Protocol paper: kainic acid excitotoxicity-induced spinal cord injury paraplegia in Sprague-Dawley rats

BACKGROUND: Excitotoxicity-induced in vivo injury models are vital to reflect the pathophysiological features of acute spinal cord injury (SCI) in humans. The duration and concentration of chemical treatment controls the extent of neuronal cell damage. The extent of injury is explained in relation to locomotor and behavioural activity. Several SCI in vivo methods have been reported and studied extensively, particularly contusion, compression, and transection models. These models depict similar pathophysiology to that in humans but are extremely expensive (contusion) and require expertise (compression). Chemical excitotoxicity-induced SCI models are simple and easy while producing similar clinical manifestations. The kainic acid (KA) excitotoxicity model is a convenient, low-cost, and highly reproducible animal model of SCI in the laboratory. The basic impactor approximately cost between 10,000 and 20,000 USD, while the kainic acid only cost between 300 and 500 USD, which is quite cheap as compared to traditional SCI method. METHODS: In this study, 0.05 mM KA was administered at dose of 10 µL/100 g body weight, at a rate of 10 µL/min, to induce spinal injury by intra-spinal injection between the T12 and T13 thoracic vertebrae. In this protocol, detailed description of a dorsal laminectomy was explained to expose the spinal cord, following intra-spinal kainic acid administration at desired location. The dose, rate and technique to administer kainic acid were explained extensively to reflect a successful paraplegia and spinal cord injury in rats. The postoperative care and complication post injury of paraplegic laboratory animals were also explained, and necessary requirements to overcome these complications were also described to help researcher. RESULTS: This injury model produced impaired hind limb locomotor function with mild seizure. Hence this protocol will help researchers to induce spinal cord injury in laboratories at extremely low cost and also will help to determine the necessary supplies, methods for producing SCI in rats and treatments designed to mitigate post-injury impairment. CONCLUSIONS: Kainic acid intra-spinal injection at the concentration of 0.05 mM, and rate 10 µL/min, is an effective method create spinal injury in rats, however more potent concentrations of kainic acid need to be studied in order to create severe spinal injuries.

Feasibility of Ultrasound-Guided Lumbar and S1 Nerve Root Block: A Cadaver Study

OBJECTIVE: This study evaluated the feasibility of ultrasound-guided lumbar nerve root block (LNRB) and S1 nerve root block by identifying spread patterns via fluoroscopy in cadavers.METHOD: A total of 48 ultrasound-guided injections were performed in 4 fresh cadavers from L1 to S1 roots. The target point of LNRB was the midpoint between the lower border of the transverse process and the facet joint at each level. The target point of S1 nerve root block was the S1 foramen, which can be visualized between the median sacral crest and the posterior superior iliac spine, below the L5-S1 facet joint. The injection was performed via an in-plane approach under real-time axial view ultrasound guidance. Fluoroscopic validation was performed after the injection of 2 cc of contrast agent.RESULTS: The needle placements were correct in all injections. Fluoroscopy confirmed an intra-foraminal contrast spreading pattern following 41 of the 48 injections (85.4%). The other 7 injections (14.6%) yielded typical neurograms, but also resulted in extra-foraminal patterns that occurred evenly in each nerve root, including S1.CONCLUSION: Ultrasound-guided injection may be an option for the delivery of injectate into the S1 nerve root, as well as lumbar nerve root area.

Comparison of transforaminal and interlaminar epidural steroid injections for the treatment of chronic lumbar pain / Comparação das técnicas transforaminal e interlaminar de injeções epidurais de esteroides para o tratamento de dor lombar crônica

Abstract Study design: A cross-sectional study. Objective: We compared the 12 month outcomes of fluoroscopically guided transforaminal epidural steroid injections with interlaminar epidural steroid injections for the treatment of chronic lumbar spinal pain. Chronic lower back pain is a multifactorial disorder with many possible etiologies. The lifetime prevalence of spinal pain is reportedly 65-80% in the neck and lower back. Epidural injection of corticosteroids is a commonly used intervention for managing chronic spinal pain. Methods: Patients who did not benefit from previous treatments were included in this study. Injections were performed according to magnetic resonance imaging findings at the nearest level of lumbar pathology; 173 patients received interlaminar epidural steroid injections and 126 patients received transforaminal epidural steroid injections. All of the patients were regularly followed up for 12 months using a verbal numeric rating scale. Magnetic resonance imaging findings, complications, verbal numeric rating scale, and satisfaction scores were recorded. Results: Lumbar disk pathology was the most frequently encountered problem. The interlaminar epidural steroid injections were preferred at the L4-L5 intervertebral level. Verbal numeric rating scale scores significantly decreased during the 12-month period compared to basal scores (p < 0.001). Significant differences between the two groups according to verbal numeric rating scale and satisfaction scores were not observed (p > 0.05). There were no major complications; however, the interlaminar epidural steroid injections group had 22 (12.7%) minor complications, and the transforaminal epidural steroid injections group had 12 (9.5%) minor complications. Conclusions: This study showed that interlaminar epidural steroid injections can be as effective as transforaminal epidural steroid injections when performed at the nearest level of lumbar pathology using fluoroscopy in 12-month intervals.

Resumo Desenho do estudo: Estudo transversal. Objetivo: Comparamos os desfechos de 12 meses de injeções peridurais de esteroides usando a técnica transforaminal (IPETF) guiada por fluoroscopia com as injeções peridurais de esteroides usando a técnica interlaminar (IPEIL) para o tratamento da dor lombar crônica. A dor lombar crônica é uma doença multifatorial com muitas etiologias possíveis. Relata-se que a prevalência de dor na coluna durante a vida é de 65%-80% no pescoço e parte inferior das costas. A injeção peridural de corticosteroides é uma intervenção comumente usada para controlar a dor crônica da coluna vertebral. Métodos: Pacientes que não obtiveram benefício de tratamentos anteriores foram incluídos neste estudo. As injeções foram realizadas de acordo com os achados em Ressonância Magnética (RM) ao nível mais próximo da patologia lombar; 173 pacientes receberam IPEIL e 126 pacientes receberam IPETF. Todos os pacientes foram acompanhados regularmente por 12 meses, usando uma escala numérica verbal (ENV) para a classificação. Achados em RM, complicações, escores ENV e índices de satisfação foram registrados. Resultados: Patologia em disco lombar foi o problema mais frequentemente encontrado. IPEIL foi preferido ao nível intervertebral de L4-L5. Os escores da ENV diminuíram significativamente durante o período de 12 meses em comparação com os valores basais (p < 0,001). Não houve diferenças significativas entre os dois grupos de acordo com a ENV e os índices de satisfação (p > 0,05). Não houve grandes complicações, mas houve complicações menores em 22 (12,7%) no grupo IPEIL e 12 (9,5%) no grupo IPETF. Conclusões: Este estudo mostrou que IPEIL pode ser tão eficaz como IPETF quando realizadas ao nível mais próximo da patologia lombar usando a fluoroscopia em intervalos de 12 meses.

Role of NO/cGMP in the cardioprotective effects of intrathecal morphine preconditioning against myocardial ischemia-reperfusion injury in rats / 中国药理学通报

Aim To investigate the role of NO/cGMP in the cardioprotective effects of intrathecal morphine preconditioning against myocardial ischemia-reperfu-sion injury in rats. Method 54 Male Sprague-Dawley Rats were used to establish the model of intrathecal catheter placement. The rats were randomly assigned to 9 groups. SHAM (sham group), CON (control, sa-line) , ITMP ( intrathecal morphine preconditioning, 3μg·kg-1 ) , L-NAME+ITMP ( NO synthetase inhibi-tor,L-NAME ) , ODQ + ITMP ( guanylate cyclase in-hibitor, ODQ ) , KT5823 + ITMP ( PKG inhibitor, KT5823),L-NAME,ODQ,KT5823,6ratsineach group. ITMP were produced by three cycles of 5 min intrathecal injection of morphine and 5 min intermis-sion before myocardial ischemia, CON were achieved by intrathecal injection of saline in the same way, L-NAME+ITMP, ODQ +ITMP, KT5823 +ITMP were prepared by intrathecally administering L-NAME ( 30 nmol), ODQ(11 nmol) and KT5823(20 pmol) 10 minutes prior to ITMP respectively, L-NAME, ODQ, KT5823 worked as the control of inhibitors themselves respectively without ITMP. Subsequently, all rats were subjected to 30 min of left coronary artery occlusion followed by 2 h of reperfusion except the SHAM group. Myocardial infarct size, as a percentage of the AAR, was determined by 2 , 3 , 5-triphenyltetrazolium stai-ning. Results Compared with CON, the volumes of IS and IS/AAR were reduced in ITMP ( P <0.01 );the protective effects of ITMP were abolished by pre-treatment with L-NAME, ODQ and KT5823 ( P <0.01 );Conclusions NO/cGMP might be involved in the cardioprotective effect of intrathecal morphine pre-conditioning against myocardial ischemia and reperfu-sion injury in rats.

Effect of Injection Speed of Local Anesthetic on Hypotension during Spinal Anesthesia for Cesarean Section / 이화의대지

OBJECTIVES: Maternal hypotension is a common problem during cesarean section under spinal anesthesia. We evaluated the influence of injection speed of local anesthetic to subarachnoid space on maternal hypotension and level of sensory block. METHODS: Bupivacaine (0.5%) 9 mg with fentanyl 10 microg was injected to subarachnoid space either quickly (during 20 seconds, 0.1 mL/sec, n=20) or slowly (during 100 seconds, 0.02 mL/sec, n=20) in parturients scheduled for elective cesarean section. The onset and level of sensory block was checked and heart rate and blood pressure was checked by 2.5 minutes during 20 minutes. Hypotension (systolic blood pressure <100 mmHg or <70% of baseline) was treated with ephedrine. RESULTS: Hypotension occurred 70% of parturients with spinal anesthesia. Slow injection didn't influence on the onset and level of sensory block and didn't reduce the incidence of hypotension. But onset of hypotension was delayed. CONCLUSION: Slow injection (during 100 seconds, 0.02 mL/sec) of local anesthetic delayed onset of hypotension and required less amount of ephedrine. Slow injection of local anesthetic was one of the effective methods for the cardiovascular stability during cesarean section under spinal anesthesia.

Catheter Obstruction of Intrathecal Drug Administration System: A Case Report

Intrathecal drug administration system (ITDAS) can reduce the side effects while increasing the effectiveness of opioids compared to systemic opioid administration. Therefore, the use of ITDAS has increased in the management of cancer pain and chronic intractable pain. Catheter obstruction is a serious complication of ITDAS. Here, we present a case of catheter obstruction by a mass formed at the side hole and in the lumen. A 37-year-old man suffering from failed back surgery syndrome received an ITDAS implantation, and the ITDAS was refilled with morphine every 3 months. When the patient visited the hospital 18 months after ITDAS implantation for a refill, the amount of delivered morphine sulfate was much less than expected. Movement of the pump rotor was examined with fluoroscopy; however, it was normal. CSF aspiration through the catheter access port was impossible. When the intrathecal catheter was removed, we observed that the side hole and lumen of the catheter was plugged.

Effect of Injection Speed on the Anesthetic Level and Duration of Hypobaric Spinal Anesthesia with 0.1% Tetracaine in Jack-Knife Position at 15o Head-down Tilting / 대한마취과학회지

BACKGROUND: The speed of injection of local anesthetic solutions into the subarachnoid space may influence the spread of these agents in the cerebrospinal fluid by the amount of turbulence generated, especially with large volume. To determine the proper injection speed of anesthetics in hypobaric spinal anesthesia on jack-knife position, the anesthetic level and duration were measured with the fast or slow injection speed. METHODS: Twenty patients for perianal surgery in jack-knife position under hypobaric spinal anesthesia were randomly assigned to one of two groups. Tetracaine (0.1%) in distilled water 5 ml was administered to all the patients. Group I patients received the drug with the speed of injection as 5 ml/20 sec (15 ml/min) and the others (Group II) as 5 ml/4 min (1.25 ml/min). The mean arterial pressures and heart rates at the preanesthetic period, and 5, 10, 15 and 20 min after the end of injection were measured. The anesthetic levels at 5, 10, 15 and 20 min after the injection and anesthesia duration were measured. RESULTS: There was no significant difference in mean arterial pressures, heart rates and anesthetic duration between two groups. The anesthetic level 20 min after the injection was higher in Group I than Group II, and not different at the other time sequences. CONCLUSION: At the injection speed within 1.25-15 ml/min in hypobaric spinal anesthesia on jack-knife position at 15o head-down, we acquired appropriate anesthetic level and duration for perianal surgery without any undesirable effects.