Targeted muscle reinnervation at the time of amputation to prevent the development of neuropathic pain.

INTRODUCTION: Targeted muscle reinnervation (TMR) is an established modality for the surgical management of neuropathic pain. Although the preventive effect of primary (acute) TMR at the time of amputation has been demonstrated previously, it remains unclear how many and which patients benefit most. Therefore, this study investigated the proportion of patients achieving sustained pain prophylaxis following amputation, as well as factors associated with its efficacy. METHODS: Primary patients who underwent TMR with a minimum follow-up of 6 months between 2018 and 2023 were enrolled. Pain outcomes (numeric rating scale [NRS], 0-10), comorbidities, and surgical factors were collected from chart review. Patients achieving sustained pain prophylaxis (NRS of ≤3 for ≥3 months until final follow-up) were identified. Multilevel mixed-effect models and multivariable regression were used to visualize pain courses and identify associated factors. RESULTS: Seventy-five patients who underwent primary TMR were included (median follow-up: 2.0 years), of whom 57.3% achieved sustained pain prophylaxis whereas 26.7% reported pain disappearance. Distal amputation levels (p = 0.036), a lower Elixhauser Comorbidity Index (p = 0.001), and the absence of psychiatric comorbidities (p = 0.039) were associated with pain prophylaxis. CONCLUSION: This study demonstrates that more than half of all patients undergoing primary TMR achieved sustained pain prophylaxis, and approximately a quarter of patients achieved sustained pain disappearance. Several factors associated with these favorable outcomes are described. These results will aid in preoperative counseling, managing patient expectations, and selecting patients who may benefit most from primary TMR surgery. LEVEL OF EVIDENCE: IV - Therapeutic.

The Interrelationships Between Cognitive Biases for Pain: An Experimental Study.

Contemporary pain models highlight cognitive-processing biases (ie, attention bias [AB], interpretation bias [IB], and memory bias [MB]) as key processes that contribute to poor pain outcomes. However, existing research has yielded inconsistent findings regarding the presence and impact of these biases on pain outcomes. Recognizing the need to explore these biases simultaneously, contemporary pain models suggest that cognitive biases (CBs) are interrelated, and may have a combined impact upon pain problems. The current study aims to investigate the interrelationships between CBs using the PainAIM paradigm, a novel approach enabling simultaneous evaluation of pain-related AB, IB, and MB using cues signaling actual pain rather than symbolic information. We hypothesized the presence and positive associations of biases for pain-related cues and the predictive value of combined AB and IB for poor pain outcomes. Eighty-four healthy participants completed the PainAIM paradigm, followed by a cold pressor task probing pain experience and pain-related task interference. The results indicated an inverse relationship between AB and IB for ambiguous pain cues. In addition, there was a positive association between participants' AB for ambiguous pain and their MB for the same cues. Contrary to our hypotheses, CB indices did not predict experimental pain outcomes. These findings provide support for the interrelationships between pain-related CBs. However, future research on the temporal order of CBs and their combined impact on pain outcomes is needed. By overcoming the limitations associated with traditional paradigms, the PainAIM paradigm offers a promising research tool for the further study of combined CBs in the context of pain. PERSPECTIVE: The current study provides insight into the associations between pain-related CBs (AB, IB, and MB) using ecologically valid (ambiguous) pain cues. The results indicated an inverse association between pain-related AB and IB, while a positive association was found between AB and MB. CBs did however not predict experimental pain outcomes.

Cost-effectiveness of the Perioperative Pain Management Bundle a registry-based study.

Introduction: The Perioperative Pain Management Bundle was introduced in 10 Serbian PAIN OUT network hospitals to improve the quality of postoperative pain management. The Bundle consists of 4 elements: informing patients about postoperative pain treatment options; administering a full daily dose of 1-2 non-opioid analgesics; administering regional blocks and/or surgical wound infiltration; and assessing pain after surgery. In this study, we aimed to assess the cost-effectiveness of the Bundle during the initial 24 h after surgery. Materials and methods: The assessment of cost-effectiveness was carried out by comparing patients before and after Bundle implementation and by comparing patients who received all Bundle elements to those with no Bundle element. Costs of postoperative pain management included costs of the analgesic medications, costs of labor for administering these medications, and related disposable materials. A multidimensional Pain Composite Score (PCS), the effectiveness measurement, was obtained by averaging variables from the International Pain Outcomes questionnaire evaluating pain intensity, interference of pain with activities and emotions, and side effects of analgesic medications. The incremental cost-effectiveness ratio (ICER) was calculated as the incremental change in costs divided by the incremental change in PCS and plotted on the cost-effectiveness plane along with the economic preference analysis. Results: The ICER value calculated when comparing patients before and after Bundle implementation was 181.89 RSD (1.55 EUR) with plotted ICERs located in the northeast and southeast quadrants of the cost-effectiveness plane. However, when comparing patients with no Bundle elements and those with all four Bundle elements, the calculated ICER was -800.63 RSD (-6.82 EUR) with plotted ICERs located in the southeast quadrant of the cost-effectiveness plane. ICER values differ across surgical disciplines. Conclusion: The proposed perioperative pain management Bundle is cost-effective. The cost-effectiveness varies depending on the number of implemented Bundle elements and fluctuates across surgical disciplines.

Older Adults' Pain Outcomes After mHealth Interventions: Scoping Review.

BACKGROUND: Pain is prevalent and poorly managed in older adults. Although pain self-management strategies are helpful, adoption and access are limited; thus, technology provides an opportunity for intervention delivery. Mobile health (mHealth) is feasible to use in older adults; however, we have yet to understand the effect of mHealth pain self-management interventions on pain outcomes in older adults. OBJECTIVE: The purpose of this scoping review is to examine the characteristics of mHealth interventions and their efficacy on pain outcomes in older adults with musculoskeletal pain. METHODS: With the assistance of a medical librarian, keywords and subject headings were generated, including but not limited to mobile health application, mHealth, digital, pain, pain management, and older. A search was conducted for papers in journal databases, including PubMed, Embase, CINAHL, Scopus, and IEEE Xplore, between 2000 and 2022. Papers were screened according to predetermined inclusion and exclusion criteria, and reference lists were reviewed for additional paper inclusion. Three authors appraised the methodology of papers independently, then collaboratively to synthesize the evidence. RESULTS: Six publications were included in the scoping review. The design and methodology ranged widely from pilot studies to a comparative effectiveness trial. Older participants in the studies reported a variety of musculoskeletal conditions. Delivery of the mHealth pain self-management interventions incorporated mobile devices, such as a smartphone or tablet. Most mHealth-delivered interventions were multicomponent and incorporated elements of in-person and telephone access to an interventionist. The findings suggested mHealth interventions may reduce pain intensity; however, pain interference and other pain-related conditions did not have a statistically significant reduction. CONCLUSIONS: Research that has explored mHealth for pain self-management is beginning to move beyond feasibility. The few experimental studies conducted in older adults are heterogeneous, and the interventions are mostly multicomponent. It is premature to conclude the interventions' significant effect on pain or pain-related symptoms. As technology continues to integrate into health care, more experimental research is warranted to examine the efficacy of mHealth interventions on a variety of pain outcomes in older adults.

Let's Get Physical! A Comprehensive Review of Pre- and Post-Surgical Interventions Targeting Physical Activity to Improve Pain and Functional Outcomes in Spine Surgery Patients.

The goal of this comprehensive review was to synthesize the recent literature on the efficacy of perioperative interventions targeting physical activity to improve pain and functional outcomes in spine surgery patients. Overall, research in this area does not yet permit definitive conclusions. Some evidence suggests that post-surgical interventions may yield more robust long-term outcomes than preoperative interventions, including large effect sizes for disability reduction, although there are no studies directly comparing these surgical approaches. Integrated treatment approaches that include psychosocial intervention components may supplement exercise programs by addressing fear avoidance behaviors that interfere with engagement in activity, thereby maximizing the short- and long-term benefits of exercise. Efforts should be made to test brief, efficient programs that maximize accessibility for surgical patients. Future work in this area should include both subjective and objective indices of physical activity as well as investigating both acute postoperative outcomes and long-term outcomes.

The association between self-efficacy on function and pain outcomes among patients with chronic low back pain managed using the McKenzie approach: a prospective cohort study.

INTRODUCTION: Self-efficacy is a determinant of function and pain outcomes in patients with chronic low back pain receiving physiotherapy. The McKenzie approach is an effective intervention for patients with back pain that may affect self-efficacy. Study aims were to determine if, among patients with back pain being managed by McKenzie-credentialed physiotherapists: intake self-efficacy is correlated with intake function and pain; intake self-efficacy is associated with changes in function and pain during treatment; self-efficacy improves during treatment; and improvements in self-efficacy during treatment are associated with improvements in function and pain at discharge. METHODS: Two-hundred-eighty-two subjects with chronic low back pain seen by McKenzie-credentialed clinicians provided data on self-efficacy, function and pain at intake and discharge. RESULTS: Self-efficacy was correlated with function and pain at intake; however, intake self-efficacy was not associated with function or pain outcomes. Self-efficacy increased during treatment. This increase was associated with improvements in function and pain at discharge. CONCLUSION: While intake self-efficacy was associated with function and pain when initiating physiotherapy, it did not result in improved treatment outcomes. Specific interventions may be necessary to improve self-efficacy. The increases in self-efficacy observed during treatment were associated with improvements in function and pain outcomes at discharge.

Are Prayer-Based Interventions Effective Pain Management Options? A Systematic Review and Meta-analysis of Randomized Controlled Trials.

This review examined the effects of private and communal participatory prayer on pain. Nine databases were searched. Six randomized controlled trials were included. For private prayer, medium to large effects emerged for 67% to 69% of between-group comparisons; participants in the prayer condition reported lower pain intensity (0.59 < d < 26.17; 4 studies) and higher pain tolerance (0.70 < d < 1.05; 1 study). Pre- to post-intervention comparisons yielded medium to large effects (0.76 < d < 1.67; 2 studies); pain intensity decreased. Although firm conclusions cannot be made because meta-analysis was based on only two studies, the analysis suggested prayer might reduce pain intensity (SMD = - 2.63, 95% CI [- 3.11, - 2.14], I = 0%). (PROSPERO: CRD42020221733).

Definitions of Chronic Low Back Pain From a Scoping Review, and Analyses of Narratives and Self-Reported Health of Adults With Low Back Pain.

Among those with low back pain (LBP), individuals with chronic LBP (CLBP) face different treatment recommendations and incur the majority of suffering and costs. However, the way CLBP has been defined varies greatly. This study used a scoping review and qualitative and quantitative analyses of data from LBP patients to explore this variation. CLBP in most recent randomized controlled trials (RCTs) was defined by duration of pain, most commonly ≥3 months. However, individuals with LBP most often define CLBP by frequency. CLBP has also been defined using a combination of duration and frequency (16% of RCTs and 20% of individuals), including 6% of recent RCTs that followed the NIH Pain Consortium research task force (RTF) definition. Although not a defining characteristic of CLBP for individuals, almost 15% of recent RCTs required CLBP to have a healthcare provider diagnosis. In our LBP sample moving from ≥3 months to the RTF definition reduced the CLBP group size by 25% and resulted in a group that used more pain management options and reported worse health across all outcome measures. A pain duration definition offers ease of application. However, refinements to this definition (eg, RTF) can identify those who may be better intervention targets. PERSPECTIVE: This article presents the definitions used for CLBP by researchers and individuals, and the impact of these definitions on pain management and health outcomes. This information may help researchers choose better study inclusion criteria and clinicians to better understand their patients' beliefs about CLBP.

Bipolar Sealers and Tourniquet Use Have Similar Outcomes in Total Knee Arthroplasty.

Introduction: The use of tourniquets and bipolar sealers are effective methods of hemostasis during total knee arthroplasty (TKA). However, their effect on perioperative patient outcomes is unknown. The purpose of this study is to compare the efficacy of tourniquet-less, tourniquet-less with use of a bipolar sealer, and tourniquet use on postoperative pain and surgical outcomes following TKA. Methods: A retrospective study of prospectively collected data of 120 primary TKA cases was conducted at an urban academic hospital. Primary outcomes were visual analog scale (VAS) scores and opioid consumption (in morphine milligram equivalents). Demographics, length of stay (LOS), perioperative complications, and change in Knee Injury and Osteoarthritis Outcome Score (ΔKOOS) were also collected. Patients were divided into cohorts based on the use of tourniquet-less with bipolar sealer (TRLB) (n = 40), tourniquet (TR) (n = 40), or tourniquet-less (TRL) (n = 40). Results: There were no differences in demographic data between each cohort. TRLB, TR and TRL had similar LOS (2.68 ± 1.63 vs 2.29 ± 1.27 vs 2.36 ± 1.42 days; p = 0.472) and VAS pain score on postoperative day 1 (4.68 vs 3.74 vs 3.63; p = 0.209). There were also no differences in opioid consumption at 2 weeks (p = 0.903), 1 month (p = 0.973), 3 months (p = 0.983), or 5 months (p = 0.983) post-operatively. TRLB and TR had comparable improvement in ΔKOOS from baseline to 12 weeks post-operatively (Δ16.58 ± 8.47 vs Δ23.92 ± 14.60; p = 0.254). Compared to the ΔKOOS of TRL (Δ5.19 ± 2.59), TRLB and TR had clinically and statistically greater ΔKOOS improvements (p = 0.009; p = 0.001). The TRL cohort also had a higher readmission rate than TRLB and TR (15% vs 0% vs 5%, p = 0.025). Conclusion: Our findings demonstrate that both bipolar sealer and tourniquet use in TKA are associated with similar postoperative pain levels and LOS in comparison to tourniquet-less only TKA. However, bipolar sealer and tourniquet use may lead to better longer term improvement such as greater PRO score improvement and fewer readmissions.

Negative impact of chronic pain: The role of locus of control and perceived family validation of chronic pain.

The present study investigates how participants' locus of control and their family and friends' validation of their pain influences participants' chronic pain experiences. Four thousand, 25 adults were recruited through the Chronic Pain In America survey. Results show that individuals who endorse an internal locus of control and experience family and friends' validation of their chronic pain reported better chronic pain outcomes and less negative life impact due to chronic pain. The current results indicate the locus of control and family and friends' validation of chronic pain experience plays an important role in chronic pain and the impact of chronic pain across the life course.

Comparing Patient-Reported Outcomes in Patients Undergoing Lumbar Fusion for Isthmic Spondylolisthesis with Predominant Back Pain versus Predominant Leg Pain Symptoms.

OBJECTIVE: To compare patient-reported outcome measures (PROMs) and minimum clinically important difference (MCID) achievement following anterior or transforaminal lumbar interbody fusion for isthmic spondylolisthesis in patients presenting with predominant back pain versus predominant leg pain symptoms. METHODS: A single-surgeon database was reviewed for anterior or transforaminal lumbar interbody fusion procedures for isthmic spondylolisthesis. Patient demographics, perioperative characteristics, postoperative complications, and PROMs were collected. Demographic/perioperative characteristics were compared among groups using χ2 and Student t tests for categorical and continuous variables, respectively. Mean PROM scores were compared using an unpaired Student t test. Postoperative improvement from preoperative baseline within each cohort was assessed with paired-samples t test. MCID achievement rates were compared with χ2 analysis. RESULTS: In total, 143 patients were included with 65 patients in the predominant back pain and 78 patients in the predominant leg pain cohort. Preoperative visual analog scale (VAS) leg was noted to be significantly greater in predominant leg pain cohort (P < 0.001). Cohorts demonstrated significant mean postoperative differences for the following PROMs at the following postoperative time points: significant differences were noted between cohorts for rate of achievement of MCID for the following PROMs at the following time points: VAS back at 2 years and VAS leg at 6 weeks/12 weeks/6 months/overall (P < 0.036, all). CONCLUSIONS: Compared with patients presenting for surgery with predominant leg pain symptoms, patients undergoing lumbar fusion at L4-L5 and L5-S1 for isthmic spondylolisthesis with predominant back pain symptoms may demonstrate improved long-term clinical outcomes for reported back pain, leg pain, and disability and reduced postoperative length of stay and narcotic consumption.

Machine Learning and Pain Outcomes.

Machine learning (ML) is an increasingly popular method of data analysis that has meaningful application within the realm of pain management. Current research has used this technique as a tool to refine patient selection for more invasive pain management treatments in an effort to improve outcomes. It is also being used to aid in the search for biomarkers that could objectify the quantification of pain to better assess these outcomes. This article provides an overview of ML and its applications within the pain field.

Risk Stratification and Pain Outcomes Following Revision Total Hip Arthroplasty for Adverse Local Tissue Reactions.

BACKGROUND: Revision total hip arthroplasty (THA) for adverse local tissue reactions (ALTRs) secondary to head-neck taper corrosion is associated with a high complication rate. Diagnosis of ALTR is based on risk stratification using the patient's history and examination, implant risk, serum metal ion levels, and imaging. The purpose of this study was to determine if stratification using similar risk factors is predictive of outcomes following revision THA for metal-on-polyethylene (MoP) ALTR. METHODS: We performed a retrospective review on 141 patients revised for ALTR due to head-neck taper corrosion. Pain outcomes following surgery were analyzed using a generalized linear mixed model. Complications were defined as instability/dislocation, infection, fracture, nerve palsy, leg-length discrepancy, or reoperation. RESULTS: The overall complication rate was 17.7%. The odds of having pain decreased by 44% after revision surgery (Odds Ratio = 0.56, 95% Confidence Interval: 0.324 to 0.952). There was no significant difference in instability/dislocation based on either increased or decreased head-neck offset (P = .67) or magnetic resonance imaging findings of abductor loss, effusion size, and degree of ALTR (P = .73). Increased serum cobalt (P = .31) and chromium (P = .08) levels did not predict complications; however, a decreased cobalt-chromium ratio was associated with postoperative complications (2.8 versus 3.5; P = .002). CONCLUSION: These findings are the first to suggest that patients who have ALTR after MoP THA undergoing revision surgery demonstrated major pain relief. Increasing femoral head offset did not change rates of instability/dislocation. In clinical scenarios where preoperative cobalt-chromium femoral head offsets were greater than available ceramic head offsets, a mandatory decrease in femoral head offset did not increase rates of instability/dislocation.

A Single-Center Retrospective Analysis Investigating the Effect of Timing of Vertebral Augmentation on Pain Outcomes.

BACKGROUND: Approximately 700,000 individuals experience osteoporotic vertebral compression fractures (OVCF) every year in the United States. Chronic complications from patients and increasing economic burdens continue to be major problems with OVCFs. Multiple treatment options for OVCF are available, including conservative management, surgical intervention, and minimally invasive vertebral augmentation. Prior studies have investigated the utility of vertebral augmentation techniques such as percutaneous vertebroplasty (PVP), balloon vertebroplasty (BVP), and vertebral augmentation with the KivaTM implant on patient mortality with favorable results. The optimal time from OVCF occurrence to vertebral augmentation continues to be a topic of investigation. OBJECTIVES: To further investigate the effect of the timing of vertebral augmentation on pain outcomes. STUDY DESIGN: A retrospective cohort chart review study. SETTING: A single academic center in Albuquerque, New Mexico. METHODS: One hundred twenty-six consecutive patient encounters with OVCF diagnosed on imaging and treated with PVP, BVP, or vertebral augmentation with a KivaTM implant between 01/01/2004 and 11/28/2016 were analyzed. The time between fracture and intervention was categorized into < 6 weeks, 6-12 weeks, and >= 12 weeks. Pain scores were measured before and after treatment using the numeric pain rating scale. Statistical analysis using Wilcoxon-Mann-Whitney and Kruskal-Wallis tests were used as appropriate, and effect sizes were described with the Hodges-Lehmann estimates of difference. RESULTS: The 3 vertebral augmentation procedures compared in this study did not demonstrate statistically significant differences in pain score reduction (P = 0.949). The < 12 weeks group had a median and interquartile range (IQR) pain improvement of 3 (IQR 1,6) versus 1 (IQR 0,4) in the >= 12 weeks group (P = 0.018). Further analysis showed that the median and IQR pain improvement for the < 6 weeks group was 3 (IQR 1,7), for the 6-12 weeks group was 3 (IQR 1,4), and for the >= 12 weeks group was 1 (IQR 0,4). The overall effect of the time category on pain improvement was statistically significant for these groups (P = 0.040). Comparisons between groups only showed differences between the < 6 weeks and >= 12 weeks groups (P = 0.013), with an estimated median difference of 2 (95% CI 0,3). There was no statistically significant relationship between fill percentage and pain relief (P = 0.291). LIMITATIONS: This is a retrospective cohort study from a single academic center with a limited sample size that lacked a control group and procedural blinding. There was also substantial heterogeneity among patients, fractures, operators, and techniques. Pain relief outcomes are subjective and can be biased by patients as well as physician reporting. CONCLUSIONS: Early intervention (< 12 weeks) with vertebral augmentation in patients with OVCF is associated with improved pain scores when compared to later intervention (> 12 weeks). Very early intervention (< 6 weeks) confers a greater advantage when compared to later intervention (> 12 weeks).

Defining minimal clinically important differences in pain and disability outcomes of patients with chronic pain treated with spinal cord stimulation.

OBJECTIVE: Minimal clinically important difference (MCID) thresholds for a limited number of outcome metrics were previously defined for patients with failed back surgery syndrome (FBSS) at 6 months after spinal cord stimulation (SCS). This study aimed to further define MCID values for pain and disability outcomes. Additionally, the authors established 1-year MCID values for outcome measures with previously defined metrics commonly used to assess SCS efficacy. METHODS: Preoperative and 1-year postoperative outcomes were collected from 114 patients who received SCS therapy for FBSS, complex regional pain syndrome, and neuropathic pain. MCID values were established for the numerical rating scale (NRS), Oswestry Disability Index (ODI), Beck Depression Inventory (BDI), McGill Pain Questionnaire (MPQ), and Pain Catastrophizing Scale (PCS). Four established anchor-based methods were utilized to compute MCID values with two anchored questions: "Are you satisfied with SCS therapy?" and "Would you have SCS surgery again?" For each question, patients were categorized as responders if they answered "yes" or as nonresponders if they responded "no." The methodologies utilized to compute MCID scores included the average change method, minimum detectable change approach, change difference calculation, and receiver operating characteristic (ROC) analysis. Area under the ROC curve (AUC) analysis has been shown to inform the accuracy at which the MCID value can distinguish responders from nonresponders and was analyzed for each instrument. RESULTS: For the first time, ranges of MCID values after SCS were established for MPQ (1-2.3) and PCS (1.9-13.6). One-year MCID values were defined for all indications: NRS (range 0.9-2.7), ODI (3.5-6.9), and BDI (2-5.9). AUC values were significant for NRS (0.78, p < 0.001), ODI (0.71, p = 0.003), MPQ (0.74, p < 0.001), and PCS (0.77, p < 0.001), indicating notable accuracy for distinguishing satisfied patients. CONCLUSIONS: This was the first study to successfully determine MCID values for two prominent instruments, MPQ and PCS, used to assess pain after SCS surgery. Additionally, previously established MCID values for ODI, BDI, and the visual analog scale for patients with FBSS at 6 months after treatment were explored at 12 months for the most common indications for SCS. These data may better inform physicians of patient response to and success with SCS therapy.

The factor structure and subscale properties of the pain catastrophizing scale: are there differences in the distinctions?

Increasingly, studies have documented the negative impact of pain catastrophizing on health outcomes. The Pain Catastrophizing Scale (PCS) has been the measure of choice for many of these studies. The PCS provides 3 subscales for measuring pain catastrophizing: rumination, magnification, and helplessness. Factor analytic investigations of these factors have been limited by the sample size and relevance, and results have been inconsistent. No study has directly estimated the added value of subscale scoring of the PCS compared with scoring it as a single measure. OBJECTIVE: The purpose of this study was to evaluate the dimensionality of PCS responses in a sample of patients with chronic pain (N = 8370). METHODS: Data were randomly halved, and results were cross-validated. Both traditional factor analysis and traditional factor analyses were conducted. RESULTS: Findings based on common factor analyses and on bifactor analyses supported the essential unidimensionality of PCS responses. In the bifactor analyses, the general factor accounted for 96% of the explained common variance in the modeling sample. After extracting the general factor, helplessness, magnification, and rumination subscales accounted for 7.0%, 0.0%, and 15%, respectively. CONCLUSION: The results do not necessarily disconfirm helplessness, magnification, and rumination as clinically meaningful theoretical distinctions. However, the PCS (at least as presently constructed) fails to discriminate these distinctions. Joint efforts in theory and measurement science could illuminate the role that posited "kinds" of pain catastrophizing play in individuals' pain experiences.

The Adaptation of Pain Assessment Tools from High-Income to Low- and Middle-Income Countries: Psychometric Properties of a Set of Chronic Pain Questionnaires in Mongolian and New Zealand Patient Samples.

OBJECTIVE: Chronic pain is a leading cause of disability in low- and middle-income countries; however, pain assessment tools have generally been developed and validated in high-income countries. This study examines the psychometric properties of a set of translated pain (and distress) questionnaires in Mongolia and documents the characteristics of people seeking treatment for chronic pain in Mongolia, compared with those in New Zealand, which is representative of high-income countries. DESIGN: Cross-sectional, observational. SETTING: Hospital-based pain treatment centers in New Zealand and Mongolia. SUBJECTS: People seeking treatment for chronic pain in Mongolia (N = 142) and New Zealand (N = 159). METHODS: The Brief Pain Inventory, the Depression Anxiety Stress Scale-21, the Pain Catastrophizing Scale, and the Pain Self-Efficacy Questionnaire were translated into Mongolian and administered to patients attending a hospital-based pain service. Questionnaires that were completed by patients in New Zealand were used for comparisons. Internal reliability, convergent validity, and factor structure were assessed in both groups. RESULTS: Patients in Mongolia were older and reported lower pain intensity, interference, and distress and higher pain self-efficacy than those in New Zealand. The translated questionnaires had good internal consistencies, and the relationships between pain variables were similar across both groups. The factor structure for the Pain Catastrophizing Scale was consistent across both groups, but this was not the case for the Brief Pain Inventory or the Depression Anxiety Stress Scale-21. CONCLUSIONS: Findings indicate that some pain outcome measures may be appropriate for use in Mongolia and should be investigated in other low- and middle-income countries.

A Systematic Review of the Association Between Perceived Injustice and Pain-Related Outcomes in Individuals with Musculoskeletal Pain.

OBJECTIVE: A growing body of literature shows that justice-related appraisals are significant determinants of pain-related outcomes and prolonged trajectories of recovery. We conducted a systematic review of the literature assessing the relationship between perceived injustice and pain-related outcomes in individuals with musculoskeletal pain. DESIGN AND PARTICIPANTS: A search of published studies in English in PubMed, PsychInfo, Embase, and Cochrane Database of Systematic Reviews from database inception through May 2019 was performed. Search terms included "perceived injustice," "injustice appraisals," "perceptions of injustice," and "pain" or "injury." RESULTS: Thirty-one studies met inclusion criteria. Data for a total of 5,969 patients with musculoskeletal pain were extracted. Twenty-three studies (71.9%) reported on individuals with persistent pain lasting over three months, and 17 studies (53.1%) reported on individuals with injury-related musculoskeletal pain. Significant associations were found between perceived injustice and pain intensity, disability and physical function, symptoms of depression and anxiety, post-traumatic stress disorder, quality of life and well-being, and quality of life and social functioning. CONCLUSIONS: This systematic review summarizes the current evidence for the association between perceived injustice and pain-related outcomes. There is strong evidence that perceived injustice is associated with pain intensity, disability-related variables, and mental health outcomes. Implications and directions for future research are discussed.

Pain and Psychological Outcomes Among Iraq and Afghanistan Veterans with Chronic Pain and PTSD: ESCAPE Trial Longitudinal Results.

OBJECTIVE: To compare pain and psychological outcomes in veterans with chronic musculoskeletal pain and comorbid post-traumatic stress disorder (PTSD) or pain alone and to determine if veterans with comorbidity respond differently to a stepped-care intervention than those with pain alone. DESIGN: Secondary analysis of data from the Evaluation of Stepped Care for Chronic Pain (ESCAPE) trial. SETTING: Six Veterans Health Affairs clinics. SUBJECTS: Iraq and Afghanistan veterans (N = 222) with chronic musculoskeletal pain. METHODS: Longitudinal analysis of veterans with chronic musculoskeletal pain and PTSD or pain alone and available baseline and nine-month trial data. Participants randomized to either usual care or a stepped-care intervention were analyzed. The pain-PTSD comorbidity group screened positive for PTSD and had a PTSD Checklist-Civilian score ≥41 at baseline. RESULTS: T tests demonstrated statistically significant differences and worse outcomes on pain severity, pain cognitions, and psychological outcomes in veterans with comorbid pain and PTSD compared with those with pain alone. Analysis of covariance (ANCOVA) modeling change scores from baseline to nine months indicated no statistically significant differences, controlling for PTSD, on pain severity, pain centrality, or pain self-efficacy. Significant differences emerged for pain catastrophizing (t = 3.10, P < 0.01), depression (t = 3.39, P < 0.001), and anxiety (t = 3.80, P < 0.001). The interaction between PTSD and the stepped-care intervention was not significant. CONCLUSIONS: Veterans with the pain-PTSD comorbidity demonstrated worse pain and psychological outcomes than those with chronic pain alone. These findings indicate a more intense chronic pain experience for veterans when PTSD co-occurs with pain. PTSD did not lead to a differential response to a stepped-care intervention.

Chronic Pain and Sleep Disturbances: A Pragmatic Review of Their Relationships, Comorbidities, and Treatments.

OBJECTIVE: The objective of this review is to answer three questions: 1) How are chronic pain severity and pain duration affected in patients with chronic pain and sleep disturbances that occur simultaneously? 2) What are common comorbidities and pain-related symptoms seen in patients with chronic pain and sleep disturbances? and 3) What are potentially effective pharmacological and nonpharmacological treatment options for both conditions? METHODS: Ovid Medline and PubMed were searched. Search terms included sleep wake disorder, chronic pain, fibromyalgia, treatment outcome, psychotherapy, complementary therapies, and therapeutics. Studies that assessed outcomes between individuals with chronic pain and those with concurrent chronic pain and sleep disturbances were included. Randomized controlled clinical trials of treatments for both conditions were included. RESULTS: Sixteen studies indicated that patients with both chronic pain and sleep disturbances have greater pain severity, longer duration of pain, greater disability, and are less physically active than those without sleep disturbances. Patients with both conditions are more likely to have concurrent depression, catastrophizing, anxiety, and suicidal ideation. Thirty-three randomized controlled trials assessed treatment for both chronic pain and sleep disturbances. Pregabalin was the most frequently studied medication, showing improvement in pain and sleep symptoms. Cognitive behavioral therapy for insomnia showed long-term improvement in sleep for patients with chronic pain. CONCLUSIONS: Individuals with chronic pain and sleep disturbances have greater symptom severity, longer duration of symptoms, more disability, and additional comorbidities. Pharmacological and nonpharmacological treatments may be useful in the treatment of concurrent chronic pain and sleep disturbances, but further study is needed.