Effects of Fixed-Point Lateral Flexion and Rotation Manipulation on Intervertebral Foramina Morphology of Cervical Spondylotic Radiculopathy / 医用生物力学

Objective To analyze the changes in morphology of intervertebral foramina in patients with cervical spondylotic radiculopathy (CSR) treated with fixedpoint lateral flexion and rotation manipulation based on three-dimensional (3D) reconstruction technology, so as to provide references for the effectiveness of manipulation treatment. MethodsForty patients with CSR were treated with fixed point lateral flexion and rotation manipulation once every other day for a total of 7 times and 2 weeks as a course of treatment. CT data of the patients before and after treatment were analyzed by using multifunctional CT, Mimics 21.0, Geomagic and SolidWorks 2017. The area of the intervertebral foramen, anterior and posterior diameter of the intervertebral foramen, upper and lower diameter of the intervertebral foramen were measured before and after treatment, as well as the infrared thermal imaging temperature differences of the bilateral neck and shoulder, front and back of the upper limb, and the VAS scores of the patients were observed before treatment, 7 d after treatment, 14 d after treatment and 1 month follow-up. Results Foraminal area, anterior and posterior diameters, upper and lower diameters of 40 patients were improved after treatment, and the temperature differences of infrared thermal imaging of patients before and after treatment were statistically significant. The VAS score of the patients decreased progressively. Conclusions Fixed point lateral flexion manipulation can significantly improve the shape of the intervertebral foramen in patients with CSR, so as to achieve the treatment purpose of relieving nerve compression.

Hemodynamic Analysis on Proximal End of the Aortic Dissection with Different Rupture Shapes / 医用生物力学

Objective To explore hemodynamic performance of the aortic dissection after lesions, so as to provide a more scientific basis for patient treatment. Methods Based on computed tomography angiography (CTA) image data from a patient with complex Stanford B-type aortic dissection, the personalized aortic dissection models with different rupture shapes (H-type, O-type, and V-type) at proximal end of the aortic dissection were established. Combined with computational fluid dynamics (CFD) and morphological analysis method, distributions of the velocity at rupture section, the blood flow, the wall pressure and the wall shear stress (WSS) were analyzed. Results The flow velocity, the highest pressure difference and the WSS proportion at entrance of the H-shaped rupture showed larger hemodynamic parameters than those of the other two types. The risk of dissection rupture for type H was the largest, while type V was in the middle, and type O was the smallest. Conclusions This study provides an effective reference for further numerical analysis the cases and formulation of treatment plans.

Application of Three-dimensional Reconstruction in Single Utility-port Thoracoscopic Segmentectomy for Early Stage Non-small Cell Lung Cancer: A Propensity Score-matched Analysis / 肿瘤防治研究

Objective To evaluate the clinical value of 3D reconstruction in the single utility-port thoracoscopic segmentectomy of early stage NSCLC by propensity score matching (PSM). Methods We retrospectively analyzed clinical data of 150 early stage NSCLC patients undergoing single utility-port thoracoscopic segmentectomy. The patients were divided into reconstruction group (n=58) and non-reconstruction group (n=92) according to 3D reconstruction. PSM was performed on two groups to compare perioperative outcomes. Results Procedures were successfully completed on all patients, without perioperative death. In each group, 43 patients were successfully matched after PSM on the basis of 8 confounding factors, age, gender, smoking status, BMI, maximum tumor diameter on CT, tumor location, % FEV1 and type of planned segmentectomy. After PSM, in complex segmentectomy, the patients in the reconstruction group had shorter operation time (155.77±30.17 vs. 212.94±66.49min, P < 0.001) and less blood loss (46.00±25.94 vs. 88.79±68.36ml, P=0.002), compared with the non- reconstruction group. Conclusion Preoperative 3D reconstruction could help improve the efficiency of single utility-port thoracoscopic surgery for complex segmentectomy and reduce intraoperative bleeding.

Research Method for Numerical Simulation on Upper Respiratory Tract Airway State Based on 3D Printing and CT Reconstruction / 医用生物力学

Objective To establish a comprehensive method combining physical model experiment and numerical simulation for studying airflow state of upper respiratory tract. Methods Based on CT medical images published online, a three-dimensional (3D) model of human upper respiratory tract was reconstructed. Based on 3D printing technology, an experimental model of the upper respiratory tract was established and the flow process of respiration was measured. A numerical simulation model was created based on the meshing of upper respiratory tract model and the turbulent Realizable k-ε model. Results Firstly, the result of numerical simulation was compared with the experimental conditions, and good agreement was achieved. The numerical simulation results showed that the airflow in respiratory process was in a parabolic shape; the distribution of flow field, pressure on wall and vortex structure were different between inspiratory and expiratory phases; there were air residues in the upper and lower nasal passages during the respiratory exchange process. In addition, the effects of airflow on physiological environment of the upper respiratory tract were preliminarily analyzed through the steak line, pressure field and vortex structure distribution. Conclusions The method proposed in this paper has the characteristics of pertinence, rapidity and accuracy, which gives full play to the advantages of reliable physical experiments and fine numerical simulation, and is applicable for studying different problems of the upper respiratory tract in different cases, with a high value for personalized diagnosis and treatment in clinic.

Finite Element Simulation of AnyBody-Based Musculoskeletal Multi-Body Dynamics / 医用生物力学

Objective To investigate the method of modeling, finite element modeling and AnyBody musculoskeletal multi-body dynamics simulation technique analyze the biomechanics of clinical orthopaedic surgery. Methods The AnyBody software was used to establish the musculoskeletal motor model of the individualized upper limbs according to the height, weight and CT data of the volunteers. The flexion motion of the elbow in normal people was simulated, and the muscle force, joint force, torque, constraint condition of the humerus during the flexion movement were derived and used as the boundary conditions of finite element analysis.Then, the 3D reconstruction was conducted in the MIMICS software based on CT data. In the Geomagic Studio software, the humeral curved surface and position coordinate matching were completed, and grid division and material assignment were done in the HyperMesh software. Finally, the 3D reconstruction for finite element model of the humerus was introduced into ABAQUS software. The boundary condition data derived from the AnyBody software were applied and the stress calculation analysis was performed. Results The results of the stress and displacement of the humerus during elbow flexion motion were calculated in the ABAQUS software. The maximum stress and displacement of the humerus were 0.76 MPa and 20 μm when flexion of the elbow joint was about 90°. Conclusions A continuous dynamic analysis of humeral stress and displacement during elbow flexion motion was realized, which was more consistent with the requirements of human physiological anatomy and could provide an efficient analysis platform and a new way for studying clinical orthopedic problems.

Numerical simulation of unilateral mandibular distraction osteogenesis / 医用生物力学

Objective To study the law of shape changes of mandiblular distraction osteogenesis in the patient with hemifacial microsomia(HFM) and compare the results with the real effect on the patient by establishing the models of mandibular and masticatory muscles, and to put forward some good suggestions on procedures of treating patients diagnosed as HFM and related cases. Methods Based on the original data of the patient with HFM, combined with the MIMICS software (medical image control system software), the model of the patient’s mandibular and masticatory muscles was constructed by applying the technique of three dimensional (3D) reconstruction, and then put the entity structure into the ANSYS software to simulate the effect of the surgery. Results The established preoperative and postoperative finite element analytic model could present the characteristics such as digitalization and individuation. Conclusions Compared with the effects of the real surgery for the same patient, the result of numerical simulation showed to be good matching and could provide personalized guidance for different patients before their operation.