Is lumbar erector spinae plane block (L-ESPB) a lumbar plexus block?: a case report of three cases

Background Lumbar erector spinae plane block (L-ESPB) is being used in fractured hip patients for the postoperative pain relief and as a sole anesthetic technique. Various clinical and cadaveric studies have differences of opinion about its mechanism of action and pathways of local anesthetic spread; however, the role of lumbar plexus (LP) in the mechanism of action is still not considered. In our clinical experience, we observed that the action on LP could be a pathway for the analgesic action of local anesthetic along with paravertebral spread. Case presentation We report here three cases of the fractured hip who were given L-ESPB for postoperative pain management. The radiological examination was done after injection of non-ionic contrast to know the spread of local anesthetic. In two cases, the contrast spread was seen towards LP and in one case spread of contrast was observed towards the paravertebral area. Conclusions Effect of local anesthetic on the lumbar plexus is one of the plausible pathways in L-ESPB for its analgesic mechanism of action.

Abstract 1122‐000236: Intravascular Delivery and Crosslinking of Photosensitive Hydrogels for Embolizing Animal Models of AVMs and Tumors

Introduction : Embolization represents a minimally invasive treatment modality for arteriovenous malformations (AVMs), tumors, and other indications, but can be limited by currently available embolic agents, in terms of safety and efficacy. Discovery of new and improved agents could lead to better treatment outcomes. The goal of this project was to test a novel embolization methodology for the treatment of AVMs and tumors. Methods : We formulated low‐viscosity, shear‐thinning hydrogel formulations which were mixed with a photo‐initator agent and non‐ionic contrast medium. We then developed a method of intravascular hydrogel delivery with photo crosslinking at the tip of the catheter, using an integrated optical fibre. This allowed for rapid transition from a low viscosity liquid to a crosslinked solid‐state hydrogel to block blood flow to the vascular target. In addition, the UV intensity can be dynamically modulated, in real‐time, to modify the degree of crosslinking and thus the viscosity of the embolic agent. We utilized the swine rete mirabile as an animal model for AVMs, and the swine renal arterial tree (inferior segmental artery) as a model for hypervascular tumors. 5 animals were utilized without prior preparation. Embolization was graded based on degree of complete obliteration of the rete nidus or the renal arterial tree. Any non‐target embolization or other complications were recorded. Follow‐up angiography was performed at the 4‐week interval. Results : With a combination of shear‐thinning properties and dynamic modulation of photo crosslinking, we show that we are able to deliver an embolic agent with a viscosity range of up to 10^4 Pa*s through a single low viscosity precursor that is injectable through microcatheters (Figure 1). Using this methodology, hydrogel embolization was technically successful in all animals. Following embolization, 4/5 rete mirabile and 5/5 inferior renal arterial trees were completely obliterated. Representative angiographic images are shown in Figures 2 and 3. There were no instances of clinical or angiographic complications. Conclusions : We demonstrated a novel method of intravascular delivery of low viscosity photosensitive hydrogels, with photo crosslinking at the tip of the catheter, to successfully embolize animal models for AVMs and tumors. This promising technology will be investigated further with longer‐term comparative animal trials.

Comparison of Renal Parenchymal Enhancement Using Different Concentration of Iodinated Contrast Media in MDCT

Many investigators have described comparisons of contrast media with different iodine concentrations in the enhancement of multiple organs and vessels on CT scans. Contrary to other solid organs, the kidney excretes waste products, including contrast media, via the cortex, medulla, and pelvicalyceal system. For the kidney, there are characteristic enhancing techniques such as the use of the arterial phase for cortex and venous phase for medullary during contrast CT imaging. In our study, we compared the degree of renal parenchymal enhancement in the Hounsfield Unit (HU) by the use of 350 and 370 mg I/ml in contrast enhanced computed tomography (CECT) abdomen at the origin of renal artery of right and left Kidney in the arterial phase for both groups. The comparison of renal parenchymal enhancement between the A group and B group showed that the renal parenchymal enhancement is higher in B group. This was a prospective randomized study in which 116 participants were allocated in two groups using the random convenience sampling method. The subjects were divided into two groups; Group A (350 mgI/ml and Group B (370 mgI/ml). All data were analyzed by an independent t-test to obtain the mean difference between all the variables using 350 mgI/ml and 370mgI/ml. Quantitative data like age, height, weight, Body Mass Index(BMI), pulse rate, creatinine, flow rate, contrast volume, and ejection fraction were presented as mean and standard deviation using an independent t-test. Qualitative data like gender was presented as a percentage. P-value was calculated using an independent t-test. P-value <0.05 was considered to be statistically significant. Data were analyzed by statistical Package for Social Science version 20.0 (IBM corporation, New York, 2014). Analyzing the data using the independent-test revealed that differences between the two groups were found to be statistically significant (P=0.029). The comparison of renal parenchymal enhancement between the A group and B group showed that the renal parenchymal enhancement is higher in the B group with a t = -2.213 and is statistically significant (P = 0.029). Non-ionic contrast medium of concentration 370 mg I/ml showed higher mean renal parenchyma peak enhancement as compared to 350 mg I/ml. Further, our study showed that the renal parenchymal enhancement pattern between A group and B group was affected by weight, BMI, and pulse rate and contrast volume.

Ionic contrast across a lipid membrane for Debye length extension: towards an ultimate bioelectronic transducer

Despite technological advances in biomolecule detections, evaluation of molecular interactions via potentiometric devices under ion-enriched solutions has remained a long-standing problem. To avoid severe performance degradation of bioelectronics by ionic screening effects, we cover probe surfaces of field effect transistors with a single film of the supported lipid bilayer, and realize respectable potentiometric signals from receptor–ligand bindings irrespective of ionic strength of bulky solutions by placing an ion-free water layer underneath the supported lipid bilayer. High-energy X-ray reflectometry together with the circuit analysis and molecular dynamics simulation discovered biochemical findings that effective electrical signals dominantly originated from the sub-nanoscale conformational change of lipids in the course of receptor–ligand bindings. Beyond thorough analysis on the underlying mechanism at the molecular level, the proposed supported lipid bilayer-field effect transistor platform ensures the world-record level of sensitivity in molecular detection with excellent reproducibility regardless of molecular charges and environmental ionic conditions.

Ionic and non-ionic intravenous X-ray contrast media: antibacterial agents?

X-ray contrast media have been reported to have inhibitory effects on bacterial growth. Despite its potentially beneficial effect on patients, these features of contrast media have received relatively little attention in the medical literature in the past decades. The aim of this review is to evaluate the literature concerning the bactericidal and bacteriostatic effects of X-ray contrast media, specifically if there is a known difference concerning these effects between ionic and non-ionic contrast media. Systematic literature review was performed for the years of publication between 1911 and 2019. Since the publication of Grossich in 1911, the effect of iodine on the treatment of superficial infections in surgical procedures has been established clinical knowledge. Bacteriostatic and bactericidal effects of ionic X-ray contrast media are well established. However, non-ionic contrast agents have been the subject of little research in this respect. In past decades, the hypothesis emerged in the literature that mainly the concentration of free iodine might be responsible for any bacteriostatic or bactericidal effect of ionic X-ray contrast media. Nowadays, however, only non-ionic contrast media are used. The question regarding the mechanism and magnitude of bacteriostatic or bactericidal effects of these, non-ionic contrast media, could not be answered conclusively from this review. Non-ionic contrast media could be used intentionally when a local antibacterial effect is intended (e.g. in percutaneous abscess drainage), as well as to reduce the overall dose of antibiotics administered to a patient. Thus, this question remains relevant and might constitute the area of future research.

Right Sided Aortic Arch with Aberrant Left Subclavian Artery from Kommerell’s Diverticulum, a Cause of Persistent Dysphagia in an Adult: A Case Report

Congenital variations and anomalies of the aortic arch are important entity in vascular imaging. Most of them are asymptomatic. About 30-40% presents with tracheo-oesophageal symptoms like dyspnea and dysphagia. A 27 year-old female presented with persistent dysphagia for 6 months duration and cause of persistent dysphagia was the right sided aortic arch with aberrant left subcalvian artery from Kommerell’s diverticulum. The diagnosis was made through combination of chest X-Ray, echocardiography, non-ionic contrast swallow and Computed Tomography angiography. Non-invasive modalities (CT and MR Angiography) play an important role in diagnosis and pre-operative surgical planning providing relationship with the surrounding structures especially trachea and esophagus.

Experimental Analysis of the Utility of Liquid Metal Gallium as a Contrast Agent for CT Hepatic Artery Angiography in Living Rabbits

CT angiography (CTA) technology, as a non-invasive or minimally invasive examination method, is commonly used in the clinic to obtain vascular network images, and iodinated contrast agents play a vital role in it. At present, the second-generation non-ionic contrast agent ioversol are most commonly used in CTA, but its preparation process is complicated, the manufacture technology of it is high, and it is associated with some adverse drug reactions (ADRs), such as allergies and drug toxicity. In this work, based on the low melting point (29.78℃) and low viscosity of liquid metal gallium, it was used for the first time as an angiographic contrast agent for in vivo hepatic artery angiography. According to the statistical analysis of the smallest visible diameter of the hepatic artery and the contrast effect between the blood vessels and their surrounding tissues in CT images, we confirmed that compared with CT imaging using ioversol for hepatic artery angiography, that using liquid metal gallium produced more intuitive and excellent vascular imaging effects.In other words, the use of liquid metal gallium as an angiographic contrast agent has a certain value in living organ angiography. However, the lower overall image quality and higher side-effects of liquid metal gallium in CTA indicate that the use of liquid metal gallium as a contrast agent for living organs still needs to overcome some problems, such as the metallic artefacts and its hypertonicity. Only in this way can liquid metal gallium become a potential contrast agent candidate for angiography in animal experiments and possibly even in the clinical.

Intrathecal iodinated contrast-induced transient spinal shock

Transient spinal shock is a previously unreported complication of intrathecal contrast. A 63-year-old man presented with the chief complaint of worsening back pain. Computed topography of lumbar spine without contrast showed a lytic lesion. After international normalized ratio (INR) correction, patient was sent for CT myelogram. After intrathecal contrast injection, the patient dropped his blood pressure profoundly and developed clinical manifestations of spinal shock. Emergent intravenous bolus fluids were initiated resulting in improvement in blood pressure. Patient’s spinal shock resolved within hours. CT myelogram was normal except previously known lytic lesion. It was concluded that the transient shock was most likely due to contrast injection. We believe that this is the first reported case of transient spinal shock following CT myelogram using water-soluble iodinated non-ionic contrast agent administered intrathecally.