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Myofascial Trigger Points, Sensitization, and Chronic Musculoskeletal Pain
Published in Sahar Swidan, Matthew Bennett, Advanced Therapeutics in Pain Medicine, 2020
Vy Phan, Jay P. Shah, Pamela Stratton
In addition to influencing the limbic system, negative affect and hormonal fluctuations may then modulate the periaqueductal gray (PAG) in the midbrain and influence the rostral ventral medulla (RVM), contributing to maladaptive neuroplastic changes and neurogenic inflammation (Figure 11.3). The RVM, a relay area between the PAG and the spinal dorsal horn, contains a population of ON cells, which can increase pain perception, and OFF cells, which can decrease pain perception. These ON/OFF cells are part of the descending inhibitory pain system. Following initial tissue injury, the ON cells serve a useful and protective purpose to prevent further damage. Under ordinary circumstances, tissue healing would lead to a decrease in ON cell activity and an increase in OFF cell activity.13 However, in chronic musculoskeletal pain conditions, there appears to be a shift to a decrease in inhibition, presumably due to an imbalance of ON cell and OFF cell activity.27 Thus, over time, maladaptive neuroplastic changes may result in disinhibition in the spinal dorsal horn. As a result, dorsal root reflexes can create a neurogenic inflammation, which then leads to local tissue tenderness, even in the absence of ongoing tissue injury or nociception.
Spinal Cord and Reflexes
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The sensory fibers that enter the spinal cord through the dorsal roots are part of what are referred to as the first-order neurons in the pathway from the periphery to the cerebral cortex. As mentioned before, the cell bodies of these first-order neurons are in the dorsal root ganglia. The dorsal column–medial lemniscus pathway (DCML), also known as the posterior column-medial lemniscus pathway (PCML), contains first-order afferents that convey sensations of fine touch, vibration, and proprioception. The pathway is divided into two components: (i) the gracile fasciculus that carries information from the lower limb, below T6, and terminates in the gracile nuclei in the medulla (Figure 12.17), and (ii) the cuneate fasciculus that carries information from the upper limb, above T6, and terminates in the cuneate nuclei in the medulla. The neurons of the gracile and cuneate nuclei are second-order neurons in the pathway from the periphery to the cerebral cortex. Their axons decussate at the level of the medulla, travel up the brainstem as the medial lemniscus on the contralateral side, and terminate in the thalamus, which relays the signals to the cerebral cortex.
The nervous system
Published in Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella, Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella
The dorsal root contains afferent, or sensory, neurons. Impulses in these neurons travel from peripheral tissues toward the spinal cord. The dorsal root joins the spinal cord laterally, toward the posterior surface of the cord (Figure 13.5). The ventral root contains efferent, or motor, neurons. Impulses in these neurons travel away from the spinal cord toward the peripheral tissues. The ventral root exits the spinal cord laterally, toward the anterior surface of the cord.
Association between subarachnoid hemorrhage-induced hydrocephalus and hydromyelia: pathophysiological changes developed in an experimental model
Published in Neurological Research, 2023
A ‘craniospinal pressure dissociation’ theory was postulated by Williams [6]. This theory posited that significant pressure changes during daily activities may increase the intrathoracic pressure, as reflected in the spinal CSF through the epidural spinal veins [6]. The CSF flow from the cranial to the SAS reflects expansile brain motion during the cardiac cycle, especially in the arterial pulse. A syrinx cavity is frequently accompanied by a myelomalacia area. The progression of a syrinx cavity transmits the pressure to the medulla spinalis surface. The syrinx does not require communication between the central channel and the ventricular system. The dorsal root entry zone and the perivascular spaces can influence the communication between the central channel and extracellular spaces of the medulla spinalis. This mechanism can play a primary role in compensating for the changes occurring in the perimedullary CSF flow. However, pathologies and iatrogenic conditions, such as spinal meningitis, SAH, peridural anesthesia, intramedullary spinal surgery, infarction, trauma, and spinal injuries, frequently cause arachnoid scarring that impaired this mechanism [24,25]. Both parenchymal (extracanalicular) syringes and paracentral dissections of central channel syringes are lined with glial or fibroglial tissues that are frequently ruptured into the SAS. The fibroglial tissue is characterized by Wallerian degeneration, neuronophagia, and central chromatolysis. The clinical presentation in patients varies depending on the affected tracts and nuclei with this cavity [2,24,25].
How effective is a multimodal physical rehabilitation protocol in patients advised surgery for chronic lumbar radicular pain? A retrospective analysis of 189 patients with a minimum follow-up of 1 year
Published in European Journal of Physiotherapy, 2022
Sara Ansari, Gautam M. Shetty, Garima Anandani, C. S. Ram
Low back pain (LBP) is now the number one cause of disability globally with increasing annual health care and social costs due to lost wages and decreased productivity [1–3]. The role of interventional therapies and surgery is limited in the treatment of chronic LBP. The benefits of surgical procedures such as fusion surgery for non-radicular discogenic LBP may be modestly greater than non-surgical treatment options such as intensive rehabilitation [4–6]. Furthermore, surgery has a greater risk of adverse events and more expensive compared to non-surgical options [5]. Surgical procedures are primarily recommended for chronic lumbar radicular pain (LRP) [4–6], where pain is observed in the lower extremities along the course (dermatome) of a spinal nerve root with or without associated LBP and is caused by irritation or inflammation of sensory root or the dorsal root ganglion (DRG) of a lumbosacral spinal nerve [7,8].
Roles of CaMKIIβ in the neurotoxicity induced by ropivacaine hydrochloride in dorsal root ganglion
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Xianjie Wen, Yiqun Li, Xingqing Liu, Can Sun, Jinbing Lin, Wenli Zhang, Yabin Wu, Xiaoping Wang
The protocols for the animal use were approved by the Ethics Committee of Affiliated Foshan Hospital of the Southern medical University. One-day-old SD rats (Animal Laboratory Center, the Southern Medical University of China) were anaesthetized with ketamine. Spinal cord and dorsal root ganglia were exposed. Dorsal root ganglia were separated from the intervertebral foramen. After separation, dorsal root ganglia were moved into 15 ml centrifugal tube for digestion with 0.125% trypsin at 37 °C for 20 min. After digestion, the dorsal root ganglia were added to neurobasal medium (containing 4.5 g/L-glucose, 2 mmol/L-glutamine, 1% FBS, 20 ml/L-27 additive, 10 μg/ml NGF, penicillin 100 U/ml, streptomycin 100 μg/ml) and filtered by 400 mesh stainless steel mesh. The cell suspension was inoculated into the cell culture plate. The cell density was 1–2 × 105/ml. After 48 h of incubation at 37 °C and 5% CO2 incubator, the cell culture medium was replaced and 5 mM cytarabine was added to inhibit the proliferation of non-neuron cells. After 96 h, the cell suspension was replaced by cytarabin-free culture medium. The medium was changed every 3 days.