The dynamic triple peak impact factor in traumatic brain injury influences native protein structures in gray and white matter as measured with computational simulation

Abstract

Background: Traumatic brain injuries (TBIs) cause a substantial burden to the patient, relatives, and the society as a whole. Much experience and knowledge during the last two decades have improved the neurosurgical treatment as well as the outcome. However, there is still much debate on what actually happens when external kinetic energy is transferred to the head immediately after a TBI. Better knowledge about the cascades of mechanical events at the time of accident is a prerequisite to further reduce the burden in all categories and improve the neurosurgical care of TBI patients.

Methods: In the present study, we use the finite element modeling of the human brain to numerically simulate impact velocities of 10, 6, and 2 m/s to clarify some of the immediate consequences of the external kinetic energy transfer focusing on the gray (GM) and white matters (WM).

Results: The numerical simulation was focused on the external kinetic energy transfer with a level of 227·3 J reaching the head, intracranial pressure (ICP), strain energy density, 1st principal strain level, and their respective impacts on the brain tissue. The results show that, for a 10 m/s impact, a total internal potential energy of 208·6 J was absorbed, of which 14·3% (29·81 J) was absorbed by the scalp, 22·05% (46·0 J) by the outer compact bone, 17·12% (35·72 J) by the porous bone, 27·44% (57·23 J) by the inner compact bone, and 7·31% (15·24 J) by the facial bone. The rest of the internal potential energy was defined to reach the GM (3·6%, 7·51 J) and the WM 1·59% (3·31 J). Also, the ICP, strain energy density, and 1st principal strain levels, defined as the dynamic triple peak impact factor, influenced the GM and WM with their own impact peaks during the first 10 ms after the accident and were the highest for the 10 and 6 m/s impacts, while the 2 m/s impact had only a slight influence on the GM and WM structures.

Conclusions: The present study shows for the first time that following an impact of 10 m/s, 88·31% of the calculated external kinetic energy was absorbed by the external parts of the head before the remaining energy of 5·19% reached the GM and WM. GM absorbed about twice as much of the energy compared to the WM. It is suggested that the dynamic triple peak impact factor may have a profound effect on native protein structures in the cerebral metabolism after a TBI.     

计算机三维动画技术在创伤骨科教学课件中的应用及优势

结合实践介绍了在创伤骨科临床课件制作中三维动画技术的具体应用,分析了该技术在临床教学中的诸多优势,并探讨了三维动画技术在骨科医学教育中的应用原则。     

A simulator for percutaneous hepatic microwave thermal ablation under ultrasound guidance

The purpose of this study was to provide a simulation therapy environment for microwave thermal ablation (MWA) under the guidance of ultrasound, and to present an inexpensive and portable simulator built on real patient-based pre-operative computed tomography (CT) data. We established an experimental simulation system for teaching MWA and present the results of a preliminary evaluation of the simulator’s realism and utility for training. The system comprises physical elements of an electromagnetic tracking device and an abdominal phantom, and software elements providing three-dimensional (3D) image processing tools, real-time navigation functions and objective evaluation function module. Details of the novel aspects of this system are presented, including a portable electromagnetic tracking device, adoption of real patient-based pre-operative CT data of liver, operation simulation of MWA, and recording and playback of the operation simulation. Patients with liver cancer were selected for evaluation of the clinical application value of the experimental simulation system. A total of 50 consultant interventional radiologists and 20 specialist registrars in radiology rated the simulator’s hardware reality and overall ergonomics. Results show that the simulator system we describe can be used as a training tool for MWA. It enables training with real patient cases prior to surgery, and it can provide a realistic simulation of the actual procedure.     

Aural tuberculosis at the start of the 21st century. Literature review according to SWiM guidelines. Part 2: Treatment

ObjectivesSystematic review of the scientific literature dedicated to treatment modalities and results for aural tuberculosis published since the start of the 21^st century.Material and methodsSearch of the Medline, Cochrane and Embase databases for the period 2000 - 2020. Selection of articles in English, French and Spanish devoted to clinical cases and series documenting treatment of auricular tuberculosis. Extraction of data on pre-established files documenting treatment modalities and results. Reading of articles by two authors. Analysis performed according to SWiM guidelines, evaluating cure, tuberculosis-related death, treatment-related complications, improvement in facial palsy, and hearing sequelae rates.ResultsOne hundred and twenty eight articles: 118 case reports (159 patients) and 10 cohorts (177 patients) from 42 countries were analyzed. Female/male sex ratio was 1.2 with ages ranging from 1 month to 87 years. Medical treatment consisted in 5 to 24 months’ antitubercular antibiotic treatment using 2 to 8 antibiotics. Mastoidectomy, tympanoplasty and facial nerve decompression were associated to medical treatment in 64.7%, 17.4% and 6.2% of cases, respectively. Overall rates of cure, death, treatment-related complications, facial sequelae and hearing sequelae were 96.8%, 2%, 9.5%, 35.8% and 75.5%. In case reports, BCG vaccination did not appear to protect against facial palsy and severe intracranial complications (P > 0.6). There was no significant correlation (P > 0.3) between death and the clinical variables tested, and facial nerve decompression did not appear to influence outcome for facial function (P = 0.4).ConclusionMedical treatment is very effective but not without risk of death, complications and sequelae. It is the same as for pulmonary tuberculosis. Indications for and benefit of major auricular surgery during medical treatment deserve further studies.     

Modeling the Recovery of Elective Waiting Lists Following COVID-19: Scenario Projections for England

ObjectivesA significant indirect impact of COVID-19 has been the increasing elective waiting times observed in many countries. In England’s National Health Service, the waiting list has grown from 4.4 million in February 2020 to 5.7 million by August 2021. The objective of this study was to estimate the trajectory of future waiting list size and waiting times up to December 2025.MethodsA scenario analysis was performed using computer simulation and publicly available data as of November 2021. Future demand assumed a phased return of various proportions (0%, 25%, 50%, and 75%) of the estimated 7.1 million referrals “missed” during the pandemic. Future capacity assumed 90%, 100%, and 110% of that provided in the 12 months immediately before the pandemic.ResultsAs a worst-case scenario, the waiting list would reach 13.6 million (95% confidence interval 12.4-15.6 million) by Autumn 2022, if 75% of missed referrals returned and only 90% of prepandemic capacity could be achieved. The proportion of patients waiting under 18 weeks would reduce from 67.6% in August 2021 to 42.2% (37.4%-46.2%) with the number waiting over 52 weeks reaching 1.6 million (0.8-3.1 million) by Summer 2023. At this time, 29.0% (21.3%-36.8%) of patients would be leaving the waiting list before treatment. Waiting lists would remain pressured under even the most optimistic of scenarios considered, with 18-week performance struggling to maintain 60%.ConclusionsThis study reveals the long-term challenge for the National Health Service in recovering elective waiting lists and potential implications for patient outcomes and experience.     

隐性思想政治教育在医务工作规范化管理中的重要作用

隐性思想政治教育具有方式的多样性、过程的隐蔽性、内容的丰富性等特征，从而可以在医务工作规范化管理中发挥极其重要的作用，实践中要从明确职责、整合力量、加大投入、科学规划等方面着手促进这种作用的发挥。