Central post-stroke pain: advances in clinical and preclinical research.

Central poststroke pain (CPSP) is a medical complication that arises poststroke and significantly impacts the quality of life and social functioning of affected individuals. Despite ongoing research, the exact pathomechanisms of CPSP remain unclear, and practical treatments are still unavailable. Our review aims to systematically analyse current clinical and preclinical studies on CPSP, which is critical for identifying gaps in knowledge and guiding the development of effective therapies. The review will clarify the clinical characteristics, evaluation scales and contemporary therapeutic approaches for CPSP based on clinical investigations. It will particularly emphasise the CPSP model initiated by stroke, shedding light on its underlying mechanisms and evaluating treatments validated in preclinical studies. Furthermore, the review will not only highlight methodological limitations in animal trials but also offer specific recommendations to researchers to improve the quality of future investigations and guide the development of effective therapies. This review is expected to provide valuable insights into the current knowledge regarding CPSP and can serve as a guide for future research and clinical practice. The review will contribute to the scientific understanding of CPSP and help develop effective clinical interventions.

Low level laser therapy alleviates mechanical allodynia in a postoperative and neuropathic pain model and alters the levels of inflammatory factors in rats.

Background: This study aimed to investigate the analgesic and preventive effect of low-level laser therapy (LLLT) on the incisional pain model and spinal nerve ligation (SNL) model in rats and identify the possible mechanisms of action. Methods: Male Sprague-Dawley rats were used, divided into different treatment groups. The single application group received LLLT before or after skin incision or SNL. The consecutive application group received LLLT for six consecutive days post-incision, three days pre-incision, or three consecutive days pre-SNL. The control group underwent skin incision or SNL without LLLT. The von Frey test was used to quantify the pain associated with mechanical allodynia. Pro-inflammatory cytokine level and alterations in nerve growth factor (NGF) expression were measured by using ELISA and immunohistochemistry, respectively in the skin, muscle of the paw, and spinal cord dorsal horn (SCDH). Results: In the incisional pain model, LLLT showed significant analgesic and preventive effect. LLLT ameliorated SNL-induced mechanical allodynia but LLLT had no preventive effect. LLLT decreased interleukin-1ß (IL-1ß) expression levels in the skin, muscle, and SCDH and reduced the optical density of skin and spinal cord NGF in the incisional pain model. Conclusions: LLLT alleviated incisional pain and neuropathic pain caused by SNL in rats, and reduced the levels of IL-1ß and NGF in the peripheral tissue and SCDH in the incisional pain model. LLLT might be effective in patients with post-operative pain and peripheral neuropathic pain.

The pathophysiological role of endoneurial inflammatory edema in early classical Guillain-Barré syndrome.

The objective of this review was to analyze the pathophysiological role of endoneurial inflammatory edema in initial stages of classic Guillain-Barré syndrome (GBS), arbitrarily divided into very early GBS (≤ 4 days after symptom onset) and early GBS (≤ 10 days). Classic GBS, with variable degree of flaccid and areflexic tetraparesis, encompasses demyelinating and axonal forms. Initial autopsy studies in early GBS have demonstrated that endoneurial inflammatory edema of proximal nerve trunks, particularly spinal nerves, is the outstanding lesion. Variable permeability of the blood-nerve barrier dictates such lesion topography. In proximal nerve trunks possessing epi-perineurium, edema may increase the endoneurial fluid pressure causing ischemic changes. Critical analysis the first pathological description of the axonal form GBS shows a combination of axonal degeneration and demyelination in spinal roots, and pure Wallerian-like degeneration in peripheral nerve trunks. This case might be reclassified as demyelinating GBS with secondary axonal degeneration. Both in acute motor axonal neuropathy and acute motor-sensory axonal neuropathy, Wallerian-like degeneration of motor fibers predominates in the distal part of ventral spinal roots abutting the dura mater, another feature re-emphasizing the pathogenic relevance of this area. Electrophysiological and imaging studies also point to a predominant alteration at the spinal nerve level, which is a hotspot in any early GBS subtype. Serum biomarkers of axonal damage, including neurofilament light chain and peripherin, are increased in the great majority of patients with any early GBS subtype; endoneurial ischemia of proximal nerve trunks could contribute to such axonal damage. It is concluded that inflammatory edema of proximal nerve trunks is an essential pathogenic event in early GBS, which has a tangible impact for accurate approach to the disease.

Comparison of international medical costs for interventional pain treatment: a focus on Korea and Japan.

Background: The rise in national health care costs has emerged as a global problem given the ever-aging population and rapid development of medical technology. The utilization of interventional pain management has, similarly, shown a continued rise worldwide. This study evaluates the differences in the medical costs in the field of interventional pain treatment (IPT) between two countries: Korea and Japan. Methods: Korean medical insurance costs for 2019 related to pain management focused on IPT were compared to those of Japan. Purchasing power parity (PPP) was used to adjust the exchange rate differences and to compare prices in consideration of the respective societies' economic power. Results: The cost of trigger point injections in Japan was 1.06 times higher than that of Korea, whereas the perineural and intraarticular injection prices were lower in Japan. The cost of epidural blocks was higher in Japan compared to Korea in both cervical/thoracic and lumbar regions. As for blocks of peripheral branches of spinal nerves, the cost of scapular nerve blocks in Japan was lower than that in Korea, given a PPP ratio 0.09. For nerve blocks in which fluoroscopy guidance is mandatory, the costs of epidurography in Japan were greater than those in Korea, given a PPP ratio 1.04. Conclusions: This is the first comparative study focusing on the medical costs related to IPT between Korea and Japan, which reveals that the costs differed along various categories. Further comparisons reflecting more diverse countries and socio-economic aspects will be required.

Software educativo como herramienta para el aprendizaje de plexos nerviosos somáticos en estudiantes de medicina

Introducción: Las características morfofuncionales de los plexos nerviosos somáticos resulta imprescindible para entender las principales lesiones de estos y la realización del examen físico, por ello este tema se estudia en todas las especialidades de las Ciencias de la Salud. Objetivo: Elaborar un software educativo que facilite el aprendizaje de las características morfofuncionales de los plexos nerviosos somáticos. Métodos: Se realizó una innovación tecnológica para elaborar un software educativo referido a los plexos nerviosos somáticos, dirigido a estudiantes del primer año de medicina. La investigación se desarrolló de septiembre 2021 a febrero 2022, se utilizó el programa CrheaSoft versión 3.1, el software Adobe PhotoShop CS4 para el procesamiento de imágenes y la suite ofimática Microsoft Office 2003 para la elaboración de textos. Resultados: El software quedó estructurado en seis módulos: inicio, temario, juegos, ejercicios, mediateca, complemento y créditos-ayuda, que muestran la información recopilada del tema y permiten la interacción con los estudiantes en todas las actividades docentes en las que se puede utilizar el producto. En la validación por criterio de expertos y de usuario, todos los aspectos fueron evaluados en la categoría de excelente y bien. Conclusiones: La creación de este software educativo constituye una vía para que el estudiante tenga acceso a la información actualizada y científica, organizada sobre las características morfofuncionales de los plexos nerviosos somáticos, que facilite la asimilación de estos contenidos en una etapa en que se han producido cambios en los escenarios docentes y en los planes de estudio de las carreras de las Ciencias de la Salud.

Introduction: Morphological characteristics of the somatic nervous plexuses result very important to understand the main injuries of them and to do the physical examination, that's why this topic is studied in all the specialties of the Health Sciences. Objective: To elaborate an educational software that facilitates the learning process of the characteristic of the somatic nervous plexuses. Methods: A technological innovation to elaborate an educational software related to somatic nervous plexuses for the first year medical students was done. The investigation was performed from September 2021 to February 2021. It was used CrheaSoft program, version 3.1, the software Adobe PhotoShop CS4 to process the imagining and the suite Office 2003 for text writing. Results: The software was structured in six modules: presentation, contents, games, exercises, anatomical images, complements and credits-help, which shows the organized information by contents and the interactions with the students in all the teaching activities where this product could be used. In the validation by expert and user criteria, all the aspects of the software were evaluated in the category of excellent and good. Conclusions: The creation of this educational software constitute a way for the students to get access to the scientific, very well organized and updated information about morphological characteristics of the somatic nervous plexuses, that facilitate the assimilation of this topics at the present where important changes has taken place at the medical schools and the study plans of Health Sciences degrees.

Assessment of an Ultrasound-Guided Rectus Sheath Block in Foals: A Cadaveric Study.

In neonatal equines, pathologies involving umbilical structures are an important cause of morbidity, and surgical removal of urachal remnants is a common procedure in clinical practice. Surgery involving the ventral abdominal wall can cause substantial pain, leading to complications and prolonged recovery. The objectives of this study were to describe a two-point bilateral ultrasound-guided rectus sheath block at the level of the umbilicus and to evaluate the extent of dye distribution in foal cadavers. Ten foal cadavers were included in the study, in which a bilateral two-point ultrasound-guided rectus sheath block was performed-one injection 5 cm cranially and a second one 5 cm caudally to the umbilicus. The injectate consisted of a mixture of iodinated contrast medium and blue dye at a volume of 0.25 mL kg-1 per injection point (total 1 mL kg-1). After the injection, computer tomography and subsequent dissection of the ventral abdominal wall were performed. The extension of the contrast medium, the number of stained nerves, and contamination of the abdominal cavity were evaluated. The cranio-caudal extension of the contrast ranged from 0.8 to 1.4 cm per milliliter of injectate. The most commonly stained ventral branches of spinal nerves were thoracic (Th) nerves 16, 17, and 18 (95%, 85%, and 80% of the nerves, respectively). Abdominal contamination was found in four animals. The results suggest that the block could provide periumbilical analgesia. Further studies with different volumes of injectate and living animals are warranted.

Thoracolumbar fascia in the lumbar region: anatomical description and topographical relationships to the cutaneous nerves: a preliminary study.

BACKGROUND: The study aims to determine principal topographical relations between thoracolumbar fascia (TLF) and lateral branches derived from the dorsal (posterior) rami of lumbar spinal nerves and elucidate their potential link to lumbar region pain. The research protocol involves basic TLF morphological description, evaluating its relation to the nerves, and examining general histology. MATERIALS AND METHODS: The research was conducted on four male cadavers fixed in 10% neutral buffered formalin. RESULTS: The dorsal rami of the spinal nerves branched into medial and lateral divisions. The lateral divisions were about 1 mm thick and mainly visible in the subcutaneous tissue during stratigraphic dissection. They pierced the TLF superficial layer. They descended sidewards and downwards within the superficial fascia (laterally to the erector spinae muscle) to provide sensory innervation to the skin. CONCLUSIONS: Anatomical relationships between TLF, deep (intrinsic or true) back muscles, and dorsal rami of the spinal nerves are complex and may be clinically involved in low back pain etiopathogenesis.

Description of an Ultrasound-Guided Erector Spinae Plane Block and Comparison to a Blind Proximal Paravertebral Nerve Block in Cows: A Cadaveric Study.

The proximal paravertebral nerve block is commonly used to provide anaesthesia to the flank during standing surgical procedures in adult cattle. It has been reported that additional anaesthetic infiltration may be necessary to provide complete anaesthesia. In humans as well as animal species, another technique-the ultrasound (US)-guided erector spinae plane block (ESPB)-has been described. The goal of the present study was to develop and investigate an US-guided ESPB in comparison to a blind proximal paravertebral nerve block (PPNB) in cow cadavers. In 10 cadaver specimens, injections of methylene blue-lidocaine (1:1) were performed at the level of T13, L1 and L2 vertebras, on one side doing an ESPB block and, on the other side, a PPNB. Five cadavers were injected with high (40 mL per injection for PPNB and 20 mL for ESPB) and five with low (20 and 15 mL, respectively) volumes of injectate. For the ESPB, the ultrasound probe was oriented craniocaudally, and the ventral-cranial aspect of the articular processes (T13, L1 and L2) was targeted for injection. The dye spreading was evaluated by dissection. The landmarks for US-guided injection were easily visualized; however, injections were accidentally performed at T12, T13 and L1. Nevertheless, L2 was stained in 60% of ESPBs. Epidural spreading was observed with both techniques and all volumes. Viscera puncture was reported in two PPNBs. The ESPB resulted in similar nerve staining compared to the PPNB while using a lower volume of injectate. Even better staining is expected with a T13-L2 instead of a T12-L1 ESPB approach. Further studies are warranted to evaluate the clinical efficacy.

Benign Peripheral Non-cranial Nerve Sheath Tumors of the Neck.

Benign peripheral non-cranial nerve sheath tumors are rare lesions, including both schwannomas and neurofibromas. These tumors arise from Schwann cells, and may originate from any peripheral, cranial, or autonomic nerve. Most of them are localized and sporadic but multifocal systemic forms can occur. Cervical sympathetic chain, brachial plexus, cervical plexus and spinal roots and nerves are the major nerve systems commonly affected. Dumbbell-shaped intra- and extradural tumors occur most commonly in the cervical spine, as well as purely extradural and paravertebral tumors. The management of these tumors has improved greatly owing to the developments in imaging techniques and surgical innovations such as endoscopically assisted approaches and robotic surgery. Microsurgical intracapsular excision of the tumor helped by the use of intraoperative fluorescent dyes and intraoperative neurophysiological monitoring minimize postoperative neural deficit, since most schwannomas are encapsulated. Most tumors can be removed with a low rate of complications and recurrence. Radiotherapy should be considered for growing lesions that are not amenable to surgery. In asymptomatic patients, observation and serial scans is an option for elderly infirm patients.

The clinical value analysis of MRN on diagnosis and treatment of lumbosacral nerve injury associated with sacral fractures / 中华骨科杂志

Objective:To discuss the clinical value of magnetic resonance neurography (MRN) on diagnosis and treatment of lumbosacral nerve injury associated with sacral fractures and analyze the characters of nerve injury which was caused by sacral fractures.Methods:The clinical data of 40 patients who had lumbosacral nerve injury associated with sacral fractures and accepted treatment in Tianjin hospital from August 2018 to December 2020 were collected based on inclusion and exclusion criteria. Twenty-four patients had unilateral sacral fractures (Tile C1) which included 16 Denis II type fractures and 8 Denis III type fractures. Sixteen patients had bilateral sacral fractures which were all Tile C3, U shaped and Denis II type sacral fractures. All patients had symptoms or signs of lumbosacral nerve injury, and accepted contrast-enhanced three-dimensional magnetic resonance neurography (CE-3D MRN) to diagnose the injury part and severity degree. The L 5-S 4 nerves were separated to three parts based on injured side and intraspinal type (IS), intraforaminal type (IF) and extraforaminal type (EF) location, and were judged the mild, medium or severe degree of nerve injury severity. Overall and pairwise Chi-square test was performed on the number of nerve injuries. Eleven patients accepted the operation of nerve dissection and exploration. The nerve injury part and severity were recorded under direct vision, and were statistically analyzed with CE-3D MRN outcome. Results:The outcome of 239 lumbosacral nerve injuries which had different part and severity were found by MRN, and all combined with sacral fractures of the same side. The nerves which ranked from largest to fewest according to injured numbers were L 5, S 1, S 2, S 3 and S 4. The statistical analysis showed that there were significant differences of injured nerve numbers except between S 1 and S 2, S 3 and S 4, and there were no significant difference of nerve injury part and severity degree between the direct visual judgement intraoperatively and preoperative CE-3D MRN examination. Conclusion:MRN can reveal the part and severity degree of lumbosacral nerve injury associated with sacral fracture clearly and accurately, which has important clinical value and should become the preferred examination of such injuries. The lumbosacral nerve injury has the most frequent features of S 1 and S 2, followed by L 5, and the least in S 3 and S 4.