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Objective:To analyze the stability of different internal fixation methods for zygomaticomaxillary complex fracture using finite element biomechanical analysis and to provide a quantitative basis for the option of optimal internal fixation methods.Methods:One patient with zygomaticomaxillary complex ZMC fracture (Zingg B type) was enrolled from the Second Hospital of Dalian Medical University in October 2016.The zygomaticofrontal suture and the inferior orbital rim were fixed during the surgery, and the postoperative function was well recovered with no mouth opening restriction, diplopia or implant displacement, and had a symmetrical facial appearance.The preoperative orbital CT images were collected.The normal craniofacial bones finite element model (FEM/intact) was reconstructed through Mimics, Geomagic, Solidworks and Abaqus softwares based on the non-fractured side and verified.Based on the verified model, the segmentation and assembling was performed according to the fracture location, and the internal fixation models were established according to the methods of surgery, including fixed zygomaticofrontal suture model (FEM/ZFS), fixed inferior orbital rim model(FEM/IOR), fixed zygomaticofrontal suture and inferior orbital rim model (FEM/ZFS+ IOR), fixed ZFS and IOR and zygomaticomaxillary suture model (FEM/ZFS+ IOR+ ZMS). The masseter muscle strength was applied to the model.The stress and displacement were analyzed and the rotation angle of zygoma was calculated to compare the stability of different operative methods.The postoperative model (FEM/post) was established according to the actual operative method and was compared with FEM/ZFS+ IOR.This study protocol was approved by the Ethic Committee of The Second Hospital of Dalian Medical University (2020-33), and written informed consent was obtained from the subject before entering the study.Results:The established FEM/intact had a realistic appearance and good geometric similarity, and the validity and accuracy of model was verified.In the FEM/ZFS+ IOR and FEM/ZFS+ IOR+ ZMS, the maximal stress of the titanium plate was 396 MPa and 426 MPa, respectively, which was lower than the yield strength 483 MPa of pure titanium, and the maximal displacement of the fracture line was 0.10 mm and 0.06 mm, respectively, which was both≤0.1 mm, and the rotation angle of zygoma was both<2°.In the FEM/ZFS and FEM/IOR, the maximal stress of the titanium plate was 730 MPa and 501 MPa, respectively, which was higher than the yield strength of pure titanium; the maximal displacement of fracture line was 0.27 mm and 0.15 mm, respectively, which was >0.1 mm, and the rotation angle of zygoma was <2°.The results of FEM/post were consistent with those of FEM/ZFS+ IOR.Conclusions:The finite element analysis can perform digital analysis and evaluation of the stability of different internal fixation methods before surgery, which is available for the selecting of the optimal fixation methods.Finite element analysis can provide an objective quantitative basis for the precise treatment of zygomaticomaxillary complex fractures.
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Critical ultrasonography(CUS) is different from the traditional diagnostic ultrasound,the examiner and interpreter of the image are critical care medicine physicians.The core content of CUS is to evaluate the pathophysiological changes of organs and systems and etiology changes.With the idea of critical care medicine as the soul,it can integrate the above information and clinical information,bedside real-time diagnosis and titration treatment,and evaluate the therapeutic effect so as to improve the outcome.CUS is a traditional technique which is applied as a new application method.The consensus of experts on critical ultrasonography in China released in 2016 put forward consensus suggestions on the concept,implementation and application of CUS.It should be further emphasized that the accurate and objective assessment and implementation of CUS requires the standardization of ultrasound image acquisition and the need to establish a CUS procedure.At the same time,the standardized training for CUS accepted by critical care medicine physicians requires the application of technical specifications,and the establishment of technical specifications is the basis for the quality control and continuous improvement of CUS.Chinese Critical Ultrasound Study Group and Critical Hemodynamic Therapy Collabration Group,based on the rich experience of clinical practice in critical care and research,combined with the essence of CUS,to learn the traditional ultrasonic essence,established the clinical application technical specifications of CUS,including in five parts:basic view and relevant indicators to obtain in CUS;basic norms for viscera organ assessment and special assessment;standardized processes and systematic inspection programs;examples of CUS applications;CUS training and the application of qualification certification.The establishment of applied technology standard is helpful for standardized training and clinical correct implementation.It is helpful for clinical evaluation and correct guidance treatment,and is also helpful for quality control and continuous improvement of CUS application.
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Objective To investigate the accuracy and efficiency of hand-held echocardiography (VSCAN) used by intensivist for the diagnosis and treatment decisions in emergency consultation for patients getting worse at risk of life-threatening setting in non-ICU ward.Methods A prospective study in acutely deteriorated patients needed the intensivist for emergency consultation in general wards was carried out.The consultation process was executed as follows:(1) The intensivist established an initial diagnosis based on medical history,physical examination and laboratory findings,and assessed the hemodynamics and the cause of acute respiratory failure and cardiac arrest according the documented information.The data recorded as control group (Pre-VSCAN) for comparison with the later available data in subsequent analysis.(2) Problem-based ultrasound examination was performed with VSCAN.For patients suffered cardiac arrest,the FEEL protocol was used to find the potential cause of cardiac arrest such as pericardial tamponade and massive pulmonary embolism screened.For the other patients,a simplified eFATE or BLUE-plus protocols were used based on clinical requirement.With the findings of ultrasound examination the intensivist established an final diagnosis and identified the hemodynamics and the lung pathologies.The consultation advice was then provided to the attending doctors of the patient.The intensivist kept the records of echo results,final diagnosis and consultation advice as data of study group data (Post-VSCAN).The response of the treatment and outcome were followed up.Two attending ICU doctors analyzed these data and judged the correctness of Pre-VSCAN and Post-VSCAN based on the response to treatment and the outcome.Results Ninety patients were finally included in statistical analysis.Sixteen (17.8％) cases,40 (44.4％) cases,29 (32.2％) cases and 5 (5.6％) were consulted for acute circulation dysfunction,acute respiratory failure,both reasons and cardiac arrest,respectively.Compared to pre-VSCAN,VSCAN verification can significantly improve the accuracy of the diagnosis (81.1％ vs.58.9％,P =0.001),assessment of hemodynamics (78.3％ vs.52.2％,P =0.009) and can find more accurate judgment of acute respiratory failure (71.0％ vs.43.5％,P =0.001).Conclusion The hand-held echocardiography used by intensivist is valuable for the diagnosis and the assessment of cardiopulmonary status in case of request for emergency consultation in general wards.
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Objective To provide epidemiological data as a reference for the coming research and clinical practice by analyzing the problem based critical care ultrasound (CCUS) examination database in Department of Critical Care Medicine,West China Hospital, Sichuan University. Methods A retrospective study of the database was performed. The clinical problems prompting the CCUS examination were classified, the ultrasonnic findings representing the pathophysiological changes were collected and gathered into categories, and the pathophysiological etiology for each classification of clinical problems was stated after referring to the clinical information. Results In the 135 cases with a mean age of (51±18) years, 386 times of problems based examinations were performed (2.85 times per patient). The problems prompting the examinations were acute circulatory dysfunction (271 times, 70.2%), acute respiratory dysfunction (34 times, 8.8%), acute circulatory dysfunction combined with acute respiratory dysfunction (76 times, 19.7%), and suspected diaphragm disorder and others (5 times, 1.2%). In the 347 times of examination for acute circulatory dysfunction, the pathophysiological changes discovered by the CCUS examination included hypovolemia (55 times, 15.9%), hypervolemia (85 times, 24.5%), decreased systemic vascular resistance index (22 times, 6.3%), and increased right ventricular (RV) afterload (15 times, 4.3%). In the 246 times of examination for cardiac dysfunction, the underlying etiology detected included left ventricular (LV) systolic dysfunction (31 times, 12.6%), LV diastolic dysfunction (108 times, 43.9%), LV systolic dysfunction associated with diastolic dysfunction (49 times, 19.9%), RV dysfunction (23 times, 9.4%), and whole heart failure (35 times, 14.2%). Acute respiratory disorders was identified 110 times in total, which consisted of lung consolidation (40 times, 36.4%), diffuse ultrasonic interstitial syndrome (DIS; 27 times, 24.5%), consolidation associated with DIS (18 times, 16.4%), focal interstitial syndrome (17 times, 14.6%), and others (9 times, 8.2%). Causes of deterioration of the cases were cardiogenic pulmonary edema, diastolic dysfunction, RV failure, acute valve insult or chronic valve insufficiency and so on. Conclusions The main problems prompting the CCUS examinations are acute circulatory dysfunction and acute respiratory dysfunction. CCUS examination can provide physicians with valuable information on the full picture of the pathophysiology characteristics of hemodynamics and lung pathology to help diagnose the causes of the deterioration and guide clinical treatment.