Signs and Symptoms of Myofascial Pain: An International Survey of Pain Management Providers and Proposed Preliminary Set of Diagnostic Criteria.

OBJECTIVE: Myofascial Pain Syndrome (MPS) is highly prevalent in pain medicine, yet there is no "gold standard" or set of validated diagnostic criteria for clinical or research use. A survey collected clinician perspectives on MPS to foster the development of a formal case definition for empirical validation. DESIGN: International survey. METHODS: Clinician members of the International Association for the Study of Pain and the American Academy of Pain Medicine received a survey of the symptoms and signs of MPS and expected response to treatment. Write-in fields were available for each category and to suggest relevant diagnostic studies. RESULTS: Two hundred fourteen responses were received from 4,143 surveys mailed. The most essential components of MPS were tender spots that recreate symptoms when palpated. MPS was also associated with muscle stiffness, decreased range of motion of the affected joints, worsening symptoms with stress, palpable taut band or tender nodule, and referred pain with palpation of the tender spot. Diagnostic studies are reported to be useful for ruling out other pathology, but not to confirm the presence of the condition. CONCLUSIONS: These results were used to propose a set of preliminary diagnostic criteria; expert consensus for case definition and subsequent empirical validation are required for standardization in research and clinical management of MPS.

The osteoarthritis knee model: psychophysical characteristics and putative outcomes.

UNLABELLED: The knee osteoarthritis (KOA) model is a convenient and coherent archetype that is frequently used in pharmaceutical trials of drugs with analgesic and/or anti-inflammatory properties; yet, little is known about its specific pathophysiology. The presumed chronic inflammatory etiology of osteoarthritis suggests that nociceptive processes and neurogenic inflammation predominate in this condition. However, most chronic pain conditions are associated with changes in peripheral and central processing. Recent data corroborate this as an important mechanism in KOA. We compared psychophysical characteristics (including thermal Quantitative Sensory Testing); thermal, mechanical, and functional wind-up; thermal and mechanical aftersensations; and pressure algometry of 37 subjects with KOA with 35 age- and sex-matched controls. A third of the KOA subjects demonstrated hypoesthesia to vibration and the 4.56 von Frey fiber, yet few showed allodynia in their worse knee. The majority of subjects had abnormalities to pinprick (41% were hyperalgesic and 27% were hypoesthetic). Compared to controls, the more painful knee was hypoesthetic to cold detection and had greater thermal wind-up, lower pressure-pain thresholds, thermal and mechanical aftersensations, and twice the pain ratings of controls after stair climb. Substantial intraindividual differences were found in KOA subjects and controls for mechanical wind-up and algometric thresholds. PERSPECTIVE: These results develop the KOA model and suggest mechanistic hypotheses. Certain of these tests may ultimately prove to be responsive, quasi-objective, and quantitative outcomes for research and lend empirical support to the notion of measurable sensitization in osteoarthritis.

Complex regional pain syndrome: practical diagnostic and treatment guidelines, 4th edition.

OBJECTIVE: This is the fourth edition of diagnostic and treatment guidelines for complex regional pain syndrome (CRPS; aka reflex sympathetic dystrophy). METHODS: Expert practitioners in each discipline traditionally utilized in the treatment of CRPS systematically reviewed the available and relevant literature; due to the paucity of levels 1 and 2 studies, less rigorous, preliminary research reports were included. The literature review was supplemented with knowledge gained from extensive empirical clinical experience, particularly in areas where high-quality evidence to guide therapy is lacking. RESULTS: The research quality, clinical relevance, and "state of the art" of diagnostic criteria or treatment modalities are discussed, sometimes in considerable detail with an eye to the expert practitioner in each therapeutic area. Levels of evidence are mentioned when available, so that the practitioner can better assess and analyze the modality under discussion, and if desired, to personally consider the citations. Tables provide details on characteristics of studies in different subject domains described in the literature. CONCLUSIONS: In the humanitarian spirit of making the most of all current thinking in the area, balanced by a careful case-by-case analysis of the risk/cost vs benefit analysis, the authors offer these "practical" guidelines.

Development of a severity score for CRPS.

The clinical diagnosis of Complex Regional Pain Syndrome (CRPS) is a dichotomous (yes/no) categorization necessary for clinical decision-making. However, such dichotomous diagnostic categories do not convey an individual's subtle and temporal gradations in severity of the condition, and have poor statistical power when used as an outcome measure in research. This study evaluated the validity and potential utility of a continuous type score to index severity of CRPS. Psychometric and medical evaluations were conducted in 114 CRPS patients and 41 non-CRPS neuropathic pain patients. Based on the presence/absence of 17 clinically-assessed signs and symptoms of CRPS, an overall CRPS Severity Score (CSS) was derived. The CSS discriminated well between CRPS and non-CRPS patients (p<.001), and displayed strong associations with dichotomous CRPS diagnoses using both IASP diagnostic criteria (Eta=0.69) and proposed revised criteria (Eta=0.77-0.88). Higher CSS was associated with significantly higher clinical pain intensity, distress, and functional impairments, as well as greater bilateral temperature asymmetry and thermal perception abnormalities (p's<.05). In an archival prospective dataset, increases in anxiety and depression from pre-surgical baseline to 4 weeks post-knee arthroplasty were found to predict significantly higher CSS at 6- and 12-month follow-up (p's<.05). Results indicate the CSS corresponds with and complements currently accepted dichotomous diagnostic criteria for CRPS, and support its validity as an index of CRPS severity. Its utility as an outcome measure in research studies is also suggested, with potential statistical advantages over dichotomous diagnostic criteria.

Negligible analgesic tolerance seen with extended release oxymorphone: a post hoc analysis of open-label longitudinal data.

OBJECTIVE: To examine the development of analgesic tolerance in patients on oxymorphone extended-release (OxymER). DESIGN: Post hoc analysis of data from a previously conducted prospective 1 year multi-center open-label extension study in which patients were able to titrate as needed. PATIENTS: Sample of 153 hip and knee osteoarthritis (OA) subjects on OxymER. Primary analyses were limited to study completers (n = 62) due to the large amount of missing data for the noncompleters (n = 91). OUTCOME MEASURES: Main outcome measures included OxymER doses (pill counts) and pain intensity ratings using a visual analog scale at monthly visits. RESULTS: There were significant dose increases from weeks 1 to 2 and 2 to 6 (P < 0.05). Doses stabilized around week 6, suggesting the completion of what we defined as "titration." Both doses and pain ratings were stable when this titration phase was excluded from the analysis (P = 0.751; P = 0.056, respectively). Only 28% of the patients had any dose changes following this titration. While there was a significantly greater dose at week 52 compared with week 10 (P = 0.010), the increase in dose became insignificant after excluding four subjects who required two dose increases (P = 0.103). CONCLUSIONS: The results showed that most of the titration/dose stabilization changes occurred within the first 10 weeks. A minority (28%) of subjects required dosage increases after this (defined) titration period. Pain reports stabilized statistically after 2 weeks. The findings of this post hoc analysis suggest a lack of opioid tolerance in the majority (72%) of these OA patients who completed this study following a defined titration period on OxymER. SUMMARY: This post hoc analysis of oxymorphone ER consumption in osteoarthritis pain vs pain report showed that most dose changes occurred during an initial "titration period" as defined. Following this titration few subjects increased dose and analgesia remained stable. These findings suggest a lack of longitudinal opioid tolerance in the majority of those OA subjects who completed the trial.

Do omega-6 and trans fatty acids play a role in complex regional pain syndrome? A pilot study.

OBJECTIVES: The study aims to compare the omega-6 (n-6) and omega-3 (n-3) highly unsaturated fatty acids (HUFA), and trans fatty acid (trans FA) status of Complex Regional Pain Syndrome (CRPS) patients to pain-free controls. DESIGN: Case control study. Setting. The setting was at a multidisciplinary rehabilitation center. PATIENTS: Twenty patients that met the Budapest research diagnostic criteria for CRPS and 15 pain-free control subjects were included in this study. Outcome Measures. Fasting plasma fatty acids were collected from all participants. In CRPS patients, pain was assessed using the McGill Pain Questionnaire-Short Form. In addition, results from the perceived disability (Pain Disability Index), pain-related anxiety (Pain Anxiety Symptom Scale Short Form), depression (Center for Epidemiologic Studies Depression Scale Short Form), and quality of life (Short Form-36 [SF-36]) were evaluated. RESULTS: Compared with controls, CRPS patients demonstrated elevated concentrations of n-6 HUFA and trans FA. No differences in n-3 HUFA concentrations were observed. Plasma concentrations of the n-6 HUFA docosatetraenoic acid were inversely correlated with the "vitality" section of the SF-36. Trans FA concentrations positively correlated with pain-related disability and anxiety. CONCLUSION: These pilot data suggest that elevated n-6 HUFA and trans FA may play a role in CRPS pathogenesis. These findings should be replicated, and more research is needed to explore the clinical significance of low n-6 and trans FA diets with or without concurrent n-3 HUFA supplementation, for the management of CRPS.

Validation of proposed diagnostic criteria (the "Budapest Criteria") for Complex Regional Pain Syndrome.

Current IASP diagnostic criteria for CRPS have low specificity, potentially leading to overdiagnosis. This validation study compared current IASP diagnostic criteria for CRPS to proposed new diagnostic criteria (the "Budapest Criteria") regarding diagnostic accuracy. Structured evaluations of CRPS-related signs and symptoms were conducted in 113 CRPS-I and 47 non-CRPS neuropathic pain patients. Discriminating between diagnostic groups based on presence of signs or symptoms meeting IASP criteria showed high diagnostic sensitivity (1.00), but poor specificity (0.41), replicating prior work. In comparison, the Budapest clinical criteria retained the exceptional sensitivity of the IASP criteria (0.99), but greatly improved upon the specificity (0.68). As designed, the Budapest research criteria resulted in the highest specificity (0.79), again replicating prior work. Analyses indicated that inclusion of four distinct CRPS components in the Budapest Criteria contributed to enhanced specificity. Overall, results corroborate the validity of the Budapest Criteria and suggest they improve upon existing IASP diagnostic criteria for CRPS.