Current psychological approaches to the management of chronic pain

Pain Pathways and Nervous System Plasticity: Learning and Memory in Pain

Objective This article reviews the structural and functional changes in pain chronification and explores the association between memory and the development of chronic pain. Methods PubMed was searched using the terms "chronic pain," "central sensitization," "learning," "memory," "long-term potentiation," "long-term depression," and "pain memory." Relevant findings were synthesized into a narrative of the processes affecting pain chronification. Results Pain pathways represent a complex sensory system with cognitive, emotional, and behavioral influences. Anatomically, the hippocampus, amygdala, and anterior cortex-central to the encoding and consolidation of memory-are also implicated in experiential aspects of pain. Common neurotransmitters and similar mechanisms of neural plasticity (eg, central sensitization, long-term potentiation) suggest a mechanistic overlap between chronic pain and memory. These anatomic and mechanistic correlates indicate that chronic pain and memory intimately interact on several levels. Longitudinal imaging studies suggest that spatiotemporal reorganization of brain activity accompanies the transition to chronic pain, during which the representation of pain gradually shifts from sensory to emotional and limbic structures. Conclusions The chronification of pain can be conceptualized as activity-induced plasticity of the limbic-cortical circuitry resulting in reorganization of the neocortex. The state of the limbic-cortical network determines whether nociceptive signals are transient or chronic by extinguishing pathways or amplifying signals that intensify the emotional component of nociceptive inputs. Thus, chronic pain can be seen as the persistence of the memory of pain and/or the inability to extinguish painful memories. Ideally, pharmacologic, physical, and/or psychological approaches should reverse the reorganization accompanying chronic pain.

Chronic Pain: Structural and Functional Changes in Brain Structures and Associated Negative Affective States

Chronic pain is a condition in which pain progresses from an acute to chronic state and persists beyond the healing process. Chronic pain impairs function and decreases patients’ quality of life. In recent years, efforts have been made to deepen our understanding of chronic pain and to develop better treatments to alleviate chronic pain. In this review, we summarize the results of previous studies, focusing on the mechanisms underlying chronic pain development and the identification of neural areas related to chronic pain. We review the association between chronic pain and negative affective states. Further, we describe the structural and functional changes in brain structures that accompany the chronification of pain and discuss various neurotransmitter families involved. Our review aims to provide guidance for the development of future therapeutic approaches that could be used in the management of chronic pain.

Predictors of chronic neuropathic pain after scoliosis surgery in children

Background

Numerous publications describe chronic pain following surgery in both adults and children. However, data in the paediatric population are still sparse and both prevalence of chronic pain after surgery and risk factors of this complication still undetermined.

Methods

We prospectively evaluated the prevalence of chronic pain and its neuropathic pain component at 1 year following correction of idiopathic scoliosis in children less than 18 years of age. Pain was defined as the presence of pain (numerical rating scale – NRS ≥4), the presence of signs of neurologic damage within the area of surgery and the presence of the neuropathic symptoms as a DN4 (Douleur Neuropathique 4) questionnaire ≥4. Factors investigated as potentially associated with the presence of a persistent neuropathic pain were: age, weight, the presence of continuous preoperative pain over the 3 months before surgery, surgical characteristics, pain scores during the first five postoperative days, and DN4 at day 3. Statistical analysis employed univariate analysis and a multivariate logistic regression model.

Results

Thirty six patients were included in the study. Nineteen (52.8%) had pain at one year after surgery. Among them 17 (48.2%) had neuropathic pain. Logistic regression found continuous pain over the 3 months preceding surgery and day 1 morphine consumption ≥0.5 mg kg-1 as independent predictors of persistent chronic pain with a neuropathic component. The overall model accuracy was 80.6 and the area under the curve of the model was 0.89 (95% confidence interval 0.78–0.99).

Conclusions

The present study found a high proportion of paediatric patients developing chronic persistent pain after surgical correction of scoliosis diformity. It allows identifying two factors associated with the occurrence of persistent chronic pain with a neuropathic component: the presence of persistent preoperative pain during the 3 months preceeding surgery and postoperative opioid consumption at day 1 –;0.5 mg kg-1

Implication

Patients scheduled for spine surgery and presenting with preoperative pain should be considered at risk of chronic pain after surgery and managed accordingly by the chronic and/or acute pain team. Postoperative opioid consumption should be lowered as possible by using multimodal analgesia and regional analgesia such as postoperative epidural analgesia.

Physical therapy under hypnosis for the treatment of patients with type 1 complex regional pain syndrome of the hand and wrist: Retrospective study of 20 cases

Type 1 complex regional painful syndrome (CRPS-1) has a complex physiopathology. The aim of this study was to evaluate the effectiveness of physical therapy under hypnotherapy to treat this condition. Twenty patients with CRPS-1 at the wrist and hand were evaluated retrospectively: 13 women and 7 men with an average age of 56 years (34-75). Thirteen patients were in the inflammatory phase and 7 in the dystrophic phase. The main endpoints were pain (VAS, analgesic use), stiffness (wrist and finger range of motion), and strength (pinch and grasp). Secondary endpoints were functional scores (QuickDASH, PWRE), patient satisfaction, return to work, and side effects. Results were satisfactory in all cases after 5.4 sessions on average. VAS decreased by 4 points, PWRE-pain by 4.1 points, and analgesic use was limited to paracetamol upon request. Finger and wrist range of motion increased and the QuickDASH decreased by 34 points, PRWE-function by 3.8 points, pinch strength increased 4 points, and grasp strength by 10 points. Return to work was possible in 80% of the cases. All patients were satisfied or very satisfied with the treatment. Physical therapy under hypnosis appears to be an effective treatment for CRPS-1 at the wrist and hand no matter the etiology.

A randomized controlled trial of an online self-management program for adults with arthritis pain

The objective of this RCT was to assess the efficacy of an online pain self-management program with adults who had a self-reported doctor diagnosis of arthritis pain (N = 228). Participants were recruited via flyers and online postings then randomized to the experimental condition or the wait-list control condition. Individuals in the experimental condition reported significantly (1) increased arthritis self-efficacy and (2) reduced pain catastrophizing from baseline to follow up compared to those in the control condition. High user engagement (>204.5 min on the website) was also significantly associated with improved self-management outcomes. These findings suggest that use of an online self-management program may positively impact self-efficacy and catastrophizing among adults with arthritis pain at 6 month follow up. Nonsignificant findings for hypothesized variables such as pain intensity and health behaviors are also discussed. Future longitudinal research is needed to assess if cognitive changes associated with participation in an online self-management program leads to reduced pain.

Electroencephalography-based real-time cortical monitoring system that uses hierarchical Bayesian estimations for the brain-machine interface

In this study, a real-time cortical activity monitoring system was constructed, which could estimate cortical activities every 125 milliseconds over 2,240 vertexes from 64 channel electroencephalography signals through the Hierarchical Bayesian estimation that uses functional magnetic resonance imaging data as its prior information. Recently, functional magnetic resonance imaging has mostly been used in the neurofeedback field because it allows for high spatial resolution. However, in functional magnetic resonance imaging, the time for the neurofeedback information to reach the patient is delayed several seconds because of its poor temporal resolution. Therefore, a number of problems need to be solved to effectively implement feedback training paradigms in patients. To address this issue, this study used a new cortical activity monitoring system that improved both spatial and temporal resolution by using both functional magnetic resonance imaging data and electroencephalography signals in conjunction with one another. This system is advantageous as it can improve applications in the fields of real-time diagnosis, neurofeedback, and the brain-machine interface.

Complementary and Alternative Medicine in the Treatment of Chronic Pelvic Pain in Women: What Is the Evidence?

Chronic pelvic pain (CPP) is defined as pain of at least 6 months' duration that occurs in the lower abdomen or below the umbilicus and has resulted in functional or psychological disability or required intervention and treatment. Therapeutic interventions center around the treatment of CPP as a diagnosis in and of itself, and treatment of specific disorders that may be related to CPP. A multidisciplinary approach for diagnosis and treatment seems to be most effective for symptomatic relief. This paper reviews the evidence for such interventions as psychological treatments including the use of complementary and alternative medicine techniques for CPP in women. Unfortunately, finding the best evidence in this setting is difficult as only very few randomized controlled trials are available. A combination of treatments is usually required over time for the treatment of refractory CPP. The multifactorial nature of CPP needs to be discussed with the patient and a good rapport as well as a partnership needs to be developed to plan a management program with regular followup. Promotion of a multidisciplinary approach which includes complementary and alternative medicine techniques in managing CPP in women seems to yield the best results.

Unpleasant subjective emotional experiencing of pain

The field of pain medicine that once began as a supportive and compassionate care, adding value to the management of acute and chronic ailments, has now transformed into a vital and essential specialty with structured training programs and service units with professionals dedicating their careers to it. The expansion of understanding of the direct relationship of pain relief to the quality of life, uncovering of neuronal pathways, and technological advances in imaging as well as in interventional techniques have all contributed to this phenomenal growth. However, there is a growing concern whether the training programs and the specialized practitioners are gradually limiting their skilled inputs primarily within the sensory realm of the pain experience with sophisticated interventional techniques and relegating its subjective and emotional dimensions to perfunctory realms within the schema of service provision. While the specialty is still young, if we can understand the inherent aspect of these dimensions within the pain experience and acknowledge the gaps in service provision, it may be possible to champion development of truly comprehensive pain relief programs that responds effectively and ethically to a patient's felt needs. This article attempts to position the subjectivity of pain experience in context and surface the need to design complete systems of pain relief services inclusive of this dimension. It presents authors’ review of literature on perspectives of ‘unpleasant subjective emotional experiencing of the pain” to elucidate possible clinical implications based on the evidences presented on neuro-biology and neuro-psychology of the pain experience; the aim being to inspire systems of care where this dimension is sufficiently evaluated and managed.

Neuropathic pain referrals to a multidisciplinary pediatric cancer pain service

Neuropathic pain (NP) in children with cancer is not well characterized. In a retrospective review of patient data from a 3.5-year period, we describe the prevalence of NP and the characteristics, duration of follow-up, and interventions provided for NP among patients referred to a pediatric oncology center's pain management service. Fifteen percent (66/439) of all referrals to our pain service were for NP (56/323 patients [17%]; 34 male, 22 female). The NP patient group had 1,401 clinical visits (778 inpatient visits [55.5%] and 623 outpatient visits [44.5%]). Patients with NP had a significantly greater mean number of pain visits per consultation (p = .008) and significantly more days of pain service follow-up (p < .001) than did other patients. The most common cause of NP was cancer treatment rather than the underlying malignancy. Pharmacologic management of NP was complex, often comprising three medications. Nonpharmacologic approaches were used for 57.6% of NP referrals. Neuropathic pain is less frequently encountered than non-NP in children with cancer; nevertheless, it is more difficult to treat, requiring longer follow-up, more clinical visits, complex pharmacologic management, and the frequent addition of nonpharmacologic interventions.

Expert panel consensus recommendations for the pharmacological treatment of acute pain in the Middle East region

The findings of an expert panel convened to review critically how best to apply evidence-based guidelines for the treatment of acute pain in the Middle East region are presented. The panel recommended a three-step treatment protocol. Patients with mild-to-moderate levels of acute pain should be treated with paracetamol (step 1). If analgesia is insufficient after 1-2 days, a selective cyclo-oxygenase-2 inhibitor or, if gastrointestinal safety and bleeding risk are not an issue, a non-specific nonsteroidal anti-inflammatory drug, should be used (step 2). If analgesia remains inadequate, treatment with tramadol, or paracetamol plus codeine/tramadol is recommended (step 3). Patients reporting severe pain should be referred to a pain clinic or specialist for opioid analgesic treatment. Measures of pain and functioning that have been validated in Arabic, with culturally appropriate and easy to understand descriptors, should be used. Early and aggressive acute pain management is important to reduce the risk of pain becoming chronic, especially in the presence of neuropathic features.

Effects of yoga interventions on pain and pain-associated disability: a meta-analysis

We searched databases for controlled clinical studies, and performed a meta-analysis on the effectiveness of yoga interventions on pain and associated disability. Five randomized studies reported single-blinding and had a higher methodological quality; 7 studies were randomized but not blinded and had moderate quality; and 4 nonrandomized studies had low quality. In 6 studies, yoga was used to treat patients with back pain; in 2 studies to treat rheumatoid arthritis; in 2 studies to treat patients with headache/migraine; and 6 studies enrolled individuals for other indications. All studies reported positive effects in favor of the yoga interventions. With respect to pain, a random effect meta-analysis estimated the overall treatment effect at SMD = -.74 (CI: -.97; -.52, P < .0001), and an overall treatment effect at SMD = -.79 (CI: -1.02; -.56, P < .0001) for pain-related disability. Despite some limitations, there is evidence that yoga may be useful for several pain-associated disorders. Moreover, there are hints that even short-term interventions might be effective. Nevertheless, large-scale further studies have to identify which patients may benefit from the respective interventions.

PERSPECTIVE

This meta-analysis suggests that yoga is a useful supplementary approach with moderate effect sizes on pain and associated disability.

Intersection of chronic pain treatment and opioid analgesic misuse: causes, treatments, and policy strategies

Treating chronic pain in the context of opioid misuse can be very challenging. This paper explores the epidemiology and potential treatments for chronic pain and opioid misuse and identifies educational and regulation changes that may reduce diversion of opioid analgesics. We cover the epidemiology of chronic pain and aberrant opioid behaviors, psychosocial influences on pain, pharmacological treatments, psychological treatments, and social treatments, as well as educational and regulatory efforts being made to reduce the diversion of prescription opioids. There are a number of ongoing challenges in treating chronic pain and opioid misuse, and more research is needed to provide strong, integrated, and empirically validated treatments to reduce opioid misuse in the context of chronic pain.

Insight into pain-inducing and -related gene expression: a challenge for development of novel targeted therapeutic approaches

The multidimensional issue of pain in relation to the need for efficient treatment has been the focus of extensive research. Gaining insight into the molecular mechanisms of pain and identifying specific genes and proteins as possible drug targets is strongly required considering that not all patients can be adequately treated with the currently available drugs. This up-to-date review aimed to summarize the findings of recent proteomic and genomic approaches in different types of pain to comment on their potential role in pain signaling pathways and to evaluate their possible contribution to the development of novel and possibly more targeted pain therapeutic strategies. Although pain treatment strategies have been greatly improved during the past century, no ideal targeted pain treatment has been developed. The development of modern and accurate platforms of technology for the study of genetics and physiology of pain has led to the identification of an increased number of altered genes and proteins that are involved in pain-related pathways. Through genomics and proteomics, pain-related genes and proteins, respectively, may be identified as diagnostic markers or drug targets improving therapeutic strategies. Furthermore, such molecular mediators of pain may reveal novel strategies for individualized pain management. The utilization of unique experimental approaches (through specific animal models) as well as powered genetic association studies conducted on appropriate populations is more than essential.

Survey results of pain treatments in adults with cerebral palsy

OBJECTIVE

The aims of this study were to identify the types and frequencies of pain treatments used by individuals with cerebral palsy, examine the perceived effectiveness of these treatments, and identify the types of healthcare providers that were accessed for pain-related services.

DESIGN

A cross-sectional survey design was used. A total of 83 adults (mean [SD] age, 40.3 [13.6] yrs) with cerebral palsy indicated their pain location and intensity during the past 3 mos. Next, they indicated their use of 24 different pain treatments and the effectiveness of each. Finally, participants indicated the frequency of pain-related healthcare visits to specific providers over the past 6 mos.

RESULTS

Of the participants, 63% reported experiencing chronic pain and rated their pain intensity over the past week as 5.1 of 10, on average. The most common pain locations were the lower back, hips, and legs. Physical interventions (e.g., physical therapy, strengthening) were the most common pain treatments reportedly used and were rated as moderately effective. Many other treatments were also used, and participants sought pain-related care from a variety of providers.

CONCLUSIONS

Although participants reportedly accessed pain care from a variety of providers and perceived that several types of treatments were effective, many of the treatments rated as effective were rarely used or provided. Future research using clinical trial methods would further elucidate the specific pain treatments that are most beneficial for adults with cerebral palsy.

Comorbid pain and opioid addiction: psychosocial and pharmacological treatments

Treating comorbid pain (nonmalignant) and opioid addiction is a complex endeavor that requires cooperation of multi-modal treatment teams incorporating pharmacological, psychological, and social components. There are multiple barriers for patients, mental health practitioners, and physical health practitioners to provide complete treatment for this difficult treatment population. In this article, we will review which treatments have been empirically validated in this treatment population, where further research is required, and considerations for potential "best approaches" to use for patient treatment while waiting for empirically validated treatment data. We will also discuss some complementary and alternative medicine approaches that have empirical validity in treating either pain or addiction individually, though empirical validity for the treatment of comorbid pain and addiction has not been established.

The relation of pain and caregiver burden in informal older adult caregivers

OBJECTIVE

Pain in older adults is highly prevalent and although informal caregiving is commonly provided by an older cohort, the relationship between pain and caregiving has seldom been examined. Our goal was to study the associations between caregiver pain, depression, and caregiver burden in a sample of older adult caregivers.

DESIGN

Questionnaires were completed by 116 caregivers (mean age=73.34) to measure the caregivers' overall pain, chronic pain status, caregiver burden and its five dimensions, depression, and the care recipients' level of disability. Hierarchical linear regression analyses evaluated the extent to which care recipient and caregiver variables, including caregiver pain and depression, were related to high levels of caregiver burden.

RESULTS

The overall level of pain reported by the caregiver was a significant predictor of overall caregiver burden and the emotional and physical dimensions of caregiver burden, whereas a number of care recipient variables (e.g., disability level) were significant predictors of the social, emotional, and time dependence dimensions of caregiver burden.

CONCLUSIONS

This is the first study to investigate the relationships among caregiver pain and caregiver burden in informal older adult caregivers. We conclude that the role of caregiver pain has been greatly underestimated in the caregiver burden literature and suggest a need for interdisciplinary collaboration for effective management of caregiver burden in older adults.

Psychological treatment of chronic pain

Psychological treatment has emerged as a common component of a multidimensional and interdisciplinary plan of pain care for many persons with persistent pain. Treatments are informed by a biopsychosocial model of pain and a long history of psychological research that has identified the central role of behavioral, cognitive, and emotional factors that are believed to contribute to the perpetuation, if not the development, of chronic pain and pain-related disability and emotional distress. Empirically supported self-regulatory, behavioral, cognitive-behavioral, and acceptance and commitment interventions are reviewed, and current and future interventions are highlighted. Important issues related to individual differences and disparities in the experience of pain and pain treatment are discussed. In particular, race and ethnicity are considered, and special considerations for the management of pain in children and older adults are discussed.

Influence of comorbidity with depression on interdisciplinary therapy: outcomes in patients with chronic low back pain

INTRODUCTION

Our previous work showed higher tumour necrosis factor (TNF)-α levels in patients with chronic low back pain (cLBP) compared to healthy controls. However, patients with depression as a comorbidity did not have higher TNF-α levels in comparison to patients without depression. In this study we investigated the influence of depression on therapy outcomes such as TNF-α serum levels, pain intensity and back function in patients with cLBP. Our hypothesis was that patients with both cLBP and depression benefit no less than patients with cLBP alone from the multidisciplinary pain therapy.

METHODS

A total of 58 patients with cLBP alone or with both cLBP and depression were age- and sex-matched with 29 healthy controls. Serum concentrations of TNF-α were assayed at the beginning of the study (T0) and 10 days (T1), 21 days (T2), and 180 days (T3) later. The clinical outcomes such as pain intensity, as well as back function, sleep, exercise, alcohol and nicotine consumption were documented. In the first three weeks, all patients underwent multidisciplinary therapy based upon biological, psychological, physical and psychosocial components.

RESULTS

Over the whole course there were no differences in TNF-α level between cLBP patients with and without depression. At T0, both cLBP patients with (cLBP+DE) and without (cLBP) depression showed significantly higher TNF-α serum levels (P = 0.002 for cLBP+DE, P = 0.004 for cLBP) than healthy controls (HC) that normalized after 10 days of therapy and remained similar to healthy controls. During the follow-up, the depression scales were normalised and pain intensity was significantly reduced. Both evidences processed parallel to the reduction of TNF-α levels, which correlates neither with depression score nor with pain intensity at any time point.

CONCLUSIONS

Depression as a comorbidity to chronic low back pain did not influence the serum TNF-α level in the course of six months, but seemed to affect the success of therapy. cLBP patients with comorbidity of depression benefit from multidisciplinary pain therapy not only to the same extent but also to a greater degree than cLBP patients without depression.

How neuroimaging studies have challenged us to rethink: is chronic pain a disease?

In this review, we present data from functional, structural, and molecular imaging studies in patients and animals supporting the notion that it might be time to reconsider chronic pain as a disease. Across a range of chronic pain conditions, similar observations have been made regarding changes in structure and function within the brains of patients. We discuss these observations within the framework of the current definition of a disease.

PERSPECTIVE

Neuroimaging studies have made a significant scientific impact in the study of pain. Knowledge of nociceptive processing in the noninjured and injured central nervous system has grown considerably over the past 2 decades. This review examines the information from these functional, structural, and molecular studies within the framework of a disease state.

The influence of negative emotions on pain: behavioral effects and neural mechanisms

The idea that pain can lead to feelings of frustration, worry, anxiety and depression seems obvious, particularly if it is of a chronic nature. However, there is also evidence for the reverse causal relationship in which negative mood and emotion can lead to pain or exacerbate it. Here, we review findings from studies on the modulation of pain by experimentally induced mood changes and clinical mood disorders. We discuss possible neural mechanisms underlying this modulatory influence focusing on the periaqueductal grey (PAG), amygdala, anterior cingulate cortex (ACC) and anterior insula as key players in both, pain and affective processing.

Individual differences in opioid efficacy for chronic noncancer pain

OBJECTIVE

Over a decade ago, Jamison noted the lack of studies that identify patient profiles or specific groups that might be best suited for opioid treatment of chronic noncancer pain.

METHODS

This paper reviews the studies that provide evidence for individual differences in opioid analgesia for chronic noncancer pain.

RESULTS

What we have found is that few investigations have addressed these important aspects of pain treatment. The most consistent finding is that depression and anxiety are associated with increased risk for drug abuse and decreased opioid efficacy.

DISCUSSION

The question remains whether the psychologic disorders antedated the pain condition or whether the experience of chronic pain exerts psychologic pressures that cause changes in behavior and psychologic processes. Additionally, the overall pattern suggests that younger age is predictive of opioid abuse and greater opioid efficacy. We also present a brief review of biologic mechanisms that support individual differences on opioid analgesia.