The journal of pain : official journal of the American Pain Society
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Psychosocial factors that protect against negative outcomes for individuals with chronic pain have received increased attention in recent years. Pain resilience, or the ability to maintain behavioral engagement and regulate emotions as well as cognitions despite prolonged or intense pain, is one such factor. A measure of pain-specific resilience, the Pain Resilience Scale, was previously identified as a better predictor of acute pain tolerance than general resilience. ⋯ A confirmatory factor analysis confirmed the 2-factor structure of the Pain Resilience Scale previously observed among respondents without chronic pain, although one item from each subscale was dropped in the final version. For this chronic pain sample, structural equation modeling showed that pain resilience contributes unique variance to a model including pain acceptance and pain self-efficacy in predicting quality of life and pain intensity. Further, pain resilience was a better fit in this model than general resilience, strengthening the argument for assessing pain resilience over general resilience.
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The number of studies on trigeminal nerve injury using animal models remains limited. A rodent model of trigeminal neuropathic pain was first developed in 1994, in which chronic constriction injury (CCI) is induced by ligation of the infraorbital nerve (IoN). This animal model has served as a major tool to study trigeminal neuropathic pain. Unfortunately, the surgical procedure in this model is complicated and far more difficult than ligation of peripheral nerves (eg, sciatic nerve). The aim of this study was to improve on the current surgical procedure of IoN ligation to induce trigeminal neuropathic pain in rats. We show that the IoN can be readily accessed through a small facial incision. CCI can be induced by ligation of a segment at the distal IoN (dIoN). This dIoN-CCI procedure is simple, minimally invasive, and time-saving. Our data show that the dIoN-CCI procedure consistently induced acute as well as chronic nociceptive behaviors in rats. Daily gabapentin treatment attenuated mechanical allodynia and reduced face-grooming episodes in dIoN-CCI rats. ⋯ The orofacial pain caused by trigeminal nerve damage is severe and perhaps more debilitating than other types of neuropathic pain. However, studies on trigeminal neuropathic pain remain limited. This is largely because of the lack of proper animal models because of the complexity of the existing surgical procedures required to induce trigeminal nerve injury. Our improved dIoN-CCI model is likely to make it more accessible to study the cellular and molecular mechanisms of neuropathic pain caused by trigeminal nerve damage.
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Randomized Controlled Trial Comparative Study
Cost-utility of Group Acceptance and Commitment Therapy for Fibromyalgia versus recommended drugs: An economic analysis alongside a 6-month randomised controlled trial conducted in Spain (EFFIGACT study).
The aim of this study was to analyze the cost utility of a group-based form of acceptance and commitment therapy (GACT) in patients with fibromyalgia (FM) compared with patients receiving recommended pharmacological treatment (RPT) or on a waiting list (WL). The data were derived from a previously published study, a randomized controlled trial that focused on clinical outcomes. Health economic outcomes included health-related quality of life and health care use at baseline and at 6-month follow-up using the EuroQoL and the Client Service Receipt Inventory, respectively. ⋯ Lower direct costs for GACT compared with RPT were due to lower costs from primary care visits and FM-related medications. The incremental cost effectiveness ratios were dominant in the completers' analysis and remained robust in the sensitivity analyses. In conclusion, acceptance and commitment therapy appears to be a cost-effective treatment compared with RPT in patients with FM.
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Fibromyalgia (FM) is a complex syndrome characterized by chronic widespread pain, hyperalgesia, and other disabling symptoms. Although the brain response to experimental pain in FM patients has been the object of intense investigation, the biological underpinnings of painful after-sensations (PAS), and their relation to negative affect have received little attention. In this cross-sectional cohort study, subjects with FM (n = 53) and healthy controls (n = 17) were assessed for PAS using exposure to a sustained, moderately painful cuff stimulus to the leg, individually calibrated to a target pain intensity of 40 of 100. Despite requiring lower cuff pressures to achieve the target pain level, FM patients reported more pronounced PAS 15 seconds after the end of cuff stimulation, which correlated positively with clinical pain scores. Functional magnetic resonance imaging revealed reduced deactivation of the medial temporal lobe (MTL; amygdala, hippocampus, parahippocampal gyrus) in FM patients, during pain stimulation, as well as in the ensuing poststimulation period, when PAS are experienced. Moreover, the functional magnetic resonance imaging signal measured during the poststimulation period in the MTL, as well as in the insular and anterior middle cingulate and medial prefrontal cortices, correlated with the severity of reported PAS by FM patients. These results suggest that the MTL plays a role in PAS in FM patients. ⋯ PAS are more common and severe in FM, and are associated with clinical pain and catastrophizing. PAS severity is also associated with less MTL deactivation, suggesting that the MTL, a core node of the default mode network, may be important in the prolongation of pain sensation in FM.