Objective To study CT diagnosis of vitreous diseases in childhood.Methods 95 patients with vitreous diseases from 1999-12—2004-10 were collected.The imaging features were analysed.Results Totally there were 5 cases of persistent hyperplastic primary vitreous,9 cases of premature with retinopathy,34 cases of retinoblastoma,3 cases of Coat’s disease,23 cases of nanophthalmus,16 cases of vitreous bleeding and 5 cases of endophalmitis.Conclusion Majority of vitreous diseases can be diagnosed definitely by CT,that can guide the clinical therapy.

BACKGROUND:On CT reconstruction of three-dimensional (3D) model, fracture virtual reduction and internal fixation cannot be achieved, and reasonable operation scheme cannot be formulated. Digital design can fuly meet the needs of clinical orthopedics physicians. Standard parts database can provide the possibility to choose the ideal internal fixation. 3D printing makes the reasonable operation scheme accurate in clinical implementation. OBJECTIVE:To discuss the feasibility, accuracy and minimal invasion of internal fixation in treatment of the distal femoral fracture with digital design of standard parts database by 3D printing. METHODS: (1) Nine adult lower extremity specimens were selected to take continuously thin-layer CT scanning. After Dicom images were imported into the mimics software, the model was established. According to the AO classification, they were classified into A1-3, B1-3 and C1-3 types of distal femoral fracture by virtual design. Internal fixation with plate and screw formed standard parts database virtualy. It was printed out the pilot hole of the navigation module design by three-dimensional printing forming technique. Plate and screw were inserted assisted by the module. X-ray and CT scan were taken postoperatively to access the position. (2) 30 patients with distal femoral fracture were subjected to above fixation. The operation time, intraoperative blood loss and postoperative drainage were recorded. Imaging and curative effects were evaluated during folow-up. RESULTS AND CONCLUSION: (1) Nine samples underwent X-ray and CT scan. 3D reconstruction results revealed plate position, screw entry point, nail direction, length and diameter were consistent with presetting data in Mimics software. The navigation models were designed to fit the lateral bony structure of distal femur. There were good fitting degree, good card position and good stability when the navigation was applied. It could guide plant and screw implantation. (2) In 30 cases, the operation time was (104.63±26.12) minutes, intraoperative blood loss was (121.74±11.49) mL, and postoperative drainage volume was (30.29±6.38) mL. Al patients were folowed up. According to Schagzker criterion, the efficiency of 22 cases was excelent, 6 cases good and 2 cases average, and the excelent and good rate was 93%. The parameters of length, diameter, orientation and angle were consistent with that preoperatively. (3) Internal fixation formed by standard parts database assisted by 3D printing navigation model has advantages of high accuracy, short process, lessened blood loss, high safety, less complications, and precise fixation. Digital design of standard parts database via3D printing navigation module is expected to achieve implant navigation and application.

BACKGROUND:Preliminary experiments have performed three-dimensional (3D) reconstruction of proximal tibial fractures, digital steel plate design, the establishmentof the proximal tibia plate standard parts library and the operation simulation of 3D printing. OBJECTIVE:To explore feasibility and accuracy of standard parts library plates and screws in the proximal tibial fracture internal fixation navigation in digital design combined with 3D printing model on the basis of preliminary studies. METHODS:Dicom format images of continuous thin layer CT scanning were colected in 20 cases of proximal tibial fractures, and uploaded in Mimics software for 3D reconstruction and fracture reduction. Plate and screw selected from standard part library wereusedfor virtual fixation. Navigation module with screw channel was designed. 3D printing skeleton, bone plate, and navigation module were used for skeleton model and internal fixation. Screw and plate were placed by navigation. Navigation module card, nail and board position were observed. Postoperative appearance and CT scanning were utilized to assess outcomes. RESULTS AND CONCLUSION:After CT scanning and reconstructionin 20 skeleton models, in combination with appearance, the position of plate, screw insertion point, the direction, length and diameter of the screw were consistent with that in Mimics software. The navigation module and the corresponding proximal end of the tibia were closely bonded with good fitting degree. In the application, card slots and stability were good, and could perfectly guide plate and screw placement. These reuslts suggest that with the aid of navigation module, standard parts library plate internal fixation for proximal tibia fracture has high accuracy. On the basis of digital design and 3D printing, digital internal fixation technology of standard parts library plate is expected to achieve good implant navigation in the department of orthopedics.