Browse by Audience
The differentiation of chronic primary pain syndromes into those with widespread versus regional musculoskeletal pain has been characterized by controversial discussions about common or distinct mechanisms and core clinical and sensory criteria. For example, the recent revision of fibromyalgia criteria has discarded sensory characteristics such as number of "tender points". This study examined empirical evidence related to this diagnostic shift and aimed to identify basic sensory-clinical pain phenotypes in patients with chronic local primary pain (chronic primary back pain, CBP) and patients with chronic widespread primary pain (fibromyalgia syndrome, FMS). Combined sensory-clinical pain phenotypes of 185 patients with prior CBP and FMS diagnoses were derived by a stepwise data-reduction through descriptive statistical, correlational, principal components and latent class analyses. Clusters were cross-validated by linear discriminant analysis. Four clusters of patients were identified, requiring four pressure pain sensitivity markers (number of sensitive tender and control points, pain intensity and pressure pain threshold at the trapezius) and two clinical pain characteristics (pain regions, present pain intensity). Subsequent discriminant analysis revealed that three discriminant functions of pressure sensitivity markers sufficed to differentiate the clusters. These sensory-clinical phenotypes differed also in somatic symptoms and impairment but neither in psychopathology nor in psychosocial co-factors. The results highlight the relevance of sensory testing in combination with clinical pain assessment in chronic primary pain syndromes.
Learn More >Pain after total knee arthroplasty (TKA) is a prevalent condition. This study compared the effectiveness of tapentadol extended release (ER) 50 mg x 2, oxycodone controlled release (CR) 10 mg x 2 and placebo; as added to a multimodal analgesic regime both in-hospital and at home the first week after TKA. The study was randomized and blinded for investigators, staff, outcome assessors and patients. Follow-up included pain intensity on mobilization, pain at rest, worst pain in the previous 24 hours, and adverse effects measured on 0-10 numeric rate scales. A total of 134 patients in three study groups received their allocated intervention and were included in the analysis. The primary outcome pain on mobilization the 7 first postoperative days reported as mean pain Area Under the Curve (AUC) was 528.1 (SD 267.5, IQR 356.6 to 665.4) for placebo, 427.2 (SD 203.9, IQR 303.6 to 544.3) for tapentadol ER and 507.9 (SD 243.7, IQR 292.4 to 686.8) for oxycodone CR (p=0.12). With the exception of constipation being less prevalent in the tapentadol ER group (p=0.02), we found no significant differences between treatment groups for the secondary outcomes. Tapentadol ER as an add-on to multimodal analgesia did not significantly improve pain relief when compared to oxycodone CR or placebo. Constipation was lowest in the tapentadol ER group.
Learn More >Descending facilitatory circuitry that involves the rostroventromedial medulla (RVM) exerts a significant role in the development of antinociceptive tolerance and hyperalgesia following chronic morphine treatment. The role of the RVM in the development of antinociceptive tolerance to oxycodone, another clinically used strong opioid, is not yet known. Ketamine, an NMDA receptor antagonist, attenuates opioid antinociceptive tolerance, but its effect on RVM cell discharge in opioid tolerant animals is not known. Here, we compared chronic effects of morphine and oxycodone on the discharge properties of RVM cells and attempted to attenuate chronic treatment-induced changes with ketamine. Parallel recordings of RVM cell discharge and limb withdrawal response were performed under light pentobarbital anesthesia in male rats following sustained systemic treatment with morphine or oxycodone at equianalgesic doses. Ongoing activity and the response to noxious heat and pinch were determined in pronociceptive RVM ON-cells and antinociceptive OFF-cells on the sixth treatment day. Proportions of RVM cell types were not changed. Chronic oxycodone induced antinociceptive tolerance both in limb withdrawal and RVM cell activity. Chronic morphine induced antinociceptive tolerance in limb withdrawal that was accompanied by pronociceptive heat response changes in RVM ON- and OFF-cells. A behaviorally subantinociceptive dose of acute ketamine reversed antinociceptive tolerance both to morphine and oxycodone in limb withdrawal and reversed the chronic morphine-induced pronociceptive discharge changes in RVM cells. The results indicate that an NMDA receptor-dependent descending pronociceptive circuitry involving the RVM has an important role in behavioral antinociceptive tolerance to morphine but not oxycodone.
Learn More >Cognitive behavioral therapy (CBT) is a psychological intervention that involves development of coping strategies to reduce the experience of pain. Although CBT is a promising intervention to reduce headache days in patients with migraine, it may not be effective for all patients. Thus, there is a need to identify markers that could predict which patients will respond to CBT. We aimed to determine if baseline brain function and amygdalar connectivity, assessed by fMRI, or pain modulation capacities, assessed by the conditioned pain modulation (CPM) response, can predict a reduction in headache days after CBT in adolescents with migraine. Patients with migraine (n = 20; age range 10-17 years) completed 8 weekly CBT sessions. The CPM response was examined in the trapezius and the leg. Headache days significantly decreased after CBT (p<0.001). Greater functional connectivity before CBT between the right amygdala and frontal gyrus, anterior cingulate cortex, and precentral gyrus was related to greater headache reduction after CBT. Greater reduction in headache days after CBT was related with less efficient CPM response before CBT at the trapezius (r=-0.492, p=0.028) but not at the leg. This study found that headache reduction after CBT was related to right amygdala connectivity with frontal and sensorimotor regions at baseline as well as baseline pain modulation capacities. These findings suggest that individual differences in brain function and pain modulation can be associated with clinical improvements and help with determination of CBT responsiveness.
Learn More >Adolescent idiopathic scoliosis is one of the most common spinal deformities in children and adolescents requiring extensive surgical intervention. Due to the nature of surgery, spinal fusion increases their risk of experiencing persistent postsurgical pain. Up to 20% of adolescents report pain for months or years after corrective spinal fusion surgery.
Learn More >Chronic pain is common following stroke, however there is little known about the treatments for pain that are being accessed by stroke survivors, nor their perceived effectiveness.
Learn More >To examine the peripheral nervous system (PNS) in spinal cord injured (SCI) patients using two novel methods: (1) MScanFit MUNE; a motor unit number estimation method detecting motor unit loss and (2) muscle velocity recovery cycles (MVRCs) measuring muscle membrane properties which has previously shown depolarization of the muscle membrane in denervated muscles.
Learn More >To examine the association between initial patterns of prescription opioid supply (POS) and risk of all-cause mortality among an insured opioid-naïve patient population in the United States (US).
Learn More >Evaluate the effectiveness of an intensive interdisciplinary pain treatment (IIPT) day-hospital program as compared to an outpatient multimodal treatment (MMT) for youth with chronic pain.
Learn More >The opioid epidemic is a significant public health problem largely driven by opioid prescriptions for chronic pain. Among those with chronic pain, anxiety and depressive symptoms have been linked to opioid misuse, and individual differences in anxiety and depressive symptoms among adults with chronic pain may be important for better understanding pain. Yet, little work has examined mechanisms that may link anxiety and depressive symptoms to opioid misuse among adults with chronic pain. Anxiety sensitivity, or the fear of anxiety-related physical sensations, may be one candidate construct that has been linked independently to anxiety and depressive symptoms as well as opioid misuse.
Learn More >