Pain
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Nearly all amputees continue to feel their missing limb as if it still existed, and many experience chronic phantom limb pain (PLP). What is the origin of these sensations? There is currently a broad consensus among investigators that PLP is a top-down phenomenon, triggered by loss of sensory input and caused by maladaptive cortical plasticity. We tested the alternative hypothesis that PLP is primarily a bottom-up process, due not to the loss of input but rather to exaggerated input, generated ectopically in axotomized primary afferent neurons in the dorsal root ganglia (DRGs) that used to innervate the limb. ⋯ The suppression of PLP and npPLS could also be demonstrated using dilute lidocaine concentrations that are sufficient to suppress DRG ectopia but not to block the propagation of impulses generated further distally in the nerve. PLP is driven primarily by activity generated within the DRG. We recommend the DRG as a target for treatment of PLP and perhaps also other types of regional neuropathic pain.
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Headaches are thought to result from the activation and sensitization of nociceptors that innervate deep cephalic tissues. A large body of evidence supports the view that some types of headaches originate intracranially, from activation of sensory neurons that innervate the cranial meninges. However, the notion of an extracranial origin of headaches continues to be entertained, although the identity of deep extracranial cephalic tissues that might contribute to headaches remains elusive. ⋯ In behavioral studies, inflammatory stimulation of these afferents promoted periorbital tactile hypersensitivity, a sensory change linked to primary headaches. Activation and sensitization of calvarial periosteal afferents could play a role in mediating primary headaches of extracranial and perhaps also intracranial origin, as well as secondary headaches such as postcraniotomy and posttraumatic headaches. Targeting calvarial periosteal afferents may be effective in ameliorating these headaches.
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Randomized Controlled Trial
Impact of Prenatal Education on Maternal Utilization of Analgesic Interventions at Future Infant Vaccinations: A Cluster Randomized Trial.
Analgesic interventions are not routinely used during vaccine injections in infants. Parents report a desire to mitigate injection pain, but lack the knowledge about how to do so. The objective of this cluster-randomized trial was to evaluate the effect of a parent-directed prenatal education teaching module about vaccination pain management on analgesic utilization at future infant vaccinations. ⋯ Inclusion of a pain management module in prenatal classes led to increased utilization of evidence-based pain management interventions by parents at the 2-month infant vaccination appointment. Educating parents offers a novel and effective way of improving the quality of pain care delivered to infants during vaccination. Additional research is needed to determine if utilization can be bolstered further using techniques such as postnatal hospital reinforcement, reminder cards, and clinician education.