Sex-based differences in pain distribution in a cohort of patients with persistent post-traumatic neck pain

The burden of neck pain in the Middle East and North Africa region, 1990-2019

Background

Neck pain is a common cause of disability across the world. The objective of the present study was to present a thorough investigation of the burden caused by neck pain in the Middle East and North Africa (MENA) region, by country, sex, age group and socio-demographic index (SDI).

Methods

The data on the burden of neck pain, encompassing its prevalence, incidence and years lived with disability (YLDs), were extracted from the Global Burden of Disease (GBD) 2019 study. These findings are reported as age-standardised numbers and rates (per 100,000), accompanied by 95 % uncertainty intervals (UIs).

Results

The age-standardised point prevalence of neck pain in 2019 was 3066.7 (95 % UI: 2407.8 to 3894.3) per 100,000, with an age-standardised incidence rate of 649.2 (509.2-829.2) in the MENA region, neither of which have changed since 1990. The age-standardised YLD rate of neck pain was 303.0 (201.5-438.8) per 100,000 population in 2019. The highest YLD rate of neck pain was found in Iran [423.5 (280.3-609.8)] and the lowest in Kuwait [215.0 (141.0-314.1)]. The highest number of prevalent cases were seen in the 45-49 age-group for both sexes in 2019, but overall females had a higher point prevalence than males. Furthermore, over the study period (1990-2019) there was no clear and consistent relationship between the SDI and the burden of neck pain.

Conclusion

Although the burden of neck pain has largely remained stable over the past three decades, the prevalence and morbidity in the MENA region remains high. Preventive and rehabilitative programs should be implemented that firstly target middle-aged females and males.

Pre-Trauma Pain Is the Strongest Predictor of Persistent Enhanced Pain Patterns after Severe Trauma: Results of a Single-Centre Retrospective Study

Background and Objectives: Traumatic injuries are a significant public health issue worldwide, with persistent enhanced pain being a common complication following severe trauma. Persistent and chronic pain can have a profound impact on patients' quality of life, affecting physical, emotional, and social functioning. This study aimed to investigate the pain patterns of trauma patients before and after severe trauma, and identify the predictors of persisting pain after injury. Materials and Methods: A total of 596 patients of a level-one trauma centre with severe trauma were included in this study. The Trauma Outcome Profile Scale was used to assess pain severity before and after trauma, and a logistic regression analysis was performed to determine the most significant predictors of relevant pain after severe trauma. Results: The mean age of the included patients was 48.2 years, and 72% were males. The most frequent cause of injury was traffic accidents, and the mean Injury Severity Score was 17.6. Nearly half of the patients experienced reduced pain-related quality of life after trauma, with persisting pain predominantly occurring in the neck, spine, shoulder, pelvis, hip, knee, and feet. Even minor injuries led to increased pain scores. Preexisting pain before injury (OR: 5.43; CI: 2.60-11.34), older age (OR: 2.09, CI: 1.22-3.27), female gender (OR: 1.08, CI: 0.73-1.59), and high injury severity (OR: 1.80, CI: 1.20-2.69) were identified as significant predictors of enhanced pain. Conclusions: These findings highlight the importance of considering pre-existing pain, body area, and injury severity in assessing the risk of persistent pain in trauma patients.

A Brief Overview: Sex Differences in Prevalent Chronic Musculoskeletal Conditions

Musculoskeletal (MSK) pain disorders are some of the most prevalent and disabling chronic pain conditions worldwide. These chronic conditions have a considerable impact on the quality of life of individuals, families, communities, and healthcare systems. Unfortunately, the burden of MSK pain disorders does not fall equally across the sexes. Females consistently demonstrate more prevalent and severe clinical presentations of MSK disorders, and this disparity increases in magnitude with age. The aim of the present article is to review recent studies that have examined sex differences between males and females in four of the most common MSK pain disorders: neck pain, low back pain, osteoarthritis, and rheumatoid arthritis.

Exercise therapy for whiplash-associated disorders: a systematic review and meta-analysis

OBJECTIVES

Acute as well as chronic pain syndromes are common after whiplash trauma and exercise therapy is proposed as one possible intervention strategy. The aim of the present systematic review was to evaluate the effect of exercise therapy in patients with Whiplash-Associated Disorders for the improvement of neck pain and neck disability, compared with other therapeutic interventions, placebo interventions, no treatment, or waiting list.

CONTENT

The review was registered in Prospero (CRD42017060356) and conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A literature search in PubMed, Scopus and Cochrane from inception until January 13, 2020 was combined with a hand search to identify eligible randomized controlled studies. Abstract screening, full text assessment and risk of bias assessment (Cochrane RoB 2.0) were conducted by two independent reviewers.

SUMMARY

The search identified 4,103 articles. After removal of duplicates, screening of 2,921 abstracts and full text assessment of 100 articles, 27 articles that reported data for 2,127 patients were included. The included articles evaluated the effect of exercise therapy on neck pain, neck disability or other outcome measures and indicated some positive effects from exercise, but many studies lacked control groups not receiving active treatment. Studies on exercise that could be included in the random-effect meta-analysis showed significant short-term effects on neck pain and medium-term effects on neck disability.

OUTLOOK

Despite a large number of articles published in the area of exercise therapy and Whiplash-Associated Disorders, the current evidence base is weak. The results from the present review with meta-analysis suggests that exercise therapy may provide additional effect for improvement of neck pain and disability in patients with Whiplash-Associated Disorders.

The feasibility of gym-based exercise therapy for patients with persistent neck pain

Background and aims Persistent neck pain is common and can be detrimental to the health of those who are affected. This is particularly common after neck trauma, where it poses a challenge to health care providers. In this paper, we present the design and results of a study aimed primarily at assessing the feasibility of a supervised exercise intervention for patients with persistent neck pain after trauma. As a secondary aim, we analyzed the results of the intervention. Methods We designed and conducted a feasibility study using a mixed methods design. Ten patients with persistent neck pain (nine with a history of neck trauma and one with sudden onset of neck pain) were recruited from a specialized pain rehabilitation center and underwent a gym-based individual exercise therapy intervention, supervised by a physical therapist. We assessed the feasibility of the exercise therapy intervention based on the experiences of the patients and physical therapists. We analyzed both quantitative and qualitative results using descriptive statistics, content analysis, and questionnaires. Results The study found the exercise therapy to be a feasible alternative for patients with persistent neck pain. Most of the practical aspects of the intervention and study were executed as planned, and the study was well received by the patients, who found it a valuable part of their rehabilitation. In the quantitative analysis, improvements were observed on the Neck Disability Index, numerical rating scale for pain, EuroQol 5D, and physical activity, with scores on the Neck Disability Index showing a statistically significant improvement. Scores on the Disability Rating Index showed a non-significant deterioration. The qualitative analysis uncovered one overarching theme and four themes for the patients and three themes for the physical therapist. Conclusions The exercise therapy intervention seems to be feasible with favorable outcomes for the patients. The quantitative and qualitative analyses demonstrated exercise therapy to be beneficial from several different perspectives. However, although structured, the training needs customization and individual adaption from a clinical reasoning perspective in order to meet each patient's individual needs. Implications This study shows that supervised gym-based exercise therapy is feasible for patients with severe, persistent neck pain. It facilitates and motivates the execution of a larger, controlled trial, which might then lead to a new and potentially effective addition to the toolbox of all health care providers treating patients with persistent neck pain.

Outcomes of Interdisciplinary Pain Rehabilitation Across Subgroups of the Multidimensional Pain Inventory - A Study From the Swedish Quality Registry for Pain Rehabilitation

INTRODUCTION

The Multidimensional Pain Inventory (MPI) is frequently used in the assessment of chronic pain. Three subgroups have been derived from MPI: adaptive coper (AC), dysfunctional (DYS), and interpersonally distressed (ID). The primary aim of this study was to examine whether outcome of Interdisciplinary Multimodal Pain Rehabilitation Programs (IMMRPs) differed across the MPI subgroups.

METHODS

Patients with chronic pain (N = 34,513), included in the Swedish Quality Registry for Pain Rehabilitation, were classified into MPI subgroups and a subset that participated in IMMRPs (N = 13,419) was used to examine overall treatment outcomes using a previously established Multivariate Improvement Score (MIS) and 2 retrospective patient-evaluated benefits from treatment.

RESULTS

The subgroups differed on sociodemographic characteristics, pain duration, and spatial spreading of pain. DYS and ID had the best overall outcomes to MIS. AC had the best outcomes according to the 2 retrospective items. Transition into other subgroups following IMMRP was common and most prominent in DYS and least prominent in AC.

CONCLUSION

The validity of the MPI subgroups was partially confirmed. DYS and ID had the most severe clinical presentations at baseline and showed most improvement following IMMRP, but overall severity in DYS and ID at post-treatment was still higher than in the AC group. Future studies should examine how processes captured by MPI interact with neurobiological, medical, sociodemographic, and adaptation/coping factors and how these interactions impact severity of chronic pain and treatment outcome.

Spreading of Pain in Patients with Chronic Pain is Related to Pain Duration and Clinical Presentation and Weakly Associated with Outcomes of Interdisciplinary Pain Rehabilitation: A Cohort Study from the Swedish Quality Registry for Pain Rehabilitation (SQRP)

Introduction

The extent to which pain is distributed across the body (spreading of pain) differs largely among patients with chronic pain conditions and widespread pain has been linked to poor quality of life and work disability. A longer duration of pain is expected to be associated with more widespread pain, but studies are surprisingly scarce. Whether spreading of pain is associated with clinical presentation and treatment outcome in patients seen in interdisciplinary multimodal pain rehabilitation programs (IMMRPs) is unclear. The association between spreading of pain and (1) pain duration (2) clinical presentation (eg, pain intensity, pain-related cognitions, psychological distress, activity/participation aspects and quality of life) and (3) treatment outcome were examined.

Methods

Data from patients included in the Swedish Quality Registry for Pain Rehabilitation were used (n=39,916). A subset of patients that participated in IMMRPs (n=14,666) was used to examine whether spreading of pain at baseline predicted treatment outcome. Spreading of pain was registered using 36 predefined anatomical areas which were summarized and divided into four categories: 1–6 regions with pain (20.6% of patients), 7–12 regions (26.8%), 13–18 regions (22.0%) and 19–36 regions (30.6%).

Results

More widespread pain was associated with a longer pain duration and a more severe clinical picture at baseline with the strongest associations emerging in relation to health and pain aspects (pain intensity, pain interference and pain duration). Widespread pain was associated with a poorer overall treatment outcome following IMMRPs at both posttreatment and at a 12-month follow-up, but effect sizes were small.

Discussion

Spreading of pain is an indicator of the duration and severity of chronic pain and to a limited extent to outcomes of IMMRP. Longer pain duration in those with more widespread pain supports the concept of early intervention as clinically important and implies a need to develop and improve rehabilitation for patients with chronic widespread pain.

Healthy Pain-Free Individuals with a History of Distal Radius Fracture Demonstrate an Expanded Distribution of Experimental Referred Pain Toward the Wrist

OBJECTIVE

Nociception caused by injuries may sensitize central mechanisms causing expanded pain areas. After recovery, the status of such pain distribution and sensitivity mechanisms is unknown. The present study investigated whether individuals who have fully recovered from a distal radius fracture demonstrate increased pain sensitivity and expanded distribution of pressure-induced pain.

DESIGN

Cross-sectional single-blinded study.

SETTING

Clinical setting.

SUBJECTS

Twenty-three pain-free individuals with a history of painful distal radius fracture and 22 nonfractured, age/gender-matched controls participated in two experimental sessions (day 0, day 1) 24 hours apart.

METHODS

Pressure pain thresholds (PPTs) were recorded bilaterally at the extensor carpi radialis longus (ECRL), infraspinatus, and gastrocnemius muscles. Spatial distribution of pain was assessed following 60-second painful pressure stimulation at the ECRL (bilateral) and the infraspinatus muscles on the fractured or dominant side. Participants drew pain areas on a body map. After day 0 assessments, prolonged pain was induced by eccentric exercise of wrist extensors on the fractured/dominant side.

RESULTS

Compared with controls, pressure-induced ECRL pain in the fracture group referred more frequently toward the distal forearm (P < 0.005) on day 0. Both groups showed larger pain areas on day 1 compared with day 0 (P < 0.005), although the fracture group showed a larger relative change between days (P < 0.005). The fracture group showed larger pain areas on the fracture side compared with the contralateral side on both days (P < 0.005).

CONCLUSIONS

Prolonged pain and recovered prior painful injuries like fractures may sensitize pain mechanisms manifested as expanded pain distribution. Pressure-induced referred pain can be a simple pain biomarker for clinical use.

Pain and Evil: From Local Nociception to Misery Following Social Harm

Experiencing pain, especially when chronic, is an excruciating condition that should be regarded as a syndrome, if not a disease. People suffering from chronic pain tend to develop psychological discomfort mostly due to lack of acceptance, disbelief, blame. The complexity of pain pathophysiology, plus a wide range of negative psychosocial factors, leads to a more complex suffering that deserves attention and multidisciplinary treatments. The possibility that chronic pain may occur following physical aggression, torture, or persecution raises the issue of evil as a major contributor to pain in its worst representation - when individuals or groups are attacked based on racial, social, gender, religious, political, or other grounds. To explore the complex issue of chronic pain following physical or psychological harm, and to underscore the need for a multidisciplinary approach to reduce the burden of chronic pain, we discuss the biological mechanisms underlying pain state. We seek to clarify those factors leading to pain chronification, as well as personal and social attitudes that confound patients with chronic pain. The importance of family and social environment is also investigated, as well as personality traits of chronic pain patients that may further hamper successful treatment. The presence of chronic pain, modulated by, for example, acceptance of being a victim of premeditated physical and social violence, makes the issue more difficult to comprehend.

Diagnostic Accuracy of Videofluoroscopy for Symptomatic Cervical Spine Injury Following Whiplash Trauma

Background: Intervertebral instability is a relatively common finding among patients with chronic neck pain after whiplash trauma. Videofluoroscopy (VF) of the cervical spine is a potentially sensitive diagnostic tool for evaluating instability, as it offers the ability to examine relative intervertebral movement over time, and across the entire continuum of voluntary movement of the patient. At the present time, there are no studies of the diagnostic accuracy of VF for discriminating between injured and uninjured populations. Methods: Symptomatic (injured) study subjects were recruited from consecutive patients with chronic (>6 weeks) post-whiplash pain presenting to medical and chiropractic offices equipped with VF facilities. Asymptomatic (uninjured) volunteers were recruited from family and friends of patients. An ethical review and oversight were provided by the Spinal Injury Foundation, Broomfield, CO. Three statistical models were utilized to assess the sensitivity, specificity, positive and negative predictive values (PPV and NPV) of positive VF findings to correctly discriminate between injured and uninjured subjects. Results: A total of 196 subjects (119 injured, 77 uninjured) were included in the study. All three statistical models demonstrated high levels of sensitivity and specificity (i.e., receiver operating characteristic (ROC) values of 0.71 to 0.95), however, the model with the greatest practical clinical utility was based on the number of abnormal VF findings. For 2+ abnormal VF findings, the ROC was 0.88 (93% sensitivity, 79% specificity) and the PPV and NPV were both 88%. The highest PPV (1.0) was observed with 4+ abnormal findings. Conclusions: Videofluoroscopic examination of the cervical spine provides a high degree of diagnostic accuracy for the identification of vertebral instability in patients with chronic pain stemming from whiplash trauma.

Acceptance: a factor to consider in persistent pain after neck trauma

Background and aims

Studies on the interaction between acceptance and pain-related processes after neck trauma are to our knowledge sparse and such treatment strategies are rarely incorporated in management and treatment of posttraumatic neck pain. Thus, the aim of the present study is to investigate how acceptance relates to persistent pain in patients after neck trauma, when controlling for the influence of other psychological factors, trauma characteristics and demographic variables.

Methods

Consecutive patients with persistent pain and disability after neck trauma (n = 565) were assessed by a multi-professional team at a specialized pain rehabilitation clinic. Separate regression analyses were conducted with three outcomes: pain distribution, pain interference, and pain severity. Predictors were age, sex, education, time since trauma, type of trauma, anxiety, depression, and acceptance.

Results

Acceptance was the only factor associated with all outcomes, and patients with lower acceptance displayed more widespread pain and greater interference and severity of pain. The results also showed that higher depression was associated with worse pain interference and severity, whilst anxiety only mattered significantly for pain severity and not for pain interference. Female sex was related to more widespread pain and greater pain interference.

Conclusions

Overall acceptance stood out as the most important factor for the different outcomes and lower acceptance was associated with more widespread pain distribution and greater pain interference and severity.

Implications

The findings of this study add to a growing body of literature confirming that the development of chronicity after neck trauma should be understood as a multidimensional process, best described by a biopsychosocial model. The results also suggest that psychological factors and especially acceptance might be important processes with implications for enhanced recovery after neck trauma.

Spectroscopic differences in posterior insula in patients with chronic temporomandibular pain

Background and aims Chronic pain including temporomandibular disorder (TMD) pain involves a complex interplay between peripheral and central sensitization, endogenous modulatory pathways, cortical processing and integration and numerous psychological, behavioral and social factors. The aim of this study was to compare spectroscopic patterns of N-Acetyl-aspartate (NAA), total creatine (tCr), choline (Cho), myo-inositol (MI), glutamate (Glu), and the combination of Glu and glutamine in the posterior insula in patients with chronic generalized or regional chronic TMD pain (gTMD and rTMD, respectively) compared to healthy individuals (HI) in relation to clinical findings of TMD pain. Methods Thirty-six female patients with chronic rTMD or gTMD with at least 3 months duration were included in the study. Ten healthy women were included as controls. All participants completed a questionnaire that comprised assessment of degrees of depression, anxiety, stress, catastrophizing, pain intensity, disability and locations. A clinical Diagnostic Criteria for Temporomandibular Disorders examination that comprised assessment of pain locations, headache, mouth opening capacity, pain on mandibular movement, pain on palpation and temporomandibular joint noises was performed. Pressure-pain threshold (PPT) over the masseter muscle and temporal summation to pressure stimuli were assessed with an algometer. Within a week all participants underwent non-contrast enhanced MRI on a 3T MR scanner assessing T1-w and T2-w fluid attenuation inversion recovery. A single-voxel 1H-MRS examination using point-resolved spectroscopy was performed. The metabolite concentrations of NAA, tCr, Cho, MI, Glu and Glx were analyzed with the LC model. Metabolite levels were calculated as absolute concentrations, normalized to the water signal. Metabolite concentrations were used for statistical analysis from the LC model if the Cramér-Rao bounds were less than 20%. In addition, the ratios NAA/tCr, Cho/tCr, Glu/tCr and MI/tCr were calculated. Results The results showed significantly higher tCr levels within the posterior insula in patients with rTMD or gTMD pain than in HI (p=0.029). Cho was negatively correlated to maximum mouth opening capacity with or without pain (rs=-0.42, n=28, p=0.031 and rs=-0.48, n=28, p=0.034, respectively) as well as pressure-pain threshold on the hand (rs=-0.41, n=28, p=0.031). Glu was positively correlated to temporal summation to painful mechanical stimuli (rs=0.42, n=26, p=0.034). Conclusions The present study found that increased concentrations of Cho and Glu in the posterior insular cortex is related to clinical characteristics of chronic TMD pain, including generalized pain. These findings provide new evidence about the critical involvement of the posterior insular cortex and the neurobiology underlying TMD pain in both regional and generalized manifestations. Implications The findings in this study have indirect implications for the diagnosis and management of TMD patients. That said, the findings provide new evidence about the critical involvement of the posterior insular cortex and the neurobiology underlying TMD pain in both regional and generalized manifestations. It is also a further step towards understanding and accepting chronic pain as a disorder in itself.

Quantitative sensory testing response patterns to capsaicin- and ultraviolet-B-induced local skin hypersensitization in healthy subjects: a machine-learned analysis

The comprehensive assessment of pain-related human phenotypes requires combinations of nociceptive measures that produce complex high-dimensional data, posing challenges to bioinformatic analysis. In this study, we assessed established experimental models of heat hyperalgesia of the skin, consisting of local ultraviolet-B (UV-B) irradiation or capsaicin application, in 82 healthy subjects using a variety of noxious stimuli. We extended the original heat stimulation by applying cold and mechanical stimuli and assessing the hypersensitization effects with a clinically established quantitative sensory testing (QST) battery (German Research Network on Neuropathic Pain). This study provided a 246 × 10-sized data matrix (82 subjects assessed at baseline, following UV-B application, and following capsaicin application) with respect to 10 QST parameters, which we analyzed using machine-learning techniques. We observed statistically significant effects of the hypersensitization treatments in 9 different QST parameters. Supervised machine-learned analysis implemented as random forests followed by ABC analysis pointed to heat pain thresholds as the most relevantly affected QST parameter. However, decision tree analysis indicated that UV-B additionally modulated sensitivity to cold. Unsupervised machine-learning techniques, implemented as emergent self-organizing maps, hinted at subgroups responding to topical application of capsaicin. The distinction among subgroups was based on sensitivity to pressure pain, which could be attributed to sex differences, with women being more sensitive than men. Thus, while UV-B and capsaicin share a major component of heat pain sensitization, they differ in their effects on QST parameter patterns in healthy subjects, suggesting a lack of redundancy between these models.

Gender Differences in Pain Experience and Treatment after Motor Vehicle Collisions: A Secondary Analysis of the CRASH Injury Study

PURPOSE

Little is known about gender differences in the treatment of pain after motor vehicle collisions (MVCs) in an emergency department (ED). We aimed to describe gender differences in pain experiences and treatment, specifically the use of opioids and benzodiazepines after ED discharge, for MVC-related pain.

METHODS

This was a secondary analysis of previously collected data from the CRASH Injury studies. We included patients who were seen and discharged from an ED after an MVC and who were enrolled in 1 of 2 multicenter longitudinal prospective cohort studies (1 black/non-Hispanic and 1 white/non-Hispanic). First, we compared the experience of pain as defined by self-reported moderate-to-severe axial pain, widespread pain, number of somatic symptoms, pain catastrophizing, and peritraumatic distress between women and men using bivariate analyses. We then determined whether there were gender differences in the receipt of prescription medications for post-MVC pain symptoms (opioids and benzodiazepines) using multivariate logistic regression adjusting for demographic characteristics, pain, and collision characteristics.

FINDINGS

In total, 1878 patients were included: 61.4% were women. More women reported severe symptoms on the pain catastrophizing scale (36.8% vs 31.0%; P = 0.032) and peritraumatic distress following the MVC (59.7% vs 42.5%; P < 0.001), and women reported more somatic symptoms than men (median, 3.9; interquartile range, 3.7-4.0 vs median, 3.3; interquartile range, 3.1-3.5; P < 0.001). Unadjusted, similar proportions of women and men were given opioids (29.2% vs 29.7%; P = 0.84). After adjusting for covariates, women and men remained equally likely to receive a prescription for opioids (relative risk = 0.83; 95% confidence interval, 0.58-1.19). Women were less likely than men to receive a benzodiazepine at discharge from an ED (relative risk = 0.53; 95% confidence interval, 0.32-0.88).

IMPLICATIONS

In a large, multicenter study of ED patients treated for MVC, there were gender differences in the acute psychological response to MVC with women reporting more psychological and somatic symptoms. Women and men were equally likely to receive opioid prescriptions at discharge. Future research should investigate potential gender-specific interventions to reduce both posttraumatic distress and the risk of developing negative long-term outcomes like chronic pain.