Characteristics of neuropathic pain in individuals with chronic spinal cord injury

Long-term outcome and predictors of neurological recovery in cervical spinal cord injury: a population-based cohort study

This retrospective study analyzed prognostic factors for neurological improvement and ambulation in 194 adult patients (≥ 15 years) with traumatic cervical spinal cord injuries treated at the neurological SCI unit (SCIU) at the Karolinska University Hospital Stockholm, Sweden, between 2010 and 2020. The primary outcome was American spinal injury association impairment scale (AIS) improvement, with secondary focus on ambulation restoration. Results showed 41% experienced AIS improvement, with 51% regaining ambulation over a median follow-up of 3.7 years. Significant AIS improvement (p < 0.001) and reduced bladder/bowel dysfunction (p < 0.001) were noted. Multivariable analysis identified initial AIS C-D (< 0.001), central cord syndrome (p = 0.016), and C0-C3 injury (p = 0.017) as positive AIS improvement predictors, while lower extremity motor score (LEMS) (p < 0.001) and longer ICU stays (p < 0.001) were negative predictors. Patients with initial AIS C-D (p < 0.001) and higher LEMS (p < 0.001) were more likely to regain ambulation. Finally, older age was a negative prognostic factor (p = 0.003). In conclusion, initial injury severity significantly predicted neurological improvement and ambulation. Recovery was observed even in severe cases, emphasizing the importance of tailored rehabilitation for improved outcomes.

Post-discharge follow-up of patients with spine trauma in the National Spinal Cord Injury Registry of Iran during the COVID-19 pandemic: Challenges and lessons learned

PURPOSE

The purpose of the National Spinal Cord Injury Registry of Iran (NSCIR-IR) is to create an infrastructure to assess the quality of care for spine trauma and in this study, we aim to investigate whether the NSCIR-IR successfully provides necessary post-discharge follow-up data for these patients.

METHODS

An observational prospective study was conducted from April 11, 2021 to April 22, 2022 in 8 centers enrolled in NSCIR-IR, respectively Arak, Rasht, Urmia, Shahroud, Yazd, Kashan, Tabriz, and Tehran. Patients were classified into 3 groups based on their need for care resources, respectively: (1) non-spinal cord injury (SCI) patients without surgery (group 1), (2) non-SCI patients with surgery (group 2), and (3) SCI patients (group 3). The assessment tool was a self-designed questionnaire to evaluate the care quality in 3 phases: pre-hospital, in-hospital, and post-hospital. The data from the first 2 phases were collected through the registry. The post-hospital data were collected by conducting follow-up assessments. Telephone follow-ups were conducted for groups 1 and 2 (non-SCI patients), while group 3 (SCI patients) had a face-to-face visit. This study took place during the COVID-19 pandemic. Data on age and time interval from injury to follow-up were expressed as mean ± standard deviation (SD) and response rate and follow-up loss as a percentage.

RESULTS

Altogether 1538 telephone follow-up records related to 1292 patients were registered in the NSCIR-IR. Of the total calls, 918 (71.05%) were related to successful follow-ups, but 38 cases died and thus were excluded from data analysis. In the end, post-hospital data from 880 patients alive were gathered. The success rate of follow-ups by telephone for groups 1 and 2 was 73.38% and 67.05% respectively, compared to 66.67% by face-to-face visits for group 3, which was very hard during the COVID-19 pandemic. The data completion rate after discharge ranged from 48% - 100%, 22% - 100% and 29% - 100% for groups 1 - 3.

CONCLUSIONS

To improve patient accessibility, NSCIR-IR should take measures during data gathering to increase the accuracy of registered contact information. Regarding the loss to follow-ups of SCI patients, NSCIR-IR should find strategies for remote assessment or motivate them to participate in follow-ups through, for example, providing transportation facilities or financial support.

P2Y12 receptor involved in the development of chronic nociceptive pain as a sensory information mediator

Direct or indirect damage to the nervous system (such as inflammation or tumor invasion) can lead to dysfunction and pain. The generation of pain is mainly reflected in the activation of glial cells and the abnormal discharge of sensory neurons, which transmit stronger sensory information to the center. P2Y12 receptor plays important roles in physiological and pathophysiological processes including inflammation and pain. P2Y12 receptor involved in the occurrence of pain as a sensory information mediator, which enhances the activation of microglia and the synaptic plasticity of primary sensory neurons, and reaches the higher center through the ascending conduction pathway (mainly spinothalamic tract) to produce pain. While the application of P2Y12 receptor antagonists (PBS-0739, AR-C69931MX and MRS2359) have better antagonistic activity and produce analgesic pharmacological properties. Therefore, in this article, we discussed the role of the P2Y12 receptor in different chronic pains and its use as a pharmacological target for pain relief.

Neuronal P2X4 receptor may contribute to peripheral inflammatory pain in rat spinal dorsal horn

Objective

Intense inflammation may result in pain, which manifests as spinal central sensitization. There is growing evidence that purinergic signaling plays a pivotal role in the orchestration of pain processing. Over the last decade the ionotropic P2X purino receptor 4 (P2X4) got into spotlight in neuropathic disorders, however its precise spinal expression was scantily characterized during inflammatory pain. Thus, we intended to analyze the receptor distribution within spinal dorsal horn and lumbar dorsal root ganglia (DRG) of rats suffering in inflammatory pain induced by complete Freund adjuvant (CFA).

Methods

CFA-induced peripheral inflammation was validated by mechanical and thermal behavioral tests. In order to ensure about the putative alteration of spinal P2X4 receptor gene expression qPCR reactions were designed, followed by immunoperoxidase and Western blot experiments to assess changes at a protein level. Colocalization of P2X4 with neuronal and glial markers was investigated by double immunofluorescent labelings, which were subsequently analyzed with IMARIS software. Transmission electronmicroscopy was applied to study the ultrastructural localization of the receptor. Concurrently, in lumbar DRG cells similar methodology has been carried out to complete our observations.

Results

The figures of mechanical and thermal behavioral tests proved the establishment of CFA-induced inflammatory pain. We observed significant enhancement of P2X4 transcript level within the spinal dorsal horn 3 days upon CFA administration. Elevation of P2X4 immunoreactivity within Rexed lamina I-II of the spinal gray matter was synchronous with mRNA expression, and confirmed by protein blotting. According to IMARIS analysis the robust protein increase was mainly detected on primary afferent axonterminals and GFAP-labelled astrocyte membrane compartments, but not on postsynaptic dendrites was also validated ultrastructurally within the spinal dorsal horn. Furthermore, lumbar DRG analysis demonstrated that peptidergic and non-peptidergic nociceptive subsets of ganglia cells were also abundantly positive for P2X4 receptor in CFA model.

Conclusion

Here we provide novel evidence about involvement of neuronal and glial P2X4 receptor in the establishment of inflammatory pain.

The Efficacy of Sphenopalatine Ganglion Block and Radiofrequency Denervation in the Treatment of Cluster Headache: A Case Series

Background

Cluster headache is a variant of primary neurovascular headaches. some patients with cluster headache are not responsive to medical treatment and may benefit from interventional modalities, including sphenopalatine ganglion block and denervation.

Objectives

Our purpose was to evaluate the efficacy of sphenopalatine ganglion block/denervation in the treatment of cluster headache.

Methods

In this study, we performed the sphenopalatine ganglion block for patients with cluster headaches, intractable to medical therapy, who were referred to our pain clinic between 2014 and 2018. We registered the following information for all patients: demographic data, pain relief, and pain intensity. First, we conducted a prognostic C-arm-guided sphenopalatine ganglion block. If there was at least 50% pain relief within the first 5 h, then we denervated the ganglion by radiofrequency ablation. The main outcome of the study (dependent variable) was pain relief. We followed the patients for 6 months.

Results

Among 23 enrolled patients, 19 consented to interventional treatment. Fifteen out of 19 patients (79%) had an acceptable response to the prognostic block. Ultimately, 11 patients underwent ganglion denervation, and 4 patients did not consent for ganglion ablation. Pain relief at intervals of 48 h, and 1, 3, and 6 months after ganglion denervation was 77, 59, 50, and 31 percent, respectively.

Conclusions

Sphenopalatine ganglion conventional radiofrequency denervation can effectively decrease the pain intensity of the patients with cluster headache for at least several months.

The role of P2X4 receptors in chronic pain: A potential pharmacological target

Chronic pain is a common symptom of most clinical diseases, which seriously affects the psychosomatic health of patients and brings some pain to patients. Due to its pathological mechanism is very complicated and the treatment of chronic pain has always been a difficult problem in clinical. Normally, drugs are usually used to relieve pain, but the analgesic effect is not good, especially for cancer pain patients, the analgesic effect is poor. Therefore, exploring the pathogenesis and treatment of chronic pain has aroused the interest of many researchers. A large number of studies have shown that the role of ATP and P2X4 receptor (P2X4R) play an important role in the pathogenesis of chronic pain. P2X4R is dependent on ATP ligand-gated ion channel receptor, which can be activated by ATP and plays an important role in the information transmission of nerve system and the formation of pain. Therefore, in this paper, we comprehensively described the structure and biological functions of P2X4R, and outlined behavioral evaluation methods of chronic pain models. Moreover, we also explored the inherent relationship between P2X4R and chronic pain, and described the therapeutic effect of P2X4R antagonist on chronic pain, and provided some valuable help for the treatment of chronic pain.

The role of P2X4 receptor in neuropathic pain and its pharmacological properties

Neuropathic pain (NPP) is a common symptom of most diseases in clinic, which seriously affects the mental health of patients and brings certain pain to patients. Due to its pathological mechanism is very complicated, and thus, its treatment has been one of the challenges in the field of medicine. Therefore, exploring the pathogenesis and treatment approach of NPP has aroused the interest of many researchers. ATP is an important energy information substance, which participates in the signal transmission in the body. The P2 × 4 receptor (P2 × 4R) is dependent on ATP ligand-gated cationic channel receptor, which can be activated by ATP and plays an important role in the transmission of information in the nervous system and the formation of pain. In this paper, we provide a comprehensive review of the structure and function of the P2 × 4R gene. We also discuss the pathogenesis of NPP and the intrinsic relationship between P2 × 4R and NPP. Moreover, we explore the pharmacological properties of P2 × 4R antagonists or inhibitors used as targeted therapies for NPP.

The Influence of Chronic Pain on Number Sense and Numeric Rating Scale: A prospective Cohort Study

Background

Several studies have demonstrated an association between chronic pain and impairment of cognitive capabilities. Since the number sense is one of the cognitive ability involved in the evaluation of pain intensity using some pain measurement tools, impairment of number sense may impact pain assessment. Therefore, the validity of number-based pain assessment tools should be re-evaluated.

Objectives

This study aimed to determine whether number sense is altered in chronic and acute pain patients compared to healthy subjects.

Methods

Overall, 150 participants were recruited and divided into the three groups of controls, chronic and acute pain patients. Pain intensity was evaluated using numeric and verbal rating scales as pain assessment tools. Number sense was assessed using number naming, number marking, and line bisection tasks. Deviation from correct answers was measured for each task.

Results

Patients with chronic pain (migraine headache) had higher pain intensity scores than acute pain subjects. Chronic pain patients showed significant deviation from the expected responses compared to controls in the line bisection task.

Conclusions

Chronic pain patients may have impaired number sense and may differently use number-based pain assessment tools in comparison with healthy individuals.