Reconstructing three-dimensional (3D) models from two-dimensional (2D) images is necessary for preoperative planning and the customization of joint prostheses. However, the traditional statistical modeling reconstruction shows a low accuracy due to limited 3D characteristics and information loss. In this study, we proposed a new method to reconstruct the 3D models of femoral images by combining a statistical shape model with Laplacian surface deformation, which greatly improved the accuracy of the reconstruction. In this method, a Laplace operator was introduced to represent the 3D model derived from the statistical shape model. By coordinate transformations in the Laplacian system, novel skeletal features were established and the model was accurately aligned with its 2D image. Finally, 50 femoral models were utilized to verify the effectiveness of this method. The results indicated that the precision of the method was improved by 16.8%–25.9% compared with the traditional statistical shape model reconstruction. Therefore, the method we proposed allows a more accurate 3D bone reconstruction, which facilitates the development of personalized prosthesis design, precise positioning, and quick biomechanical analysis.
ObjectiveTo summarize the research progress of several three-dimensional (3-D) printing scaffold materials in bone tissue engineering. MethodThe recent domestic and international articles about 3-D printing scaffold materials were reviewed and summarized. ResultsCompared with conventional manufacturing methods, 3-D printing has distinctive advantages, such as enhancing the controllability of the structure and increasing the productivity. In addition to the traditional metal and ceramic scaffolds, 3-D printing scaffolds carrying seeding cells and tissue factors as well as scaffolds filling particular drugs for special need have been paid more and more attention. ConclusionsThe development of 3-D printing porous scaffolds have revealed new perspectives in bone repairing. But it is still at the initial stage, more basic and clinical researches are still needed.
With the developing of three-dimensional (3D) printing technology, it is widely used in the treatment of bone tumors in the clinical orthopedics. Because of the great individual differences in the location of bone tumor, resection and reconstruction are difficult. Based on 3D printing technology, the 3D models can be prepared to show the anatomical part of the disease, so that the surgeons can create a patient-specific operational plans based on better understand the local conditions. At the same time, preoperative simulation can also be carried out for complex operations and patient-specific prostheses can be further designed and prepared according to the location and size of tumor, which may have more advantages in adaptability. In this paper, the domestic and international research progress of 3D printing technology in the treatment of limb bone tumors in recent years were reviewed and summarized.
The geometric bone model of patients is an important basis for individualized biomechanical modeling and analysis, formulation of surgical planning, design of surgical guide plate, and customization of artificial joint. In this study, a rapid three-dimensional (3D) reconstruction method based on statistical shape model was proposed for femur. Combined with the patient plain X-ray film data, rapid 3D modeling of individualized patient femur geometry was realized. The average error of 3D reconstruction was 1.597–1.842 mm, and the root mean square error was 1.453–2.341 mm. The average errors of femoral head diameter, cervical shaft angle, offset distance and anteversion angle of the reconstructed model were 0.597 mm, 1.163°, 1.389 mm and 1.354°, respectively. Compared with traditional modeling methods, the new method could achieve rapid 3D reconstruction of femur more accurately in a shorter time. This paper provides a new technology for rapid 3D modeling of bone geometry, which is helpful to promote rapid biomechanical analysis for patients, and provides a new idea for the selection of orthopedic implants and the rapid research and development of customized implants.
Objective To analyze the short-term effectiveness and safety of personalized three-dimensional (3D) printed customized prostheses in severe Paprosky type Ⅲ acetabular bone defects. Methods A retrospective analysis was conducted on 8 patients with severe Paprosky type Ⅲ acetabular bone defects and met the selection criteria between January 2023 and June 2024. There were 3 males and 5 females, with an average age of 64.6 years ranged from 56 to 73 years. All primary replacement prostheses were non-cemented, including 1 ceramic-ceramic interface, 1 ceramic-polyethylene interface, and 6 metal-polyethylene interfaces. The time from the primary replacement to the revision was 4 days to 18 years. The reasons for revision were aseptic loosening in 5 cases, revision after exclusion in 2 cases, and repeated dislocation in 1 case. The preoperative Harris score was 39.5±3.7 and the visual analogue scale (VAS) score was 7.1±0.8. The operation time, intraoperative blood loss, hospital stay, and complications were recorded. The hip function was evaluated by Harris score, and the degree of pain was evaluated by VAS score. The acetabular cup abduction angle, anteversion angle, rotational center height, greater trochanter height, and femoral offset were measured on X-ray film. Results The operation time was 95-223 minutes, with an average of 151.13 minutes. The intraoperative blood loss was 600-3 500 mL, with an average of 1 250.00 mL. The hospital stay was 13-20 days, with an average of 16.88 days. All 8 patients were followed up 2-12 months, with an average of 6.4 months. One patient had poor wound healing after operation, which healed well after active symptomatic treatment. One patient had lower limb intermuscular vein thrombosis, but no thrombosis was found at last follow-up. No serious complications such as aseptic loosening, infection, dislocation, and periprosthetic fracture occurred during the follow-up. At last follow-up, the Harris score was 72.0±6.2 and the VAS score was 1.8±0.7, which were significantly different from those before operation (t=−12.011, P<0.001; t=16.595, P<0.001). On the second day after operation, the acetabular cup abduction angle ranged from 40° to 49°, with an average of 44.18°, and the acetabular cup anteversion angle ranged from 19° to 26°, with an average of 21.36°, which were within the “Lewinneck safety zone”. There was no significant difference in the rotational center height, greater trochanter height, and femoral offset between the healthy side and the affected side (P>0.05). ConclusionThe use of personalized 3D printed customized prostheses for the reconstruction of severe Paprosky type Ⅲ acetabular bone defects can alleviate pain and enhances hip joint function, and have good postoperative prosthesis position, without serious complications and have good safety.
Objective To investigate the cl inical directive significance of three-dimensional reconstruction of CT in treating mandibular angle hypertrophy. Methods Between March 2009 and January 2011, 18 patients with mandibular angle hypertrophy were treated using the three-dimensional reconstruction technology of CT. All patients were female, aged20-36 years with an average of 25 years. Eighteen patients included: 14 single mandibular angle hypertrophy, 3 mandibular angle hypertrophy with masseter hypertrophy, and 1 mandibular angle hypertrophy with bilateral asymmetry; 6 cases of ptosis of mandibular angle, 9 cases of prominent mandibular angle, and 3 cases of introversive mandibular angle. According to the types of mandibular angle hypertrophy, the surgical methods could be correctly chosen. The procedure was planned and simulated; the osteotomy l ine was marked and the osteotomy was measured on the workstations of three-dimensional reconstruction. Results No fracture of mandible occurred in the operation. Facial nerve temporary attack occurred in 1 case and recovered at 3 months after operation. All patients were followed up 6-12 months (mean, 7.6 months). After 6 months of operation, the effectiveness was satisfactory in 15 cases, basically satisfactory in 2 cases, and unsatisfactory in 1 case (bilateral asymmetry). Conclusion Based on three-dimensional reconstruction technology of CT, surgical design performed on the model will promote the accuracy of operation. Basically symmetrical appearances can be achieved with satisfactory results.
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 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.
【Abstract】ObjectiveTo evaluate the value of MR imaging with a contrast-enhanced multi-phasic isotropic volumetric interpolated breath-hold examination (VIBE) in diagnosis of primary liver carcinoma. MethodsThirty-two consecutive patients with surgical-pathologically confirmed 42 foci of primary carcinoma of liver underwent comprehensive MR examination of the upper abdomen, routine two-dimensional (2D) T1WI and T2WI images were acquired before administration of Gd-DTPA for contrast enhancement. Then, contrast-enhanced multi-phasic VIBE was acquired followed by 2D T1WI images. The lesion appearances on hepatic arterial, portal venous and equilibrium phases of VIBE sequence were carefully observed along with delineation of hepatic arterial and portal venous structures. The lesion detection rates and lesion characterization ability were compared among various MR sequences. Results33(78.6%), 30(71.4%), 38(90.5%) and 42(100%) foci were displayed respectively on T2WI, non-enhanced T1WI, enhanced T1WI and enhanced 3D-VIBE images (P＜0.05). The hepatic arterial anatomy of 30 patients （93.8%） and the portal venous structure of 31 patients （96.9%） were clearly depicted on enhanced 3D-VIBE images. Using MIP and MPR reconstruction techniques, the feeding arteries of 14 foci and draining vein of 12 foci were clearly displayed.ConclusionHigh-quality 3D-VIBE images are not only better than 2D images in lesion detection and characterization for primary liver carcinoma, but also able to provide much more information about hepatic vascular anatomy.
Objective To study the clinical significance of multi-slice spiral CT in portal vein imaging. Methods One hundred and thirty seven cases underwent enhanced scan with GE Light SpeedQX/i4 CT scanner were collected, including 41 cases of liver cancer, 20 cases of hepatic cirrhosis, 21 cases of cavernous hemangioma of liver, 9 cases of hepatic abscess, 6 cases of carcinoma of gallbladder, 14 cases of cholangiocarcinoma, 16 cases of pancreatic carcinoma, and 5 cases in normal. The results of portal vein images were reconstructed with three-dimensional software and analyzed. Results In 109 cases, portal vein, cranial mesenteric vein, and splenic vein were demonstrated successfully in the stage of portal vein: volume rendering images were clear in 84 cases, and maximum intensity projection images and multiplanar reconstruction images were clear in 109 cases. Forty-five cases of portal hypertension, 18 cases of opened collateral circulation, 15 cases of portal vein tumor thrombus, 1 case of splenic vein tumor thrombus, and 6 cases of large cavernous hemangioma were demonstrated successfully. Conclusion The portal vein imaging with multi-slice spiral CT can show the dissection and lesions of portal vein and its branches clearly, and can provide the clinical evidence for clinicians to formulate a treatment plan correctly.