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Background and purpose – Pain catastrophizing contributes to acute and long-term pain after total knee arthroplasty (TKA) but currently there are only limited treatment options. This study investigates the effectiveness of patient education in pain coping among patients with moderate to high pain catastrophizing score before TKA. Secondary outcomes were physical function, quality of life, self-efficacy, and pain catastrophizing.Patients and methods – The study was a parallel-group randomized controlled trial including patients with moderate to high levels of pain catastrophizing. 60 patients were recruited from December 2015 to June 2018. The mean age of the patients was 66 (47-82) years and 40 were women. The patients were randomized to either cognitive-behavioral therapy (CBT) based pain education or usual care. The primary outcome measure was pain under activity measured with the Visual Analog Scale (VAS). All outcomes were measured preoperatively, at 3 months, and at 1 year after surgery.Results – We found no difference in the primary outcome measure, VAS during activity, between the 2 groups but both groups had large reductions over time. The CBT-based pain education group reduced their VAS score by 37 mm (95% CI 27-46) and the control group by 40 mm (CI 31-49). We found no statistically significantly differences between the 2 groups in any of the secondary outcomes.Interpretation – Future research is warranted to identify predictors of persistent pain and interventions for the approximately 20% of patients with persisting pain after a TKA.
Learn More >Fibromyalgia syndrome (FMS) is a chronic pain syndrome characterized by widespread pain and a variety of non-pain symptoms. Central sensitivity phenomena are found consistently in FMS. Additionally, several researchers proclaimed that a subgroup of FMS patients may present with unrecognized peripheral small fiber neuropathy (SFN). Laser-evoked brain potentials (LEP) are considered as a reliable method for the functional assessment of the thermo-nociceptive system, including the evaluation of SFN.
Learn More >The nitric-oxide donor nitroglycerin (NTG) administration induces a facilitation of nociceptive pathways in episodic migraine. This study aims to test the hypothesis that induced spinal sensitization could be more pronounced in patients affected by high frequency migraine (HF-MIG) respect to low frequency migraine (LF-MIG).We enrolled 28 patients with LF-MIG (1-5 migraine days/month), 19 patients with HF-MIG (6-14 migraine days/month) and 21 healthy controls (HC). Spinal sensitization was evaluated with the neurophysiological recording of the temporal summation threshold (TST) of the nociceptive withdrawal reflex at the lower limb. TST was recorded at baseline and 30, 60 and 120 minutes after NTG administration (0.9 mg sublingual).Spinal sensitization was detected in LF-MIG at 60 (p=0.010) and 120 minutes (p=0.001) and in HF-MIG at 30 (p=0.008), 60 (p=0.001) and 120 minutes (p=0.001) after NTG administration. TST did not change in HC (p=0.899). Moreover, TST reduction was more pronounced in HF-MIG respect to LF-MIG (p=0.002).The percentage of patients who developed a migraine-like headache after NTG was comparable in the two migraine groups (LF-MIG: 53.6%, HF-MIG: 52.6%, p=0.284), while no subjects in HC group developed a delayed-specific headache. Notably, the latency of headache onset was significantly shorter in the HF-MIG group when compared to the LF-MIG group (p=0.015).Our data demonstrate a direct relationship between migraine frequency and both neurophysiological and clinical parameters, to suggest an increasing derangement of the nociceptive system control as the disease progresses, probably as a result of the interaction of genetic and environmental factors.
Learn More >αB-crystallin (CRYAB) is a small heat shock protein that is able to inhibit neuroinflammatory responses under various pathological conditions. Some studies have proven that neuroinflammatory mechanisms play important roles in bone cancer pain (BCP). However, whether CRYAB participates in the maintenance of BCP has not yet been examined.
Learn More >The aim of this study was to evaluate the possible association between polymorphisms in the catechol-O-methyltransferase (COMT) and β2-adrenergic receptor (ADRB2) genes and muscular temporomandibular disorders (TMD). This was a case-control study. Individuals were evaluated using the Research Diagnostic Criteria for Temporomandibular Disorders and were divided into three groups: unaffected (no TMD) (n=154); exclusively muscular TMD (n=49); exclusively articular TMD (n=49). Genomic DNA was obtained from saliva samples, and single nucleotide polymorphisms in the COMT (rs165774, rs6269, rs9332377) and ADRB2 (rs2053044, rs1042713, rs1042714) genes were investigated. The TT genotype for the COMT rs9332377 gene was highly associated with the presence of muscular TMD (P= 0.03). With respect to the ADRB2 gene, the non-polymorphic AA genotype in the rs1042713 region was more prevalent in the articular TMD group than in the muscular TMD group (P= 0.05). This study supports the hypothesis that alterations in the COMT and ADRB2 genes influence the muscular pathophysiology.
Learn More >Chronic pain is a common condition that affects the physical, emotional, and mental well-being of patients and can significantly diminish their quality of life. Due to growing concerns about the substantial risks of long-term opioid use, both governmental agencies and professional societies have recommended prioritizing the use of nonpharmacologic treatments, when suitable, in order to reduce or eliminate the need for opioid use. The use of 10 kHz spinal cord stimulation (10 kHz SCS) is one such nonpharmacologic alternative for the treatment of chronic, intractable pain of the trunk and limbs. This review examines published clinical data regarding the efficacy of 10 kHz SCS for decreasing chronic pain in patients and its potential to reduce or eliminate opioid usage. Multiple prospective and retrospective studies in patients with intractable pain demonstrated that 10 kHz SCS treatment provided ≥50% pain relief in >70% patients after at least 1 year of treatment. Pain relief with 10 kHz SCS therapy ranged from 54% to 87% in the studies. More importantly, the mean daily dose of opioids required by patients in these studies was reduced after 10 kHz SCS treatment, and on average over 60% patients in studies either reduced or eliminated opioids at the last follow-up.
Learn More >Prospective cohort study OBJECTIVE.: To evaluate the course of orofacial pain and jaw disability in relation to neck pain, neck disability and psychosocial factors at the acute stage and the chronic stage after whiplash trauma.Summary of Background Data Many individuals report chronic pain in the orofacial region after whiplash trauma. The possible association between whiplash trauma and orofacial pain is debated. Prospective studies are therefore needed to evaluate the development of orofacial pain after whiplash trauma.
Learn More >Tissue injury produces a delicate balance between latent pain sensitization (LS) and compensatory endogenous opioid receptor analgesia that continues for months, even after re-establishment of normal pain thresholds. To evaluate the contribution of mu (MOR), delta (DOR), and/or kappa (KOR) opioid receptors to the silencing of chronic postoperative pain, we performed plantar incision at the hindpaw, waited 21 days for the resolution of hyperalgesia, and then intrathecally injected subtype-selective ligands. We found that the MOR-selective inhibitor CTOP (1-1000 ng) dose-dependently reinstated mechanical hyperalgesia. Two DOR-selective inhibitors naltrindole (1-10 μg) and TIPP[Ψ] (1-20 μg) reinstated mechanical hyperalgesia, but only at the highest dose that also produced itching, licking, and tail biting. Both the prototypical KOR-selective inhibitors nor-BNI (0.1-10 μg) and the newer KOR inhibitor with more canonical pharmocodynamic effects, LY2456302 (0.1-10 μg), reinstated mechanical hyperalgesia. Furthermore, LY2456302 (10 μg) increased the expression of phosphorylated signal-regulated kinase (pERK), a marker of central sensitization, in dorsal horn neurons but not glia. Sex studies revealed that LY2456302 (0.3 μg) reinstated hyperalgesia and pERK expression to a greater degree in female as compared to male mice. Our results suggest that spinal MOR and KOR, but not DOR, maintain LS within a state of remission to reduce the intensity and duration of postoperative pain, and that endogenous KOR but not MOR analgesia is greater in female mice.
Learn More >The aim of this study was to measure the interictal burden (IIB) associated with cluster headache (CH).
Learn More >Chronic postsurgical neuropathic pain (CPSNP) is frequent. While prevalence varies considerably according to type of operation and means of evaluation, it can reach 37% following breast surgery. Identification of risk factors related to the procedure and to the patient and taking into account the development of new, minimally invasive surgical techniques is increasingly nerve-sparing and reduces the likelihood of injury. CPSNP diagnosis in daily practice is facilitated by simple and quickly usable tools such as the NP4 4-question test. Management is based on pharmacological (analgesics, antiepileptics, antidepressants, local anesthetics) and non-pharmacological (kinesitherapy, neurostimulation, psychotherapy) approaches. In light of the present review of the literature, the authors, who constitute an expert group specialized in pain management, anesthesia and surgery, express their support for topical treatments (lidocaine, capsaicin) in treatment of localized postsurgical neuropathic pain in adults.
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