Objective To establish the three-dimensional (3D) finite element model of the knee joint including posterolateral complex (PLC), and to simulate the reconstruction biomechanical analysis in this model. Methods The knee of a 26-year-old healthy man was scanned by MRI to obtain the image data of the knee in the coronal, sagittal, and axial position. First, Mimics10.01 and Hyperworks 8.0 softwares were used to extract each slice profile data of the knee joint in a two-dimensional image data respectively and to establish 3D geometric model of bone, meniscus, articular cartilage, and ligament. Second, Unigraphics software NX 4.0 was used to establish a 3D finite element model of knee joint, which had the functions of Mesh, material properties, component connection, and contact definition. Third, displacement measurement on the model and reconstructing biomechanical analysis for PLC simulation were performed. Results The 3D finite element model of the knee joint including PLC was established successfully. Under 134 N forward force, the tibia forward displacement was 4.83 mm. PLC simulation reconstruction biomechanical analysis of the 3D finite element model of the knee joint showed that under 10 N·m varus and external rotation torque conditions, the knee varus and external rotation angles of simulation reconstruction were greater than those of the intact knee, and less than those of PLC missing. Conclusion The 3D finite element model of the knee joint including PLC can be established by the reverse engineering, and it is valid and can be used as the basis for the biomechanical properties to analog reconstruction of PLC.
Objective To evaluate the directional significance of SurgiCase software in free fibula mandibular reconstruction. Methods Between September 2010 and March 2012, 10 patients with mandibular defect underwent free fibula mandibular reconstruction. There were 7 males and 3 females, with an age range of 19-43 years (mean, 27 years). The extent of lesions was 7 cm × 5 cm to 16 cm × 8 cm. In each case, three-dimensional spiral CT scan of the maxilla, mandible, and fibula was obtained before surgery. The CT data were imported into the SurgiCase software and the virtual surgery planning was performed. After that, the mandibular rapid prototyping was made according to customized design. The reconstruction surgery was then carried out using these preoperative data. During actual surgery, the extent of mandibular defect was from 6 cm × 3 cm to 16 cm × 5 cm; the length of fibula which was used to reconstruct mandible was 6-17 cm; and the area of flap was from 6 cm × 5 cm to 16 cm × 6 cm. Results Preoperative data could not be applied because the intraoperative size of tumor was larger than preoperative design in 1 case of mandibular ameloblastoma, and the fibula was shaped according to the actual osteotomy location; operations were performed successfully according to preoperative design in the other 9 patients. The operation time was 5-7 hours (mean, 6 hours). Primary healing of incision was obtained, without early complications. Ten patients were followed up 1 year. At last follow-up, 8 patients were satisfactory with the appearance and 2 patients complained with unsatisfied wide facial pattern. The panoramic radiograghs showed good bone healing. The range of mouth opening was 2.5-3.5 cm. Conclusion SurgiCase software can provide precise data for free fibula mandibular reconstruction during surgery. It can be applied widely in clinic.
Objective To study three-dimensional culturing methods of neonatal rat cardiac myocytes in simulated microgravity. Methods Neonatal rat primary cardiac myocytes were separated and seeded into polylactic acid scaffolds, stirredin spinner flasks for 24 hours, and then moved into rotary cell culture system for three-dimensional culture. The growth of cardiac myocytes was observed underinverted phase contrast microscope, scanning electron microscope and transmission electron microscope, and metabolic assay was assessed by MTT assay. Results Cardiac myocytes with sustained metabolic activity attached to the polylactic acid scaffolds, extended and confluenced. Pulsations of PLAcardiac myocytes was found in some areas. Conclusion The rotary cell culture system is suitable to develop neonatal rat cardiac myocytes culturing for three-dimensional modeling.
ObjectiveTo explore the feasibility of the repair and reconstruction of large talar lesions with three-dimensional (3D) printed talar components by biomechanical test.MethodsSix cadaveric ankle specimens were used in this study and taken CT scan and reconstruction. Then, 3D printed talar component and osteotomy guide plate were designed and made. After the specimen was fixed on an Instron mechanical testing machine, a vertical pressure of 1 500 N was applied to the ankle when it was in different positions (neutral, 10° of dorsiflexion, and 14° of plantar flexion). The pressure-bearing area and pressure were measured and calculated. Then osteotomy on specimen was performed and 3D printed talar components were implanted. And the biomechanical test was performed again to compare the changes in pressure-bearing area and pressure.ResultsBefore the talar component implantation, the pressure-bearing area of the talus varied with the ankle position in the following order: 10° of dorsiflexion > neutral position > 14° of plantar flexion, showing significant differences between positions ( P<0.05). The pressure exerted on the talus varied in the following order: 10° of dorsiflexion < neutral position < 14° of plantar flexion, showing significant differences between positions (P<0.05). The pressure-bearing area and pressure were not significantly different between before and after talar component implantations in the same position (P>0.05). The pressure on the 3D printed talar component was not significantly different from the overall pressure on the talus (P>0.05).ConclusionApplication of the 3D printed talar component can achieve precise repair and reconstruction of the large talar lesion. The pressure on the repaired site don’t change after operation, indicating the clinical feasibility of this approach.
Objective To explore the histochemical staining for distinguishing and local izing nerve fibers and fascicles at histological level in three-dimensional reconstruction of peri pheral nerves. Methods The right median nerve was harvested from one fresh cadaver and embedded in OCT compound. The sample was serially horizontally sl iced with 6 μm thickness. All sections were stained with Karnovsky-Roots method (group A, n=30) firstly and then stained with toluidine blue (group B, =28) and Ponceau 2R (group C, n=21) in proper sequence. The results of each step were taken photos (× 100). After successfully stitching, the two-dimensional panorama images were compared, including texture feature, the number and aver gray level of area showing acetylchol inesterase (AchE) activity, and result of auto microscopic medical image segmentation. Results In groups A, B, and C, the number of AchE-positive area was (21.63 ± 4.06)× 102, (20.64 ± 3.51)× 102, and (20.54 ± 5.71)× 102, respectively, showing no significant difference among 3 groups (F=0.64, P=0.54); the mean gray level was (1.41 ± 0.06)× 102, (1.10 ± 0.05)× 102, and (1.14 ± 0.07)× 102, respectively, showing significant differences between group A and groups B and C (P lt; 0.001). In the image of group A, only AchE-positive area was stained; in the image of group B, myelin sheath was obscure; and in the image of group C, axons and myelin sheath could be indentified, the character of nerve fibers could be distinguished clearly and accurately, and the image segmentation of fascicles could be achieved easier than other 2 images. Conclusion The image of Karnovsky-Roots-toluidine blue-Ponceau 2R staining has no effect on the AchE-positive area in the image of Karnovsky-Roots staining and shows better texture feature. This improved histochemical process may provide ideal image for the three-dimensional reconstruction of peri pheral nerves.
Objective To study the feasibility of virtual intercondylar notchplasty by applying MRI two-dimensional (2D) images to reconstruct three-dimensional (3D) images and measure the size of intercondylar notch. Methods Thirty healthy volunteers who had no knee joint disease and surgery history were selected. There were 15 females and 15 males with an age range of 20-30 years, weight range of 45-74 kg, and height range of 150-185 cm. They were divided into male group and female group, and the knees of each group were divided into 2 subgroups (the left group and right group). MRI scan of the left and right knees was performed, and the 2D images of MRI were imported into Mimics10.01 medical image control system for 3D reconstruction. The related anatomical data as follows were measured from the 3D digital model and analyzed by statistical software: notch width (NW), condylar width (CW), and notch width index (NWI). Then the 3D knee images of patients with anterior cruciate ligament (ACL) injury were collected between January and March 2010, and 4 patients with narrow intercondylar notch (NWI≤0.2) were selected for reconstructing the 3D model of the knee and simulating the intercondylar notch plasty. Then, the volume of osteotomy in 3D model was calculated and applied in the ACL reconstruction surgery, and whether the graft had impingement with intercondylar notch or not was evaluated. Results There were significant differences in NW and CW between male group and female group (P≤lt;≤0.05), but no significant difference was found in the NWI (P≤gt;≤0.05). And there was no significant difference in NW, CW, and NWI between the left and right knees both in male group and female group (P≤gt;≤0.05). After ACL reconstruction and intercondylar notchplasty, the shape of intercondylar notch became normal (NWI≤gt;≤0.22), no impingement occurred between the graft and intercondylar notch under arthroscopy within 3-month follow-up. Conclusion The shape of intercondylar notch of 3D model based on MRI 2D images is similar to the real intercondylar notch. NWI is one of important indexes which can reflect the narrow level of intercondylar notch. The virtual intercondylar notchplasty may provide preoperative plan and guidence for ACL reconstruction operation to avoid the impingement between graft and intercondylar notch after surgery.
Objective To investigate and analyze the three-dimensional anatomic structure of glenoid bone in some Chinese people so as to provide the accurate anatomic data to design the new prosthesis of glenoid bone for Chinese people. Methods A total of 90 volunteers with two healthy shoulders (52 males and 38 females, aging 19-60 years with an average of 39.6 years) were selected. Five parameters were measured by use of three-dimensional computed tomography, volumerendering technique (VRT) and multiplanar reformation (MPR), including the maximum antero-posterior width (MAPW),antero-posterior radius of curvature (APROC), maximum supero-inferior height (MSIH), supero-inferior radius of curvature(SIROC) and version angle (VA) of glenoid. All parameters were measured two times, and the average values were analysed by SPSS13.0. The level of significance was set at P lt; 0.05. Results The average MAPW was (2.51 ± 0.32) cm, the average APROC was (5.50 ± 1.21) cm, the average MSIH was (3.45 ± 0.29) cm, the average SIROC was (3.98 ± 0.55) cm, and the average VA was (— 0.03 ± 4.66)°. There were no significant differences (P gt; 0.05) in MAPW, APROC, MSIH, SIROC and VA between two sides. There were significant differences (P lt; 0.05) in MAPW, MSIH, SIROC and VA, and no significant difference (P gt; 0.05) in APROC between female and male. MAPW was correlated with APROC, MAPW was correlated with MSIH, APROC was correlated with SIROC, and the correlation coefficient was 0.298, 0.495 and 0.262, respectively. Conclusion There are no significant differences in MAPW, APROC, MSIH, SIROC and VA of glenoid between two sides. There are sexual significant differences in MAPW, MSIH, SIROC and VA. The data and its statistical results may serve as guidel ines for the design of the glenoid component.
The interventional therapy of vascular stent implantation is a popular treatment method for cardiovascular stenosis and blockage. However, traditional stent manufacturing methods such as laser cutting are complex and cannot easily manufacture complex structures such as bifurcated stents, while three-dimensional (3D) printing technology provides a new method for manufacturing stents with complex structure and personalized designs. In this paper, a cardiovascular stent was designed, and printed using selective laser melting technology and 316L stainless steel powder of 0?10 μm size. Electrolytic polishing was performed to improve the surface quality of the printed vascular stent, and the expansion behavior of the polished stent was assessed by balloon inflation. The results showed that the newly designed cardiovascular stent could be manufactured by 3D printing technology. Electrolytic polishing removed the attached powder and reduced the surface roughness Ra from 1.36 μm to 0.82 μm. The axial shortening rate of the polished bracket was 4.23% when the outside diameter was expanded from 2.42 mm to 3.63 mm under the pressure of the balloon, and the radial rebound rate was 2.48% after unloading. The radial force of polished stent was 8.32 N. The 3D printed vascular stent can remove the surface powder through electrolytic polishing to improve the surface quality, and show good dilatation performance and radial support performance, which provides a reference for the practical application of 3D printed vascular stent.
ObjectiveTo explore the value and role of post-processing techniques such as 3D reconstruction in the online education mode in neurosurgery undergraduate clinical probation teaching.MethodsA retrospective analysis method was used to collect 120 clinical 5-year medical students who were trained in neurosurgery at West China Hospital of Sichuan University from January 2019 to May 2020, including 40 students receiving traditional imaging materials offline (control group 1), 40 students being taught on image post-processing technology offline (control group 2), and 40 students being taught on-line image post-processing technology during the novel coronavirus epidemic (observational group). The students’ scores of departmental rotation examination and feedback survey results on teaching satisfaction were collected, and multiple comparison was conducted between the observational group and the two control groups respectively.ResultIn the control group 1, the control group 2, and the observational group, the theoretical test scores were 36.80±3.22, 38.17±2.61, and 38.97±2.79, respectively; the case analysis scores were 37.05±2.01, 38.40±2.62, and 39.25±2.88, respectively; the total scores were 73.85±5.06, 76.57±4.29, and 78.10±4.53, respectively; the scores of interest in teaching were 84.47±3.71, 86.05±2.87, and 86.82±2.60, respectively; the scores of mastery of knowledge were 82.85±4.39, 84.90±2.72, and 85.78±2.36, respectively; and the scores of overall satisfaction with teaching were 84.17±3.45, 85.97±2.64, and 86.37±2.59, respectively. The differences among the three groups were all statistically significant (P<0.05). The observational group differed significantly from the control group 1 in all the above scores (P<0.05), while did not differed from the control group 2 in any of the above scores (P>0.05).ConclusionsIn neurosurgery internship activities, the online application of image post-processing techniques such as 3D reconstruction will help students establish 3D spatial concepts, better understand the brain anatomy, and improve students’ academic performance and acceptance.
Objective To discuss the effect of the calcaneocuboid arthrodesis on three-dimensional kinematics of talonavicular joint and its clinical significance. Methods Ten freshfrozen foot specimens, three-dimensional kinematics oftalonavicular joint were determined in the case of neutral position, dorsiflexion, plantoflexion, adduction, abduction, inversion and eversion motion by meansof threedimensional coordinate instrument（Immersion MicroScribe G2X） before and after calcaneocuboid arthrodesis under non-weight with moment of couple, bending moment, equilibrium dynamic loading. Calcaneocuboid arthrodesis was performed on these feet in neutral position and the lateral column of normal length. Results A significant decrease in the three-dimensional kinematics of talonavicular joint was observed（P＜0.01）in cadaver model following calcaneocuboid arthrodesis. Talonavicular joint motion was diminished by 31.21%±6.08％ in sagittal plane; by 51.46%±7.91％ in coronal plane; by 36.98%±4.12％ in transverse plane; and averagely by 41.25%±6.02％. Conclusion Calcaneocuboid arthrodesis could limite motion of the talonavicular joints, and the disadvantage of calcaneocuboid arthrodesis shouldn’t be neglected.