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Prosthetic polymeric heart valves (PHVs) have the potential to overcome the inherent material and design limitations of traditional valves in the treatment of valvular heart disease; however, their durability remains limited. Optimal design of the valve structure is necessary to improve their durability. This study aimed to enhance the fatigue resistance of PHVs by improving the stress distribution. Iterative subregional thickening of the leaflets was used, and the mechanical stress distribution and hemodynamics of these polymeric tri-leaflet valves were characterized using a fluid-structure interaction approach. Subregional thickening led to a reduction in stress concentration on the leaflet, with the effective orifice area still meeting ISO 5840-3 and the regurgitant volume achieving a similar value to those in previous studies. The maximum stress in the final iteration was reduced by 28% compared with that of the prototype. The proposed method shows potential for analyzing the stress distribution and hemodynamic performance of subregional thickened valves and can further improve the durability of PHVs.
Subject(s)
Heart Valve Prosthesis , Prosthesis Design , Hemodynamics , Computer Simulation , Aortic Valve , Stress, Mechanical , Polymers , Models, CardiovascularABSTRACT
ObjectiveTo explore the application of Brain and Spinal Injury Center (BASIC) score in evaluation of traumatic cervical spinal cord injury. MethodsFrom January, 2015 to December, 2021, 175 patients with traumatic cervical spinal cord injury in Beijing Bo'ai Hospital were analyzed. Gender, age, cause of injury, injury mechanism and American Spinal Injury Association Impairment Scale (AIS) grade were collected. The sagittal and axial T2 weighted imaging (T2WI) of the patients were evaluated with BASIC score, single/multi-segment injury, and with/without intramedullary hemorrhage. According to the injury mechanism, the patients were divided into two groups: with fracture/fracture dislocation (n = 92) and without fracture and dislocation (n = 83). The baseline demographic indicators and T2WI evaluation indicators were compared between the two groups, and the relationship between AIS grade and BASIC score, intramedullary hemorrhage, single/multi-segment injury were investigated. ResultsThere were significant differences in gender, age and AIS grade, BASIC score, and the rates of inntramedullary hemorrhage and single segment injury of T2WI between two groups (t = -10.276, χ2 > 8.703, P < 0.01); however, no difference was found in the cause of injury (P > 0.05). The AIS grade was significantly correlated with the BASIC score (r = 0.790, P < 0.001). There was significant difference in AIS grade between intramedullary hemorrhage or not, and single/multi-segment injury (χ2 > 5.516, P < 0.05). ConclusionThe BASIC score of T2WI is a predictor of the severity of spinal cord injury after traumatic cervical spinal cord injury, and is different with the injury mechanisms.
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ObjectiveTo observe the characteristics of gait symmetry and its influencing factors in patients with incomplete spinal cord injury (ISCI). MethodsFrom May, 2018 to November, 2021, 34 patients with ISCI in Beijing Bo'ai Hospital were divided into symmetrical injury of lower limb (SI) group and asymmetrical injury of lower limb (ASI) group according to the lower extremities motor score (LEMS). Three dimensional motion acquisition system and plantar pressure acquisition system were used for gait test. The symmetry indexes of step length, stance time and swing time were caculated. ResultsThe symmetry indexes of step length, stance time and swing time were significant lower in SI group than in ASI group (|t| > 2.619, P < 0.01). Stance time and swing time significantly correlated to the difference of bilateral LEMS in ASI group (r > 0.468, P < 0.01). Discriminant analysis showed that gait parameter equations were different for patients with different symmetry of lower limb injuries. ConclusionThe symmetry of lower limb motor function impacts gait symmetry for patients with ISCI, especially the difference value of bilateral total LEMS. Gait parameters can be used to determine the symmetry of lower limb injury in patients with ISCI.
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ObjectiveTo investigate the changes of bone mineral density of distal femur and proximal tibia in patients with spinal cord injury. MethodsNine inpatients with spinal cord injury in Beijing Bo'ai Hospital for rehabilitation from November, 2018 to January, 2021 were recruited. The bone mineral density of distal femur, proximal tibia, total hip and femoral neck at admission and six months after admission was measured. ResultsCompared with the results of admission, the bone mineral density of distal femur, proximal tibia, total hip and femoral neck decreased significantly six months after admission (∣Z∣ > 2.265, P < 0.01). The percentage of decreased bone mineral density in the femoral neck was inversely correlated with the lower extremity movement score at the second measurement (r = -0.515, P = 0.035). ConclusionWithin one year after the onset of spinal cord injury, the bone mineral density of distal femur and proximal tibia decreases.
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The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to significant public health, economic and social problems. Development of effective vaccines is still a priority to contain the virus and end the global pandemic. In this study, we reported that ReCOV, a recombinant trimeric NTD and RBD two-component SARS-CoV-2 subunit vaccine adjuvanted with BFA03 (an AS03-like squalene adjuvant), induced high levels of neutralizing antibodies against SARS-CoV-2 and the circulating variants in mice, rabbits and rhesus macaques. Notably, two-dose immunizations of ReCOV provided complete protection against challenge with SARS-CoV-2 in hACE2 transgenic mice and rhesus macaques, without observable antibody-dependent enhancement of infection. These results support further clinical development of ReCOV and the vaccine is currently being evaluated in a phase I clinical trial in New Zealand (NCT04818801).
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@#Objective To explore the prevention for hip dysplasia after pediatric spinal cord injury. Methods From March, 2017, the families of 47 children with spinal cord injury accepted education for preventing improper posture of sitting and sleeping and other interventions, and 23 of them were followed up for three months or more. Results New hip dislocation was found in one child, and 18 children developed almost normally in hip, the other four children with old hip dislocation did not worsen.Conclusion Intervention in time may prevent the hip dislocation in children with spinal cord injury.
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Spinal cord injury is a catastrophic injury causing lifelong severe disabilities, and poses a great burden to the individuals, families and society. In order to promote the standardization in treatment of traumatic spinal cord injury, the consensus on the evaluation, treatment and rehabilitation of traumatic spinal cord injury was suggested by experts, who came from authoritative multicenter in China. The expert consensus, which formed a standardization process from the first aid clinical treatment to rehabilitation of spinal cord injury, shall give a better practical guide for clinic and rehabilitation physicians.
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As the manual muscle testing is not sensitive enough to reflect the change of muscle strength, more and more people begin to use isokinetic dynamometry and handheld dynamometer for quantitative tests of muscle strength measurement. This paper briefly introduced the history of clinical approaches of muscle strength measurement, compared the advantages and disadvantages of various quantitative mus-cle strength testing, on which the specific techniques of clinical muscle strength measurement were discussed.
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Objective To survey the survival status, functional status, marital status and the present situation of the survival patients with spinal cord injury 40 years after Tangshan earthquake. Methods From February to May, 2016, a total of 216 patients with spinal cord injury were surveyed with questionnaire, in which 139 cases lived centralized and 77 cases lived scattered. The questionnaire was self-designed and included eleven items and 51 questions, which related to ability of daily life, marital status, employment status and socioeconomic status and so on. Results A total of 960 (25.15%) patients with spinal cord injury survived 40 years after Tangshan earthquake. In 216 surveyed pa-tients, the employment rate was 9.3%, the married rate was 53.2%, and 44.9%earned less than 500 yuan every month. The incidence was 25.9%for pressure score, 50.50%for neuralgia (severe pain accounted for 23.51%), and 19.40%for urinary tract stones. 56%of patients could take their own basic self-care. Conclusion There were many problems such as high complication rate, low employment rate and poor economic condition in the spinal cord injury group 40 years after Tangshan earthquake.
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Objective To retrospectively analyze the lower extremity deep vein thrombosis prevention in patients with spinal cord injury (SCI). Methods A total of 115 SCI patients in our department from April to May, 2015 were included. The clinical symptoms, lower limb deep vein ultrasonic testing, laboratory examination were collected to analyze the occurrence, prevention measures, the thrombus location and management of deep venous thrombosis (DVT) in lower limbs. Results Forty-three patients had thromboprophylaxis in other hospitals before admission, and 105 patients in our department after admission, in which, nine cases were with clinical symptoms in other hospitals and three cases in our department. No pulmonary embolism occurred in them. There was no significant difference in most laboratory index-es between patients with DVT and without DVT in lower limbs (P>0.05). Five patients were with DVT in lower limbs in 43 patients who had thromboprophylaxis, and four cases in 72 patients who did not have thromboprophylaxis. No relationship was found between thrombo-prophylaxis and DVT in lower limbs (χ2=0.663, P=0.415). Five patients were with DVT in lower limbs in 53 patients with complete SCI, and four cases in 59 patients with incomplete SCI. No relationship was found between the severity of SCI and DVT in lower limbs in other hospitals (χ2=0.028, P=0.867). Conclusion DVT in lower limbs could be also occurred in patients who accepted thromboprophylaxis. Labo-ratory indexes are inadequate for the prediction and diagnosis specificity of DVT in lower limbs.
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Objective To compare the apparent diffusion coefficients (ADC) between healthy people and patients with early cervical spi-nal cord injury (SCI). Methods 18 patients with early cervical SCI and 5 healthy controls were examined with MRI T1WI, T2WI and DWI, and the ADC values and ADC maps were obtained. Results and Conclusion ADC values were less in the patients than in the healthy con-trols, and the cut-off point was 800.0×10-6 mm2/s. ADC values also reduced in some patients without obvious abnormal MRI finds.
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Objective To develop a comprehensive rehabilitation information system based on browser/server (B/S) structure, to imple-ment entry, retrieval, statistics, analysis, browsing and exhibition of electronic data in rehabilitation medicine. Methods Based on the system-atic analysis of the rehabilitation work flow and the data need to be disposed, a distributed database system was established, and some mod-ules of applications were developed, such as treatment planning, efficacy evaluation, outcome prediction and performance appraisal. Results The simplified version of Hydrotherapy Comprehensive Rehabilitation Information System was initially developed based on Ruby on Ralis framework and PostgreSQL database, and tested in the local area network of China Rehabilitation Research Center. Conclusion The compre-hensive rehabilitation information system based on B/S structure is feasible, and shows the potentialities to improve the team work in reha-bilitation based on internet.
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Objective To investigate the correlation between Semmes-Weinstein monofilament test and light touch exam of international standard for spinal cord injury (SCI). Methods 84 inpatients with SCI were assessed with Semmes-Weinstein monofilament test and light touch exam of international standard to determine the SCI level. The results were recorded as right-side and left-side of the body respective-ly. Results The normal tactual level of monofilament test and the normal light touch level of International Standard of Spinal Cord Injury (ISSCI) was consistent in 36%result to the unilateral level of SCI. For the 45 cases with ASIA A injury, 71%of the key points below the SCI level lost the tactual sensation in monofilament test, and 84%lost in light touch exam of ISSCI. Conclusion The result of monofilament test is poorly consistent with light touch exam of SCI, which may result from tactile sensitization after SCI. It is recommended to combine these exam in practices.
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@#Objective To investigate the correlation between Semmes-Weinstein monofilament test and light touch exam of international standard for spinal cord injury (SCI). Methods 84 inpatients with SCI were assessed with Semmes-Weinstein monofilament test and light touch exam of international standard to determine the SCI level. The results were recorded as right-side and left-side of the body respectively. Results The normal tactual level of monofilament test and the normal light touch level of International Standard of Spinal Cord Injury (ISSCI) was consistent in 36% result to the unilateral level of SCI. For the 45 cases with ASIA A injury, 71% of the key points below the SCI level lost the tactual sensation in monofilament test, and 84% lost in light touch exam of ISSCI. Conclusion The result of monofilament test is poorly consistent with light touch exam of SCI, which may result from tactile sensitization after SCI. It is recommended to combine these exam in practices.
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@#Objective To compare the apparent diffusion coefficients (ADC) between healthy people and patients with early cervical spi nal cord injury (SCI). Methods 18 patients with early cervical SCI and 5 healthy controls were examined with MRI T1WI, T2WI and DWI, and the ADC values and ADC maps were obtained. Results and Conclusion ADC values were less in the patients than in the healthy con trols, and the cut-off point was 800.0×10-6 mm2/s. ADC values also reduced in some patients without obvious abnormal MRI finds.
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@#Objective To study the modification of the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) worksheet (2013 version) and the significance for clinical practice. Methods The latest English version of ISNCSCI worksheet- 2013 was compared with the previous version to find the advantages of current version and analyze its significance according to the experience from using the worksheet-2011. Results 11 modifications were found in ISNCSCI-2013, in which some were just discrimination, some were for emphasis, and the others were detailing. Conclusion The ASIA International Standards Committee made prudent modifications according to the practical experience of the ISNCSCI-2011 to make the worksheet more scientific and clear for recording. The modification will be more beneficial to record and determine the evaluation results of neurological examination of spinal cord injury in clinical practice.
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@#Study design Survey of expert opinion, feedback and final consensus. Objective To describe the development and the variables included in the International Spinal Cord Injury (SCI) Spinal Interventions and Surgical Procedures Basic Data set. Setting International working group. Methods A committee of experts was established to select and define data elements. The data set was then disseminated to the appropriate committees and organizations for comments. All suggested revisions were considered and both the International Spinal Cord Society and the American Spinal Injury Association endorsed the final version. Results The data set consists of nine variables: (1) Intervention/ Procedure Date and start time (2) Non-surgical bed rest and external immobilization, (3) Spinal intervention-closed manipulation and/or reduction of spinal elements, (4) Surgical procedure-approach, (5) Date and time of the completion of the intervention or surgical closure; (6) Surgical procedure-open reduction, (7) Surgical procedure-direct decompression of neural elements, and (8 and 9) Surgical procedure- stabilization and fusion (spinal segment number and level). All variables are coded using numbers or characters. Each spinal intervention and procedure is coded (variables 1 through 7) and the spinal segment level is described (variables 8 and 9). Sample clinical cases were developed to illustrate how to complete it. Conclusion The International SCI Spinal Interventions and Surgical Procedures Basic Data Set was developed to facilitate comparisons of spinal interventions and surgical procedures among studies, centers and countries.
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Objective To investigate the application of International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) in China. Methods A retrospective review was performed and the articles were identified in Chinese National Knowledge Infra-structure (CNKI), Wanfang data and CqVip data from January 2012 to January 2015. The articles were searched by words Spinal Cord Inju-ry, Paraplegia and Tetraplegia. Results The usage rate of ISNCSCI was 46.6%in domestic, and they were 60.7%, 47.8%and 35.3%in de-partments of rehabilitation, spinal surgery and orthopedics, respectively. Conclusion ISNCSCI is not widely used in spinal cord injury re-search in China, so it is important to raise the awareness and promote the use of ISNCSCI.
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Objective To study the modification of the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) worksheet (2013 version) and the significance for clinical practice. Methods The latest English version of ISNCSCI work-sheet-2013 was compared with the previous version to find the advantages of current version and analyze its significance according to the ex-perience from using the worksheet-2011. Results 11 modifications were found in ISNCSCI-2013, in which some were just discrimination, some were for emphasis, and the others were detailing. Conclusion The ASIA International Standards Committee made prudent modifica-tions according to the practical experience of the ISNCSCI-2011 to make the worksheet more scientific and clear for recording. The modifi-cation will be more beneficial to record and determine the evaluation results of neurological examination of spinal cord injury in clinical practice.
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@#Study design Survey of expert opinion, feedback and final consensus. Objective To describe the development and the variables included in the International Spinal Cord Injury (SCI) Spinal Interventions and Surgical Procedures Basic Data set. Setting International working group. Methods A committee of experts was established to select and define data elements. The data set was then disseminated to the appropriate committees and organizations for comments. All suggested revisions were considered and both the International Spinal Cord Society and the American Spinal Injury Association endorsed the final version. Results The data set consists of nine variables: (1) Intervention/ Procedure Date and start time (2) Non-surgical bed rest and external immobilization, (3) Spinal intervention-closed manipulation and/or reduction of spinal elements, (4) Surgical procedure-approach, (5) Date and time of the completion of the intervention or surgical closure; (6) Surgical procedure-open reduction, (7) Surgical procedure-direct decompression of neural elements, and (8 and 9) Surgical procedure- stabilization and fusion (spinal segment number and level). All variables are coded using numbers or characters. Each spinal intervention and procedure is coded (variables 1 through 7) and the spinal segment level is described (variables 8 and 9). Sample clinical cases were developed to illustrate how to complete it. Conclusion The International SCI Spinal Interventions and Surgical Procedures Basic Data Set was developed to facilitate comparisons of spinal interventions and surgical procedures among studies, centers and countries.
