Sistema de barras magnéticas. Resultados y complicaciones / Magnetically-controlled growing rods. Outcomes and complications

Introducción: El uso del sistema de barras magnéticas para el tratamiento de la escoliosis de comienzo temprano es un método utilizado en los últimos 10 años; su eficacia está respaldada por la bibliografía, pero no está exento de complicaciones. Objetivo: Analizar retrospectivamente una serie de 37 pacientes tratados con barras magnéticas en escoliosis de comienzo temprano. Materiales y Métodos: Se realizó un estudio retrospectivo entre 2014 y 2019. Se dividió a los pacientes en: grupo 1 (procedimientos primarios con barras magnéticas) y grupo 2 (conversiones de sistema tradicional a barras magnéticas). Resultados: Se incluyó a 19 niñas y 18 niños (edad promedio 8 años al operarse), las etiologías fueron variadas. Entre el grupo 1 (n = 28) y el grupo 2 (n = 9), el seguimiento promedio posoperatorio fue de 3.6 años. El valor angular promedio preoperatorio de escoliosis era de 64° (rango 39°-101°) y el de cifosis, de 51° (rango 7°-81°). El valor angular promedio de escoliosis en el posoperatorio inmediato fue de 41° (rango 17°-80°) y el de cifosis, de 34° (rango 7°-82°). Se produjeron 2 roturas de barra y una cifosis de unión proximal, 2 aflojamientos de tornillos proximales, una falla del sistema de distracción de barras magnéticas y una infección del sitio quirúrgico. Conclusiones: Nuestros resultados preliminares, aunque son a corto plazo, sugieren que la barra magnética podría ser un método eficaz en este tipo de enfermedad. Nivel de Evidencia: IV

Introduction: Magnetic Expansion Control (MAGEC) Spinal Growing Rods are a novel treatment for early-onset scoliosis (EOS). Although its efficacy is supported by the literature, it is not without complications. Materials and Methods: The aim of this study was to retrospectively analyze a series of 37 cases treated with MAGEC between 2014 to 2019. We performed a retrospective study and divided the population into two groups: GI (primary procedures with MAGEC) and GII (conversions from traditional system to MAGEC). Results: The study included 19 girls and 18 boys with a mean age of 8 years and a variety of etiologies. The average postoperative follow-up time for Group I (n=28) and Group II (n=9) was 3.6 years. The average preoperative angular value (AV) of scoliosis was 64° (39°-101°) and kyphosis 51° (7°-81°). The postoperative scoliosis AV was 41° (17°-80°) and kyphosis 34° (7°-82°). We found 2 rod ruptures and one proximal union kyphosis, two proximal screw loosenings, one MAGEC distraction system failure, and one surgical site infection. Conclusions: Although our preliminary results are short term, they suggest that MAGEC could be an effective method. Level of Evidence: IV

Research on a portable shielding-free ultra-low field magnetic resonance imaging system / 生物医学工程学杂志

The portable light-weight magnetic resonance imaging system can be deployed in special occasions such as Intensive Care Unit (ICU) and ambulances, making it possible to implement bedside monitoring imaging systems, mobile stroke units and magnetic resonance platforms in remote areas. Compared with medium and high field imaging systems, ultra-low-field magnetic resonance imaging equipment utilizes light-weight permanent magnets, which are compact and easy to move. However, the image quality is highly susceptible to external electromagnetic interference without a shielded room and there are still many key technical problems in hardware design to be solved. In this paper, the system hardware design and environmental electromagnetic interference elimination algorithm were studied. Consequently, some research results were obtained and a prototype of portable shielding-free 50 mT magnetic resonance imaging system was built. The light-weight magnet and its uniformity, coil system and noise elimination algorithm and human brain imaging were verified. Finally, high-quality images of the healthy human brain were obtained. The results of this study would provide reference for the development and application of ultra-low-field magnetic resonance imaging technology.

LXYL-P1-2 immobilized on magnetic nanoparticles and its potential application in paclitaxel production

BACKGROUND: LXYL-P1-2 is the first reported glycoside hydrolase that can catalyze the transformation of 7-b-xylosyl-10-deacetyltaxol (XDT) to 10-deacetyltaxol (DT) by removing the D-xylosyl group at the C7 position. Successful synthesis of paclitaxel by one-pot method combining the LXYL-P1-2 and 10- deacetylbaccatin III-10-b-O-acetyltransferase (DBAT) using XDT as a precursor, making LXYL-P1-2 a highly promising enzyme for the industrial production of paclitaxel. The aim of this study was to investigate the catalytic potential of LXYL-P1-2 stabilized on magnetic nanoparticles, the surface of which was modified by Ni2+-immobilized cross-linked Fe3O4@Histidine. RESULTS: The diameter of matrix was 20­40 nm. The Km value of the immobilized LXYL-P1-2 catalyzing XDT (0.145 mM) was lower than that of the free enzyme (0.452 mM), and the kcat/Km value of immobilized enzyme (12.952 mM s 1 ) was higher than the free form (8.622 mM s 1 ). The immobilized form maintained 50% of its original activity after 15 cycles of reuse. In addition, the stability of immobilized LXYL-P1-2, maintained 84.67% of its initial activity, improved in comparison with free form after 30 d storage at 4 C. CONCLUSIONS: This investigation not only provides an effective procedure for biocatalytic production of DT, but also gives an insight into the application of magnetic material immobilization technology.

Development of Magnetic Anchoring Lung Nodule Positioning Device / 中国医疗器械杂志

The magnetic anchoring lung nodule positioning device is composed of a target magnet, an anchor magnet, a coaxial puncture needle and a puncture navigation template, through these, a new type of accurate positioning technology for small pulmonary nodules is derived. The device inserts the target magnet into the both sides nearby the lung nodule under the guidance of CT. Helped by the mutual attraction of the two target magnets, they can be fixed in the lung tissue, avoiding the movement in the lung, and accurately positioning the target lung nodule before surgery. In thoracoscopic surgery, the anchor magnet and the target magnet attract each other to achieve the purpose of positioning the target nodule. The device uses the characteristics of non-contact suction of magnetic materials biomedical engineering technology, eliminating the previous procedure of direct interaction with the positioning marks, finally achieves the target of precise positioning of lung nodules and rapid surgical removal.

Magnet Quench Factors in Ramping-up Procedure / 中国医疗器械杂志

Ramping-up is the magnet current injection procedure which is under the control of resistance, voltage, current lead temperature, magnet pressure, temperature and so on. In this procedure, the factors related to the stability of the magnet such as, magnet temperature, pressure and currents are constantly changing. This procedure is the main step which the magnet-quench occurs in. This study uses the data collected during 7 years and SIMENS MRI ramping-up theory, in order to help engineers understand the key factors to reduce the magnet quench during the ramping up procedure.

Design of Magnamosis System for Endoscopic Tissue Clamping / 中国医疗器械杂志

Based on the principle of magnetic anastomosis technique, the design of magnetic anastomosis system for endoscopic tissue clamping is proposed. The system includes a semi-ring magnet, a special structure transparent cap and a detachable push rod. With the help of the existing digestive endoscopy and endoscopic tissue gripper, the endoscopic close clamping and anastomosis of the bleeding or perforated tissue can be completed. After the anastomosis, the magnet falls off and is discharged through the digestive tract. Animal experiments showed that the system was easy to use, the fistula was clamped firmly, the magnet was discharged for 7~21 days, and there was no magnet retention and digestive tract obstruction. Further safety verification, optimization of endoscopic operation, the system can be used in clinical trial.

1.5 T Nuclear Magnetic Resonance Imaging System Failure Treatment and Rectification Summary / 中国医疗器械杂志

Quench of magnetic resonance imaging system refers to the process that the superconducting condition inside the magnet is destroyed due to some reason. The large current stored in the coil is quickly converted into heat at the place where the resistance is formed, and a large amount of liquid helium in the magnet is evaporated. If it happens, it will cause huge loss to the user. We introduce the real cases of 1.5 T magnetic resonance imaging system's quench fault, maintenance treatment and management improvement, which can be used for reference by various medical institutions, so as to better strengthen the operation and maintenance management of magnetic resonance imaging system, so as to avoid the occurrence of out of tolerance fault, and do a good job in the guarantee work after the out of tolerance fault.

Ingesta de cuerpos extraños magnéticos en la edad pediátrica. Caso clínico de localización y extracción endoscópica con ayuda de un imán / Ingestion of magnetic foreign bodies during the paediatric age. Case report, location and endoscopic extraction aided by a magnet

La ingesta accidental de más de un imán puede producir complicaciones graves. Los protocolos actuales recomiendan la extracción endoscópica de ser posible. El objetivo de este trabajo es presentar un caso clínico de una ingesta de dos imanes y la técnica endoscópica de extracción. Niño de 11 años que acudió a Urgencias tras la ingesta de dos imanes, asintomático. En la radiografía de abdomen, se identificaron dos cuerpos extraños radiopacos, aparentemente unidos, en la cámara gástrica. Se realizó una endoscopía bajo anestesia general en quirófano. Para facilitar la extracción, se colocó, encima de la pared abdominal, a nivel gástrico, un imán de neodimio. En la endoscopía, se observaron dos pequeños imanes localizados y fijados en la cara anterior del estómago. Una vez localizados, se retiró el imán externo y se procedió a su extracción con cesta

The ingestion of more than one magnet can cause multiple complications. Current protocols recommend endoscopic extraction if possible. We report a patient who swallowed two magnets and the endoscopic extraction technique. An 11-yearold boy presented at the Emergency Room after ingesting two small magnets, being asymptomatic. In the abdominal x-ray two radiopaque bodies were identified at the gastric chamber, apparently together. A gastroscopy was done in the operating room under general anaesthesia. To enable the extraction, a neodymium magnet was placed externally at the abdominal wall. In the endoscopic image, the two magnets were fixed to the anterior gastric wall. Once located, the neodymium magnet was removed and the two magnets were retrieved with an endoscopic basket.

Electromagnetic tracking-based ultrasound/computed tomography fusion imaging in dogs: preliminary application to ocular and periocular regions

In ultrasound/computed tomography (CT) fusion images, ultrasound allows visualization of the target in real time. CT provides a navigation for ultrasound scanning and improves the overview in areas of limited visualization with ultrasound. This study was performed to investigate the feasibility of ultrasound/CT fusion based on an electromagnetic tracking technique using external fiducial markers for canine ocular and periocular regions. In 7 Beagle dogs, contrast-enhanced CT images of the head were obtained with placing external fiducial markers over the frontal region and both sides of the forepaws of the dog. Ultrasonography was performed under a magnetic field by installing a position sensor in the linear probe, without changing the dog's position. The positions of the external fiducial markers were adjusted and matched, based on the CT images. The execution time of co-registration and the distance between the regions of interest and the co-registration points, the frontal bone, cornea, retina, and optic nerve, were estimated. Approximately 60% of external fiducial markers were properly recognized in all dogs. After adjustment, all external fiducial markers were precisely matched. The co-registration execution time was less than 1 min. The distances between the regions of interest and co-registration points were less than 3 mm in all dogs. The electromagnetic tracking technique using external fiducial markers was a simple and applicable method for fusion imaging of a canine head using real-time ultrasonography and CT. This technique can be useful for interventional procedures of retrobulbar and periorbital lesions.

Global Synchronization Index as an Indicator for Tracking Cognitive Function Changes in a Traumatic Brain Injury Patient: A Case Report

Traumatic brain injury is a main cause of long-term neurological disability, and many patients suffer from cognitive impairment for a lengthy period. Cognitive impairment is a fatal malady to that limits active rehabilitation, and functional recovery in patients with traumatic brain injury. In severe cases, it is impossible to assess cognitive function precisely, and severe cognitive impairment makes it difficult to establish a rehabilitation plan, as well as evaluate the course of rehabilitation. Evaluation of cognitive function is essential for establishing a rehabilitation plan, as well as evaluating the course of rehabilitation. We report a case of the analysis of electroencephalography with global synchronization index and low-resolution brain electromagnetic tomography applied, for evaluation of cognitive function that was difficult with conventional tests, due to severe cognitive impairment in a 77-year-old male patient that experienced traumatic brain injury.

Feasibility and Therapeutic Effects of a Novel Magnet-Based Device for Hand Rehabilitation: a Pilot Study

The purpose of this study was to investigate the feasibility and therapeutic effects of a novel concept hand rehabilitation device based on magnetics for subacute stroke patients with hand motor impairment. We developed an end effector type device that can induce various movements of the fingers in accordance with a magnetic field direction using electromagnets and permanent magnets. Subacute stroke patients with hand motor impairments were recruited and divided into two rehabilitation groups. Conventional rehabilitation therapies were also conducted equally in both groups. Active-assisted training of the affected hand was additionally administered for 30 minutes per day for 4 weeks using the developed equipment in the intervention group. Hand motor function and the activities of daily living were evaluated before and after the intervention. The Manual Function Test score significantly increased in the intervention group after 4 weeks of treatment (p = 0.039), and there was a significant difference in the degree of improvement between the two groups (p = 0.016). The scores of the motor Fugl-Meyer Assessment of the upper limb, the Wolf Motor Function Test score and time, and the motor Functional Independence Measure also improved in both groups (all p < 0.05). In addition, the patients in the intervention group showed greater improvements in these outcome measures than those in the control group did (all p < 0.05). An adjuvant rehabilitation therapy using a magnetic based device can be helpful to improve the hand motor function and activities of daily life in subacute stroke patients.

The Accuracy and Clinical Applicability of a Sensor Based Electromagnetic Non-fluoroscopic Catheter Tracking System

BACKGROUND AND OBJECTIVES: The differences between electromagnetic-based mapping (EM) and impedance-based mapping (IM) in 3D anatomical reconstruction have not been fully clarified. We aimed to investigate the anatomical accuracy between EM (MediGuide™) and IM (EnSite Velocity™) systems. METHODS: We investigated 15 consecutive patients (10 males, mean age 58±9 years) who underwent pulmonary veins (PVs) isolation for paroxysmal atrial fibrillation (PAF). Contrast-enhanced computed tomography (CT) image of the left atrium (LA) was acquired before ablation and the 3D geometry of the LA was constructed using EM during ablation procedure. We measured the 4 PV angles between the main trunk of each PV and the posterior LA after field scaling. Additionally, the posterior LA surface area was measured. The variables were compared to those of CT-based geometry. A control group of 40 patients who underwent conventional PVs isolation using IM were also evaluated. RESULTS: The actual and relative changes of EM and CT-based geometry in all PV angles and posterior LA were significantly smaller compared to those of IM and CT-based geometry. Intraclass correlation coefficient (ICC) between EM and CT-based geometry were 0.871 (right superior pulmonary vein [RSPV]), 0.887 (right inferior pulmonary vein [RIPV]), 0.853 (left superior pulmonary vein [LSPV]), 0.911 (left inferior pulmonary vein [LIPV]), and 0.833 (posterior LA). On the other hand, ICC between IM and CT-based geometry were 0.548 (RSPV), 0.639 (RIPV), 0.691 (LSPV), 0.706 (LIPV), and 0.568 (posterior LA). CONCLUSIONS: Image integration with EM enables high accurate visualization of cardiac anatomy compared to IM in PAF ablation.

Possible Effects of Radiofrequency Electromagnetic Field Exposure on Central Nerve System

Technological advances of mankind, through the development of electrical and communication technologies, have resulted in the exposure to artificial electromagnetic fields (EMF). Technological growth is expected to continue; as such, the amount of EMF exposure will continue to increase steadily. In particular, the use-time of smart phones, that have become a necessity for modern people, is steadily increasing. Social concerns and interest in the impact on the cranial nervous system are increased when considering the area where the mobile phone is used. However, before discussing possible effects of radiofrequency-electromagnetic field (RF-EMF) on the human body, several factors must be investigated about the influence of EMFs at the level of research using in vitro or animal models. Scientific studies on the mechanism of biological effects are also required. It has been found that RF-EMF can induce changes in central nervous system nerve cells, including neuronal cell apoptosis, changes in the function of the nerve myelin and ion channels; furthermore, RF-EMF act as a stress source in living creatures. The possible biological effects of RF-EMF exposure have not yet been proven, and there are insufficient data on biological hazards to provide a clear answer to possible health risks. Therefore, it is necessary to study the biological response to RF-EMF in consideration of the comprehensive exposure with regard to the use of various devices by individuals. In this review, we summarize the possible biological effects of RF-EMF exposure.

Design of Internal Grasper Based on Magnetic Anchoring Technique in Trocar-Less Laparoscopic Surgery / 中国医疗器械杂志

Laparoscopic surgery based on magnetic anchor technique has great potential for further minimally invasive surgery and good surgical field exposure, in which the internal grasper is the key factor. In this paper, an internal grasper based on magnetic anchor laparoscopic surgery is designed, which consists of three parts:target magnet, connection module and tissue forceps. The magnetic shield shell is used to wrap the magnetic core in the target magnet, which not only can increase the magnetic force in the working area, but also reduce the magnetic interference between the instruments, and the connecting module can flexibly adjust the length of the internal grasper. The special structure of tissue gripper can effectively reduce deputy injury and facilitate the replacement of clamp position. It has many advantages, such as ingenious design, easy processing, simple operation and wide range of application, which greatly increased its clinical application value.

Development and Application of Permanent Magnet Motor and Its Control in the Field of Artificial Blood Pump / 中国医疗器械杂志

Permanent magnet motor has been widely used in the field of artificial heart pump due to its high power density, high stability and easy control. In this paper, the development history and research progress of permanent magnet motor for blood pump were described. Firstly, the motors were classified according to their structures and application scenarios. And then, the measures taken by different types of motors to meet the corresponding performance requirements were introduced, and the specific application cases were given. After that, commonly used control algorithms of these motors were enumerated. What's more, the advantages and disadvantages of the control algorithms and their application emphasis were carefully explained. Finally, the paper was summarized in short.

Effects of Naloxegol on Gastrointestinal Transit and Colonic Fecal Volume in Healthy Participants Receiving Oxycodone

BACKGROUND/AIMS: Opioids cause gastrointestinal (GI) dysmotility, decrease gut secretion, and affect gut sphincters. Symptoms of opioid-induced bowel dysfunction may be alleviated by peripherally acting opioid antagonists like naloxegol, but detailed knowledge on GI effects of this drug is lacking. We hypothesized that naloxegol, compared to placebo, would reduce GI transit time and colonic fecal volume in opioid-treated healthy participants. METHODS: We conducted a randomized, double-blinded, single-center, 2-way cross-over study in 24 healthy males, randomized to a 6 day treatment period of oxycodone (15 mg twice a day) co-administered with either naloxegol (25 mg once a day) or matching placebo. Participants swallowed an electromagnetic capsule which determined GI transit times. Colonic fecal volume was quantified with magnetic resonance imaging both pre-treatment and post-treatment. RESULTS: Naloxegol reduced total GI transit time by 21% (56 hours vs 71 hours, P = 0.02) and colonic transit time by 23% (45 hours vs 59 hours, P < 0.01), compared to placebo. However, no difference in colonic fecal volume was found (818 mL vs 884 mL, P = 0.20). CONCLUSIONS: Short-term administration of naloxegol in healthy participants reverses the retardation of total GI and colonic transit induced by oxycodone. This supports the use of naloxegol in the treatment of GI side effects to opioid treatment, and add knowledge to the current understanding of mechanisms behind peripherally-acting opioid antagonists.

Colorectal Transit and Volume During Treatment With Prolonged-release Oxycodone/Naloxone Versus Oxycodone Plus Macrogol 3350

BACKGROUND/AIMS: Opioid-induced constipation (OIC) is the most common gastrointestinal (GI) side effect to opioid treatment. Opioid receptor antagonists against OIC have been introduced, but their efficacy has not been directly compared to conventional laxatives. Our aim was to compare symptoms and objective parameters of gut function in an experimental model of OIC during treatment with the opioid antagonist naloxone and oxycodone in prolonged-release (PR) formulation versus oxycodone plus macrogol 3350. METHODS: In this randomized, double-blind, crossover trial 20 healthy men received a 5-day treatment of combined PR oxycodone/naloxone or PR oxycodone plus macrogol 3350. Regional GI transit times and segmental colorectal transit were assessed with the Motilis 3D-Transit electromagnetic capsule system. Colorectal volumes were determined by MRI. OIC symptoms were assessed with validated questionnaires, along with stool frequency and consistency. RESULTS: Total colorectal volume did not change after 5 days’ treatment with PR oxycodone/naloxone (941 vs 1036 mL; P = 0.091), but increased significantly after PR oxycodone plus macrogol treatment (912 vs 1123 mL; P 0.05). The Patient Assessment of Constipation Symptom Questionnaire abdominal symptoms score was lower during PR oxycodone/naloxone compared to PR oxycodone plus macrogol (0.2 vs 3.2; P = 0.002). Stool frequency was lower during PR oxycodone/naloxone compared to PR oxycodone plus macrogol (4.2 vs 5.4; P = 0.035). CONCLUSIONS: PR oxycodone plus macrogol increases colorectal volume, but does not improve GI transit compared to PR oxycodone/naloxone. However, PR oxycodone/naloxone results in a lower abdominal symptom burden, despite higher stool frequency during macrogol treatment.

Optimization of Algerian Thymus fontanesii Boiss. & Reut Essential Oil Extraction by Electromagnetic Induction Heating

The present study deals with the determination of optimal values of operating parameters such as the temperature of heating, the mass of the plant material and the volume of water leading to the best yield of electromagnetic induction (EMI) heating extraction of Algerian Thymus fontanesii essential oil. After an appropriate choice of the three critical variables, eight experiments leaded to a mathematical model as a first-degree polynomial presenting the response function (yield) in the relation to the operating parameters. From the retained model, we were able to calculate the average response, the different effects and their interactions. The maximum of essential oil recovery percentage relative to the initial mass of plant material was 1.69%, and was obtained at (140 ℃, 250 g and 4.5 L). The chemical composition of the Algerian T. fontanesii essential oil under the obtained optimal conditions (140 ℃, 250 g and 4.5 L), determined by GC/MS and GC/FID, reveled of the presence of major components such as: carvacrol (70.6 ± 0.1%), followed by p-cymene (8.2 ± 0.2%).

Influence of electrocautery-induced electromagnetic interference on quantitative electroencephalographic monitoring of hypnosis during general anesthesia: comparison between the ADMS® and the BIS VISTATM / 대한마취과학회지

BACKGROUND: Hypnosis monitors analyze small-amplitude electrical signals transmitted from the brain that could be exposed to the electromagnetic field that occurs around the body during electrocautery (ECT). We investigated the influence of ECT on hypnosis monitoring during anesthesia. METHODS: We simultaneously monitored BIS and uCON during 50 gynecologic oncology surgeries. During the episodes of ECT, we compared the absolute difference (a-Diff) between the baseline index and the most deviated index after ECT over either 30–60 s (ECT30–60) or more than 60 s (ECT > 60) between the monitors. We also investigated the bias and the limits of agreement between the monitors. RESULTS: Between the two monitors, the a-Diff of ECT30–60 was 1.4 ± 1.1 for the BIS, which was significantly greater than 0.6 ± 0.9 for the uCON (P = 0.003), and the a-Diff of ECT > 60 was 16.5 ± 8.2 for the BIS, which was also significantly greater than 1.4 ± 1.3 for uCON (P 60 was significantly greater than that during ECT30–60 (P 60 (P = 0.056). The estimated bias between the monitors was 6.3 ± 9.8 and 95% limits agreement was –12.3 to 25.0. CONCLUSIONS: Prolonged ECT intervention might lead to spurious estimations of quantitative EEG indexes. Therefore, hypnosis should be clinically assessed in combination with scrutinized judgment of relevant clinical symptoms and signs for hypnosis.

Extracorporeal Shock Wave Therapy in Musculoskeletal Disorders / 대한정형외과학회잡지

The sources of shockwave generation include electrohydraulic, electromagnetic and piezoelectric principles, and extracorporeal shock wave therapy (ESWT) appears to have mechanical and biological effects on tissue healing. The application of ESWT to musculoskeletal disorders has been around for more than a decade and is used primarily in the treatment of calcific or non-calcific tendinitis of the shoulder, lateral and medial epicondylitis of the elbow, patellar tendinopathy, Achilles tendinitis or proximal plantar fasciitis of the heel, myofascial pain syndrome, etc. ESWT is also used in the treatment of delayed union or non-union of long bone fractures, avascular necrosis of the femoral head, and chronic diabetic ulcers. The vast majority of papers have reported positive and beneficial effects with few complications. The clinical application of ESWT has increased steadily. This article reviews the current status of ESWT in musculoskeletal disorders.