Population Imaging of Central Sensitization

Capsaicin applied locally to the skin causes central sensitization that results in allodynia, a state in which pain is elicited by innocuous stimuli. Here, we used two-photon calcium imaging of neurons in the dorsal spinal cord to visualize central sensitization across excitatory interneurons and spinal projection neurons. To distinguish among excitatory neuron subtypes, we developed CICADA, a cell profiling approach that leverages the expression of distinct Gq-coupled receptors. We then identified capsaicin-responsive and capsaicin-sensitized neuronal populations. Capsaicin-sensitized neurons showed emergent responses to low threshold input and increased receptive field sizes consistent with the psychophysical phenomenon that allodynia is observed across an extended secondary zone. Finally, we identified spinal projection neurons that showed a shift in tuning toward low threshold input. These experiments provide a population-level view of central sensitization and a framework with which to model somatosensory integration in the dorsal horn.

C6 nerve root palsy after double-door cervical laminoplasty

Background: This study correlated the relationship between postoperative C6 nerve root palsies and various patient-related clinical, radiographic, and surgical parameters. Methods: The medical records of 318 patients undergoing double-door cervical laminoplasty for myelopathy were reviewed. Twelve (3.8%) had postoperative C6 nerve root palsies. Their clinical, radiographic, and surgical procedures were analyzed looking for a correlation/explanation for these new C6 root deficits. Results: The following factors correlated with patients’ developing new postoperative C6 nerve root deficit following double-door cervical laminoplasty; a high correlation with additional C5 palsies, narrower C6 intervertebral foraminal widths, greater anterior protrusions of the C6 articular process, and larger posterior shifts of the spinal cord on magnetic resonance (MR) between the C4/C5-C6/C7 levels. Conclusion: Factors correlating with the new onset of C6 nerve root palsies following double-door cervical laminoplasty included; a high correlation with new C5 palsies, more severe foraminal stenosis, greater anterior protrusions of the C6 articular process, and more extensive dorsal spinal cord migration.

5-HT7 Receptor Is Involved in Electroacupuncture Inhibition of Chronic Pain in the Spinal Cord

Knee osteoarthritis (KOA) is a common and disabling condition characterized by attacks of pain around the joints, and it is a typical disease that develops chronic pain. Previous studies have proved that 5-HT1, 5-HT2, and 5-HT3 receptors in the spinal cord are involved in electroacupuncture (EA) analgesia. The 5-HT7 receptor plays antinociceptive role in the spinal cord. However, it is unclear whether the 5-HT7 receptor is involved in EA analgesia. The 5-HT7 receptor is a stimulatory G-protein (Gs)-coupled receptor that activates adenylyl cyclase (AC) to stimulate cyclic adenosine monophosphate (cAMP) formation, which in turn activates protein kinase A (PKA). In the present study, we found that EA significantly increased the tactile threshold and the expression of the 5-HT7 receptor in the dorsal spinal cord. Intrathecal injection of 5-HT7 receptor agonist AS-19 mimicked the analgesic effect of EA, while a selective 5-HT7 receptor antagonist reversed this effect. Moreover, intrathecal injection of AC and PKA antagonists prior to EA intervention prevented its anti-allodynic effect. In addition, GABAA receptor antagonist bicuculline administered (intrathecal, i.t.) prior to EA intervention blocked the EA effect on pain hypersensitivity. Our data suggest that the spinal 5-HT7 receptor activates GABAergic neurons through the Gs–cAMP–PKA pathway and participates in EA-mediated inhibition of chronic pain in a mouse model of KOA.

Syringomyelia after spinal anaesthesia: A case report

Lumbar spinal or epidural anaesthesia has a lower complication rate compared to general anaesthesia. An occasional patient may develop spinal cord injury during the procedure and develop neurological complications. We report an interesting case of paraparesis due to dorsal spinal cord involvement and syrinx formation following spinal anaesthesia for abdominal surgery.

Acute Transverse Myelitis Associated with COVID-19 vaccine: A Case Report

The case report demonstrates the issue of Khalid Ali, who is a citizen of Yamen, explicitly living in Saudi Arabia. He is 38 years, weighs 82kgs, and of 162 cm in height. He is a sales professional and married with two kids. Khalid Ali has been living healthy until two years ago when he started experiencing pains in his lower extremities accompanied by numbness. He was treated, and everything went back to normal until soon when the case came back after the administration of the Pfizer vaccine as a preventive measure for COVID-19 disease. The consequence of the administration of the Pfizer vaccine resulted in severe pain and weaknesses in his legs and severe headache on the second day, which resulted in him being put on an ICU after 48 hours since he was almost paralyzed. A series of tests were conducted on him, including magnetic resonance imaging (MRI), hematology, and biochemistry which involved Cerebrospinal Fluid (CSF) protein test. MRI findings were significant since they indicated acute inflammation on the spine observed on the dorsal spinal cord with contrast and lumbosacral spinal cord. All the hematology tests turned out to be expected. Biochemistry conducted tests were similarly standard except for CSF protein which was highly abnormal. The combination of the high abnormal CSF protein test and acute inflammation of the spine observed from the MRI findings were confirmed evidence of acute transverse myelitis as a result of the administration of the Pfizer vaccine.

A Rare Case of Extra Dural Dorsal Meningioma; Case Report and Analytique Review of Literature about 77 Cases

Spinal meningiomas are usually intra dural tumors, the purely extra dural localization is exceptional, they are easily mistaken for malignant tumor resulting in inadequate management. Only 77 cases have been reported in the literature. Less than 28 cases have been confirmed after durotomy since 1898. We report a new observation followed by an analytical review of the literature with a study of the socio-epidemiological, radiological parameters and of the neurosurgical and progressive management of extra dural spinal meningiomas. Observation: a 57-year-old, female patient with no medical history was admitted to our training for slow dorsal spinal cord compression progression since 06 months. Neurological examination found FRANKEL stage C paraplegia, higher level D7 hypoaesthesia without sphincter disorders. The medullary MRI objectified an intraspinal process of 1.5x2x1cm, well limited, of the right posterolateral of D8-D9 causing compression of the dorsal cord with an intramedullary hyper signal in T2. The D8-D9 laminectomy was performed. Surgical exploration found an extra dural lesion without intra dural extension. The excision was macroscopically complete. Histological examination was in favor of a benign meninigothelial. The post-operative course was marked by a partial and progressive recovery of the neurological deficit and no recurrence. Discussion: the retrospective analysis of literature about 49 publications was founded that, the incidence in 1933 by Elsberg was 5.5%, Haft in 1963 found 3.5%. In 2020 our study found 3.46% of all spine meningioma. The mean age is 44.19 years [8 years -85 years] with a female predominance of 2/1. The mode of revelation is in 11.53% of fortuitous discovery, in 59.93% by the high state of spinal cord compression stage C of FRANKEL. The topography is dorsal = 51.31%, cervical = 44.76%. MRI scan has been use since 1996 at 67.60%. Laminectomy was performed in 71.79% with durotomy in 11%. The excision is complete with SIMPSON I in 70% and SYMPSON III in 27%. The predominant histological is a grade 1 of meningioma = 73.41%, grade 2 = 6.32%, grade 3 = 1.26% in 19 % meningioma was not specified by the authors. Conclusion: The prognosis of extra dural spinal meningiomas according to our study is good overall with only 3 cases of recurrence of spinal meningioma in 36 patients, or 8.33% after a mean follow-up of 31.59 months [1 -168 months] with P=0,012.

Tlx3 Exerts Direct Control in Specifying Excitatory Over Inhibitory Neurons in the Dorsal Spinal Cord

The spinal cord dorsal horn is a major station for integration and relay of somatosensory information and comprises both excitatory and inhibitory neuronal populations. The homeobox gene Tlx3 acts as a selector gene to control the development of late-born excitatory (dILB) neurons by specifying glutamatergic transmitter fate in dorsal spinal cord. However, since Tlx3 direct transcriptional targets remain largely unknown, it remains to be uncovered how Tlx3 functions to promote excitatory cell fate. Here we combined a genomics approach based on chromatin immunoprecipitation followed by next generation sequencing (ChIP-seq) and expression profiling, with validation experiments in Tlx3 null embryos, to characterize the transcriptional program of Tlx3 in mouse embryonic dorsal spinal cord. We found most dILB neuron specific genes previously identified to be directly activated by Tlx3. Surprisingly, we found Tlx3 also directly represses many genes associated with the alternative inhibitory dILA neuronal fate. In both cases, direct targets include transcription factors and terminal differentiation genes, showing that Tlx3 directly controls cell identity at distinct levels. Our findings provide a molecular frame for the master regulatory role of Tlx3 in developing glutamatergic dILB neurons. In addition, they suggest a novel function for Tlx3 as direct repressor of GABAergic dILA identity, pointing to how generation of the two alternative cell fates being tightly coupled.