[Chronic Pain: Definition/Conception/Classification of Pain].

Understanding what pain is necessary to understand the pathomechanisms of chronic pain. The International Association for the Study of Pain (IASP) defines pain as "An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage" and its further states that pain is a personal experience, influenced to varying degrees by biological, psychological, and social factors. It also mentions that person learn the concept of the pain through life experiences, and that it does not always play an adaptive role and has a negative impact on our physical, social, and psychological health. In order to classify chronic pain, IASP created a coding system in ICD11 that focuses on chronic secondary pain, which has clear organic factors, and chronic primary pain, which is difficult to explain from the organic aspect alone. When considering pain treatment, it is necessary to consider three pain mechanisms, including nociceptive pain, neuropathic pain, and nociplastic pain, which is a condition in which the patient feels strong pain due to sensitization of the nervous system.

Characteristics of clusters with contrasting relationships between central sensitization-related symptoms and pain.

The central sensitization inventory (CSI) evaluates the central sensitization (CS)-related symptoms associated with increased pain sensitivity. However, the CSI includes items that are not directly related to pain. In this study, 146 patients with pain were classified into subgroups by k-means cluster analysis based on the short form of the central sensitization inventory (CSI9) and pain scores. In addition, inter-group and multiple comparisons were performed to examine the characteristics of each group. As a result of this study, there were three subgroups (clusters 1, 2, and 3) in which the CSI9 and pain intensity were both low, moderate, and high, and one subgroup (cluster 4) in which only CSI9 was high and pain intensity was low. Two subgroups with high CSI9 scores but contrasting pain intensities (clusters 3 and 4) were extracted; the pattern of CS-related symptoms in these two groups was very similar, with no differences in most of the non-pain factors. It is necessary to consider these points when interpreting the clinical condition of a patient with pain when using the assessment of CS-related symptoms.

Radiofrecuencia pulsada del ganglio de la raíz dorsal para el dolor radicular lumbosacro: una revisión narrativa / Dorsal root ganlion pulsed radiofrequency for lumbosacral radicular pain: a narrative review

Objetivo: La radiofrecuencia pulsada constituye la variante no destructiva de la termolesión por radiofrecuencia. Una opción terapéutica en pacientes con síndrome radicular lumbosacro refractario a esteroides epidurales es la aplicación de RFP en el ganglio de la raíz dorsal. Si bien el mecanismo íntimo de acción de la misma no está del todo esclarecido, se plantea como una técnica de neuromodulación. La evidencia de la eficacia de esta intervención es débil por diversos factores: insuficientes estudios clínicos randomizados, el bajo tamaño muestral utilizado en los mismos, las controversias sobre algunos aspectos técnicos en la aplicación de la RFP, la selección incorrecta de pacientes, la presencia o no de dolor neuropático, etc. Nuestro objetivo es presentar una revisión de la evidencia de la eficacia y el perfil de seguridad de la RFP del GRD en pacientes con SRLS refractario. Los aspectos clínicos relacionados con la técnica y sus posibles mecanismos de acción son también reseñados. Material y métodos: Realizamos una búsqueda bibliográfica en MEDLINE (Pubmed), Google Scholar, Scopus, CINAHL, Embase, Cochrane y Fisterra (guías clínicas) en inglés y español para todos los años disponibles con los términos "Dorsal Root Ganglion pulsed radiofrequency" y "lumbar" o "lumbosacral radicular pain" en idioma inglés y español. La evaluación fue realizada por los dos autores de manera independiente. Resultados: Presentamos el análisis de ocho estudios prospectivos randomizados y nueve de cohorte única de tipo antes y después, de pacientes con dolor radicular lumbosacro refractario cuyos objetivos fueron la evaluación de la eficacia y seguridad de la técnica. Conclusiones: La RFP del GRD podría ser una opción terapéutica útil en el SRLS refractario, pudiendo considerarse sus resultados como preliminares, y deberán ser confirmados por estudios prospectivos randomizados con criterios de selección homogéneos y mayor número de pacientes.(AU)

Objective: Pulsed radiofrequency can be a non-destructive option compared with the thermical lesion produced by continuous radiofrequency. The application of PRF of the dorsal root ganglion is a therapeutic tool in patients with Lumbosacral Radicular Syndrome refractory to epidural steroids injections. The mechanisms of action are not clear yet and a neuromodulation process is proposed. The evidence of the efficacy of this intervention is of low quality, due to several factors. Our objective is to present a review of the evidence of the efficacy and safety profile of the DRG RFP. The clinical aspects related to the technique and its possible mechanisms of action are also reviewed. Material and methods: A bibliographic review was performed in MEDLINE (Pubmed), Google Scholar, Scopus, CINAHL, Embase, Cochrane and Fisterra (clinical guidelines) of articles in English and Spanish, during the available years with the terms: "Dorsal Root Ganglion pulsed radiofrequency" and "lumbar" or "lumbosacral radicular pain" in English and Spanish. Bibliographic review was carried out by the 2 authors independently. Results: We present the analysis of eight prospective, randomized studies and nine cohort studies, with a before and after type of design, in which the study of efficacy and safety was proposed as the main objective. Conclusions: This review suggested that PRF of the DRG can be a good therapeutic option in patients with refractory LRS. Larger, blinded, prospective and randomized controlled trials are needed to support this statement.(AU)

Muscle network topology analysis for the classification of chronic neck pain based on EMG biomarkers extracted during walking.

Neuromuscular impairments are frequently observed in patients with chronic neck pain (CNP). This study uniquely investigates whether changes in neck muscle synergies detected during gait are sensitive enough to differentiate between people with and without CNP. Surface electromyography (EMG) was recorded from the sternocleidomastoid, splenius capitis, and upper trapezius muscles bilaterally from 20 asymptomatic individuals and 20 people with CNP as they performed rectilinear and curvilinear gait. Intermuscular coherence was computed to generate the functional inter-muscle connectivity network, the topology of which is quantified based on a set of graph measures. Besides the functional network, spectrotemporal analysis of each EMG was used to form the feature set. With the use of Neighbourhood Component Analysis (NCA), we identified the most significant features and muscles for the classification/differentiation task conducted using K-Nearest Neighbourhood (K-NN), Support Vector Machine (SVM), and Linear Discriminant Analysis (LDA) algorithms. The NCA algorithm selected features from muscle network topology as one of the most relevant feature sets, which further emphasize the presence of major differences in muscle network topology between people with and without CNP. Curvilinear gait achieved the best classification performance through NCA-SVM based on only 16 features (accuracy: 85.00%, specificity: 81.81%, and sensitivity: 88.88%). Intermuscular muscle networks can be considered as a new sensitive tool for the classification of people with CNP. These findings further our understanding of how fundamental muscle networks are altered in people with CNP.

Hábitos de prescripción para el abordaje del dolor neuropático en España: resultados de la encuesta del grupo de trabajo de dolor neuropático de la Sociedad Española del Dolor / Prescribing habits for neuropathic pain management in Spain: results of the survey of the neuropathic pain working group of the Spanish Pain Society

Objetivos: Hace más de diez años que salieron al mercado los últimos fármacos con indicación en las guías internacionales de dolor neuropático (DN). Estas recomiendan iniciar con monoterapia y sitúan el tratamiento combinado en el segundo escalón. Un considerable número de pacientes no alcanza un suficiente alivio del dolor o mejora de su calidad de vida con los fármacos disponibles. Bajo esta perspectiva, el Grupo de Trabajo (GT) de DN de la Sociedad Española del Dolor (SED) diseñó una encuesta para el abordaje del DN mediante fármacos, técnicas intervencionistas y tratamientos fuera de indicación en nuestro medio. En este artículo se analiza solo la parte de tratamientos farmacológicos. Material y métodos: Estudio descriptivo mediante un cuestionario autoadministrado difundido por correo electrónico a los socios de la SED en dos oleadas durante 2019. Al inicio del cuestionario se realizaba una pregunta de selección sobre si utilizaban o no tratamientos fuera de ficha técnica o fuera de indicación. Solo los que respondieron afirmativamente procedieron a todo el conjunto de preguntas. Este se dividió en los siguientes bloques: antiepilépticos, antidepresivos, antipsicóticos, anestésicos, anti-nmda, cannabinoides, naltrexona, tratamientos tópicos, toxina botulínica, polifarmacia y tratamientos fuera de ficha. Dentro de la sección de tratamientos tópicos se incluyó la toxina botulínica. Resultados: La tasa de respuesta fue del 13,82 %, siendo del 10,05 % una vez descartadas las no válidas. El 21 % comienzan el tratamiento del DN con polifarmacia y un 43 % lo hace cuando no responden a una primera línea. El 40 % de los encuestados opinan que no hay evidencia suficiente para el uso de polifarmacia. El 70 % de los participantes trataban hasta un 30 % de sus pacientes con DN con fármacos fuera de indicación. El 23,3 % utilizaban medicamentos fuera de ficha técnica entre el 40 % y el 60 % de los pacientes con DN y un 6,6 % lo hacía en un 70-90 %...(AU)

Objectives: Latest drugs with an indication for neuropathic pain (NP) in the international guidelines came onto the market more than ten years ago. They recommend starting with monotherapy and place the combined treatment in the second step. A considerable number of patients do not achieve sufficient pain relief or improvement in their quality of life with the available drugs. From this perspective, the NP Working Group (WG) of the Spanish Pain Society (SED) designed a survey to address how NP drugs, off-label treatments and interventional techniques are being used in our setting. In this article we will only discuss the pharmacological treatment options.Material and methods: Descriptive study using a self-administered questionnaire distributed by email to SED members in two waves during 2019. At the beginning of the questionnaire, a selection question was asked whether or not they used non-technical or off-label treatments. Only those who answered affirmatively proceeded to the entire set of questions. It was divided into the following blocks: antiepileptics, antidepressants, antipsychotics, anesthetics, anti-nmda, cannabinoids, naltrexone, topical treatments, botulinum toxin, polypharmacy and off-label treatments. Botulinum toxin was included in the topical treatments section. Results: The response rate was 13.82 %, being 10.05 % once the invalid ones had been ruled out. 21 % begin the treatment of NP directly on polypharmacy and 43 % do so when they do not respond to a first line. 40 % of those surveyed think that there is insufficient evidence for the use of polypharmacy. 70 % of the participants treated up to 30 % of their NP patients with off-label drugs. 23.3 % used off-label me­dications in between 40 % and 60 % of patients with NP and 6.6 % did so in 70-90 % of patients...(AU)

Distinguishing chronic low back pain in young adults with mild to moderate pain and disability using trunk compliance.

Chronic low back pain (cLBP) rates among younger individuals are rising. Although pain and disability are often less severe, underlying changes in trunk behavior may be responsible for recurrence. We examine the biomarker capacity of a simple Trunk Compliance Index (TCI) to distinguish individuals with and without cLBP. A random subset (n = 49) of the RELIEF RCT were matched to healthy controls for sex, age, height and weight. We measured TCI (as displacement/ weight-normalized perturbation force) using anthropometrically-matched, suddenly-applied pulling perturbations to the trunk segment, randomized across three planes of motion (antero-posterior, medio-lateral, and rotational). Mean differences between cLBP, sex and perturbation direction were assessed with repeated-measures analysis of variance. Discriminatory accuracy of TCI was assessed using Receiver Operator Characteristic (ROC) analysis. Baseline characteristics between groups were equivalent (x̅ [range]): sex (57% female / group), age (23.0 [18-45], 22.8 [18-45]), height, cm (173.0 [156.5-205], 171.3 [121.2-197], weight, kg (71.8 [44.5-116.6], 71.7 [46.8-117.5]) with cLBP associated with significantly lower TCI for 5 of 6 directions (range mean difference, - 5.35: - 1.49, range 95% CI [- 6.46: - 2.18 to - 4.35: - 0.30]. Classification via ROC showed that composite TCI had high discriminatory potential (area under curve [95% CI], 0.90 [0.84-0.96]), driven by TCI from antero-posterior perturbations (area under curve [95% CI], 0.99 [0.97-1.00]). Consistent reductions in TCI suggests global changes in trunk mechanics that may go undetected in classic clinical examination. Evaluation of TCI in younger adults with mild pain and disability may serve as a biomarker for chronicity, leading to improved preventative measures in cLBP.Trial Registration and Funding RELIEF is registered with clinicaltrials.gov (NCT01854892) and funded by the NIH National Center for Complementary & Integrative Health (R01AT006978).

Chronic pain (primary and secondary) in over 16s: assessment of all chronic pain and management of chronic primary pain

This guideline covers assessing all chronic pain (chronic primary pain, chronic secondary pain, or both) and managing chronic primary pain in people aged 16 years and over. Chronic primary pain is pain with no clear underlying cause, or pain (or its impact) that is out of proportion to any observable injury or disease. This guideline should be used alongside NICE guidelines for other chronic pain conditions, including the NICE guidelines on headaches, low back pain and sciatica, rheumatoid arthritis, osteoarthritis, spondyloarthritis, endometriosis, neuropathic pain and irritable bowel syndrome.

Nerve Pain after Burn Injury: A Proposed Etiology-Based Classification.

BACKGROUND: Understanding the mechanism of nerve injury may facilitate managing burn-related nerve pain. This proposed classification, based on cause of nerve injury, was developed to enhance the understanding and management of burn-related nerve pain. METHODS: This retrospective investigation included patients aged 15 years or older admitted to the burn center from 2014 to 2019. Burn-related nerve pain was patient-reported and clinically assessed as pain 6 months or more after burn injury, unrelated to preexisting illnesses/medications. The pain classification consisted of direct nerve injury, nerve compression, electrical injury, and nerve dysfunction secondary to systemic injury. The four categories were statistically analyzed between groups, using 52 variables. RESULTS: Of the 1880 consecutive burn patients, 113 developed burn-related nerve pain and were eligible for validation of the classification: direct nerve injury, n = 47; nerve compression, n = 12; electrical injury, n = 7; and nerve dysfunction secondary to systemic injury, n = 47. Factors, significantly increased, that distinguished one category from another were as follows: for direct nerve injury, continuous symptoms (p < 0.001), refractory nerve release response (p < 0.001), nerve repair (p < 0.001), and pruritus (p < 0.001); for nerve compression, Tinel signs (p < 0.001), shooting pain (p < 0.001), numbness (p = 0.003), intermittent symptoms (p < 0.001), increased percentage total body surface area burned (p = 0.019), surgical procedures (p < 0.001), and nerve release (p < 0.001); and for electrical injury, Tinel sign (p < 0.001), intermittent symptoms (p = 0.002), amputations (p = 0.002), fasciotomies (p < 0.001), and nerve release (p < 0.001). Nerve dysfunction secondary to systemic injury was distinguished by significantly less Tinel signs (p < 0.001), shooting pain (p < 0.001), numbness and tingling (p < 0.001), pruritus (p < 0.001), fascial excision (p = 0.004), skin grafts (p < 0.001), amputation (p = 0.004), nerve releases (p < 0.001), and third-degree burns (p = 0.002). CONCLUSION: A classification consisting of direct nerve injury, nerve compression, electrical injury, and nerve dysfunction secondary to systemic injury is presented that may guide patient management and research methods, with the goal of improving pain outcomes in burn-related nerve pain.

Less is More: Five-item Neck Disability Index to Assess Chronic Neck Pain Patients in Brazil.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: The aim of this study was to assess the structural validity of the Brazilian version of the Neck Disability Index (NDI) in patients with chronic neck pain. SUMMARY OF BACKGROUND DATA: NDI is widely used in clinical and scientific contexts, although its structure has not been evaluated in the Brazilian version. METHODS: Native Brazilian Portuguese speakers, aged ≥18 years, with neck pain complaint of at least 3 months, and minimal pain rating of 3 points at rest or during neck movements were included. Exploratory factorial analysis (EFA) and confirmatory factorial analysis (CFA) were used. In EFA, the adequacy of the model was assessed using Bartlett test of sphericity and Kaiser-Meyer-Olkin test. In CFA, the goodness-of-fit was assessed by the indices: root mean square error of approximation with 90% of confidence interval, comparative fit index, Tucker-Lewis Index, standardized root mean square residual, and χ2/degree of freedom. Akaike information criterion (AIC) and Bayesian information criterion (BIC) were considered to compare the models. RESULTS: Two hundred fifty-four participants with chronic neck pain were included. The NDI model with one domain and five items presented the most adequate goodness-of-fit indexes and the lowest values of AIC and BIC, when compared with models with one domain and 10, eight, or seven items, and with the model with two domains and 10 items. CONCLUSION: In the Brazilian context, the NDI version with one domain and five items (personal care, concentration, work, driving, and recreation) presents the best structure according to the factorial analysis.Level of Evidence: 5.

Triaging Interventional Pain Procedures During COVID-19 or Related Elective Surgery Restrictions: Evidence-Informed Guidance from the American Society of Interventional Pain Physicians (ASIPP).

BACKGROUND: The COVID-19 pandemic has worsened the pain and suffering of chronic pain patients due to stoppage of "elective" interventional pain management and office visits across the United States. The reopening of America and restarting of interventional techniques and elective surgical procedures has started. Unfortunately, with resurgence in some states, restrictions are once again being imposed. In addition, even during the Phase II and III of reopening, chronic pain patients and interventional pain physicians have faced difficulties because of the priority selection of elective surgical procedures.Chronic pain patients require high intensity care, specifically during a pandemic such as COVID-19. Consequently, it has become necessary to provide guidance for triaging interventional pain procedures, or related elective surgery restrictions during a pandemic. OBJECTIVES: The aim of these guidelines is to provide education and guidance for physicians, healthcare administrators, the public and patients during the COVID-19 pandemic. Our goal is to restore the opportunity to receive appropriate care for our patients who may benefit from interventional techniques. METHODS: The American Society of Interventional Pain Physicians (ASIPP) has created the COVID-19 Task Force in order to provide guidance for triaging interventional pain procedures or related elective surgery restrictions to provide appropriate access to interventional pain management (IPM) procedures in par with other elective surgical procedures. In developing the guidance, trustworthy standards and appropriate disclosures of conflicts of interest were applied with a section of a panel of experts from various regions, specialties, types of practices (private practice, community hospital and academic institutes) and groups. The literature pertaining to all aspects of COVID-19, specifically related to epidemiology, risk factors, complications, morbidity and mortality, and literature related to risk mitigation and stratification was reviewed. The evidence -- informed with the incorporation of the best available research and practice knowledge was utilized, instead of a simplified evidence-based approach. Consequently, these guidelines are considered evidence-informed with the incorporation of the best available research and practice knowledge. RESULTS: The Task Force defined the medical urgency of a case and developed an IPM acuity scale for elective IPM procedures with 3 tiers. These included urgent, emergency, and elective procedures. Examples of urgent and emergency procedures included new onset or exacerbation of complex regional pain syndrome (CRPS), acute trauma or acute exacerbation of degenerative or neurological disease resulting in impaired mobility and inability to perform activities of daily living. Examples include painful rib fractures affecting oxygenation and post-dural puncture headaches limiting the ability to sit upright, stand and walk. In addition, emergency procedures include procedures to treat any severe or debilitating disease that prevents the patient from carrying out activities of daily living. Elective procedures were considered as any condition that is stable and can be safely managed with alternatives. LIMITATIONS: COVID-19 continues to be an ongoing pandemic. When these recommendations were developed, different stages of reopening based on geographical regulations were in process. The pandemic continues to be dynamic creating every changing evidence-based guidance. Consequently, we provided evidence-informed guidance. CONCLUSION: The COVID-19 pandemic has created unprecedented challenges in IPM creating needless suffering for pain patients. Many IPM procedures cannot be indefinitely postponed without adverse consequences. Chronic pain exacerbations are associated with marked functional declines and risks with alternative treatment modalities. They must be treated with the concern that they deserve. Clinicians must assess patients, local healthcare resources, and weigh the risks and benefits of a procedure against the risks of suffering from disabling pain and exposure to the COVID-19 virus.

Evolution of bodily distress disorders.

PURPOSE OF REVIEW: The nomenclature and classification of somatoform disorders have undergone revisions in the fifth edition of the Diagnostic and Statistical Manual (DSM 5) and the upcoming eleventh edition of the International Classification of Diseases (ICD-11). The present review describes the changes that have evolved and highlight the possible challenges. RECENT FINDINGS: Bodily distress disorders replace the term somatoform disorders. The emphasis on the symptoms to be medically unexplained has been removed. The need to have a certain number of symptoms associated with different organ systems has made way to the presence of one or more distressing bodily symptoms. The focus on psychological aspects like excessive attention, thoughts, and behaviors associated with bodily symptoms have been added to make it a more diagnosis of inclusion rather than exclusion. An additional qualifier of severity has been added, which highlights the importance of impairment associated with these symptoms. SUMMARY: The diagnostic criteria for bodily distress disorders is a step towards making the diagnostic criteria clinically useful and appears to be applicable across the healthcare settings. However, the ability to discern this diagnosis with the newly revised classification of chronic pain and the possibility of over psychologizing the medical disorders need to be researched.

Description and classification of postpartum chronic pain: A multicentric prospective study.

INTRODUCTION: To classify persistent perineal and pelvic postpartum pain using the classification usually employed in chronic pelvic pain. MATERIAL AND METHOD: Prospective observational study including all women who have consulted an algologist or gynecologist at one of the six French centers for a chronic pain (superior or equal to 3 months) spontaneous linked by the mother with her childbirth were included. During semi-directed interviews, a questionnaire regarding sociodemographic factors and detailed questions about pain were collected. Then, pelvic and perineal pain were classified into 7 pain syndromes: pelvic sensitization (Convergences PP criteria), complex regional pain syndrome (Budapest criteria), pudendal or cluneal neuralgia (Nantes criteria), neuroma, thoraco-lumbar junction syndrome, myofascial pain (muscle trigger zone), fibromyalgia (American College of Rheumatology criteria). The principal objective of this study is to assess the prevalence of each painful disorder. The secondary aims were the description of socio-demographic factors and clinical characteristics of this population, identify the related symptoms and the impact on daily function associated with the chronic pelvic or perineal postpartum pain. RESULTS: 40 women with chronic pelvic or perineal pain spontaneously linked with childbirth were included. 78 % experienced pain for more than 12 months. A large majority had a vaginal birth (95 %) with perineal suture (90 %) and severe acute pain within the first week postpartum (62 %). Postpartum pain impacted participant's sexual activity (80 %), micturition (28 %) and defecation (38 %). In the sample, 17 cases of neuroma, 6 patients with pudendal or cluneal neuralgia, 13 patients with pelvic sensitization and 2 cases of fibromyalgia were identified. Complex regional pain syndrome was diagnosed in 8 patients, and myofascial pain in 11 women, and only 1 patient had thoraco-lumbar junction syndrome. Neuropathic pain was found in 31 participants (77.5 %) according to DN4 criteria. DISCUSSION: The classification scheme proposed in this study may be a very useful tool to investigate postpartum pelvic and perineal pain and to propose a treatment.

Factors Influencing Pain Dimensions in Patients with Chronic Tension-Type Headache: An Exploratory Survey.

BACKGROUND: Chronic tension type headache (CTTH) is one of the common cause of hospital visits among adolescents and adults. Chronic tension type headache produces pain, sleep disturbances, and disability among patients leading to a poor quality of life. Knowledge pattern of headache and various associated factors will aid appropriate management. AIMS: To identify the headache dimensions and their various influencing factors among patients of chronic tension-type headache. METHODS: Using consecutive sampling techniques, 169 patients with chronic tension-type headache were recruited in this cross-sectional survey. Approval was obtained from the Institute's Ethics Committee. The Wong-Baker Foundation Pain intensity scale was used to assess the pain severity. RESULTS: A pain severity score of 6 out of 10 was reported by 56% of the patients, and the mean pain score reported by the patients was 6.62 ± 1.16. The mean weekly headache frequency was 4.95 ± 0.38, and the mean daily headache duration was 8.68 ± 1.68 hours. Significantly more patients who are married, patients who had a duration of illness less than two years, and patients who were treated with only analgesics reported higher headache severity. Higher headache frequency was reported by significantly more patients who were male, married, from a nuclear family, educated, unskilled laborers or employed, urban inhabitants, or only on analgesics, or had illness duration less than two years. Headache duration was significantly higher in patients who were unskilled laborers or only on analgesics, or had illness duration less than two years. CONCLUSIONS: Patients with chronic tension-type headache experience moderate to high severity of headache, along with substantial duration and frequency, an outcome that was associated with various lifestyle-related factors that can result in stress. Lifestyle modification and nonpharmacological management are thus essential to reduce the severity, frequency, and duration of headache in patients with a chronic tension-type headache and medication overuse.

Diagnosis of fibromyalgia: comparison of the 2011/2016 ACR and AAPT criteria and validation of the modified Fibromyalgia Assessment Status.

OBJECTIVE: To compare the concordance of the three diagnostic criteria, respectively the 2011 ACR criteria (ACR 2011 Cr), the ACR 2016 criteria (ACR 2016 Cr) and the Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks (ACTTION)-APS Pain Taxonomy criteria (AAPT Cr), and to explore the performance of an additional set of criteria, the modified Fibromyalgia Assessment Status (FAS 2019 modCr), in the diagnosis of FM syndrome. METHODS: Consecutive patients with chronic widespread pain, referred by the primary care setting, underwent rheumatologic assessment that established the presence or not of FM and were investigated through the four sets of proposed criteria. For the FAS 2019 modCr, discriminant validity to distinguish patients with FM and non-FM was assessed with receiver operating characteristic curve analysis. RESULTS: A total of 732 (405 with FM and 327 with other common chronic pain problems) patients were evaluated. Against the clinical diagnosis of FM, the sensitivity, specificity and correct classification were, respectively: 79.8, 91.7 and 85.1% for ACR 2011 Cr; 78, 90.5 and 83.6% for the ACR 2016 Cr; and 73.8, 91.7 and 81.8% for the AAPT Cr. The alternative set, proposed on the FAS 2019 modCr, provided a maximal diagnostic accuracy with a score ≥20 (Youden's index), with a sensitivity of 84.2%, specificity 89.0% and positive likelihood ratio 7.65. CONCLUSION: There is a considerable agreement between criteria-based diagnoses of FM, although the AAPT Cr perform least well in terms of percentage of correct classification. The FAS 2019 modCr had comparable characteristics.

Chronic orofacial pain.

While pain chronicity in general has been defined as pain lasting for more than 3 months, this definition is not useful in orofacial pain (OFP) and headache (HA). Instead, chronicity in OFP and HA is defined as pain occurring on more than 15 days per month and lasting for more than 4 h daily for at least the last 3 months. This definition excludes the periodic shortlasting pains that often recur in the face and head, but are not essentially chronic. Although the headache field has adopted this definition, chronic orofacial pain is still poorly defined. In this article, we discuss current thinking of chronicity in pain and examine the term 'chronic orofacial pain' (COFP). We discuss the entities that make up COFP and analyze the term's usefulness in clinical practice and epidemiology.

Initial classification of low back and leg pain based on objective functional testing: a pilot study of machine learning applied to diagnostics.

OBJECTIVE: The five-repetition sit-to-stand (5R-STS) test was designed to capture objective functional impairment and thus provided an adjunctive dimension in patient assessment. The clinical interpretability and confounders of the 5R-STS remain poorly understood. In clinical use, it became apparent that 5R-STS performance may differ between patients with lumbar disk herniation (LDH), lumbar spinal stenosis (LSS) with or without low-grade spondylolisthesis, and chronic low back pain (CLBP). We seek to evaluate the extent of diagnostic information contained within 5R-STS testing. METHODS: Patients were classified into gold standard diagnostic categories based on history, physical examination, and imaging. Crude and adjusted comparisons of 5R-STS performance were carried out among the three diagnostic categories. Subsequently, a machine learning algorithm was trained to classify patients into the three categories using only 5R-STS test time and patient age, gender, height, and weight. RESULTS: From two prospective studies, 262 patients were included. Significant differences in crude and adjusted test times were observed among the three diagnostic categories. At internal validation, classification accuracy was 96.2% (95% CI 87.099.5%). Classification sensitivity was 95.7%, 100%, and 100% for LDH, LSS, and CLBP, respectively. Similarly, classification specificity was 100%, 95.7%, and 100% for the three diagnostic categories. CONCLUSION: 5R-STS performance differs according to the etiology of back and leg pain, even after adjustment for demographic covariates. In combination with machine learning algorithms, OFI can be used to infer the etiology of spinal back and leg pain with accuracy comparable to other diagnostic tests used in clinical examination. These slides can be retrieved under Electronic Supplementary Material.