Metal Needle Research Articles

Tubular glassy carbon microneedles with fullerene-like tips for biomedical applications.

Glassy carbon, in general, is made by the pyrolysis of polymeric materials and has been the subject of research for at least fifty years. However, as understanding its microstructure is far from straightforward, it continues to be an area of active research. Glassy carbon adopts different allotropes depending on the hybridizations of the C–C bond, that is, sp, sp2, or sp3. Furthermore, a variety of short-range ordering effects can interact with each other and this, along with the effects of microporosity, grain boundaries, and defects, render this a fascinating material. Following the nanoarchitectonics concept of bottom-up creation of functional materials, we use methane rather than a polymer to form glassy carbon. Here we show that tubular glassy carbon microneedles with fullerene-like tips form when methane undergoes pyrolysis on a curved alumina surface. X-ray diffraction of these glassy carbon tubules shows long-range order with a d-spacing of 4.89 Å, which is indicative of glassy carbon. Raman spectroscopy shows the material to be graphitic in nature, and SEM shows the fullerene-like structure of the material. This work provides new insights into the structure of glassy carbons relevant to the application of glassy carbons as a biomaterial, for example, as a new form of carbon-based microneedles. Since metallic needles can introduce toxic/allergenic species into susceptible subjects, this alternative carbon-based microneedle form has great potential as a replacement biomedical material for metallic needles in the field of neural engineering and as acupuncture needles.

Management of traumatic incarceration of metal needle in the knee of children: A case series

IntroductionForeign bodies constitute a frequent and alarming problem in pediatrics emergencies. The nature, presentation and localization of the foreign bodies are variable. Their management depends on the available technical platform.Presentation of casesWe report three retrospective cases of traumatic embedded pieces of metal needles in the knee in a 6-year-old male, an 8-year-old female and a 5-year-old male. All the cases were successfully managed in our unit. The left side was involved in one case. X-ray and brilliance amplifier were used to diagnosing and removing the foreign bodies from the knee. The postoperative course was uneventful except in the case of the 8-year-old female who had osteoarthritis.DiscussionIn low-income countries, simple extraction from the soft tissue or arthrotomy could be used to removing foreign bodies in the knee as arthroscopy is often unavailable.ConclusionThe traumatic impalement of pieces of metal needle in the child’s knee is a rare event. The circumstances of these accidents are very difficult to reconstitute. The arthroscopy has an advantage in their extraction. However, the arthrotomy guided by brilliance amplifier remains the only alternative in low-income countries.

Liver tumor ablation enhancement by induction-heating system with bitter-like deep magnetic field coil.

The heated metal needle used for tumor thermotherapy is considered crucial for enhancing the practicality of cauterization using electromagnetic induction-heating techniques. In this study, a novel coil capable of producing a deep magnetic field is designed. In the proposed design, the coil structure is improved to enhance the intensity of the coil's deep magnetic field and its suitability for deep-tissue cauterization. Furthermore, a series of experiments are conducted using a single and consistent input current. The heating experiments are conducted at varying depths by placing the needle beneath the coil. The proposed coil significantly increases the induction-heating temperature and provides a solution to the long-standing problem of insufficient needle temperature. This research has also improved the usability of the induction-heating equipment in the field of deep tumor ablation.

Pentadecapeptide BPC 157 Anti‐Ulcer Effect After Stomach Perforation also Opposed the Intracranial Hypertension (Superior Sagittal Sinus), Portal and Caval Hypertension and Aortal Hypotension

We report that rat stomach perforation (surgery with 5‐mm diameter metal needle on the ventral side in the prepyloric area) induced a defect that would not heal. Also, stomach perforation rapidly induced the intracranial hypertension (superior sagittal sinus), portal and caval hypertension and aortal hypotension. Stable gastric pentadecapeptide BPC 157 largely attenuated or eliminated these pressure disturbances. Finally, BPC 157 completely healed stomach defect. Previously, BPC 157 largely attenuated or even eliminated the consequences of Budd‐Chiari syndrome in rats, in particular, portal and caval hypertension and aortal hypotension, and then, huge thrombosis in both veins and arteries, and multiple organ dysfunction syndrome, heart, lung, liver, kidney and gastrointestinal lesions. These beneficial effects may relieve a Virchow's triad situation that may be commonly presented as well as counteracted (i.e.,duodenal venous congestion lesions (World J Gastroenterol 2018), perforated cecum (World J Gastroenterol 2018), bile duct ligation induced liver cirrhosis and portal hypertension (Eur J Pharmacol 2109), Pringle maneuver, ischemia, reperfusion (World J Hepatol 2020), and suprahepatic occlusion of the inferior caval vein (Budd‐Chiari‐syndrome) (World J Gastrointest Pathophysiol 2020)). Likewise, given in reperfusion, after clamping of the common carotid arteries, BPC 157 counteracted stroke (i.e., both early and delayed neural hippocampal damage, achieving also full functional recovery) (Brain Behav 2020).MethodsTherapy (BPC 157 (10 µg or 10 ng/kg) or saline (5 ml/kg)) was given intragatrically, at 1 min after stomach perforation. At 5 min after stomach perforation, as described before (World J Hepatol 2020), recordings were made in deeply anesthetized rats. Briefly, a cannula (BD Neoflon™ Cannula) was connected to a pressure transducer (78534C MONITOR/ TERMINAL; Hewlett Packard, USA) inserted into the superior sagittal sinus, and portal vein, and inferior vena cava, and abdominal aorta at the level of the bifurcation. We used five minutes recording. For superior sagittal sinus pressure recording, we made a single burr hole in the rostral part of the sagittal suture, above the superior sagittal sinus, and cannulated superior sagittal sinus anterior part by Braun intravenous cannulas, and then, in laparatomized rats, we recorded portal vein, inferior vena cava and abdominal aorta pressure.ResultsWithout therapy, the severely increased intracranial hypertension (10±2 mmHg in superior sagittal sinus), portal (33±4 mmHg) and caval (28±3 mmHg) hypertension and aortal hypotension (59±3 mmHg) occurred rapidly. Both BPC 157 regimens markedly counteracted intracranial hypertension (‐6±2 mmHg in superior sagittal sinus), portal (6±2 mmHg) and caval (5±2 mmHg) hypertension and aortal hypotension (81±3 mmHg) (i.e., 10 ng).ConclusionBPC 157 anti‐ulcer effect also opposed the intracranial hypertension (superior sagittal sinus), portal and caval hypertension and aortal hypotension.

Differences in morphological, biochemical, and genetic characteristics of grape explants grafted using various micrografting techniques

This study aimed to improve the micrografting technique for rapid in vitro grapevine plantlet propagation using Flame Seedless scion and Freedom as rootstock. Explants obtained in vitro were cultured in MS media containing 0.4 mg L-1 BAP. For micrografting, six methods were used: sterile wire ties, sterile metal needle, wax, aluminum foil, gel, and callus. Data was collected on morphological and biochemical parameters in micrografts produced using various procedures. With various degrees of success, all in vitro micrografting procedures successfully produced grafts. The best results of morphological parameters were recorded in micrografting in wax method with the highest survival (83.88%), number of shoots/explants (1.77), shoot length (1.66 cm), leaves/shoot (4.55), rooting (58.20 %), root length (1.27 cm). In contrast, the callus method had the least value for these parameters. Wax and aluminum foil methods were found to be a promising alternative to traditional grapevine propagation methods in the study.

Using an insulating fiber as the sampling probe and ionization substrate for ambient ionization-mass spectrometric analysis of volatile, semi-volatile, and polar analytes.

A sharp metal needle used as the ionization emitter in conventional atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) is usually required for analyte ionization through corona discharge (i.e., gas discharge). Nevertheless, we herein demonstrate that an insulating fiber (tip diameter: 10-60µm; length: ~ 1cm) made of glass or bamboo can function as an APCI-like ionization emitter. Although no direct electric contact is made on the fiber, the ionization of volatiles and semi-volatiles occurs when the fiber is placed close (~ 1mm) to the inlet of the mass spectrometer. No analyte ion signals can be observed without placing the insulating fiber in front of the mass spectrometer. The generation of ion species mainly relies on the electric field provided by the mass spectrometer. Presumably, owing to the high electric field provided by the mass spectrometer, the dielectric breakdown voltages of gas molecules in the air and the fiber are overcome, leading to the ionization of analytes in gas phase. In addition, the insulating fiber can function as a holder for sample solutions. Electrospray ionization-like processes derived from polar analytes such as amino acids, peptides, and proteins can readily occur when the insulating fiber deposited with a sample droplet is placed close to the inlet of the mass spectrometer. The feasibility of using the current approach for the detection of nonpolar and polar analytes from complex fetal bovine serum samples without tedious sample pretreatment is demonstrated in this work. The main advantage of using the suggested fiber is that the fiber can be used as the sampling probe to pick up samples and placed in front of a mass spectrometer for direct MS analysis. The application of using a robust, insulating, and disposable probe to pick up samples from real samples such as onion, honey, and pork samples followed by direct MS analysis is also demonstrated.

Improving needle visibility in LED-based photoacoustic imaging using deep learning with semi-synthetic datasets

Photoacoustic imaging has shown great potential for guiding minimally invasive procedures by accurate identification of critical tissue targets and invasive medical devices (such as metallic needles). The use of light emitting diodes (LEDs) as the excitation light sources accelerates its clinical translation owing to its high affordability and portability. However, needle visibility in LED-based photoacoustic imaging is compromised primarily due to its low optical fluence. In this work, we propose a deep learning framework based on U-Net to improve the visibility of clinical metallic needles with a LED-based photoacoustic and ultrasound imaging system. To address the complexity of capturing ground truth for real data and the poor realism of purely simulated data, this framework included the generation of semi-synthetic training datasets combining both simulated data to represent features from the needles and in vivo measurements for tissue background. Evaluation of the trained neural network was performed with needle insertions into blood-vessel-mimicking phantoms, pork joint tissue ex vivo and measurements on human volunteers. This deep learning-based framework substantially improved the needle visibility in photoacoustic imaging in vivo compared to conventional reconstruction by suppressing background noise and image artefacts, achieving 5.8 and 4.5 times improvements in terms of signal-to-noise ratio and the modified Hausdorff distance, respectively. Thus, the proposed framework could be helpful for reducing complications during percutaneous needle insertions by accurate identification of clinical needles in photoacoustic imaging.

Force and Velocity Based Puncture Detection in Robot Assisted Retinal Vein Cannulation: In-Vivo Study.

Retinal vein cannulation is a technically demanding surgical procedure and its feasibility may rely on using advanced surgical robots equipped with force-sensing microneedles. Reliable detection of the moment of venous puncture is important, to either alert or prevent the clinician from double puncturing the vessel and damaging the retinal surface beneath. This paper reports the first in-vivo retinal vein cannulation trial on rabbit eyes, using sensorized metal needles, and investigates puncture detection. We utilized total of four indices including two previously demonstrated ones and two new indices, based on the velocity and force of the needle tip and the correlation between the needle-tissue and tool-sclera interaction forces. We also studied the effect of detection timespan on the performance of detecting actual punctures. The new indices, when used in conjunction with the previous algorithm, improved the detection rate form 75% to 92%, but slightly increased the number of false detections from 37 to 43. Increasing the detection window improved the detection performance, at the cost of adding to the delay. The current algorithm can supplement the surgeons' visual feedback and surgical judgment. To achieve automatic puncture detection, more measurements and further analysis are required. Subsequent in-vivo studies in other animals, such as pigs with their more human like eye anatomy, are required, before clinical trials. The study provides promising results and the criteria developed may serve as guidelines for further investigation into puncture detection in in-vivo retinal vein cannulation.

Accelerating Cell Migration along Radially Aligned Nanofibers through the Addition of Electrosprayed Nanoparticles in a Radial Density Gradient.

Scaffolds capable of promoting cell migration from the periphery towards the center along the radial direction hold promises for tissue regeneration. Here we report a simple and general method based on masked electrospray for the fabrication of such scaffolds by depositing collagen nanoparticles on radially-aligned nanofibers in a radial density gradient. Placed between the metallic needle and the collector, an aperture with tunable opening sizes serves as the mask. By increasing the size of the opening at a fixed speed, the electrosprayed particles take a radial density gradient that decreases from the center to the periphery. When deposited on a glass slide, the radial density gradient of collagen nanoparticles promotes the migration of fibroblasts from the periphery towards the center. By replacing the glass slide with a scaffold comprised of radially-aligned nanofibers, a synergetic effect arises to further accelerate cell migration along the radial direction. The synergistic effect can be attributed to a unique combination of the topographic cue arising from the aligned nanofibers and the haptotactic cue enabled by the graded nanoparticles. This work demonstrates a method to maximize cell migration from the periphery towards the center through a combination of topographic and haptotactic cues.

CT-Guided Femoral Approach for Psoas Muscle Abscess Drainage.

To evaluate the feasibility and safety of the computed tomography (CT)-guided femoral approach for draining a psoas muscle abscess (PMA). Between January 2014 and November 2018, the CT-guided femoral approach was employed for 9 abscesses in 8 patients who could not tolerate the prone position because of advanced age or other underlying conditions. A 17-gauge blunt metal needle was used to puncture the iliacus muscle below the groin under CT fluoroscopic guidance. A drainage catheter was then placed within the abscess cavity in the psoas major muscle. Technical success, clinical success, complications, the drainage therapy duration, susceptibility to antibiotics, survival, and recurrence were evaluated. The technical success rate was 100% among all nine lesions. The clinical success rate was 89% among all eight patients. One patient died of concomitant meningitis 15days after the procedure. No patients developed therapy-related complications. The median duration of the drainage therapy was 15days (range 6-71days). Appropriate antibiotics based on the culture susceptibility were achieved in all patients. Four patients survived, and the remaining four died at 15 to 758days (median, 36days) after the procedure; no therapy-related deaths occurred. No recurrence was seen. The CT-guided femoral approach seems feasible, effective, and safe for draining psoas muscle abscesses in ill patients who cannot tolerate the prone position.

Results of sole postoperative interstitial, high-dose-rate brachytherapy of T1–2 tongue tumours

PurposeTo describe the results of treating tongue cancer patients with single postoperative interstitial, high-dose-rate (HDR) brachytherapy (BT) after resection.MethodsBetween January 1998 and April 2019, 45 patients with squamous cell histology, stage T1–2N0–1M0 tongue tumours were treated by surgery followed by a single HDR BT in case of negative prognostic factors (close or positive surgical margin, lymphovascular and/or perineural invasion). The average dose was 29 Gy (range: 10–45 Gy) and rigid metal needles were used in 11 (24%) and flexible plastic catheters in 34 cases (76%). Survival parameters, toxicities and the prognostic factors influencing survival were analysed.ResultsDuring a mean follow-up of 103 months (range: 16–260 months) for surviving patients, the 10-year local and regional control (LC, RC), overall survival (OS), and disease-specific survival (DSS) probabilities were 85, 73, 34 and 63%, respectively. The incidence of local grade 1, 2 and 3 mucositis was 23, 73 and 4%, respectively. As a serious (grade 4), late side effect, soft tissue necrosis developed in 3 cases (7%). In a univariate analysis, there was a significant correlation between lymphovascular invasion and RC (p = 0.0118) as well as cervical recurrence and DSS (p < 0.0001).ConclusionSole postoperative HDR brachytherapy can be an effective method in case of negative prognostic factors in the treatment of early, resectable tongue tumours. Comparing the results of patients treated with postoperative BT to those who were managed with surgery or BT alone known from the literature, a slightly more favourable LC can be achieved with the combination therapy, demonstrating the potential compensating effect of BT on adverse prognostic factors, while the developing severe, grade 4 toxicity rate remains low.

Plastic cannulae versus metal needle cannulation in haemodialysis: Results of an international survey from the nurse perspective.

In haemodialysis is key to successfully obtaining cannulation of the arteriovenous fistula (AVF). The literature agrees that cannulation, failing in the initial maturation period, can lead to delayed dialysis, haematoma, scarring, needle phobia and loss of confidence in the cannulator. The introduction of plastic cannulae for haemodialysis has changed cannulation practice positively, preventing frequent complications such as infiltration or trauma. Despite that, most countries have continued to use metal cannulation, in particular in Europe. This study investigates the common use of plastic cannulae versus metal needles for cannulation in dialysis units and explores the implications of focusing on the side effects of cannulation. The study is a cross-sectional survey. A questionnaire was created by a team of experts from the European Dialysis Transplant Nurse Association/European Renal Care Association (EDTNA/ERCA) to address the study's aims and sent online to nurse members. Data collected suggested a strong resistance towards using plastic cannulae, with few respondents claiming to use these cannulas. Most of the respondents were female (74%), Europeans, working in nephrology for more than 10 years and most worked in the public sector. There was a strong correlation between the use of plastic cannulae and fewer adverse events in elbow located AVF and newly created or fragile AVF. The results are in line with the current literature. Possible resistance to the use of the plastic device includes the difference in cost between the two devices in favour of metal needles. However, it should be considered that the lower number of adverse events, in particular infiltration and haematoma caused by the metal needle, involves a considerable saving both in money and in terms of time and distress for the patient.

Duodenal dislodgement of an ingested sharp foreign body by mucosal unfolding "Gilan maneuver"; A novel surgical approach.

Introduction and importanceForeign body (FB) ingestion is a common challenge for pediatric health care providers globally. Although endoscopic approach for FB extraction is recommended, surgery remains life giving specifically in developing countries. We presented a novel surgical approach called ‘Gilan maneuver’ for removal of FB which lodged in duodenal loop.Case presentationAn eighteen months old male infant referred to emergency department while he lied on his mother's arm. Parents stated their son has ingested a sharp metallic pointy thick needle which applies for cattle injection. On examination mid epigastric tenderness was remarkable. Laboratory finding was normal. Plain thoracoabdominal radiologic study confirmed the diagnosis. Patient underwent explorative laparotomy and the needle was removed through ‘Gilan maneuver’ in which mucosal unfolding of duodenal loop facilitated dislodgement of the FB and it was extracted on the jujenal side.Clinical discussionDuodenal lodge of sharp FB is rare and could be masked by gastric deposition diagnosis. Mucosal folding, narrow luminal diameter, retroperitoneal adherence, and hard surgical anatomy of the duodenal loop make both sharp and large FBs spontaneous dislodgement and favorable surgical outcome relatively unanticipated.ConclusionDespite rarity of duodenal deposition of FB it is possible and could be harmful due to adjacent unforgiving organs. Although endoscopic extraction of FB is generally recommended in guidelines, surgical approach is safe and could be considered.

Deformation modes of an oil-water interface under a local electric field: From Taylor cones to surface dimples

Fluidic interfaces disintegrate under sufficiently strong electric fields, leading to electrohydrodynamic (EHD) tip streaming. Taylor cones, which emit charged droplets from the tip of a conical cusp, are among the most prominent and well-studied examples of EHD instabilities. In liquid-liquid systems, more complex interface deformation modes than simple Taylor cones can be observed, with the interface being pushed away from the electrode, and additional cone structures emerging from the rim of the dimple. In this article, we investigate the mechanisms behind these deformation modes experimentally and numerically, and demonstrate that the presence of droplets triggers the dimple at the interface. In order to characterize the underlying processes, we replace the pin electrode by a hollow metallic needle with a prescribed electrolyte volume flow. The submerged electrospray introduces droplets of an aqueous KCl solution with varying ion concentrations into silicone oils with varying viscosities. By measuring the corresponding electric current and by optical investigation of the interface deformation, we study the system response to variations of the ionic concentration, viscosity, applied voltage as well as flow rate. In addition to the experiments, we use a finite element solver and compute the charge transport due to the droplets in the oil phase. Further, we compute the electric potential distribution, flow field and interface deformation. After calibration of our model with particle tracking velocimetry data of the flow inside the oil phase, we reproduce the experimentally observed dimple at the liquid-liquid interface. In summary, this work highlights the importance of charged droplets for the complex dynamic modes observed when a liquid-liquid interface is exposed to a local electric field.

Characteristics Analysis of Water Needle Induced Electrical Trees in XLPE

In this paper, electrical trees initiated from water and metal needle are investigated, and the inception and morphological characteristics of water needle electrical trees are analyzed. The existing literature shows that electrical trees can be initiated from the metal needle or transformed from the water trees. But in this study, it is found that the electrical tree can be directly induced by water needle in addition to the above cases. Moreover, the comparative results also indicate that the electrical trees initiated from water needle and metal needle have different inception features and morphological characteristics. To obtain the water needle electrical trees initiation and development mechanism, the water needle tips are observed before and after the sample degas process. Besides, the electric field distribution of the metal needle tip, the water needle tip before and after pretreatment, and of tree branch tip during the electrical tree development are calculated. The observations and calculations results show that before the degas pretreatment, a micro-gas cavity is formed at the water needle tip due to the tension of the water surface. The cavity at the needle tip may cause and support partial discharge (PD), causing accumulative damage and material defects. Then the density of defects becomes sufficiently large, and a tree branch can be formed. After the branch formation, the water flows into the tree branch, and the micro-gas remains at the branch tip, which may facilitate the PD, and trees propagation, resulting in the diversified morphological characteristics of the water needle electrical trees.

Investigating the mechanisms of brain innate immune activation following bacterial infection in Drosophila

AbstractBackgroundCentral Nervous System (CNS) infections caused by bacteria and resulting immune responses could underlie neurodegenerative diseases such as Alzheimer’s disease (AD). Neuroinflammation is a well‐known component of AD furthering disease pathology and progression. However, the mechanisms by which infectious agents contribute to neuroinflammatory reactions and neurodegeneration are not fully understood. The model organism Drosophila melanogaster shares conserved mechanisms of innate immune activation and neural development with mammals, and thus represents an excellent system for the investigation of pathogen‐associated neurodegeneration. Previous work in flies has shown that bacterial brain injection results in age‐dependent neurodegeneration and impaired locomotor activity. Furthermore, these phenotypes depend on NF‐κB in both glia and neurons, suggesting that long‐term inflammatory processes take place in both cell types. However, a detailed picture of innate immune pathway activation in the Drosophila brain following bacterial infection is lacking. Here, we investigate the activation in the brain of the two Drosophila NF‐ κB pathways, Toll and Immune deficiency (IMD), in response to infection with Gram‐positive and Gram‐negative bacteria, respectively.MethodFly brains are infected by pricking heads with a thin, metal needle, dipped into concentrated pellets of overnight cultured bacterial solutions. Activation of NF‐κB pathways in brain cell types is assayed using immunohistochemistry and confocal microscopy of flies carrying fluorescent NF‐κB reporters. The dependence of canonical NF‐κB pathway components is assayed using quantitative reverse‐transcription PCR (RT‐qPCR) using RNA isolated from dissected brains of control‐injected or bacterially injected flies.ResultOur preliminary results show that brain bacterial injection leads to the activation of GFP reporters for both Toll and IMD pathways in multiple glial subtypes in the fly brain 24h following infection. We have optimized a protocol for brain‐specific gene expression of NF‐κB targets and are currently examining the response to bacterial challenge of multiple mutants for components of the Toll and IMD pathways.ConclusionWe have established a Drosophila model of bacterial brain infection that allows studying the long‐term consequences of pathogen‐mediated neuroinflammatory reactions associated with neurodegeneration. Our system could be used to identify the processes of immediate protection as well as the long‐term effects of brain infection.

Factors which influence the complications of external ventricular cerebrospinal fluid drainage.

External ventricular drainage (EVD) is one of the most common neurosurgical procedures in emergencies. This study aims to find out which factors influence the occurrence of EVD-related complications in a comparative investigation of metal needles and polyurethane catheters. This is the first clinical study comparing these two systems. Adult patients undergoing pre-coronal EVD placement via freehand burr hole trepanation were included in this prospective study. The exclusion criteria were the open EVD insertion and/or a pre-existing infectious disease of the central nervous system. Two hundred consecutive patients were enrolled. Of these, 100 patients were treated by using metal EVD (group 1) and 100 patients with polyurethane catheters (group 2). The overall complication rate was 26% (misplacement 13.5%, hemorrhage 12.5%, infection 2.5%, and dislocation 1%) without statistically significant differences between both groups. Generalized brain edema and midline shift had a significant influence on misplacements (generalized brain edema: p = 0.0002, Cramer-V: 0.307, OR = 7.364, 95% CI: 2.691-20.148; all patients: p = 0.001, Cramer-V: 0.48, OR = 43.5, 95% CI: 4.327-437.295; group 1: p = 0.047, Cramer-V: 0.216, OR = 3.75, 95% CI: 1.064-13.221; group 2: midline shift: p = 0.038, Cramer-V: 0.195, OR = 3.626, 95% CI: 1.389-9.464) all patients: p = 0.053, Cramer-V: 0.231, OR = 5.533, 95% CI 1.131-27.081; group 1: p = 0.138, Cramer-V: 0.168, OR = 2.769, 95% CI: 0.813-9.429 group 2. Hemorrhages were associated with the use of oral anticoagulants or antiplatelet therapy (p = 0.002; Cramer-V: 0.220, OR = 3.798, 95% CI: 1.572-9.175) with a statistically similar influence in both groups. Generalized brain edema has a significant influence on misplacements in both groups. Midline shift lost its significance when considering only the patients in group 2. Patients under oral anticoagulation and antiplatelet therapy have increased odds of EVD-associated hemorrhage. Metal needles and polyurethane catheters are equivalent in terms of patient safety when there are no midline shift and generalized brain edema.

Efficacy and Safety of Plastic Cannulae Compared with Metal Needles in the Initial Use of an Arteriovenous Fistulae in Incident Hemodialysis Patients: A Randomized Controlled Study

Efficacy and Safety of Plastic Cannulae Compared with Metal Needles in the Initial Use of an Arteriovenous Fistulae in Incident Hemodialysis Patients: A Randomized Controlled Study

Minimal artifact actively shimmed metallic needles in MRI.

Signal voids caused by metallic needles pose visualization and monitoring challenges in many MRI applications. In this work, we explore a solution to this problem in the form of an active shim insert that fits inside a needle and corrects the field disturbance (ΔB0 ) caused by the needle outside of it. The ΔB0 induced by a 4 mm outside-diameter titanium needle at 3T is modeled and a two-coil orthogonal shim set is designed and fabricated to shim the ΔB0 . Signal recovery around the needle is assessed in multiple orientations in a water phantom with four different pulse sequences. Phase stability around the needle is assessed in an ex-vivo porcine tissue dynamic gradient echo experiment with and without shimming. Additionally, heating of the shim insert is assessed under 8 min of continuous operation with 1A current and concurrent imaging. An average recovery of ~63% of lost signal around the needle across orientations is shown with active shimming with a maximum current of 1.172 A. Signal recovery and correction of the underlying ΔB0 is shown to be independent of imaging sequence. Needle-induced phase gradients outside the perceptible signal void are also minimized with active shimming. Temperature rise of up to 0.9° Celsius is noted over 8 min of continuous 1A active shimming operation. A sequence independent method for minimization of metallic needle induced signal loss using an active shim insert is presented. The method has potential benefits in a range of qualitative and quantitative interventional MRI applications.

The effect of skin tension, needle diameter and insertion velocity on the fracture properties of porcine tissue

Using metal needles to penetrate skin tissue is common in medical treatments for the delivery of medication or minimally invasive surgery. In most applications the fracture properties of skin tissue is not important as the human surgeon has full control over the needle. Given that robotically controlled surgeries and self applied medical devices have become increasingly popular, a better understanding of the fracture properties and how to mathematically model the fracture process is needed. Experiments measuring the force required to fracture porcine skin tissue were done while varying the applied skin tension, needle insertion speed and needle diameter. The applied skin tension was found to have the greatest influence on the fracture properties, while the insertion speed was found to have a negligible impact. The variance in experimental results was not well explained by the three independent variables alone, suggesting that additional parameters influence the fracture process.