Pain medicine training resources: Module 3

Objective: To summarize and to analyze the available literature on the efficacy of intra-articular injections of corticosteroids for low back pain.

Design: Publications, in English, French, and German, were obtained that reported the proportions of patients who obtained complete relief of pain following intra-articular steroids, and that provided any form of follow-up. These publications were analyzed to determine the rationale, indications, and outcomes of the treatment.

Results: The only rationale for intra-articular steroids appears to be the expectation that they should work. The most commonly used indication has been back pain, for which no specific diagnosis has been made. When the results of observational studies are pooled, they paint a picture of impressive immediate responses, but a rapid decay of outcomes by three and six months. Initial responses, however, are dissonant with the literature from controlled studies of the prevalence of lumbar zygapophysial joint pain. Moreover, controlled trials have shown that there is no attributable effect to the injection of steroids.

Conclusion: The apparent efficacy of lumbar intra-articular steroids is no greater than that of a sham injection. There is no justification for the continued use of this intervention. Better outcomes can be achieved with deliberate placebo therapy.

Abstract
Background and purpose: Degenerative changes are commonly found in spine imaging but often occur in pain-free individuals as well as those with back pain. We sought to estimate the prevalence, by age, of common degenerative spine conditions by performing a systematic review studying the prevalence of spine degeneration on imaging in asymptomatic individuals.

Materials and methods: We performed a systematic review of articles reporting the prevalence of imaging findings (CT or MR imaging) in asymptomatic individuals from published English literature through April 2014. Two reviewers evaluated each manuscript. We selected age groupings by decade (20, 30, 40, 50, 60, 70, 80 years), determining age-specific prevalence estimates. For each imaging finding, we fit a generalized linear mixed-effects model for the age-specific prevalence estimate clustering in the study, adjusting for the midpoint of the reported age interval.

Results: Thirty-three articles reporting imaging findings for 3110 asymptomatic individuals met our study inclusion criteria. The prevalence of disk degeneration in asymptomatic individuals increased from 37% of 20-year-old individuals to 96% of 80-year-old individuals. Disk bulge prevalence increased from 30% of those 20 years of age to 84% of those 80 years of age. Disk protrusion prevalence increased from 29% of those 20 years of age to 43% of those 80 years of age. The prevalence of annular fissure increased from 19% of those 20 years of age to 29% of those 80 years of age.

Conclusions: Imaging findings of spine degeneration are present in high proportions of asymptomatic individuals, increasing with age. Many imaging-based degenerative features are likely part of normal aging and unassociated with pain. These imaging findings must be interpreted in the context of the patient's clinical condition.

Abstract
Low back pain is the leading worldwide cause of years lost to disability and its burden is growing alongside the increasing and ageing population.1 Because these population shifts are more rapid in low-income and middle-income countries, where adequate resources to address the problem might not exist, the effects will probably be more extreme in these regions. Most low back pain is unrelated to specific identifiable spinal abnormalities, and our Viewpoint, the third paper in this Lancet Series,2,3 is a call for action on this global problem of low back pain.

Abstract
Background: The superiority of transforaminal epidural steroid injections (TFESI) vs. interlaminar epidural steroid injections (ILESI) for treating unilateral lumbosacral radicular pain (LSRP) is unproven.

Objective: To assess studies comparing TFESI to ILESI for unilateral LSRP for pain relief and functional improvement.

Study design: Systematic review of comparative studies.

Methods: A systematic literature search was conducted using the Cochrane Central Register of Controlled Trials, PubMed, and Scopus databases for trials reported in English. Studies meeting the Cochrane Review criteria for randomized trials and the AHCQ criteria for observational studies were included. Evidence was graded using the USPSTF classification.

Results: Five (prospective) and 3 (retrospective) studies were included assessing 506 patients. Statistical analysis was calculated only utilizing the 5 prospective studies and consisted of 249 patients with an average of 3.2 months follow-up. In the short-term (2 weeks), there was a 15% difference favoring TFESI vs. ILESI for pain relief. There was no efficacy difference at one or 6 months. Combined pain improvements in all 5 prospective studies revealed < 20% difference between TFESI and ILESI (54.1% vs. 42.7%). There was slightly better functional improvement in ILESI groups (56.4%) vs. TFESI groups (49.4%) at 2 weeks. Combined data showed slight differences (TFESI 40.1% and ILESI 44.8%).

Limitations: The limitations of this systematic review include the relative paucity of comparative studies.

Conclusions: The findings show that both TFESI and ILESI are effective in reducing pain and improving functional scores in unilateral LSRP. In the treatment of pain, TFESI demonstrated non-clinically significant superiority to ILESI only at the 2-week follow-up. Based on 2 studies, ILESI demonstrated non-clinically significant superiority to TFESI in functional improvement.

Note: A published correction appears in Ann Intern Med. 2012 Jan 3;156(1 Pt 1):71.

Abstract
Diagnostic imaging is indicated for patients with low back pain only if they have severe progressive neurologic deficits or signs or symptoms that suggest a serious or specific underlying condition. In other patients, evidence indicates that routine imaging is not associated with clinically meaningful benefits but can lead to harms. Addressing inefficiencies in diagnostic testing could minimize potential harms to patients and have a large effect on use of resources by reducing both direct and downstream costs. In this area, more testing does not equate to better care. Implementing a selective approach to low back imaging, as suggested by the American College of Physicians and American Pain Society guideline on low back pain, would provide better care to patients, improve outcomes, and reduce costs.

Abstract
Objective: The discovery of neuroplastic phenomena such as central sensitization of nociception has challenged pain theory to evolve, to encompass unpredictable and unlikely chronic pain states, and to cope with the emerging complexity of the brain. Recently, the proposition that chronic pain is a disease in its own right has gained currency, based upon functional and structural changes in the brain constituting a distinctive pathology. Proponents have expanded the theory to identify "eudynia" ("good" pain) and "maldynia" ("bad" pain).

Methods: A critical examination of the proposition that chronic pain is a disease was conducted within the framework of evolution of pain medicine theory.

Results: Three dominant theories were identified: specificity theory (the "hard-wired" nervous system); neuroplasticity theory (the "soft-wired" nervous system); and pain-as-a-disease. The progression from specificity theory to neuroplasticity theory was based upon empirical evidence and conceptual clarity. The latter theory confronts the uncertainty and the unpredictability of pain, and offers explanations for conditions where ongoing noxious input is not discernible. However, not only does pain-as-a-disease elevate the neurophysiological mechanisms underlying the experience of chronic pain to the status of a disease, but also it conceives of pain as a "thing" that is itself capable of producing an effect. This reasoning is found to be faulty on two grounds: the confusion of pain as a symptom, a cause, and a pathology; and the fallacy that can arise when an interpretation is claimed to be a truth.

Conclusions: The proposition that chronic pain is a disease cannot be supported on clinical and pathological grounds, as well as in terms of ways of knowing. The promulgation of "good" and "bad" pain has the potential to obstruct necessary dialogue for advancing the science and treatment of pain. We suggest a way forward to resolve this impasse.

Abstract
Many clinical practice guidelines recommend similar approaches for the assessment and management of low back pain. Recommendations include use of a biopsychosocial framework to guide management with initial non-pharmacological treatment, including education that supports self-management and resumption of normal activities and exercise, and psychological programmes for those with persistent symptoms. Guidelines recommend prudent use of medication, imaging, and surgery. The recommendations are based on trials almost exclusively from high-income countries, focused mainly on treatments rather than on prevention, with limited data for cost-effectiveness. However, globally, gaps between evidence and practice exist, with limited use of recommended first-line treatments and inappropriately high use of imaging, rest, opioids, spinal injections, and surgery. Doing more of the same will not reduce back-related disability or its long-term consequences. The advances with the greatest potential are arguably those that align practice with the evidence, reduce the focus on spinal abnormalities, and ensure promotion of activity and function, including work participation. We have identified effective, promising, or emerging solutions that could offer new directions, but that need greater attention and further research to determine if they are appropriate for large-scale implementation. These potential solutions include focused strategies to implement best practice, the redesign of clinical pathways, integrated health and occupational interventions to reduce work disability, changes in compensation and disability claims policies, and public health and prevention strategies.

Abstract
Low back pain is a very common symptom. It occurs in high-income, middle-income, and low-income countries and all age groups from children to the elderly population. Globally, years lived with disability caused by low back pain increased by 54% between 1990 and 2015, mainly because of population increase and ageing, with the biggest increase seen in low-income and middle-income countries. Low back pain is now the leading cause of disability worldwide. For nearly all people with low back pain, it is not possible to identify a specific nociceptive cause. Only a small proportion of people have a well understood pathological cause-eg, a vertebral fracture, malignancy, or infection. People with physically demanding jobs, physical and mental comorbidities, smokers, and obese individuals are at greatest risk of reporting low back pain. Disabling low back pain is over-represented among people with low socioeconomic status. Most people with new episodes of low back pain recover quickly; however, recurrence is common and in a small proportion of people, low back pain becomes persistent and disabling. Initial high pain intensity, psychological distress, and accompanying pain at multiple body sites increases the risk of persistent disabling low back pain. Increasing evidence shows that central pain-modulating mechanisms and pain cognitions have important roles in the development of persistent disabling low back pain. Cost, health-care use, and disability from low back pain vary substantially between countries and are influenced by local culture and social systems, as well as by beliefs about cause and effect. Disability and costs attributed to low back pain are projected to increase in coming decades, in particular in low-income and middle-income countries, where health and other systems are often fragile and not equipped to cope with this growing burden. Intensified research efforts and global initiatives are clearly needed to address the burden of low back pain as a public health problem.

Abstract
Background: The identification of serious pathologies, such as spinal malignancy, is one of the primary purposes of the clinical assessment of patients with low-back pain (LBP). Clinical guidelines recommend awareness of "red flag" features from the patient's clinical history and physical examination to achieve this. However, there are limited empirical data on the diagnostic accuracy of these features and there remains very little information on how best to use them in clinical practice.

Objectives: To assess the diagnostic performance of clinical characteristics identified by taking a clinical history and conducting a physical examination ("red flags") to screen for spinal malignancy in patients presenting with LBP.

Search methods: We searched electronic databases for primary studies (MEDLINE, EMBASE, and CINAHL) and systematic reviews (PubMed and Medion) from the earliest date until 1 April 2012. Forward and backward citation searching of eligible articles was also performed.

Selection criteria: We considered studies if they compared the results of history taking and physical examination on patients with LBP with those of diagnostic imaging (magnetic resonance imaging, computed tomography, myelography).

Data collection and analysis: Two review authors independently assessed the quality of each included study with the QUality Assessment of Diagnostic Accuracy Studies (QUADAS) tool and extracted details on patient characteristics, study design, index tests, and reference standard. Diagnostic accuracy data were presented as sensitivities and specificities with 95% confidence intervals for all index tests.

Main results: We included eight cohort studies of which six were performed in primary care (total number of patients; n = 6622), one study was from an accident and emergency setting (n = 482), and one study was from a secondary care setting (n = 257). In the six primary care studies, the prevalence of spinal malignancy ranged from 0% to 0.66%. Overall, data from 20 index tests were extracted and presented, however only seven of these were evaluated by more than one study. Because of the limited number of studies and clinical heterogeneity, statistical pooling of diagnostic accuracy data was not performed.There was some evidence from individual studies that having a previous history of cancer meaningfully increases the probability of malignancy. Most "red flags" such as insidious onset, age > 50, and failure to improve after one month have high false positive rates.All of the tests were evaluated in isolation and no study presented data on a combination of positive tests to identify spinal malignancy.

Authors' conclusions: For most "red flags," there is insufficient evidence to provide recommendations regarding their diagnostic accuracy or usefulness for detecting spinal malignancy. The available evidence indicates that in patients with LBP, an indication of spinal malignancy should not be based on the results of one single "red flag" question. Further research to evaluate the performance of different combinations of tests is recommended.

Summary: Evidence-based medicine (EBM) has become a required element of clinical practice, but it is critical for the healthcare community to understand the ongoing controversy surrounding EBM. Seeking to address questions raised by critics, The Philosophy of Evidence-based Medicine challenges the over dependency of EBM on randomized controlled trials. This book also explores EBM methodology and its relationship with other approaches used in medicine.

Abstract
Objectives: To assess the quantity and quality of randomised, sham-controlled studies of surgery and invasive procedures and estimate the treatment-specific and non-specific effects of those procedures.

Design: Systematic review and meta-analysis.

Data sources: We searched PubMed, EMBASE, CINAHL, CENTRAL (Cochrane Library), PILOTS, PsycInfo, DoD Biomedical Research, clinicaltrials.gov, NLM catalog and NIH Grantee Publications Database from their inception through January 2015.

Study selection: We included randomised controlled trials of surgery and invasive procedures that penetrated the skin or an orifice and had a parallel sham procedure for comparison.

Data extraction and analysis: Three authors independently extracted data and assessed risk of bias. Studies reporting continuous outcomes were pooled and the standardised mean difference (SMD) with 95% CIs was calculated using a random effects model for difference between true and sham groups.

Results: 55 studies (3574 patients) were identified meeting inclusion criteria; 39 provided sufficient data for inclusion in the main analysis (2902 patients). The overall SMD of the continuous primary outcome between treatment/sham-control groups was 0.34 (95% CI 0.20 to 0.49; p<0.00001; I(2)=67%). The SMD for surgery versus sham surgery was non-significant for pain-related conditions (n=15, SMD=0.13, p=0.08), marginally significant for studies on weight loss (n=10, SMD=0.52, p=0.05) and significant for gastroesophageal reflux disorder (GERD) studies (n=5, SMD=0.65, p<0.001) and for other conditions (n=8, SMD=0.44, p=0.004). Mean improvement in sham groups relative to active treatment was larger in pain-related conditions (78%) and obesity (71%) than in GERD (57%) and other conditions (57%), and was smaller in classical-surgery trials (21%) than in endoscopic trials (73%) and those using percutaneous procedures (64%).

Conclusions: The non-specific effects of surgery and other invasive procedures are generally large. Particularly in the field of pain-related conditions, more evidence from randomised placebo-controlled trials is needed to avoid continuation of ineffective treatments.

Abstract
Purpose: The aim of this study is to establish standard MRI values for the cervical spinal canal, dural tube, and spinal cord, to evaluate age-related changes in healthy subjects, and to assess the prevalence of abnormal findings in asymptomatic subjects.

Methods: The sagittal diameter of the spinal canal and the sagittal diameter and cross-sectional area of the dural tube and spinal cord were measured on MRIs of 1,211 healthy volunteers. These included at least 100 men and 100 women in each decade of life between the third (20s) and eighth (70s). Abnormal findings such as spinal cord compression and signal changes in the spinal cord were recorded.

Results: The sagittal diameter of the spinal canal was 11.2 ± 1.4 mm [mean ± standard deviation (SD)]/11.1 ± 1.4 mm (male/female) at the mid-C5 vertebral level, and 9.5 ± 1.8/9.6 ± 1.6 mm at the C5/6 disc level. The cross-sectional area of the spinal cord was 78.1 ± 9.4/74.4 ± 9.4 mm² at the mid-C5 level and 70.6 ± 11.7/68.9 ± 11.3 mm² at the C5/6 disc level. Both the sagittal diameter and the axial area of the dural tube and spinal cord tended to decrease with increasing age. This tendency was more marked at the level of the intervertebral discs than at the level of the vertebral bodies, especially at the C5/6 intervertebral disc level. The spinal cord occupation rate in the dural tube at the C5 vertebral body level averaged 58.3 ± 7.0%. Spinal cord compression was observed in 64 cases (5.3%) and a T2 high-signal change was observed in 28 cases (2.3%).

Conclusions: Using MRI data of 1,211 asymptomatic subjects, the standard values for the cervical spinal canal, dural tube, and spinal cord for healthy members of each sex and each decade of life and the age-related changes in these parameters were established. The relatively high prevalence of abnormal MRI findings of the cervical spine in asymptomatic individuals emphasizes the dangers of predicating operative decisions on diagnostic tests without precisely correlating these findings with clinical signs and symptoms.

Manchikanti L, Kaye AD, Soin A, et al. Comprehensive Evidence-Based Guidelines for Facet Joint Interventions in the Management of Chronic Spinal Pain: American Society of Interventional Pain Physicians (ASIPP) Guidelines Facet Joint Interventions 2020 Guidelines. Pain Physician. 2020;23(3S):S1-S127.
Abstract
Background: Chronic axial spinal pain is one of the major causes of significant disability and health care costs, with facet joints as one of the proven causes of pain.

Objective: To provide evidence-based guidance in performing diagnostic and therapeutic facet joint interventions.

Methods: The methodology utilized included the development of objectives and key questions with utilization of trustworthy standards. The literature pertaining to all aspects of facet joint interventions, was reviewed, with a best evidence synthesis of available literature and utilizing grading for recommendations.Summary of Evidence and Recommendations:Non-interventional diagnosis: • The level of evidence is II in selecting patients for facet joint nerve blocks at least 3 months after onset and failure of conservative management, with strong strength of recommendation for physical examination and clinical assessment. • The level of evidence is IV for accurate diagnosis of facet joint pain with physical examination based on symptoms and signs, with weak strength of recommendation. Imaging: • The level of evidence is I with strong strength of recommendation, for mandatory fluoroscopic or computed tomography (CT) guidance for all facet joint interventions. • The level of evidence is III with weak strength of recommendation for single photon emission computed tomography (SPECT) . • The level of evidence is V with weak strength of recommendation for scintography, magnetic resonance imaging (MRI), and computed tomography (CT) .Interventional Diagnosis:Lumbar Spine: • The level of evidence is I to II with moderate to strong strength of recommendation for lumbar diagnostic facet joint nerve blocks. • Ten relevant diagnostic accuracy studies with 4 of 10 studies utilizing controlled comparative local anesthetics with concordant pain relief criterion standard of ≥80% were included. • The prevalence rates ranged from 27% to 40% with false-positive rates of 27% to 47%, with ≥80% pain relief.Cervical Spine: • The level of evidence is II with moderate strength of recommendation. • Ten relevant diagnostic accuracy studies, 9 of the 10 studies with either controlled comparative local anesthetic blocks or placebo controls with concordant pain relief with a criterion standard of ≥80% were included. • The prevalence and false-positive rates ranged from 29% to 60% and of 27% to 63%, with high variability. Thoracic Spine: • The level of evidence is II with moderate strength of recommendation. • Three relevant diagnostic accuracy studies, with controlled comparative local anesthetic blocks, with concordant pain relief, with a criterion standard of ≥80% were included. • The prevalence varied from 34% to 48%, whereas false-positive rates varied from 42% to 58%.Therapeutic Facet Joint Interventions: Lumbar Spine: • The level of evidence is II with moderate strength of recommendation for lumbar radiofrequency ablation with inclusion of 11 relevant randomized controlled trials (RCTs) with 2 negative studies and 4 studies with long-term improvement. • The level of evidence is II with moderate strength of recommendation for therapeutic lumbar facet joint nerve blocks with inclusion of 3 relevant randomized controlled trials, with long-term improvement. • The level of evidence is IV with weak strength of recommendation for lumbar facet joint intraarticular injections with inclusion of 9 relevant randomized controlled trials, with majority of them showing lack of effectiveness without the use of local anesthetic. Cervical Spine: • The level of evidence is II with moderate strength of recommendation for cervical radiofrequency ablation with inclusion of one randomized controlled trial with positive results and 2 observational studies with long-term improvement. • The level of evidence is II with moderate strength of recommendation for therapeutic cervical facet joint nerve blocks with inclusion of one relevant randomized controlled trial and 3 observational studies, with long-term improvement. • The level of evidence is V with weak strength of recommendation for cervical intraarticular facet joint injections with inclusion of 3 relevant randomized controlled trials, with 2 observational studies, the majority showing lack of effectiveness, whereas one study with 6-month follow-up, showed lack of long-term improvement. Thoracic Spine: • The level of evidence is III with weak to moderate strength of recommendation with emerging evidence for thoracic radiofrequency ablation with inclusion of one relevant randomized controlled trial and 3 observational studies. • The level of evidence is II with moderate strength of recommendation for thoracic therapeutic facet joint nerve blocks with inclusion of 2 randomized controlled trials and one observational study with long-term improvement. • The level of evidence is III with weak to moderate strength of recommendation for thoracic intraarticular facet joint injections with inclusion of one randomized controlled trial with 6 month follow-up, with emerging evidence. Antithrombotic Therapy: • Facet joint interventions are considered as moderate to low risk procedures; consequently, antithrombotic therapy may be continued based on overall general status. Sedation: • The level of evidence is II with moderate strength of recommendation to avoid opioid analgesics during the diagnosis with interventional techniques. • The level of evidence is II with moderate strength of recommendation that moderate sedation may be utilized for patient comfort and to control anxiety for therapeutic facet joint interventions.

Limitations: The limitations of these guidelines include a paucity of high-quality studies in the majority of aspects of diagnosis and therapy.

Conclusions: These facet joint intervention guidelines were prepared with a comprehensive review of the literature with methodologic quality assessment with determination of level of evidence and strength of recommendations.

Abstract
Study design: Cross-sectional study.

Objective: The purpose of this study was to determine the prevalence and distribution of abnormal findings on cervical spine magnetic resonance image (MRI).

Summary of background data: Neurological symptoms and abnormal findings on MR images are keys to diagnose the spinal diseases. To determine the significance of MRI abnormalities, we must take into account the (1) frequency and (2) spectrum of structural abnormalities, which may be asymptomatic. However, no large-scale study has documented abnormal findings of the cervical spine on MR image in asymptomatic subjects.

Methods: MR images were analyzed for the anteroposterior spinal cord diameter, disc bulging diameter, and axial cross-sectional area of the spinal cord in 1211 healthy volunteers. The age of healthy volunteers prospectively enrolled in this study ranged from 20 to 70 years, with approximately 100 individuals per decade, per sex. These data were used to determine the spectrum and degree of disc bulging, spinal cord compression (SCC), and increased signal intensity changes in the spinal cord.

Results: Most subjects presented with disc bulging (87.6%), which significantly increased with age in terms of frequency, severity, and number of levels. Even most subjects in their 20s had bulging discs, with 73.3% and 78.0% of males and females, respectively. In contrast, few asymptomatic subjects were diagnosed with SCC (5.3%) or increased signal intensity (2.3%). These numbers increased with age, particularly after age 50 years. SCC mainly involved 1 level (58%) or 2 levels (38%), and predominantly occurred at C5-C6 (41%) and C6-C7 (27%).

Conclusion: Disc bulging was frequently observed in asymptomatic subjects, even including those in their 20s. The number of patients with minor disc bulging increased from age 20 to 50 years. In contrast, the frequency of SCC and increased signal intensity increased after age 50 years, and this was accompanied by increased severity of disc bulging.

Level of evidence: 2.

Abstract
Originally the term "yellow flags" was used to describe psychosocial prognostic factors for the development of disability following the onset of musculoskeletal pain. The identification of yellow flags through early screening was expected to prompt the application of intervention guidelines to achieve secondary prevention. In recent conceptualizations of yellow flags, it has been suggested that their range of applicability should be confined primarily to psychological risk factors to differentiate them from other risk factors, such as social and environmental variables. This article addresses 2 specific questions that arise from this development: (1) Can yellow flags influence outcomes in people with acute or subacute low back pain? and (2) Can yellow flags be targeted in interventions to produce better outcomes? Consistent evidence has been found to support the role of various psychological factors in prognosis, although questions remain about which factors are the most important, both individually and in combination, and how they affect outcomes. Published early interventions have reported mixed results, but, overall, the evidence suggests that targeting yellow flags, particularly when they are at high levels, does seem to lead to more consistently positive results than either ignoring them or providing omnibus interventions to people regardless of psychological risk factors. Psychological risk factors for poor prognosis can be identified clinically and addressed within interventions, but questions remain in relation to issues such as timing, necessary skills, content of treatments, and context. In addition, there is still a need to elucidate mechanisms of change and better integrate this understanding into the broader context of secondary prevention of chronic pain and disability.

Abstract
Although self-reported measures play a central role in the assessment of pain and its treatment, it has long been recognized that interpretation of these measures is severely limited by the absence of normative data. Despite that, relatively few of the measures used in pain clinics or research studies have normative data for reference. Using a pain centre sample (n=6124), this paper describes the development of a normative dataset on a number of commonly used pain-related measures. The measures cover many of the key dimensions in pain assessment, including pain severity/quality, disability (physical functioning), and mood (emotional functioning). Measures of different cognitive and coping constructs are also included. Mean scores are reported for each measure according to age group, gender, pain site, as well as percentiles for different scores for patients with chronic low back pain. The potential uses for datasets of this type include the assessment and evaluation of individual cases, as well as the interpretation of published clinical trials. It is also argued that future systematic reviews of pain treatments should include consideration of such patient characteristics as pain levels, disability and mood in the studies reviewed rather than pain site and chronicity alone.

Abstract
This article describes a proposal for the new diagnosis of chronic primary pain (CPP) in ICD-11. Chronic primary pain is chosen when pain has persisted for more than 3 months and is associated with significant emotional distress and/or functional disability, and the pain is not better accounted for by another condition. As with all pain, the article assumes a biopsychosocial framework for understanding CPP, which means all subtypes of the diagnosis are considered to be multifactorial in nature, with biological, psychological, and social factors contributing to each. Unlike the perspectives found in DSM-5 and ICD-10, the diagnosis of CPP is considered to be appropriate independently of identified biological or psychological contributors, unless another diagnosis would better account for the presenting symptoms. Such other diagnoses are called "chronic secondary pain" where pain may at least initially be conceived as a symptom secondary to an underlying disease. The goal here is to create a classification that is useful in both primary care and specialized pain management settings for the development of individualized management plans, and to assist both clinicians and researchers by providing a more accurate description of each diagnostic category.

Abstract
Low back pain (LBP) is the most common pain syndrome, and is an enormous burden and cost generator for society. Lumbar facet joints (FJ) constitute a common source of pain, accounting for 15-45% of LBP. Facet joint degenerative osteoarthritis is the most frequent form of facet joint pain. History and physical examination may suggest but not confirm facet joint syndrome. Although imaging (radiographs, MRI, CT, SPECT) for back pain syndrome is very commonly performed, there are no effective correlations between clinical symptoms and degenerative spinal changes. Diagnostic positive facet joint block can indicate facet joints as the source of chronic spinal pain. These patients may benefit from specific interventions to eliminate facet joint pain such as neurolysis, by radiofrequency or cryoablation. The purpose of this review is to describe the anatomy, epidemiology, clinical presentation, and radiologic findings of facet joint syndrome. Specific interventional facet joint management will also be described in detail. TEACHING POINTS: • Lumbar facet joints constitute a common source of pain accounting of 15-45%. • Facet arthrosis is the most frequent form of facet pathology. • There are no effective correlations between clinical symptoms, physical examination and degenerative spinal changes. • Diagnostic positive facet joint block can indicate facet joints as the source of pain. • After selection processing, patients may benefit from facet joint neurolysis, notably by radiofrequency or cryoablation.

Abstract
Chronic musculoskeletal pain is defined as chronic pain arising from musculoskeletal structures such as bones or joints. Although comprising the most prevalent set of chronic pain conditions, it was not represented appropriately in the 10th edition of the International Classification of Diseases (ICD-10), which was organized mainly according to anatomical sites, was strongly focused on musculoskeletal disease or local damage, and did not consider the underlying mechanisms of pain. The new ICD-11 classification introduces the concept of chronic primary and secondary musculoskeletal pain, and integrates the biomedical axis with the psychological and social axes that comprise the complex experience of chronic musculoskeletal pain. Chronic primary musculoskeletal pain is a condition in its own right, not better accounted for by a specific classified disease. Chronic secondary musculoskeletal pain is a symptom that arises from an underlying disease classified elsewhere. Such secondary musculoskeletal pain originates in persistent nociception in musculoskeletal structures from local or systemic etiologies, or it may be related to deep somatic lesions. It can be caused by inflammation, by structural changes, or by biomechanical consequences of diseases of the nervous system. It is intended that this new classification will facilitate access to patient-centered multimodal pain management and promote research through more accurate epidemiological analyses.

Abstract
Study design: A systematic review and meta-analysis of randomized controlled trials.

Objective: To assess treatment effects (benefits and harms) of radiofrequency denervation for patients with facet joint-related chronic low back pain.

Summary of background data: There is no consensus regarding the treatment efficacy of facet joint radiofrequency denervation (FJRD) and how it compares with nerve blockades and joint infiltration with anesthetics and/or corticosteroids.

Methods: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and LILACS for randomized controlled trials that compared FJRD with blockades, infiltrations, or placebo. Primary outcomes were pain, functional status, and quality of life. Secondary outcomes were cost-effectiveness and complications.

Results: Fifteen studies were selected and 9 were eligible. Overall quality of evidence was rated low to moderate. The evidence favored FJRD regarding pain control. There was no sufficient evidence for cost-effectiveness and complications.

Conclusion: The available evidence reviewed in this study should be interpreted with caution. The data indicate that FJRD is more effective than placebo in pain control and functional improvement and is also possibly more effective than steroid injections in pain control. Complications and adverse effects were not sufficiently reported to allow comparisons, and there was no evidence for cost-effectiveness. High-quality randomized controlled trials addressing pain, function, quality of life, complications, and cost-effectiveness are urgently needed.

Level of evidence: 1.

Systematic reviews are carried out by a large number of staff and students at King's College London and King's Health Partners across the disciplines. This guide aims to assist you in understanding more about how to effectively and systematically search for literature to include in your systematic review. The main focus is on searching for content to include in systematic reviews carried out in health and clinical and life sciences, but some specific links and guidance are also available for searching for systematic reviews of social interventions and other qualitative research areas in health and the social sciences.

The inherent subjectivity of pain presents a fundamental impediment to increased understanding of its mechanisms and control. The language used by any two individuals attempting to describe a similar injury and their pain experience often varies markedly. Similarly, clinicians and clinical investigators commonly use multiple terms that at times have idiosyncratic meanings. Needless to say, appropriate communication requires a common language and a classification system that is used in a consistent fashion. Thus, we have two primary goals in this chapter: (1) to provide definitions for many commonly used terms in the pain literature, in an effort to bring about consistency and thereby improve communication, and (2) to describe and discuss different classification systems or taxonomies that have been used or proposed, in an attempt to improve communication and bring consistency to research and treatment of patients reporting pain.