The phenomenon of migration of nociogenic structures in the human sensor-algic system (results of clinical and neurophysiological studies and morphological experiments)

From the informational and structural point of view, the chronicity of pain is associated with the migration of nociogenic zones. The phenomenon of migration is based on the mechanisms of neuroplasticity, compensatory-restorative processes in the nervous system. On the basis of the phenomenon of migration of the nociogenic zone, a system of regional integrative therapy of chronic pain syndrome has been developed. Recommendations on the advisability of invasive shutdown of the nociogenic zone using invasive pharmacotherapy or surgical denervation have been proposed. In the course of studying the characteristics of chronic pain, depending on the duration of the disease, a direct proportional correlation was revealed between the increase in the components of pain and the duration of the pain syndrome, which can be explained by the increase in the number of nociogenic structures that form the complexity and stability of the pain syndrome. Thus, the necessity of neurodestructive interventions increases for attaining positive results. An important area of therapy is the inclusion of psychotherapy, pharmacotherapy and neuromodulation into the system of regional-integrative influence.

Pain Pathways and Pain Physiology

Pain is a multidimensional sensory experience that is mediated by complex peripheral and central neuroanatomical pathways and mechanisms. Typically, noxious stimuli activate specific peripheral nerve terminals onto Aδ‎ and C nerve fibers that convey pain and generate signals that are relayed and processed in the spinal cord and then conveyed via the spinothalamic tracts to the contralateral thalamus and from there to the brain. Acute pain is self-limited and resolves with the healing process, but conditions of extensive injury or inflammation sensitize the pain pathways and generate aberrant, augmented responses. Peripheral and central sensitization of neurons (as a result of spatially and temporally excessive inflammation or intense afferent signal traffic) may result in hyperexcitability and chronicity of pain, with spontaneous pain and abnormal evoked responses to stimuli (allodynia, hyperalgesia). Finally, neuropathic pain follows injury or disease to nerves as a result of hyperexcitability augmented by various sensitizing mechanisms.

Evaluation of Knee Pain in Athletes: A Radiologist's Perspective

Lower limb injuries account for most of all injuries suffered by athletes and the knee joint accounts for over half of these. The etiology of knee pain is multifactorial; a good history focusing on the mechanism of injury and the chronicity of pain is extremely useful in correlating with radiologic findings and establishing a clinically meaningful diagnosis. This review article will discuss several important and common causes of acute and chronic knee pain in athletes, focusing on their mechanism of injury and site of pain as well as their salient imaging findings.