Psychopathology predicts the outcome of medial branch blocks with corticosteroid for chronic axial low back or cervical pain: a prospective cohort study

Predictors of Outcomes After Lumbar Intra-Articular Facet Joint Injections and Medial Branch Blocks: A Scoping Review

STUDY DESIGN

A scoping review.

OBJECTIVE

We aimed to identify and describe the factors associated with the patient-reported response after lumbar intra-articular facet joint (FJ) injections or medial branch blocks (MBBs).

SUMMARY OF BACKGROUND DATA

FJ osteoarthritis is among the most common causes of chronic low back pain. Management often includes FJ intra-articular injection and MBBs (which may be followed by radiofrequency ablation of the nerves innervating these joints). However, the success of these approaches is variable, prompting interest in identifying patient characteristics (imaging features, clinical signs, and among others) associated with response to these types of facet injections.

MATERIALS AND METHODS

We performed a literature search on factors associated with patient-reported outcomes after lumbar FJ intra-articular injections or MBBs for patients with low back pain published in English or Spanish between 2000 and 2023. We excluded duplicate papers that did not describe factors associated with outcomes or those describing other interventions. We collected data on the association of these factors with patient-reported outcomes.

RESULTS

Thirty-seven studies met the inclusion criteria and were analyzed. These studies evaluated factors, such as age, depression, and single photon emission computed tomography (SPECT), and among variables. Age and imaging findings of facet arthropathy were the most frequently described factors. Imaging findings of FJ arthropathy and positive SPECT were often associated with positive results after intra-articular FJ injections or MBBs. In contrast, younger age and smoking were frequently associated with less favorable clinical outcomes.

CONCLUSION

Numerous factors were considered in the 37 studies included in this review. Imaging findings of facet arthropathy, duration of pain, and positive SPECT were consistently associated with favorable results after facet interventions.

Covariate Adjustment in Chronic Pain Trials: An Oft-Missed Opportunity

Self-reported pain intensity, frequently used as an outcome in randomized clinical trials (RCTs) of chronic pain, is often highly variable and could be associated with multiple baseline factors. Thus, the assay sensitivity of pain trials (ie, the ability of the trial to detect a true treatment effect) could be improved by including prespecified baseline factors in the primary statistical model. The objective of this focus article was to characterize the baseline factors included in statistical analyses of chronic pain RCTs. Seventy-three RCTs published between 2016 and 2021 that investigated interventions for chronic pain were included. The majority of trials identified a single primary analysis (72.6%; n = 53). Of these, 60.4% (n = 32) included one or more covariates in the primary statistical model, most commonly baseline value of the primary outcome, study site, sex, and age. Only one of the trials reported information regarding associations between covariates and outcomes (ie, information that could inform prioritization of covariates for prespecification in future analyses). These findings demonstrate inconsistent use of covariates in the statistical models in chronic pain clinical trials. Prespecified adjustments for baseline covariates that could increase precision and assay sensitivity should be considered in future clinical trials of chronic pain treatments. PERSPECTIVE: This review demonstrates inconsistent inclusion and potential underutilization of covariate adjustment in analyses of chronic pain RCTs. This article highlights areas for possible improvement in design and reporting related to covariate adjustment to improve efficiency in future RCTs.

Back Pain Consortium (BACPAC): Protocol and Pilot Study Results for a Randomized Comparative-Effectiveness Trial of Antidepressants, Fear Avoidance Rehabilitation, or the Combination for Chronic Low Back Pain and Comorbid High Negative Affect

OBJECTIVE

Patients with chronic low back pain (CLBP) and comorbid depression or anxiety disorders are highly prevalent. Negative affect (NA) refers to a combination of negative thoughts, emotions, and behaviors. Patients with CLBP with high NA have greater pain, worse treatment outcomes, and greater prescription opioid misuse. We present the protocol for SYNNAPTIC (SYNergizing Negative Affect & Pain Treatment In Chronic pain).

DESIGN

A randomized comparative-effectiveness study of antidepressants, fear-avoidance rehabilitation, or their combination in 300 patients with CLBP with high NA. In the antidepressant- or rehabilitation-only arms, SYNNAPTIC includes an adaptive design of re-randomization after 4 months for nonresponders.

SETTING

A multisite trial conducted in routine pain clinical treatment settings: pain clinics and physical and occupational therapy treatment centers.

METHODS

Inclusion criteria include CLBP with elevated depression and anxiety symptoms. Antidepressant and rehabilitation treatments follow validated and effective protocols for musculoskeletal pain in patients with high NA. Power and sample size are based on superior outcomes of combination therapy with these same treatments in a 71-subject 4-arm pilot randomized controlled trial.

CONCLUSIONS

SYNNAPTIC addresses the lack of evidence-based protocols for the treatment of the vulnerable subgroup of patients with CLBP and high NA. We hypothesize that combination therapy of antidepressants plus fear-avoidance rehabilitation will be more effective than each treatment alone.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT04747314.

Exploring the Use of Facet Joint Injections Through Instagram

PURPOSE

 Facet joint injection (FJI) is a minimally invasive procedure used to relieve pain and inflammation in the facet joints of the spine. In light of the growing presence of social media, it is essential to comprehend its effects on the healthcare industry. Little is known about how FJI is discussed on Instagram. The purpose of this study was to investigate the characteristics and production sources of FJI-related posts on Instagram.

METHODS AND MATERIALS

This study provides a descriptive analysis of Instagram posts with the keywords #facetjointinjection, #facetjointinjections, #facetinjection, #facetinjections, #facetblock, and #facetblocks on March 1, 2023. The results were categorized by source into four groups; posts created by healthcare professionals (surgeon/non-surgeon), medical organizations, patients, or not otherwise specified. The content was categorized by type (educational and patient/physician experience) and user influence (number of followers and posts).

RESULTS

The search resulted in 2718 posts. Most post uploaders were mainly physicians (43.1%, n = 275). The distribution of remaining Instagram users with FJIs posts was as follows: 27.1% (n=173) patients, 16.3% (n=104) medical organizations, and 13.4% (n=86) not otherwise specified. Among the posts, 1136 (41.7 %) were from accounts created by patients, 1015 (37.3%) by physicians, 441 (16.2%) by medical organizations, and 126 (4.6%) were unspecified. The analysis showed a significant difference in the distribution of posts among patients and physicians, as well as patients and other unspecified groups (p<0.05). The reported side effects were as follows: pain around the injection site (36%), swelling (17%), weight gain (15%), and anxiety (32%).

CONCLUSIONS

This study demonstrates that physicians are widely present on social media. However, when searching for posts about facet joint interventions, posts written by patients are more likely to be seen by the public. The results of this article emphasize the impact physicians have on online platforms and the need to raise FJI awareness on Instagram. Due to a lack of information and their anxiety about the unknown, patients have voiced hesitation about undergoing FJIs. To address this issue, it is the responsibility of physicians to enhance the accessibility of accurate information for patients in order to alleviate their anxiety. Additionally, reputable pain medicine societies and qualified specialists should upload credible posts on facet joint interventions that include accurate information, high-quality images and videos, and proper scientific commentary, with the aim of enhancing the quality of online health information.

Optimizing and Accelerating the Development of Precision Pain Treatments for Chronic Pain: IMMPACT Review and Recommendations

Large variability in the individual response to even the most-efficacious pain treatments is observed clinically, which has led to calls for a more personalized, tailored approach to treating patients with pain (ie, "precision pain medicine"). Precision pain medicine, currently an aspirational goal, would consist of empirically based algorithms that determine the optimal treatments, or treatment combinations, for specific patients (ie, targeting the right treatment, in the right dose, to the right patient, at the right time). Answering this question of "what works for whom" will certainly improve the clinical care of patients with pain. It may also support the success of novel drug development in pain, making it easier to identify novel treatments that work for certain patients and more accurately identify the magnitude of the treatment effect for those subgroups. Significant preliminary work has been done in this area, and analgesic trials are beginning to utilize precision pain medicine approaches such as stratified allocation on the basis of prespecified patient phenotypes using assessment methodologies such as quantitative sensory testing. Current major challenges within the field include: 1) identifying optimal measurement approaches to assessing patient characteristics that are most robustly and consistently predictive of inter-patient variation in specific analgesic treatment outcomes, 2) designing clinical trials that can identify treatment-by-phenotype interactions, and 3) selecting the most promising therapeutics to be tested in this way. This review surveys the current state of precision pain medicine, with a focus on drug treatments (which have been most-studied in a precision pain medicine context). It further presents a set of evidence-based recommendations for accelerating the application of precision pain methods in chronic pain research. PERSPECTIVE: Given the considerable variability in treatment outcomes for chronic pain, progress in precision pain treatment is critical for the field. An array of phenotypes and mechanisms contribute to chronic pain; this review summarizes current knowledge regarding which treatments are most effective for patients with specific biopsychosocial characteristics.

Comparative Effectiveness of Embedded Mental Health Services in Pain Management Clinics vs Standard Care

OBJECTIVE

Embedded behavioral medicine services are a common component of multidisciplinary chronic pain treatment programs. However, few studies have studied whether these services are associated with improved treatment outcomes.

METHODS

Using a retrospective, matched, two-cohort study design, we examined patient-reported outcomes (PROs), including Patient-Reported Outcomes Measurement Information System pain, mental health, and physical function measures, collected at every clinic visit in every patient. Changes from baseline through 12 months were compared in those receiving embedded Behavioral Medicine in addition to usual care to a Standard Care group seen in the same pain practice and weighted via propensity scoring.

RESULTS

At baseline, Behavioral Medicine patients had worse scores on most pain, mental health, and physical health measures and were more likely to be female, a member of a racial minority, and have lower socioeconomic status. Regardless of having a worse clinical pain syndrome at baseline, at follow-up both Behavioral Medicine (N = 451) and Standard Care patients (N = 8,383) showed significant and comparable improvements in pain intensity, physical function, depression, and sleep disturbance. Behavioral Medicine patients showed significantly greater improvements in their global impressions of change than the Standard Care patients.

CONCLUSIONS

Despite worse pain and physical and psychological functioning at baseline, Behavioral Medicine patients showed improvements comparable to patients not receiving these services. Further, Behavioral Medicine patients report higher global impressions of change, indicating that embedded mental health services appear to have the additive value of amplifying the benefits of multimodal pain care.

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

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

Therapeutic Facet Joint Interventions in the Lumbar Spine: An Economic Value Perspective

OBJECTIVE

In this narrative review, the current literature on therapeutic interventions for low back pain of facet joint etiology is assessed from an economic value perspective.

SUMMARY OF BACKGROUND DATA

The efficacy and economics of facet joint interventions in the treatment of lumbar back pain is a controversial topic. Trends show that facet joint interventions are becoming increasingly used, perhaps as physicians become more averse to treating chronic low back pain with opioids. With the emphasis on value-based spine care and changing reimbursement models, the perspective of rigorously evaluating the outcomes these interventions provide and the costs they incur is particularly relevant.

DISCUSSION

Although the evidence is noted to be limited, most systematic reviews fail to demonstrate the therapeutic utility of intra-articular facet joint injections in low back pain because of high study heterogeneity. A few good quality studies and systematic reviews describe moderate evidence for the utilization of therapeutic medial branch blocks and radiofrequency neurotomies in alleviating facet joint pain.

CONCLUSION

Consequently, there is a need for high-quality cost-effectiveness studies for facet joint interventions so that evidence-based and economically viable solutions can be used to optimize patient care at a societally affordable price.

Cognitive Biases Toward Pain: Implications for a Neurocognitive Processing Perspective in Chronic Pain and its Interaction With Depression

OBJECTIVES

Information-processing biases such as attentional, interpretation, and memory biases are supposed to play a role in the exacerbation and maintenance of chronic pain. Current research in the area of cognitive biases shows that all these biases seem to have an influence on attention to, interpretation of, and recall of pain and can lead to maladaptive strategies and the exacerbation of pain.

METHODS

We conducted a narrative literature review, considering evidence extracted from various databases including PubMed, MEDLINE, Science Direct, and ProQuest. Search terms included cognitive biases, neurocognitive processing, chronic pain, and depression.

RESULTS

The literature on attentional, interpretative, and memory biases in experimental and chronic pain, as well as their neuronal underpinnings, suggests that the depression of chronic pain patients may differ from the depression of patients without pain. Depressed pain patients show a recall bias for illness-related and health-related stimuli, whereas depressed patients without pain show a bias for depression-related stimuli. In addition, research has shown that catastrophizing, helplessness/hopelessness, and thought suppression as psychological responses to pain are mediators of the relationship between chronic pain and depression.

CONCLUSIONS

Current research supports the importance of individual diagnosis of chronic pain patients and their response patterns of pain, psychological processing, and information processing. This leads to the conclusion that depressed pain patients need other clinical interventions when compared with depressed patients without pain. Previous research showed that a combination of a cognitive-behavioral therapy with mindfulness meditation seems to be a promising approach.

Predictors of Pain Recurrence After Lumbar Facet Joint Injections

Introduction

Facet joint injections (FJIs) of anesthetic and corticosteroids are useful for the diagnosis and treatment of low back pain (LBP). In the current study, we evaluated the efficacy of FJI on LBP treatment and the predictive variables of pain recurrence after FJI.

Methods

We included and followed prospectively forty-three consecutive patients with chronic LBP treated with FJI. Clinical assessments were carried out at a baseline 1 week before FJIs and after a 6-month follow-up visit using the visual analog scale (VAS) for pain, Oswestry Disability Index (ODI) for disability-specific measure and MacNab criteria for global effectiveness, and compared through analysis using paired-samples “t” tests. Multiple cox-regression analysis was used to identify the presurgical variables independently associated with pain recurrence anytime during the follow-up. In addition to the demographic, clinical, and surgical data, we also analyzed psychometric scales: Pain Catastrophizing Scale (PCS), Beck Anxiety Inventory (BAI), and Beck Depression Inventory (BDI).

Results

After a 6-month follow-up, thirty-two patients (74.4%) showed a clinically significant reduction of pain and twenty-seven (62.8%) reported a clinically significant improvement of disability. Presurgical catastrophizing (PCS score ≥ 5, adjusted HR 4.4, CI 95% 1.7–11.3, p = 0.002) and smoking (Adjusted HR 12.5, CI 95% 1.1–138.9, p = 0.04) remains associated with pain recurrence.

Conclusion

FJI reduces LBP and disability of patients with unresponsive LBP. Pain-related cognitive and behavioral factors determined by pain catastrophizing and smoking were independently associated with pain recurrence after lumbar FJI. The results support the need of a multidisciplinary approach for presurgical evaluation of patients with chronic pain.

Prognostic factors in low back pain individuals undergoing steroid and anaesthetic intra-articular facet joint infiltration: a protocol for a prospective, longitudinal, cohort study

INTRODUCTION

Lumbar pain of facet origin is a common problem worldwide. For those patients not responding to traditional treatment, one approach may be intra-articular infiltration of corticoid and anaesthetic. However, despite the increasing demand for this procedure, no consensus exists regarding its therapeutic value. The selection of eligible participants may be a determining factor since only those with an inflammatory process will benefit from the use of corticosteroids. This study aims to identify differences in disability, pain and quality of life scores in individuals with and without facet joint inflammation who were diagnosed using MRI.

METHOD AND ANALYSIS

This prospective cohort will include individuals older than 18 years with a clinical diagnosis of facet syndrome who underwent intra-articular infiltration. Changes in scores of pain, disability and quality of life questionnaires at 1, 3, 6 and 12 months of follow-up compared with baseline will be analysed. An MRI examination performed before infiltration will help to distinguish between exposed (with inflammation) and non-exposed (non-inflammation) groups with facet syndrome. The primary outcome will be the disability questionnaire (Roland Morris), and the secondary outcomes will be the score questionnaires for pain (Visual Analogue Scale), quality of life (EuroQol Quality of Life Questionnaire) and disability (Oswestry).

ETHICS AND DISSEMINATION

The Internal Review Board approved this study, which started only after the approval number (5291417.0.0000.0071) was received. All recruited participants will receive a verbal explanation about the purpose of the study, and their decision to participate will be free and voluntary. All participants enrolled in the study will provide a signed informed consent form including confidentiality terms. The results obtained in this study will be presented at national and international conferences and published in peer-reviewed scientific journals to disseminate the knowledge.

TRIALS REGISTRATION NUMBER

NCT03304730; Pre-results.

Predictors of Response to a Medial Branch Block: MRI Analysis of the Lumbar Spine

The aim of this study was to determine the association between radiologic spinal pathology and the response to medial branches block (MBB). This retrospective observational study compared 165 patients. A successful response was defined as ≥30% or a 2-point reduction in the numeric rating scale (NRS) compared with the baseline at the 1-month follow-up. The facet angle, facet angle difference, facet joint degeneration, disc height and spondylolisthesis grade were analyzed from an MRI at the L3 to S1 levels. Univariate and multivariate logistic regression analyses were used to evaluate independent factors associated with a successful response of MBB. In the univariate analysis, the disc height at L5-S1 and facet angle difference at L3-4 were lower in the positive responders (p = 0.022 and p = 0.087, respectively). In the multivariate analysis, the facet angle difference at L3-4 and disc height at L5-S1 were independent factors associated with a successful response (odds ratio = 0.948; p = 0.038 and odds ratio = 0.864; p = 0.038, respectively). In patients with a degenerative disc at L5-S1, MBB can lead to a good response for at least one month. In patients with facet tropism at L3-4 level, the response to MBB after one month is likely to be poor.

Analgesic effects of repetitive transcranial magnetic stimulation on modified 2010 criteria-diagnosed fibromyalgia: Pilot study

AIM

Fibromyalgia is often comorbid with depression, and less than half those patients achieve satisfactory improvement after adequate pharmacological intervention. The investigation of repetitive transcranial magnetic stimulation (rTMS) at left dorsolateral prefrontal cortex for modified-2010 American College of Rheumatology (ACR) fibromyalgia and major depressive disorder (MDD) is still in its infancy.

METHODS

In this double-blind, randomized, sham-control study, subjects diagnosed with ACR-2010 fibromyalgia and DSM-IV-TR MDD were recruited and received either active or sham interventions for 2 weeks. Hamilton Depression Rating Scale (HDRS) and the 10-cm visual analogue pain scale were evaluated at baseline, week 1, and week 2. Multivariable generalized estimating equations analysis was performed for the association between depression and pain scores at each checkpoint.

RESULTS

Twenty subjects were recruited. There was a significant difference over the 2 weeks between the rTMS and sham stimulation groups (P = 0.029), but subgroup analyses were further performed due to significant interaction of group and HDRS on pain outcomes (P = 0.020). The active group had significant improvement in pain at week 2 compared with week 1 (P = 0.021), but the control group did not have any improvement in pain (P = 0.585). Of the mild-moderate depression patients, the pain score in the active group was significantly lower than in the sham group at week 1 (P = 0.001) and at week 2 (P < 0.001). For the severe depression group, there was significantly lower pain over the 2 weeks in the active group (P = 0.045) but the sham group had significantly relapsing pain at week 2 (P < 0.001).

CONCLUSION

Left prefrontal rTMS has an analgesic effect in modified-ACR 2010-defined fibromyalgia and MDD patients. Further investigation is required, however, in order to determine how to regulate the different rTMS treatment protocols according to individual baseline depression severity in patients with MDD and fibromyalgia.

The Association between Patient Characteristics and Opioid Treatment Response in Neuropathic and Nociceptive Pain due to Cancer

BACKGROUND

Cancer pain remains a difficult problem, for which opioids are often necessary. At present it is difficult to predict the effectiveness of opioid therapy.

OBJECTIVES

We aim to assess the association between patient characteristics and opioid treatment response in cancer patients, and develop a model to predict probability of response.

SUBJECTS

We used data from two previously published randomized clinical trials, in which patients with head and neck cancer were treated with fentanyl or methadone (total N = 134).

MEASUREMENTS

Treatment success was defined as ≥50% pain reduction at one and five weeks. We analyzed patient characteristics (age, sex, depression, and anxiety), treatment characteristics (having had chemotherapy, radiotherapy, surgery, methadone, or fentanyl) and pain characteristics (neuropathic and nociceptive).

DESIGN

Based on univariable and multivariable regression analyses determinants of therapy success were assessed. Based on these analyses a prediction model was developed.

RESULTS

Our analyses show that one-week therapy success was associated with methadone (odds ratio [OR] = 5.21), duration of pain in months (OR = 1.12), neuropathic pain (OR = 3.36), and age of the patient in years (OR = 0.95). Inclusion of these four characteristics into our prediction model resulted in an area under the curve of 81.6%.

CONCLUSIONS

Careful analyses of patient attributes, treatment, and pain type of patients with head and neck cancer resulted in a prediction model that allowed to predict short-term pain relief and the opioid treatment response in neuropathic and nociceptive pain owing to cancer.

Facet joint injections for people with persistent non-specific low back pain (Facet Injection Study): a feasibility study for a randomised controlled trial

BACKGROUND

The National Institute for Health and Care Excellence (NICE) 2009 guidelines for persistent low back pain (LBP) do not recommend the injection of therapeutic substances into the back as a treatment for LBP because of the absence of evidence for their effectiveness. This feasibility study aimed to provide a stable platform that could be used to evaluate a randomised controlled trial (RCT) on the clinical effectiveness and cost-effectiveness of intra-articular facet joint injections (FJIs) when added to normal care.

OBJECTIVES

To explore the feasibility of running a RCT to test the hypothesis that, for people with suspected facet joint back pain, adding the option of intra-articular FJIs (local anaesthetic and corticosteroids) to best usual non-invasive care is clinically effective and cost-effective.

DESIGN

The trial was a mixed design. The RCT pilot protocol development involved literature reviews and a consensus conference followed by a randomised pilot study with an embedded mixed-methods process evaluation.

SETTING

Five NHS acute trusts in England.

PARTICIPANTS

Participants were patients aged ≥ 18 years with moderately troublesome LBP present (> 6 months), who had failed previous conservative treatment and who had suspected facet joint pain. The study aimed to recruit 150 participants (approximately 30 per site). Participants were randomised sequentially by a remote service to FJIs combined with 'best usual care' (BUC) or BUC alone.

INTERVENTIONS

All participants were to receive six sessions of a bespoke BUC rehabilitation package. Those randomised into the intervention arm were, in addition, given FJIs with local anaesthetic and steroids (at up to six injection sites). Randomisation occurred at the end of the first BUC session.

MAIN OUTCOME MEASURES

Process and clinical outcomes. Clinical outcomes included a measurement of level of pain on a scale from 0 to 10, which was collected daily and then weekly via text messaging (or through a written diary). Questionnaire follow-up was at 3 months.

RESULTS

Fifty-two stakeholders attended the consensus meeting. Agreement informed several statistical questions and three design considerations: diagnosis, the process of FJI and the BUC package and informing the design for the randomised pilot study. Recruitment started on 26 June 2015 and was terminated by the funder (as a result of poor recruitment) on 11 December 2015. In total, 26 participants were randomised. Process data illuminate some of the reasons for recruitment problems but also show that trial processes after enrolment ran smoothly. No between-group analysis was carried out. All pain-related outcomes show the expected improvement between baseline and follow-up. The mean total cost of the overall treatment package (injection £419.22 and BUC £264.00) was estimated at £683.22 per participant. This is similar to a NHS tariff cost for a course of FJIs of £686.84.

LIMITATIONS

Poor recruitment was a limiting factor.

CONCLUSIONS

This feasibility study achieved consensus on the main challenges in a trial of FJIs for people with persistent non-specific low back pain.

FUTURE WORK

Further work is needed to test recruitment from alternative clinical situations.

TRIAL REGISTRATION

EudraCT 2014-000682-50 and Current Controlled Trials ISRCTN93184143.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 30. See the NIHR Journals Library website for further project information.

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

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

The Role of Psychosocial Processes in the Development and Maintenance of Chronic Pain

The recently proposed Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION)-American Pain Society (APS) Pain Taxonomy (AAPT) provides an evidence-based, multidimensional, chronic pain classification system. Psychosocial factors play a crucial role within several dimensions of the taxonomy. In this article, we discuss the evaluation of psychosocial factors that influence the diagnosis and trajectory of chronic pain disorders. We review studies in individuals with a variety of persistent pain conditions, and describe evidence that psychosocial variables play key roles in conferring risk for the development of pain, in shaping long-term pain-related adjustment, and in modulating pain treatment outcomes. We consider "general" psychosocial variables such as negative affect, childhood trauma, and social support, as well as "pain-specific" psychosocial variables that include pain-related catastrophizing, self-efficacy for managing pain, and pain-related coping. Collectively, the complexity and profound variability in chronic pain highlights the need to better understand the multidimensional array of interacting forces that determine the trajectory of chronic pain conditions.

PERSPECTIVE

The AAPT is an evidence-based chronic pain classification system in which psychosocial concepts and processes are essential in understanding the development of chronic pain and its effects. In this article we review psychosocial processes that influence the onset, exacerbation, and maintenance of chronic pain disorders.

Self-reports of medication side effects and pain-related activity interference in patients with chronic pain: a longitudinal cohort study

The primary purpose of this study was to examine the association between self-reports of medication side effects and pain-related activity interference in patients with chronic pain. The potential moderators of the association between reports of side effects and pain-related activity interference were also examined. A total of 111 patients with chronic musculoskeletal pain were asked to provide, once a month for a period of 6 months, self-reports of medication use and the presence of any perceived side effects (eg, nausea, dizziness, headaches) associated with their medications. At each of these time points, patients were also asked to provide self-reports of pain intensity, negative affect, and pain-related activity interference. Multilevel modeling analyses revealed that month-to-month increases in perceived medication side effects were associated with heightened pain-related activity interference (P < 0.05). Importantly, multilevel models revealed that perceived medication side effects were associated with heightened pain-related activity interference even after controlling for the influence of patient demographics, pain intensity, and negative affect. This study provides preliminary evidence that reports of medication side effects are associated with heightened pain-related activity interference in patients with chronic pain beyond the influence of other pain-relevant variables. The implications of our findings for clinical practice and the management of patients with chronic pain conditions are discussed.

Psychiatric Comorbidity Is Associated Prospectively with Diminished Opioid Analgesia and Increased Opioid Misuse in Patients with Chronic Low Back Pain

BACKGROUND

Opioids are frequently prescribed for chronic low back pain (CLBP), but there are little prospective data on which patient subgroups may benefit. Psychiatric comorbidity, such as high levels of depression and anxiety symptoms (termed comorbid negative affect [NA]), is a common presentation and may predict diminished opioid analgesia and/or increased opioid misuse.

METHODS

The authors conducted a 6½-month prospective cohort study of oral opioid therapy, with an active drug/placebo run-in period, in 81 CLBP patients with low, moderate, and high levels of NA. Treatment included an opioid titration phase with a prescribing physician blinded to NA group assignment and a 4-month continuation phase, during which subjects recorded daily pain levels using an electronic diary. The primary outcome was the percent improvement in average daily pain, summarized weekly.

RESULTS

There was an overall 25% dropout rate. Despite the high NA group being prescribed a higher average daily dose of morphine equivalents, linear mixed model analysis revealed that the 24 study completers in each of the high NA and low NA groups had an average 21 versus 39% improvement in pain, respectively (P < 0.01). The high NA group also had a significantly greater rate of opioid misuse (39 vs. 8%, P < 0.05) and significantly more and intense opioid side effects (P < 0.01).

CONCLUSIONS

These results indicate that the benefit and risk considerations in CLBP patients with high NA versus low NA are distinctly different. Thus, NA is an important phenotypic variable to characterize at baseline, before deciding whether to prescribe opioids for CLBP.

Assessment and management of chronic pain in patients with depression and anxiety

This article will review the role of the pharmacist in the management of chronic pain in patients with comorbid mood disorders.

The association between negative affect and prescription opioid misuse in patients with chronic pain: the mediating role of opioid craving

Over the past decade, considerable research has accumulated showing that chronic pain patients experiencing high levels of negative affect (NA) are at increased risk for prescription opioid misuse. The primary objective of the present study was to examine the factors that underlie the association between NA and prescription opioid misuse among patients with chronic pain. In this study, 82 patients with chronic musculoskeletal pain being prescribed opioid medication completed the Current Opioid Misuse Measure, a well-validated self-report questionnaire designed to assess prescription opioid misuse. Patients were also asked to complete self-report measures of pain intensity, NA, and opioid craving. A bootstrapped multiple mediation analysis was used to examine the mediating role of patients' pain intensity and opioid craving in the association between NA and prescription opioid misuse. Consistent with previous research, we found a significant association between NA and prescription opioid misuse. Interestingly, results revealed that opioid craving, but not pain intensity, mediated the association between NA and opioid misuse. The Discussion addresses the potential psychological and neurobiological factors that might contribute to the interrelationships among NA, opioid craving, and prescription opioid misuse in patients with pain. The clinical implications of our findings are also discussed.

PERSPECTIVE

Our study provides new insights into the factors that underlie the association between negative affect and prescription opioid misuse in patients with chronic pain. Our findings could have important clinical implications, particularly for patients being prescribed opioid medication, and for reducing rates of opioid misuse in patients with pain.

A comparison of physical and psychological features of responders and non-responders to cervical facet blocks in chronic whiplash

Background

Cervical facet block (FB) procedures are often used as a diagnostic precursor to radiofrequency neurotomies (RFN) in the management of chronic whiplash associated disorders (WAD). Some individuals will respond to the FB procedures and others will not respond. Such responders and non-responders provided a sample of convenience to question whether there were differences in their physical and psychological features. This information may inform future predictive studies and ultimately the clinical selection of patients for FB procedures.

Methods

This cross-sectional study involved 58 individuals with chronic WAD who responded to cervical FB procedures (WAD_R); 32 who did not respond (WAD_NR) and 30 Healthy Controls (HC)s. Measures included: quantitative sensory tests (pressure; thermal pain thresholds; brachial plexus provocation test); nociceptive flexion reflex (NFR); motor function (cervical range of movement (ROM); activity of the superficial neck flexors during the cranio-cervical flexion test (CCFT). Self-reported measures were gained from the following questionnaires: neuropathic pain (s-LANSS); psychological distress (General Health Questionnaire-28), post-traumatic stress (PDS) and pain catastrophization (PCS). Individuals with chronic whiplash attended the laboratory once the effects of the blocks had abated and symptoms had returned.

Results

Following FB procedures, both WAD groups demonstrated generalized hypersensitivity to all sensory tests, decreased neck ROM and increased superficial muscle activity with the CCFT compared to controls (p < 0.05). There were no significant differences between WAD groups (all p > 0.05). Both WAD groups demonstrated psychological distress (GHQ-28; p < 0.05), moderate post-traumatic stress symptoms and pain catastrophization. The WAD_NR group also demonstrated increased medication intake and elevated PCS scores compared to the WAD_R group (p < 0.05).

Conclusions

Chronic WAD responders and non-responders to FB procedures demonstrate a similar presentation of sensory disturbance, motor dysfunction and psychological distress. Higher levels of pain catastrophization and greater medication intake were the only factors found to differentiate these groups.

Sex differences in the stability of conditioned pain modulation (CPM) among patients with chronic pain

OBJECTIVES

To examine the temporal stability of conditioned pain modulation (CPM), formerly termed diffuse noxious inhibitory controls, among a sample of patients with chronic pain. The study also examined the factors that might be responsible for the stability of CPM.

DESIGN, SUBJECTS, AND METHODS

In this test-retest study, patients underwent a series of standardized psychophysical pain-testing procedures designed to assess CPM on two separate occasions (i.e., baseline and follow up). Patients also completed self-report measures of catastrophizing (Pain Catastrophizing Scale [PCS] and negative affect [NA]).

RESULTS

Overall, results provided evidence for the stability of CPM among patients with chronic pain. Results, however, revealed considerable sex differences in the stability of CPM. For women, results revealed a significant test-retest correlation between baseline and follow-up CPM scores. For men, however, the test-retest correlation between baseline and follow-up CPM scores was not significant. Results of a Fisher's Z-test revealed that the stability of CPM was significantly greater for women than for men. Follow-up analyses revealed that the difference between men and women in the stability of CPM could not be accounted for by any demographic (e.g., age) and/or psychological factors (PCS and NA).

CONCLUSIONS

Our findings suggest that CPM paradigms possess sufficient reliability to be incorporated into bedside clinical evaluation of patients with chronic pain, but only among women. The lack of CPM reproducibility/stability observed among men places limits on the potential use of CPM paradigms in clinical settings for the assessment of men's endogenous pain-inhibitory function.

Kampo Diagnostic Procedure, Fuku shin, Could Be a Useful Diagnostic Tool for Psychopathological Patients Suffering from Chronic Pain

Kampo, or traditional Japanese herbal medicine, has been used for clinical practice in Japan. The most appropriate Kampo formula should be chosen for each individual based on specific diagnostic procedures. Fuku shin, the abdominal exam, is one of the most important diagnostic procedures. There are several Fukushos (abdominal conformations). Depression and anxiety have been shown to be related to Shin ka hi koh, epigastric obstructive hardness, and neuroses have an association with Kyoh kyoh ku man, hypochondriac distress. The aim of our study was to compare Fukushos at each level of depression and anxiety symptoms and to assess the associations between occurrence and pain catastrophizing. Two hundred and twenty-nine patients were assigned to high-, moderate-, or low-level anxiety-depression groups based on the hospital anxiety and depression scale and were investigated for occurrence of major Fukushos. Moreover, the associations between occurrence and the pain catastrophizing scale (PCS) were analyzed. The moderate and high anxiety-depression groups showed a higher occurrence of Shin ka hi koh [low, 29%; moderate, 51%; high, 67%] (P < 0.0001). In contrast, the relationship between the occurrence of Kyoh kyoh ku man and the PCS showed a significant albeit small correlation (r_s = 0.1296, n = 229, P = 0.0491).

Efficacy of therapeutic fluoroscopy-guided lumbar spine interventional procedures

PURPOSE

To evaluate the benefit of fluoroscopy-guided lumbar spine interventional procedures in treatment of low back pain.

METHODS

This prospective descriptive study was performed on 60 patients with back/radicular pain after showing no improvement with conservative treatment.

RESULTS

One hundred and two injection sessions were done (average 1.7 injection per patient). Caudal and lumbar transforaminal injections were effective in 55.9% and 78.5%, respectively. Facet and sacroiliac interventions were effective in 28.3% and 10%, respectively. Complications occurred in 20% of the procedures.

CONCLUSION

Lumbar injections improved pain/disability related to discogenic lumbar spinal diseases. Efficacy of facet and sacroiliac injections is limited.

Relationship of negative affect and outcome of an opioid therapy trial among low back pain patients

OBJECTIVES

Patients with chronic noncancer pain frequently report symptoms of depression and anxiety (negative affect), which are associated with higher ratings of pain intensity and a greater likelihood of being prescribed chronic opioid therapy. The purpose of this secondary analysis was to test the hypothesis that initial levels of negative affect can predict treatment-related outcomes in a double-blind, placebo-controlled study of extended-release (ER) hydromorphone among opioid-tolerant patients with chronic low back pain.

METHODS

Four hundred fifty-nine (N = 459) patients participated in the titration/conversion phase of a multicenter study, of which 268 were randomized to receive once-daily hydromorphone or placebo. All patients completed the Hospital Anxiety and Depression Scale (HADS) at baseline and were divided evenly into Low (N = 157), Moderate (N = 155), and High (N = 147) negative affect groups based on their scores. Group differences in numerical pain intensity measures at home and in the clinic, Roland-Morris Disability ratings, and measures of symptoms from the Subjective Opiate Withdrawal Scale (SOWS) throughout the trial were analyzed.

RESULTS

Two hundred sixty-eight of the initial 459 subjects who entered the 2 to 4-week titration/conversion phase (pretreatment) were successfully randomized to either placebo or ER hydromorphone; a total of 110 patients then completed this double-blind phase of the study. Those in the Moderate and High negative affect groups tended to drop out more often during the titration/conversion phase because of the adverse effects or lack of efficacy of their prescribed opioid than those in the Low negative mood group (P < 0.05). Overall, those patients in the Moderate and High groups reported significantly higher pain intensity scores in at-home and in-clinic pain intensity ratings (P < 0.05), greater disability on the Roland-Morris Scale (P < 0.01), and more withdrawal symptoms on the SOWS (P < 0.05) than those in the Low group. Higher negative affect scores also predicted less favorable ratings of the study drug during the titration phase (P < 0.05). Interestingly, the High negative affect group showed the most improvement in pain in the placebo condition (P < 0.05).

CONCLUSIONS

Negative affect is associated with diminished benefit during a trial of opioid therapy and is predictive of dropout in a controlled clinical trial.

Interventional pain medicine: retreat from the biopsychosocial model of pain

The field of pain medicine has shifted from multidisciplinary rehabilitation to procedure-focused interventional pain medicine (IPM). Considerable controversy exists regarding the efficacy of IPM and its more narrow focus on nociception as an exclusive target of pain treatment. This topical review aims to examine pain research and treatment outcome studies that support a biopsychosocial model of pain, and to critique the clinical practice of IPM given its departure from the premises of a biopsychosocial model. A modern definition of pain and findings from clinical and basic science studies indicate that pain-related psychological factors are integral to pain perception. The clinical viability of IPM is challenged based upon its biomedical view of peripheral nociception as a primary source of pain and the potential of this viewpoint to foster maladaptive pain attributions and discourage the use of pain coping strategies among chronic pain patients. IPM should adopt a biopsychosocial perspective on pain and operate within a framework of multidisciplinary pain rehabilitation to improve its effectiveness.

Factors determining the success of radiofrequency denervation in lumbar facet joint pain: a prospective study

BACKGROUND AND AIMS

Radiofrequency denervation (RF) of the lumbar facet joints has been shown to be effective in well-selected patients. However, long-term success varies between studies. We evaluated the influence of selected psychosocial and constitutional factors on the outcome of RF, expressed as the duration of pain relief.

METHODS

This prospective observational study included 44 patients who received RF denervations at the University Hospital of Berne. Success was defined as at least 50% pain reduction 7-21 days, 6 months and 1 year after RF therapy. The Cox-regression analysis was performed to evaluate the influence of the following factors on the duration of success: age, sex, depression, work inability and previous surgery.

RESULTS

Complete follow-up was available for 41 patients. The success rate 7-21 days after the denervation was 76%. It decreased to 32% at 6 months and to 22% at 1 year. The median success duration was 17 weeks (95% CI 10-26). The Cox-regression analysis showed a significant shorter duration of success for patients with depression (hazard ratio [HR] 2.97, 95% CI 1.32-6.65), previous surgery (HR 2.39, 95% CI 1.10-5.21) and number of treated joints (HR 1.95 for each increase in the number of joints, 95% CI 1.14-3.33). In bivariate analyses, only depression was kept to be significant.

CONCLUSIONS

Depression seems to be related with a short duration of success. Based on these findings, a comprehensive study is warranted to evaluate whether psychosocial factors have to be considered when recruiting patients for radiofrequency denervation.

The impact of placebo, psychopathology, and expectations on the response to acupuncture needling in patients with chronic low back pain

Comorbid psychopathology is a variable not explored in the acupuncture RCTs that could explain whether subgroups of patients with chronic low back pain have differential responses to acupuncture or placebo treatments. This was a controlled, blinded, crossover trial of verum acupuncture and validated sham acupuncture in 40 CLBP patients, with a Low or High level of psychiatric comorbidity. They completed a 0 to 10 rating scale for pain at the beginning and end of each treatment session, and rated their expectations for change in pain. Verum acupuncture was performed at Large Intestine 4 on the dorsal right hand for 30 minutes by a licensed acupuncturist. Data analysis used percent improvement in pain as the primary outcome for each of the treatment sessions. Both groups (21 Low and 19 High) reported significant analgesia with verum acupuncture needling, mean 33%, P = .9 for difference between groups; and with placebo, 26%, P = .09. In both groups, expectations were only a significant predictor of verum acupuncture response, P = .002, such that those with greater expectations had greater pain relief. Psychiatric comorbidity does not significantly impact acupuncture or placebo acupuncture analgesia in CLBP. It does not affect the positive impact of expectations on reported pain relief from real acupuncture.

PERSPECTIVE

Psychiatric comorbidity may predict differences between acupuncture and placebo responses, not otherwise seen in the RCTs for low back pain. Using a blinded, crossover design, we report that it does not predict outcome, nor does it seem to modify the effect of expectancy (a known predictor) on acupuncture response.

Evidence-based radiology (part 1): Is there sufficient research to support the use of therapeutic injections for the spine and sacroiliac joints?

INTRODUCTION

This review article addresses the best evidence currently available for therapeutic injection therapy for conditions targeting the spine and sacroiliac joints. The article is presented by spinal region. Controversies and areas of interest for further studies are identified.

DISCUSSION

There is conclusive evidence supporting the effectiveness of the caudal approach for the administration of epidural steroid injections for patients with low back pain from a variety of causes. In general, there is moderate-to-strong evidence supporting the use of transforaminal therapeutic epidural injections for lumbar nerve-root compression and facet injections for joint pain arising from these joints in the cervical, thoracic and lumbar spine, but further subgroup analysis is needed to help predict which specific patients may receive the most benefit from these procedures.

CONCLUSION

No randomized controlled trials, meta-analyses or systematic reviews addressing the effectiveness of therapeutic sacroiliac joint injections have been found. For some injections, corticosteroids may not provide better outcomes compared to local anesthetic injections alone.