Pain
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Postoperative pain is a major clinical problem imposing a significant burden on patients and society. In a survey 2 years after orthopedic surgery, 57% of patients reported persisting postoperative pain. However, only limited progress has been made in the development of safe and effective therapies to prevent the onset and chronification of pain after orthopedic surgery. ⋯ Percutaneous vagus nerve stimulation also improved locomotor coordination and accelerated bone healing. In the dorsal root ganglia, vagal stimulation inhibited the activation of glial fibrillary acidic protein-positive satellite cells but without affecting microglial activation. Overall, these data provide novel evidence supportive of the use of pVNS to prevent postoperative pain and inform translational studies to test antinociceptive effects of bioelectronic medicine in the clinic.
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Facial grimacing is used to quantify spontaneous pain in mice and other mammals, but scoring relies on humans with different levels of proficiency. Here, we developed a cloud-based software platform called PainFace ( http://painface.net ) that uses machine learning to detect 4 facial action units of the mouse grimace scale (orbitals, nose, ears, whiskers) and score facial grimaces of black-coated C57BL/6 male and female mice on a 0 to 8 scale. ⋯ By analyzing the frequency distribution of grimace scores, we found that mice spent 7x more time in a "high grimace" state following laparotomy surgery relative to sham surgery controls. Our study shows that PainFace reproducibly quantifies facial grimaces indicative of nonevoked spontaneous pain and enables laboratories to standardize and scale-up facial grimace analyses.
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Meta Analysis
The effect of unpredictability on the perception of pain: a systematic review and meta-analysis.
Despite being widely assumed, the worsening impact of unpredictability on pain perception remains unclear because of conflicting empirical evidence, and a lack of systematic integration of past research findings. To fill this gap, we conducted a systematic review and meta-analysis focusing on the effect of unpredictability on pain perception. We also conducted meta-regression analyses to examine the moderating effect of several moderators associated with pain and unpredictability: stimulus duration, calibrated stimulus pain intensity, pain intensity expectation, controllability, anticipation delay, state and trait negative affectivity, sex/gender and age of the participants, type of unpredictability (intensity, onset, duration, location), and method of pain induction (thermal, electrical, mechanical pressure, mechanical distention). ⋯ However, several significant moderators were found, ie, targeted stimulus pain intensity, expected pain intensity, and state negative affectivity. Trait negative affectivity and uncontrollability showed no significant effect, presumably because of the low number of included studies. Thus, further investigation is necessary to clearly determine their role in unpredictable pain perception.
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Randomized Controlled Trial Multicenter Study
Parental experience of neonatal pain research while participating in the Parental touch trial (Petal).
Parental involvement in neonatal comfort care is a core component of family-centred care. Yet, parents experience a range of positive and negative feelings when providing pain-relieving interventions for their infants. Parents of infants who participated in the Parental touch trial ( Petal ), a multicentre randomised controlled trial investigating the impact of gentle parental touch on neonatal pain, were asked to complete an anonymous survey. ⋯ Parents reported that providing gentle touch to their children during painful procedures was associated with positive emotions, such as feeling "useful" (64%) and "reassured" (53%). Furthermore, nearly all parents (98%) were pleased to have participated in the Petal trial and would consider, or maybe consider, participating in further research studies. These results underscore the importance of structuring trials around parental involvement and providing opportunities for parents to be involved in providing comfort to their infants during necessary painful clinical procedures.