite receiving greater amounts of opioid analgesics (p = 0.036). CONCLUSION: Identifying a history of pre-existing CP during intake may help identify patients with cancer with difficult to manage pain, who may particularly benefit from multimodal interventions and supportive care. In addition, referral of these patients for the management of co-occurring pain disorders may help decrease the usage of the ED for undertreated pain.

Development and pre-pilot testing of STAMP + CBT: an mHealth app combining pain cognitive behavioral therapy and opioid support for patients with advanced cancer and pain.

PURPOSE: We developed and piloted a mobile health app to deliver cognitive behavioral therapy for pain (pain-CBT), remote symptom monitoring, and pharmacologic support for patients with pain from advanced cancer. METHODS: Using an iterative process of patient review and feedback, we developed the STAMP + CBT app. The app delivers brief daily lessons from pain-CBT and pain psychoeducation, adapted for advanced cancer. Daily surveys assess physical symptoms, psychological symptoms, opioid utilization and relief. Just-in-time adaptive interventions generate tailored psychoeducation in response. We then conducted a single-arm pilot feasibility study at two cancer centers. Patients with advanced cancer and chronic pain used the app for 2 or 4 weeks, rated its acceptability and provided feedback in semi-structured interviews. Feasibility and acceptability were defined as ≥ 70% of participants completing ≥ 50% of daily surveys, and ≥ 80% of acceptability items rated ≥ 4/5. RESULTS: Fifteen participants (female = 9; mean age = 50.3) tested the app. We exceeded our feasibility and accessibility benchmarks: 73% of patients completed ≥ 50% of daily surveys; 87% of acceptability items were rated ≥ 4/5. Participants valued the app's brevity, clarity, and salience, and found education on stress and pain to be most helpful. The app helped participants learn pain management strategies and decrease maladaptive thoughts. However, participants disliked the notification structure (single prompt with one snooze), which led to missed content. CONCLUSION: The STAMP + CBT app was an acceptable and feasible method to deliver psychological/behavioral treatment with pharmacologic support for cancer pain. The app is being refined and will be tested in a larger randomized pilot study. TRN: NCT05403801 (05/06/2022).

Preoperative decreased physical activity is associated with greater postoperative pain: the mediating role of preoperative sleep disturbance.

PURPOSE: Engagement in physical activity (PA) is often associated with better sleep quality and less pain severity among patients diagnosed with breast cancer. However, less research has focused on whether patients' PA prior to breast surgery, including their perceived decrease in PA level, is associated with worse preoperative sleep quality, and subsequently, greater postoperative pain. This longitudinal study investigated whether patients' preoperative PA was associated with their postoperative pain. We also explored whether preoperative sleep disturbance partially mediated the relationship between preoperative PA and postoperative pain. METHODS: Prior to breast surgery, patients self-reported both their overall level of PA and whether they perceived a decrease in their PA since the diagnosis/onset of treatment for cancer. Patients also completed a measure of preoperative sleep disturbance. Two weeks after surgery, patients completed a measure of postoperative surgical-area pain severity. RESULTS: Our results showed that preoperatively perceiving a decrease in PA level was significantly associated with greater preoperative sleep disturbance and postoperative pain. A mediation analysis revealed that the association between preoperative decreased PA and postoperative pain was partially mediated by preoperative sleep disturbance. Notably, patients' overall preoperative level of PA was not related to preoperative sleep disturbance or postoperative pain. CONCLUSION: These findings suggest that maintaining, or even increasing, PA after diagnosis/treatment may be more important than the absolute amount of PA that women engage in during the preoperative period. Potentially, some patients with breast cancer may benefit from a preoperative intervention focused on both maintaining PA and bolstering sleep quality.

Individuals with fibromyalgia report greater pain sensitivity than healthy adults while listening to their favorite music: the contribution of negative affect.

OBJECTIVE: We investigated the impact of favorite music on pain processing among individuals with fibromyalgia. We also examined differences in pain processing between individuals with fibromyalgia and healthy controls (HC) while listening to favorite music and explored whether psychosocial factors contributed to these differences. METHODS: Individuals with fibromyalgia and HC completed baseline psychosocial questionnaires and then underwent quantitative sensory testing (QST) during 3 randomized music conditions (meditative music, favorite music, white noise). Among individuals with fibromyalgia, Friedman tests were used to investigate differences in QST across conditions. Analyses of Covariance were used to examine group (HC vs fibromyalgia) differences in QST during favorite music. Correlations were conducted to explore associations of baseline psychosocial factors with QST during favorite music. Mediation analyses were conducted to explore whether psychosocial factors contributed to greater pain sensitivity among individuals with fibromyalgia compared to HC during favorite music. RESULTS: Individuals with fibromyalgia were less sensitive to pressure pain while listening to their favorite music compared to white noise. Compared to HC, individuals with fibromyalgia reported higher baseline negative affect and lower pain thresholds and tolerances during favorite music. Negative affect partially mediated the relationship between pain status (HC vs fibromyalgia) and pain sensitivity during favorite music. CONCLUSIONS: Individuals with fibromyalgia were less pain sensitive while listening to favorite music than white noise, although they were more sensitive than HC. Greater negative affect endorsed by individuals with fibromyalgia contributed to their greater pain sensitivity. Future studies should explore the impact of favorite music on clinical pain. CLINICAL TRAILS REGISTRATION: This study was registered with ClinicalTrials.gov (NCT04087564) and began on 6/13/2019.

A Mixed-Methods study of the impact of sex and situational pain catastrophizing on pain sensitivity.

BACKGROUND: It is well established that catastrophic thinking about pain modulates clinical pain severity, but it may also relate to interindividual differences in the pain experience during procedures. This mixed-methods study investigated the relationship between ratings of situational pain catastrophizing and reported pain sensitivity in the context of receiving a nerve block without sedation, and explored participants' experiences. METHODS: Healthy volunteers (n = 42) completed baseline psychosocial questionnaires, underwent quantitative sensory testing, and received a lower extremity nerve block, followed by further psychosocial assessment and interviews. Associations of catastrophizing scores with pain sensitivity and procedural site pain were assessed using Spearman's correlations. Interviews were reviewed using an immersion/crystallization approach to identify emergent themes. RESULTS: Greater situational catastrophizing scores were associated with higher pain sensitivity, measured as lower pain threshold and tolerance. Although females exhibited greater pain sensitivity generally, moderation analysis revealed a significant association between situational catastrophizing scores and pain sensitivity only among male participants. Qualitative interviews revealed the importance of participants' emotional responses to pain, and a mismatch of expectation and experience with procedural pain. Males also reported more negative comments about procedural pain. DISCUSSION: Examination of the variable subjective experience while receiving a nerve block in this experimental lab-based study revealed an important relationship between situational pain catastrophizing scores and pain sensitivity, which was more prominent among male participants. These findings reinforce how insight into individual expectations, emotions, and thought processes may impact pain sensitivity during procedures, and may inform strategies to personalize care, improving patient satisfaction and procedural acceptance.

Pain Severity and Pain Interference in Late Pregnancy: An Analysis of Biopsychosocial Factors Among Women Scheduled for Cesarean Delivery.

OBJECTIVE: Pain is a variably experienced symptom during pregnancy, and women scheduled for cesarean delivery, an increasingly common procedure, are a relatively understudied group who might be at higher pain risk. Although biopsychosocial factors are known to modulate many types of chronic pain, their contribution to late pregnancy pain has not been comprehensively studied. We aimed to identify biopsychosocial factors associated with greater pain severity and interference during the last week of pregnancy. METHODS: In this prospective, observational study, 662 pregnant women scheduled for cesarean delivery provided demographic and clinical information and completed validated psychological and pain assessments. Multivariable hierarchical linear regressions assessed independent associations of demographic, clinical, and psychological characteristics with pain severity and pain interference during the last week of pregnancy. RESULTS: Women in the study had a mean age of 34 years, and 73% identified as White, 11% as African American, 10% as Hispanic/Latina, and 6% as Asian. Most women (66%) were scheduled for repeat cesarean delivery. Significant independent predictors of worse pain outcomes included identifying as African American or Hispanic/Latina and having greater depression, sleep disturbance, and pain catastrophizing. Exploratory analyses showed that women scheduled for primary (versus repeat) cesarean delivery reported higher levels of anxiety and pain catastrophizing. CONCLUSIONS: Independent of demographic or clinical factors, psychological factors, including depression, sleep disturbance, and pain catastrophizing, conferred a greater risk of late pregnancy pain. These findings suggest that women at higher risk of pain during late pregnancy could benefit from earlier nonpharmacological interventions that concurrently focus on psychological and pain symptoms.

Brief Mindfulness-Based Cognitive Behavioral Therapy is Associated with Faster Recovery in Patients Undergoing Total Knee Arthroplasty: A Pilot Clinical Trial.

OBJECTIVE: To assess whether brief mindfulness-based cognitive behavioral therapy (MBCBT) could enhance the benefits of total knee arthroplasty (TKA) in improving pain and pain-related disability. Specifically, to determine 1) whether patients who received MBCBT differed from matched controls who received treatment-as-usual with regard to postsurgical pain outcomes and 2) whether changes in pain catastrophizing, depression, or anxiety explained the potential effects of MBCBT on pain outcomes. DESIGN: Pilot clinical trial. SETTING: An academic teaching hospital serving a large urban and suburban catchment area surrounding the Boston, Massachusetts metropolitan region. SUBJECTS: Sample of 44 patients undergoing TKA. Patients who completed a brief MBCBT intervention (n = 22) were compared with age-, race-, and sex-matched controls who received treatment-as-usual (n = 22). METHODS: The MBCBT intervention included four 60-minute sessions delivered by a pain psychologist in person and via telephone during the perioperative period. Participants were assessed at baseline and at 6 weeks, 3 months, and 6 months after surgery. RESULTS: Compared with matched controls, patients who received MBCBT had lower pain severity and pain interference at 6 weeks after surgery. Group differences in outcomes were mediated by changes in pain catastrophizing but not by changes in depression or anxiety. The MBCBT group had similar reductions in pain severity and interference as the control group did at 3 and 6 months after surgery. CONCLUSIONS: This work offers evidence for a safe and flexibly delivered nonpharmacological treatment (MBCBT) to promote faster recovery from TKA and identifies change in pain catastrophizing as a mechanism by which this intervention could lead to enhanced pain-related outcomes.

Introversion, Extraversion, and Worsening of Chronic Pain Impact during Social Isolation: A Mediation Analysis.

COVID-19 social distancing mandates increased social isolation, resulting in changes in pain severity and interference among individuals with chronic pain. Differences in personality (e.g., introversion/extraversion) may modulate responses to social isolation. We examined the influence of introversion on reported social distancing-related increases in pain interference and assessed for mediators of this relationship. Individuals with chronic pain (n = 150) completed validated questionnaires 4-8 weeks after implementation of social distancing mandates. Introversion/extraversion was measured using a subscale of the Myers-Briggs Type Indicator and changes in pain and psychosocial variables were calculated by comparing participants' recalled and current scores. Association between introversion/extraversion and other variables were assessed using linear regression. A parallel mediation was used to examine mediators of the association between introversion and change in pain interference. Higher introversion was associated with a decrease in pain interference after social distancing (Rho = - .194, p = .017). Parallel mediation analysis revealed that the relationship between introversion/extraversion and change in pain interference was mediated by changes in sleep disturbance and depression, such that higher introversion was associated with less isolation-induced sleep disruption and depression, and thereby less worsening of pain interference. These findings suggest that personality factors such as introversion/extraversion should be considered when personalizing treatment of chronic pain.

Early postoperative psychological distress as a mediator of subsequent persistent postsurgical pain outcomes among younger breast cancer patients.

PURPOSE: Younger age is a risk factor for worse pain outcomes following breast cancer surgery, yet little is known about how younger women's psychological state may contribute to their pain experience. Using prospectively collected longitudinal data from a surgical cohort, we examined whether early postoperative psychological distress at 2 weeks mediated the association between younger age and subsequent worse pain-related functioning 3 months after surgery. METHODS: Patients (N = 159) were recruited before breast cancer surgery into this longitudinal cohort study. Age at time of surgery, psychological distress (anxiety, depression, and sleep disturbance) assessed 2 weeks postoperatively, and impact of surgical pain on cognitive/emotional functioning and physical functioning assessed 3 months postoperatively were used for analysis. RESULTS: Younger age was associated with greater depression, anxiety, and sleep disturbance 2 weeks postoperatively. Younger age was also associated with greater ratings of pain impacting cognitive/emotional functioning and physical functioning 3 months postoperatively. The association between younger age and worse cognitive/emotional impact of pain was mediated by greater anxiety and sleep disturbance. Similarly, the association between younger age and worse physical impact of pain was mediated by greater sleep disturbance. CONCLUSION: The degree of anxiety and sleep disturbance that occur early after breast surgery may contribute to greater chronic pain-related functional disability among younger patients. Anxiety and sleep disturbance are modifiable with behavioral interventions, making them potential perioperative targets to improve long-term outcomes in young breast cancer survivors.

Increased pain catastrophizing longitudinally predicts worsened pain severity and interference in patients with chronic pain and cancer: A collaborative health outcomes information registry study (CHOIR).

OBJECTIVE: Little is known about how changes in psychosocial factors impact changes in pain outcomes among patients with cancer and chronic pain. This longitudinal cohort study of cancer patients investigated the relationships between changes in psychosocial factors and changes in pain severity and interference over time. METHODS: Data from patients with cancer and chronic pain (n = 316) treated at a tertiary pain clinic were prospectively collected. At their baseline visit (Time 1), patients provided demographic and clinical information, and completed validated psychosocial and pain assessments. Psychosocial and pain assessments were repeated at a follow-up visit (Time 2), on average 4.9 months later. Change scores (Time 2-Time 1) were computed for psychosocial and pain variables. Multivariable hierarchical linear regressions assessed the associations between changes in psychosocial factors with changes in pain outcomes over time. RESULTS: Participants were an average age of 59 years, were 61% female, and 69% White. Overall, a decrease in pain severity (p ≤ 0.001), but not pain interference, was observed among the group over time. In multivariable analyses, increased pain catastrophizing was significantly associated with increased pain severity over time (ß = 0.24, p ≤ 0.001). Similarly, increased pain catastrophizing (ß = 0.21, p ≤ 0.001) and increased depression (ß = 0.20, p ≤ 0.003) were significantly associated with increased pain interference over time. Demographic and clinical characteristics were not significantly related to changes in pain outcomes. CONCLUSIONS: Increased pain catastrophizing was uniquely associated with increased chronic pain severity and interference. Our findings indicate that cancer patients with chronic pain would likely benefit from the incorporation of nonpharmacological interventions, simultaneously addressing pain and psychological symptoms.

Profiles of Risk and Resilience in Chronic Pain: Loneliness, Social Support, Mindfulness, and Optimism Coming out of the First Pandemic Year.

OBJECTIVE: Individuals experience chronic pain differently, not only because of different clinical diagnoses, but also because of differing degrees of influence from biopsychosocial pain modulators. We aimed to cluster patients with chronic pain into distinct subgroups based on psychosocial characteristics and pain intensity, and we subsequently examined group differences in pain-related interference approximately 1 year later. METHODS: In this observational, longitudinal study, patients with chronic pain (n = 94) completed validated assessments of psychosocial characteristics and pain intensity at the beginning of COVID-19-related social distancing (April to June 2020). One year later (May to June 2021), patients completed a follow-up survey with assessments of pain interference, loneliness, social support, mindfulness, and optimism. RESULTS: A cluster analysis, using psychosocial factors and pain intensity, empirically produced three patient groups: 1) psychosocial predominant (PSP), characterized by high psychosocial distress and average pain intensity; 2) pain intensity predominant (PIP), characterized by average psychosocial distress and high pain intensity; and 3) less elevated symptoms (LES), characterized by low psychosocial distress and low pain intensity. At the 1-year follow-up, patients in the PSP and PIP clusters suffered greater pain interference than patients in the LES cluster, while patients in the PSP cluster also reported greater loneliness and lower mindfulness and optimism. CONCLUSIONS: An empirical psychosocial-based clustering of patients identified three distinct groups that differed in pain interference. Patients with high psychosocial modulation of pain at the onset of social distancing (the PSP cluster) suffered not only greater pain interference but also greater loneliness and lower levels of mindfulness and optimism, which suggests some potential behavioral targets for this group in the future.

Multimodal prediction of pain and functional outcomes 6 months following total knee replacement: a prospective cohort study.

BACKGROUND: Knee osteoarthritis (OA) is among the most common and disabling persistent pain conditions, with increasing prevalence and impact around the globe. In the U.S., the rising prevalence of knee OA has been paralleled by an increase in annual rates of total knee arthroplasty (TKA), a surgical treatment option for late-stage knee OA. While TKA outcomes are generally good, post-operative trajectories of pain and functional status vary substantially; a significant minority of patients report ongoing pain and impaired function following TKA. A number of studies have identified sets of biopsychosocial risk factors for poor post-TKA outcomes (e.g., comorbidities, negative affect, sensory sensitivity), but few prospective studies have systematically evaluated the unique and combined influence of a broad array of factors. METHODS: This multi-site longitudinal cohort study investigated predictors of 6-month pain and functional outcomes following TKA. A wide spectrum of relevant biopsychosocial predictors was assessed preoperatively by medical history, patient-reported questionnaire, functional testing, and quantitative sensory testing in 248 patients undergoing TKA, and subsequently examined for their predictive capacity. RESULTS: The majority of patients had mild or no pain at 6 months, and minimal pain-related impairment, but approximately 30% reported pain intensity ratings of 3/10 or higher. Reporting greater pain severity and dysfunction at 6 months post-TKA was predicted by higher preoperative levels of negative affect, prior pain history, opioid use, and disrupted sleep. Interestingly, lower levels of resilience-related "positive" psychosocial characteristics (i.e., lower agreeableness, lower social support) were among the strongest, most consistent predictors of poor outcomes in multivariable linear regression models. Maladaptive profiles of pain modulation (e.g., elevated temporal summation of pain), while not robust unique predictors, interacted with psychosocial risk factors such that the TKA patients with the most pain and dysfunction exhibited lower resilience and enhanced temporal summation of pain. CONCLUSIONS: This study underscores the importance of considering psychosocial (particularly positively-oriented resilience variables) and sensory profiles, as well as their interaction, in understanding post-surgical pain trajectories.

Social Support and Psychological Distress among Chronic Pain Patients: The Mediating Role of Mindfulness.

Although an inverse relation between social support and psychological distress among chronic pain patients has been previously reported, little is known about what mediates this association. We examined mindfulness as a mediator of the relationship between social support and psychological distress. In this cross-sectional study, chronic pain patients (N=94) completed assessments of social support, mindfulness, and psychological distress. Greater social support was associated with less psychological distress. Greater mindfulness was associated with greater social support and less psychological distress. Mediation analyses demonstrated that mindfulness partially mediated the relationship between social support and psychological distress. Findings support and extend prior research by demonstrating a potentially important mediating effect of mindfulness within chronic pain patients. This suggests an important link between social support and mindfulness, and that their integration in the pursuit of mental health should be considered in future behavioral interventions.

Prediction of Persistent Pain Severity and Impact 12 Months After Breast Surgery Using Comprehensive Preoperative Assessment of Biopsychosocial Pain Modulators.

BACKGROUND: Persistent post-mastectomy pain (PPMP) is a significant negative outcome occurring after breast surgery, and understanding which individual women are most at risk is essential to targeting of preventive efforts. The biopsychosocial model of pain suggests that factors from many domains may importantly modulate pain processing and predict the progression to pain persistence. METHODS: This prospective longitudinal observational cohort study used detailed and comprehensive psychosocial and psychophysical assessment to characterize individual pain-processing phenotypes in 259 women preoperatively. Pain severity and functional impact then were longitudinally assessed using both validated surgery-specific and general pain questionnaires to survey patients who underwent lumpectomy, mastectomy, or mastectomy with reconstruction in the first postsurgical year. An agnostic, multivariable modeling strategy identified consistent predictors of several pain outcomes at 12 months. RESULTS: The preoperative characteristics most consistently associated with PPMP outcomes were preexisting surgical area pain, less education, increased somatization, and baseline sleep disturbance, with axillary dissection emerging as the only consistent surgical variable to predict worse pain. Greater pain catastrophizing, negative affect, younger age, higher body mass index (BMI), and chemotherapy also were independently predictive of pain impact, but not severity. Sensory disturbance in the surgical area was predicted by a slightly different subset of factors, including higher preoperative temporal summation of pain. CONCLUSIONS: This comprehensive approach assessing consistent predictors of pain severity, functional impact, and sensory disturbance may inform personalized prevention of PPMP and also may allow stratification and enrichment in future preventive studies of women at higher risk of this outcome, including pharmacologic and behavioral interventions and regional anesthesia.

Procedure-specific acute pain trajectory after elective total hip arthroplasty: systematic review and data synthesis.

BACKGROUND: For most procedures, there is insufficient evidence to guide clinicians in the optimal timing of advanced analgesic methods, which should be based on the expected time course of acute postoperative pain severity and aimed at time points where basic analgesia has proven insufficient. METHODS: We conducted a systematic search of the literature of analgesic trials for total hip arthroplasty (THA), extracting and pooling pain scores across studies, weighted for study size. Patients were grouped according to basic anaesthetic method used (general, spinal), and adjuvant analgesic interventions such as nerve blocks, local infiltration analgesia, and multimodal analgesia. Special consideration was given to high-risk populations such as chronic pain or opioid-dependent patients. RESULTS: We identified and analysed 71 trials with 5973 patients and constructed pain trajectories from the available pain scores. In most patients undergoing THA under general anaesthesia on a basic analgesic regimen, postoperative acute pain recedes to a mild level (<4/10) by 4 h after surgery. We note substantial variability in pain intensity even in patients subjected to similar analgesic regimens. Chronic pain or opioid-dependent patients were most often actively excluded from studies, and never analysed separately. CONCLUSIONS: We have demonstrated that it is feasible to construct procedure-specific pain curves to guide clinicians on the timing of advanced analgesic measures. Acute intense postoperative pain after THA should have resolved by 4-6 h after surgery in most patients. However, there is a substantial gap in knowledge on the management of patients with chronic pain and opioid-dependent patients.

Persistent Post-Mastectomy Pain: The Impact of Regional Anesthesia Among Patients with High vs Low Baseline Catastrophizing.

BACKGROUND: Persistent post-mastectomy pain (PPMP) varies both in its severity and impact, with psychosocial factors such as catastrophizing conferring greater risk. Preoperative regional anesthesia (RA) is an important nonopioid therapy, but with variable success at preventing PPMP in previous reports. We previously reported that RA was associated with lower acute post-mastectomy pain and opioid use, but more prominently among patients with higher baseline catastrophizing. The current longitudinal investigation at 3, 6, and 12 months postop aimed to detect differential long-term impact of RA on PPMP among patients with high vs low catastrophizing. METHODS: In this prospective observational study, patients (n = 123) completed preoperative psychosocial assessment and underwent mastectomy either with (n = 56) or without (n = 67) preoperative RA. Generalized estimating equation (GEE) regression analysis assessed impact of baseline catastrophizing, RA, and their interaction, on the primary outcome of pain severity index, as well as secondary outcomes including cognitive and emotional impact of pain, and persistent opioid use. RESULTS: We observed a significant interaction between the effect of catastrophizing and RA on PPMP. Specifically, RA was associated with reduced pain severity and pain impact 3, 6, and 12 months postoperatively, but only among those with high baseline catastrophizing scores. In addition, both RA and lower catastrophizing scores were associated with lower incidence of persistent opioid use. CONCLUSIONS: The efficacy of therapies to prevent PPMP may be importantly influenced by pain-modulatory psychosocial characteristics. These findings underscore the importance of considering individual patient factors when applying preventive treatments, and of including their assessment in future trials.

Ultrasound-guided supraclavicular vs. retroclavicular block of the brachial plexus: comparison of ipsilateral diaphragmatic function: A randomised clinical trial.

BACKGROUND: The ultrasound-guided retroclavicular block (RCB) is a recently described alternative approach to brachial plexus blockade at the level of the cords. Although more distal blockade of the brachial plexus is thought to be associated with a lower incidence of phrenic nerve block, the impact of RCB on ipsilateral diaphragmatic function has not been formally investigated. OBJECTIVE: To compare the effects of supraclavicular and retroclavicular brachial plexus block on diaphragmatic function. SETTING: A single tertiary hospital, study period from December 2017 to May 2019. DESIGN: Double-blinded, randomised study. PATIENTS: A total of 40 patients undergoing upper extremity surgery below the axilla. Exclusion criteria included significant pulmonary disease, BMI more than 40 and contra-indication to peripheral nerve block. INTERVENTIONS: Patients were randomised to supraclavicular or retroclavicular brachial plexus block with ropivacaine 0.5%. OUTCOME MEASURES: Phrenic block was assessed by measuring changes in diaphragmatic excursion using M-mode ultrasound, and maximum inspiratory volume on incentive spirometry from baseline, at 15 and 30 min postblock, and postoperatively. Comparative assessment of block characteristics included timing and distribution of sensory and motor block onset in the upper extremity, and scanning and block performance times. RESULTS: The incidence of phrenic block in the supraclavicular group was higher by ultrasound imaging (70 vs. 15%) and also by pulmonary function testing (55 vs. 5%), with both diaphragmatic excursion and maximum inspiratory volume decreasing to a greater extent after supraclavicular block (SCB) compared with RCB at 15, 30 min and postoperative time points (repeated measures analysis of variance, P < 0.001). There was no difference in timing and extent of distal arm block, but suprascapular and axillary nerves were more consistently blocked after SCB than after RCB. CONCLUSION: The current study confirms the hypothesis that a RCB is significantly less likely to affect ipsilateral diaphragmatic function than a SCB. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02631122.