Fibromyalgia Survey Criteria Are Associated with Increased Postoperative Opioid Consumption in Women Undergoing Hysterectomy

Development and Validation of a Prediction Model for Pain and Functional Outcomes After Lumbar Spine Surgery

Importance

Functional impairment and pain are common indications for the initiation of lumbar spine surgery, but information about expected improvement in these patient-reported outcome (PRO) domains is not readily available to most patients and clinicians considering this type of surgery.

Objective

To assess population-level PRO response after lumbar spine surgery, and develop/validate a prediction tool for PRO improvement.

Design, Setting, and Participants

This statewide multicenter cohort was based at 15 Washington state hospitals representing approximately 75% of the state's spine fusion procedures. The Spine Surgical Care and Outcomes Assessment Program and the survey center at the Comparative Effectiveness Translational Network prospectively collected clinical and PRO data from adult candidates for lumbar surgery, preoperatively and postoperatively, between 2012 and 2016. Prediction models were derived for PRO improvement 1 year after lumbar fusion surgeries on a random sample of 85% of the data and were validated in the remaining 15%. Surgical candidates from 2012 through 2015 were included; follow-up surveying continued until December 31, 2016, and data analysis was completed from July 2016 to April 2017.

Main Outcomes and Measures

Functional improvement, defined as a reduction in Oswestry Disability Index score of 15 points or more; and back pain and leg pain improvement, defined a reduction in Numeric Rating Scale score of 2 points or more.

Results

A total of 1965 adult lumbar surgical candidates (mean [SD] age, 61.3 [12.5] years; 944 [59.6%] female) completed baseline surveys before surgery and at least 1 postoperative follow-up survey within 3 years. Of these, 1583 (80.6%) underwent elective lumbar fusion procedures; 1223 (77.3%) had stenosis, and 1033 (65.3%) had spondylolisthesis. Twelve-month follow-up participation rates for each outcome were between 66% and 70%. Improvements were reported in function, back pain, and leg pain at 12 months by 306 of 528 surgical patients (58.0%), 616 of 899 patients (68.5%), and 355 of 464 patients (76.5%), respectively, whose baseline scores indicated moderate to severe symptoms. Among nonoperative patients, 35 (43.8%), 47 (53.4%), and 53 (63.9%) reported improvements in function, back pain, and leg pain, respectively. Demographic and clinical characteristics included in the final prediction models were age, sex, race, insurance status, American Society of Anesthesiologists score, smoking status, diagnoses, prior surgery, prescription opioid use, asthma, and baseline PRO scores. The models had good predictive performance in the validation cohort (concordance statistic, 0.66-0.79) and were incorporated into a patient-facing, web-based interactive tool (https://becertain.shinyapps.io/lumbar_fusion_calculator).

Conclusions and Relevance

The PRO response prediction tool, informed by population-level data, explained most of the variability in pain reduction and functional improvement after surgery. Giving patients accurate information about their likelihood of outcomes may be a helpful component in surgery decision making.

Fibromyalgia and Shoulder Surgery: A Systematic Review and a Critical Appraisal of the Literature

Fibromyalgia is a common musculoskeletal syndrome characterized by chronic widespread pain and other systemic manifestations, which has demonstrated a contribution to higher postoperative analgesic consumption to other surgeries such as hysterectomies and knee and hip replacements. The aim of this review is to search current literature for studies considering the impact of fibromyalgia on clinical outcomes of patients undergoing shoulder surgery. A systematic literature review was conducted in PubMed/Medline, Embase, and ClinicalTrials.gov in February 2019. Studies were selected based on the following participants, interventions, comparisons, outcomes, and study design criteria: adult patients undergoing surgery for shoulder pain (P); diagnosis of fibromyalgia (I); patients without fibromyalgia (C); outcome of surgery in terms of pain or analgesic or non-steroidal anti-inflammatory drugs consumption (O); case series, retrospective studies, observational studies, open-label studies, randomized clinical trials, systematic reviews and meta-analyses were included (S). Authors found 678 articles, of which four were found eligible. One retrospective study showed that patients with fibromyalgia had worse clinical postoperative outcomes; two retrospective studies reported a higher opioid prescription in patients with fibromyalgia and one prospective observational study found that a higher fibromyalgia survey score correlated with lower quality of recovery scores two days after surgery. The scarce and low-quality evidence available does not allow confirming that fibromyalgia has an impact on postoperative outcomes in shoulder surgery. Future studies specifically focusing on shoulder surgery outcomes may help improvement and personalization of the management of patients with fibromyalgia syndrome (PROSPERO 2019, CRD42019121180).

Probability of Opioid Prescription Refilling After Surgery: Does Initial Prescription Dose Matter?

OBJECTIVE

We sought to determine the correlation between the probability of postoperative opioid prescription refills and the amount of opioid prescribed, hypothesizing that a greater initial prescription yields a lower probability of refill.

BACKGROUND

Although current guidelines regarding opioid prescribing largely address chronic opioid use, little is known regarding best practices and postoperative care.

METHODS

We analyzed Optum Insight claims data from 2013 to 2014 for opioid-naïve patients aged 18 to 64 years who underwent major or minor surgical procedures (N = 26,520). Our primary outcome was the occurrence of an opioid refill within 30 postoperative days. Our primary explanatory variable was the total oral morphine equivalents provided in the initial postoperative prescription. We used logistic regression to examine the probability of an additional refill by initial prescription strength, adjusting for patient factors.

RESULTS

We observed that 8.67% of opioid-naïve patients refilled their prescriptions. Across procedures, the probability of a single postoperative refill did not change with an increase with initial oral morphine equivalents prescribed. Instead, patient factors were correlated with the probability of refill, including tobacco use [odds ratio (OR) 1.42, 95% confidence interval (CI) 1.23-1.57], anxiety (OR 1.30, 95% CI 1.15-1.47), mood disorders (OR 1.28. 95% CI 1.13-1.44), alcohol or substance abuse disorders (OR 1.43, 95% CI 1.12-1.84), and arthritis (OR 1.21, 95% CI 1.10-1.34).

CONCLUSIONS

The probability of refilling prescription opioids after surgery was not correlated with initial prescription strength, suggesting surgeons could prescribe smaller prescriptions without influencing refill requests. Future research that examines the interplay between pain, substance abuse, and mental health could inform strategies to tailor opioid prescribing for patients.

Predicting chronic pain after major traumatic injury

Background and aims

Chronic pain after traumatic injury and surgery is highly prevalent, and associated with substantial psychosocial co-morbidities and prolonged opioid use. It is currently unclear whether predicting chronic post-injury pain is possible. If so, it is unclear if predicting chronic post-injury pain requires a comprehensive set of variables or can be achieved only with data available from the electronic medical records. In this prospective study, we examined models to predict pain at the site of injury 3–6 months after hospital discharge among adult patients after major traumatic injury requiring surgery. Two models were developed: one with a comprehensive set of predictors and one based only on variables available in the electronic medical records.

Methods

We examined pre-injury and post-injury clinical variables, and clinical management of pain. Patients were interviewed to assess chronic pain, defined as the presence of pain at the site of injury. Prediction models were developed using forward stepwise regression, using follow-up surveys at 3–6 months. Potential predictors identified a priori were: age; sex; presence of pre-existing chronic pain; intensity of post-operative pain at 6 h; in-hospital opioid consumption; injury severity score (ISS); location of trauma, defined as body region; use of regional analgesia intra- and/or post-operatively; pre-trauma PROMIS Depression, Physical Function, and Anxiety scores; in-hospital Widespread Pain Index and Symptom Severity Score; and number of post-operative non-opioid medications. After the final model was developed, a reduced model, based only on variables available in the electronic medical record was run to understand the “value add” of variables taken from study-specific instruments.

Results

Of 173 patients who completed the baseline interview, 112 completed the follow-up within 3–6 months. The prevalence of chronic pain was 66%. Opioid use increased from 16% pre-injury to 28% at 3–6 months. The final model included six variables, from an initial set of 24 potential predictors. The apparent area under the ROC curve (AUROC) of 0.78 for predicting pain 3–6 months was optimism-corrected to 0.73. The reduced final model, using only data available from the electronic health records, included post-surgical pain score at 6 h, presence of a head injury, use of regional analgesia, and the number of post-operative non-opioid medications used for pain relief. This reduced model had an apparent AUROC of 0.76, optimism-corrected to 0.72.

Conclusions

Pain 3–6 months after trauma and surgery is highly prevalent and associated with an increase in opioid use. Chronic pain at the site of injury at 3–6 months after trauma and surgery may be predicted during hospitalization by using routinely collected clinical data.

Implications

If our model is validated in other populations, it would provide a tool that can be easily implemented by any provider with access to medical records. Patients at risk of developing chronic pain could be selected for studies on preventive strategies, thereby concentrating the interventions to patients who are most likely to transition to chronic pain.

Medial branch radiofrequency ablation outcomes in patients with centralized pain

BACKGROUND AND OBJECTIVES

We hypothesized that patients with characteristics of centralized pain (fibromyalgia (FM)-like phenotype) would be less likely to respond to radiofrequency ablation (RFA), which may explain some of the failures of this peripherally directed therapy.

METHODS

We conducted a prospective, observational study of patients undergoing RFA using a number of validated self-report measures of pain, mood and function. The 2011 Fibromyalgia Survey Criteria were used to assess for symptoms of centralized pain and was the primary predictor of interest. We constructed multivariable linear regression models to evaluate covariates independently associated with change in pain 3 months after RFA.

RESULTS

141 patients scheduled for medial branch blocks were enrolled in the study; 55 underwent RFA (51 with complete 3 months' follow-up). Patients with higher FM scores had less improvement in overall body pain; however, this was not statistically significant (adjusted mean change in pain FM+0.41, FM-1.11, p=0.396). In a secondary analysis, the FM score was not associated with change in back pain (p=0.720), with both groups improving equally. This cohort also reported significant improvement in anxiety, physical function, catastrophizing, and sleep disturbance at 3 months after RFA.

CONCLUSIONS

Although patients with high baseline centralized pain exhibited less improvement in overall pain, this trend was not statistically significant, possibly due to insufficient power. The same trend was not seen with change in spine pain with both groups improving equally. Centralized pain patients may have less improvement in overall pain but may have equal improvement in their site-specific pain levels after localized interventions.

Chronic pain syndromes: overlapping phenotypes with common mechanisms

The common chronic pain syndromes of fibromyalgia, regional pain syndrome, and complex regional pain syndrome have been made to appear separate because they have been historically described by different groups and with different criteria, but they are really phenotypically accented expressions of the same processes triggered by emotional distress and filtered or modified by genetics, psychology, and local physical factors.

Designing and conducting proof-of-concept chronic pain analgesic clinical trials

Introduction:

The evolution of pain treatment is dependent on successful development and testing of interventions. Proof-of-concept (POC) studies bridge the gap between identification of a novel target and evaluation of the candidate intervention's efficacy within a pain model or the intended clinical pain population.

Methods:

This narrative review describes and evaluates clinical trial phases, specific POC pain trials, and approaches to patient profiling.

Results:

We describe common POC trial designs and their value and challenges, a mechanism-based approach, and statistical issues for consideration.

Conclusion:

Proof-of-concept trials provide initial evidence for target use in a specific population, the most appropriate dosing strategy, and duration of treatment. A significant goal in designing an informative and efficient POC study is to ensure that the study is safe and sufficiently sensitive to detect a preliminary efficacy signal (ie, a potentially valuable therapy). Proof-of-concept studies help avoid resources wasted on targets/molecules that are not likely to succeed. As such, the design of a successful POC trial requires careful consideration of the research objective, patient population, the particular intervention, and outcome(s) of interest. These trials provide the basis for future, larger-scale studies confirming efficacy, tolerability, side effects, and other associated risks.

Self-reported cumulative medical opioid exposure and subjective responses on first use of opioids predict analgesic and subjective responses to placebo-controlled opioid administration

BACKGROUND AND OBJECTIVES

To expand the evidence base needed to enable personalized pain medicine, we evaluated whether self-reported cumulative exposure to medical opioids and subjective responses on first opioid use predicted responses to placebo-controlled opioid administration.

METHODS

In study 1, a survey assessing cumulative medical opioid exposure and subjective responses on first opioid use was created (History of Opioid Medical Exposure (HOME)) and psychometric features documented in a general sample of 307 working adults. In study 2, 49 patients with chronic low back pain completed the HOME and subsequently rated back pain intensity and subjective opioid effects four times after receiving saline placebo or intravenous morphine (four incremental doses) in two separate double-blinded laboratory sessions. Placebo-controlled morphine effects were derived for all outcomes.

RESULTS

Two HOME subscales were supported: cumulative opioid exposure and euphoric response, both demonstrating high test-retest reliability (Intraclass Correlation Coefficients > 0.93) and adequate internal consistency (Revelle's Omega Total = 0.73-0.77). In study 2, higher cumulative opioid exposure scores were associated with significantly greater morphine-related reductions in back pain intensity (p=0.02), but not with subjective drug effects. Higher euphoric response subscale scores were associated with significantly lower overall perceived morphine effect (p=0.003), less sedation (p=0.04), greater euphoria (p=0.03) and greater desire to take morphine again (p=0.02).

DISCUSSION

Self-reports of past exposure and responses to medical opioid analgesics may have utility for predicting subsequent analgesic responses and subjective effects. Further research is needed to establish the potential clinical and research utility of the HOME.

TRIAL REGISTRATION NUMBER

NCT02469077.

Risk factors for postoperative opioid use after elective shoulder arthroplasty

BACKGROUND

The opioid epidemic remains a serious issue in the United States with significant impact to the medical and socioeconomic welfare of communities. We sought to determine baseline opioid use in patients undergoing shoulder arthroplasty (SA) and identify patient characteristics, comorbidities, and surgical risk factors associated with postoperative opioid use.

METHODS

A Shoulder Arthroplasty Registry identified the number of dispensed opioid medication prescriptions (Rxs) in the first postoperative year in patients who underwent elective primary SA from 2008 to 2014. We used Poisson regression to study the effect of preoperative risks factors on number of dispensed opioid Rxs in the first postoperative year, evaluated quarterly (Q1: days 0-90, Q2: days 91-180, Q3: days 181-270, Q4: days 271-360).

RESULTS

Included were 4243 SAs from 3996 patients, and 75% used opioids in the 1-year preoperative period. The factors associated with increased opioid use in all postoperative quarters (Q4 incident rate ratio [IRR] shown) were age <60 years (IRR, 1.40; 95% confidence interval [CI], 1.29-1.51), preoperative opioid use (1-4 Rxs: IRR, 2.15; 95% CI, 1.85-2.51; ≥5 Rxs: IRR, 9.83; 95% CI , 8.53-11.32), anxiety (IRR, 1.11; 95% CI, 1.03-1.20), opioid dependence (IRR, 1.23; 95% CI, 1.05-1.43), substance abuse (IRR, 1.17; 95% CI, 1.07-1.28), and general chronic pain (IRR, 1.38; 95% CI, 1.28-1.50).

CONCLUSION

Opioid usage in patients undergoing SA is widespread at 1 year, with three-fourths of patients having been dispensed at least one Rx. These findings emphasize the need for surgeon and patient awareness as well as education in the management of postoperative opioid usage associated with the indicated conditions. Surgeons may consider these risk factors for preoperative risk stratification and targeted deployment of preventative strategies.

Effect of new persistent opioid use on physiologic and psychologic outcomes following bariatric surgery

INTRODUCTION

New persistent opioid use following surgery is a common iatrogenic complication, developing in roughly 6% of patients after elective surgery. Despite increased awareness of misuse and associated morbidity, opioids remain the cornerstone of pain management in bariatric surgery. The potential impact of new persistent opioid use on long-term postoperative outcomes is unknown. We sought to determine the relationship between new persistent opioid use and 1-year postoperative outcomes for patients undergoing bariatric surgery.

METHODS

Using data from the MBSC registry, we identified patients undergoing primary bariatric surgery between 2006 and 2016. Using previously validated patient-reported survey methodology, we evaluated patient opioid use preoperatively and at 1 year following surgery. New persistent use was defined as a previously opioid-naïve patient who self-reported opioid use 1 year after surgery. We used multivariable logistic regression models to evaluate the association between new persistent opioid use, risk-adjusted weight loss, and psychologic outcomes (psychological wellbeing, body image, and depression).

RESULTS

27,799 patients underwent primary bariatric surgery between 2006 and 2016. Among opioid-naïve patients, the rate of new persistent opioid use was 6.3%. At 1-year after surgery, patients with new persistent opioid user lost significantly less excess body weight compared to those without new persistent use (57.6% vs. 60.3%; p < 0.0001). Patients with new persistent opioid use had significantly worse psychological wellbeing (35.0 vs. 33.1; p < 0.0001), body image (19.9 vs. 18.0; p < 0.0001), and depression scores (2.4 vs. 5.0; p < 0.0001). New persistent opioid users also reported less overall satisfaction with their bariatric surgery (75.1% vs. 85.7%; p < 0.0001).

CONCLUSIONS

New persistent opioid use is common following bariatric surgery and associated with significantly worse physiologic and psychologic outcomes. More effective screening and postoperative surveillance tools are needed to identify these patients, who likely require more aggressive counseling and treatment to maximize the benefits of bariatric surgery.

Sensory sensitivity and symptom severity represent unique dimensions of chronic pain: a MAPP Research Network study

Chronic overlapping pain conditions (COPCs) are characterized by aberrant central nervous system processing of pain. This "centralized pain" phenotype has been described using a large and diverse set of symptom domains, including the spatial distribution of pain, pain intensity, fatigue, mood imbalances, cognitive dysfunction, altered somatic sensations, and hypersensitivity to external stimuli. Here, we used 3 cohorts, including patients with urologic chronic pelvic pain syndrome, a mixed pain cohort with other COPCs, and healthy individuals (total n = 1039) from the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network to explore the factor structure of symptoms of centralized pain. Using exploratory and confirmatory factor analysis, we identified 2 general factors in all 3 cohorts, one characterized by a broad increased sensitivity to internal somatic sensations,environmental stimuli, and diffuse pain, termed Generalized Sensory Sensitivity, and one characterized by constitutional symptoms-Sleep, Pain, Affect, Cognition, Energy (SPACE). Longitudinal analyses in the urologic chronic pelvic pain syndrome cohort found the same 2-factor structure at month 6 and 1 year, suggesting that the 2-factor structure is reproducible over time. In secondary analyses, we found that Generalized Sensory Sensitivity particularly is associated with the presence of comorbid COPCs, whereas SPACE shows modest associations with measures of disability and urinary symptoms. These factors may represent an important and distinct continuum of symptoms that are indicative of the centralized pain phenotype at high levels. Future research of COPCs should accommodate the measurement of each factor.

The Impact of Education and Prescribing Guidelines on Opioid Prescribing for Breast and Melanoma Procedures

BACKGROUND

Excessive opioid prescribing is common in surgical oncology, with 72% of prescribed opioids going unused after curative-intent surgery. In this study, we sought to reduce opioid prescribing after breast and melanoma procedures by designing and implementing an intervention focused on education and prescribing guidelines, and then evaluating the impact of this intervention.

METHODS

In this single-institution study, we designed and implemented an intervention targeting key factors identified in qualitative interviews. This included mandatory education for prescribers, evidence-based prescribing guidelines, and standardized patient instructions. After the intervention, interrupted time-series analysis was used to compare the mean quantity of opioid prescribed before and after the intervention (July 2016-September 2017). We also evaluated the frequency of opioid prescription refills.

RESULTS

During the study, 847 patients underwent breast or melanoma procedures and received an opioid prescription. For mastectomy or wide local excision for melanoma, the mean quantity of opioid prescribed immediately decreased by 37% after the intervention (p = 0.03), equivalent to 13 tablets of oxycodone 5 mg. For lumpectomy or breast biopsy, the mean quantity of opioid prescribed decreased by 42%, or 12 tablets of oxycodone 5 mg (p = 0.07). Furthermore, opioid prescription refills did not significantly change for mastectomy/wide local excision (13% vs. 14%, p = 0.8), or lumpectomy/breast biopsy (4% vs. 5%, p = 0.7).

CONCLUSION

Education and prescribing guidelines reduced opioid prescribing for breast and melanoma procedures without increasing the need for refills. This suggests further reductions in opioid prescribing may be possible, and provides rationale for implementing similar interventions for other procedures and practice settings.

Opioid Prescribing After Curative-Intent Surgery: A Qualitative Study Using the Theoretical Domains Framework

BACKGROUND

Excessive opioid prescribing is common after curative-intent surgery, but little is known about what factors influence prescribing behaviors among surgeons. To identify targets for intervention, we performed a qualitative study of opioid prescribing after curative-intent surgery using the Theoretical Domains Framework, a well-established implementation science method for identifying factors influencing healthcare provider behavior.

METHODS

Prior to data collection, we constructed a semi-structured interview guide to explore decision making for opioid prescribing. We then conducted interviews with surgical oncology providers at a single comprehensive cancer center. Interviews were recorded, transcribed verbatim, then independently coded by two investigators using the Theoretical Domains Framework to identify theoretical domains relevant to opioid prescribing. Relevant domains were then linked to behavior models to select targeted interventions likely to improve opioid prescribing.

RESULTS

Twenty-one subjects were interviewed from November 2016 to May 2017, including attending surgeons, resident surgeons, physician assistants, and nurses. Five theoretical domains emerged as relevant to opioid prescribing: environmental context and resources; social influences; beliefs about consequences; social/professional role and identity; and goals. Using these domains, three interventions were identified as likely to change opioid prescribing behavior: (1) enablement (deploy nurses during preoperative visits to counsel patients on opioid use); (2) environmental restructuring (provide on-screen prompts with normative data on the quantity of opioid prescribed); and (3) education (provide prescribing guidelines).

CONCLUSIONS

Key determinants of opioid prescribing behavior after curative-intent surgery include environmental and social factors. Interventions targeting these factors are likely to improve opioid prescribing in surgical oncology.

Phenotypic Features of Central Sensitization

PURPOSE

The current manuscript reviews approaches for phenotyping central sensitization (CS).

METHODS

The manuscript covers the concept of diagnostic phenotyping, use of endophenotypes, biomarkers, and symptom clusters. Specifically, the components of CS that include general sensory sensitivity (assessed by quantitative sensory testing) and a symptom cluster denoting sleep difficulties, pain, affect, cognitive difficulties, and low energy (S.P.A.C.E.).

RESULTS

Each of the assessment domains are described with reference to CS and their presence in chronic overlapping pain conditions (COPCs) - conditions likely influenced by CS.

CONCLUSIONS

COPCs likely represent clinical diagnostic phenotypes of CS. Components of CS can also be assessed using QST or self-report instruments designed to assess single elements of CS or more general composite indices.

Effect of Fibromyalgia Symptoms on Outcome of Spinal Surgery

Objectives

To evaluate the effect of presurgical symptoms characteristic of fibromyalgia on the postsurgical outcome of patients undergoing spinal surgery.

Methods

In this observational cohort study, participants were patients scheduled for spinal surgery, including cervical or lumbar laminectomy and foraminectomy. Presurgical evaluation included physical examination and manual dolorimetry. Questionnaires included the widespread pain index (WPI), symptom severity scale (SSS), and SF-36. Postsurgical evaluation performed at 10-12 weeks included questionnaires, physical examination, and dolorimetry.

Results

Forty patients (21 male, 19 female) were recruited. Four patients (10%) fulfilled American College of Rheumatology (ACR) 1990 fibromyalgia; nine patients fulfilled 2010 criteria (22.5%). Overall, a significant 34% reduction in WPI was observed postsurgically ( P  < 0.01), but no significant change was observed in SSS. Comparing outcomes for patients fulfilling and not fulfilling fibromyalgia criteria, fibromyalgia syndrome (FMS)-negative patients experienced highly significant reductions of both SSS and WPI (-50.1% and -42.9%, respectively, P  < 0.01), while FMS-positive patients experienced no reduction of SSS symptoms and only a marginally significant reduction in WPI (-20.3%, P  = 0.04). A significant negative correlation was observed between results of presurgical WPI and change in physical role functioning SF-36 component postsurgically. A significant negative correlation was observed between presurgical SSS and change in composite physical functioning SF-36 component. Regression analysis demonstrated a difference in trend between FMS-positive and FMS-negative patients regarding postop changes in SSS, as well as a difference in trend regarding the general health role limitation due to emotional problems and pain components of the SF-36.

Conclusions

Fibromyalgia symptoms were highly prevalent among patients scheduled for spinal surgery. A negative correlation was observed between presurgical severity of fibromyalgia symptoms and components of postsurgical SF-36. Patients with symptoms typical of fibromyalgia may have a less favorable outcome after spinal surgery. The clinical utility of surgical intervention in such patients should be carefully evaluated, and treatment specific for fibromyalgia might be considered before embarking on a surgical course.

The ACTTION-APS-AAPM Pain Taxonomy (AAAPT) Multidimensional Approach to Classifying Acute Pain Conditions

Objective

With the increasing societal awareness of the prevalence and impact of acute pain, there is a need to develop an acute pain classification system that both reflects contemporary mechanistic insights and helps guide future research and treatment. Existing classifications of acute pain conditions are limiting, with a predominant focus on the sensory experience (e.g., pain intensity) and pharmacologic consumption. Consequently, there is a need to more broadly characterize and classify the multidimensional experience of acute pain.

Setting

Consensus report following expert panel involving the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION), American Pain Society (APS), and American Academy of Pain Medicine (AAPM).

Methods

As a complement to a taxonomy recently developed for chronic pain, the ACTTION public-private partnership with the US Food and Drug Administration, the APS, and the AAPM convened a consensus meeting of experts to develop an acute pain taxonomy using prevailing evidence. Key issues pertaining to the distinct nature of acute pain are presented followed by the agreed-upon taxonomy. The ACTTION-APS-AAPM Acute Pain Taxonomy will include the following dimensions: 1) core criteria, 2) common features, 3) modulating factors, 4) impact/functional consequences, and 5) putative pathophysiologic pain mechanisms. Future efforts will consist of working groups utilizing this taxonomy to develop diagnostic criteria for a comprehensive set of acute pain conditions.

Perspective

The ACTTION-APS-AAPM Acute Pain Taxonomy (AAAPT) is a multidimensional acute pain classification system designed to classify acute pain along the following dimensions: 1) core criteria, 2) common features, 3) modulating factors, 4) impact/functional consequences, and 5) putative pathophysiologic pain mechanisms.

Conclusions

Significant numbers of patients still suffer from significant acute pain, despite the advent of modern multimodal analgesic strategies. Mismanaged acute pain has a broad societal impact as significant numbers of patients may progress to suffer from chronic pain. An acute pain taxonomy provides a much-needed standardization of clinical diagnostic criteria, which benefits clinical care, research, education, and public policy. For the purposes of the present taxonomy, acute pain is considered to last up to seven days, with prolongation to 30 days being common. The current understanding of acute pain mechanisms poorly differentiates between acute and chronic pain and is often insufficient to distinguish among many types of acute pain conditions. Given the usefulness of the AAPT multidimensional framework, the AAAPT undertook a similar approach to organizing various acute pain conditions.

The ACTTION-APS-AAPM Pain Taxonomy (AAAPT) Multidimensional Approach to Classifying Acute Pain Conditions

OBJECTIVE

With the increasing societal awareness of the prevalence and impact of acute pain, there is a need to develop an acute pain classification system that both reflects contemporary mechanistic insights and helps guide future research and treatment. Existing classifications of acute pain conditions are limiting, with a predominant focus on the sensory experience (eg, pain intensity) and pharmacologic consumption. Consequently, there is a need to more broadly characterize and classify the multidimensional experience of acute pain.

SETTING

Consensus report following expert panel involving the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION), American Pain Society (APS), and American Academy of Pain Medicine (AAPM).

METHODS

As a complement to a taxonomy recently developed for chronic pain, the ACTTION public-private partnership with the US Food and Drug Administration, the APS, and the AAPM convened a consensus meeting of experts to develop an acute pain taxonomy using prevailing evidence. Key issues pertaining to the distinct nature of acute pain are presented followed by the agreed-upon taxonomy. The ACTTION-APS-AAPM Acute Pain Taxonomy will include the following dimensions: 1) core criteria, 2) common features, 3) modulating factors, 4) impact/functional consequences, and 5) putative pathophysiologic pain mechanisms. Future efforts will consist of working groups utilizing this taxonomy to develop diagnostic criteria for a comprehensive set of acute pain conditions.

PERSPECTIVE

The ACTTION-APS-AAPM Acute Pain Taxonomy (AAAPT) is a multidimensional acute pain classification system designed to classify acute pain along the following dimensions: 1) core criteria, 2) common features, 3) modulating factors, 4) impact/functional consequences, and 5) putative pathophysiologic pain mechanisms.

CONCLUSIONS

Significant numbers of patients still suffer from significant acute pain, despite the advent of modern multimodal analgesic strategies. Mismanaged acute pain has a broad societal impact as significant numbers of patients may progress to suffer from chronic pain. An acute pain taxonomy provides a much-needed standardization of clinical diagnostic criteria, which benefits clinical care, research, education, and public policy. For the purposes of the present taxonomy, acute pain is considered to last up to seven days, with prolongation to 30 days being common. The current understanding of acute pain mechanisms poorly differentiates between acute and chronic pain and is often insufficient to distinguish among many types of acute pain conditions. Given the usefulness of the AAPT multidimensional framework, the AAAPT undertook a similar approach to organizing various acute pain conditions.

Endogenous Opiates and Behavior: 2016

This paper is the thirty-ninth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2016 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Changes in Anxiety and Depression Are Mediated by Changes in Pain Severity in Patients Undergoing Lower-Extremity Total Joint Arthroplasty

BACKGROUND

Depression and anxiety are common comorbidities in chronic pain including osteoarthritis patients undergoing total joint arthroplasty (TJA). What is not clear is whether psychiatric comorbidity precedes the manifestation of painful states or represents a reaction to living with chronic pain and associated functional impairment. The objective of this research was to explore whether decreases in depressive and anxiety symptoms after lower-extremity TJA could be due to postsurgical reductions in pain.

METHODS

We conducted a secondary analysis of data from 1448 TJA patients enrolled in the Analgesics Outcome Study. Patients completed measures of pain intensity, functional status, and depressive and anxiety symptoms preoperatively and at 3 and 6 months postoperatively. Data were analyzed using a structural equation modeling approach.

RESULTS

We found that improvement in pain and physical function from baseline to 6 months postoperatively was associated with improvement in depression and anxiety symptoms. We also found that a change in overall body pain at 3 months after surgery significantly mediated changes in both the depression and anxiety scores at 6 months after surgery even when controlling for age, sex, baseline body pain, education, opioid use, and type of surgery.

CONCLUSIONS

Presurgical affective symptoms not only have an effect on change in postsurgical pain, whereby lower preoperative scores on depression and anxiety were associated with lower postsurgical pain, but also postsurgical decreases in pain were associated with lower levels of depression and anxiety after surgery. Taking these points into consideration may prove useful in working toward better outcomes for TJA.

Normalizing fibromyalgia as a chronic illness

Fibromyalgia (FM) is a complex chronic disease that affects 3-10% of the general adult population and is principally characterized by widespread pain, and is often associated with disrupted sleep, fatigue, and comorbidities, among other symptoms. There are many gaps in our knowledge of FM, such that, compared with other chronic illnesses including diabetes, rheumatoid arthritis, and asthma, it is far behind in terms of provider understanding and therapeutic approaches. The experience that healthcare professionals (HCPs) historically gained in developing approaches to manage and treat patients with these chronic illnesses may help show how they can address similar problems in patients with FM. In this review, we examine some of the issues around the management and treatment of FM, and discuss how HCPs can implement appropriate strategies for the benefit of patients with FM. These issues include understanding that FM is a legitimate condition, the benefits of prompt diagnosis, use of non-drug and pharmacotherapies, patient and HCP education, watchful waiting, and assessing patients by FM domain so as not to focus exclusively on one symptom to the detriment of others. Developing successful approaches is of particular importance for HCPs in the primary care setting who are in the ideal position to provide long-term care for patients with FM. In this way, FM may be normalized as a chronic illness to the benefit of both patients and HCPs.

Do Resting Plasma β-Endorphin Levels Predict Responses to Opioid Analgesics?

OBJECTIVES

Clinically feasible predictors of opioid analgesic responses for use in precision pain medicine protocols are needed. This study evaluated whether resting plasma β-endorphin (BE) levels predicted responses to an opioid analgesic, and whether chronic pain status or sex moderated these effects.

METHODS

Participants included 73 individuals with chronic low back pain (CLBP) and 88 pain-free controls, all using no daily opioid analgesics. Participants attended 2 identical laboratory sessions during which they received either intravenous morphine (0.08 mg/kg) or saline placebo, with blood samples obtained before drug administration to assay resting plasma BE levels. Once peak drug activity was achieved in each session, participants engaged in an ischemic forearm pain task (ISC) and a heat pain task. Morphine analgesic effects were derived reflecting the difference in pain outcomes between placebo and morphine conditions.

RESULTS

In hierarchical regressions, significant Type (CLBP vs. control)×BE interactions (Ps<0.05) were noted for morphine effects on ISC tolerance, ISC intratask pain ratings, and thermal VAS unpleasantness ratings. These interactions derived primarily from associations between higher BE levels and smaller morphine effects restricted to the CLBP subgroup. All other BE-related effects, including sex interactions, for predicting morphine analgesia failed to reach statistical significance.

DISCUSSION

BE was a predictor of morphine analgesia for only 3 out of 9 outcomes examined, with these effects moderated by chronic pain status but not sex. On the whole, results do not suggest that resting plasma BE levels are likely to be a clinically useful predictor of opioid analgesic responses.

The Fibromyalgia Survey Score Correlates With Preoperative Pain Phenotypes But Does Not Predict Pain Outcomes After Shoulder Arthroscopy

OBJECTIVES

Fibromyalgia (FM) characteristics can be evaluated using a simple, self-reported measure that correlates with postoperative opioid consumption after lower-extremity joint arthroplasty. The purpose of this study was to determine whether preoperative pain history and the FM survey score can predict postoperative outcomes after shoulder arthroscopy, which may cause moderate to severe pain.

MATERIALS AND METHODS

In this prospective study, 100 shoulder arthroscopy patients completed preoperative validated self-report measures to assess baseline quality of recovery score, physical functioning, depression, anxiety, and neuropathic pain. FM characteristics were evaluated using a validated measure of widespread pain and comorbid symptoms on a 0 to 31 scale. Outcomes were assessed on postoperative day 2 (opioid consumption [primary], pain, physical functioning, quality of recovery score), and day 14 (opioid consumption, pain).

RESULTS

FM survey scores ranged from 0 to 13. The cohort was divided into tertiles for univariate analyses. Preoperative depression and anxiety (P<0.001) and neuropathic pain (P=0.008) were higher, and physical functioning was lower (P<0.001), in higher FM survey score groups. The fibromyalgia survey score was not associated with postoperative pain or opioid consumption; however, it was independently associated with poorer quality of recovery scores (P=0.001). The only independent predictor of postoperative opioid use was preoperative opioid use (P=0.038).

DISCUSSION

FM survey scores were lower than those in a previous study of joint arthroplasty. Although they distinguished a negative preoperative pain phenotype, FM scores were not independently associated with postoperative opioid consumption. Further research is needed to elucidate the impact of a FM-like phenotype on postoperative analgesic outcomes.

Opioid Prescribing Patterns, Patient Use, and Postoperative Pain After Hysterectomy for Benign Indications

OBJECTIVE

To quantify physician prescribing patterns and patient opioid use in the 2 weeks after hysterectomy at an academic institution and to determine whether patient factors predict postsurgical opioid use and pain recovery.

METHODS

We conducted a prospective quality initiative study by recruiting all English-speaking patients undergoing hysterectomy for benign, nonobstetric indications at a university hospital between August 2015 and December 2015, excluding those with major medical morbidities or substance abuse. Before hysterectomy, patients completed the Fibromyalgia Survey, a validated measure of centralized pain. After hysterectomy, opioid use (converted to oral morphine equivalents) and pain scores (0-10 numeric rating scale) were collected by a daily diary and a structured telephone interview 14 days after surgery. Primary outcomes were total opioid prescribed and consumed in the 2 weeks after hysterectomy. Secondary outcomes included daily opioid use and daily pain severity for 14 days after hysterectomy.

RESULTS

Of 103 eligible patients, 102 (99%) agreed to participate, including 44 (43.1%) laparoscopic, 42 (41.2%) vaginal, and 16 (15.7%) abdominal hysterectomies. Telephone surveys were completed on 89 (87%) participants; diaries were returned from 60 (59%) participants. Diary nonresponders had different baseline characteristics than nonresponders. Median amount of opioid prescribed was 200 oral morphine equivalents (interquartile range 150-250). Patients reported using approximately half of the opioids prescribed with a median excess of 110 morphine equivalents (interquartile range 40-150). The best fit model of total opioid consumption identified preoperative Fibromyalgia Survey Score, overall body pain, preoperative opioid use, prior endometriosis, abdominal hysterectomy (compared with laparoscopic), and uterine weight as significant predictors. Highest tertile of Fibromyalgia Survey Score was associated with greater daily opioid consumption (13.9 [95% CI 3.0-24.8] greater oral morphine equivalents at baseline, P=.02).

CONCLUSION

Gynecologists at a large academic medical center prescribe twice the amount of opioids than the average patient uses after hysterectomy. A personalized approach to prescribing opioids for postoperative pain should be considered.

A Conceptual Framework for Understanding Unintended Prolonged Opioid Use

An urgent need exists to better understand the transition from short-term opioid use to unintended prolonged opioid use (UPOU). The purpose of this work is to propose a conceptual framework for understanding UPOU that posits the influence of 3 principal domains that include the characteristics of (1) individual patients, (2) the practice environment, and (3) opioid prescribers. Although no standardized method exists for developing a conceptual framework, the process often involves identifying corroborative evidence, leveraging expert opinion to identify factors for inclusion in the framework, and developing a graphic depiction of the relationships between the various factors and the clinical problem of interest. Key patient characteristics potentially associated with UPOU include (1) medical and mental health conditions; (2) pain etiology; (3) individual affective, behavioral, and neurophysiologic reactions to pain and opioids; and (4) sociodemographic factors. Also, UPOU could be influenced by structural and health care policy factors: (1) the practice environment, including the roles of prescribing clinicians, adoption of relevant practice guidelines, and clinician incentives or disincentives, and (2) the regulatory environment. Finally, characteristics inherent to clinicians that could influence prescribing practices include (1) training in pain management and opioid use; (2) personal attitudes, knowledge, and beliefs regarding the risks and benefits of opioids; and (3) professionalism. As the gatekeeper to opioid access, the behavior of prescribing clinicians directly mediates UPOU, with the 3 domains interacting to determine this behavior. This proposed conceptual framework could guide future research on the topic and allow plausible hypothesis-based interventions to reduce UPOU.

Fibromyalgia and the Prediction of Two-Year Changes in Functional Status in Rheumatoid Arthritis Patients

OBJECTIVE

Previous cross-sectional studies have shown that rheumatoid arthritis (RA) patients with fibromyalgia (FM) have higher disease activity, greater medical costs, and worse quality of life compared to RA patients without FM. We determined the impact of FM on 2-year changes in the functional status of RA patients in a prospective study.

METHODS

Subjects included participants in the Brigham Rheumatoid Arthritis Sequential Study who were enrolled in a substudy of the effects of pain in RA. Subjects completed questionnaires, including the Multi-Dimensional Health Assessment Questionnaire (MDHAQ) and Polysymptomatic Distress (PSD) scale, semiannually, and underwent physical examination and laboratory tests yearly.

RESULTS

Of the 156 included RA subjects, 16.7% had FM, while 83.3% did not. In a multivariable linear regression model adjusted for age, sex, race, baseline MDHAQ score, disease duration, rheumatoid factor/cyclic citrullinated peptide antibody seropositivity, disease activity, and psychological distress, RA patients with FM had a 0.14 greater 2-year increase in MDHAQ score than RA patients without FM (P = 0.021). In secondary analyses examining the association between continuous PSD scale score and change in MDHAQ, higher PSD scale scores were significantly associated with greater 2-year increases in MDHAQ score (β coefficient 0.013, P = 0.011).

CONCLUSION

Both the presence of FM and increasing number of FM symptoms predicted worsening of functional status among individuals with RA. Among individuals with RA and FM, the magnitude of the difference in changes in MDHAQ was 4- to 7-fold higher than typical changes in MDHAQ score among individuals with established RA.

Does association of opioid use with pain and function differ by fibromyalgia or widespread pain status?

Many consider chronic opioid therapy (COT) to be ineffective for fibromyalgia, but empirical evidence is limited. Among patients identified as initiating COT, we examined whether fibromyalgia was associated with different relationships of opioid use to pain and activity interference outcomes 12 months later. We obtained electronic data on diagnoses and opioid prescriptions. We obtained patient self-report data, including pain and activity interference measures, at baseline, 4 months, and 12 months. Among 1218 patients, 429 (35%) met our definition of fibromyalgia. Patients with and without fibromyalgia who had intermittent/lower-dose or regular/higher-dose opioid use at 12 months had similar 12-month pain intensity scores. However, among patients with minimal/no opioid use at 12 months, 12-month pain intensity was greater for those with fibromyalgia (adjusted mean = 5.15 [95% confidence interval, 4.80-5.51]; 0-10 scale) than for those without (4.44 [4.15-4.72]). Similar patterns were observed for 12-month activity interference. Among patients who discontinued opioids by 12 months, those with fibromyalgia were more likely to report bothersome side effects and less likely to report pain improvement as important reasons for discontinuation (P < 0.05). In sum, at 12 months, among patients who had discontinued opioids or used them minimally, those with fibromyalgia had worse outcomes and were less likely to have discontinued because of pain improvement. Among patients continuing COT, pain and activity interference outcomes were worse than those of patients with minimal/no opioid use and did not differ for those with fibromyalgia vs those with diverse other chronic pain conditions.

New Persistent Opioid Use Among Patients With Cancer After Curative-Intent Surgery

Purpose The current epidemic of prescription opioid misuse has increased scrutiny of postoperative opioid prescribing. Some 6% to 8% of opioid-naïve patients undergoing noncancer procedures develop new persistent opioid use; however, it is unknown if a similar risk applies to patients with cancer. We sought to define the risk of new persistent opioid use after curative-intent surgery, identify risk factors, and describe changes in daily opioid dose over time after surgery. Methods Using a national data set of insurance claims, we identified patients with cancer undergoing curative-intent surgery from 2010 to 2014. We included melanoma, breast, colorectal, lung, esophageal, and hepato-pancreato-biliary/gastric cancer. Primary outcomes were new persistent opioid use (opioid-naïve patients who continued filling opioid prescriptions 90 to 180 days after surgery) and daily opioid dose (evaluated monthly during the year after surgery). Logistic regression was used to identify risk factors for new persistent opioid use. Results A total of 68,463 eligible patients underwent curative-intent surgery and filled opioid prescriptions. Among opioid-naïve patients, the risk of new persistent opioid use was 10.4% (95% CI, 10.1% to 10.7%). One year after surgery, these patients continued filling prescriptions with daily doses similar to chronic opioid users ( P = .05), equivalent to six tablets per day of 5-mg hydrocodone. Those receiving adjuvant chemotherapy had modestly higher doses ( P = .002), but patients with no chemotherapy still had doses equivalent to five tablets per day of 5-mg hydrocodone. Across different procedures, the covariate-adjusted risk of new persistent opioid use in patients receiving adjuvant chemotherapy was 15% to 21%, compared with 7% to 11% for those with no chemotherapy. Conclusion New persistent opioid use is a common iatrogenic complication in patients with cancer undergoing curative-intent surgery. This problem requires changes to prescribing guidelines and patient counseling during the surveillance and survivorship phases of care.

Improvement in the Spatial Distribution of Pain, Somatic Symptoms, and Depression After a Weight Loss Intervention

Weight loss is known to improve pain localized to weight-bearing joints but it is not known how weight loss affects the spatial distribution of pain and associated somatic symptoms like fatigue. We sought to determine if weight loss using a low-calorie diet improves pain, affect, and somatic symptoms commonly associated with chronic pain conditions in an observational study. We also documented changes in inflammatory markers in serum before and after weight loss. Participants were 123 obese individuals undergoing a 12- to 16-week calorie restriction weight loss intervention. The spatial distribution of pain, symptom severity (eg, fatigue, sleep difficulties), depression, and total fibromyalgia scale scores were measured before and after weight loss. Pain (P = . 022), symptom severity (P = .004), depression (P < .001), and fibromyalgia scores (P = .004) improved after weight loss; men showed greater improvement than women on somatic symptoms and fibromyalgia scores (both P < .01). Those who lost at least 10% of body weight showed greater improvement than those who lost <10%. Levels of the regulatory cytokine interleukin-10 increased after the intervention (P = .002). Weight loss may improve diffuse pain and comorbid symptoms commonly seen in chronic pain participants.

PERSPECTIVE

This article presents the effect of a weight loss intervention on characteristics of chronic pain, including the spatial distribution of pain and comorbid somatic symptoms. Weight loss appeared to produce larger improvements in somatic symptoms for men.

Medication Treatment Efficacy and Chronic Orofacial Pain

Chronic pain in the orofacial region has always been a vexing problem for dentists to diagnose and treat effectively. For trigeminal neuropathic pain, there are 3 medications (gabapentinoids, tricyclic antidepressants, and serotonin-norepinephrine reuptake inhibitors) to use plus topical anesthetics that have therapeutic efficacy. For chronic daily headaches (often migraine in origin), 3 prophylactic medications have reasonable therapeutic efficacy (β-blockers, tricyclic antidepressants, and antiepileptic drugs). The 3 Food and Drug Administration-approved drugs for fibromyalgia (pregabalin, duloxetine, and milnacipran) are not robust, with poor efficacy. For osteroarthritis, nonsteroidal anti-inflammatory drugs have therapeutic efficacy and when gastritis contraindicates them, corticosteriod injections are helpful.

Pain Catastrophizing Moderates Relationships between Pain Intensity and Opioid Prescription: Nonlinear Sex Differences Revealed Using a Learning Health System

BACKGROUND

Pain catastrophizing is a maladaptive response to pain that amplifies chronic pain intensity and distress. Few studies have examined how pain catastrophizing relates to opioid prescription in outpatients with chronic pain.

METHODS

The authors conducted a retrospective observational study of the relationships between opioid prescription, pain intensity, and pain catastrophizing in 1,794 adults (1,129 women; 63%) presenting for new evaluation at a large tertiary care pain treatment center. Data were sourced primarily from an open-source, learning health system and pain registry and secondarily from manual review of electronic medical records. A binary opioid prescription variable (yes/no) constituted the dependent variable; independent variables were age, sex, pain intensity, pain catastrophizing, depression, and anxiety.

RESULTS

Most patients were prescribed at least one opioid medication (57%; n = 1,020). A significant interaction and main effects of pain intensity and pain catastrophizing on opioid prescription were noted (P < 0.04). Additive modeling revealed sex differences in the relationship between pain catastrophizing, pain intensity, and opioid prescription, such that opioid prescription became more common at lower levels of pain catastrophizing for women than for men.

CONCLUSIONS

Results supported the conclusion that pain catastrophizing and sex moderate the relationship between pain intensity and opioid prescription. Although men and women patients had similar Pain Catastrophizing Scale scores, historically "subthreshold" levels of pain catastrophizing were significantly associated with opioid prescription only for women patients. These findings suggest that pain intensity and catastrophizing contribute to different patterns of opioid prescription for men and women patients, highlighting a potential need for examination and intervention in future studies.

Duloxetine and Subacute Pain after Knee Arthroplasty when Added to a Multimodal Analgesic Regimen: A Randomized, Placebo-controlled, Triple-blinded Trial

BACKGROUND

Duloxetine is effective for chronic musculoskeletal and neuropathic pain, but there are insufficient data to recommend the use of antidepressants for postoperative pain. The authors hypothesized that administration of duloxetine for 15 days would reduce pain with ambulation at 2 weeks after total knee arthroplasty.

METHODS

In this triple-blinded, randomized, placebo-controlled trial, patients received either duloxetine or placebo for 15 days, starting from the day of surgery. Patients also received a comprehensive multimodal analgesic regimen including neuraxial anesthesia, epidural analgesia, an adductor canal block, meloxicam, and oxycodone/acetaminophen as needed. The primary outcome was the pain score (0 to 10 numeric rating scale) with ambulation on postoperative day 14.

RESULTS

One hundred six patients were randomized and analyzed. On day 14, duloxetine had no effect on pain with ambulation; mean pain was 3.8 (SD, 2.3) for placebo versus 3.5 (SD, 2.1) for duloxetine (difference in means [95% CI], 0.4 [-0.5 to 1.2]; P = 0.386). Symptoms potentially attributable to duloxetine discontinuation at study drug completion (nausea, anxiety) occurred among nine patients (duloxetine) and five patients (placebo); this was not statistically significant (P = 0.247). Statistically significant secondary outcomes included opioid consumption (difference in mean milligram oral morphine equivalents [95% CI], 8.7 [3.3 to 14.1], P = 0.002 by generalized estimating equation) over the postoperative period and nausea on day 1 (P = 0.040). There was no difference in other side effects or in anxiety and depression scores.

CONCLUSIONS

When included as a part of a multimodal analgesic regimen for knee arthroplasty, duloxetine does not reduce subacute pain with ambulation.

Preliminary validation of the Michigan Body Map

We developed the Michigan Body Map (MBM) as a self-report measure to assess body areas where chronic pain is experienced and to specifically quantify the degree of widespread body pain when assessing for centralized pain features (eg, fibromyalgia-like presentation). A total of 402 patients completed the measure in 5 distinct studies to support the validation of the original and a revised version of the MBM. Administration is rapid 39 to 44 seconds, and errors for the original MBM were detected in only 7.2% of the possible body areas. Most errors underestimated the number of painful areas or represented confusion in determining the right vs left side. The MBM was preferred (P = 0.013) and felt to better depict pain location (P = 0.001) when compared with the Widespread Pain Index checklist of the 2011 Fibromyalgia Survey Criteria, but participants did not express any preference between the MBM and Brief Pain Inventory body map. Based on the data from the first 3 studies, a revised version of the MBM was created including a front and back body image and improved guidance on right-sidedness vs left. The revised MBM was preferred when compared with the original and was more accurate in depicting painful body areas (P = 0.004). Furthermore, the revised MBM showed convergent and discriminant validity with other self-report measures of pain, mood, and function. In conclusion, the MBM demonstrated utility, reliability, and construct validity. This new measure can be used to accurately assess the distribution of pain or widespread bodily pain as an element of the fibromyalgia survey score.

Rethinking chronic pain in a primary care setting

Chronic pain substantially impacts patient function and quality of life and is a burden to society at large in terms of increased health care utilization and loss of productivity. As a result, there is an increasing recognition of chronic pain as a public health crisis. However, there remains wide variability in clinical practices related to the prevention, assessment, and treatment of chronic pain. Certain fundamental aspects of chronic pain are often neglected including the contribution of the psychological, social, and contextual factors associated with chronic pain. Also commonly overlooked is the importance of understanding the likely neurobiological mechanism(s) of the presenting pain and how they can guide treatment selection. Finally, physicians may not recognize the value of using electronic medical records to systematically capture data on pain and its impact on mood, function, and sleep. Such data can be used to monitor onset and maintenance of treatments effects at the patient level and evaluate costs at the systems level. In this review we explain how these factors play a critical role in the development of a coordinated, evidence-based treatment approach tailored to meet specific needs of the patient. We also discuss some practical approaches and techniques that can be implemented by clinicians in order to enhance the assessment and management of individuals with chronic pain in primary care settings.

Somatic Awareness and Tender Points in a Community Sample

Somatic awareness (SA) refers to heightened sensitivity to a variety of physical sensations and symptoms. Few attempts have been made to dissociate the relationship of SA and affective symptoms with pain outcomes. We used a validated measure of mood and anxiety symptoms that includes questions related to SA to predict the number of tender points found on physical examination in a large cross-sectional community sample (the Midlife in the United States [MIDUS] Biomarker study). General distress, positive affect, and SA, which were all significantly associated with tender point number in bivariate analyses, were used as predictors of the number of tender points in a multivariate negative binomial regression model. In this model a greater number of tender points was associated with higher levels of SA (P = .02) but not general distress (P = .13) or positive affect (P = .50). Follow-up mediation analyses indicated that the relationship between general distress and tender points was partially mediated by levels of SA. Our primary finding was that SA is strongly related to the number of tender points in a community sample. Mechanisms linking SA to the spatial distribution of pain sensitivity should be investigated further.

PERSPECTIVE

This article presents an analysis of 3 overlapping psychological constructs and their relationship to widespread pain sensitivity on palpation. The findings suggest that SA is most strongly related to the spatial distribution of pain sensitivity and that further assessing it may improve our understanding of the relationship between psychological factors and pain.

Perioperative management in children with chronic pain

Children with chronic pain often undergo surgery and effective perioperative management of their pain can be challenging. Identification of the pediatric chronic pain patient preoperatively and development of a perioperative pain plan may help ensure a safer and more comfortable perioperative course. Successful management usually requires multiple different classes of analgesics, regional anesthesia, and adjunctive nonpharmacological therapies. Neuropathic and oncological pain can be especially difficult to treat and usually requires an individualized approach.

Neurobiology of fibromyalgia and chronic widespread pain

Fibromyalgia is the current term for chronic widespread musculoskeletal pain for which no alternative cause can be identified. The underlying mechanisms, in both human and animal studies, for the continued pain in individuals with fibromyalgia will be explored in this review. There is a substantial amount of support for alterations of central nervous system nociceptive processing in people with fibromyalgia, and that psychological factors such as stress can enhance the pain experience. Emerging evidence has begun exploring other potential mechanisms including a peripheral nervous system component to the generation of pain and the role of systemic inflammation. We will explore the data and neurobiology related to the role of the CNS in nociceptive processing, followed by a short review of studies examining potential peripheral nervous system changes and cytokine involvement. We will not only explore the data from human subjects with fibromyalgia but will relate this to findings from animal models of fibromyalgia. We conclude that fibromyalgia and related disorders are heterogenous conditions with a complicated pathobiology with patients falling along a continuum with one end a purely peripherally driven painful condition and the other end of the continuum is when pain is purely centrally driven.

Opioid Use in Fibromyalgia: A Cautionary Tale

Multiple pharmacotherapies are available for the treatment of fibromyalgia (FM), including opioid analgesics. We postulate that the mechanism of action of traditional opioids predicts their lack of efficacy in FM. Literature searches of the MEDLINE and Cochrane Library databases were conducted using the search term opioid AND fibromyalgia to identify relevant articles, with no date limitations set. Citation lists in returned articles and personal archives of references were also examined for additional relevant items, and articles were selected based on the expert opinions of the authors. We found no evidence from clinical trials that opioids are effective for the treatment of FM. Observational studies have found that patients with FM receiving opioids have poorer outcomes than patients receiving nonopioids, and FM guidelines recommend against the use of opioid analgesics. Despite this, and despite the availability of alternative Food and Drug Administration-approved pharmacotherapies and the efficacy of nonpharmacologic therapies, opioids are commonly used in the treatment of FM. Factors associated with opioid use include female sex; geographic variation; psychological factors; a history of opioid use, misuse, or abuse; and patient or physician preference. The long-term use of opioid analgesics is of particular concern in the United States given the ongoing public health emergency relating to excess prescription opioid consumption. The continued use of opioids to treat FM despite a proven lack of efficacy, lack of support from treatment guidelines, and the availability of approved pharmacotherapy options provides a cautionary tale for their use in other chronic pain conditions.

Laparoscopic Cholecystectomy for Gallbladder Calculosis in Fibromyalgia Patients: Impact on Musculoskeletal Pain, Somatic Hyperalgesia and Central Sensitization

Fibromyalgia, a chronic syndrome of diffuse musculoskeletal pain and somatic hyperalgesia from central sensitization, is very often comorbid with visceral pain conditions. In fibromyalgia patients with gallbladder calculosis, this study assessed the short and long-term impact of laparoscopic cholecystectomy on fibromyalgia pain symptoms. Fibromyalgia pain (VAS scale) and pain thresholds in tender points and control areas (skin, subcutis and muscle) were evaluated 1week before (basis) and 1week, 1,3,6 and 12months after laparoscopic cholecystectomy in fibromyalgia patients with symptomatic calculosis (n = 31) vs calculosis patients without fibromyalgia (n. 26) and at comparable time points in fibromyalgia patients not undergoing cholecystectomy, with symptomatic (n = 27) and asymptomatic (n = 28) calculosis, and no calculosis (n = 30). At basis, fibromyalgia+symptomatic calculosis patients presented a significant linear correlation between the number of previously experienced biliary colics and fibromyalgia pain (direct) and muscle thresholds (inverse)(p<0.0001). After cholecystectomy, fibromyalgia pain significantly increased and all thresholds significantly decreased at 1week and 1month (1-way ANOVA, p<0.01-p<0.001), the decrease in muscle thresholds correlating linearly with the peak postoperative pain at surgery site (p<0.003-p<0.0001). Fibromyalgia pain and thresholds returned to preoperative values at 3months, then pain significantly decreased and thresholds significantly increased at 6 and 12months (p<0.05-p<0.0001). Over the same 12-month period: in non-fibromyalgia patients undergoing cholecystectomy thresholds did not change; in all other fibromyalgia groups not undergoing cholecystectomy fibromyalgia pain and thresholds remained stable, except in fibromyalgia+symptomatic calculosis at 12months when pain significantly increased and muscle thresholds significantly decreased (p<0.05-p<0.0001). The results of the study show that biliary colics from gallbladder calculosis represent an exacerbating factor for fibromyalgia symptoms and that laparoscopic cholecystectomy produces only a transitory worsening of these symptoms, largely compensated by the long-term improvement/desensitization due to gallbladder removal. This study provides new insights into the role of visceral pain comorbidities and the effects of their treatment on fibromyalgia pain/hypersensitivity.

Medical Cannabis Use Is Associated With Decreased Opiate Medication Use in a Retrospective Cross-Sectional Survey of Patients With Chronic Pain

Opioids are commonly used to treat patients with chronic pain (CP), though there is little evidence that they are effective for long term CP treatment. Previous studies reported strong associations between passage of medical cannabis laws and decrease in opioid overdose statewide. Our aim was to examine whether using medical cannabis for CP changed individual patterns of opioid use. Using an online questionnaire, we conducted a cross-sectional retrospective survey of 244 medical cannabis patients with CP who patronized a medical cannabis dispensary in Michigan between November 2013 and February 2015. Data collected included demographic information, changes in opioid use, quality of life, medication classes used, and medication side effects before and after initiation of cannabis usage. Among study participants, medical cannabis use was associated with a 64% decrease in opioid use (n = 118), decreased number and side effects of medications, and an improved quality of life (45%). This study suggests that many CP patients are essentially substituting medical cannabis for opioids and other medications for CP treatment, and finding the benefit and side effect profile of cannabis to be greater than these other classes of medications. More research is needed to validate this finding.

PERSPECTIVE

This article suggests that using medical cannabis for CP treatment may benefit some CP patients. The reported improvement in quality of life, better side effect profile, and decreased opioid use should be confirmed by rigorous, longitudinal studies that also assess how CP patients use medical cannabis for pain management.