Objective To evaluate the feasibility and short-term effectiveness of three-dimensional (3D) printed titanium-alloy prosthesis reconstruction after the distal tibia tumor segment resection. Methods The clinical data of 6 patients with bone defect after distal tibia tumor segment resection treated with 3D printed titanium-alloy prosthesis reconstruction and tibiotalar joint fusion between January 2020 and December 2021 were retrospectively analyzed. There were 2 males and 4 females; the age ranged from 12 to 35 years, with an average of 18.5 years. Among them, 4 cases were osteosarcoma, 1 case was Ewing sarcoma, and 1 case was giant cell tumor of bone. The Enneking staging was stage ⅡA in 3 cases, stage ⅡB in 2 cases, and stage Ⅲ in 1 case. The disease duration was 2-5 months (mean, 3.2 months). All patients received preoperative neoadjuvant therapy, and patients with osteosarcoma and Ewing sarcoma started chemotherapy at3 weeks after operation. The systemic and local tumor conditions and prosthesis conditions were evaluated regularly after operation. The Musculoskeletal Tumor Society (MSTS) score and the American Orthopaedic Foot and Ankle Society (AOFAS) score were used to evaluate the lower extremity and ankle function. Results All patients were followed up 8-26 months, with an average of 15.6 months. There was no local recurrence and distant metastasis during the follow-up. The ankle joints of 5 cases were all in 90° functional position at last follow-up, and there was no complication such as prosthesis loosening and fracture; the ankle joint fusion was stable, the local bone ingrowth was good, and the daily activities could be completed, but the ankle range of motion was limited and the ankle joint was stiff. The MSTS score ranged from 22 to 26, with an average of 24, and 3 cases were evaluated as excellent and 2 cases were good; the AOFAS score ranged from 71 to 86, with an average of 80.6, and 4 cases were evaluated as good and 1 case was fair. One patient had severe periprosthetic infection at 2 months after operation, resulting in failure of prosthesis implantation, pain in limb movement, and poor ankle function; MSTS score was 12, AOFAS score was 50, and both were evaluated as poor; distraction osteogenesis was performed after removal of prosthesis and infection control, at present, it was still in the process of distraction osteogenesis, and local osteogenesis was acceptable. Conclusion Using 3D printed titanium-alloy prosthesis and tibiotalar joint fusion to reconstruct the bone defect after distal tibia tumor segment resection has satisfactory mechanical stability and function, and is one of the effective distal tibial limb salvage methods.
ObjectiveTo evaluate myocardial segmental motion function in left ventricular of patients with rheumatic mitral stenosis by using the technology of real-time three-dimensional echocardiography (RT-3DE). MethodsWe retrospectively analyzed the clinical data of 14 patients with rheumatic mitral stenosis between October and November 2014 in our hospital as a trial group. There were 4 males and 10 females with a mean age of 50.9±9.0 years ranging from 34 to 64 years. We chose 11 healthy individuals as a control group. There were 7 males and 4 females with a mean age of 49.5±9.7 years ranging from 32 to 67 years. Both the two groups were subjected to myocardial performance evaluation using two-dimensional echocardiography (2DE) and real-time three-dimensional echocardiography (RT-3DE) to examine the left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), longitudinal strain, circumferential strain, area strain, and lateral strain of each left ventricular myocardial segments. Result RT-3DE detected that the trial group had significantly lower values of LVEF, LVEDV and LVESV than those of the control group (P < 0.05). RT-3DE also revealed that the trial group had a significantly weaker longitudinal strain than the control group (P < 0.05). ConclusionRT-3DE is an accurate technology for assessing myocardial motion and function in patients with rheumatic mitral valve disease.
Objective To investigate the feasibility and application value of digital technology in establishing the micro-vessels model of cross-boundary perforator flap in rat. Methods Twenty 8-week-old female Sprague Dawley rats, weighing 280-300 g, were used to established micro-vessels model. The cross-boundary perforator flaps of 10 cm×3 cm in size were prepared at the dorsum of 20 rats; then the flaps were suturedin situ. Ten rats were randomly picked up at 3 and 7 days after operation in order to observe the necrosis of flap and measure the percentage of flap necrosis area; the lead-oxide gelatin solution was used for vessels perfusion; flaps were harvested and three-dimensional reconstruction of micro-vessel was performed after micro-CT scanning. Vascular volume and total length were measured via Matlable 7.0 software. Results The percentage of flap necrosis area at 3 days after operation was 19.08%±3.64%, which was significantly lower than that at 7 days (39.76%±3.76%;t=10.361, P=0.029). Three-dimensional reconstruction via the micro-CT clearly showed the morphological alteration of micro-vessel of the flap. At 3 days after operation, the vascular volume of the flap was (1 240.23±89.71) mm3 and the total length was (245.94±29.38) mm. At 7 days after operation, the vascular volume of the flap was (1 036.96±88.97) mm3 and the total length was (143.20±30.28) mm. There were significant differences in the vascular volume and the total length between different time points (t=5.088, P=0.000; t=7.701, P=0.000). Conclusion The digital technology can be applied to visually observe and objectively evaluate the morphological alteration of the micro-vessels of the flap, and provide technical support for the study of vascular model of flap.
A three-dimensional finite element model of premaxillary bone and anterior teeth was established with ANSYS 13.0. The anterior teeth were fixed with strong stainless labial archwire and lingual frame. In the horizontal loading experiments, a horizontal retraction force of 1.5 N was applied bilaterally to the segment through hooks at the same height between 7 and 21 mm from the incisal edge of central incisor; in vertical loading experiments, a vertical intrusion force of 1.5 N was applied at the midline of lingual frame with distance between 4 and 16 mm from the incisal edge of central incisor. After loading, solution was done and displacement and maximum principle stress were calculated. After horizontal loading, lingual displacement and stress in periodontal membrane (PDM) was most homogeneous when the traction force was 14 mm from the edge of central incisor; after vertical loading, intrusive displacement and stress in PDM were most homogeneous when the traction force was 12 mm from the incisal edge of central incisor. The results of this study suggested that the location of center of resistance (CRe) of six maxillary anterior teeth is about 14 mm gingivally and 12 mm lingually to incisal edge of central incisor. The location can provide evidence for theoretical and clinical study in orthodontics.
Objective To evaluated the application effect of reverse digital modeling combined with three-dimensional (3D)-printed disease models in the standardized training of orthopedic residents focusing on pelvic tumors. Methods From August 2022 to August 2023, 60 orthopedic residents from West China Hospital, Sichuan University were randomly assigned to a trial group (n=30) and a control group (n=30). The trial group received instruction using reverse digital modeling and 3D-printed pelvic tumor models, while the control group underwent traditional teaching methods. Teaching outcomes were evaluated and compared between groups through knowledge tests, practical skill assessments, and satisfaction surveys. Results Before training, there was no statistically significant difference in knowledge tests or practical skill assessments between the two groups (P>0.05). After training, the trial group showed significantly better performance than the control group in knowledge tests (90.5±5.2 vs. 78.4±6.8, P<0.05), skill assessments (92.7±4.9 vs. 81.3±6.2, P<0.05), and satisfaction surveys (9.40±1.10 vs. 7.60±1.20, P<0.05). One month after training, the trial group still showed significantly better performance than the control group in knowledge tests (88.1±6.4 vs. 72.3±7.1, P<0.05) and skill assessments (90.3±5.8 vs. 75.6±6.9, P<0.05). Conclusions Reverse digital modeling combined with 3D printing offers an intuitive and effective teaching approach that improves comprehension of pelvic tumor anatomy and strengthens clinical and technical competencies. This method significantly enhances learning outcomes in standardized residency training and holds promise for broader integration into medical education.
In this paper, a new method for the classification of Alzheimer’s disease (AD) using multi-feature combination of structural magnetic resonance imaging is proposed. Firstly, hippocampal segmentation and cortical thickness and volume measurement were performed using FreeSurfer software. Then, histogram, gradient, length of gray level co-occurrence matrix and run-length matrix were used to extract the three-dimensional (3D) texture features of the hippocampus, and the parameters with significant differences between AD, MCI and NC groups were selected for correlation study with MMSE score. Finally, AD, MCI and NC are classified and identified by the extreme learning machine. The results show that texture features can provide better classification results than volume features on both left and right sides. The feature parameters with complementary texture, volume and cortical thickness had higher classification recognition rate, and the classification accuracy of the right side (100%) was higher than that of the left side (91.667%). The results showed that 3D texture analysis could reflect the pathological changes of hippocampal structures of AD and MCI patients, and combined with multi-feature analysis, it could better reflect the essential differences between AD and MCI cognitive impairment, which was more conducive to clinical differential diagnosis.
Objective To realize the visualization of three-dimensional microstructure of rabbit sciatic nerve bundles by micro-CT and three-dimensional visualization software Mimics17.0. Methods The sciatic nerve tissues from 6 New Zealand rabbits were divided into 2 groups (n=3), and the sciatic nerve tissues were stained by 1% (group A) and 5% (group B) Lugol solution respectively. After staining for 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 hours, the imaging changes of specimens were observed by light microscope and micro-CT. The clear micro-CT images were exported to the Mimics software to complete the visualization of three-dimensional microstructure of rabbit sciatic nerve according to three-dimensional reconstruction tool. Results The clear three-dimensional microstructure images could be observed in group A at 2.5 hours after staining and in group B at 1.5 hours after staining by light microscope and micro-CT. The sciatic nerve of New Zealand rabbits were divides into 3 bundles and each of them was relatively fixed. There was no obvious crossing or mergers between each bundle. The cross-sectional area of each bundle was (0.425±0.013), (0.038±0.007), and (0.242±0.026) mm2 respectively. The digital model could clearly reflect the microstructure of the sciatic nerve at all cross sections. Conclusion The internal structure of New Zealand rabbits sciatic nerve can be clearly reflected by micro-CT scanning. It provides a reliable method for establishing a nerve microstructure database with large amount specimens.
Objective To analyze the characteristics of femoral neck fractures in young and middle-aged adults by means of medical image analysis and fracture mapping technology to provide reference for fracture treatment. Methods A clinical data of 159 young and middle-aged patients with femoral neck fractures who were admitted between December 2018 and July 2019 was analyzed. Among them, 99 patients were male and 60 were female. The age ranged from 18 to 60 years, with an average age of 47.9 years. There were 77 cases of left femoral neck fractures and 82 cases of right sides. Based on preoperative X-ray film and CT, the fracture morphology was observed and classified according to the Garden classification standard and Pauwels’ angle, respectively. Mimics19.0 software was used to reconstruct the three-dimensional models of femoral neck fracture, measure the angle between the fracture plane and the sagittal plane of the human body, and observe whether there was any defect at the fracture end and its position on the fracture surface. Through reconstruction, virtual reduction, and image overlay, the fracture map was established to observe the fracture line and distribution. Results According to Garden classification standard, there were 6 cases of type Ⅰ, 61 cases of type Ⅱ, 54 cases of type Ⅲ, and 38 cases of type Ⅳ. According to the Pauwels’ angle, there were 12 cases of abduction type, 78 cases of intermediate type, and 69 cases of adduction type. The angle between fracture plane and sagittal plane of the human body ranged from –39° to +30°. Most of them were Garden type Ⅱ, Ⅳ and Pauwels intermediate type. The fracture blocks were mainly in the form of a triangle with a long base and mainly distributed below the femoral head and neck junction area. Twenty-six cases (16.35%) were complicated with bone defects, which were mostly found in Garden type Ⅲ, Ⅳ, and Pauwels intermediate type, located at the back of femoral neck and mostly involved 2-4 quadrants. The fracture map showed that the fracture line of the femoral neck was distributed annularly along the femoral head and neck junction. The fracture line was dense above the femoral neck and scattered below, involving the femoral calcar. Conclusion The proportion of displaced fractures (Garden type Ⅲ, Ⅳ) and unstable fractures (Pauwels intermediate type, adduction type) is high in femoral neck fractures in young and middle-aged adults, and comminuted fractures and bone defects further increase the difficulty of treatment. In clinical practice, it is necessary to choose treatment plan according to fracture characteristics. Anatomic reduction and effective fixation are the primary principles for the treatment of femoral neck fracture in young and middle-aged adults.
Spinal fusion is a standard operation for treating moderate and severe intervertebral disc diseases. In recent years, the proportion of three-dimensional printing interbody fusion cage in spinal fusion surgery has gradually increased. In this paper, the research progress of molding technology and materials used in three-dimensional printing interbody fusion cage at present is summarized. Then, according to structure layout, three-dimensional printing interbody fusion cages are classified into five types: solid-porous-solid (SPS) type, solid-porous-frame (SPF) type, frame-porous-frame (FPF) type, whole porous cage (WPC) type and others. The optimization process of three-dimensional printing interbody fusion cage and the advantages and disadvantages of each type are analyzed and summarized in depth. The clinical application of various types of 3D printed interbody fusion cage was introduced and summarized later. Lastly, combined with the latest research progress and achievements, the future research direction of three-dimensional printing interbody fusion cage in molding technology, application materials and coating materials is prospected in order to provide some reference for scholars engaged in interbody fusion cage research and application.
ObjectiveTo review the current research and application progress of three-dimentional (3D) printed porous titanium alloy after tumor resection, and provide direction and reference for the follow-up clinical application and basic research of 3D printed porous titanium alloy. MethodsThe related literature on research and application of 3D printed porous titanium alloy after tumor resection in recent years was reviewed from three aspects: performance of simple 3D printed porous titanium alloy, application analysis of simple 3D printed porous titanium alloy after tumor resection, and research progress of anti-tumor 3D printed porous titanium alloy. Results3D printing technology can adjust the pore parameters of porous titanium alloy, so that it has the same biomechanical properties as bone. Appropriate pore parameters are conducive to inducing bone growth, promoting the recovery of skeletal system and related functions, and improving the quality of life of patients after operation. Simple 3D printed porous titanium alloy can more accurately match the bone defect after tumor resection through preoperative personalized design, so that it can closely fit the surgical margin after tumor resection, and improve the accuracy and efficiency of the operation. The early and mid-term follow-up results show that its application reduces the postoperative complications such as implant loosening, subsidence, fracture and so on, and enhances the bone stability. The anti-tumor performance of 3D printed porous titanium alloy mainly includes coating and drug-loading treatment of pure 3D printed porous titanium alloy, and some progress has been made in the basic research stage. ConclusionSimple 3D printed porous titanium alloy is suitable for patients with large and complex bone defects after tumor resection, and the anti-tumor effect of 3D printed porous titanium alloy can be achieved through coating and drug delivery.