The journal of pain : official journal of the American Pain Society
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Recent evidence points to an association between experimental pain measures obtained preoperatively and acute postoperative pain (POP). We hypothesized that pain temporal summation (TS) might be an additional predictor for POP insofar as it represents the neuroplastic changes that occur in the central nervous system following surgery. Therefore, a wide range of psychophysical tests (TS to heat and mechanical repetitive stimuli, pain threshold, and suprathreshold pain estimation) and personality tests (pain catastrophizing and anxiety levels) were administered prior to thoracotomy in 84 patients. POP ratings were evaluated on the 2nd and 5th days after surgery at rest (spontaneous pain) and in response to activity (provoked pain). Linear regression models revealed that among all assessed variables, enhanced TS and higher pain scores for mechanical stimulation were significantly associated with greater provoked POP intensity (overall r2 = 0.225, P = .008). Patients who did not demonstrate TS to both modalities reported lower scores of provoked POP as compared with patients who demonstrated TS in response to at least 1 modality (F = 4.59 P = .013). Despite the moderate association between pain catastrophizing and rest POP, none of the variables predicted the spontaneous POP intensity. These findings suggest that individual susceptibility toward a greater summation response may characterize patients who are potentially vulnerable to augmented POP. ⋯ This study proposed the role of pain temporal summation assessed preoperatively as a significant psychophysical predictor for acute postoperative pain intensity. The individual profile of enhanced pain summation is associated with the greater likelihood of higher postoperative pain scores.
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The purpose of this study was to investigate the prevalence and demographic risk factors of chronic pain and its comorbidity with depression. Computer-assisted telephone interviewing was utilized to obtain a representative community sample in the state of Michigan (n = 1,179). The prevalence of chronic pain due to any cause was 21.9%. Approximately 35% of participants with chronic pain also had comorbid depression (7.7% of the entire sample). Depression was not associated with pain types or sites. A multinomial-regression analysis revealed several demographic correlates of chronic pain and depression. Participants with chronic pain or comorbid pain and depression were more likely to be older, female, employed less than full-time, and have less education than persons without either condition. Logistic regression analyses showed that younger participants were more likely to have comorbid pain and depression than chronic pain only. A similar but marginally significant effect was found for African American participants. Compared to the depression-only group, those in the comorbid group were more likely to be women and middle-aged. These findings provide additional evidence on the prevalence of comorbid pain and depression in the community and suggest that certain demographic groups with chronic pain may especially benefit from depression screenings. ⋯ This article reports on the prevalence of chronic pain and co-occurring depression in a representative community sample. The high prevalence rates of pain and comorbid depression point to the clinical importance of assessing depression in chronic pain samples.
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Neuropathic pain (NP) is a difficult issue, particularly in cancer which is a dynamic condition where multiple pain etiologies are concomitantly present. Cancer pain is often labeled as mixed mechanism pain and is not easily classified as exclusively nociceptive or NP. The aim of this study was to explore the value of evaluation tools such as Neuropathic Pain Questionnaire (NPQ), complete and short form (NPQ-SF), Leeds Assessment of Neuropathic Signs and Symptoms (LANSS) and Neuropathic Pain Symptom Inventory (NPSI). The secondary outcome was to evaluate the response to opioid titration, according to the hierarchical classification of definite, possible and unlikely NP. A consecutive sample of patients referred for treatment of cancer-related pain were eligible for participation in the study. The inclusion criterion was uncontrolled cancer pain requiring adjustment of opioid therapy. Patients were clinically classified into tertiles based according to graded evidence of nervous system lesion: definite NP, possible NP, or unlikely NP. Pain and symptoms intensities were measured before (T0) and at the end of opioid titration (T1). Patients were titrated with escalating doses of opioids, supported by symptomatic drugs, changing the route of administration, or by opioid switching according to the clinical response. At T1 the opioid response was clinically graded from 1 to 4. Opioid escalation index was calculated. A single independent investigator, blinded to the clinical assessment and treatment, collected data from NPQ, NPQ-SF, LANSS Pain Scale, and NPSI. One hundred and sixty-seven patients concluded the study. Sixty, thirty-six, and seventy-one patients were clinically assessed as having definite NP, possible NP, or unlikely NP, respectively. A relationship between the values of the assessment tools and clinician rating was found. Patients with the highest values of assessment tools were also more likely to be clinically labeled as definite NP, although sensibility and specificity were low. Patients with a clinical diagnosis of definite NP, possible NP, or unlikely NP showed significant differences in opioid response (P < .0005). Patients with "unlikely NP" had a lower pain intensity at T1 (P < .05), and patients with "definite NP" required more intensive treatment. Patients requiring more aggressive treatment showed significantly higher values of Opioid Escalation Index (OEI)mg. ⋯ Screening tools may provide a basis to suggest a common language in cancer pain syndromes. A hierarchical grouping seems to be more flexible and fits cancer patient characteristics. This study also confirms that opioids are clinically effective in "definite NP" conditions although a more aggressive treatment requiring careful utilization of opioids and symptomatic drugs is strictly necessary.