Sensory symptom profiles and co-morbidities in painful radiculopathy

Neurological examination for cervical radiculopathy: a scoping review

BACKGROUND

To diagnose cervical radiculopathy according to the International Association for the Study of Pain definition, signs of neurological deficits must be examined with the neurological examination. However, the diagnostic accuracy of the standard neurological examination remains unclear, and no clear recommendations exist about standard components. Therefore, the objectives of this review are to map the research about the diagnostic accuracy, components, and performance of the neurological examination for cervical radiculopathy.

METHOD

PubMed, Embase, Scopus, Cinhal, DiTA databases were searched up to February 23rd, 2024. Additional studies were identified through screening reference lists of the included studies. Studies on neurological examination procedures and their diagnostic accuracy for cervical radiculopathy were included.

RESULTS

From an initial 12,365 records, 6 articles met the inclusion criteria. All articles were cross-sectional studies and compared the neurological examination with electrodiagnostic tests or magnetic resonance imaging. Reduced tendon reflexes were found to be most specific (81% (95% CI 69-89%) to 99% (95% CI not reported)), while somatosensation testing was least sensitive (25% (95% CI 12-38%; -LR 0.84) to 52% (95% CI 30-74%)). Taking all components into account resulted in higher specificity (98% (95% CI not reported) to 99% (95% CI 95-100%)) but lower sensitivity (7% (95% CI not reported) to 14% (95% CI 5-16%)) compared to electrodiagnostic tests.

CONCLUSIONS

We found varying operational definitions of radiculopathy, suboptimal reference standards, and great heterogeneity in the neurological examination procedure and its diagnostic accuracy. Future research should address these issues to establish the clinical utility of the neurological examination for cervical radiculopathy.

PROTOCOL

https://doi.org/10.1101/2023.05.22.23290194 .

[Retrospective evaluation of electronically recorded patient questionnaires of a university outpatient pain clinic with the painDETECT® questionnaire]

BACKGROUND AND OBJECTIVE

Psychometric tests can provide important information for diagnostics and progression in chronic pain patients. Between 2008 and 2018, the electronic system painDETECT® was used in the outpatient pain clinic of the Hannover Medical School (MHH). The aim of this retrospective study was to evaluate the pain symptomatology data recorded using painDETECT® and the treatment procedures used in the patient cohort examined over a period of 15 months.

MATERIAL AND METHODS

A statistical analysis of baseline and follow-up data was performed. The analysis comprised pain-related parameters recorded by use of the painDETECT® system as well as outpatient records.

RESULTS

Baseline data of 459 patients (66% women) could be evaluated. The most common clinical pictures were spinal pain, headache, facial pain, and somatoform disorders, mostly with many years of previous treatment. Approximately 40% showed evidence of neuropathic pain components or central sensitization. With a mean pain intensity of VAS 6 (0-10), a predominantly high degree of chronicity was present. Approximately one third showed a high degree of pain-related functional impairment. Slightly more than half showed evidence of clinically relevant depression. Approximately 80% showed clinically relevant sleep disturbances. Follow-up data were available for 145 patients (31.6%). The proportion of patients receiving a nonpharmacological form of treatment increased by 44.1% (physical therapy) and by 24.1% (psychotherapeutic procedures) during the observation period. The use of co-analgesics increased by approximately 30% over the course.

CONCLUSION

In the outpatient setting, an extension of treatment can be successful for high-grade chronic pain patients. Close structural networking with the clinics for rehabilitation medicine and for psychosomatics and psychotherapy at the MHH can be a favorable prerequisite for this.

Association of nociplastic and neuropathic pain components with the presence of residual symptoms in patients with axial spondyloarthritis receiving biological disease-modifying antirheumatic drugs

OBJECTIVE

To evaluate the association of nociplastic (NoP) and neuropathic pain (NP) components with residual symptoms in patients with radiographic axial spondyloarthritis (r-axSpA) receiving biological disease-modifying antirheumatic drugs (bDMARDs).

METHODS

78 patients with r-axSpA from the GErman SPondyloarthritis Inception Cohort receiving a bDMARD for at least 3 months were included in this analysis. The Widespread Pain Index (WPI) and the PainDETECT (PD) questionnaire were used to quantify the NoP and the NP components, respectively. Axial Spondyloarthritis Disease Activity Score (ASDAS) and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) were used as measures of residual symptoms. C reactive protein (CRP) was used as a measure of systemic inflammatory activity. Univariable and multivariable regression analyses of disease activity were performed. The regions of the WPI score and items of the PD score were used for cluster analyses.

RESULTS

Linear multivariable regression analysis showed that WPI and PD were independently associated with ASDAS (b=0.1, 95% CI 0.04 to 0.17, and b=0.05, 95% CI 0.02 to 0.08, respectively) and BASDAI (b=0.24, 95% CI 0.08 to 0.39, and b=0.17, 95% CI 0.1 to 0.25, respectively) in r-axSpA patients receiving stable treatment with bDMARDs. Furthermore, WPI and PD were found to be significantly associated with the presence of relevant residual symptoms as defined by BASDAI ≥4 (OR 1.93, 95% CI 1.09 to 4.15, and OR 1.32, 95% CI 1.04 to 1.85, respectively). The effects were present also in patients with normal level of CRP. Cluster analysis revealed three distinct pain distribution profiles and four specific sensory symptom constellations allowing differentiation of different pain subtypes.

CONCLUSION

Both NoP and NP components seem to be associated with residual symptoms in patients with r-axSpA receiving treatment with bDMARDs.

Integrating jigsaw puzzle thinking into practice: the assessment of cervical spine radiculopathy

PURPOSE OF REVIEW

Cervical spine radiculopathy (CSR) presents a complex socioeconomic problem for patients, clinicians, families, employers and healthcare systems. Due to the heterogeneity of clinical presentation and underlying mechanisms, clinical assessment can be challenging. This review will examine the literature on the underlying pathophysiology and studies investigating the holistic assessment strategies for this disabling condition. The authors will focus particular attention on the psychological factors associated with CSR and the physical and imaging strategies to establish a diagnosis.

RECENT FINDINGS

Contemporary CSR assessment should identify the underlying pathomechanisms and how this may impact the somatosensory nervous system integrity and function. No physical assessment test in isolation will establish CSR diagnosis; therefore, clinicians should utilise a cluster of tests and recognise the potential limitations as part of a clinical reasoning framework. The assessment of the somatosensory nervous system can provide insights into particular subgroups of CSR presentation, which may provide interesting opportunities to continue to enhance individualised assessment and management strategies for CSR. The interplay between psychological factors can influence the diagnosis and recovery times for a person with CSR, and clinicians should continue to explore how these factors may influence a person's prognosis. The authors will discuss the opportunities for future research and limitations of contemporary approaches to assessment, underpinned by evidence, and how this supports a clinical assessment to establish CSR diagnosis.

SUMMARY

Research should continue to investigate how clinicians assess the interplay between physical and psychological factors to inform the establishment of CSR. Specifically, there is a need to investigate the validity and reliability of combining somatosensory, motor and imaging assessment findings to reach a diagnosis and inform onward management plans.

Recommendations for terminology and the identification of neuropathic pain in people with spine-related leg pain. Outcomes from the NeuPSIG working group

ABSTRACT

Pain radiating from the spine into the leg is commonly referred to as "sciatica," "Sciatica" may include various conditions such as radicular pain or painful radiculopathy. It may be associated with significant consequences for the person living with the condition, imposing a reduced quality of life and substantial direct and indirect costs. The main challenges associated with a diagnosis of "sciatica" include those related to the inconsistent use of terminology for the diagnostic labels and the identification of neuropathic pain. These challenges hinder collective clinical and scientific understanding regarding these conditions. In this position paper, we describe the outcome of a working group commissioned by the Neuropathic Pain Special Interest Group (NeuPSIG) of the International Association for the Study of Pain (IASP) which was tasked with the following objectives: (1) to revise the use of terminology for classifying spine-related leg pain and (2) to propose a way forward on the identification of neuropathic pain in the context of spine-related leg pain. The panel recommended discouraging the term "sciatica" for use in clinical practice and research without further specification of what it entails. The term "spine-related leg pain" is proposed as an umbrella term to include the case definitions of somatic referred pain and radicular pain with and without radiculopathy. The panel proposed an adaptation of the neuropathic pain grading system in the context of spine-related leg pain to facilitate the identification of neuropathic pain and initiation of specific management in this patient population.

Factors predicting the transition from acute to persistent pain in people with 'sciatica': the FORECAST longitudinal prognostic factor cohort study protocol

INTRODUCTION

Sciatica is a common condition and is associated with higher levels of pain, disability, poorer quality of life, and increased use of health resources compared with low back pain alone. Although many patients recover, a third develop persistent sciatica symptoms. It remains unclear, why some patients develop persistent sciatica as none of the traditionally considered clinical parameters (eg, symptom severity, routine MRI) are consistent prognostic factors.The FORECAST study (factors predicting the transition from acute to persistent pain in people with 'sciatica') will take a different approach by exploring mechanism-based subgroups in patients with sciatica and investigate whether a mechanism-based approach can identify factors that predict pain persistence in patients with sciatica.

METHODS AND ANALYSIS

We will perform a prospective longitudinal cohort study including 180 people with acute/subacute sciatica. N=168 healthy participants will provide normative data. A detailed set of variables will be assessed within 3 months after sciatica onset. This will include self-reported sensory and psychosocial profiles, quantitative sensory testing, blood inflammatory markers and advanced neuroimaging. We will determine outcome with the Sciatica Bothersomeness Index and a Numerical Pain Rating Scale for leg pain severity at 3 and 12 months.We will use principal component analysis followed by clustering methods to identify subgroups. Univariate associations and machine learning methods optimised for high dimensional small data sets will be used to identify the most powerful predictors and model selection/accuracy.The results will provide crucial information about the pathophysiological drivers of sciatica symptoms and may identify prognostic factors of pain persistence.

ETHICS AND DISSEMINATION

The FORECAST study has received ethical approval (South Central Oxford C, 18/SC/0263). The dissemination strategy will be guided by our patient and public engagement activities and will include peer-reviewed publications, conference presentations, social media and podcasts.

TRIAL REGISTRATION NUMBER

ISRCTN18170726; Pre-results.

Multisensory sensitivity differentiates between multiple chronic pain conditions and pain-free individuals

ABSTRACT

Multisensory sensitivity (MSS) to nonpainful stimuli has been identified as a risk factor for the presence of coexisting chronic pain conditions. However, it remains unclear whether MSS can differentiate pain phenotypes involving different levels of central sensitivity. Both pain-free and those with chronic pain, particularly fibromyalgia (FM), migraine, or low back pain (LBP) were recruited, with pain comorbidities assessed. MSS was highest in FM, followed by migraine, then LBP, and lowest in pain-free individuals (adjusted between condition Cohen d = 0.32-1.2, P ≤ 0.0007). However, when secondly grouping patients by the total number of pain comorbidities reported, those with a single pain condition (but not FM) did not have significantly elevated MSS vs pain-free individuals (adj d= 0.17, P = 0.18). Elevated MSS scores produced increased odds of having 2 or more pain comorbidities; OR [95% CI] =2.0 [1.15, 3.42], without, and 5.6 [2.74, 11.28], with FM ( P ≤ 0.0001). Furthermore, those with low MSS levels were 55% to 87% less likely to have ≥ 2 pain comorbidities with or without FM (OR 0.45 [0.22, 0.88]-0.13 [0.05, 0.39]; P ≤ 0.0001). Our findings support that MSS can differentiate between pain phenotypes with different degrees of expected central mechanism involvement and also serve as a risk and resilience marker for total coexisting chronic pain conditions. This supports the use of MSS as a marker of heightened central nervous system processing and thus may serve as a clinically feasible assessment to better profile pain phenotypes with the goal of improving personalized treatment.

Precision Medicine in Neuropathic Pain

Neuropathic pain is a common chronic pain condition that is caused by a lesion or disease of the somatosensory nervous system. The multitude of sensory negative and positive sensations and associated comorbidities have a major impact on quality of life of affected patients. Current treatment options often only lead to a partial pain relief or are even completely ineffective. In addition, many clinical trials for the development of new drugs have not met the primary endpoint. Therefore, there is still an unmet clinical need in neuropathic pain syndromes. One reason for this therapeutic dilemma could be the heterogeneity of neuropathic pain with a variety of pathophysiological pain mechanisms that are expressed differently in each patient regardless of the underlying disease etiology. Reclassification of neuropathic pain syndromes therefore focuses on the underlying mechanisms of pain development rather than the disease etiology. A priori stratification of patients based on these individual mechanisms could allow the identification of potential treatment responders and thus realize the concept of a mechanism-based treatment. As no biomarkers for pain mechanisms have been discovered yet, one has to rely on surrogate markers that are thought to be closely related to these mechanisms. In this chapter, we present promising predictive biomarkers, focusing in particular on sensory symptoms and signs assessed by patient-reported outcome measures and sensory testing, and discuss how these tools might be used in clinical trials in the future.

Subgrouping patients with zoster-associated pain according to sensory symptom profiles: A cluster analysis

Background and goal of study

Patients with zoster-associated pain exhibit a variety of sensory symptoms and forms of pain and complain of different pain patterns. The purpose of this study is to subgroup patients with zoster-associated pain who visited a hospital using painDETECT sensory symptom scores, analyze their respective characteristics and pain-related data, and compare similarities and differences among the groups.

Materials and methods

The characteristics of 1,050 patients complaining of zoster-associated pain and pain-related data were reviewed retrospectively. To identify subgroups of patients with zoster-associated pain according to sensory symptom profiles, a hierarchical cluster analysis was performed based on the responses to a painDETECT questionnaire. Demographics and pain-related data were compared among all subgroups.

Results and discussion

Patients with zoster-associated pain were classified into 5 subgroups according to the distribution of sensory profiles, with each subgroup exhibiting distinct differences in the expression of sensory symptoms. Patients in cluster 1 complained of burning sensations, allodynia, and thermal sensitivity, but felt numbness less strongly. Cluster 2 and 3 patients complained of burning sensations and electric shock-like pain, respectively. Cluster 4 patients complained of most sensory symptoms at similar intensities and reported relatively strong prickling pain. Cluster 5 patients suffered from both burning and shock-like pains. Patient ages and the prevalence of cardiovascular disease were significantly lower in cluster 1. Patients in clusters 1 and 4 reported longer pain duration compared with those in clusters 2 and 3. However, no significant differences were found with respect to sex, body mass index, diabetes mellitus, mental health problems, and sleep disturbance. Pain scores, distribution of dermatomes and gabapentinoid use were also similar among the groups.

Conclusions

Five different subgroups of patients with zoster-associated pain were identified on the basis of sensory symptoms. A subgroup of younger patients with longer pain duration showed specific and distinct symptoms, such as burning sensations and allodynia. Unlike patients with acute or subacute pain, patients with chronic pain were associated with diverse sensory symptom profiles.

Symptom descriptors and patterns in lumbar radicular pain caused by disc herniation: a 1-year longitudinal cohort study

OBJECTIVE

The objective of the present study was to explore the diversity, quality, severity and distribution of symptoms in patients with radicular pain and a lumbar disc herniation.

DESIGN

Longitudinal cohort study.

SETTING

Hospital-based back clinic.

PARTICIPANTS

Ninety patients referred to secondary healthcare with (a) low back-related leg pain, (b) age between 18 and 65 years and (c) MRI confirmed lumbar disc herniation at a relevant side and level.

OUTCOME MEASURES

Neuropathic pain symptoms were assessed using the Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2) and the painDETECT Questionnaire. In a subsample classified with neuropathic pain, in-depth interviews were performed, and symptomatic areas were drawn on standardised body charts.

RESULTS

At baseline, the most frequently used painDETECT symptom descriptor was numbness sensation, reported by 94%, followed by sudden pain attacks and tingling or prickling. The mean (SD) SF-MPQ-2 score (0-10) for aching pain was 5.9 (2.8); numbness 4.3 (3.3); tingling 4.0 (3.4); burning 2.6 (3.1); pain caused by light touch 1.5 (2.6). Leg pain was rated as extremely bothersome by 73%, numbness and tingling by 38%, weakness by 24% and back pain by 17%. In the subsample (n=52), deep-lying pain and non-painful abnormal sensations were frequent, at 71% and 85%. Drawings demonstrated substantial overlap between symptoms from compromised L5 and the S1 nerve roots. Painful and non-painful symptoms improved at approximately the same rate. At the 1-year follow-up, 45% (14/31) of patients who had received disc surgery, and 34% (18/53) of those who had received conservative treatment reported no bothersome back pain, leg pain, numbness/tingling or weakness.

CONCLUSION

Patients reported several highly bothersome symptoms, but not all are described as painful. The overall symptom profile of lumbar disc-related radicular pain differs from other neuropathic pain conditions with limited allodynia and thermal hyperalgesia. Symptomatic areas for the L5 and S1 nerve roots have a large overlap.

[Quantitative sensory testing for neuropathic pain and its relevance for physiotherapy]

BACKGROUND

Neuropathic pain syndromes are typically characterized by high chronification rates as well as long and intensive pain episodes. Early and accurate diagnosis of neuropathic pain is a basic skill of physiotherapists and other medical professionals, may allow for appropriate medical treatment and help to prevent possible consequential damage. Quantitative sensory testing (QST) can be applied as a supplement to conventional neurological bedside testing in the evaluation of neuropathic pain. Over recent decades, QST has come to hold a significant position in the field of pain research. However, despite these developments, the application of QST in clinical practice has lagged behind.

OBJECTIVES

What is the value of QST in the study of neuropathic pain? Have the conditions for personal clinical use of the QST been established in physiotherapy practice? Have the pathways for specific implementation of the QST been defined?

METHOD

Literature research as part of a Bachelor thesis in Physiotherapy.

RESULTS

QST constitutes a valid examination tool that is able to evaluate the complete somatosensory profile. In this way, QST may provide substantial additional benefit in the examination of neuropathic pain patients compared to other conventional testing procedures, especially when it comes to small-fibre neuropathies. These small fibres seem to be particularly affected in asymptomatic patients as well as early phases of neuropathies and cannot be investigated via conventional testing procedures. This makes the use of partial aspects of the QST a proven instrument for physiotherapists and medical staff, which was particularly useful in the decision-making process for neuropathies.

DISCUSSION

Nonetheless, regarding the results, there are still several limiting factors that hamper the routine use of QST. Some of these can be resolved by precisely adhering to testing protocols and taking precautions. Other highly relevant issues for clinical practice, such as the immense cost of equipment and the excessive time required for testing, have not been satisfactorily overcome as yet. Less comprehensive testing protocols as well as the innovation of handy and cost-effective testing devices might offer initial approaches to enhance the widespread use of QST. Complementing conventional bedside testing by adding thermal discrimination tests and pain detection threshold tests might prove to be another possibility to integrate the benefit of QST into clinical practice.

CONCLUSION

QST makes a significant contribution to the investigation and diagnosis of neuropathies. Physiotherapists are encouraged to implement partial aspects of the QST in a standard examination in order to have a positive effect on both early detection and treatment.

Questionnaire-based somatosensory profiling in breast cancer survivors: are we there yet? Associations between questionnaires and quantitative sensory testing

PURPOSE

Pain and sensory disturbances are common side effects of breast cancer treatment. Differential somatosensory functioning may reflect distinct pathophysiological backgrounds and therapeutic needs. Aim was to examine whether questionnaires evaluating signs and symptoms related to somatosensory functioning correlate sufficiently with quantitative sensory testing (QST) in breast cancer survivors to warrant consideration for somatosensory profiling in clinical practice.

METHODS

One year after breast cancer surgery, 147 women underwent QST and completed following questionnaires: Douleur Neuropathique en 4 questions (DN4), Central Sensitization Inventory, Margolis Pain Diagram and Visual Analog Scales (VAS). Associations between the questionnaires and QST were evaluated using Spearman correlation coefficients (rs).

RESULTS

Significant but weak (rs < 0.30) correlations were found between total DN4 score and QST results at the inner upper arm for detection of sharp stimuli (rs = 0.227), cold stimuli (rs = -0.186), and painful heat stimuli (rs = 0.179), as well as between QST evaluating conditioned pain modulation and the Margolis Pain Diagram on one hand (rs = 0.176) and minimum-maximum pain intensity differences (VAS) on the other (rs = -0.170).

CONCLUSION

Questionnaires evaluating signs and symptoms related to somatosensory functioning are insufficient for somatosensory profiling. Although somatosensory profiling may be valuable in a mechanism-based management, more research on the most appropriate clinical tools is needed.IMPLICATIONS FOR REHABILITATIONClinicians should be able to recognize that patients with persistent pain or sensory disturbances following breast cancer surgery may have a component of altered somatosensory processing as a significant contributor to their complaint in order to address it appropriately.Somatosensory profiling has yet to be implemented into clinical practice.No evidence-based recommendations can be made on the use of self-reported questionnaires to assess somatosensory processing in a breast cancer population based on the findings of this study.It is suggested to combine information on how individuals process and experience somatosensory stimulation with information from the patient interview or questionnaires to consider which biological, psychological and/or social factors may drive or sustain these neurophysiological processes.

Is There a Neuropathic-Like Component to Endometriosis-Associated Pain? Results From a Large Cohort Questionnaire Study

Background: Pain is one of the primary symptoms of endometriosis, a chronic inflammatory condition characterised by the presence of endometrial tissue outside the uterus. Endometriosis-associated pain is commonly considered as nociceptive in nature, but its clinical presentation suggests that it might have neuropathic-like properties in a subgroup of patients.

Methods: This is a cross sectional study using an online survey. The survey was distributed by patient support websites. The survey was composed of validated questionnaires assessing pain symptoms, psychological measures and questions about number of surgeries.

Main Results: We had 1,417 responses which met the inclusion criteria. Using standard painDETECT cut-off scores, we found that pain was classified as neuropathic in 40% of patients and as mixed neuropathic/nociceptive in a further 35%. In line with observations in other neuropathic conditions, the neuropathic subgroup reported higher pain intensities, greater psychological distress and cognitive impairment. Neuropathic pain was also more likely in those with more surgeries to the abdomen and a longer history of pain. As revealed by a cluster analysis, those with a neuropathic pain component could further be divided into two subgroups based on their sensory profile.

Conclusions: The data presented here indicate that endometriosis-associated pain includes a neuropathic-like component in a substantial proportion of women. Although further investigation is required, our finding challenges the current conceptualisation of endometriosis-associated pain as nociceptive and advocates for a new perspective on this type of pain, which is so debilitating to a large number of women.

Development of a clinical prediction model to inform clinical decision making for classification of patients with sciatica, based on their clinical characteristics, in the Greek health system: protocol for a prospective predictive exploratory study

INTRODUCTION

Sciatica is one of the most common reasons for seeking healthcare for musculoskeletal pain. Sciatica is primarily considered as neuropathic in nature when neural tissue in the low back is compromised, but sometimes other non-neural structures may be involved. Appropriate assessment and management are important for patients with sciatica. Therapists use several outcome measures to assess patients to inform selection of the most suitable treatment. There is limited evidence for the best treatment of sciatica, and this is likely contributed to by having no reliable algorithm to categorise patients based on their clinical characteristics to inform physiotherapy treatment. The purpose of this study is to develop a clinical prediction model to categorise patients with sciatica, in terms of early clinical outcome, based on their initial clinical characteristics.

METHODS AND ANALYSIS

A prospective observational multicentre design will recruit consecutive patients (n=467) with sciatica referred for physiotherapy. Each patient will be evaluated to determine whether or not they will be accepted into the study by answering some questions that will confirm the study's eligibility criteria. Patients' basic characteristics, patient-reported outcome measures and performance-based measures will be collected at baseline from multiple sites in the Greek territory using this same protocol, prior to commencement of treatment. The main researcher of this study will be responsible for data collection in all sites. On completion of the standard referred physiotherapy treatment after 3 weeks' time, participants will be asked by telephone to evaluate their outcome using the Global Perceived Effect Scale. For the descriptive statistical analysis, the continuous variables will be expressed in the form of 'mean' and 'SD'. In order to assess the prognostic value of each predictor, in terms of the level of improvement or worsening of the symptoms, multiple variable regression analysis will be used.

ETHICS AND DISSEMINATION

Τhis study is approved from the Ethics and Deontology Committee of the University of West Attica, Athens, Greece, protocol number: 38313-09/06/2020, 10226-10/02/2021. The study's findings will be published in a peer-reviewed journal and disseminated at national and international conferences and through social media.

PROSPERO REGISTRATION NUMBER

CRD42020168467.

Subgrouping of Peripheral Neuropathic Pain Patients According to Sensory Symptom Profile Using the Korean Version of the PainDETECT Questionnaire

BACKGROUND

A culturally validated Korean version of the PainDETECT Questionnaire (PD-Q) was used to identify neuropathic pain components (NeP) in patients suffering from chronic pain. The purpose of this study was to determine if the Korean PD-Q can be used to subgroup patients with peripheral NeP according to sensory symptom profiles.

METHODS

This study included 400 Korean patients with peripheral neuropathic pain diagnosed as probable or definite NeP. The total scores and subscores for each item in PD-Q were transformed into a Z-score for standardization. Hierarchical cluster analysis was performed to identify clusters of subjects by PD-Q scores.

RESULTS

The mean total PD-Q score of the study participants was 14.57 ± 6.46. A hierarchical cluster analysis identified 5 clusters with distinct pain characteristic profiles. Cluster 1 had relatively severe burning and tingling sensations. The mean total PD-Q score for cluster 2 was the lowest of the 5 clusters. Cluster 3 tended to be vulnerable to pain in response to cold/heat stimulation. Cluster 4 showed relatively severe pain induced by physical stimuli, such as light touch or slight pressure. Cluster 5 had high scores for all NeP symptoms.

CONCLUSION

This study demonstrates the ability of patients to cluster by symptoms using the Korean PD-Q. Subgrouping of peripheral neuropathic pain by sensory symptom profile may be useful in making effective drug treatment decisions.

[Entrapment neuropathies: a contemporary approach to pathophysiology, clinical assessment, and management : German version]

Entrapment neuropathies such as carpal tunnel syndrome, radiculopathies, or radicular pain are the most common peripheral neuropathies and also the most common cause for neuropathic pain. Despite their high prevalence, they often remain challenging to diagnose and manage in a clinical setting. Summarising the evidence from both preclinical and clinical studies, this review provides an update on the aetiology and pathophysiology of entrapment neuropathies. Potenzial mechanisms are put in perspective with clinical findings. The contemporary assessment is discussed and diagnostic pitfalls highlighted. The evidence for the noninvasive and surgical management of common entrapment neuropathies is summarised and future areas of research are identified.

Differential response to scrambler therapy by neuropathic pain phenotypes

Scrambler therapy is a noninvasive electroanalgesia technique designed to remodulate the pain system. Despite growing evidence of its efficacy in patients with neuropathic pain, little is known about the clinical factors associated with treatment outcome. We conducted a prospective, open-label, single-arm trial to assess the efficacy and safety of scrambler therapy in patients with chronic neuropathic pain of various etiologies. A post-hoc analysis was performed to investigate whether cluster analysis of the Neuropathic Pain Symptom Inventory (NPSI) profiles could identify a subgroup of patients regarding neuropathic pain phenotype and treatment outcome. Scrambler therapy resulted in a significant decrease in the pain numerical rating scale (NRS) score over 2 weeks of treatment (least squares mean of percentage change from baseline, − 15%; 95% CI − 28% to − 2.4%; p < 0.001). The mean score of Brief Pain Inventory (BPI) interference subdimension was also significantly improved (p = 0.022), while the BPI pain composite score was not. Hierarchical clustering based on the NPSI profiles partitioned the patients into 3 clusters with distinct neuropathic pain phenotypes. Linear mixed-effects model analyses revealed differential response to scrambler therapy across clusters (p = 0.003, pain NRS; p = 0.072, BPI interference subdimension). Treatment response to scrambler therapy appears different depending on the neuropathic pain phenotypes, with more favorable outcomes in patients with preferentially paroxysmal pain rather than persistent pain. Further studies are warranted to confirm that capturing neuropathic pain phenotypes can optimize the use of scrambler therapy.

"Shooting pain" in lumbar radiculopathy and trigeminal neuralgia, and ideas concerning its neural substrates

Patients with radicular low back pain (radicular LBP, sciatica) frequently describe their pain as "shooting" or "radiating." The dictionary meaning of these words implies rapid movement, and indeed, many sufferers report feeling pain moving rapidly from the lower back or buttock into the leg. But, others do not. Moreover, the sensation of movement is paradoxical; it is neither predicted nor accounted for by current ideas about the pathophysiology of radicular LBP. We have used a structured questionnaire to evaluate the sensory qualities associated with "shooting" and "radiating" in 155 patients, 98 with radicular LBP and 57 with trigeminal neuralgia, a second chronic pain condition in which shooting/radiating are experienced. Results indicated a spectrum of different sensations in different people. Although many sciatica patients reported rapid downward movement of their pain, even more reported downward expansion of the area of pain, some reported upward movement, and for some, there was no spatial dynamic at all. The velocity of movement or expansion was also variable. By cross-referencing sensations experienced in the sciatica and trigeminal neuralgia cohorts with known signal processing modes in the somatosensory system, we propose testable hypotheses concerning the pathophysiology of the various vectorial sensations reported, their direction and velocity, and the structures in which they are generated. Systematic evaluation of qualitative features of "shooting" and "radiating" pain at the time of diagnosis can shed light on the pain mechanism in the individual patient and perhaps contribute to a better therapeutic outcomes.

Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations

There is tremendous interpatient variability in the response to analgesic therapy (even for efficacious treatments), which can be the source of great frustration in clinical practice. This has led to calls for “precision medicine” or personalized pain therapeutics (ie, empirically based algorithms that determine the optimal treatments, or treatment combinations, for individual patients) that would presumably improve both the clinical care of patients with pain and the success rates for putative analgesic drugs in phase 2 and 3 clinical trials. However, before implementing this approach, the characteristics of individual patients or subgroups of patients that increase or decrease the response to a specific treatment need to be identified. The challenge is to identify the measurable phenotypic characteristics of patients that are most predictive of individual variation in analgesic treatment outcomes, and the measurement tools that are best suited to evaluate these characteristics. In this article, we present evidence on the most promising of these phenotypic characteristics for use in future research, including psychosocial factors, symptom characteristics, sleep patterns, responses to noxious stimulation, endogenous pain-modulatory processes, and response to pharmacologic challenge. We provide evidence-based recommendations for core phenotyping domains and recommend measures of each domain.

When to consider "mixed pain"? The right questions can make a difference!

The term "mixed pain" is increasingly applied for specific clinical scenarios, such as low back pain, cancer pain and postsurgical pain, in which there "is a complex overlap of the different known pain types (nociceptive, neuropathic, nociplastic) in any combination, acting simultaneously and/or concurrently to cause pain in the same body area." Whether mixed pain is the manifestation of neuropathic and nociceptive mechanisms operating simultaneously or concurrently, or the result of an entirely independent pathophysiological mechanism - distinct from nociceptive, nociplastic and neuropathic pain - is currently unknown. At present, the diagnosis of mixed pain is made based on clinical judgement following detailed history-taking and thorough physical examination, rather than by formal confirmation following explicit screening or diagnostic criteria; this lack of formalized screening or diagnostic tools for mixed pain is problematic for physicians in primary care, who encounter patients with probable mixed pain states in their daily practice. This article outlines a methodical approach to clinical evaluation of patients presenting with acute, subacute or chronic pain, and to possibly identifying those who have mixed pain. The authors propose the use of nine simple key questions, which will provide the practicing clinician a framework for identifying the predominant pain mechanisms operating within the patient. A methodical, fairly rapid, and comprehensive assessment of a patient in chronic pain - particularly one suffering from pain with both nociceptive and neuropathic components - allows validation of their experience of chronic pain as a specific disease and, importantly, allows the institution of targeted treatment.

Stratified versus usual care for the management of primary care patients with sciatica: the SCOPiC RCT

BACKGROUND

Sciatica has a substantial impact on patients and society. Current care is 'stepped', comprising an initial period of simple measures of advice and analgesia, for most patients, commonly followed by physiotherapy, and then by more intensive interventions if symptoms fail to resolve. No study has yet tested a model of stratified care in which patients are subgrouped and matched to different care pathways based on their prognosis and clinical characteristics.

OBJECTIVES

The objectives were to investigate the clinical effectiveness and cost-effectiveness of a stratified care model compared with usual, non-stratified care.

DESIGN

This was a two-parallel group, multicentre, pragmatic, 1 : 1 randomised controlled trial.

SETTING

Participants were recruited from primary care (42 general practices) in North Staffordshire, North Shropshire/Wales and Cheshire in the UK.

PARTICIPANTS

Eligible patients were aged ≥ 18 years, had suspected sciatica, had access to a mobile phone/landline, were not pregnant, were not receiving treatment for the same problem and had not had previous spinal surgery.

INTERVENTIONS

In stratified care, a combination of prognostic and clinical criteria associated with referral to spinal specialist services was used to allocate patients to one of three groups for matched care pathways. Group 1 received advice and up to two sessions of physiotherapy, group 2 received up to six sessions of physiotherapy, and group 3 was fast-tracked to magnetic resonance imaging and spinal specialist opinion. Usual care was based on the stepped-care approach without the use of any stratification tools/algorithms. Patients were randomised using a remote web-based randomisation service.

MAIN OUTCOME MEASURES

The primary outcome was time to first resolution of sciatica symptoms (six point ordinal scale, collected via text messages). Secondary outcomes (at 4 and 12 months) included pain, function, psychological health, days lost from work, work productivity, satisfaction with care and health-care use. A cost-utility analysis was undertaken over 12 months. A qualitative study explored patients' and clinicians' views of the fast-track care pathway to a spinal specialist.

RESULTS

A total of 476 patients were randomised (238 in each arm). For the primary outcome, the overall response rate was 89.3% (88.3% and 90.3% in the stratified and usual care arms, respectively). Relief from symptoms was slightly faster (2 weeks median difference) in the stratified care arm, but this difference was not statistically significant (hazard ratio 1.14, 95% confidence interval 0.89 to 1.46; p = 0.288). On average, participants in both arms reported good improvement from baseline, on most outcomes, over time. Following the assessment at the research clinic, most participants in the usual care arm were referred to physiotherapy.

CONCLUSIONS

The stratified care model tested in this trial was not more clinically effective than usual care, and was not likely to be a cost-effective option. The fast-track pathway was felt to be acceptable to both patients and clinicians; however, clinicians expressed reluctance to consider invasive procedures if symptoms were of short duration.

LIMITATIONS

Participants in the usual care arm, on average, reported good outcomes, making it challenging to demonstrate superiority of stratified care. The performance of the algorithm used to allocate patients to treatment pathways may have influenced results.

FUTURE WORK

Other approaches to stratified care may provide superior outcomes for sciatica.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN75449581.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 49. See the NIHR Journals Library website for further project information.

Sensory descriptors which identify neuropathic pain mechanisms in low back pain: a systematic review

OBJECTIVE

Descriptors provided by patients with neuropathic low back pain (NLBP) with or without spinally referred leg pain are frequently used by clinicians to help to identify the predominant pain mechanisms. Indeed, many neuropathic screening tools are primarily based on subjective descriptors to determine the presence of neuropathic pain. There is a need to systematically review and analyse the existing evidence to determine the validity of such descriptors in this cohort.

METHODS

Ten databases were systematically searched. The review adhered to PRISMA and CRD guidelines and included a risk of bias assessment using QUADAS-2. Studies were included if they contained symptom descriptors from a group of NLBP patients +/- leg pain. Studies had to include a reference test to identity neuropathic pain from other pain mechanisms.

RESULTS

Eight studies of 3099 NLBP patients were included. Allodynia and numbness were found to discriminate between NLBP and nociceptive LBP in four studies. Autonomic dysfunction, (changes in the colour or appearance of the skin), was also found to discriminate between the groups in two studies. Dysesthesia identified NLBP in 5/7 respectively. Results from studies were equivocal regarding pain described as hot/burning cold and paroxysmal pain in people with NLBP.

CONCLUSION

Subjectively reported allodynia and numbness would suggest a neuropathic pain mechanism in LBP. Dysesthesia would raise the suspicion of NLBP. More research is needed to determine if descriptors suggesting autonomic dysfunction can identify NLBP. There is poor consensus on whether other descriptors can identify NLBP.

Diagnostic utility of patient history, clinical examination and screening tool data to identify neuropathic pain in low back related leg pain: a systematic review and narrative synthesis

BACKGROUND

Low back-related leg pain (LBLP) is a challenge for healthcare providers to manage. Neuropathic pain (NP) is highly prevalent in presentations of LBLP and an accurate diagnosis of NP in LBLP is essential to ensure appropriate intervention. In the absence of a gold standard, the objective of this systematic review was to evaluate the diagnostic utility of patient history, clinical examination and screening tool data for identifying NP in LBLP.

METHODS

This systematic review is reported in line with PRISMA and followed a pre-defined and published protocol. CINAHL, EMBASE, MEDLINE, Web of Science, Cochrane Library, AMED, Pedro and PubMed databases, key journals and the grey literature were searched from inception to 31 July 2019. Eligible studies included any study design reporting primary diagnostic data on the diagnostic utility of patient history, clinical examination or screening tool data to identify NP in LBLP, in an adult population. Two independent reviewers searched information sources, assessed risk of bias (QUADAS-2) and used GRADE to assess overall quality of evidence.

RESULTS

From 762 studies, 11 studies were included. Nine studies out of the 11 were at risk of bias. Moderate level evidence supports a cluster of eight signs (age, duration of disease, paroxysmal pain, pain worse in leg than back, typical dermatomal distribution, worse on coughing/sneezing/straining, finger to floor distance and paresis) for diagnosing lumbosacral nerve root compression, demonstrating moderate/high sensitivity (72%) and specificity (80%) values. Moderate level evidence supports the use of the StEP tool for diagnosing lumbar radicular pain, demonstrating high sensitivity (92%) and specificity (97%) values.

CONCLUSIONS

Overall low-moderate level evidence supports the diagnostic utility of patient history, clinical examination and screening tool data to identify NP in LBLP. The weak evidence base is largely due to methodological flaws and indirectness regarding applicability of the included studies. The most promising diagnostic tools include a cluster of 8 patient history/clinical examination signs and the StEP tool. Low risk of bias and high level of evidence diagnostic utility studies are needed, in order for stronger recommendations to be made.

Entrapment neuropathies: a contemporary approach to pathophysiology, clinical assessment, and management

Entrapment neuropathies such as carpal tunnel syndrome, radiculopathies, or radicular pain are the most common peripheral neuropathies and also the most common cause for neuropathic pain. Despite their high prevalence, they often remain challenging to diagnose and manage in a clinical setting. Summarising the evidence from both preclinical and clinical studies, this review provides an update on the aetiology and pathophysiology of entrapment neuropathies. Potential mechanisms are put in perspective with clinical findings. The contemporary assessment is discussed and diagnostic pitfalls highlighted. The evidence for the noninvasive and surgical management of common entrapment neuropathies is summarised and future areas of research are identified.

Neuropathic Pain: From Mechanisms to Treatment

Neuropathic pain caused by a lesion or disease of the somatosensory nervous system is a common chronic pain condition with major impact on quality of life. Examples include trigeminal neuralgia, painful polyneuropathy, postherpetic neuralgia, and central poststroke pain. Most patients complain of an ongoing or intermittent spontaneous pain of, for example, burning, pricking, squeezing quality, which may be accompanied by evoked pain, particular to light touch and cold. Ectopic activity in, for example, nerve-end neuroma, compressed nerves or nerve roots, dorsal root ganglia, and the thalamus may in different conditions underlie the spontaneous pain. Evoked pain may spread to neighboring areas, and the underlying pathophysiology involves peripheral and central sensitization. Maladaptive structural changes and a number of cell-cell interactions and molecular signaling underlie the sensitization of nociceptive pathways. These include alteration in ion channels, activation of immune cells, glial-derived mediators, and epigenetic regulation. The major classes of therapeutics include drugs acting on α₂δ subunits of calcium channels, sodium channels, and descending modulatory inhibitory pathways.

Association of quantitative sensory testing parameters with clinical outcome in patients with lumbar radiculopathy undergoing microdiscectomy

Background/Aim

This study aimed to establish the somatosensory profile of patients with lumbar radiculopathy at pre‐and post‐microdiscectomy and to explore any association between pre‐surgical quantitative sensory test (QST) parameters and post‐surgical clinical outcomes.

Methods

A standardized QST protocol was performed in 53 patients (mean age 38 ± 11 years, 26 females) with unilateral L5/S1 radiculopathy in the main pain area (MPA), affected dermatome and contralateral mirror sites and in age‐ and gender‐,and body site‐matched healthy controls. Repeat measures at 3 months included QST, the Oswestry Disability Index (ODI) and numerous other clinical measures; at 12 months, only clinical measures were repeated. A change <30% on the ODI was defined as ‘no clinically meaningful improvement’.

Results

Patients showed a significant loss of function in their symptomatic leg both in the dermatome (thermal, mechanical, vibration detection p < .002), and MPA (thermal, mechanical, vibration detection, mechanical pain threshold, mechanical pain sensitivity p < .041) and increased cold sensitivity in the MPA (p < .001). Pre‐surgical altered QST parameters improved significantly post‐surgery in the dermatome (p < .018) in the symptomatic leg and in the MPA (p < .010), except for thermal detection thresholds and cold sensitivity. Clinical outcomes improved at 3 and 12 months (p < .001). Seven patients demonstrated <30% change on the ODI at 12 months. Baseline loss of function in mechanical detection in the MPA was associated with <30% change on the ODI at 12 months (OR 2.63, 95% CI 1.09–6.37, p = .032).

Conclusion

Microdiscectomy resulted in improvements in affected somatosensory parameters and clinical outcomes. Pre‐surgical mechanical detection thresholds may be predictive of clinical outcome.

Significance

This study documented quantitative sensory testing (QST) profiles in patients with lumbar radiculopathy in their main pain area (MPA) and dermatome pre‐ and post‐microdiscectomy and explored associations between QST parameters and clinical outcome. Lumbar radiculopathy was associated with loss of function in modalities mediated by large and small sensory fibres. Microdiscectomy resulted in significant improvements in loss of function and clinical outcomes in 85% of our cohort. Pre‐surgical mechanical detection thresholds in the MPA may be predictive of clinical outcome.

Psychological factors can cause false pain classification on painDETECT

Background and aims The painDETECT questionnaire (PD-Q) has been widely used as a screening tool for the identification of neuropathic pain (NeP) as well as a tool for the characterization of patients' pain profile. In contrast to other NeP screening tools, the PD-Q is the only screening tool with weighted sensory descriptors. It is possible that responses to the PD-Q sensory descriptors are influenced by psychological factors, such as catastrophizing or anxiety, which potentially might contribute to an overall higher score of PD-Q and a false positive identification of NeP. This study aimed to explore (i) the relationship between psychological factors (catastrophizing, anxiety, depression and stress) and the total PD-Q score and (ii) if psychological factors are associated with false positive identifications of NeP on the PD-Q compared to clinically diagnosed NeP. Methods The study was a retrospective review of 1,101 patients attending an outpatient pain centre. Patients were asked to complete the PD-Q, the Pain Catastrophizing Scale (PCS), the Depression, Anxiety and Stress Scale (DASS) and the Brief Pain Inventory (BPI). For patients who were identified by PD-Q as having NeP, their medical records were reviewed to establish if they had a clinical diagnosis of NeP. Results Accounting for missing data, complete datasets of 652 patients (mean age 51 (SD14) years, range 18-88; 57% females) were available for analysis. Based on PD-Q scoring, NeP was likely present in 285 (44%) patients. Depression, anxiety, stress, catastrophizing, BPI pain and BPI interference were all significantly related to each other (p < 0.0001) and patients displaying these traits were significantly more likely to have a positive PD-Q score (p < 0.0001). For patients classified by PD-Q as having NeP, only 50% of patients had a clinical diagnosis of NeP. Anxiety was significantly associated with a false positive classification of NeP on PD-Q (p = 0.0036). Conclusions Our retrospective study showed that psychological factors including catastrophizing, depression, anxiety, and stress were all influential in producing a higher score on the PD-Q. We observed a high rate of false positive NeP classification which was associated with the presence of anxiety. Implications Clinicians and researchers should be aware that a patient's psychological state may influence the responses to PD-Q and consequently the final PD-Q score and its NeP classification.

Evaluation of the Neuropathic Component of Chronic Low Back Pain

OBJECTIVES

Assessment of neuropathic pain in chronic low back syndromes is important. However, there is currently no gold standard for its diagnosis. The aim of this observational cross-sectional study was to assess the neuropathic component of pain in various chronic low back pain syndromes using a range of diagnostic tests.

MATERIALS AND METHODS

Included in this study were 63 patients with chronic axial low back pain (ALBP), 48 patients with chronic radicular syndromes (CRS) comprising 23 with discogenic compression (CDRS) and 25 with lumbar spinal stenosis (LSS), and 74 controls. PainDETECT questionnaire (PDQ), quantitative sensory testing (QST), and skin biopsy with evaluation of intraepidermal nerve fiber density (IENFD) were used to assess the neuropathic pain component.

RESULTS

Positive PDQ (≥19) was obtained more frequently in patients with CDRS and LSS (26.1% and 12.0%, respectively) compared with patients with ALBP (1.6%, P<0.001). The proportion of patients with sensory loss confirmed by QST was lowest in the ALBP subgroup (23.8%) compared with CDRS (47.8%), and LSS (68.0%) subgroups (P<0.001). A reduction in IENFD was disclosed in a proportion of up to 52.0% of affected roots in patients with CRS.

DISCUSSION

Neuropathic pain is quite frequent in CRS, and QST reveals sensory loss as a frequent abnormality in patients with CRS. Using a cut-off value of 19, PDQ identified a neuropathic component in a relatively low proportion of patients with CRS. CRS may be associated with a reduction in IENFD.

Clinical indicators to identify neuropathic pain in low back-related leg pain: protocol for a modified Delphi study

INTRODUCTION

Neuropathic low back-related leg pain (LBLP) can be a challenge to healthcare providers to diagnose and treat. Accurate diagnosis of neuropathic pain is fundamental to ensure appropriate intervention is given. However, to date there is no gold standard to diagnose neuropathic LBLP. A Delphi study will therefore be conducted to obtain an expert-derived consensus list of clinical indicators to identify a neuropathic component to LBLP.

METHODS/ANALYSIS

Included participants will be considered experts within the field as measured against a predefined eligibility criterion. Through an iterative multistage process, participants will rate their agreement with a list of clinical indicators and suggest any missing clinical indicators during each round. Agreement will be measured using a 5-point Likert scale. Descriptive statistics will be used to measure agreement; median, IQR and percentage of agreement. A priori consensus criteria will be defined for each round. Data analysis at the end of round three will enable a list of clinical indicators to be derived.

ETHICS AND DISSEMINATION

Ethical approval was gained from the University of Birmingham (ERN_19-1142). On completion of the study, findings will be disseminated in a peer-reviewed journal and presented at relevant conferences.

Diagnostic utility of patient history, clinical examination and screening tool data to identify neuropathic pain in low back-related leg pain: protocol for a systematic review

INTRODUCTION

Neuropathic low back-related leg pain (LBLP) can be a challenge to healthcare providers to diagnose and treat. Accurate diagnosis of neuropathic pain is fundamental to ensure appropriate intervention is given. However, to date there is no gold standard to diagnose neuropathic LBLP. Patient examination guidelines and screening tools have been developed and validated for the purpose of diagnosing neuropathic pain in LBLP; however, there has been no systematic review conducted to compare the diagnostic validity of these methods. Therefore, this systematic review will investigate the diagnostic utility of patient history, clinical examination and screening tool data to identify neuropathic pain in LBLP.

METHODS AND ANALYSIS

This protocol is informed and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis-Protocols. CINAHL, EMBASE, MEDLINE, Web of Science, Cochrane Library, AMED, Pedro, PubMed, key journals and grey literature will be searched rigorously to find diagnostic accuracy studies investigating patient examination data to identify neuropathic pain in LBLP patients. Two independent reviewers will conduct the search, extract the data and assess risk of bias for included studies using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. The overall quality of included studies will be evaluated using Grading of Recommendations, Assessment, Development and Evaluation guidelines. A meta-analysis will be conducted if deemed appropriate. Otherwise, a narrative synthesis will be conducted.

ETHICS AND DISSEMINATION

No research ethics is required for this systematic review since patient data will not be collected. This review will help to inform healthcare professionals and researchers on the most effective means in which to diagnose neuropathic pain in LBLP. Results of this review will be submitted for publication in a peer-review journal and conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42019140861.

painPREDICT: first interim data from the development of a new patient-reported pain questionnaire to predict treatment response using sensory symptom profiles

Objective: Sensory symptom patterns may be useful for predicting treatment response, and, thus, improve individual therapy in patients suffering from neuropathic pain (NeP). Existing screening questionnaires focus predominately on neuropathic mechanisms without consideration of nociceptive mechanisms or mixed pain states. This study aimed to develop a new questionnaire, painPREDICT, using a wide set of patient-reported descriptors potentially associated with neuropathic and nociceptive pain mechanisms, and to explore sensory symptom patterns. Methods: PainPREDICT was constructed based on exploratory (n = 27 patients) and cognitive debriefing interviews (n = 49 patients and nine physicians), across five NeP conditions. The pilot questionnaire was then administered in a non-interventional, cross-sectional, multi-center study to 840 pain patients across the US and Germany. The identification of a sensory symptom pattern was based on hybrid clustering resulting from items standardization followed by principal component analysis. Results: The final questionnaire included 20 items covering: pain intensity, location of pain, course of pain, and sensory symptoms. Most patients participating in the cross-sectional study suffered either from painful diabetic polyneuropathy (n = 330) or radiculopathy (n = 349), fewer from central pain (n = 61) or other types of NeP (n = 100). The hybrid clustering of the new questionnaire data identified three different characteristic sensory symptom profiles in patients with NeP: "Irritable nociceptors", "deafferentation pain", and "pain attacks with nociceptive component". Although some differences in the distribution of the sensory profiles were found, all profiles were represented in all NeP etiology groups. Conclusions: This study set the ground of painPREDICT and showed promising results for its use to categorize patients according to sensory symptom patterns.

Pain and Depression: A Systematic Review

BACKGROUND

Pain comorbid with depression is frequently encountered in clinical settings and often leads to significant impaired functioning. Given the complexity of comorbidities, it is important to address both pain and depressive symptoms when evaluating treatment options.

AIM

To review studies addressing pain comorbid with depression, and to report the impact of current treatments.

METHOD

A systematic search of the literature databases was conducted according to predefined criteria. Two authors independently conducted a focused analysis of the full-text articles and reached a consensus on 28 articles to be included in this review.

RESULTS

Overall, studies suggested that pain and depression are highly intertwined and may co-exacerbate physical and psychological symptoms. These symptoms could lead to poor physical functional outcomes and longer duration of symptoms. An important biochemical basis for pain and depression focuses on serotonergic and norepinephrine systems, which is evident in the pain-ameliorating properties of serotonergic and norepinephrine antidepressants. Alternative pharmacotherapies such as ketamine and cannabinoids appear to be safe and effective options for improving depressive symptoms and ameliorating pain. In addition, cognitive-behavioral therapy may be a promising tool in the management of chronic pain and depression.

CONCLUSION

The majority of the literature indicates that patients with pain and depression experience reduced physical, mental, and social functioning as opposed to patients with only depression or only pain. In addition, ketamine, psychotropic, and cognitive-behavioral therapies present promising options for treating both pain and depression.

Aging of mouse intervertebral disc and association with back pain

With the increased burden of low back pain (LBP) in our globally aging population there is a need to develop preclinical models of LBP that capture clinically relevant features of physiological aging, degeneration, and disability. Here we assess the validity of using a mouse model system for age-related LBP by characterizing aging mice for features of intervertebral disc (IVD) degeneration, molecular markers of peripheral sensitization, and behavioral signs of pain. Compared to three-month-old and one-year-old mice, two-year-old mice show features typical of IVD degeneration including loss of disc height, bulging, innervation and vascularization in the caudal lumbar IVDs. Aging is also associated with the loss of whole-body bone mineral density in both male and female mice, but not associated with percent lean mass or body fat. Additionally, two-year-old mice have an accumulation of TRPA1 channels and sodium channels NaV1.8 and NaV1.9 in the L4 and L5 lumbar dorsal root ganglia consistent with changes in nociceptive signaling. Lastly, the effect of age, sex, and weight on mobility, axial stretching and radiating pain measures was assessed in male and female mice ranging from two months to two years in a general linear model. The model revealed that regardless of sex or weight, increased age was a predictor of greater reluctance to perform axial stretching and sensitivity to cold, but not heat in mice.

Sensory profiles are comparable in patients with distal and proximal entrapment neuropathies, while the pain experience differs

OBJECTIVE

Distal and proximal entrapment neuropathies such as carpal tunnel syndrome (CTS) and cervical radiculopathy (CR) share similar etiologies. Experimental models suggest that, despite comparable etiology, pathomechanisms associated with injuries of the peripheral and central axon branches are distinct. This study therefore compared self-reported and elicited sensory profiles in patients with distal and proximal entrapment neuropathies.

METHODS

Patients with electrodiagnostically confirmed CTS (n = 103) and patients with CR (n = 23) were included in this study. A group of healthy participants served as controls (n = 39). Symptoms and sensory profiles were evaluated using quantitative sensory testing (QST) and a self-reported neuropathic pain questionnaire (painDETECT).

RESULTS

Both patient groups were characterized by a loss of function in thermal and mechanical detection in the main pain area and dermatome compared to healthy reference data (p < .001). There was no significant difference between patients with CTS and CR in pain and detection thresholds except for reduced vibration sense in the main pain area (p < .001) and reduced pressure pain sensitivity in the dermatome in patients with CR (p < .001). However, patients with CR reported higher pain intensities (p = .008), more severe pain attacks (p = .009) and evoked pain by light pressure (p = .002) compared to patients with CTS.

CONCLUSION

While QST profiles were similar between patients with CTS and CR, self-reported pain profiles differed and may suggest distinct underlying mechanisms in these patient cohorts.

Sensory Symptom Profiles of Patients With Neuropathic Pain After Spinal Cord Injury

AIM

Individuals experiencing neuropathic pain (NP) after spinal cord injury (SCI) present with a variety of pain descriptors in different combinations and at different intensities. These sensory features form distinct patterns, known as sensory symptom profiles.

METHODS

In the present cross-sectional study, we have used a multivariate statistical method (multiple correspondence analysis) to categorize the sensory symptom profiles of a cohort of 338 patients with at-level or below-level NP after SCI. We also investigated possible associations between positive neuropathic symptoms and features of the neurological lesion.

RESULTS

The majority of participants had a combination of pain descriptors, with 59% presenting with 3 or 4 pain subtypes. No significant associations were found between specific pain profiles and etiology or clinical degree of the neurological lesion. Furthermore, similar symptom profiles were seen in patients with at-level and below-level NP. The most frequent pattern observed in patients with cervical SCI consisted predominantly of electric shocks and tingling, without burning, pressure pain, or allodynia.

CONCLUSIONS

Classification of SCI-NP patients into the 5 groups identified in the present study based on their distinct sensory symptom profiles may allow identification of those most likely to respond to a specific analgesic approach.

Neuropathic Pain in Low Back-Related Leg Pain Patients: What Is the Evidence of Prevalence, Characteristics, and Prognosis in Primary Care? A Systematic Review of the Literature

This systematic review synthesizes literature describing prevalence, characteristics, and prognosis of low back-related leg pain (LBLP) patients with neuropathic pain in primary care and/or similar settings. Inclusion and exclusion criteria were developed and used by independent reviewers to screen citations for eligibility. The initial search yielded 24,948 citations; after screening 12 studies were included. Neuropathic pain was identified using case ascertainment tools (n = 5), clinical history with examination (n = 4), and using LBLP samples assumed neuropathic (n = 3). Neuropathic pain prevalence varied from 19% to 80%. There was consistent evidence for higher back-related disability (n = 3), poorer health-related quality of life (n = 2), and some evidence for more severe depression (n = 2), anxiety (n = 3), and pain intensity (n = 4) in patients with neuropathic pain. Results were less consistent when cases were identified through clinical history with examination than those identified using case ascertainment tools. Prognosis (n = 1) of LBLP patients with neuropathic pain was worse compared with those without, in all outcomes (leg pain intensity, leg and back-related disability, self-reported general health) except back pain intensity. No studies described prognostic factors. This systematic review highlights the evidence gap in neuropathic pain in LBLP in primary care, especially with respect to prognosis.

PERSPECTIVE

Patients with LBLP may have neuropathic pain. This systematic review emphasizes the paucity of evidence describing the characteristics and prognosis of neuropathic pain in this patient population. Future research investigating prognosis of these patients with neuropathic pain is likely to contribute to better understanding and management.

Treatment of painful radiculopathies with capsaicin 8% cutaneous patch

BACKGROUND AND OBJECTIVE

The treatment of neuropathic pain due to low-back (lumbosacral) radiculopathies, a common source of neuropathic pain, is challenging and often requires a multimodal therapeutic approach. The capsaicin 8% patch is the first topical analgesic licensed for peripheral neuropathic pain. To evaluate this treatment, a subset of patients with painful radiculopathy (lumbar and cervical, including ventral and dorsal rami) enrolled into the multicenter, non-interventional QUEPP study (Qutenza ² - safety and effectiveness in peripheral neuropathic pain) was analyzed.

METHODS

Of the 1044 study participants, 50 were diagnosed with painful radiculopathy as only peripheral neuropathic pain syndrome and were eligible for evaluation. Patients received a single treatment (visit 1) with follow-up visits 2-5 at weeks 1-2, 4, 8 and 12. Parameters assessed at all visits included pain intensity, neuropathy symptoms and side effects. Quality of life (SF-12) and painDETECT ¹ questionnaires were completed at baseline and final visit. Data was analyzed by patch application site and duration of pain.

RESULTS

Topical treatment led to a significant decrease of pain intensity between weeks 1/2 and week 12 versus baseline at the application sites representing dermatomes of ventral (N = 26) and dorsal rami (N = 13) of spinal nerves. A significant decline (p ≤ .001) of numeric pain rating scale scores was observed between weeks 1/2 following patch application and the end of observation (week 12) in the overall radiculopathy group (N = 50), and the groups with either 3 months to 2 years (N = 14) or >2 years (N = 23) duration of pain. Pain relief of at least 30% was observed in 50.0%, 71.4% and 39.1% of patients in the respective groups. Four patients experienced in total seven adverse drug reactions (application site pain or pruritus).

CONCLUSION

Effective neuropathic pain relief was observed after patch application within the innervation territories of both dorsal and ventral branches of the spinal nerve. Further controlled randomized trials are indicated.

Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations

There is tremendous interpatient variability in the response to analgesic therapy (even for efficacious treatments), which can be the source of great frustration in clinical practice. This has led to calls for "precision medicine" or personalized pain therapeutics (ie, empirically based algorithms that determine the optimal treatments, or treatment combinations, for individual patients) that would presumably improve both the clinical care of patients with pain and the success rates for putative analgesic drugs in phase 2 and 3 clinical trials. However, before implementing this approach, the characteristics of individual patients or subgroups of patients that increase or decrease the response to a specific treatment need to be identified. The challenge is to identify the measurable phenotypic characteristics of patients that are most predictive of individual variation in analgesic treatment outcomes, and the measurement tools that are best suited to evaluate these characteristics. In this article, we present evidence on the most promising of these phenotypic characteristics for use in future research, including psychosocial factors, symptom characteristics, sleep patterns, responses to noxious stimulation, endogenous pain-modulatory processes, and response to pharmacologic challenge. We provide evidence-based recommendations for core phenotyping domains and recommend measures of each domain.

Regenerative peripheral neuropathic pain: novel pathological pain, new therapeutic dimension

After peripheral nerve damage, injured or stressed primary sensory neurons (PSNs) transmitting pathological pain (pathopain) sensitize central nervous system (CNS) neural circuits and determine behavioral phenotypes of peripheral neuropathic pain (PNP). Therefore, phenotypic profiling of pathopain-transmitting PSNs is vital for probing and discovering PNP conditions. Following peripheral nerve injuries (PNIs), PNP might be potentially transmitted by distinct classes of damaged or stressed PSNs, such as axotomized PSNs without regeneration (axotomy-non-regenerative neurons), axotomized PSNs with accurate regeneration (axotomy-regenerative neurons), and spared intact PSNs adjacent to axotomized neurons (axotomy-spared neurons). Both axotomy-non-regenerative neurons and axotomy-spared neurons have been definitely shown to participate in specific PNP transmission. However, whether axotomy-regenerative neurons could transmit PNP with unique features has remained unclear. Recent studies in rodent models of axonotmesis have clearly demonstrated that axotomy-regenerative neurons alone transmit persistent pathological pain with unique behavioral phenotypes. In this review, we exclusively review this novel category of PNP, reasonably term it ‘regenerative peripheral neuropathic pain’, and finally discuss its potential clinical significance as a new therapeutic dimension for PNIs beyond nerve regeneration.

First report of important causal relationship between the Adamkiewicz artery vasospasm and dorsal root ganglion cell degeneration in spinal subarachnoid hemorrhage: An experimental study using a rabbit model

Background:

The blood supply of the lower spinal cord is heavily dependent on the artery of Adamkiewicz. The goal of this study was to elucidate the effects of lumbar subarachnoid hemorrhage (SAH) on the lumbar 4 dorsal root ganglion (L4DRG) cells secondary to Adamkiewicz artery (AKA) vasospasm.

Materials and Methods:

This study was conducted on 20 rabbits, which were randomly divided into three groups: Spinal SAH (n = 8), serum saline (SS) (SS; n = 6) and control (n = 6) groups. Experimental spinal SAH was performed. After 20 days, volume values of AKA and neuron density of L4DRG were analyzed.

Results:

The mean alive neuron density of the L4DRG was 15420 ± 1240/mm³ and degenerated neuron density was 1045 ± 260/mm³ in the control group. Whereas, the density of living and degenerated neurons density were 12930 ± 1060/mm³ and 1365 ± 480/mm³ in serum saline (SS), 9845 ± 1028/mm³ and 4560 ± 1340/mm³ in the SAH group. The mean volume of imaginary AKAs was estimated as 1,250 ± 0,310 mm³ in the control group and 1,030 ± 0,240 mm³ in the SF group and 0,910 ± 0,170 mm³ in SAH group. Volume reduction of the AKAs and neuron density L4DRG were significantly different between the SAH and other two groups (P < 0.05).

Conclusion:

Decreased volume of the lumen of the artery of Adamkiewicz was observed in animals with SAH compared with controls. Increased degeneration the L4 dorsal root ganglion in animals with SAH was also noted. Our findings will aid in the planning of future experimental studies and determining the clinical relevance on such studies.

Characterizing neuropathic pain profiles: enriching interpretation of painDETECT

Purpose

To psychometrically evaluate painDETECT, a patient-reported screening questionnaire for neuropathic pain (NeP), for discriminating among sensory pain symptoms (burning, tingling/prickling, light touching, sudden pain attacks/electric shock-type pain, cold/heat, numbness, and slight pressure).

Methods

The seven-item version of painDETECT provides an overall score that targets only sensory symptoms, while the nine-item version adds responses on two items to the overall score, covering pain course pattern and pain radiation. Both versions have relevance in terms of characterizing broad NeP. The nine- and seven-item versions of painDETECT were administered to subjects with confirmed NeP across six conditions identified during office visits to US community-based physicians. Responses on the sensory symptom items were dichotomized into “at least moderate” (ie, moderate, strongly, very strongly) relative to the combined other responses (never, hardly noticed, slightly). Logistic regression of dichotomized variables on the total painDETECT score provided probabilities of experiencing each symptom across the range of painDETECT scores.

Results

Both painDETECT versions discriminated among the symptoms with similar probabilities across the score ranges. Using these data, the probability of moderately experiencing each pain sensory item was estimated for a particular score, providing a pain profile. Additionally, the likelihood of experiencing each sensation was determined for a discrete increase in score, ie, the odds of at least a moderate sensation of burning (versus less than a moderate sensation) was 1.29 for a 1-point increase, 3.52 for a 5-point increase, and 12.42 for every 10-point increase in the nine-item painDETECT score.

Conclusion

painDETECT differentiates pain profiles across the range of scores such that, for a particular score, the probability of experiencing at least a moderate sensation of each symptom was determined and compared. These results can help characterize NeP symptomatology, enrich interpretation of painDETECT scores, and provide a basis for individualizing NeP management.

The painDETECT project - far more than a screening tool on neuropathic pain

Background and objectives The painDETECT questionnaire (PD-Q), a simple and reliable screening questionnaire of neuropathic pain, was developed in 2004 in cooperation with the German Research Network on Neuropathic Pain. The initial aim was to implement quality management and to improve the situation of neuropathic pain (NeP) patients in Germany. The PD-Q proved immediately successful and was translated into and validated in multiple languages. Subsequently a comprehensive electronic system (PD) comprising various validated questionnaires with regard to pain typical comorbidities, such as function, sleep, mood or anxiety, was implemented Germany wide. We aimed to provide a comprehensive overview about the development and validation as well as the application of the PD-Q in various clinical conditions. Methods This overview is based on a literature search on English full-text papers using the term 'painDETECT' in Medline and PubMed covering the time period from 2006 to September 2015, amended with further publications cited in the retrieved publications or provided by the questionnaire developers. Results PD-Q as screening tool for NeP described in patients with lower back pain (8 studies), rheumatoid arthritis and osteoarthritis (10), thoracotomy (2 studies), tumor diseases (4 studies), fibromyalgia (4 studies), diverse musculoskeletal conditions (12 studies) and diverse other conditions (10 studies). In addition, the PD-Q was used in 9 studies that investigated the effect of drugs for the treatment of patients with a NeP component. Conclusion To date more than 300,000 patients were assessed, providing the basis for one of the world's largest datasets for chronic pain. Among others the extensive pool of PD-Q data triggered the idea of subgrouping patients on the basis of their individual sensory profiles which might in the future lead to a stratified treatment approach and ultimately to personalized therapy. Started as a healthcare utilization project in Germany, the PD-Q is nowadays used for clinical and research purposes around the world.

Pain Assessment--Can it be Done with a Computerised System? A Systematic Review and Meta-Analysis

Background: Mobile and web technologies are becoming increasingly used to support the treatment of chronic pain conditions. However, the subjectivity of pain perception makes its management and evaluation very difficult. Pain treatment requires a multi-dimensional approach (e.g., sensory, affective, cognitive) whence the evidence of technology effects across dimensions is lacking. This study aims to describe computerised monitoring systems and to suggest a methodology, based on statistical analysis, to evaluate their effects on pain assessment. Methods: We conducted a review of the English-language literature about computerised systems related to chronic pain complaints that included data collected via mobile devices or Internet, published since 2000 in three relevant bibliographical databases such as BioMed Central, PubMed Central and ScienceDirect. The extracted data include: objective and duration of the study, age and condition of the participants, and type of collected information (e.g., questionnaires, scales). Results: Sixty-two studies were included, encompassing 13,338 participants. A total of 50 (81%) studies related to mobile systems, and 12 (19%) related to web-based systems. Technology and pen-and-paper approaches presented equivalent outcomes related with pain intensity. Conclusions: The adoption of technology was revealed as accurate and feasible as pen-and-paper methods. The proposed assessment model based on data fusion combined with a qualitative assessment method was revealed to be suitable. Data integration raises several concerns and challenges to the design, development and application of monitoring systems applied to pain.

Scratching the surface: the processing of pain from deep tissues

Although most pain research focuses on skin, muscles, joints and viscerae are major sources of pain. We discuss the mechanisms of deep pains arising from somatic and visceral structures and how this can lead to widespread manifestations and chronification. We include how both altered peripheral and central sensory neurotransmission lead to deep pain states and comment on key areas such as top-down modulation where little is known. It is vital that the clinical characterization of deep pain in patients is improved to allow for back translation to preclinical models so that the missing links can be ascertained. The contribution of deeper somatic and visceral tissues to various chronic pain syndromes is common but there is much we need to know.

Neuropathic low back pain in clinical practice

Background and objective

Low back pain (LBP) is one of the most common chronic pain conditions. This paper reviews the available literature on the role of neuropathic mechanisms in chronic LBP and discusses implications for its clinical management, with a particular focus on pharmacological treatments.

Databases and data treatment

Literature searches were performed in PubMed, key pain congresses and ProQuest Dialog to identify published evidence on neuropathic back pain and its management. All titles were assessed for relevant literature.

Results

Chronic LBP comprises both nociceptive and neuropathic components, however, the neuropathic component appears under‐recognized and undertreated. Neuropathic pain (NP) is challenging to manage. Many patients with chronic LBP have pain that is refractory to existing treatments. Typically, less than half of patients experience clinically meaningful analgesia with oral pharmacotherapies; these are also associated with risks of adverse effects. Paracetamol and NSAIDs, although widely used for LBP, are unlikely to ameliorate the neuropathic component and data on the use of NP medications such as antidepressants and gabapentin/pregabalin are limited. While there is an unmet need for improved treatment options, recent data have shown tapentadol to have efficacy in the neuropathic component of LBP, and studies suggest that the capsaicin 8% patch and lidocaine 5% medicated plaster, topical analgesics available for the treatment of peripheral NP, may be a valuable additional approach for the management of neuropathic LBP.

Conclusions

Chronic LBP often has an under‐recognized neuropathic component, which can be challenging to manage, and requires improved understanding and better diagnosis and treatment.

What does this review add?

Increased recognition and improved understanding of the neuropathic component of low back pain raises the potential for the development of mechanism‐based therapies.

Open and retrospective studies suggest that agents like tapentadol and topical analgesics — such as the capsaicin 8% patch and the lidocaine 5% medicated plaster — may be effective options for the treatment of neuropathic low back pain in defined patient groups.

Characteristics of patients with low back and leg pain seeking treatment in primary care: baseline results from the ATLAS cohort study

Background

Patients with back pain radiating to the leg(s) report worse symptoms and poorer recovery than those with back pain alone. Robust evidence regarding their epidemiological profile is lacking from primary care, the setting where most of these patients will present and be managed. Our objective was to describe the characteristics of patients with back and leg pain, including sciatica, seeking treatment in primary care.

Methods

Adults visiting their general practitioner with back and leg pain, of any duration and severity, were invited to participate. Participants completed questionnaires, underwent clinical assessments and received MRI scans. Characteristics of the sample are described, and differences between patients diagnosed with referred leg pain and those with sciatica are analysed.

Results

Six hundred nine patients participated; 62.6 % were female, mean (SD) age 50.2 (13.9). 67.5 % reported pain below the knee, 60.7 % were in paid employment with 39.7 % reporting time off work. Mean disability (RMDQ) was 12.7 (5.7) and mean pain intensity was 5.6 (2.2) and 5.2 (2.4) for back and leg respectively. Mean sciatica bothersomeness index (SBI) was 14.9 (5.1). Three quarters (74.2 %) were clinically diagnosed as having sciatica. In the sciatica group, leg pain intensity, neuropathic pain, pain below the knee, leg pain worse than back pain, SBI and positive MRI findings were significantly higher as compared to patients with referred leg pain.

Conclusions

This primary care cohort reported high levels of disability and pain. This is the first epidemiological study of unselected primary care patients seeking healthcare for back and leg pain. Follow-up of this cohort will investigate the prognostic value of their baseline characteristics. This new information will contribute to our understanding of the characteristics and clinical features of this population, and will underpin future research aimed at defining prognostic subgroups to enable better targeting of health care provision.

Neuropathic Pain Components in Patients with Lumbar Spinal Stenosis

PURPOSE

To determine the prevalence and characteristics of neuropathic pain (NP) in patients with lumbar spinal stenosis (LSS) according to subgroup analysis of symptoms.

MATERIALS AND METHODS

We prospectively enrolled subjects with LSS (n=86) who were scheduled to undergo spinal surgery. The patients were divided into two groups according to a chief complaint of radicular pain or neurogenic claudication. We measured patient's pain score using the visual analog scale (VAS), Oswestry Disability Index (ODI) and Leads Assessment of Neuropathic Symptoms and Signs (LANSS). According to LANSS value, the prevalence of NP component pain in patients with LSS was assessed. Statistical analysis was performed to find the relationship between LANSS scores and the other scores.

RESULTS

From our sample of 86 patients, 31 (36.0%) had a NP component, with 24 (63.4%) in the radicular pain group having NP. However, only seven patients (15.6%) in the neurogenic claudication group had NP. The LANSS pain score was not significantly correlated with VAS scores for back pain, but did correlate with VAS scores for leg pain (R=0.73, p<0.001) and with ODI back pain scores (R=0.54, p<0.01).

CONCLUSION

One-third of the patients with LSS had a NP component. The presence of radicular pain correlated strongly with NP. The severity of leg pain and ODI score were also closely related to a NP component. This data may prove useful to understanding the pain characteristics of LSS and in better designing clinical trials for NP treatment in patients with LSS.