Emotional numbing and pain intensity predict the development of pain disability up to one year after lateral thoracotomy

Ten years of transitional pain service research and practice: where are we and where do we go from here?

Chronic postsurgical pain (CPSP) is a prevalent yet unintended consequence of surgery with substantial burdens to the individual and their family, the healthcare system, and society at large. The present article briefly reviews the evidence for transitional pain services (TPSs) that have arisen in an effort to prevent and mange CPSP and persistent opioid use, and provides an update on recent novel risk factors for CPSP. Available evidence from one randomized controlled trial (RCT) and three non-randomized cohort studies suggests that TPS treatment is associated with better opioid use outcomes, including fewer opioid tablets prescribed at discharge, better opioid weaning results, a lower incidence of new-onset chronic opioid use, and lower consumption of opioids even at later time points up to 1 year after surgery. Another RCT indicates TPS treatment can be enhanced by provision of perioperative clinical hypnosis. While these preliminary studies are generally positive, large-scale, RCTs are needed to provide a more definitive picture of whether TPSs are effective in reducing opioid consumption and improving pain and mental health outcomes in the short and long term. With the expansion of TPSs across North America and globally, perioperative care focused on reducing the transition to pain chronicity has the potential to help millions of patients. With additional evidence from well-controlled RCTs, TPSs are well poised to continue to evolve and strengthen the role of multidisciplinary care teams in the immediate postdischarge period and beyond.

MMPI-2-RF Profiles of Treatment-Seeking Veterans in a VA Pain Clinic and Associations with Markers of Physical Performance

Chronic pain is a debilitating condition for many military Veterans and is associated with posttraumatic stress disorder (PTSD). This study examined the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) in 144 Veterans (88.2% male, mean age = 57.95 years) recruited from a VA outpatient pain clinic and associations with self-reported pain severity, pain-related interference in daily activities, prescription opioid use, and objective metrics of physical performance on tasks impacted by pain (walking, stair climbing, grip strength, indexed by a single latent variable). Among the cohort with valid responses on the MMPI-2-RF (n = 117) and probable PTSD, mean Somatic Complaints (RC1) and Ideas of Persecution (RC6) scores were clinically elevated. All MMPI-2-RF scales were more strongly correlated with self-reported pain interference than severity. Regressions revealed associations between self-rated pain interference (but not pain or PTSD severity) and physical performance scores (β = .36, p = .001). MMPI-2-RF overreporting Validity and Higher-Order scales contributed incremental variance in predicting physical performance, including Infrequent Psychopathology Responses (β = .33, p = .002). PTSD severity was associated with prescription opioid use when accounting for the effects of over-reported somatic and cognitive symptoms (odds ratio 1.05, p ≤ .025). Results highlight the role of symptom overreporting and perceptions of functional impairment to observable behaviors among individuals with chronic pain.

Medical Cannabis Use and Inflammatory Cytokines and Chemokines Among Adult Chronic Pain Patients

Background: Utilizing cannabis as a therapeutic option for chronic pain (CP) has increased significantly. However, data regarding the potential immunomodulatory effects of cannabis in CP patients remain scarce. We aimed at exploring the relationship between cannabis use and inflammatory cytokines and chemokines among a cohort of CP patients. Methods: Adult patients with a CP diagnosis and medical authorization of cannabis were enrolled. Patients completed validated clinical questionnaires and self-reported the effectiveness of cannabis for symptom management. Patients' blood and cannabis samples were analyzed for the presence of four major cannabinoids, two major cannabinoid metabolites, 29 different cytokines/chemokines, and cortisol. The multivariable linear regression model was used to identify cannabis and patient factors associated with immune markers. Results: Fifty-six patients (48±15 years; 64% females) were included, with dried cannabis (53%) being the most common type of cannabis consumed. Seventy percent of products were considered delta-9-tetrahydrocannabinol (Δ9-THC)-dominant. The majority of patients (96%) self-reported effective pain management, and 76% reported a significant decrease in analgesic medication usage (p≤0.001). Compared with males, female patients had higher plasma levels of cannabidiol (CBD), cannabidiolic acid, Δ9-THC, and 11-hydroxy-Δ9-tetrahydrocannabinol but lower concentrations of delta-9-tetrahydrocannabinolic acid and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH). Females had significantly lower eotaxin levels (p=0.04) in comparison to male patients. The regression analysis indicated that high cannabis doses were related to increased levels of interleukin (IL)-12p40 (p=0.02) and IL-6 (p=0.01), whereas female sex was associated with decreased eotaxin (p≤0.01) concentrations. Blood CBD levels were associated with lower vascular endothelial growth factor (p=0.04) concentrations, and THC-COOH was a factor related to decreased tumor necrosis factor alpha (p=0.02) and IL-12p70 (p=0.03). Conclusion: This study provides further support for the patient-perceived effectiveness of cannabis in managing CP symptoms and reducing analgesic medication consumption. The results suggest a potential sex difference in metabolizing cannabinoids, and the varying immune marker concentrations may support a possible immunomodulatory effect associated with patient sex and cannabis product type. These preliminary findings provide grounds for further validation using larger, well-designed studies with longer follow-up periods.

Prevalence and Risk Factors for Chronic Postsurgical Pain After Thoracic Surgery: A Prospective Cohort Study

OBJECTIVE

Thoracic surgery is associated with one of the highest rates of chronic postsurgical pain (CPSP) among all surgical subtypes. Chronic postsurgical pain carries significant medical, psychological, and economic consequences, and further interventions are needed to prevent its development. This study aimed to determine the prevalence, characteristics, and risk factors associated with CPSP after thoracic surgery.

DESIGN

A prospective cohort study.

SETTING

Single-center tertiary care hospital.

PARTICIPANTS

This study included 285 adult patients who underwent thoracic surgery at Toronto General Hospital in Toronto, Canada, between 2012 and 2020.

MEASUREMENTS AND MAIN RESULTS

Demographic, psychological, and clinical data were collected perioperatively, and follow-up evaluations were administered at 3, 6, and 12 months after surgery to assess CPSP. Chronic postsurgical pain was reported in 32.4%, 25.4%, and 18.2% of patients at 3, 6, and 12 months postoperatively, respectively. Average CPSP pain intensity was rated to be 3.37 (SD 1.82) at 3 months. Features of neuropathic pain were present in 48.7% of patients with CPSP at 3 months and 71% at 1 year. Multivariate logistic regression models indicated that independent predictors for CPSP at 3 months were scores on the Hospital Anxiety and Depression Scale (adjusted odds ratio [aOR] of 1.07, 95% CI of 1.02 to 1.14, p = 0.012) and acute postoperative pain (aOR of 2.75, 95% CI of 1.19 to 6.36, p = 0.018).

INTERVENTIONS

None.

CONCLUSIONS

Approximately 1 in 3 patients will continue to have pain at 3 months after surgery, with a large proportion reporting neuropathic features. Risk factors for pain at 3 months may include preoperative anxiety and depression and acute postoperative pain.

Unresolved early post-operative pain trajectory predicts moderate-to-severe persistent pain after breast cancer surgery-An observational cohort study

BACKGROUND

Modelling acute post-operative pain trajectories may improve the prediction of persistent pain after breast cancer surgery (PPBCS). This study aimed to investigate the predictive accuracy of early post-operative pain (EPOP) trajectories in the development of PPBCS.

MATERIALS & METHODS

This observational study was conducted in a French Comprehensive Cancer Centre and included patients who underwent breast cancer surgery from December 2017 to November 2018. Perioperative and follow-up data were obtained from medical records, and anaesthesia and perioperative charts. EPOP was defined as pain intensity during the first 24 h after surgery, and modelled by a pain trajectory. K-means clustering method was used to identify patient subgroups with similar EPOP trajectories. The prevalence of moderate-to-severe PPBCS (numeric rating scale ≥4) was evaluated until 24 months after surgery.

RESULTS

A total of 608 patients were included in the study, of which 18% (n = 108) and 9% (n = 52) reported mild and moderate-to-severe PPBCS, respectively. Based on EPOP trajectories, we were able to identify a low (64%, n = 388), resolved (30%, n = 182), and unresolved (6%, n = 38) pain group. Multivariate analysis identified younger age, axillary lymph node dissection, and unresolved EPOP trajectory as independent risk factors for moderate-to-severe PPBCS development. When compared to patients reporting mild PPBCS, moderate-to-severe PPBCS patients experienced significantly more neuropathic pain features, pain-related interference, and delayed opioid cessation.

CONCLUSION

EPOP trajectories can distinguish between resolved and unresolved acute pain after breast cancer surgery, allowing early identification of patients at risk to develop significant PPBCS.

The role of post-trauma stress symptoms in the development of chronic musculoskeletal pain and disability: A systematic review

BACKGROUND AND OBJECTIVE

Traumatic injuries are amongst the leading causes of death and disability in the world across all age groups. This systematic review aimed to (1) describe the role of post-traumatic stress symptoms (PTSS) on the development of chronic pain and/or pain-related disability following musculoskeletal trauma and (2) report pain and or pain-related disability by injury severity/type.

DATABASE AND DATA TREATMENT

Electronic databases were searched, from inception to 31 November 2021 and updated on 10 May 2022, to identify studies in which: participants were adults aged ≥16 years sustaining any traumatic event that resulted in one or more musculoskeletal injuries; an outcome measure of PTSS was used within 3 months of a traumatic event; the presence of pain and/or pain-related disability was recorded at a follow-up of 3 months or more. Two reviewers independently screened papers and assessed the quality of included studies.

RESULTS

Eight studies were included. Owing to between-study heterogeneity, the results were synthesized using a narrative approach. Five studies investigated the relationship between PTSS and pain. Participants with PTSS were more likely to develop persistent pain for at least 12 months post-injury. Six studies assessed the relationship between PTSS and pain-related disability. The results suggest that patients with PTSS had significantly higher disability levels for at least 12 months post-injury.

CONCLUSION

Findings from this comprehensive systematic review support a clear relationship between PTSS post-injury and future pain/disability, with the potential importance of certain PTSS clusters (hyper-arousal and numbing).

SIGNIFICANCE

The findings of this systematic review indicate an association between PTSS reported within 3 months of a traumatic musculoskeletal injury and the development of longer-term pain and disability. The PTSS clusters of 'hyper-arousal' and 'numbing' appear to be of particular importance in this relationship.

PROSPERO REGISTRATION NUMBER

CRD42021285243.

Posttraumatic Stress Disorder Symptom Clusters as Predictors of Pain Interference in Burn Survivors: A Burn Model System National Database Study

Individuals who experience burns are at higher risk of developing posttraumatic stress disorder and chronic pain. A synergistic relationship exists between posttraumatic stress disorder and chronic pain. We sought to evaluate the role of individual posttraumatic stress disorder symptom clusters as predictors of pain interference. We hypothesized that the hyperarousal and emotional numbing symptom clusters would be predictive of pain interference, even when accounting for the other two posttraumatic stress disorder symptom clusters, pain intensity, and other covariates. Multivariate linear regression analyses were completed using data from the Burn Model System National Database. A total of 439 adult participants had complete responses on self-report measures assessing posttraumatic stress disorder symptoms, pain intensity, and pain interference at 6-month after discharge and were included in analyses. Results indicate hyperarousal (B = .10, p = .03) and emotional numbing (B = .13, p = .01) posttraumatic stress disorder symptom clusters were each significantly associated with pain interference, even when accounting for pain intensity (B = .64, p < .001). Results highlight the importance of the emotional numbing and hyperarousal posttraumatic stress disorder symptom clusters in explaining pain interference. Findings suggest that when posttraumatic stress disorder symptoms or chronic pain are present, screening for and treating either condition may be warranted to reduce pain interference. Further, psychological interventions that target emotional numbing and hyperarousal posttraumatic stress disorder symptoms may be fruitful for promoting better coping with chronic pain and reducing pain interference.

Emotional numbing in PTSD is associated with lower amygdala reactivity to pain

Posttraumatic stress disorder (PTSD) is associated with altered pain perception, namely increased pain threshold and higher pain response. While pain consists of physiological and affective components, affective components are often overlooked. Similar patterns of increased threshold-high response in PTSD were shown in response to emotional stimuli, i.e., emotional numbing. As both emotional numbing and pain processing are modulated by the amygdala, we aimed to examine whether individuals diagnosed with PTSD show lower amygdala activation to pain compared with combat controls, and whether the amygdala responses to pain correlates with emotional numbing. To do so, two independent samples of veterans (original study: 44 total (20 PTSD); conceptual replication study: 40 total (20 PTSD)) underwent threat conditioning, where a conditioned stimulus (CS+; visual stimulus) was paired with an unconditioned stimulus (US; electric-shock). We contrasted the amygdala activity to the CS + US pairing with the CS+ presented alone and correlated it with emotional numbing severity. In both samples, the PTSD group showed a robust reduction in amygdala reactivity to shock compared to the Combat Controls group. Furthermore, amygdala activation was negatively correlated with emotional numbing severity. These patterns were unique to the amygdala, and did not appear in comparison to a control region, the insula, a pivotal region for the processing of pain. To conclude, amygdala response to pain is lower in individuals with PTSD, and is associated with emotional numbing symptoms. Lower amygdala reactivity to mild pain may contribute to the "all-or-none" reaction to stressful situations often observed in PTSD.

Predictive Validity and Patterns of Change Over Time of the Sensitivity to Pain Traumatization Scale: A Trajectory Analysis of Patients Seen by the Transitional Pain Service Up to Two Years After Surgery

Purpose

The Sensitivity to Pain Traumatization Scale (SPTS-12) was developed to assess the propensity to develop a traumatic stress response to pain. The SPTS-12 is a reliable and valid scale with a one-factor structure. The aim of the present study is to further examine the psychometric properties of the SPTS-12 by evaluating its criterion validity and how scores change over time in a sample of postsurgical patients at the Toronto General Hospital Transitional Pain Service.

Participants and Methods

361 adults (55% male; M_age = 50.6 years, SD_age = 14.3) completed questionnaires assessing symptoms of pain, anxiety, depression, and trauma at multiple visits to the Transitional Pain Service after surgery. Latent-class growth mixture modeling defined prototypical longitudinal patterns (latent trajectories) of SPTS-12 scores up to two years after surgery. One-way ANOVAs examined how trajectory classes differed over time on measures of daily opioid use (mg morphine equivalents (MME)), average pain intensity, pain interference, and depressive symptoms.

Results

The final model consisted of five SPTS-12 trajectory groups; two characterized by a flat and unchanging pattern and three showing a small but statistically significant decrease over time. Analysis of pain-related outcomes predicted by SPTS-12 trajectories provided evidence of criterion validity of the SPTS-12. SPTS-12 trajectories did not significantly differ on daily MME at any time. Average pain, pain interference, and depression scores significantly differed across SPTS-12 trajectory groups at two or more postsurgical visits (all p < 0.05).

Conclusion

The SPTS-12 shows fairly stable patterns and predicts important pain-related and psychosocial outcomes over time. Two SPTS-12 trajectories (#2 and #5) with high scores, comprising ~28% of the total sample, are associated with problematic outcomes on several pain and psychosocial measures. Targeting patients with high SPTS-12 scores for presurgical psychological treatment may prove beneficial in reducing the impact of CPSP.

A systematic literature review and narrative synthesis on the risk factors for developing affective disorders in open lower-limb fracture patients

Background

Despite the advancements made in the management of the physical complications of open lower-limb fractures, few studies have been performed which investigate the association of such injuries with affective disorders. The complications resulting from this injury may result in significant psychological distress.

Aim

To evaluate the risk factors associated with the development of affective disorders, in patients with open lower-limb fractures.

Methods

A systematic review protocol was registered with PROSPERO and reported in accordance with the Preferred Reporting for Items for Systematic Reviews and Meta-Analyses. A comprehensive literature search was performed to gather relevant papers. Two independent reviewers screened titles and abstracts according to the inclusion and exclusion criteria.

Results

2488 were screened according to the inclusion and exclusion criteria resulting in seven articles eligible for inclusion. Of the seven articles, two assessed for PTSD, one assessed for depression and PTSD concurrently, two assessed for anxiety and depression concurrently, and two assessed for psychological distress. With the exception of two studies, open lower limb fracture patients were included with other lower-limb injuries in their analysis. Furthermore, not all variables were available in all included studies. Risk factors identified included post-operative pain, mechanism and severity of injury, age of patient, social support and social deprivation.

Conclusions

Further studies are required within this area. However, addressing risk factors such as pain management, poor social support and inappropriate coping mechanisms, may reduce the incidence of affective disorders by equipping patients with necessary psychosocial resources.

•

Patients with strong social support have, in general, a lower risk of depression and psychological distress.

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Poverty is a risk factor in general for psychological distress.

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Negative affect may play an important role in determining physical function during the recovery period.

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In most patients, symptoms of psychological distress improve over time.

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Not all patients may display symptoms of psychological distress immediately post-injury.

Prevalence and Predictors of Chronic Pain with Two-Year Follow-Up After Knee Arthroplasty

Background

Pain relief is the most important issue in the long-term outcome of arthroplasty surgery, with nearly one-third of patients still suffered persistent pain and caused dissatisfaction after the surgery.

Methods

A total of 713 patients underwent primary elective primary TKA and UKA were included consecutively between July 2018 and December 2019, using binary logistic method to analyze the data.

Results

The prevalence of CPSP at rest and on movement at 2-year was 12.1% and 37.7% respectively after primary knee arthroplasty and CPSP at rest factors included: age above 80 (odds ratio [OR]= 6.72, 95% confidence interval [CI] 1.58 to 28.56), BMI above 30 (2.339, 1.02 to 5.383), and moderate to severe pain variables: preoperative pain, (1.95, 1.11 to 3.41); APSP on movement, 4.9 (2.31–10.6); and follow-up contralateral knee pain-at-rest scores (12.6, 5.5 to 28.5). Factors associated with presence of CPSP on movement included: no smoking (2.59, 1.07 to 6.26); and moderate to severe pain variables: preoperative pain, (1.57, 1.073 to 2.30); APSP at rest, (1.85, 1.13 to 3.02); APSP on movement, 6.11 (3.82 to 9.78); and follow-up contralateral knee pain-on-movement scores, 3.22 (2.08 to 5.00). Factors to occurrence of moderate to severe CPSP on movement include: presence of COPD (12.20, 2.19 to 67.98); and moderate to severe pain variables: preoperative pain (2.36, 1.32 to 4.23); APSP on movement (4.68, 1.95 to 11.25); and follow-up contralateral knee pain-on-movement scores (2.71, 1.66 to 4.42).

Conclusion

Prevention strategies should be targeted to different types of pain, and the comorbidity of COPD undergoing knee arthroplasty should receive early identification and attention.

Presurgical distress about bodily sensations predicts chronic postsurgical pain intensity and disability 6 months after cardiothoracic surgery

ABSTRACT

Chronic postsurgical pain (CPSP) and disability after cardiothoracic surgery are highly prevalent and difficult to treat. Researchers have explored a variety of presurgical risk factors for CPSP and disability after cardiothoracic surgery, including one study that examined distress from bodily sensations. The current prospective, longitudinal study sought to extend previous research by investigating presurgical distress about bodily sensations as a risk factor for CPSP and disability after cardiothoracic surgery while controlling for several other potential psychosocial predictors. Participants included 543 adults undergoing nonemergency cardiac or thoracic surgery who were followed over 6 months postsurgically. Before surgery, participants completed demographic, clinical, and psychological questionnaires. Six months after surgery, participants reported the intensity of CPSP on a 0 to 10 numeric rating scale and pain disability, measured by the Pain Disability Index. Multinomial logistic regression analyses were conducted to evaluate the degree to which presurgical measures predicted pain outcomes 6 months after surgery. The results showed that CPSP intensity was significantly predicted by age and presurgical scores on the Symptom Checklist-90-Revised Somatization subscale (Nagelkerke R2 = 0.27, P < 0.001), whereas chronic pain disability was only predicted by presurgical Symptom Checklist-90-Revised Somatization scores (Nagelkerke R2 = 0.29, P < 0.001). These findings demonstrate that presurgical distress over bodily sensations predicts greater chronic pain intensity and disability 6 months after cardiothoracic surgery and suggest that presurgical treatment to diminish such distress may prevent or minimize CPSP intensity and disability.

An Examination of Chronic Pain Indices and the Updated Posttraumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental-Disorders-Fifth Edition

INTRODUCTION

Chronic pain and post-traumatic stress disorder (PTSD) comorbidity is prevalent among veterans and is associated with increased levels of pain severity and pain-related disability. An improved understanding of the relationship between these co-occurring disorders, in addition to effective integrated treatments, will develop by considering the changes to the PTSD diagnostic criteria in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). The current study examined the relationship between the revised PTSD Checklist for DSM-5 (PCL-5) symptom clusters (i.e., intrusion, avoidance, negative alterations in cognition and mood [NACM], and arousal) and chronic pain measurements (i.e., pain severity, interference, and disability).

MATERIALS AND METHODS

Participants included 103 veterans (ages 26-70, mean = 45.33) participating in a randomized clinical trial examining the efficacy of an interdisciplinary pain management program for chronic musculoskeletal pain. The study was approved by a university system Institutional Review Board and affiliated healthcare system.

RESULTS

The participants with a provisional PTSD diagnosis based on PCL-5 responses (N = 76) had significantly greater pain severity, interference, and disability than the participants without a provisional diagnosis (N = 23). Correlations between symptom clusters and pain measurements were mostly significant and positive with varying strengths. The avoidance symptom cluster, however, had relatively weaker correlations with pain measurements and was not significantly associated with the numeric rating scale of pain severity. Path analyses revealed that, after controlling for avoidance symptoms, significant associations remained between NACM and all the pain measurements. After controlling for NACM symptoms, however, there were no significant associations between avoidance symptoms and pain measurements.

CONCLUSION

The current study highlights a need to re-examine the leading theories about the mutual maintenance of these disorders in order to develop effective integrative treatment approaches. PTSD-related avoidance may have a relatively weaker role in co-occurring chronic pain than the other symptom clusters and may have a qualitatively different role than chronic pain-related avoidance. Future research should explore the relationship between the avoidance in PTSD and the avoidance in chronic pain as well as identify which chronic pain measurements are the most useful when examining the relationship between PTSD and chronic pain. The potential impact of trauma-related cognition and mood on chronic pain indicates that this is an important area for intervention and should be considered in the development of integrated treatments for chronic pain and PTSD among veterans.

Predictors of one year chronic post-surgical pain trajectories following thoracic surgery

PURPOSE

Chronic post-surgical pain (CPSP) is a highly prevalent complication following thoracic surgery. This is a prospective cohort study that aims to describe the pain trajectories of patients undergoing thoracic surgery beginning preoperatively and up to 1 year after surgery METHODS: Two hundred and seventy nine patients undergoing elective thoracic surgery were enrolled. Participants filled out a preoperative questionnaire containing questions about their sociodemographic information, comorbidities as well as several psychological and pain-related statuses. They were then followed-up during their immediate postoperative period and at the three, six and 12 month time-points to track their postoperative pain, complications and pain-related outcomes. Growth mixture modeling was used to construct pain trajectories.

RESULTS

The first trajectory is characterized by 185 patients (78.1%) with mild pain intensity across the 12 month period. The second is characterized by 32 patients (7.5%) with moderate pain intensity immediately after surgery which decreases markedly by 3 months and remains low at the 12 month follow-up. The final trajectory is characterized by 20 patients (8.4%) with moderate pain intensity immediately after surgery which persists at 12 months. Patients with moderate to severe postoperative pain intensity were much more likely to develop CPSP compared to patients with mild pain intensity. Initial pain intensity levels immediately following surgery as well as levels of pain catastrophizing at baseline were predicting pain trajectory membership. None of the surgical or anesthetic-related variables were significantly associated with pain trajectory membership.

CONCLUSION

Patients who undergo thoracic surgery can have postoperative pain that follows one of the three different types of trajectories. Higher levels of immediate postoperative pain and preoperative pain catastrophizing were associated with moderately severe CPSP.

Toward Understanding Movement-evoked Pain (MEP) and its Measurement: A Scoping Review

OBJECTIVE

Individuals with chronic pain conditions often report movement as exacerbating pain. An increasing number of researchers and clinicians have recognized the importance of measuring and distinguishing between movement-evoked pain (MEP) and pain at rest as an outcome. This scoping review maps the literature and describes MEP measurement techniques.

MATERIALS AND METHODS

The scoping review utilized 6 databases to identify original studies that targeted pain or movement-related outcomes. Our search returned 7322 articles that were screened by title and abstract by 2 reviewers. The inclusion criteria focused on the measurement of MEP before, during, and after movement tasks in adults with chronic pain. Studies of children below 18 years of age or with nonhuman animals, case studies, qualitative studies, book chapters, cancer-related pain, non-English language, and abstracts with no full publish text were excluded from the study.

RESULTS

Results from 38 studies revealed great variation in the measurement of MEP, while almost all of the studies did not provide an explicit conceptual or operational definition for MEP. In addition, studies collectively illuminated differences in MEP compared with rest pain, movement provocation methods, and pain intensity as the primary outcome.

DISCUSSION

These results have clinically significant and research implications. To advance the study of MEP, we offer that consistent terminology, standardized measurement (appropriate for pain type/population), and clear methodological processes be provided in research publications. On the basis of the findings, we have put forth a preliminary definition of MEP that may benefit from the continued scholarly dialog.

Chronic postsurgical pain: From risk factor identification to multidisciplinary management at the Toronto General Hospital Transitional Pain Service

Background: Chronic postsurgical pain is a highly prevalent public health problem associated with substantial emotional, social, and economic costs. Aims: (1) To review the major risk factors for chronic postsurgical pain (CPSP); (2) to describe the implementation of the Transitional Pain Service (TPS) at the Toronto General Hospital, a multiprofessional, multimodal preventive approach to CPSP involving intensive, perioperative psychological, physical, and pharmacological management aimed at preventing and treating the factors that increase the risk of CPSP and related disability; and (3) to present recent empirical evidence for the efficacy of the TPS. Methods: The Toronto General Hospital TPS was specifically developed to target patients at high risk of developing CPSP. The major known risk factors for CPSP are perioperative pain, opioid use, and negative affect, including depression, anxiety, pain catastrophizing, and posttraumatic stress disorder-like symptoms. At-risk patients are identified early and provided comprehensive care by a multidisciplinary team consisting of pain physicians, advanced practice nurses, psychologists, and physical therapists. Results: Preliminary results from two nonrandomized, clinical practice-based trials indicate that TPS treatment is associated with improvements in pain, pain interference, pain catastrophizing, symptoms of anxiety and depression, and opioid use. Almost half of opioid-naïve patients and one in four opioid-experienced patients were opioid free by the 6-month point. Conclusions: These promising results suggest that the TPS benefits patients at risk of CPSP. A multicenter randomized controlled trial of the TPS in several Ontario hospitals is currently underway.

Toward a phenomic analysis of chronic postsurgical pain following cardiac surgery

Background: Despite the same surgical approach, up to 40% of patients develop chronic postsurgical pain (CPSP) following cardiac surgery, whereas the rest are chronic pain free. This variability suggests that CPSP is controlled partially through genetics, but the genes for CPSP are largely unknown.

Aims: The aim of this study was to identify potential CPSP phenotypes by comparing patients who developed CPSP following cardiac surgery vs. those who did not.

Methods: A research ethics board–approved, cross-sectional study of post–cardiac surgery pain was conducted at Toronto General Hospital from 2011 to 2015. Patients were recruited to complete a short survey of chronic pain scores and the Short-Form McGill Pain Questionnaire–2. A subset of patients completed a longer survey of eight validated pain phenotyping questionnaires and/or four psychophysical assessments. All surveys and psychophysical testing were conducted after surgery. Patients were stratified by presence of chronic pain and groups were compared using descriptive statistics.

Results: Six hundred forty-three patients completed the short form survey. The mean postsurgery assessment time was 41.5 (SD = ±25.1) months. Over a quarter (27.8%) reported CPSP at the chest as a consequence of their surgery. Of patients reporting CPSP, 46.6% reported mild pain (0–3), 35.8% reported moderate pain (4–7), and 17.6% reported severe pain (7–10) in accordance with the numerical rating scale. Patients with moderate and/or severe CPSP were younger, had a greater body mass index, and had higher anxiety sensitivity, pain catastrophizing, and somatization scores.

Conclusions: Chronic pain levels after cardiac surgery are associated with anxiety, catastrophizing, and sensory abnormalities in body parts outside the field innervated by injured nerves, indicating the presence of widespread central sensitization to incoming sensory inputs from intact nerves.

Do post-traumatic pain and post-traumatic stress symptomatology mutually maintain each other? A systematic review of cross-lagged studies

After traumatic exposure, individuals are at risk of developing symptoms of both pain and post-traumatic stress disorder (PTSD). Theory and research suggest a complex and potentially mutually maintaining relationship between these symptomatologies. However, findings are inconsistent and the applied methods are not always well suited for testing mutual maintenance. Cross-lagged designs can provide valuable insights into such temporal associations, but there is a need for a systematic review to assist clinicians and researchers in understanding the nature of the relationship. Thus, the aim of this systematic review was to identify, critically appraise, and synthesize results from cross-lagged studies on pain and PTSD symptomatology to assess the evidence for longitudinal reciprocity and potential mediators. Systematic searches resulted in 7 eligible studies that were deemed of acceptable quality with moderate risk of bias using the cohort study checklist from Scottish Intercollegiate Guidelines Network. Furthermore, synthesis of significant pathways in the cross-lagged models showed inconsistent evidence of both bidirectional and unidirectional interaction patterns between pain and PTSD symptomatology across time, hence not uniformly supporting the theoretical framework of mutual maintenance. In addition, the synthesis suggested that hyperarousal and intrusion symptoms may be of particular importance in these cross-lagged relationships, while there was inconclusive evidence of catastrophizing as a mediator. In conclusion, the findings suggest an entangled, but not necessarily mutually maintaining relationship between pain and PTSD symptomatology. However, major variations in findings and methodologies complicated synthesis, prompting careful interpretation and heightening the likelihood that future high-quality studies will change these conclusions.

Number and Type of Post-Traumatic Stress Disorder Symptom Domains Are Associated With Patient-Reported Outcomes in Patients With Chronic Pain

Post-traumatic stress disorder (PTSD) commonly accompanies complex chronic pain, yet PTSD is often overlooked in chronic pain management. Using the 4-item Primary Care (PC)-PTSD screening tool, we evaluated the relationship between the number and type of PC-PTSD symptoms endorsed and a set of patient-reported outcomes, including: pain intensity and interference, function, mood, quality of life, and substance abuse risk in a consecutive sample of patients with chronic pain (n = 4,402). Patients completed PainTracker, a Web-based patient-reported outcome tool that provides a multidimensional evaluation of chronic pain, as part of their intake evaluation at a specialty pain clinic in a community setting. Twenty-seven percent of the sample met PC-PTSD screening criteria for PTSD by endorsing 3 of the 4 symptom domains. Significant ordinal trends were observed between increasing number of PTSD symptoms and all outcomes evaluated. The occurrence of even 1 PTSD symptom was associated with overall poorer outcomes, suggesting that subsyndromal PTSD is clinically significant in the context of chronic pain. Among the 4 PTSD domains assessed, "numbness/detachment" was most strongly associated with negative pain outcomes in relative weight analysis. Results from this cross-sectional study suggest that a range of pain-related outcomes may be significantly related to comorbid PTSD.

PERSPECTIVE

We present evidence that PTSD symptoms are significantly related to a broad set of pain-related patient-reported outcomes. These findings highlight the need to evaluate for PTSD symptoms in patients with chronic pain, especially feelings of numbness or detachment from others, to improve understanding and management of chronic pain.

The psychology of chronic post-surgical pain: new frontiers in risk factor identification, prevention and management

In an era of considerable advances in anaesthesiology and pain medicine, chronic pain after major surgery continues to be problematic. This article briefly reviews the known psychological risk and protective factors associated with the development of chronic postsurgical pain (CPSP). We begin with a definition of CPSP and then explain what we mean by a risk/protective factor. Next, we summarize known psychological risk and protective factors for CPSP. Psychological interventions that target risk factors and may impact postsurgical pain are reviewed, including the acceptance and commitment therapy (ACT)-based approach to CPSP prevention and management we use in the Transitional Pain Service (TPS) at the Toronto General Hospital. Finally, we conclude with recommendations for research in risk factor identification and psychological interventions to prevent CPSP. Several pre-surgical psychological risk factors for CPSP have been consistently identified in recent years. These include negative affective constructs, such as anxiety symptoms, depressive symptoms, pain catastrophizing and general psychological distress. In contrast, relatively few studies have examined psychological protective factors for CPSP. Psychological interventions that target known psychological risk factors while enhancing protective psychological factors may reduce new incidence of CPSP. The primary goal of our ACT intervention is to teach patients a mindful way of responding to their postsurgical pain that empowers them to interrupt the negative cycle of pain, distress, behavioural avoidance and escalating opioid use that can limit functioning and quality of life while paradoxically amplifying pain over time. Early clinical outcome data suggest that patients who receive care from TPS physicians reduce their pain and opioid use, yet patients who also receive our ACT intervention have a larger decrease in daily opioid dose while reporting less pain interference and lower depression scores.

Sensitivity to Pain Traumatization Scale: development, validation, and preliminary findings

Background

This article reports three studies describing the development and validation of the 12-item Sensitivity to Pain Traumatization Scale (SPTS-12). SPT refers to the anxiety-related cognitive, emotional, and behavioral reactions to pain that resemble the features of a traumatic stress reaction.

Methods

In Study 1, a preliminary set of 79 items was administered to 116 participants. The data were analyzed by using combined nonparametric and parametric item response theory resulting in a 12-item scale with a one-factor structure and good preliminary psychometric properties. Studies 2 and 3 assessed the factor structure and psychometric properties of the SPTS-12 in a community sample of 823 participants (268 with chronic pain and 555 pain-free) and a clinical sample of 345 patients (126 with chronic post-surgical pain, 92 with other nonsurgical chronic pain, and 127 with no chronic pain) at least 6 months after undergoing coronary artery bypass graft surgery, respectively.

Results

The final SPTS-12 derived from Study 1 comprised 12 items that discriminated between individuals with different levels of SPT, with the overall scale showing good to very good reliability and validity. The results from Studies 2 and 3 revealed a one-factor structure for chronic pain and pain-free samples, excellent reliability and concurrent validity, and moderate convergent and discriminant validity.

Conclusion

The results of the three studies provide preliminary evidence for the validity and reliability of the SPTS-12.

A Prospective Study of Chronic Pain after Thoracic Surgery

BACKGROUND

The goal of this study was to detect the predictors of chronic pain at 6 months after thoracic surgery from a comprehensive evaluation of demographic, psychosocial, and surgical factors.

METHODS

Thoracic surgery patients were enrolled 1 week before surgery and followed up 6 months postsurgery in this prospective, observational study. Comprehensive psychosocial measurements were assessed before surgery. The presence and severity of pain were assessed at 3 and 6 months after surgery. One hundred seven patients were assessed during the first 3 days after surgery, and 99 (30 thoracotomy and 69 video-assisted thoracoscopic surgery, thoracoscopy) patients completed the 6-month follow-up. Patients with versus without chronic pain related to thoracic surgery at 6 months were compared.

RESULTS

Both incidence (P = 0.37) and severity (P = 0.97) of surgery-related chronic pain at 6 months were similar after thoracotomy (33%; 95% CI, 17 to 53%; 3.3 ± 2.1) and thoracoscopy (25%; 95% CI, 15 to 36%; 3.3 ± 1.7). Both frequentist and Bayesian multivariate models revealed that the severity of acute pain (numerical rating scale, 0 to 10) is the measure associated with chronic pain related to thoracic surgery. Psychosocial factors and quantitative sensory testing were not predictive.

CONCLUSIONS

There was no difference in the incidence and severity of chronic pain at 6 months in patients undergoing thoracotomy versus thoracoscopy. Unlike other postsurgical pain conditions, none of the preoperative psychosocial measurements were associated with chronic pain after thoracic surgery.

Persistent postsurgical pain after video-assisted thoracic surgery--an observational study

BACKGROUND

The risk of persistent postsurgical pain (PPP) and subsequent pain-related functional impairment may potentially be reduced by video-assisted thoracic surgery (VATS) compared to thoracotomy. The aim of the study was therefore to assess in detail the incidence and consequences on activities of daily living of PPP after VATS.

METHODS

Using a prospective observational design, 47 patients undergoing VATS completed both preoperative, early postoperative and 3 months follow-up. Preoperative pain, pain characteristics, psychological factors, pain-related functional impairment and quantitative sensory testing (QST) including nociceptive thresholds were compared with postoperative data.

RESULTS

Only five (11%) patients developed PPP with NRS > 3 originating from the surgical area. However, about 30% of patients still reported some pain-related functional impairment from the surgical area within four well-defined domains of everyday activities. Psychological and sensory thermal tests did not predict persistent postoperative pain, except preoperative pin-prick sensitivity was higher in patients with PPP. Postoperative pain 7 days after surgery was significantly higher in PPP patients. Preoperative pain originating from remote areas did not predict PPP.

CONCLUSION

The incidence of PPP, nerve damage (based on QST) and pain-related functional impairment following VATS was lower than reported following thoracotomy. No psychological or other factors predicted PPP. These findings call for further large-scale studies to support VATS to decrease PPP.

Comparing the Prevalence, Risk Factors, and Repercussions of Postpartum Genito-Pelvic Pain and Dyspareunia

INTRODUCTION

Childbirth is a risk factor for developing genito-pelvic pain and/or dyspareunia during the postpartum period and potentially in the longer term. These two types of pain can occur simultaneously or sequentially and could be affected by different risk factors and have a range of repercussions to women's lives, including their sexual functioning.

AIM

This study reviewed the available evidence to compare and contrast the prevalence, risk factors, and repercussions of postpartum genito-pelvic pain vs dyspareunia.

METHODS

All available data related to postpartum genito-pelvic pain and dyspareunia were reviewed.

MAIN OUTCOME MEASURES

A description of the prevalence, risk factors, and sexual and psychological consequences of postpartum genito-pelvic pain and dyspareunia and the methodologic limitations of previous studies.

RESULTS

The prevalence of postpartum genito-pelvic pain is much lower than that of postpartum dyspareunia. There is evidence of converging and differential risk factors for acute and persistent experiences of these two types of pain. Postpartum genito-pelvic pain and dyspareunia are associated with impaired sexual functioning. Rarely are these pain experiences examined together to make direct comparisons.

CONCLUSION

There has been a critical lack of studies examining postpartum genito-pelvic pain and dyspareunia together and integrating biomedical and psychosocial risk factors. This approach should be spearheaded by a multidisciplinary group of researchers of diverse and relevant expertise, including obstetricians, gynecologists, anesthesiologists, and psychologists.

Preventive analgesia and novel strategies for the prevention of chronic post-surgical pain

Chronic post-surgical pain (CPSP) is a serious complication of major surgery that can impair a patient's quality of life. The development of CPSP is a complex process which involves biologic, psychosocial, and environmental mechanisms that have yet to be fully understood. Currently perioperative pharmacologic interventions aim to suppress and prevent sensitization with the aim of reducing pain and analgesic requirement in acute as well as long-term pain . Despite the detrimental effects of CPSP on patients, the body of literature focused on treatment strategies to reduce CPSP remains limited and continues to be understudied. This article reviews the main pharmacologic candidates for the treatment of CPSP, discusses the future of preventive analgesia, and considers novel strategies to help treat acute post-operative pain and lessen the risk that it becomes chronic. In addition, this article highlights important areas of focus for clinical practice including: multimodal management of CPSP patients, psychological modifiers of the pain experience, and the development of a Transitional Pain Service specifically designed to manage patients at high risk of developing chronic post-surgical pain.

The Toronto General Hospital Transitional Pain Service: development and implementation of a multidisciplinary program to prevent chronic postsurgical pain

Chronic postsurgical pain (CPSP), an often unanticipated result of necessary and even life-saving procedures, develops in 5-10% of patients one-year after major surgery. Substantial advances have been made in identifying patients at elevated risk of developing CPSP based on perioperative pain, opioid use, and negative affect, including depression, anxiety, pain catastrophizing, and posttraumatic stress disorder-like symptoms. The Transitional Pain Service (TPS) at Toronto General Hospital (TGH) is the first to comprehensively address the problem of CPSP at three stages: 1) preoperatively, 2) postoperatively in hospital, and 3) postoperatively in an outpatient setting for up to 6 months after surgery. Patients at high risk for CPSP are identified early and offered coordinated and comprehensive care by the multidisciplinary team consisting of pain physicians, advanced practice nurses, psychologists, and physiotherapists. Access to expert intervention through the Transitional Pain Service bypasses typically long wait times for surgical patients to be referred and seen in chronic pain clinics. This affords the opportunity to impact patients' pain trajectories, preventing the transition from acute to chronic pain, and reducing suffering, disability, and health care costs. In this report, we describe the workings of the Transitional Pain Service at Toronto General Hospital, including the clinical algorithm used to identify patients, and clinical services offered to patients as they transition through the stages of surgical recovery. We describe the role of the psychological treatment, which draws on innovations in Acceptance and Commitment Therapy that allow for brief and effective behavioral interventions to be applied transdiagnostically and preventatively. Finally, we describe our vision for future growth.

The role of experiential avoidance, resilience and pain acceptance in the adjustment of chronic back pain patients who have experienced a traumatic event: a path analysis

BACKGROUND

The degree to which shared vulnerability and protective factors for chronic pain and trauma-related symptoms contribute to pain adjustment in chronic pain patients who have experienced a traumatic event remains unclear.

PURPOSE

The purpose is to test a hypothetical model of the contribution of experiential avoidance, resilience and pain acceptance to pain adjustment in a sample of 229 chronic back pain patients who experienced a traumatic event before the onset of pain.

METHODS

Structural equation modelling was used to test the linear relationships between the variables.

RESULTS

The empirical model shows significant relationships between the variables: resilience on pain acceptance and trauma-related symptoms, experiential avoidance on trauma-related symptoms and experiential avoidance, pain acceptance and trauma-related symptoms on pain adjustment.

CONCLUSIONS

This study demonstrates the role of a vulnerability pathway (i.e. experiential avoidance) and a protective pathway (i.e. resilience and pain acceptance) in adaptation to pain after a traumatic event.

The temporal relationship between mental health and disability after injury

OBJECTIVE

This longitudinal study investigated the temporal relationship patterns between disability and mental health after injury, with a focus on posttraumatic stress disorder (PTSD), depression, and anxiety.

METHOD

We conducted a multi-sited longitudinal cohort study with a large sample of hospital patients admitted after injury (N = 1,149, mean age = 37.9, 73.6% male). Data were collected prior to discharge from hospital, and follow-up assessments took place 3 and 12 months postinjury. A cross-lagged structural equation model (SEM) was used to assess the prospective relationship between posttraumatic stress, anxiety, and depression symptoms and disability while controlling for demographic characteristics and objective measures of injury severity.

RESULTS

Acute depression significantly predicted 3-month disability, and 3-month PTSD severity significantly predicted 12-month disability. Premorbid disability had a significant effect on acute anxiety, depression, and posttraumatic stress symptoms, and 3-month depression but disability after the injury did not predict 12-month psychopathology.

CONCLUSIONS

We did not find a reciprocal relationship between disability and psychopathology. Rather we found that depression played a role in early disability while PTSD played a role in contributing to long-term delays in the recovery process. The results of this study highlight the need for mental health screening for symptoms of PTSD and depression in the acute aftermath of trauma, combined with early intervention programs in injury populations.

Incidence and severity of chronic pain at 3 and 6 months after thoracotomy: meta-analysis

This systematic review was performed to determine the incidence and the severity of chronic pain at 3 and 6 months after thoracotomy based on meta-analyses. We conducted MEDLINE, Web of Science, and Google Scholar searches of databases and references for English articles; 858 articles were reviewed. Meta-regression analysis based on the publication year was used to examine if the chronic pain rates changed over time. Event rates and confidence intervals with random effect models and Freeman-Tukey double arcsine variance-stabilizing transformation were obtained separately for the incidence of chronic pain based on 1,439 patients from 17 studies at 3 months and 1,354 patients from 15 studies at 6 months. The incidences of chronic pain at 3 and 6 months after thoracotomy were 57% (95% confidence interval [CI], 51-64%) and 47% (95% CI, 39-56%), respectively. The average severity of pain ratings on a 0 to 100 scale at these times were 30 ± 2 (95% CI, 26-35) and 32 ± 7 (95% CI, 17-46), respectively. Reported chronic pain rates have been largely stable at both 3 and 6 months from the 1990s to the present.

PERSPECTIVE

This systematic review's findings suggest that reported chronic pain rates are approximately 50% at 3 and 6 months and have been largely stable from the 1990s to the present. The severity of this pain is not consistently reported. Chronic pain after thoracotomy continues to be a significant problem despite advancing perioperative care.

An examination of the structural link between post-traumatic stress symptoms and chronic pain in the framework of fear-avoidance models

BACKGROUND

The tendency to respond with fear and avoidance can be seen as a shared vulnerability contributing to the development of post-traumatic stress disorder (PTSD) and chronic pain. Although several studies have examined which specific symptoms of PTSD (re-experiencing, avoidance, emotional numbing and hyperarousal) are associated with chronic pain, none has considered this association within the framework of fear-avoidance models.

METHODS

Seven hundred fourteen patients with chronic musculoskeletal pain were assessed. Of these, 149 patients were selected for the study based upon the following inclusion criteria: exposure to a traumatic event before the onset of pain (with scores equal to or higher than 8 points on the fear and hopelessness scales of the Stressful Life Event Screening Questionnaire Revised) and scores equal to or higher than 30 on the Davidson Trauma Scale.

RESULTS

Structural equation modelling was used to test the association between PTSD symptoms and pain outcomes (pain intensity and disability) using the mediating variables considered in the fear-avoidance models. The results show that emotional numbing and hyperarousal symptoms, but neither re-experiencing nor avoidance, affected pain outcome via anxiety sensitivity (AS), catastrophizing and fear of pain. PTSD symptoms increased the levels of AS, which predisposes to catastrophizing and, in turn, had an effect on the tendency of pain patients to respond with more fear and avoidance.

CONCLUSIONS

This study provides empirical support for the potential role of PTSD symptoms in fear-avoidance models of chronic pain and suggests that AS is a relevant variable in the relationship between both disorders.

Neuropathic aspects of persistent postsurgical pain: a French multicenter survey with a 6-month prospective follow-up

To investigate the role of peripheral neuropathy in the development of neuropathic postsurgical persistent pain (N-PSPP) after surgery, this French multicentric prospective cohort study recruited 3,112 patients prior to elective cesarean, inguinal herniorrhaphy (open mesh/laparoscopic), breast cancer surgery, cholecystectomy, saphenectomy, sternotomy, thoracotomy, or knee arthroscopy. Besides perioperative data collection, postoperative postal questionnaires built to assess the existence, intensity, and neuropathic features (with the Douleur Neuropathique 4 Questions [DN4]) of pain at the site of surgery were sent at the third and sixth months after surgery. In the 2,397 patients who completed follow-up, the cumulative risk of N-PSPP within the 6 months ranged from 3.2% (laparoscopic herniorrhaphy) to 37.1% (breast cancer surgery). Pain intensity was greater if DN4 was positive and decreased with time since surgery; it depended on the type of surgery. In pain-reporting patients, the response to the DN4 changed from time to time in about 1:4 of the cases. Older age and a low anxiety score were independent protective factors of N-PSPP, whereas a recent negative event, a low preoperative quality of life, and previous history of peripheral neuropathy were risk factors. The type of anesthesia had no influence on the occurrence of N-PSPP.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00812734.

PERSPECTIVE

This prospective observational study provides the incidence rate of N-PSPP occurring within the 6 months after 9 types of elective surgical procedures. It highlights the possible consequences of nerve aggression during some common surgeries. Finally, some preoperative predispositions to the development of N-PSPP have been identified.

The Qualitative Hyperalgesia Profile: A New Metric to Assess Chronic Post-Thoracotomy Pain

Thoracotomy often results in chronic pain, characterized by resting pain and elevated mechano-sensitivity. This paper defines complex behavioral responses to tactile stimulation in rats after thoracotomy, shown to be reversibly relieved by systemic morphine, in order to develop a novel qualitative "pain" score. A deep incision and 1 hour of rib retraction in male Sprague-Dawley rats resulted in reduced threshold and a change in the locus of greatest tactile (von Frey filament) sensitivity, from the lower back to a more rostral location around the wound site, and extending bilaterally. The fraction of rats showing nocifensive responses to mild stimulation (10 gm) increased after thoracotomy (from a pre-operative value of 0/10 to 8/10 at 10 days post-op), and the average threshold decreased correspondingly, from 15 gm to ∼4 gm. The nature of the nocifensive responses to tactile stimulation, composed pre-operatively only of no response (Grade 0) or brief contractions of the local subcutaneous muscles (Grade I), changed markedly after thoracotomy, with the appearance of new behaviors including a brisk lateral "escape" movement and/or a 180° rotation of the trunk (both included as Grade II), and whole body shuddering, and scratching and squealing (Grade III). Systemic morphine (2.5 mg/kg, i.p.) transiently raised the threshold for response and reduced the frequency of Grade II and III responses, supporting the interpretation that these represent pain. The findings support the development of a Qualitative Hyperalgesic Profile to assess the complex behavior that indicates a central integration of hyperalgesia.

Are psychological predictors of chronic postsurgical pain dependent on the surgical model? A comparison of total knee arthroplasty and breast surgery for cancer

Anxiety, depression, and catastrophizing are generally considered to be predictive of chronic postoperative pain, but this may not be the case after all types of surgery, raising the possibility that the results depend on the surgical model. We assessed the predictive value of these factors for chronic postsurgical pain in 2 different surgical models: total knee arthroplasty for osteoarthritis (89 patients, 65% women, age = 69 ± 9 years, baseline pain intensity = 4.7 ± 2.1) and breast surgery for cancer (100 patients, 100% women, age = 55 ± 12 years, no preoperative pain). Data were collected before surgery, then 2 days and 3 months after surgery. Anxiety, depression, and catastrophizing were measured with the Spielberger State-Trait Anxiety Inventory, Beck Depression Inventory, and Pain Catastrophizing Scale, respectively. Pain was assessed with the Brief Pain Inventory. Neuropathic pain was detected with the DN4 questionnaire. Multivariate logistic regression analyses for the total knee arthroplasty and breast surgery models considered together indicated that the presence of clinically meaningful chronic pain at 3 months (pain intensity ≥3/10) was predicted independently by age (P = .04), pain intensity on day 2 (P = .009), and state anxiety (P = .001). Linear regression models also showed that pain magnification, one of the dimensions of catastrophizing, independently predicted chronic pain intensity (P = .04). These results were not affected by the surgical model or by the neuropathic characteristics of the pain. Thus, state anxiety and pain magnification seem to constitute psychological risk factors for chronic postsurgical pain relevant in all surgical models.

PERSPECTIVE

This prospective study performed in patients with total knee arthroplasty or breast surgery for cancer shows that state anxiety, amplification of pain, and acute postoperative pain independently predict postsurgical pain at 3 months and that this does not depend on the surgical model.

Identification of pain-related psychological risk factors for the development and maintenance of pediatric chronic postsurgical pain

Background

The goals of this study were to examine the trajectory of pediatric chronic postsurgical pain (CPSP) over the first year after surgery and to identify acute postsurgical predictors of CPSP.

Methods

Eighty-three children aged 8–18 years (mean 13.8, standard deviation 2.4) who underwent major orthopedic or general surgery completed pain and pain-related psychological measures at 48–72 hours, 2 weeks (pain anxiety and pain measures only), and 6 and 12 months after surgery.

Results

Results showed that 1 year after surgery, 22% of children developed moderate to severe CPSP with minimal functional disability. Children who reported a Numeric Rating Scale pain-intensity score ≥ 3 out of 10 two weeks after discharge were more than three times as likely to develop moderate/severe CPSP at 6 months and more than twice as likely to develop moderate/severe CPSP at 12 months than those who reported a Numeric Rating Scale pain score < 3 (6-month relative risk 3.3, 95% confidence interval 1.2–9.0 and 12-month relative risk 2.5, 95% confidence interval 0.9–7.5). Pain unpleasantness predicted the transition from acute to moderate/severe CPSP, whereas anxiety sensitivity predicted the maintenance of moderate/severe CPSP from 6 to 12 months after surgery.

Conclusions

This study highlights the prevalence of pediatric CPSP and the role played by psychological variables in its development/maintenance. Risk factors that are associated with the development of CPSP are different from those that maintain it.

Chronic postsurgical pain: still a neglected topic?

Background

Surgical injury can frequently lead to chronic pain. Despite the obvious importance of this problem, the first publications on chronic pain after surgery as a general topic appeared only a decade ago. This study tests the hypothesis that chronic postsurgical pain was, and still is, represented insufficiently.

Methods

We analyzed the presentation of this topic in journal articles covered by PubMed and in surgical textbooks. The following signs of insufficient representation in journal articles were used: (1) the lack of journal editorials on chronic pain after surgery, (2) the lack of journal articles with titles clearly indicating that they are devoted to chronic postsurgical pain, and (3) the insufficient representation of chronic postsurgical pain in the top surgical journals.

Results

It was demonstrated that insufficient representation of this topic existed in 1981–2000, especially in surgical journals and textbooks. Interest in this topic began to increase, however, mostly regarding one specific surgery: herniorrhaphy. It is important that the change in the attitude toward chronic postsurgical pain spreads to other groups of surgeries.

Conclusion

Chronic postsurgical pain is still a neglected topic, except for pain after herniorrhaphy. The change in the attitude toward chronic postsurgical pain is the important first step in the approach to this problem.

Examining the role of positive and negative affect in recovery from spine surgery

Consistent evidence supports a significant association between lower positive affect and higher negative affect and increased pain and disability in adults with chronic pain. However, examining this relation in surgical populations has received little empirical consideration. The primary purpose of this study was to determine whether preoperative and postoperative positive and negative affect predict pain, disability, and functional status after spine surgery. A secondary objective was to assess the relation of depression to postoperative outcomes compared with positive and negative affect. Participants were 141 patients treated by spine surgery for lumbar or cervical degeneration. Data collection occurred at baseline and 6 weeks and 3 months postoperatively. Affect was measured with the Positive and Negative Affect Schedule. Multivariable mixed-model linear regression analyses found that preoperative variables were not predictive of postoperative pain, disability and functional status. However, multivariable postoperative analysis found that 6-week positive affect predicted functional status, and 6-week negative affect predicted pain interference and pain-related disability at 3 months following surgery. Postoperative depression demonstrated statistically significant and stronger associations with pain intensity, pain interference, and pain-related disability at 3-month follow-up, as compared with negative affect. Results suggest that positive affect and depression are important variables to target when seeking to improve postoperative outcomes in a spine surgery population. Recommendations include postoperative screening for positive affect and depression, and treating depression as well as focusing on rehabilitation strategies to bolster positive affect so as to improve functional outcomes after spine surgery.

Sensitivity to pain traumatization: a higher-order factor underlying pain-related anxiety, pain catastrophizing and anxiety sensitivity among patients scheduled for major surgery

BACKGROUND

The present article addresses two related developments in the psychology of pain, and integrates them into a coherent framework to better understand the relationship between pain and trauma. The first is an emerging conceptualization regarding the nature of the hierarchical organization of major pain-related anxiety constructs. The second is the theoretical rationale and empirical evidence linking pain and symptoms of post-traumatic stress disorder.

OBJECTIVES

To explore the underlying hierarchical factor structure of commonly used pain-related anxiety measures including the Pain Anxiety Symptoms Scale (PASS-20), the Pain Catastrophizing Scale (PCS), and the Anxiety Sensitivity Index (ASI); and to relate this structure to post-traumatic stress disorder in patients scheduled for major surgery.

METHODS

Measures were completed by 444 patients scheduled to undergo major surgery. Exploratory factor analysis and subsequent higherorder analysis using the Schmid-Leiman transformation were conducted to investigate the underlying factor structure of the ASI, the PCS and the PASS-20.

RESULTS

Twenty items from the ASI, the PASS-20 and the PCS loaded exclusively on one higher-order factor. The authors suggest the term 'sensitivity to pain traumatization' (SPT) for the underlying construct based in part on the strong, significant positive correlation between SPT scores and scores on the Post-traumatic Stress Disorder Checklist - Civilian Version. Finally, the total SPT score was significantly higher for patients with a history of pain than for those without a history of pain, both before surgery and one year after surgery. SPT describes the propensity to develop anxiety-related somatic, cognitive, emotional and behavioural responses to pain that resemble features of a traumatic stress reaction. Together, the results of the present study provide preliminary evidence for the construct validity of SPT.

The Transition from Acute to Chronic Post Surgical Pain

All chronic pain was once acute, but not all acute pain becomes chronic. The transition of acute postoperative pain to chronic post surgical pain is a complex and poorly understood developmental process. The manuscript describes the various factors associated with the transition from acute to chronic pain. The preoperative, intraoperative and postoperative surgical, psychosocial, socio-environmental and patient-related factors and the mechanisms involved are discussed and preventive (or limitation) strategies are suggested. In future, the increasing understanding of genetic factors and the transitional mechanisms involved may reveal important clues to predict which patients will go on to develop chronic pain. This may assist the development of appropriate interventions affecting not only the individual concerned, but also ultimately the community at large.

Strategies Aimed at Preventing Chronic Post-surgical Pain: Comprehensive Perioperative Pain Management after Total Joint Replacement Surgery

PURPOSE

Chronic post-surgical pain (CPSP) is a frequent outcome of musculoskeletal surgery. Physiotherapists often treat patients with pain before and after musculoskeletal surgery. The purposes of this paper are (1) to raise awareness of the nature, mechanisms, and significance of CPSP; and (2) to highlight the necessity for an inter-professional team to understand and address its complexity. Using total joint replacement surgeries as a model, we provide a review of pain mechanisms and pain management strategies.

SUMMARY OF KEY POINTS

By understanding the mechanisms by which pain alters the body's normal physiological responses to surgery, clinicians selectively target pain in post-surgical patients through the use of multi-modal management strategies. Clinicians should not assume that patients receiving multiple medications have a problem with pain. Rather, the modern-day approach is to manage pain using preventive strategies, with the aims of reducing the intensity of acute postoperative pain and minimizing the development of CPSP.

CONCLUSIONS

The roles of biological, surgical, psychosocial, and patient-related risk factors in the transition to pain chronicity require further investigation if we are to better understand their relationships with pain. Measuring pain intensity and analgesic use is not sufficient. Proper evaluation and management of risk factors for CPSP require inter-professional teams to characterize a patient's experience of postoperative pain and to examine pain arising during functional activities.

Psychological distress mediates the effect of pain on function

As part of a larger longitudinal study, the current analyses characterize the relationship among pain, psychological distress, and physical function after major lower extremity trauma. Structural equation modeling techniques were utilized to analyze data from a prospective 2-year observational study of 327 patients treated at 8 level I trauma centers. Data were gathered at 3, 6, 12, and 24 months after injury. In the models tested, higher levels of depressive and anxious distress at the preceding time point was related to lower levels of functioning at 6, 12, and 24 months, and higher levels of pain at the preceding time point were related to lower levels of functioning at 6 and 12 months, but not at 24 months. A reverse model in which lower levels of functioning led to higher levels of psychological distress or pain was tested and did not fit the data. The combination of depressive and anxious distress plays an increasingly important role in mediating the impact of pain on physical function as the recovery from lower extremity trauma progresses from early to later stages. Both pain and psychological distress contribute to reduced function during the first year after a serious injury; however, as recovery proceeds, the role of psychological distress in determining function increases. Longitudinal data on patients with severe leg trauma demonstrates that as recovery proceeds, psychological distress plays an increasingly important role in mediating the impact of pain on function.

Daily functioning in chronic pain: study of structural relations with posttraumatic stress disorder symptoms, pain intensity, and pain avoidance

BACKGROUND

This study aimed to evaluate processes from the mutual maintenance model in relation to daily functioning in patients with both chronic pain and a history of a traumatic experience. The mechanism illustrated the structural relations for daily functioning among pain intensity, hyperarousal, re-experiencing, trauma avoidance, and pain avoidance.

METHODS

Archival data (N = 214) was used for this study and data were analyzed for 142 chronic pain patients reporting a traumatic experience and seeking treatment at a tertiary pain clinic in Korea.

RESULTS

The results indicated that pain intensity, hyperarousal, and pain avoidance had significant direct effects on daily functioning. Also, pain intensity showed significant indirect effects on daily functioning through hyperarousal and pain avoidance; and hyperarousal through pain avoidance.

CONCLUSIONS

Results suggest a direct contribution of high levels of pain, hyperarousal symptoms of PTSD, and pain avoidance behaviors to reduced daily functioning. Also, elevated pain as reminders of the trauma may trigger high levels of hyperarousal symptoms of PTSD. Subsequently, avoidant coping strategies may be used to minimize pain so that the trauma would not be re-experienced, thus inhibiting the activation of hyperarousal symptoms of PTSD. However, prolonged use of such strategies may contribute to decline in daily functioning.

Acute pain after total hip arthroplasty does not predict the development of chronic postsurgical pain 6 months later

PURPOSE

Much remains unknown about the relationship between acute postoperative pain and the development of pathologic chronic postsurgical pain (CPSP). The purpose of this project was to identify the extent to which maximum pain scores on movement over the first two days after total hip arthroplasty predicted the presence of chronic pain 6 months later after controlling for potentially important covariates.

METHODS

The sample comprised 82 of 114 patients who participated in a double-blinded randomized controlled trial in which all patients received acetaminophen 1 g p.o., celecoxib 400 mg p.o., and dexamethasone 8 mg i.v., 1-2 h preoperatively. In addition, patients received gabapentin (GBP) 600 mg (G2) or placebo (G1 and G3) 2 h prior to surgery [G1: placebo/placebo (n = 38); G2: GBP/placebo (n = 38); G3: placebo/GBP (n = 38)]. In the PACU, patients received gabapentin 600 mg (G3) or placebo (G1 and G2). Follow-up data from the 82 patients who were contacted by telephone 6 months postsurgery were used for the current study.

RESULTS

Maximal movement-evoked pain intensity over the first two postoperative days (P = 0.38) failed to predict the presence of CPSP 6 months later after controlling for age (P = 0.09), treatment group (P = 0.91), and cumulative morphine consumption (P = 0.8) (multivariate logistic regression likelihood ratio test against the intercept only model P = 0.59).

CONCLUSION

Neither maximum movement-evoked acute pain, nor any other factor measured, predicted the presence of CPSP at 6 months. Further research is needed to identify risk factors for CPSP after total hip arthroplasty.

Adding gabapentin to a multimodal regimen does not reduce acute pain, opioid consumption or chronic pain after total hip arthroplasty

BACKGROUND

Gabapentin (GPN) is effective in reducing post-operative pain and opioid consumption, but its effects with regional anesthesia for total hip arthroplasty (THA) are not known. We designed this study to determine whether (1) gabapentin administration reduces pain and opioid use after THA using a multimodal analgesic regimen including spinal anesthesia; (2) pre-operative administration of gabapentin is more effective than post-operative administration.

METHODS

After REB approval and informed consent, 126 patients were enrolled in a double-blinded, randomized-controlled study. Patients received acetaminophen 1 g per os (p.o.), celecoxib 400 mg p.o. and dexamethasone 8 mg intravenously, 1-2 h pre-operatively. Patients were randomly assigned to one of three treatment groups (G1: Placebo/Placebo; G2: GPN/Placebo; G3: Placebo/GPN). Patients received gabapentin 600 mg (G2) or placebo (G1 and G3) 2 h before surgery. All patients had spinal anesthesia [15 mg (3cc) of 0.5% hypobaric bupivacaine with 10 microg of fentanyl]. In the post-anesthetic care unit, patients received gabapentin 600 mg (G3) or placebo (G1 and G2). On the ward, patients received acetaminophen 1000 mg p.o. q6h, celecoxib 200 mg p.o. q12h and a morphine PCA device. Patients were interviewed 6 months post-surgery to determine the incidence and severity of chronic post-surgical pain.

RESULTS

Mean+/-SD cumulative morphine (mg) consumption (G1=49.4+/-24.8, G2=47.2+/-30.1 and G3=56.1+/-38.2) at 48 h and pain scores at 12, 24, 36 and 48 h post-surgery were not significantly different among the groups [G1 (n=38), G2 (n=38) and G3 (n=38)]. Side effect profiles were similar across groups. Six months after surgery, the number of patients who reported chronic post-surgical pain (G1=10, G2=12 and G3=9) and the severity of the pain (G1=4.2+/-2.9, G2=4.1+/-2.2 and G3=4.9+/-2.2) did not differ significantly among the groups (P>0.05).

CONCLUSIONS

A single 600 mg dose of gabapentin given pre-operatively or post-operatively does not reduce morphine consumption or pain scores in hospital or at 6 months after hip arthroplasty within the context of spinal anesthesia and a robust multimodal analgesia regimen.