Brain imaging of neuropathic pain

Many studies have focused on defining the network of brain structures involved in normal physiological pain. The different dimensions of pain perception (i.e., sensory discriminative, affective/emotional, cognitive/evaluative) have been shown to depend on different areas of the brain. In contrast, much less is known about the neural basis of pathological chronic pain. In particular, it is unclear whether such pain results from changes to the physiological "pain matrix". We review here studies on changes in brain activity associated with neuropathic pain syndromes-a specific category of chronic pain associated with peripheral or central neurological lesions. Patients may report combinations of spontaneous pain and allodynia/hyperalgesia-abnormal pain evoked by stimuli that normally induce no/little sensation of pain. Modern neuroimaging methods (positron emission tomography (PET) and functional MRI (fMRI)) have been used to determine whether different neuropathic pain symptoms involve similar brain structures and whether these structures are related to the physiological "pain matrix". PET studies have suggested that spontaneous neuropathic pain is associated principally with changes in thalamic activity and the medial pain system, which is preferentially involved in the emotional dimension of pain. Both PET and fMRI have been used to investigate the basis of allodynia. The results obtained have been very variable, probably reflecting the heterogeneity of patients in terms of etiology, lesion topography, symptoms and stimulation procedures. Overall, these studies indicated that acute physiological pain and neuropathic pain have distinct although overlapping brain activation pattern, but that there is no unique "pain matrix" or "allodynia network".     

癌性疼痛的控制及护理

目的：探讨癌症患者疼痛及护理对策。方法：对100例癌症患者采用线性视觉模拟评估疼痛的程度。结果：本组100例,75例得到有效控制,24例未能得到有效控制。其中轻度疼痛占43.9%,中度疼痛占40.1%,重度疼痛占16.0%。在重度疼痛中,强阿片类药物应用仅达52.1%,在中度疼痛中,弱阿片类药物应用仅达52.2%。结论：实施心理护理、疼痛控制、营养支持等优质护理是改善患者生活质量,延长寿命的关键。     

A look at chronic pain in dogs

Chronic pain can be found in all mammals that have a nociceptive pathway. It is defined as pain that extends beyond the normal time of healing. This article deals with chronic pain that affects canine patients. Chronic pain and depression have both been shown to occur in mammals. Chronic pain can be divided into inflammatory pain, non-osteoarthritis–non-malignant pain and cancer pain. The pet owner is key in the recognition of chronic pain in dogs. There are validated chronic pain scales available for dogs. The article will discuss various examples of chronic pain that affects dogs and ways to alleviate the effects of this pain in selected disease processes.     

Does past pain influence current pain: biological and psychosocial models of sex differences.

Previous studies have generally indicated sizeable sex differences for both laboratory pain reactivity and clinical pain reports. Numerous biological and psychosocial models have been invoked to account for these findings, but the laboratory and clinical findings have generally been examined in isolation. This paper reviews data which show a relationship between past clinical pain experiences and current responses to experimentally induced pain. Individuals with a greater pain history tend to show lower pain tolerance. Since women often have high pain experience levels and lower pain tolerance, one might ask whether the two factors are related. We review several models, based upon concepts of neonatal differences in pain reactivity, hypervigilance following early pain experiences, and concepts of peripheral and central sensitization or plasticity which might help to bridge the gap between clinical and experimental findings.     

Sex differences in the adequacy of pain management among patients referred to a multidisciplinary cancer pain clinic

Few studies have evaluated sex differences in the adequacy of pain management in cancer. Existing studies have been marked by methodological limitations and results have been mixed. The present study sought to determine whether sex was associated with pain severity and pain management in cancer patients newly referred by their primary oncology team to a multidisciplinary cancer pain clinic. One hundred thirty-one cancer patients completed the Brief Pain Inventory-Short Form and medical chart review was conducted to obtain patients' clinical characteristics and pain treatment data. There were no differences between males and females in ratings of worst pain in the last week. Females were significantly less likely to have been prescribed high potency opioids by their primary oncology team and significantly more likely to report inadequate pain management as measured by Pain Management Index scores. These results suggest a sex bias in the treatment of cancer pain and support the routine examination of the effect of sex in cancer pain research.     

From documentation to the problem: controlling postoperative pain

PROBLEM. Adequate pain control continues to be an enigma in the face of the Joint Commission (TJC) well‐intended pain management standards. Notable in the pain standards is the mandate to make pain the fifth vital sign to increase pain visibility and awareness. METHOD. The following databases were searched: EBSCOHost, CINHAL, PubMed Central, Medline, and government/societies sites for guidelines on pain control. Various search terms used included pain, post operative pain, pain control, pain as the 5th vital sign, pain documentation, pain assessment, Joint Commission Pain Standard, PRN effectiveness, and pay‐for‐performance. FINDINGS. Accredited facilities are mandated to have plans to assess for pain and evaluate pain management effectiveness. These mandates have necessitated a flurry of initiatives and programs by hospitals and healthcare facilities focusing on documentation processes to meet TJC compliance. Notable programs include Pain as the 5th Vital Sign and PRN (as needed) effectiveness documentation. Many facilities have programs to assess and document pain but lack programs that effectively control patient's pain. CONCLUSION. This article is a call for facilities to refocus on pain control. A need to evaluate current programs by facilities is evident. Studies show that Pain as the 5^th Vital Sign and PRN effectiveness documentation are not effective and invariably have not met the goals of TJC pain standard—adequate and effective pain control.     

Why study pain? A qualitative analysis of medical and nursing faculty and students' knowledge of and attitudes to cancer pain management

Although effective means for pain management have long been available, cancer pain remains widely undertreated. Surveys of medical personnel have revealed knowledge deficits and attitudinal barriers to pain management, but have not determined why such attitudes persist and how they may be addressed in medical and nursing curricula. This paper presents findings from a qualitative study of the beliefs and attitudes toward pain and cancer pain management held by medical and nursing students and faculty who participated in the Cancer Education Module for the Management of Pain (CEMMP) project. Analysis centered on informants' prioritization and knowledge of pain and cancer pain management and on the meanings informants assigned to pain in a clinical context. Themes in prioritization included the importance of learning about pain versus cancer pain and the responsibility of primary care providers versus specialists for pain and cancer pain management. Themes in informants' knowledge of pain included knowledge deficits about medications and adjunct therapies and the presence of pain management in the curriculum, and the role of knowledgeable faculty members and mentors in the dissemination of information about pain management. Themes in the meanings informants' assigned to pain included opioidphobia, and the (inter-)subjectivity of pain. The discussion focuses in particular on tensions within the prioritization, knowledge and meanings of pain that must be resolved before students can be appropriately educated for optimal pain management.     

Epidural steroid injections are useful for the treatment of low back pain and radicular symptoms: Pro

Epidural steroid injection has been used to treat low back pain for many decades. Numerous randomized trials have examined the efficacy of this approach. This review details the findings of older systematic reviews, newer randomized controlled trials, and two recent systematic reviews that examine the effectiveness of this treatment. Collectively, studies in acute radicular pain due to herniated nucleus pulposus have failed to show that epidural steroid injection reduces long-term pain or obviates the need for surgery. Similarly, there is scant evidence that epidural steroids have any beneficial effect in those with acute low back pain without leg pain or in those with chronic low back or leg pain. However, most studies have demonstrated more rapid resolution of leg pain in those who received epidural steroid injections versus those who did not. The role of epidural steroid injections in the management of acute radicular pain due to herniated nucleus pulposus is simply to provide earlier pain relief.     

首钢地区癌痛普查及社区医护人员癌痛知识调查

目的：对首钢地区的肿瘤现患者生活质量及癌痛发生情况进行基线摸底；较全面地调查现患肿瘤病人的数量及癌痛发生率、社区医师的癌痛知识和对癌痛三阶梯方案的认识情况。方法：采用自制问卷调查的方法进行普查。结果：全地区约13万人口中共普查出397位现存癌症患者，现患率30．5／万；其中112人曾存在疼痛，占所有癌症现患者的28．2％，61人仍有疼痛，占总疼痛人数的55％；癌症分期越晚，疼痛发生率越高；总体疼痛控制率低。结论：疼痛患者对癌痛控制的错误认识较多；社区医护人员对癌痛知识的了解较少，缺乏控制癌痛的能力。     

四肢创伤骨折患者急性疼痛的护理管理

近年来,国际疼痛研究协会越来越关注患者的急性疼痛,对于急性疼痛的治疗,医务人员已经从保守治疗变为主动治疗,镇痛方式也逐渐向多模式过渡,但急性疼痛的镇痛不足现象依然存在。对于创伤骨折患者存在的急性疼痛问题,本课题组组建了疼痛护理小组,通过小组的建设,疼痛知识的培训,以及临床实践等活动,提高了护士及患者对疼痛的认知水平,增加了患者实施疼痛自我管理的意识,从而得到专业的疼痛护理。     

Pain as a channelopathy

Mendelian heritable pain disorders have provided insights into human pain mechanisms and suggested new analgesic drug targets. Interestingly, many of the heritable monogenic pain disorders have been mapped to mutations in genes encoding ion channels. Studies in transgenic mice have also implicated many ion channels in damage sensing and pain modulation. It seems likely that aberrant peripheral or central ion channel activity underlies or initiates many pathological pain conditions. Understanding the mechanistic basis of ion channel malfunction in terms of trafficking, localization, biophysics, and consequences for neurotransmission is a potential route to new pain therapies.     

Relationship between pain and vertebral motion in chronic low-back pain subjects

OBJECTIVES: To investigate the relationship between intervertebral motion, intravertebral deformation and pain in chronic low-back pain patients. DESIGN: This study measured vertebral motion of the lumbar spine and associated pain in a select group of chronic low-back pain patients as they performed a standard battery of motions in all planes. BACKGROUND: Numerous studies have demonstrated that individuals with low-back pain have impaired spinal motion, yet few studies have examined the specific relationship between pain and motion parameters. Although it is accepted that the pain in mechanical low-back patients is due to specific spinal motions, no studies have related specific motions to pain measures. METHODS: Percutaneous intra-pedicle screws were placed into the right and left L4 (or L5) and S1 segments of nine chronic low-back pain patients. The external fixator frame was removed following the clinical external fixation test. The 3D locations of the pedicle screws and the level of pain were recorded as the subjects performed a battery of motions. The relationship between the pain and motion parameters was assessed using linear discriminant analysis and neural network models. RESULTS: The neural network model showed a strong relationship between observed and predicted pain (R(2)=0.997). The discriminant analysis showed a weak relationship (R(2)=0.5). CONCLUSIONS: Vertebral motion parameters are strongly predictive of pain in this select group of chronic low-back pain patients. The nature of the relationship is nonlinear and involves interactions; neural networks are able to effectively describe these relationships. RELEVANCE: Specific patterns of intervertebral motion and intravertebral deformation result in pain in chronic low-back pain patients. This substantiates the mechanical back pain aetiology.     

Nursing’s Role in Cancer Pain Management

Nurses have advanced practice, research, and education in the field of cancer pain management. This paper highlights the contributions nurses have made to pain science and practice through literature published in the past 3 years. Work accomplished by nurses is examined in the areas of pain assessment, pain management, intervention-based research, evidence-based practice, patient education, and palliative care. Nurses serve as advocates for empowering patients to engage in self-management of their pain, and offer education and support to patients and families at their most vulnerable times. Nurse researchers have been at the forefront of work to develop and test new instruments and approaches to measure pain, elucidate pain experiences through quantitative and qualitative methodologies, and gauge the quality of pain care for patients and its impact on their caregivers. This research has uncovered many patient, health care professional, and systemic barriers to effective pain control, and has offered feasible solutions to overcoming these barriers.     

Describing and predicting the nature of procedural pain after thermal injuries: implications for research

A prerequisite for studying and treating burn-related pain is the establishment of a good understanding of the nature of burn-related pain. However, in most investigations of pain, researchers have failed to examine pain over time or to create summary scores that capture differences in the nature of the pain experiences of individual patients. For 10 consecutive days, 47 patients treated for burn injuries reported on three aspects of procedural pain: worst pain, sensory pain, and affective pain. Three summary pain scores were constructed for each pain dimension: average pain, variability in pain, and linear change in pain. The authors found considerable variability in pain reports from the same patient and from different patients. Analyses indicated that pain reports decreased over time and that patients who had more trait anxiety reported more pain. Patients with larger burn injuries tended to report more affective pain and tended to have a pattern of high and low pain reports that differed from patients with less severe burn injuries. These findings suggest that adequate assessment of burn pain must occur frequently over the course of a single day, as well as for the duration of each patient's care.     

Pain perception and tolerance in patients with frontotemporal dementia

Pain management in elderly people with cognitive impairment poses special challenges, due to difficulties in pain assessment and specific neurodegenerative changes along pain pathways. Most studies have concentrated on Alzheimer’s disease (AD) patients, in whom some contrasting findings have been found. For example, while psychophysical data suggest a selective blunting of the affective dimension of pain, pain-related fMRI signal increases have also been described. Few data have been reported in patients with frontotemporal dementia (FTD). By electrical stimulation, we have measured pain threshold and pain tolerance in clinically diagnosed FTD patients with SPECT cerebral hypoperfusion. We performed our analysis on two separate and overlapping subgroups selected on the basis of (1) neuropsychological scores below cut-off values (2) a strictly localized frontal and/or temporal hypoperfusion. We observed increased pain threshold in the first group and increased pain threshold and pain tolerance in the second group. Our results suggest differences in pain processing changes in distinct types of dementia, while at the same time caution that pain perception assessment may depend on the criteria adopted for diagnosis.     

Remembrance of labor pain: how valid are retrospective pain measurements?

Recently, several authors have questioned the reliability and validity of relying on retrospective assessment of labor pain. Many studies designed to determine the relationships between psychosocial and demographic factors and pain intensity during labor have relied on such measurements. The purpose of this prospective study was to determine if primiparas and multiparas can accurately remember the pain of labor. Fifty primiparas and 88 multiparas participated in the study. Prospective assessment of in-labor pain was performed using a Visual Analogue Scale (VAS) in 3 phases of labor. Retrospective assessment of labor pain was performed 2 days post partum using the VAS. Results showed that there were significant differences between the amount of actual pain reported and the amount of pain and discomfort remembered by both primiparas and multiparas. The mean rating for remembered discomfort was higher than for remembered pain. The subjects tended to deflate the intensity of their labor pain. The results suggest that previous studies that have relied on retrospective assessments of labor pain may be invalid.     

Women and the Experience of Pain and Opioid Use Disorder: A Literature-based Commentary

It is generally understood that pain experience and opioid abuse have relied on male-dominated models. However, sex and gender play a role in both pain experience and opioid use disorder.Using the previously validated Texas Tech University Health Sciences Center Sex and Gender Specific Health PubMed Advanced Search Tool, the authors used pertinent literature to develop this literature-based commentary on sex and gender differences in pain experience and opioid use disorder. Women report their experience of pain more frequently, have increased rates of diagnoses related to pain, have increased pain sensitivity, and have a variable response to pain and analgesia. This variable response is due to anatomic, physiologic, hormonal, psychological, and social factors that differ by sex and gender. Women have been found to be at greater risk for opioid abuse in all age groups. This may be due to the differences in pain experience, as well as sex and gender differences in prescribing patterns, cultural norms, and the increased likelihood to experience dependency and withdrawal. Approaches to the treatment of opioid use disorder are also subject to sex and gender differences—an area in need of further investigation.     

Audit of cancer pain management in a cancer centre

Despite the availability of effective methods of controlling pain, many patients continue to receive inadequate pain relief. An audit was carried out on a single day to identify the prevalence, severity and management of cancer pain in adults in the two teaching hospitals in the Nottingham Cancer Centre. Of 186 patients with cancer, 52 had experienced pain as a result of their cancer during their admission. Of these 52 patients, 47 were assessed. More than half had unrelieved pain that was 'severe' at it s worst and interfered greatly with activities. Compared with patients whose pain had been relieved, patients with uncontrolled pain were likely to have spent less time in hospital, to have not had a formal assessment or reassessment of their pain and not to have a pain-care plan in the nursing notes or to have been seen by the hospital specialist palliative care team. We use our results to highlight areas of good practice, to identify where improvements could be made, and to inform the development of local standards and future audits.