The Sensitization Model to Explain How Chronic Pain Exists Without Tissue Damage

The interaction of nurses with chronic pain patients is often difficult. One of the reasons is that chronic pain is difficult to explain, because no obvious anatomic defect or tissue damage is present. There is now enough evidence available indicating that chronic pain syndromes such as low back pain, whiplash, and fibromyalgia share the same pathogenesis, namely, sensitization of pain modulating systems in the central nervous system. Sensitization is a neuropathic pain mechanism in which neurophysiologic changes may be as important as behavioral, psychologic, and environmental mechanisms. The sensitization model provides nurses with an opportunity to explain pain as a physical cause related to changes in the nervous system. This explanation may improve the patient's motivation to discuss the importance of psychosocial factors that contribute to the maintenance of chronic pain. In this article, sensitization is described as a model that can be used for the explanation of the existence of chronic pain. The sensitization model is described using a metaphor. The sensitization model is a useful tool for nurses in their communication and education toward patients. (C) 2012 by the American Society for Pain Management Nursin

Neuropathic Pain Mechanisms in Patients with Chronic Sports Injuries: A Diagnostic Model Useful in Sports Medicine?

Objective. The pathophysiology of chronic sports injuries such as overuse or tendinopathy remains largely unknown. With this exploratory study, we aim to detect signs of sensitization of the nervous system. Sensitization is an indication of the involvement of neuropathic mechanisms in patients with chronic sports injuries. Design. Sensory descriptors were assessed by means of a neuropathic pain questionnaire (DN4-interview) and by three methods of sensory testing. The test results were integrated in a scoring system. Setting. Patients were recruited from an outpatient clinic of a University Medical Centre and at primary care physical therapy practices. Patients. Fifteen athletes with a unilateral chronic sports injury were included. Outcome Measures. All subjects filled out the seven-items of the DN4-interview to assess sensory descriptors. Next, the presence of brush-evoked allodynia was assessed and pain thresholds with Von Frey monofilaments and a pressure algometer were measured in all patients to determine signs of sensitization. Results. Based on the scoring system, in 4 out of 15 patients (27%) the presence of sensitization could be detected. In two other patients, signs of hypoalgesia were observed. Conclusions. The involvement of sensitization as an explanation for the pain in chronic sports injuries is credible in a considerable proportion of patients. With respect to treatment, the establishment of such neuropathic pain mechanisms is of clinical significance

Quantitative sensory testing with Von Frey monofilaments in patients with allodynia - What are we quantifying?

The International Association for the Study of Pain defines allodynia as pain due to a stimulus that does not normally provoke pain and hyperalgesia as an increased response to a stimulus, which is normally painful. However, does "normally painful" mean "any stimulation of nociceptors" or "the subjective pain response?" We argue that "normally painful" should not mean "any stimulation of nociceptors," as Von Frey monofilaments may evoke a pricking sensation-which implies the involvement of nociceptors-without necessarily leading to a subjective pain perception. In this paper, we propose that the diagnosis of either allodynia or hyperalgesia should be based on the patient's report, that is, painful versus not painful, rather than on the (sub) type of afferent fiber involved

Psychological Distress and Widespread Pain Contribute to the Variance of the Central Sensitization Inventory:A Cross-Sectional Study in Patients with Chronic Pain

Objectives: Central sensitization (CS) implies increased sensitivity of the nervous system, resulting in increased pain sensitivity as well as widespread pain. Recently, the Central Sensitization Inventory (CSI) was developed to assess symptoms of CS and central sensitivity syndromes. The aim of this study was to examine the convergent validity of the CSI by comparing the outcome to psychosocial factors and clinical features of CS. Methods: In a cross-sectional explorative study, patients with chronic pain completed multiple questionnaires, including the CSI, Pain Catastrophizing Scale, and Symptom Checklist 90, for psychological distress, duration of pain, intensity of pain, widespread pain, and lateralization of pain. Based on bivariate correlations, relevant predictors of CS were selected and used to fit an exploratory structural equation model (SEM) of CS. Results: In total, 114 patients with chronic pain were included, 56.1% being women. The average pain duration was 88 months. The mean total score on the CSI was 36.09 (15.26). The CSI was strongly related to known contributing and related factors of CS. SEM analysis showed that both psychological distress and widespread pain contributed significantly to the variance in symptoms of CS in patients with chronic pain. Conclusion: In this study, the convergent validity of the CSI was measured with demonstration of a strong relationship between contributing factors and clinical features of CS. These findings of convergent validity, considering former studies of the CSI, underline the use of the questionnaire in the clinical practice

Effectiveness of a Primary Care Multidisciplinary Treatment for Patients with Chronic Pain Compared with Treatment as Usual

To manage chronic pain, multidisciplinary interventions have been increasingly deployed, mostly in secondary or tertiary care settings. Evidence on the effectiveness of multidisciplinary intervention within primary care is scarce. This study examined the effectiveness of a primary care multidisciplinary treatment for chronic pain compared with treatment as usual (TAU). The intervention consisted of pain neuroscience education and treatment by a GP, psychologist, and physiotherapist. Both groups filled out patient-reported outcome measures at baseline, 6 months, and 12 months. The results indicated there were no statistically significant differences for the primary outcomes of pain intensity, number of pain sites, and health-related quality of life (HR-QoL). There was a statistically significant difference in the secondary outcome perceived health change in favor of the intervention group. None of the other differences were statistically significant. A post-hoc analysis showed that there were statistically significant effects on patients’ illness perceptions in favor of the intervention group. Based on the results, the findings do not support effectiveness of a low intensity outpatient multidisciplinary primary care treatment to treat chronic pain compared with TAU. However, as a result of several study limitations, it is considered unwarranted to conclude that multidisciplinary treatment in primary care is not valuable at all

Effectiveness of a Primary Care Multidisciplinary Treatment for Patients with Chronic Pain Compared with Treatment as Usual

To manage chronic pain, multidisciplinary interventions have been increasingly deployed, mostly in secondary or tertiary care settings. Evidence on the effectiveness of multidisciplinary intervention within primary care is scarce. This study examined the effectiveness of a primary care multidisciplinary treatment for chronic pain compared with treatment as usual (TAU). The intervention consisted of pain neuroscience education and treatment by a GP, psychologist, and physiotherapist. Both groups filled out patient-reported outcome measures at baseline, 6 months, and 12 months. The results indicated there were no statistically significant differences for the primary outcomes of pain intensity, number of pain sites, and health-related quality of life (HR-QoL). There was a statistically significant difference in the secondary outcome perceived health change in favor of the intervention group. None of the other differences were statistically significant. A post-hoc analysis showed that there were statistically significant effects on patients’ illness perceptions in favor of the intervention group. Based on the results, the findings do not support effectiveness of a low intensity outpatient multidisciplinary primary care treatment to treat chronic pain compared with TAU. However, as a result of several study limitations, it is considered unwarranted to conclude that multidisciplinary treatment in primary care is not valuable at all