The journal of pain : official journal of the American Pain Society
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Two strategies should greatly improve pain management while minimizing opioid abuse. The first strategy involves the systematic implementation in every clinical practice of "universal precautions," a set of procedures that help physicians implement opioid therapy in a safe and controlled manner. These procedures include: 1) carefully assessing the patient's risk for opioid abuse; 2) selecting the most appropriate opioid therapy; 3) regularly monitoring the patient to evaluate the efficacy and tolerability of the treatment and to detect possible aberrant behaviors; and 4) mapping out solutions if abuse and/or addiction is detected, or in case of treatment failure. The second strategy involves the use of opioid formulations designed to deter or prevent product tampering and abuse. Results of clinical trials of new formulations of existing opioids (including oxycodone, morphine, and hydromorphone) suggest the potential for reduced abuse liability and, if approved, will be evaluated after launch for reduced real-world abuse. Integration of these formulations in clinical practices based on universal precautions should help further minimize the risk of opioid abuse while fostering appropriate prescribing to patients with indications for opioid therapy. ⋯ Undertreated pain and prescription opioid abuse remain important public health problems. In the absence of strong empirical evidence, common sense dictates that a universal-precautions approach-a systematic and easily adopted process that clinicians can quickly put into practice-is advised to promote safe opioid prescribing. Abuse- and tamper-resistant opioid formulations are emerging tools that may enhance safe opioid prescribing; further research and postmarketing analysis will clarify their utility and role in clinical practice.
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Randomized Controlled Trial
Capsaicin-induced central sensitization evokes segmental increases in trigger point sensitivity in humans.
This study investigated whether inducing central sensitization evokes segmental increases in trigger point pressure sensitivity. We evoked central sensitization at the C(5) segment and validated its presence via mechanical cutaneous sensitivity (brush allodynia) testing. Trigger point pressure sensitivity was quantified using the pain pressure threshold (PPT) value. A 50 cm(2) area of the C(5) dermatome at the right lateral elbow was pretreated with 45 degrees heat for 10 minutes. Test subjects (n = 20) then received topical capsaicin cream (0.075%; Medicis, Toronto, Canada) to the C(5) dermatome, whereas control subjects (n = 20) received a topical placebo cream (Biotherm Massage, Montreal, Canada). PPT readings were recorded from the infraspinatus (C(5,6)) and gluteus medius (L(4,5)S(1)) trigger points at zero (pre-intervention), 10, 20, and 30 minutes after intervention; all PPT readings were normalized to pre-intervention (baseline) values. The difference between the PPT readings at the 2 trigger point sites represents the direct influence of segmental mechanisms on the trigger point sensitivity at the infraspinatus site (PPT(seg)). Test subjects demonstrated statistically significant increases in Total Allodynia scores and significant decreases in PPT(seg) at 10, 20, and 30 minutes after application, when compared with control subjects. These results demonstrate that increases in central sensitization evoke increases in trigger point pressure sensitivity in segmentally related muscles. ⋯ Myofascial pain is the most common form of musculoskeletal pain. Myofascial trigger points play an important role in the clinical manifestation of myofascial pain syndrome. Elucidating the role of central sensitization in the pathophysiology of trigger points is fundamental to developing optimal strategies in the management of myofascial pain syndrome.
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The Chronic Pain Coping Inventory (CPCI) is a frequently used measure that assesses 8 categories of coping strategies that patients might use to cope with chronic pain. Despite its good psychometric properties and widespread use, the instrument has not been tested for its applicability and validity in non-Western populations, such as among Chinese. This study evaluated the reliability and validity of a Chinese translation of the 42-item CPCI (ChCPCI-42) in a sample of Chinese patients with chronic pain (n = 208). In addition to the ChCPCI-42, the patients were administered the Chronic Pain Grade (CPG) questionnaire, the Pain Catastrophizing Scale (PCS), the Centre for Epidemiological Studies-Depression Scale (CES-D), and questions assessing sociodemographic characteristics. Results of confirmatory factor analyses revealed that of the ChCPCI-42 8 scales, 6 demonstrated acceptable-to-good data-model fit (CFI >or= 0.90) and 2 demonstrated medium fit (CFI >or= 0.85). The 8 scales demonstrated adequate to good internal consistency (Cronbach alpha, 0.69 to 0.79) and correlated with CES-D, PCS, pain intensity, and disability in expected directions. Results of hierarchical multiple regression analyses showed that the ChCPCI-42 scales predicted concurrent depression (F (8,177) = 3.07, P < .01) and pain disability (F (1, 179) = 4.35, P < .001) scores, the Task Persistence scale being the strongest unique predictor among the 8 scales. The findings support the factorial validity and reliability of a 42-item CPCI that can be used among Chinese patients with chronic pain. ⋯ The report outlines the first validation of the CPCI for use in Hong Kong Chinese. This makes available a suitable instrument for chronic pain research in the Southern Chinese population and will help to elucidate similarities and differences in pain coping between Chinese and other ethnic groups.
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The functions of small fibers can be impaired in peripheral neuropathies, and screening tests for clinical use are required. To verify whether intraepidermal stimulation (IES) is useful for assessing the functions of Adelta fibers in the superficial layer, we investigated sensory thresholds and evoked cortical responses in healthy volunteers before and after a transdermal administration of lidocaine. Pain and tactile thresholds were studied using IES and transcutaneous electrical stimulation (TS), respectively, in 10 healthy volunteers before, and 1 hour, 3 hours, and 5 hours after a local anesthesia with lidocaine. Cortical potentials evoked with IES and TS were also studied in 12 healthy volunteers before and 5 hours after the anesthesia. Although the local anesthesia had no effect on the evoked potentials or the tactile threshold for TS, it markedly increased the pain threshold and almost abolished the evoked potentials for IES. These results suggest that IES is a sensitive tool for detecting functional changes of cutaneous Adelta fibers. ⋯ Compared with other methods of stimulation used to investigate Adelta fiber function, our method is easy to apply and less invasive and can stimulate any site of the body. Therefore, it should be useful as a screening test for patients with neuropathy.
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The aim of this present study is to test the hypotheses that the 18 predetermined sites of examination for tender points (TP sites) in fibromyalgia syndrome (FMS) are myofascial trigger points (MTrPs), and that the induced pain from active MTrPs at TP sites may mimic fibromyalgia pain. Each TP site was evaluated with manual palpation followed by intramuscular electromyographic (EMG) registration of spontaneous electrical activity to confirm or refute the existence of an MTrP in 30 FMS patients. Overall spontaneous pain intensity and pain pattern were recorded before manual identification of MTrPs. Local and referred pain pattern from active MTrPs were drawn following manual palpation at TP sites. ⋯ This article underlies the importance of active MTrPs in FMS patients. Most of the TP sites in FMS are MTrPs. Active MTrPs may serve as a peripheral generator of fibromyalgia pain and inactivation of active MTrPs may thus be an alternative for the treatment of FMS.