Self-reported pain severity, quality of life, disability, anxiety and depression in patients classified with ‘nociceptive’, ‘peripheral neuropathic’ and ‘central sensitisation’ pain. The discriminant validity of mechanisms-based classifications of low back (±leg) pain

Pain interference, pain type, and quality of life among adults with spina bifida

INTRODUCTION

Individuals with spina bifida (SB) experience nociceptive and neuropathic pain, and women with SB report more pain. However, the relationship between pain type and gender on pain interference and quality of life (QoL) among individuals with SB is less understood.

OBJECTIVE

To assess relationships among pain interference, pain quality, participation-related QoL, and gender among adults with SB.

DESIGN

Fifty-one adults with SB completed a self-report survey assessing SB characteristics, pain severity, pain type, pain interference, and QoL.

SETTING

Hospital outpatient adult SB clinic.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Measures of nociceptive pain quality, neuropathic pain quality, participation-related QoL, as well as pain interference with general activities, mood, and sleep were selected a priori as study measures.

RESULTS

Fifty-eight percent (N = 30) reported pain and more women than men reported pain (69% vs. 38%, p = .003). Higher general pain interference was associated with lower QoL (r = 0.444, p = .042), but not mood or sleep pain interference (both p's ≥ .451). There was no statistically significant difference in pain interference between genders (p = .138). Nociceptive pain was more common. Levels of nociceptive pain were positively associated with general pain interference, sleep pain interference, and mood pain inference. Neither pain type was associated with QoL (both p's > .082).

CONCLUSIONS

The results from this study reveal key differences/similarities among four interrelated factors: pain, pain interference, QoL, and gender. Pertinent information gathered on pain type and QoL, like increased prevalence of nociceptive pain, can be utilized to formulate proactive and effective treatment plans for individuals with SB that may benefit their sleep pain interference and mood pain interference.

Nociceptive, neuropathic, or nociplastic low back pain? The low back pain phenotyping (BACPAP) consortium's international and multidisciplinary consensus recommendations

The potential to classify low back pain as being characterised by dominant nociceptive, neuropathic, or nociplastic mechanisms is a clinically relevant issue. Preliminary evidence suggests that these low back pain phenotypes might respond differently to treatments; however, more research must be done before making specific recommendations. Accordingly, the low back pain phenotyping (BACPAP) consortium was established as a group of 36 clinicians and researchers from 13 countries (five continents) and 29 institutions, to apply a modified Nominal Group Technique methodology to develop international and multidisciplinary consensus recommendations to provide guidance for identifying the dominant pain phenotype in patients with low back pain, and potentially adapt pain management strategies. The BACPAP consortium's recommendations are also intended to provide direction for future clinical research by building on the established clinical criteria for neuropathic and nociplastic pain. The BACPAP consortium's consensus recommendations are a necessary early step in the process to determine if personalised pain medicine based on pain phenotypes is feasible for low back pain management. Therefore, these recommendations are not ready to be implemented in clinical practice until additional evidence is generated that is specific to these low back pain phenotypes.

Investigation for Factors Affecting Body Perception Disturbance in Patients with Low Back Pain by Mechanism-Based Classification of Pain: A Cross-Sectional Study

Background

Central sensitization is a pathophysiological cause of chronic low back pain and is linked with psychosocial factors. The association between central sensitization (CS) and body perception disturbance is currently unclear, and no prior studies have investigated this relationship in patients with acute or subacute low back pain. The objective of this study was to investigate potential factors that influence body perception disturbance using a mechanistic classification of low back pain.

Methods

This cross-sectional study was conducted at the time of initial physical therapy in patients with low back pain. During the study period, 169 patients were recruited. Pain intensity, disease duration, disability, CS, and body perception disturbance were evaluated. Patients were divided into three groups according to the pathology of low back pain, and multivariate analysis was used to examine factors affecting body perception disturbance. The dependent variable was Fremantle Back Awareness Questionnaire (FreBAQ); the independent variables were age, gender, BMI, VAS, disease duration, RDQ, and CS Inventory-9 (CSI-9).

Results

A total of 117 patients were included in our analysis. According to the mechanistic classification of pain, 66 (56.4%), 36 (30.8%), and 15 (12.8%) patients were categorized as having nociceptive pain (NP), peripheral neuropathic pain (PNP), and CS pain (CSP), respectively. Patients with PNP or CSP were significantly older than those with NP (p  <  0.01). FreBAQ and RDQ scores were significantly higher in patients with CSP than those with NP (p  <  0.05). The results of multiple regression analyses indicated that CSI-9 scores were significantly associated with FreBAQ (p  <  0.01).

Conclusion

Patients with CS syndrome and low back pain tend to have higher CSI-9 scores and be older. Body perception disturbance is influenced by CS or CS syndrome, regardless of the stage of low back pain, suggesting that patients with chronic low back pain tend to have low body image.

Urinary TNF-α as a potential biomarker for chronic primary low back pain

Introduction

Over two thirds of individuals with low back pain (LBP) may experience recurrent or persistent symptoms in the long term. Yet, current data do not allow to predict who will develop chronic low back pain and who will recover from an acute episode. Elevated serum levels of the proinflammatory cytokine tumor necrosis factor-α (TNF-α) have been associated with poor recovery and persistent pain following an acute episode of LBP. Inflammatory cytokines may also mediate mechanisms involved in nociplastic pain, and thus, have significant implications in chronic primary low back pain (CPLBP).

Methods

This study aimed to investigate the potential of urinary TNF-α levels for predicting outcomes and characterizing clinical features of CPLBP patients. Twenty-four patients with CPLBP and 24 sex- and age-matched asymptomatic controls were recruited. Urinary TNF-α concentrations were measured at baseline and after 4 weeks, during which CPLBP patients underwent spinal manipulative therapy (SMT).

Results

Concentrations of TNF-α were found to be elevated in baseline urine samples of CPLBP patients compared to asymptomatic controls. Moreover, these values differed among patients depending on their pain trajectory. Patients with persistent pain showed higher levels of TNF-α, when compared to those with episodic CPLBP. Furthermore, baseline TNF-α concentrations and their changes after 4 weeks predicted alterations in pain intensity and disability following SMT in patients with CPLBP.

Discussion

These findings warrant further research on the potential use of urinary TNF-α concentrations as a prognostic biomarker for CPLBP.

Between guidelines and clinical trials: evidence-based advice on the pharmacological management of non-specific chronic low back pain

The pharmacological management of nonspecific chronic low back pain (NCLBP) aims to restore patients' daily activities and improve their quality of life. The management of NCLBP is not well codified and extremely heterogeneous, and residual symptoms are common. Pharmacological management should be considered as co-adjuvant to non-pharmacological therapy, and should be guided by the symptoms reported by the patients. Depending on the individual severity of NCLPB, pharmacological management may range from nonopioid to opioid analgesics. It is important to identify patients with generalized sensory hypersensitivity, who may benefit from dedicated therapy. This article provides an evidence-based overview of the principles of pharmacological management of NCLPB.

High intensity training improves symptoms of central sensitization at six-month follow-up in persons with chronic nonspecific low back pain: Secondary analysis of a randomized controlled trial

BACKGROUND

High intensity training (HIT) improves disability and physical fitness in persons with chronic nonspecific low back pain (CNSLBP). However, it remains unclear if HIT affects pain processing and psychosocial factors.

OBJECTIVE

To evaluate 1) the effects of HIT on symptoms of central sensitization and perceived stress and 2) the relationship of symptoms of central sensitization and perceived stress with therapy success, at six-month follow-up, in persons with CNSLBP.

METHODS

This is a secondary analysis of a previously published randomized controlled trial. Persons with CNSLBP (n = 51, age=43.6y) completed the Central Sensitization Inventory (CSI) and Perceived Stress Scale (PSS) at baseline (PRE) and six months after 12-week of HIT consisting of concurrent exercise therapy (FU). Two groups were formed based on CSI scores (low-CSI/high-CSI). First, linear mixed models were fitted for each outcome, with time and groups as covariates. Multiple comparisons were executed to evaluate group (baseline), time (within-group), and interaction (between-group) effects. Second, correlation and regression analyses were performed to evaluate if baseline and changes in CSI/PSS scores were related to therapy success, operationalized as improvements on disability (Modified Oswestry Disability Index), and pain intensity (Numeric Pain Rating Scale).

RESULTS

Total sample analyses showed a decrease in both CSI and PSS. Within-group analyses showed a decrease of CSI only in the high-CSI group and a decrease of PSS only in the low-CSI group. Between-group analyses showed a pronounced decrease favouring high-CSI (mean difference: 7.9; 95%CI: 2.1, 12.7) and no differences in PSS (mean difference: 0.1; 95%CI: -3.0, 3.2). CSI, but not PSS, was weakly related to therapy success.

CONCLUSION

HIT improves symptoms of central sensitization in persons with CNSLBP. This effect is the largest in persons with clinically relevant baseline CSI scores. HIT also decreases perceived stress.

COVID-19-Related Neuropathic Pain: A Systematic Review and Meta-Analysis

INTRODUCTION

SARS-CoV-2, responsible for the coronavirus disease (COVID-19) pandemic, may impact other systems apart from the respiratory system, including the nervous system. In this systematic review, we aimed to establish the prevalence and determinants of neuropathic pain amongst COVID-19-infected individuals.

METHODOLOGY

A literature search in the PubMed database was performed and 11 papers were eligible for inclusion in this systematic review and meta-analysis.

RESULTS

The pooled prevalence of COVID-19-related neuropathic pain was 6.7% (95% CI: 4.7-9.5%) for hospitalised patients during the acute phase and 34.3% (95% CI: 14.3-62%) for long COVID patients. The identified risk factors for COVID-19-related neuropathic pain development included depression, COVID-19 severity and azithromycin use.

CONCLUSIONS

Neuropathic pain is a very common symptom in long COVID, indicating the urgency for further research in this direction.

Post-amputation pain: Comparing pain presentations between adults with and without increased amputated-region sensitivity

OBJECTIVE

Among adults with persistent post-amputation pain, increased amputated-region pain sensitivity may reflect peripheral sensitization or indicate underlying central sensitization. To determine whether underlying central sensitization may contribute to increased pain sensitivity in this population, this study compared clinical signs and symptoms associated with central sensitization between adults with post-amputation pain who demonstrate or lack increased amputated-region sensitivity (as compared to reference data).

DESIGN

Cross-sectional.

SUBJECTS

Ninety-nine adults (60 with a unilateral, transtibial amputation and post-amputation pain, 39 pain-free controls with intact limbs).

METHODS

Participants underwent pain-pressure threshold testing of amputated-region and secondary (non-amputated region) sites and completed outcome measures assessing central sensitization symptoms (Patient-Reported Outcomes Measurement Information System® pain intensity and interference domains, Central Sensitization Inventory). Among the full sample, the presence and frequency of specific central sensitization symptoms were evaluated. Participants with post-amputation pain were then grouped based on whether normalized, amputated-region pain-pressure thresholds fell below (i.e., sensitive) or above (i.e., non-sensitive) the 25th percentile of sex-specific reference data. Between-group differences in normalized secondary-site sensitivity were evaluated using a multivariate analysis of variance; central sensitization symptom scores were compared using a Kruskal-Wallis test.

RESULTS

Noteworthy symptoms associated with central sensitization (e.g., fatigue, sleep disturbance, cognitive difficulty) were reported by 33%-62% of participants. Secondary-site pain sensitivity was greater among individuals with increased amputated-region sensitivity (n = 24) compared to peers without increased amputated-region sensitivity ([n = 36], mean difference > 1.33 standard deviation [SD], p < 0.001). Central sensitization symptom scores, however, were similar between groups (p > 0.187).

CONCLUSIONS

Participants with increased amputated-region sensitivity demonstrate generalized, secondary-site pain hypersensitivity, potentially indicating underlying central sensitization. Central sensitization symptom scores, however, were similar between groups, suggesting differences in physiological pain sensitivity may not manifest in subjective post-amputation pain descriptions.

Understanding the clinical profile of patients with frozen shoulder: a longitudinal multicentre observational study

INTRODUCTION

There is a large diversity in the clinical presentation of frozen shoulder (FS) and the clinical outcome is not always satisfactory. The aim of the current study was to examine to what extent range of motion (ROM) limitation, metabolic factors (diabetes mellitus and thyroid disorders), autonomic symptoms and pain sensitivity may contribute to the prognosis in terms of shoulder pain and disability and quality of life in patients with FS.

METHODS

Patients with stage 1 or 2 FS were longitudinally followed-up during 9 months after baseline assessment. They completed six questionnaires and underwent quantitative sensory testing (pressure pain thresholds, temporal summation and conditioned pain modulation) and ROM assessment.

RESULTS

One hundred and forty-nine patients with FS were initially recruited and 121 completed at least one follow-up measurement. Shoulder pain and disability improved over time and diabetes mellitus was found to be a prognostic factor for final outcome. Several domains of quality of life also improved over time and external rotation ROM, diabetes mellitus, thyroid disorder and autonomic symptoms were found to be prognostic factors for final outcome. These prognostic factors explained 2.5%-6.3% of the final outcome of shoulder pain and disability and quality of life.

DISCUSSION AND CONCLUSION

In patients with FS, prognostic variables were able to predict different outcomes, indicating that outcomes in this population can be variable-dependent. Other variables not explored in this study might contribute to the prognosis of patients with FS, which should be investigated in future research. In clinical practice, baseline assessment of prognostic factors and focusing on a more holistic approach might be useful to inform healthcare practitioners about progression of patients with FS during a 9-month period.

Resistance training protects against muscle pain through activation of androgen receptors in male and female mice

ABSTRACT

Resistance training-based exercise is commonly prescribed in the clinic for the treatment of chronic pain. Mechanisms of aerobic exercise for analgesia are frequently studied, while little is known regarding resistance training mechanisms. We developed a resistance training model in mice and hypothesized resistance training would protect against development of muscle pain, mediated through the activation of androgen receptors. Activity-induced muscle hyperalgesia was produced by 2 injections of pH 5.0 stimuli with fatiguing muscle contractions. Resistance training was performed by having mice climb a ladder with attached weights, 3 times per week. Resistance training acutely increased blood lactate and prolonged training increased strength measured via forepaw grip strength and 1 repetition maximum, validating the exercise program as a resistance training model. Eight weeks of resistance training prior to induction of the pain model blocked the development of muscle hyperalgesia in both sexes. Resistance training initiated after induction of the pain model reversed muscle hyperalgesia in male mice only. A single resistance training bout acutely increased testosterone in male but not female mice. Administration of the androgen receptor antagonist flutamide (200 mg pellets) throughout the 8-week training program blocked the exercise-induced protection against muscle pain in both sexes. However, single administration of flutamide (1, 3, 10 mg/kg) in resistance-trained animals had no effect on existing exercise-induced protection against muscle pain. Therefore, resistance training acutely increases lactate and testosterone and strength overtime. Eight weeks of resistance training prevents the development of hyperalgesia through the activation of androgen receptors in an animal model of muscle pain.

The effect of neuropathic pain on quality of life, depression levels, and sleep quality in patients with combat-related extremity injuries

Purpose: There is limited research on the effects of neuropathic pain (NP) on quality of life, depression levels, and sleep quality in patients with combat-related extremity injuries. This study evaluated whether patients with combat-related extremity injuries with and without NP had differences in quality of life, sleep quality, and depression levels.Methods: A total of 98 patients with combat-related extremity injuries, 52 with NP and 46 without, were included in this cross-sectional study. The presence of NP was determined using the Leeds Assessment of Neuropathic Symptoms and Signs questionnaire. The outcome measures were a visual analogue scale (VAS), the 36-Item Short Form Survey, the Beck Depression Inventory, and the Pittsburgh Sleep Quality Index (PSQI).Results: The VAS subparameter scores for pain (all P˂0.05), PSQI sleep duration subscale scores (P=0.025), PSQI sleep disturbance subscale scores (P=0.016), and PSQI total scores (P=0.020) were significantly higher in patients with NP than those without. Logistic regression analysis showed that VAS scores of 5 and above for average pain during the previous 4 weeks contributed independently to the prediction of NP.Conclusions: Patients with combat-related extremity injuries with NP had more pain and poorer sleep quality than those without NP. Sleep quality should be evaluated as part of the diagnostic work-up in patients with combat-related extremity injury with NP, and interventions to improve sleep quality may help manage NP in this patient group.

An observational study of centrally facilitated pain in individuals with chronic low back pain

Introduction

Central pain facilitation can hinder recovery in people with chronic low back pain (CLBP).

Objectives

The objective of this observational study was to investigate whether indices of centrally facilitated pain are associated with pain outcomes in a hospital-based cohort of individuals with CLBP undertaking a pain management programme.

Methods

Participants provided self-report and pain sensitivity data at baseline (n = 97) and again 3 months (n = 87) after a cognitive behavioural therapy-based group intervention including physiotherapy. Indices of centrally facilitated pain were pressure pain detection threshold, temporal summation and conditioned pain modulation at the forearm, Widespread Pain Index (WPI) classified using a body manikin, and a Central Mechanisms Trait (CMT) factor derived from 8 self-reported characteristics of anxiety, depression, neuropathic pain, fatigue, cognitive dysfunction, pain distribution, catastrophizing, and sleep. Pain severity was a composite factor derived from Numerical Rating Scales. Cross-sectional and longitudinal regression models were adjusted for age and sex.

Results

Baseline CMT and WPI each was associated with higher pain severity (CMT: r = 0.50, P < 0.001; WPI: r = 0.21, P = 0.04) at baseline and at 3 months (CMT: r = 0.38, P < 0.001; WPI: r = 0.24, P = 0.02). High baseline CMT remained significantly associated with pain at 3 months after additional adjustment for baseline pain (β = 2.45, P = 0.04, R 2 = 0.25, P < 0.0001). Quantitative sensory testing indices of pain hypersensitivity were not significantly associated with pain outcomes at baseline or at 3 months.

Conclusion

Central mechanisms beyond those captured by quantitative sensory testing are associated with poor CLBP outcome and might be targets for improved therapy.

Use of the painDETECT to discriminate musculoskeletal pain phenotypes

Background

Musculoskeletal pain patients present similar pain characteristics regardless of the clinical diagnosis. PainDETECT questionnaire is useful for screening neuropathic-like symptoms in many musculoskeletal conditions. However, no previous studies compared pain phenotypes of patients with musculoskeletal pain using the painDETECT. Therefore, the current study aimed to compare the pain characteristics of patients with musculoskeletal pain classified according to the painDETECT as nociceptive pain, unclear, and neuropathic-like symptoms.

Methods

A cross-sectional study was conducted in 308 participants with musculoskeletal pain. Demographic and clinical characteristics of the participants were examined. Neuropathic-like symptoms, pain intensity, pain area, Central Sensitization-related sign and symptoms, functional limitation, and conditioned pain modulation were assessed in patients with musculoskeletal pain. Independent one-way analysis of variance (ANOVA) was used to test for between-group differences for the outcome measures with continuous variables and Pearson chi-square test verified between-group differences on the efficiency of the conditioned pain modulation.

Results

Participants had a mean age of 52.21 (±15.01) years old and 220 (71.42%) were females. One hundred seventy-three (56.16%) participants present nociceptive pain, 69 (22.40%) unclear, and 66 (21.42%) neuropathic-like symptoms. A one-way ANOVA showed differences for the pain intensity [F (2,305) = 20.097; p < .001], pain area [F (2,305) = 28.525; p < .001], Central Sensitization-related sign and symptoms [F (2,305) = 54.186; p < .001], and functional limitation [F (2,256) = 8.061; p < .001]. However, conditioned pain modulation was similarly impaired among the three groups (X² = 0.333, p = 0.847).

Conclusion

Patients with neuropathic-like symptoms revealed unfavorable pain characteristics compared to their counterparts, including pain intensity, generalized pain, Central Sensitization-related sign and symptoms, and functional limitation.

Does aerobic exercise effect pain sensitisation in individuals with musculoskeletal pain? A systematic review

Background

Pain sensitisation plays a major role in musculoskeletal pain. However, effective treatments are limited, and although there is growing evidence that exercise may improve pain sensitisation, the amount and type of exercise remains unclear. This systematic review examines the evidence for an effect of aerobic exercise on pain sensitisation in musculoskeletal conditions.

Methods

Systematic searches of six electronic databases were conducted. Studies were included if they examined the relationship between aerobic physical activity and pain sensitisation in individuals with chronic musculoskeletal pain, but excluding specific patient subgroups such as fibromyalgia. Risk of bias was assessed using Cochrane methods and a qualitative analysis was conducted.

Results

Eleven studies (seven repeated measures studies and four clinical trials) of 590 participants were included. Eight studies had low to moderate risk of bias. All 11 studies found that aerobic exercise increased pressure pain thresholds or decreased pain ratings in those with musculoskeletal pain [median (minimum, maximum) improvement in pain sensitisation: 10.6% (2.2%, 24.1%)]. In these studies, the aerobic exercise involved walking or cycling, performed at a submaximal intensity but with incremental increases, for a 4-60 min duration. Improvement in pain sensitisation occurred after one session in the observational studies and after 2-12 weeks in the clinical trials.

Conclusions

These findings provide evidence that aerobic exercise reduces pain sensitisation in individuals with musculoskeletal pain. Further work is needed to determine whether this translates to improved patient outcomes, including reduced disability and greater quality of life.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05047-9.

Central sensitization inventory in endometriosis

ABSTRACT

A key clinical problem is identifying the patient with endometriosis whose pain is complicated by central nervous system sensitization, where conventional gynecologic treatment (eg, hormonal therapy or surgery) may not completely alleviate the pain. The Central Sensitization Inventory (CSI) is a questionnaire previously validated in the chronic pain population. The objective of this study was an exploratory proof-of-concept to identify a CSI cutoff in the endometriosis population to discriminate between individuals with significant central contributors (identified by central sensitivity syndromes [CSS]) to their pain compared to those without. We analyzed a prospective data registry at a tertiary referral center for endometriosis, and included subjects aged 18 to 50 years with endometriosis who were newly or re-referred to the center in 2018. The study sample consisted of 335 subjects with a mean age of 36.0 ± 7.0 years. An increasing number of CSS was significantly correlated with dysmenorrhea, deep dyspareunia, dyschezia, and chronic pelvic pain scores (P < 0.001), and with the CSI score (0-100) (r = 0.731, P < 0.001). Receiver operating characteristic analysis indicated that a CSI cutoff of 40 had a sensitivity of 78% (95% CI: 72.7%-84.6%) and a specificity of 80% (95% CI: 70.3%-84.5%) for identifying a patient with endometriosis with ≥3 CSS. In the group with CSI ≥ 40, 18% retrospectively self-reported pain nonresponsive to hormonal therapy and 40% self-reported daily pain, compared with 6% and 20% in the CSI < 40 group (P = 0.003 and 0.002, respectively). In conclusion, a CSI ≥ 40 may be a practical tool to help identify patients with endometriosis with pain contributors related to central nervous system sensitization.

Assessment of the neuropathic component in a chronic low back pain syndrome

Background/Aim. Chronic low back pain syndrome (CLBPS) is the most common cause of functional disability and loss of working ability in developed countries. Some research shows that neuropathic pain (NP) is present in almost 50% of patients with CLPBS. The aim of this study was to determine the characteristics of NP and its impact on quality of life (QoL) in patients with CLBPS. Methods. Patients were tested using three questionnaires for NP: Pain Detect Questionnaire, Leeds Assessment of Neuropathic Symptoms and Signs, and Douleur Neuropathique 4 questions. Thirty-two patients diagnosed with NP based on current clinical criteria and with positive results for NP on all three NP questionnaires formed an experimental group. A control group consisted of 32 patients with CLBPS who did not fulfill clinical criteria for NP and were negative for NP on all three questionnaires. Hamilton depression and anxiety rating scales (Ham-D and Ham-A, respectively) and Short Form (SF)-36 questionnaire were also applied. Results. According to magnetic resonance imaging (MRI), disc herniation was typically detected in the experimental group, while degenerative changes were commonly found in the control group. Patients from the experimental group had significantly greater intensity of pain, pain radiation in the legs, and the pain was usually presented as episodes of sudden attacks with mild pain between them. The most distinctive features of NP were allodynia, electric shock sensation, and hypoesthesia to prick. Patients from the experimental group also had significantly higher depression and anxiety scores, as well as worse QoL compared to the control group, especially in mental domains. Predictors of worse QoL in the patients with CLBPS were a higher level of anxiety and depression. Conclusion. The presence of allodynia, electric shock-like sensations, and hypoesthesia to prick in patients with CLBPS suggest NP. CLBPS patients with NP had worse scores in mental domains of QoL compared to CLPBS patients without NP.

The Definition, Assessment, and Prevalence of (Human Assumed) Central Sensitisation in Patients with Chronic Low Back Pain: A Systematic Review

Central sensitisation is assumed to be one of the underlying mechanisms for chronic low back pain. Because central sensitisation is not directly assessable in humans, the term 'human assumed central sensitisation' (HACS) is suggested. The objectives were to investigate what definitions for HACS have been used, to evaluate the methods to assess HACS, to assess the validity of those methods, and to estimate the prevalence of HACS. Database search resulted in 34 included studies. Forty different definition references were used to define HACS. This review uncovered twenty quantitative methods to assess HACS, including four questionnaires and sixteen quantitative sensory testing measures. The prevalence of HACS in patients with chronic low back pain was estimated in three studies. The current systematic review highlights that multiple definitions, assessment methods, and prevalence estimates are stated in the literature regarding HACS in patients with chronic low back pain. Most of the assessment methods of HACS are not validated but have been tested for reliability and repeatability. Given the lack of a gold standard to assess HACS, an initial grading system is proposed to standardize clinical and research assessments of HACS in patients with a chronic low back.

Do Limited English Proficiency and Language Moderate the Relationship Between Mental Health and Pain?

AIM

To explore whether the relationship between mental health diagnosis (i.e., mood or neurotic, stress-related, or somatoform disorder) and pain is moderated by language in patients with limited English proficiency (LEP). Southeast Asian languages (i.e., Hmong, Lao, Khmer) and Spanish were compared with English.

METHOD

A retrospective data mining study was conducted (n = 79,109 visits). Pain scores, language, mental health diagnoses, age, sex, race, ethnicity, and pain diagnosis were obtained from electronic medical records. Cragg two-equation hurdle regression explored: (1) the effect of patient language and mental health diagnosis on pain and (2) the interaction between language and mental health diagnosis on pain.

RESULTS

Visits were primarily for female (62.45%), White (80.10%), not Hispanic/Latino (96.06%), and English-speaking (97.85%) patients. Spanish or Southeast Asian language increased chances of reporting any pain (i.e., pain score of 0 versus ≥1) and pain severity in visits with pain scores ≥1, whereas mental health diagnosis decreased chances of reporting any pain and pain severity. The combination of Southeast Asian language and mood disorder contributed to higher chances of reporting any pain (odds ratio [OR] = 1.78, p<.001) but no difference in severity. A similar trend was observed for Southeast Asian language and neurotic disorder (OR = 1.29, p=.143). In contrast, the combination of Spanish language and mood (p = .066) or neurotic (p = .289) disorder contributed to lower pain severity but did not change the chances of reporting any pain.

CONCLUSIONS

LEP and patient language should be considered during pain assessment within the context of mental health.

Correlation between change in pain, disability, and surface electromyography topographic parameters after interferential current treatment in patients with chronic low back pain

[Purpose] Surface electromyography (SEMG) topography is used to objectively assess patients with low back pain (LBP). This study aimed to investigate the correlation between SEMG topographic variables, pain, and disability in patients with chronic LBP (CLBP) after interferential current (IFC) treatment, and to evaluate IFC treatment efficacy using SEMG topography. [Participants and Methods] Twenty nine patients with CLBP were recruited for a 6-week IFC treatment. Pain and disability scores, and the root-mean-square difference (RMSD) of SEMG topographic variables (relative areas [RAs] at flexion and extension) were compared before and after the intervention by repeated measures ANOVA; the correlation between variables was also explored and p-value was set at 0.001. [Results] Significant positive correlations between changes in pain score and the RMSD of RA at flexion (r(29)=0.593), and between changes in pain and disability scores (r(29)=0.426) were observed. All participants showed statistically significant improvements in the RMSD of RA at flexion, pain score, and disability score after IFC treatment. [Conclusion] SEMG topographic variables are closely associated with changes in pain score in patients with CLBP after IFC treatment. The RMSD of RA at flexion can be used as an objective marker in IFC treatment efficacy evaluation.

Adaptive body awareness predicts fewer central sensitization-related symptoms and explains relationship between central sensitization-related symptoms and pain intensity: A cross-sectional study among individuals with chronic pain

BACKGROUND

Central sensitization (CS), defined as the amplification of neural signaling within the CNS that elicits pain hypersensitivity, is thought be a characteristic of several chronic pain conditions. Maladaptive body awareness is thought to contribute and maintain CS. Less is known about the relationship between CS and adaptive body awareness.

PURPOSE

This cross-sectional study investigated relationships among self-reported adaptive body awareness (Multidimensional Interoceptive Awareness Scale-2; MAIA-2), CS-related symptoms (Central Sensitization Inventory; CSI), and pain intensity and further delineate potential direct and indirect links among these constructs.

METHODS

Online surveys were administered to 280 individuals with chronic pain reporting elevated CSI scores. Strategic sampling targeted respondents to reflect the 2010 census. Pearson's correlations characterized overall relationship between variables. Multiple regression analyses investigated potential direct links. A path analysis assessed mediational effects of CS-related symptoms on the relationship between adaptive body awareness and pain intensity.

RESULTS

CSI demonstrated strong, inverse correlations with some MAIA-2 subscales, but positive correlations with others. Higher CSI scores predicted greater pain intensity (b = 0.049, p ≤ 0.001). Two MAIA-2 subscales, Not-Distracting (b = -0.56, p ≤ 0.001) and Not-Worrying (b = -1.17, p ≤ 0.001) were unique predictors of lower CSI. Not-Distracting (b = -0.05, p = 0.003) and Not-Worrying (b = -0.06, p = 0.007) uniquely predicted lower pain intensity. CSI completely mediated the relationship between adaptive body awareness and pain intensity [point estimate = -0.04; 95% bootstrap confident intervals (CI) = -0.05 to -0.02].

CONCLUSIONS

Findings also support future research to explore causal relationships of variables. Findings suggest that frequency of attention to bodily sensations is distinct from cognitive-affective appraisal of bodily sensation, and the two distinct higher order processes may have divergent influences on perceived pain and CS-related symptoms. Results also support future research to explore causal relationships of variables.

PROMIS Neuropathic and Nociceptive Pain Quality in Musculoskeletal Pain Presentations

OBJECTIVE

Musculoskeletal pain is a significant contributor to the global disease burden. Management of musculoskeletal pain where a neuropathic component is present can be challenging. This study evaluated the internal structure of the Patient-Reported Outcome Measures Information System (PROMIS) pain quality scales, explored the prevalence of neuropathic and nociceptive pain, and identified health demographics and behaviors related to musculoskeletal pain presentations.

METHODS

Patients presenting to the Victoria University Osteopathy Clinic (Melbourne, Vic., Australia) were invited to complete a health demographics and behaviors questionnaire, and the PROMIS Neuropathic (NeuroPQ) and Nociceptive (NociPQ) pain quality scales, before their initial consultation. Descriptive, inferential, and correlation statistics were used to evaluate the PROMIS scales, health demographics, and behaviors. Mokken scale analysis was used to evaluate the internal structure and dimensionality of the NeuroPQ and NociPQ scales.

RESULTS

Three hundred eighty-three (N=383) patients completed the measures. Mokken scaling suggested the PROMIS scales demonstrated acceptable internal structure and were unidimensional. Over 22% of patients demonstrated cutoff scores above 50, suggesting a substantive neuropathic pain component to their musculoskeletal presentation. Patients who reported cigarette smoking, not being born in Australia or not speaking English at home, demonstrated higher NeuroPQ scores. Females demonstrated significantly higher NociPQ scores than males. Pain intensity demonstrated small to medium correlations with NeuroPQ and NociPQ scores.

DISCUSSION

This study provides support for the use of the NeuroPQ and NociPQ scales in musculoskeletal pain patients. Associations with health demographics and behaviors were identified, and patients typically experienced a combination of neuropathic and nociceptive pain.

Effect of an intensive cervical traction protocol on mid-term disability and pain in patients with cervical radiculopathy: An exploratory, prospective, observational pilot study

BACKGROUND

Cervical radiculopathy is a relatively common and disabling condition involving local pain in the neck region and pain that radiates into the upper limb. Recent data suggest that cervical traction may effectively reduce disability and pain, with a dose-response relationship. The main aim of this study was therefore to evaluate the mid-term effect of an intensive cervical traction protocol for patients with cervical radiculopathy on disability, and to compare the effects with those reported by non-intensive protocols in the literature.

METHODS

We conducted a prospective open observational study of 36 patients referred by their general practitioner for symptoms suggestive of cervical radiculopathy. All patients underwent the same treatment: a 30-minute cervical traction protocol, twice a day, for five consecutive days. The main objective was the evaluation of disability at 3 months. We evaluated at baseline (D1), the end of the protocol (D5) and at mid-term (M3) disability, cervical pain, radiating pain, pain on motor imagery, presence of neuropathic pain and medication consumption. The primary outcome was the proportion of patients for whom the Neck Disability Index improved by more than the minimum clinically important difference of 7 points by M3.

RESULTS

Thirty-six patients were included in this study. The Neck Disability Index improved by more than the minimum clinically important difference in 48.3% at M3. Mean Neck Disability Index (p < .001), mean cervical VAS (p < .001), mean radiating VAS (p < .001), and mean VAS for imagined lateral flexion and rotation (p < .002) improved significantly from D1 to D5 and from D1 to M3. Consumption of medication reduced at each time point. The proportion of patients with neuropathic pain reduced from 61.1% at D1 to 33.3% at D5 and 48.3% at M3.

CONCLUSION

Disability reduced by more than the minimum clinically important difference in almost half of the participants following the intensive traction protocol. These results are encouraging and suggest that this complex condition can be treated with relatively simple methods.

Heightened pain facilitation rather than impaired pain inhibition distinguishes those with moderate/severe disability in work-related neck pain

ABSTRACT

To better understand the mechanisms underpinning work-related neck pain, this cross-sectional and single-blinded study compared somatosensory profiles among sonographers with varied neck disability levels. Based on K-mean cluster analysis of scores on the neck disability index (NDI), participants were classified into no (NDI ≤ 8%, n = 31, reference group), mild (NDI = 10%-20%, n = 43), or moderate/severe (NDI ≥ 22%, n = 18) disability groups. Data were collected on bodily pain distribution and severity and psychological measures including depression, anxiety, pain-catastrophizing, and fear-avoidance beliefs using validated scales. Participants attended 1 session of quantitative sensory testing performed according to a standardized protocol, including local and remote thermal and mechanical pain thresholds, temporal summation of pain (TSP), conditioned pain modulation, and an exercise-induced analgesia paradigm. Compared with participants with no and mild disability, those with moderate/severe disability showed more widespread pain, cold and mechanical hyperalgesia at a remote nonpainful site, and significantly higher TSP. Participants with mild disability demonstrated significantly higher TSP than those with no disability. These group differences were attenuated after adjusting for depression or anxiety, indicating these psychological factors may mediate the somatosensory changes associated with neck disability. Group differences were not found for conditioned pain modulation or exercise-induced analgesia. These findings suggest that heightened pain facilitation, rather than impaired pain inhibition may underpin nociplastic pain in participants with moderate/severe disability, and it may be associated with depression and anxiety. Clinicians should be aware that individuals with work-related neck pain presenting with moderate/severe disability display distinct somatosensory features and tailor management strategies accordingly.

Nociplastic Pain Criteria or Recognition of Central Sensitization? Pain Phenotyping in the Past, Present and Future

Recently, the International Association for the Study of Pain (IASP) released clinical criteria and a grading system for nociplastic pain affecting the musculoskeletal system. These criteria replaced the 2014 clinical criteria for predominant central sensitization (CS) pain and accounted for clinicians' need to identify (early) and correctly classify patients having chronic pain according to the pain phenotype. Still, clinicians and researchers can become confused by the multitude of terms and the variety of clinical criteria available. Therefore, this paper aims at (1) providing an overview of what preceded the IASP criteria for nociplastic pain ('the past'); (2) explaining the new IASP criteria for nociplastic pain in comparison with the 2014 clinical criteria for predominant CS pain ('the present'); and (3) highlighting key areas for future implementation and research work in this area ('the future'). It is explained that the 2021 IASP clinical criteria for nociplastic pain are in line with the 2014 clinical criteria for predominant CS pain but are more robust, comprehensive, better developed and hold more potential. Therefore, the 2021 IASP clinical criteria for nociplastic pain are important steps towards precision pain medicine, yet studies examining the clinimetric and psychometric properties of the criteria are urgently needed.

Vulvodynia-It Is Time to Accept a New Understanding from a Neurobiological Perspective

Vulvodynia is one the most common causes of pain during sexual intercourse in premenopausal women. The burden of vulvodynia in a woman's life can be devastating due to its consequences in the couple's sexuality and intimacy, in activities of daily living, and psychological well-being. In recent decades, there has been considerable progress in the understanding of vulvar pain. The most significant change has been the differentiation of vulvar pain secondary to pathology or disease from vulvodynia. However, although it is currently proposed that vulvodynia should be considered as a primary chronic pain condition and, therefore, without an obvious identifiable cause, it is still believed that different inflammatory, genetic, hormonal, muscular factors, etc. may be involved in its development. Advances in pain neuroscience and the central sensitization paradigm have led to a new approach to vulvodynia from a neurobiological perspective. It is proposed that vulvodynia should be understood as complex pain without relevant nociception. Different clinical identifiers of vulvodynia are presented from a neurobiological and psychosocial perspective. In this case, strategies to modulate altered central pain processing is necessary, changing the patient's erroneous cognitions about their pain, and also reducing fear avoidance-behaviors and the disability of the patient.

Alpha lipoic acid with pulsed radiofrequency in treatment of chronic lumbosacral radicular pain: A prospective, randomized study

BACKGROUND

The effect of adding alpha lipoic acid (ALA) to pulsed radiofrequency (PRF) for treatment of lumbar-sacral pain was evaluated.

OBJECTIVE

to evaluate the effect of using ALA as an adjuvant therapy with PRF for treatment of chronic lumbosacral radicular pain caused by herniated disc.

METHODS

One hundred twenty patients with lumbo-sacral radicular pain allocated into 2 groups. Group I: treated with PRF at 42°C for 120 seconds. Group II: treated as in group I, plus oral ALA 600 mg (Thiotacid 600 mg, EVA PHARMA, Egypt) three times per day (1800 mg/day) for 3 weeks then 600 mg once daily for 2 weeks. The lumbo-sacral radicular pain evaluated using the numerical rating pain score and Oswestry Disability Index.

RESULTS

Success rate was significantly higher in group II at 3 and 6 months after intervention. The median values of the numerical rating pain score and the Oswestry Disability Index were significantly lower in group II with no significant difference in Epworth Sleepiness Scale. No major complications were reported in both groups.

CONCLUSION

The current study supports the use of ALA with PRF on the dorsal root ganglion for treating lumbosacral radicular pain.

Methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system: a systematic review

ABSTRACT

Mechanism-based classification of pain has been advocated widely to aid tailoring of interventions for individuals experiencing persistent musculoskeletal pain. Three pain mechanism categories (PMCs) are defined by the International Association for the Study of Pain: nociceptive, neuropathic, and nociplastic pain. Discrimination between them remains challenging. This study aimed to build on a framework developed to converge the diverse literature of PMCs to systematically review methods purported to discriminate between them; synthesise and thematically analyse these methods to identify the convergence and divergence of opinion; and report validation, psychometric properties, and strengths/weaknesses of these methods. The search strategy identified articles discussing methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system. Studies that assessed the validity of methods to discriminate between categories were assessed for quality. Extraction and thematic analysis were undertaken on 184 articles. Data synthesis identified 200 methods in 5 themes: clinical examination, quantitative sensory testing, imaging, diagnostic and laboratory testing, and pain-type questionnaires. Few methods have been validated for discrimination between PMCs. There was general convergence but some disagreement regarding findings that discriminate between PMCs. A combination of features and methods, rather than a single method, was generally recommended to discriminate between PMCs. Two major limitations were identified: an overlap of findings of methods between categories due to mixed presentations and many methods considered discrimination between 2 PMCs but not others. The results of this review provide a foundation to refine methods to differentiate mechanisms for musculoskeletal pain.

Hyperalgesia and Central Sensitization in Subjects With Chronic Orofacial Pain: Analysis of Pain Thresholds and EEG Biomarkers

Introduction: The presence of a temporomandibular disorder is one of the most frequent causes of orofacial pain (OFP). When pain continues beyond tissue healing time, it becomes chronic and may be caused, among other factors, by the sensitization of higher-order neurons. The aim of this study is to describe psychological characteristics of patients with chronic OFP, their peripheral pain threshold, and electroencephalography (EEG) recording, looking for possible signs of central sensitization (CS). Materials and methods: Twenty-four subjects with chronic OFP caused by temporomandibular disorder were evaluated using the Research Diagnostic Criteria for Temporomandibular Disorders Axis I and Axis II. Pain intensity, catastrophizing, and presence of CS were assessed through self-reported questionnaires. Pressure pain threshold (PPT) was recorded in facial and peripheral sites; EEG activity was recorded during open and closed eyes resting state and also during the pain threshold assessment. Pain thresholds and EEG recordings were compared with a cohort of pain-free age- and sex-matched healthy subjects. Results: Patients with chronic OFP showed a significant reduction in their pain threshold compared to healthy subjects in all sites assessed. Greater reduction in pain threshold was recorded in patients with more severe psychological symptoms. Decreased alpha and increased gamma activity was recorded in central and frontal regions of all subjects, although no significant differences were observed between groups. Discussion: A general reduction in PPT was recorded in people who suffer from chronic OFP. This result may be explained by sensitization of the central nervous system due to chronic pain conditions. Abnormal EEG activity was recorded during painful stimulation compared to the relaxed condition in both chronic OFP subjects and healthy controls.

A Meta-Analysis of Therapeutic Pain Neuroscience Education, Using Dosage and Treatment Format as Moderator Variables

OBJECTIVES

This meta-analysis aimed to assess the overall effect of therapeutic pain neuroscience education (TPNE) on chronic musculoskeletal pain and to further assess whether such an effect differs by TPNE dosage as well as other treatment format components. Dosage included the number of TPNE sessions provided as well as the amount of time per TPNE session. Structural components included TPNE provided alone as treatment or combined with other pain management modalities, as well as the inclusion of group-based treatment sessions.

METHODS

Electronic databases were utilized to search for randomized controlled trials that included TPNE. The overall effectiveness of TPNE was estimated on 4 pain outcome measures, including kinesiophobia, pain intensity, pain disability, and pain catastrophizing. The differential effectiveness of TPNE was examined using a mixed-methods moderator analysis on various study-level characteristics to identify potential moderators affecting the overall results.

RESULTS

Significant effects of TPNE were found on all the outcome measures. The only moderator that displayed a significant effect was group-based treatment on kinesiophobia (z = -2.23, P < 0.05, 95% confidence interval [CI] -2.70 to -0.20). Between-group analysis revealed that only interventions that included group sessions were found to be statistically significant (z = 2.20, P < 0.05) and displayed a large effect size (d = 0.80, 95% CI 0.09 to 1.50).

DISCUSSION

Therapeutic pain neuroscience education had a statistically significant impact on all the explored pain outcome measures. However, when investigating the treatment dosage and format moderator variables, they appeared to not have a statistically significant effect except for group-based interventions on kinesiophobia levels.

CONCLUSION

This meta-analysis examined the efficacy of TPNE for patients with chronic pain. It assessed various pain outcome measures following intervention. In addition, this research identified that various moderator variables do not have and do have an impact on the treatment modality of TPNE.

Effect of Neural Mobilization on Nerve-Related Neck and Arm Pain: A Randomized Controlled Trial

Purpose: Neural mobilization (NM) is often used to treat nerve-related conditions, and its use is reasonable with nerve-related neck and arm pain (NNAP). The aims of this study were to establish the effect of NM on the pain, function, and quality of life (QOL) of patients with NNAP and to establish whether high catastrophizing and neuropathic pain influence treatment outcomes. Method: A randomized controlled trial compared a usual-care (UC; n = 26) group, who received cervical and thoracic mobilization, exercises, and advice, with an intervention (UCNM; n = 60) group, who received the same treatment but with the addition of NM. Soft tissue mobilization along the tract of the nerve was used as the NM technique. The primary outcomes were pain intensity (rated on the Numerical Pain Rating Scale), function (Patient-Specific Functional Scale), and QOL (EuroQol-5D) at 3 weeks, 6 weeks, 6 months, and 12 months. The secondary outcomes were the presence of neuropathic pain (using the Neuropathic Diagnostic Questionnaire) and catastrophizing (Pain Catastrophising Scale). Results: Both groups improved in terms of pain, function, and QOL over the 12-month period (p < 0.05). No between-groups differences were found at 12 months, but the UCNM group had significantly less pain at 6 months (p = 0.03). Patients who still presented with neuropathic pain (p < 0.001) and high pain catastrophizing (p = 0.02) at 6- and 12-mo follow-ups had more pain. Conclusions: Both groups had similar improvements in function and QOL at 12-month follow-up. The UCNM group had significantly less pain at 6-month follow-up and a lower mean pain rating at 12-month follow-up, although the difference between groups was not significant. Neuropathic pain is common among this population and, where it persisted, patients had more pain and functional limitations at 12-mo follow-up.

Symptoms of central sensitization in patients with inflammatory bowel diseases: a case-control study examining the role of musculoskeletal pain and psychological factors

OBJECTIVES

Musculoskeletal (MSK) pain is a common complaint in patients with inflammatory bowel diseases (IBD). MSK pain in IBD has previously demonstrated association with symptoms of central sensitization; however it is uncertain whether these symptoms are influenced simply by the presence of MSK pain and/or IBD. Primary aim of this study was to investigate whether symptoms of central sensitization differed across three groups: IBD patients with and without MSK pain and healthy controls. Secondary aim was to investigate between-group differences for measures of somatosensory functioning.

METHODS

Cross-sectional study was performed on adults with IBD. Assessments included: central sensitization inventory (CSI), pressure pain threshold, temporal summation, conditioned pain modulation, perceived stress, affect style, anxiety, depression, and pain catastrophizing. One-way analyses of variance and covariance were used to investigate between-group differences for measures of central sensitization and potential confounding by psychological factors.

RESULTS

Study participants (n=66) were age/gender matched across three study groups. Between-group differences were solely demonstrated for CSI scores [F(2,63)=19.835, p<0.001, r=0.62], with IBD patients with MSK pain demonstrating the highest CSI scores and healthy controls the lowest. After controlling for individual psychological features, post hoc comparisons indicated that CSI scores were significantly different between-groups (p≤0.025) after controlling for most psychological variables, with the exception of perceived stress (p=0.063) and pain catastrophizing (p=0.593).

CONCLUSIONS

IBD patients as a whole demonstrated significantly greater symptoms of central sensitization compared to healthy controls. However, IBD patients with persistent MSK pain demonstrated the greatest symptoms of central sensitization compared to patients without MSK pain and healthy controls. Between-group differences for CSI in IBD patients with MSK were not confounded by psychological features.

IMPLICATIONS

Study results indicate that persistent MSK pain in IBD represents patients with greater central sensitization symptomology. This increased symptomology is suggestive of underlying mechanisms related to central sensitization, highlighting patient potentially at risk for worse pain experiences.

Prescription of exercises for the treatment of chronic pain along the continuum of nociplastic pain: A systematic review with meta-analysis

BACKGROUND AND OBJECTIVE

To compare different exercise prescriptions for patients with chronic pain along the continuum of nociplastic pain: fibromyalgia, chronic whiplash-associated disorders (CWAD), and chronic idiopathic neck pain (CINP).

DATABASES AND DATA TREATMENT

Randomized controlled trials comparing different exercise parameters were included. The search was performed in the databases Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINAHL and PEDro. Data on the parameters for the physical exercise programs for pain management were extracted for analysis.

RESULTS

Fifty studies with 3,562 participants were included. For fibromyalgia, both aerobic strengthening exercises were similar and better than stretching exercises alone. Exercises could be performed in 50- to 60-min supervised sessions, 2 to 3 times a week, for 13 weeks or more. For CWAD, body awareness exercises were similar to combined exercises, and there was no difference in adding sling exercises to a strengthening exercise program. The exercises could be performed in 90-min supervised sessions, twice a week, for 10 to 16 weeks. For CINP, motor control exercises and nonspecific muscle strengthening had a similar effect. Exercises could be performed in 30- to 60-min supervised sessions, 2 to 3 times a week, for 7 to 12 weeks.

CONCLUSIONS

The choice of parameters regarding exercises should emphasize global exercises in nociplastic pain conditions (such as fibromyalgia and CWAD) and specific exercises in non-nociplastic pain conditions (such as CINP) and be based on patient's preference and therapist's skills.

PROSPERO REGISTRATION NUMBER

CRD42019123271.

SIGNIFICANCE

The pain mechanism must be considered to optimize exercise prescription in patients with different chronic pain profiles. The main message of this article is that low to moderate intensity global exercises performed for a long period of treatment should be performed in patients with nociplastic pain predominance. Additionally, focused and intense exercises for a short period of treatment can be prescribed for patients with nociceptive pain predominance.

Nutritional intervention in chronic pain: an innovative way of targeting central nervous system sensitization?

INTRODUCTION

Few treatment programs for chronic pain nowadays take a dietary pattern or adipose status into account.

AREAS COVERED

An important role of neuroinflammation in chronic pain is now well established, at least in part due to increased central nervous system glial activation. Based on preclinical studies, it is postulated that the interaction between nutrition and central sensitization is mediated via bidirectional gut-brain interactions. This model of diet-induced neuroinflammation and consequent central sensitization generates a rationale for developing innovative treatments for patients with chronic pain. Methods: An umbrella approach to cover the authors' expert opinion within an evidence-based viewpoint.

EXPERT OPINION

A low-saturated fat and low-added sugar dietary pattern potentially decreases oxidative stress, preventing Toll-like receptor activation and subsequent glial activation. A low-saturated fat and low-added sugar diet might also prevent afferent vagal nerve fibers sensing the pro-inflammatory mediators that come along with a high-(saturated) fat or energy-dense dietary pattern, thereby preventing them to signal peripheral inflammatory status to the brain. In addition, the gut microbiota produces polyamines, which hold the capacity to excite N-methyl-D-aspartate receptors, an essential component of the central nervous system sensitization. Hence, a diet reducing polyamine production by the gut microbiota requires exploration as a therapeutic target for cancer-related and non-cancer chronic pain.

Rehabilitation for Low Back Pain: A Narrative Review for Managing Pain and Improving Function in Acute and Chronic Conditions

Low back pain (LBP) is prevalent and may transition into chronic LBP (cLBP) with associated reduced quality of life, pain, and disability. Because cLBP affects a heterogenous population, rehabilitation efforts must be individualized to meet the needs of various patient populations as well as individuals. This narrative review evaluated the many approaches to LBP rehabilitation including treatment-based classifications and specific types of rehabilitation efforts from exercise and physical therapy to spinal manipulation and bracing. Clinicians caring for patients with LBP or cLBP must be aware of the various options to find the right treatment course for each patient. In many cases, with proper patient expectations and care, nonpharmacological options may suffice to manage cLBP. While there is a rightful role for analgesics in the management of LBP, nonpharmacological options should be seriously considered, as they can play an important and health-sustaining role in patient management.

Pain Expansion and Severity Reflect Central Sensitization in Primary Care Patients with Greater Trochanteric Pain Syndrome

OBJECTIVES

The aims of this study were twofold: 1) to evaluate the differences in pain sensitivity of patients with greater trochanteric pain syndrome (GTPS) and 2) to examine the association between pain expansion, pain severity, and pain-related central sensitization somatosensory variables in patients with GTPS.

STUDY DESIGN

A cross-sectional study.

SETTING

Primary health care centers.

SUBJECTS

The sample consisted of 49 participants with a mean age of 48.28 ± 8.13 years and included eight males (16.3%) and 41 females (83.7%).

METHODS

Conditioned pain modulation (CPM), pain location, temporal summation, pressure pain detection threshold (PPDT), and pain intensity were recorded. Pain severity was determined with the Graded Chronic Pain Scale (GCPS).

RESULTS

Several participants (34.7%) showed a negative conditioned pain modulation and a statistically significant negative moderate correlation (P < 0.05; r = -0.316) between conditioned pain modulation and right view percentage of pain location. Temporal summation at the major trochanter showed a statistically significant low negative correlation (P < 0.05; r = -0.298). The GCPS exhibited a statistically significant moderately positive correlation (P < 0.01; r = 0.467) with the PPDT at the trochanter and a significant correlation with the postero-superior iliac spine (P < 0.01; r = 0.515) and epicondyle (P < 0.01; r = 0.566).

CONCLUSIONS

Patients with GTPS presented altered CPM, a relationship with more pain areas associated with negative CPM, and a positive association between pain severity and mechanical hyperalgesia at remote sites. Thus, physicians could apply these outcome measurements to assess primary care patients with GTPS and determine the central sensitization presence to prescribe adequate multimodal treatment approaches.

Association between pain phenotype and disease activity in rheumatoid arthritis patients: a non-interventional, longitudinal cohort study

BACKGROUND

In well-controlled rheumatoid arthritis (RA) without significant joint damage, a substantial proportion of patients complain of persistent pain. Previous studies have identified different pain phenotypes in RA, in which non-nociceptive pain phenotypes are associated with higher concurrent disease activity scores. In this longitudinal study, we explored associations between pain phenotypes and long-term disease activity outcome in RA patients. Secondly, we explored whether pain phenotype is associated with comorbid conditions.

METHODS

One hundred eighty established RA patients were classified with a nociceptive (61%) or a non-nociceptive (39%) pain phenotype, based on their responses to the painDETECT-questionnaire. Two years of clinical follow-up data on disease activity outcomes were collected. Information on comorbid diseases was derived from electronic patient files.

RESULTS

Patients with a non-nociceptive pain phenotype showed higher mean disease activity scores (DAS28, 2.57; 95% CI, 2.37-2.77 vs. 2.11; 95% CI, 1.94-2.27; p < 0.001) and a twofold lower chance of achieving sustained DAS28 remission (OR = 0.49; 95% CI, 0.26-0.92; p = 0.020). Only the tender joint count and patient global health significantly differed between the pain phenotype groups. Patients with a non-nociceptive pain phenotype had more often been diagnosed with concurrent fibromyalgia (9.9% vs. 0.9%; p = 0.007) and other pain-associated comorbid diseases (52.1% vs. 35.8%; p = 0.030) compared with patients with a nociceptive pain phenotype.

CONCLUSION

This longitudinal study showed consistently worse long-term disease activity outcomes in RA patients with a non-nociceptive pain phenotype which appeared to be mainly due to differences in the subjective components of the disease activity score.

TRIAL REGISTRATION

The DREAM cohort study is registered in the Netherlands Trial Register: NTR578.

Pain Mechanisms in Low Back Pain: A Systematic Review With Meta-analysis of Mechanical Quantitative Sensory Testing Outcomes in People With Nonspecific Low Back Pain

BACKGROUND

Mechanical quantitative sensory testing (QST) assesses sensory functioning and detects functional changes in (central) nociceptive processing. It has been hypothesized that these functional changes might be apparent in people with nonspecific low back pain (LBP), although the results are mixed.

OBJECTIVE

The aim of this systematic review was to examine whether sensory function, measured with QST, was altered in people with nonspecific LBP.

METHODS

This systematic review was conducted according to PRISMA guidelines. Six databases were searched for relevant literature. Studies comparing mechanical QST measures involving people with subacute and chronic LBP and healthy controls were included if (1) pressure pain thresholds (PPTs), (2) temporal summation, or (3) conditioned pain modulation were reported. Risk of bias was assessed using the Newcastle-Ottawa scale. When possible, the results from different studies were pooled.

RESULTS

Twenty-four studies were included. Scores on the Newcastle-Ottawa scale varied between 1 and 6 points. People with nonspecific LBP, compared to healthy controls, had significantly lower PPTs at remote sites and increased temporal summation at the lower back. The PPTs measured at the scapula were significantly lower in patients with nonspecific LBP than in healthy controls (pooled mean difference, 119.2 kPa; 95% confidence interval: 91.8, 146.6 kPa; P<.001).

CONCLUSION

The PPT measurements at remote body parts were significantly lower in people with nonspecific LBP compared with healthy controls. Temporal summation and conditioned pain modulation measurements had mixed outcomes.

LEVEL OF EVIDENCE

Therapy, level 3a. J Orthop Sports Phys Ther 2019;49(10):698-715. Epub 23 Aug 2019. doi:10.2519/jospt.2019.8876.

Neck pain in South Africa: An overview of the prevalence, assessment and management for the contemporary clinician

BACKGROUND

Neck pain is a prevalent condition and is associated with high levels of disability and pain. The long-term prognosis can be poor, and therefore effective management in the acute stage is important.

OBJECTIVES

To provide an overview of the prevalence of neck pain and physiotherapy management and to provide evidence-informed recommendations for clinical practice within a South African context.

METHOD

The literature was reviewed considering prevalence, risk factors and examination. Management recommendations were derived from the highest levels of evidence of clinical practice guidelines, systematic reviews and randomised clinical trials.

RESULTS

Neck pain is classified into four grades, and three trajectories of recovery have been identified. Although the incidence of neck pain globally is high, in the South African context the majority of the population have limited access to physiotherapy management. Sound clinical reasoning is important in the assessment and decision-making process for management. Exercise, and mobilisation or manipulation are effective treatment options in the management of most types of neck pain. Other physical modalities such as needling, transcutaneous electrical nerve stimulation, laser and intermittent traction may be used as an adjunct to management.

CONCLUSION

The burden of neck pain globally is high; however, there is a lack of information on current practice, prevalence and burden of neck pain in the South African context. Sound evidence-informed clinical reasoning to inform a working diagnosis and to enable patient-centred management is important.

CLINICAL IMPLICATIONS

A thorough assessment is essential to gather information to formulate hypotheses regarding diagnosis and prognosis for neck pain. Exercise, and mobilisation or manipulation are effective management options.

Quantitative sensory testing and predicting outcomes for musculoskeletal pain, disability, and negative affect: a systematic review and meta-analysis

Hypersensitivity due to central pain mechanisms can influence recovery and lead to worse clinical outcomes, but the ability of quantitative sensory testing (QST), an index of sensitisation, to predict outcomes in chronic musculoskeletal disorders remains unclear. We systematically reviewed the evidence for ability of QST to predict pain, disability, and negative affect using searches of CENTRAL, MEDLINE, EMBASE, AMED, CINAHL, and PubMed databases up to April 2018. Title screening, data extraction, and methodological quality assessments were performed independently by 2 reviewers. Associations were reported between baseline QST and outcomes using adjusted (β) and unadjusted (r) correlations. Of the 37 eligible studies (n = 3860 participants), 32 were prospective cohort studies and 5 randomised controlled trials. Pain was an outcome in 30 studies, disability in 11, and negative affect in 3. Meta-analysis revealed that baseline QST predicted musculoskeletal pain (mean r = 0.31, 95% confidence interval [CI]: 0.23-0.38, n = 1057 participants) and disability (mean r = 0.30, 95% CI: 0.19-0.40, n = 290 participants). Baseline modalities quantifying central mechanisms such as temporal summation and conditioned pain modulation were associated with follow-up pain (temporal summation: mean r = 0.37, 95% CI: 0.17-0.54; conditioned pain modulation: mean r = 0.36, 95% CI: 0.20-0.50), whereas baseline mechanical threshold modalities were predictive of follow-up disability (mean r = 0.25, 95% CI: 0.03-0.45). Quantitative sensory testing indices of pain hypersensitivity might help develop targeted interventions aiming to improve outcomes across a range of musculoskeletal conditions.

Pain neuroscience education plus exercise compared with exercise in university students with chronic idiopathic neck pain

Background/Aims

Neck pain is a common complaint. Its prevalence is particularly high in university students. This study examined the effects of pain neuroscience education plus exercise when compared with exercise only in university students with chronic idiopathic neck pain.

Methods

University students with chronic neck pain were randomly allocated to receive pain neuroscience education plus exercise, or exercise only intervention, and assessed at baseline, after the intervention and at 3-month follow-up. Pain intensity (primary outcome), disability, fear of movement, catastrophising, knowledge of pain neurophysiology, pressure pain thresholds and neck and scapular muscle endurance were measured to determine the impact of the interventions.

Results

It was found that disability (F=17.3, P<0.001; partial eta2=0.48), fear of movement (F=5.3, P=0.009; partial eta2=0.22), catastrophising (F=16.4, P<0.001; partial eta2=0.48) and neck extensor endurance (F=11.0, P=0.002; partial eta2=0.19) changed significantly over time. There was a significant increase in neurophysiology of pain questionnaire score for the group receiving pain neuroscience education plus exercise but not for the group receiving exercise only (group vs time interaction: F=19.8, P<0.001; partial eta2=0.51). No other significant differences were found.

Conclusions

Pain neuroscience education plus exercise has comparable results to exercise only, with the exception of knowledge about pain neurophysiology. The impact of this difference needs to be explored in future studies.

Effectiveness and tolerability of THC:CBD oromucosal spray as add-on measure in patients with severe chronic pain: analysis of 12-week open-label real-world data provided by the German Pain e-Registry

Objective: To evaluate effectiveness, tolerability and safety of an oromucosal spray containing Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), as add-on treatment in patients with severe chronic pain (SCP).

Methods: Exploratory analysis of anonymized 12-week routine/open-label data provided by the German Pain e-Registry (GPR) on adult SCP patients treated with THC:CBD oromucosal spray in 2017.

Results: Among those 30.228 cases documented in the GPR in 2017, 800 (2.6%; 57% female, mean ± SD age: 46.3±9.7 years) received a treatment with THC:CBD. All patients fulfilled the legislative preconditions for a treatment with cannabis as medicine as defined by the German Act Amending Narcotics and Other Regulations. THC:CBD-treatment was followed by an aggregated nine-factor symptom relief (ASR-9) improvement at end of week 12 vs baseline of 39.0±26.5% (95%-CI: 36.9–41.1, median: 42, range −41 to 85). A full ASR-9 response (ie, a 50%-improvement in all 9 factors) was found for 123 patients (15.4%), while 488 patients (56.0%) presented with an ≥50% improvement in at least 5 of 9 ASR factors. With a 54.9±17.2% (median: 56%, range: −6 to 85) improvement was significantly superior in the neuropathic pain subgroup (n=497, 62.1%) vs those with mixed (n=249, 31.1%; ASR-9: 18.2±12.0, median: 19, range: −12 to 42%) or nociceptive pain (n=54, 6.8%; ASR-9: −11.9±10.5, median: −11, range: −41% to 12%; p<0.001 for each). 159 patients (19.9%) reported at least one of 206 TEAEs, most of them of mild intensity (n=81.6%). Most frequently reported TEAEs were increased appetite (n=50, 6.3%) and dysgeusia (n=23, 2.9%). TEAE-related discontinuations were reported for 32 patients (4.0%). 113 (14.1%) patients discontinued due to inadequate pain relief, most of them with nociceptive pain (n=40, 74.1%), least with neuropathic pain (n=1, 0.2%; p<0.001).

Conclusion: THC:CBD oromucosal spray proved to be an effective and well-tolerated add-on treatment for patients with elsewhere refractory chronic pain – especially of neuropathic origin.

Measures of central sensitisation and their measurement properties in the adult musculoskeletal trauma population: a protocol for a systematic review and data synthesis

INTRODUCTION

Pain following musculoskeletal trauma is common with poor outcomes and disability well documented. Pain is complex in nature and can include the four primary mechanisms of pain: nociceptive, neuropathic, inflammatory and central sensitisation (CS). CS can be measured in multiple ways; however, no systematic review has evaluated the measurement properties of such measures in the musculoskeletal trauma population. This systematic review aims to evaluate the measurement properties of current measures of CS in this population.

METHODS/ANALYSIS

This protocol is informed and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis-P. MEDLINE, EMBASE, CINAHL, ZETOC, Web of Science, PubMed and Google Scholar as well as key journals and grey literature will be searched in two stages to (1) identify what measures are being used to assess CS in this population and (2) evaluate the measurement properties of the identified measures. Two independent reviewers will conduct the search, extract the data, assess risk of bias for included studies and assess overall quality. The Consensus-based Standards for the selection of Health Measurement Instruments Risk of Bias Checklist and a modified Grading of Recommendations, Assessment, Development and Evaluation guidelines will be used. Meta-analysis will be conducted if deemed appropriate. Alternatively, a narrative synthesis will be conducted and summarised per measurement property per outcome measure.

ETHICS AND DISSEMINATION

This review will aid clinicians in using the most appropriate tool for assessing central sensitisation in this population and is the first step towards a more standardised approach in pain assessment. The results of this study will be submitted to a peer reviewed journal and presented at conferences.

PROSPERO REGISTRATIONNUMBER

CRD42018091531.

Difference between subjects in early chronic phase of low back pain with and without neuropathic component: observational cross-sectional study

BACKGROUND

Neuropathic pain in early chronic low back pain is insufficiently recognized and treated.

AIM

The aim of this study was to establish if there is a difference among chronic low back pain subjects with and without neuropathic pain and healthy subjects, in clinical characteristic and the level of trunk muscle activation.

DESIGN

Cross sectional observational study.

SETTING

Rehabilitation clinic, inpatient and outpatient.

POPULATION

Thirty-three subjects in early chronic phase of low back pain and 26 healthy subjects were included in this research.

METHODS

Clinical characteristics and relative thickness change of lumbar multifidus and transversal abdominal muscle, measured by ultrasound, in neuropathic, non-neuropathic chronic low back pain and healthy subjects were analyzed.

RESULTS

Chronic low back pain subjects with neuropathic pain reported higher level of pain on Visual Analog Scale (VAS) (back pain P=0.016, leg pain P=0.006), had higher Oswestry Disability Score (P=0.029), had lower motor (P=0.001) and sensory leg scores (P=0.000), and decreased level of activation of transversal abdominal muscle (P=0.000) comparing to chronic low back pain group without neuropathic pain. Low back pain subjects with leg pain ≥5 on VAS were 11.2 times more prone to develop neuropathic pain. Motor leg score ≤47 increases this chance 35 times. Sensory leg score ≤25 increases this chance 14 times. Reduced activation of transversal abdominal muscle for 40-50% increases this chance 7-24 times.

CONCLUSIONS

Chronic low back pain subjects with neuropathic pain were more painful and disabled, had lower motor and sensory scores, and lower relative thickness change of transversal abdominal muscle comparing to the low back pain group without neuropathic pain. Self -reported leg pain intensity of 5 or more on VAS, motor score of 47 and less, sensory scores of 25 and less and diminished activation of transversal abdominal muscle significantly increase the chance that chronic low back pain subject has neuropathic component of pain.

CLINICAL REHABILITATION IMPACT

Neuropathic pain in early chronic low back pain subjects might be more readily recognized if patients with radiculopathy and diminished activation of transversal abdominal muscle were regularly screened for neuropathic pain.

Pharmacological target therapy of neuropathic pain and patient-reported outcomes in patients with chronic low back pain in Korea: Results from the NLBP Outcomes Research

A number of studies have demonstrated an association of neuropathic pain and chronic low back pain (CLBP), but the outcome difference in each medical management is poorly understood. This study is aimed to investigate treatment patterns of neuropathic pain in CLBP patients and to explore patient-reported outcomes (PROs) including quality of life (QoL) and functional disability by treatment patterns.Data were extracted from the neuropathic low back pain (NLBP) outcomes research. It was a multicenter and cross-sectional study in which 1200 patients were enrolled at 27 general hospitals, from 2014 to 2015. Of total, 478 patients classified as neuropathic pain were used for this subgroup analysis. The patients were divided into 2 groups according to treatment patterns (with vs. without the targeted therapy [TT] of neuropathic pain). Demographic and clinical features were collected by chart reviews and PROs were measured by patient's survey. QoL was assessed by EuroQoL 5-dimension (EQ-5D) questionnaire. Functional disability was measured by the Quebec Back Pain Disability Scale (QBPDS). Multiple linear regression analyses were conducted to compare the PROs between TT group and non-targeted therapy (nTT) group.Among the NLBP patients (mean age 63years, female 62%), EQ-5D index, EuroQoL-Visual Analog Scale (EQ-VAS), and QBPDS Scores (mean ± standard deviation) were 0.40 ± 0.28, 54.98 ± 19.98, and 46.03 ± 21.24, respectively. Only 142 (29.7%) patients had pharmacological TT of neuropathic pain. Univariate analyses revealed no significant mean differences between TT group and nTT group in the EQ-5D index (0.41 ± 0.27 and 0.39 ± 0.28), EQ-VAS (56.43 ± 18.17 and 54.37 ± 20.69), and QBPDS (45.31 ± 21.32 and 46.31 ± 21.24). After adjustment with covariates, TT group had higher scores of EQ-5D index (β = 0.07; P < 0.01) and EQ-VAS (β = 4.59; P < 0.05) than the nTT group. The TT group's QBPDS score was lower than the nTT group, although its statistical significance still has not been reached (β = -4.13; P = 0.07).We found that considerable proportion of the NLBP patients remains untreated or undertreated. Although TT group had significantly better QoL than nTT group, only 29.7% of NLBP patients had pharmacological TT. Therefore, clinicians should consider using TT for better QoL of neuropathic pain patients.