The reliability of clinical judgments and criteria associated with mechanisms-based classifications of pain in patients with low back pain disorders: a preliminary reliability study

Signs of Nervous System Sensitization in Female Runners with Chronic Patellofemoral Pain

Background

Patellofemoral pain (PFP) is a common overuse injury among runners, affecting females at a higher rate than males. PFP can often become chronic, with evidence suggesting it may be linked to both peripheral and central sensitization of the nervous system. Sensitization of the nervous system can be identified through quantitative sensory testing (QST).

Hypothesis/Purpose

The primary objective of this pilot study was to quantify and compare pain sensitivity as identified through QST measures, in active female runners with and without PFP.

Study Design

Cohort Study.

Methods

Twenty healthy female runners and 17 female runners with chronic PFP symptoms were enrolled. Subjects completed the Knee injury and Osteoarthritis Outcome Score for Patellofemoral Pain (KOOS-PF), University of Wisconsin Running Injury and Recovery Index (UWRI), and the Brief Pain Inventory (BPI). QST consisted of pressure pain threshold testing to three local and three distant sites to the knee, heat temporal summation, heat pain threshold, and conditioned pain modulation. Data was analyzed utilizing independent t-tests for comparison of between-group data, effect sizes for QST measures (Pearson's r), and Pearson's correlation coefficient between pressure pain threshold values at the knee and functional testing.

Results

The PFP group exhibited significantly lower scores on the KOOS-PF (p<0.001), BPI Pain Severity and Interference Scores (p<0.001), and UWRI (p<0.001). Primary hyperalgesia, identified through decreased pressure pain threshold at the knee, was detected in the PFP group at the central patella (p<0.001), lateral patellar retinaculum (p=0.003), and patellar tendon (p=0.006). Secondary hyperalgesia, a sign of central sensitization, was observed via differences in pressure pain threshold testing for the PFP group at the uninvolved knee (p=0.012 to p=0.042), involved extremity remote sites (p=0.001 to p=0.006), and uninvolved extremity remote sites (p=0.013 to p=0.021).

Conclusion

Compared to healthy controls, female runners with chronic PFP symptoms exhibit signs of both peripheral sensitization. Despite actively participating in running, nervous system sensitization may contribute to continued pain in these individuals. For female runners with chronic PFP, physical therapy management may need to include interventions which address signs of central and peripheral sensitization.

Level of Evidence

Level 3.

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.

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.

Diagnostic accuracy of the clinical indicators to identify central sensitization pain in patients with musculoskeletal pain

Background

The identification of central sensitization (CS) is an important aspect in the management of patients with chronic musculoskeletal pain. Several methods have been developed, including clinical indicators and psychophysical measures. However, whether clinical indicators coincide with the psychophysical test of CS-related sign and symptoms is still unknown. Therefore, the present study aimed to analyze the diagnostic accuracy of the clinical indicators in identifying CS-related sign and symptoms in patients with musculoskeletal pain.

Methods

One-hundred consecutive patients with musculoskeletal pain were included. Clinical indicators (index method) based on a combination of patient self-report pain characteristics and physical examination were used to identify the phenotype of patients with musculoskeletal pain and the predominance of the CS-related sign and symptoms. Conditioned pain modulation (CPM) was assessed by the Cold Pressor Test (reference standard), which is a psychophysical test used to detect impairment of CPM. Measurements of the diagnostic accuracy were performed.

Results

Twenty-seven patients presented predominance of CS-related sign and symptoms in the assessment of the clinical indicators, and 20 had impairment of CPM. Clinical indicators showed high accuracy (75.0%; 95% confidence interval = 65.3 to 83.1), high specificity (80.0%; 95% confidence interval = 69.6 to 88.1), high negative predictive value (87.7%; 95% confidence interval = 81.2 to 92.1), and a relevant positive likelihood ratio (2.8, 95% confidence interval = 1.5 to 5.0) when compared to the Cold Pressor Test.

Conclusion

Clinical indicators demonstrated a valuable tool for detecting the impaired CPM, which is a remarkable feature of the CS-related sign and symptoms. Clinicians are encouraged to use the clinical indicators in the management of patients with musculoskeletal pain.

Quantitative Sensory Testing Discriminates Central Sensitization Inventory Scores in Participants with Chronic Musculoskeletal Pain: An Exploratory Study

BACKGROUND

The Central Sensitization Inventory (CSI) is often used in clinical settings to screen for the presence of central sensitization. However, various cutoff scores have been reported for this tool, and scores have not been consistently associated with widespread pain sensitivity as measured with quantitative sensory testing (QST). The purpose of this study was to compare QST profiles among asymptomatic controls and participants with chronic musculoskeletal pain (CMP), and to determine the association between self-report questionnaires and QST in participants with CMP.

METHODS

Twenty asymptomatic controls and 46 participants with CMP completed the CSI, PROMIS-29, and QST assessments of mechanical and thermal pain thresholds remote to the area of pain. Receiver Operating Characteristic analysis revealed a cutoff score of 33.5 for the CSI. PROMIS-29 Quality of Life (QOL) inventory and QST measures were compared between low and high CSI groups.

RESULTS

The high CSI group (n = 19) had significantly lower mechanical and thermal pain thresholds, and larger impairments in QOL measures, compared to the low CSI group (n = 27) and asymptomatic controls. Participants with CSI scores < 33.5 presented similarly to asymptomatic controls. Anxiety, pain interference, and CSI scores demonstrated the highest number of significant associations to QST measures.

CONCLUSION

A cutoff score of 33.5 on the CSI may be useful for discriminating widespread pain sensitivity and quality of life impairments in participants with CMP. Future studies should consider how the presence of high or low CSI may impact differential diagnosis, prognosis, and treatment responsiveness for patients with primary or secondary CMP.

Reliability of two functional clinical tests to evaluate trunk and lumbopelvic neuromuscular control and proprioception in a healthy population

OBJECTIVES

The need to accurately assess trunk and lumbopelvic proprioception and neuromuscular control is widely accepted. However, based on current literature, there is a lack of reliable clinical tests to evaluate these aspects in clinical practice. The objective of this study is to investigate intra- and inter-tester reliability of the lateral step down test and the lumbopelvic position-reposition test in a healthy population.

METHODS

Protocol and scoring methods were developed for the lateral step down test and lumbopelvic position-reposition test, used to assess trunk and lumbopelvic neuromuscular control and proprioception respectively. Each test was performed once by thirty participants and video analysis for test scoring was performed. Three items on the lateral step down test were scored to evaluate neuromuscular control and, four items on the lumbopelvic position-reposition test were scored to evaluate proprioception. Aggregate scores for each test were calculated based on the separate item scores. Intraclass correlation coefficients and linear weighted kappa coefficients were determined for intra- and inter-tester reliability.

RESULTS

Based on the aggregate score, excellent intra- and inter-tester reliability (ICC (2,1)=0.73-0.88) was found for both tests. Moderate/almost perfect intra-and inter-tester agreement (K=0.62-0.91) was found for the separate items of the lateral step down test and fair/substantial agreement (K=0.25-0.76) for the items of the lumbopelvic position-reposition test.

CONCLUSION

Current testing protocol and scoring method for the lateral step down test is reliable. Adjustments for the scoring method of the lumbopelvic position-reposition test are warranted to improve reliability.

The interrater reliability of a pain mechanisms-based classification for patients with nonspecific neck pain

OBJECTIVE

To examine the interrater reliability and agreement of a pain mechanisms-based classification for patients with nonspecific neck pain (NSNP).

METHODS

Design - Observational, cross-sectional reliability study with a simultaneous examiner design.

SETTING

University hospital-based outpatient physical therapy clinic.

PARTICIPANTS

A random sample of 48 patients, aged between 18 and 75 years old, with a primary complaint of neck pain was included.

INTERVENTIONS

Subjects underwent a standardized subjective and clinical examination, performed by 1 experienced physical therapist. Two assessors independently classified the participants' NSNP on 3 main outcome measures.

MAIN OUTCOME MEASURES

The Cohen kappa, percent agreement, and 95% confidence intervals (CIs) were calculated to determine the interrater reliability for (1) the predominant pain mechanism; (2) the predominant pain pattern; and (3) the predominant dysfunction pattern (DP).

RESULTS

There was almost perfect agreement between the 2 physical therapists' judgements on the predominant pain mechanism, kappa=.84 (95% CI, .65-1.00), p<.001. There was substantial agreement between the raters' judgements on the predominant pain pattern and predominant DP with respectively kappa=.61 (95% CI, .42-.80); and kappa=.62 (95% CI, .44-.79), p<.001.

CONCLUSION(S)

The proposed classification exhibits substantial to almost perfect interrater reliability. Further validity testing in larger neck pain populations is required before the information is used in clinical settings.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03147508 (https://clinicaltrials.gov/ct2/show/NCT03147508).

Clinical classification criteria for nonspecific low back pain: A Delphi-survey of clinical experts

BACKGROUND

Nonspecific low back pain (NSLBP) is a common problem. Attempts have been made to classify NSLBP patients into homogenous subgroups. Classification systems based on identifying the underlying mechanism(s) driving the disorder are clinically useful to guide specific interventions.

OBJECTIVE

To establish consensus among experts regarding clinical criteria suggestive of a dominance of 'articular', 'myofascial', 'neural', 'central', and 'sensorimotor control' dysfunction patterns (DPs) in NSLBP patients.

STUDY DESIGN

A 2-phase sequential design of a focus group and Delphi-study.

METHODS

A focus group with 10 academic experts was organized to elaborate on the different DPs discernible in LBP patients. Consecutively, a 3-round online Delphi-survey was designed to obtain consensual symptoms and physical examination findings for the 5 DPs resulting from the focus group.

RESULTS

Fifteen musculoskeletal physical therapists from Belgium and the Netherlands experienced in assessing and treating LBP patients completed the Delphi-survey. Respectively, 34 (response rate, 100.0%), 20 (58.8%) and 15 (44.12%) respondents replied to rounds 1, 2 and 3. Twenty-two 'articular', 20 'myofascial', 21 'neural', 18 'central' and 11 'sensorimotor control' criteria reached a predefined ≥80% consensus level. For example, after round 2, 85.0% of the Delphi-experts agreed to identify 'referred pain below the knee' as a subjective examination criterion suggestive for a predominant 'neural DP'.

CONCLUSION

These indicators suggestive of a clinical dominance of the proposed DPs could help clinicians to assess and diagnose NSLBP patients. Future reliability and validity testing is needed to determine how these criteria may help to improve physical therapy outcome for NSLBP patients.

Pain experiences of patients with musculoskeletal pain + central sensitization: A comparative Group Delphi Study

Objectives

Central sensitization (CS) is regarded as an important contributing factor for chronification of musculoskeletal pain (MSP). It is crucial to identify CS, as targeted multimodal treatment may be indicated. The primary objective of this study was therefore to explore pain experience of individuals with MSP+CS in order to gain a better understanding of symptoms in relation to CS from a patient perspective. The secondary objective was to investigate whether pain experiences of patients with MSP+CS differ from those of individuals with neuropathic pain (NP).

Methods

We conducted a comparative Group Delphi Study including patients with MSP+CS and neuropathic pain (NP). 13 guiding questions were used to gather information about sensory discriminatory, affective and associated bodily, mental and emotional phenomena related to the pain experience of patients. Descriptions were categorized using qualitative content analysis. Additionally, patients completed several pain related questionnaires.

Results

Nine participants with MSP+CS and nine participants with NP participated. The Delphi procedure revealed three main themes: psycho-emotional factors, bodily factors and environmental factors. Descriptions of patients with MSP+CS showed a complex picture, psycho-emotional factors seem to have a considerable impact on pain provocation, aggravation and relief. Impairments associated with mental ability and psyche affected many aspects of daily life. In contrast, descriptions of patients with NP revealed a rather mechanistic and bodily oriented pain experience.

Discussion

Patients with MSP+CS reported distinct features in relation to their pain that were not captured with current questionnaires. Insight in patient’s pain experience may help to choose and develop appropriate diagnostic instruments.

Clinical classification in low back pain: best-evidence diagnostic rules based on systematic reviews

Background

Clinical examination findings are used in primary care to give an initial diagnosis to patients with low back pain and related leg symptoms. The purpose of this study was to develop best evidence Clinical Diagnostic Rules (CDR] for the identification of the most common patho-anatomical disorders in the lumbar spine; i.e. intervertebral discs, sacroiliac joints, facet joints, bone, muscles, nerve roots, muscles, peripheral nerve tissue, and central nervous system sensitization.

Methods

A sensitive electronic search strategy using MEDLINE, EMBASE and CINAHL databases was combined with hand searching and citation tracking to identify eligible studies. Criteria for inclusion were: persons with low back pain with or without related leg symptoms, history or physical examination findings suitable for use in primary care, comparison with acceptable reference standards, and statistical reporting permitting calculation of diagnostic value. Quality assessments were made independently by two reviewers using the Quality Assessment of Diagnostic Accuracy Studies tool. Clinical examination findings that were investigated by at least two studies were included and results that met our predefined threshold of positive likelihood ratio ≥ 2 or negative likelihood ratio ≤ 0.5 were considered for the CDR.

Results

Sixty-four studies satisfied our eligible criteria. We were able to construct promising CDRs for symptomatic intervertebral disc, sacroiliac joint, spondylolisthesis, disc herniation with nerve root involvement, and spinal stenosis. Single clinical test appear not to be as useful as clusters of tests that are more closely in line with clinical decision making.

Conclusions

This is the first comprehensive systematic review of diagnostic accuracy studies that evaluate clinical examination findings for their ability to identify the most common patho-anatomical disorders in the lumbar spine. In some diagnostic categories we have sufficient evidence to recommend a CDR. In others, we have only preliminary evidence that needs testing in future studies. Most findings were tested in secondary or tertiary care. Thus, the accuracy of the findings in a primary care setting has yet to be confirmed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1549-6) contains supplementary material, which is available to authorized users.

Validation of a pain mechanism classification system (PMCS) in physical therapy practice

The objective of this study was to validate the clinical application of a pain mechanism classification system (PMCS) in clinical practice. We analyzed data abstracted from the medical records of patients who were treated in the outpatient clinics of a large urban rehabilitation hospital in Chicago. We hypothesized that there would be good agreement between the PMCS determined by trained therapists and the PMCS category assigned based on a computer-generated statistical model using patients' signs and symptoms. Using cluster analysis, when we assumed five groups, 97% of patients could be classified. Sensitivity and specificity results with 95% confidence intervals were calculated for the categories using the physical therapist assigned categories (PMCS) as the criterion standard. Sensitivity for four of the five categories (inflammatory, ischemia, peripheral neurogenic, and other ranged from 72·0 to 83·1%). For the central mechanism, sensitivity was much lower at 15%. Specificity for the five categories ranged from 72·4% (ischemia) to 98·8% (central). This study provides empirical support for recent findings in the literature that the peripheral components of a PMCS can be implemented consistently in an outpatient pain clinical practice.

Classification of patients with low back-related leg pain: a systematic review

BACKGROUND

The identification of clinically relevant subgroups of low back pain (LBP) is considered the number one LBP research priority in primary care. One subgroup of LBP patients are those with back related leg pain. Leg pain frequently accompanies LBP and is associated with increased levels of disability and higher health costs than simple low back pain. Distinguishing between different types of low back-related leg pain (LBLP) is important for clinical management and research applications, but there is currently no clear agreement on how to define and identify LBLP due to nerve root involvement. The aim of this systematic review was to identify, describe and appraise papers that classify or subgroup populations with LBLP, and summarise how leg pain due to nerve root involvement is described and diagnosed in the various systems.

METHODS

The search strategy involved nine electronic databases including Medline and Embase, reference lists of eligible studies and relevant reviews. Selected papers were appraised independently by two reviewers using a standardised scoring tool.

RESULTS

Of 13,358 initial potential eligible citations, 50 relevant papers were identified that reported on 22 classification systems. Papers were grouped according to purpose and criteria of the classification systems. Five themes emerged: (i) clinical features (ii) pathoanatomy (iii) treatment-based approach (iv) screening tools and prediction rules and (v) pain mechanisms. Three of the twenty two systems focused specifically on LBLP populations. Systems that scored highest following quality appraisal were ones where authors generally included statistical methods to develop their classifications, and supporting work had been published on the systems' validity, reliability and generalisability. There was lack of consistency in how LBLP due to nerve root involvement was described and diagnosed within the systems.

CONCLUSION

Numerous classification systems exist that include patients with leg pain, a minority of them focus specifically on distinguishing between different presentations of leg pain. Further work is needed to identify clinically meaningful subgroups of LBLP patients, ideally based on large primary care cohort populations and using recommended methods for classification system development.

Reliability among clinicians diagnosing low back-related leg pain

PURPOSE

To investigate agreement and reliability among clinicians when diagnosing low back-related leg pain (LBLP) in primary care consulters.

METHODS

Thirty-six patients were assessed by one of six physiotherapists and diagnosed as having either leg pain due to nerve root involvement (sciatica) or referred leg pain. Assessments were video recorded. In part one, the physiotherapists each viewed videos of six patients they had not assessed. In part two, videos were viewed by another six health professionals. All clinicians made an independent differential diagnosis and rated their confidence with diagnosis (range 50-100 %).

RESULTS

In part one agreement was 72 % with fair inter-rater reliability (K = 0.35, 95 % CI 0.07, 0.63). Results for part two were almost identical (K = 0.34, 95 % CI 0.02, 0.69). Agreement and reliability indices improved as diagnostic confidence increased.

CONCLUSION

Reliability was fair among clinicians from different backgrounds when diagnosing LBLP but improved substantially with high confidence in clinical diagnosis.

Sciatica: detection and confirmation by new method

We need to overcome limitations of present assessment and also integrate newer research in our work about sciatica. Inflammation induces changes in the DRG and nerve root. It sensitizes the axons. Nociceptor is a unique axon. It is pseudo unipolar: both its ends, central and peripheral, behave in similar fashion. The nerve in periphery which carries these axons may selectively become sensitive to mechanical pressure--"mechanosensitized," as we coin the phrase. Many pain questionnaires are used and are effective in identifying neuropathic pain solely on basis of descriptors but they do not directly physically correlate nerve root and pain. A thorough neurological evaluation is always needed. Physical examination is not direct pain assessment but testing mobility of nerve root and its effect on pain generation. There is a dogmatic dominance of dermatomes in assessment of leg pain. They are unreliable. Images may not correlate with symptoms and pathology in about 28% of cases. Electrophysiology may be normal in purely inflamed nerve root. Palpation may help in such inflammatory setting to refine our assessment further. Confirmation of sciatica is done by selective nerve root block (SNRB) today but it is fraught with several complications and needs elaborate inpatient and operating room set up. We have used the unique property of the pseudo unipolar axon that both its ends have similar functional properties and so inject along its peripheral end sodium channel blockers to block the basic cause of the mechanosensitization namely upregulated sodium channels in the root or DRG. Thus using palpation we may be able to detect symptomatic nerve in stage of inflammation and with distal end injection, along same inflamed nerve we may be able to abolish and so confirm sciatica. Discussions of sciatica pain diagnosis tend to immediately shift and centre on the affected disc rather than the nerve. Theoretically it may be possible to detect the affected nerve by palpating the nerve and relieve pain moment we desensitize the nerve.

Pain treatment for patients with osteoarthritis and central sensitization

Osteoarthritis is one of the most frequent, disabling, and costly pathologies of modern society. Among the main aims of osteoarthritis management are pain control and functional ability improvement. The exact cause of osteoarthritis pain remains unclear. In addition to the pathological changes in articular structures, changes in central pain processing or central sensitization appear to be involved in osteoarthritis pain. The latter calls for a broader approach to the management of patients with osteoarthritis. Yet, the scientific literature offers scant information addressing the treatment of central sensitization, specifically in patients with osteoarthritis. Interventions such as cognitive-behavioral therapy and neuroscience education potentially target cognitive-emotional sensitization (and descending facilitation), and centrally acting drugs and exercise therapy can improve endogenous analgesia (descending inhibition) in patients with osteoarthritis. Future studies should assess these new treatment avenues.

Expectations of pain and accompanying symptoms during cancer treatment

Patients' experience of cancer pain varies throughout the course of the disease. It is important to recognize that patients may experience more than one type of pain, and pain often occurs in the presence of other symptoms. Controlling pain requires a multi-faceted approach to assessing and treating the underlying mechanisms. This article reviews the pain mechanisms responsible for pain during cancer treatment and how expectations of pain and associated symptoms contribute to the pain experience.