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.
Objective To review the application progress of digital technology in auricle reconstruction. Methods The recently published literature concerning the application of digital technology in auricle reconstruction was extensively consulted, the main technology and its specific application areas were reviewed. Results Application of digital technology represented by three-dimensional (3D) data acquisition, 3D reconstruction, and 3D printing is an important developing trend of auricle reconstruction. It can precisely guide auricle reconstruction through fabricating digital ear model, auricular guide plate, and costal cartilage imaging. Conclusion Digital technology can improve effectiveness and decrease surgical trauma in auricle reconstruction. 3D bioprinting of ear cartilage future has bright prospect and needs to be further researched.
ObjectiveTo explore a method of three-dimensional (3D) printing technology for preparation of personalized rat brain tissue cavity scaffolds so as to lay the foundation for the repair of traumatic brain injury (TBI) with tissue engineered customized cavity scaffolds. MethodsFive male Sprague Dawley rats[weighing (300±10) g] were induced to TBI models by electric controlled cortical impactor. Mimics software was used to reconstruct the surface profile of the damaged cavity based on the MRI data, computer aided design to construct the internal structure. Then collagen-chitosan composite was prepared for 3D bioprinter of bionic brain cavity scaffold. ResultsMRI scans showed the changes of brain tissue injury in the injured side, and the position of the cavity was limited to the right side of the rat brain cortex. The 3D model of personalized cavity containing the internal structure was successfully constructed, and cavity scaffolds were prepared by 3D printing technology. The external contour of cavity scaffolds was similar to that of the injured zone in the rat TBI; the inner positive crossing structure arranged in order, and the pore connectivity was good. ConclusionCombined with 3D reconstruction based on MRI data, the appearance of cavity scaffolds by 3D printing technology is similar to that of injured cavity of rat brain tissue, and internal positive cross structure can simulate the topological structure of the extracellular matrix, and printing materials are collagen-chitosan complexes having good biocompatibility, so it will provide a new method for customized cavity scaffolds to repair brain tissue cavity after TBI.
ObjectiveTo investigate the effectiveness of digital three-dimensional (3D) printing osteotomy guide plate assisted total knee arthroplasty (TKA) in treatment of knee osteoarthritis (KOA) patients with femoral internal implants. Methods The clinical data of 55 KOA patients who met the selection criteria between July 2021 and October 2023 were retrospectively analyzed. Among them, 26 cases combined with femoral implants were treated with digital 3D printing osteotomy guide plate assisted TKA (guide plate group), and 29 cases were treated with conventional TKA (control group). There was no significant difference in gender, age, body mass index, side, Kellgren-Lawrence classification, preoperative visual analogue scale (VAS) score, Hospital for Special Surgery (HSS) knee score, knee range of motion, and other baseline data between the two groups (P>0.05). The operation time, intraoperative blood loss, incision length, postoperative first ambulation time, surgical complications; VAS score, knee HSS score, knee range of motion before operation, at 1 week and 3 months after operation, and at last follow-up; distal femoral lateral angle, proximal tibial medial angle, hip-knee-ankle angle and other imaging indicators at last follow-up were recorded and compared between the two groups. ResultsThe operation time, incision length, intraoperative blood loss, and postoperative first ambulation time in the guide plate group were significantly lower than those in the control group (P<0.05). In the control group, there were 1 case of incision rupture and bleeding and 1 case of lower limb intermuscular venous thrombosis, which was cured after symptomatic treatment. There was no complication such as neurovascular injury, incision infection, or knee prosthesis loosening in both groups. Patients in both groups were followed up 12-26 months, with an average of 16.25 months. The VAS score, HSS score, and knee range of motion improved at each time point after operation in both groups, and further improved with time after operation, the differences were significant (P<0.05). The above indicators in the guide plate group were significantly better than those in the control group at 1 week and 3 months after operation (P<0.05), and there was no significant difference between the two groups at last follow-up (P>0.05). At last follow-up, the distal femoral lateral angle, the proximal tibial medial angle, and the hip-knee-ankle angle in the guide plate group were significantly better than those in the control group (P<0.05). Conclusion The application of digital 3D printing osteotomy guide plate assisted TKA in the treatment of KOA patients with femoral implants can simplify the surgical procedures, overcome limitations of conventional osteotomy guides, reduce surgical trauma, achieve individualized and precise osteotomy, and effectively restore lower limb alignment and knee joint function.
Objective To discuss the effect of three-dimensional (3D) printing individualized model and guide plate in bone tumor surgery. Methods Between October 2015 and December 2016, 3D printing individualized model and guide plate for making preoperative surgical planning and intraoperative treatment were used in 5 patients of bone tumor. All the patients were male, with a median age of 32 years (range, 9-58 years). There were 1 case of cystic echinococcosis at left pelvis and pathological fracture of the proximal femur; 1 case of left iliac bone osteoblastoma associated with aneurysmal bone cyst; 1 case of fibrous dysplasia of the left femur (sheep horn deformity) with pathological fracture; 1 case of metastatic carcinoma of right calcaneus (tumor staging was T2N0M0); and 1 case of Ewing sarcoma of left femur (tumor staging was T2N0M0). The disease duration ranged from 1 month to 10 years (mean, 2.25 years). Results The operation was completed successfully. The operation time was 2.6-7.5 hours (mean, 4.9 hours). The intraoperative blood loss was 200-2 500 mL (mean, 1 380 mL). The intraoperative fluoroscopy times was 1-6 times (mean, 3.8 times). There was no infection after operation, and the blood supply and nerve function were good. All the patients were followed up 3-16 months (mean, 5.4 months). No loosening or breaking of the internal fixator occurred. According to Enneking scoring system, the limb function score was 15-26 (mean, 21); and the results were excellent in 2 cases, good in 2 cases, and fair in 1 case. Conclusion 3D printing technology can make the implementation of the better preoperative planning and evaluation in bone tumor surgery, and it provides a new reference for individualized treatment in patients with bone tumor.
ObjectiveTo review the current progress of three-dimensional (3-D) printing technique in the clinical practice, its limitations and prospects. MethodsThe recent publications associated with the clinical application of 3-D printing technique in the field of surgery, especially in orthopaedics were extensively reviewed. ResultsCurrently, 3-D printing technique has been applied in orthopaedic surgery to aid diagnosis, make operative plans, and produce personalized prosthesis or implants. Conclusion3-D printing technique is a promising technique in clinical application.
Objective To review the current research progress of three-dimensional (3-D) printing technique in foot and ankle surgery. Methods Recent literature associated with the clinical application of 3-D printing technique in the field of medicine, especially in foot and ankle surgery was reviewed, summarized, and analyzed. Results At present, 3-D printing technique has been applied in foot and ankle fracture, segmental bone defect, orthosis, corrective surgery, reparative and reconstructive surgery which showed satisfactory effectiveness. Currently, there are no randomized controlled trials and the medium to long term follow-up is necessary. Conclusion The printing materials, time, cost, medical ethics, and multi-disciplinary team restricted the application of 3-D printing technique, but it is still a promising technique in foot and ankle surgery.
Objective To evaluate the effectiveness of three-dimensional (3-D) printing assisting minimally invasive for intraarticular calcaneal fractures with percutaneous poking reduction and cannulate screw fixation. Methods A retrospective analysis was performed of the 19 patients (19 feet) with intraarticular calcaneal fracture who had been treated between March 2015 and May 2016. There were 13 males and 6 females with an average age of 38.2 years (range, 24-73 years). There were 3 open fractures and 16 closed fractures. By Sanders classification, 12 cases were type Ⅱ, 7 cases were type Ⅲ. By Essex-Lopresti classification, 13 cases were tongue type, 6 cases were joint-depression type. The time from injury to surgery was 1-10 days (mean, 4.7 days). A thin slice CT scan was taken of bilateral calcaneus in patients. By using the mirror imaging technique, the contralateral mirror image and the affected side calcaneus model were printed according to 1∶1 ratio. The displacement of fracture block was observed and contrasted, and the poking reduction was simulated. Calcaneal fracture was treated by percutaneous minimally invasive poking reduction and cannulate screw fixation. The Böhler angle and Gissane angle at immediate after operation and last follow-up was measured on X-ray films, and compared with preoperative measurement. The functional recovery was evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) scores. Results The operation time was 25-70 minutes (mean, 45 minutes). The intraoperative blood loss was 10-40 mL (mean, 14.5 mL). All the incisions healed by first intention and had no relevant postoperative complications such as skin necrosis, nail tract infection, and osteomyelitis. All the patients were followed up 12-25 months (mean, 14.6 months). All patients obtained fracture healing, and the fracture healing time was 8-14 weeks (mean, 10.3 weeks). No screw withdrawal or breakage occurred during follow-up; only 1 patient with Sanders type Ⅱ fracture, whose calcaneus height was partially lost at 6 weeks after operation, the other patients had no reduction loss and fracture displacement, and no traumatic arthritis occurred. The Böhler angle and Gissane angle at immediate after operation and last follow-up were significantly improved when compared with preoperative ones (P<0.05), but there was no significant difference between at immediate after operation and last follow-up (P>0.05). The AOFAS score was 76-100 (mean, 88.2), and the results were excellent in 10 feet, good in 7, and fair in 2, the excellent and good rate was 89.5%. Conclusion 3-D printing assisting minimally invasive for intraarticular calcaneal fractures with percutaneous poking reduction and cannulate screw fixation can reduce the surgical trauma, improve the quality of reduction and fixation, and make the operation more safe, accurate, and individualized.
ObjectiveTo solve the fixation problem between ligament grafts and host bones in ligament reconstruction surgery by using ligament-bone composite scaffolds to repair the ligaments, to explore the fabrication method for ligament-bone composite scaffolds based on three-dimensional (3-D) printing technique, and to investigate their mechanical and biological properties in animal experiments. MethodsThe model of bone scaffolds was designed using CAD software, and the corresponding negative mould was created by boolean operation. 3-D printing techinique was employed to fabricate resin mold. Ceramic bone scaffolds were obtained by casting the ceramic slurry in the resin mould and sintering the dried ceramics-resin composites. Ligament scaffolds were obtained by weaving degummed silk fibers, and then assembled with bone scaffolds and bone anchors. The resultant ligament-bone composite scaffolds were implanted into 10 porcine left anterior cruciate ligament rupture models at the age of 4 months. Mechanical testing and histological examination were performed at 3 months postoperatively, and natural anterior cruciate ligaments of the right sides served as control. ResultsBiomechanical testing showed that the natural anterior cruciate ligament of control group can withstand maximum tensile force of (1 384±181) N and dynamic creep of (0.74±0.21) mm, while the regenerated ligament-bone scaffolds of experimental group can withstand maximum tensile force of (370±103) N and dynamic creep of (1.48±0.49) mm, showing significant differences (t=11.617,P=0.000; t=-2.991,P=0.020). In experimental group, histological examination showed that new bone formed in bone scaffolds. A hierarchical transition structure regenerated between ligament-bone scaffolds and the host bones, which was similar to the structural organizations of natural ligament-bone interface. ConclusionLigament-bone composite scaffolds based on 3-D printing technique facilitates the regeneration of biomimetic ligament-bone interface. It is expected to achieve physical fixation between ligament grafts and host bone.
ObjectiveTo investigate the effects of three-dimensional (3D) printed Ti6Al4V-4Cu alloy on inflammation and osteogenic gene expression in mouse bone marrow mesenchymal stem cells (BMSCs) and mouse mononuclear macrophage line RAW264.7.MethodsTi6Al4V and Ti6Al4V-4Cu alloys were prepared by selective laser melting, and the extracts of the two materials were prepared according to the biological evaluation standard of medical devices. The effects of two kinds of extracts on the proliferation of mouse BMSCs and mouse RAW264.7 cells were detected by cell counting kit 8 method. After co-cultured with mouse BMSCs for 3 days, the expression of osteogenesis- related genes [collagen type Ⅰ (Col-Ⅰ), alkaline phosphatase (ALP), Runx family transcription factor 2 (Runx-2), osteoprotegerin (OPG), and osteopontin (OPN)] were detected by real-time fluorescence quantitative PCR. After co-cultured with mouse RAW264.7 cells for 1 day, the expressions of inflammation-related genes [interleukin 4 (IL-4) and nitric oxide synthase 2 (iNOS)] were detected by real-time fluorescence quantitative PCR, and the supernatants of the two groups were collected to detect the secretion of vascular endothelial growth factor a (VEGF-a) and bone morphogenetic protein 2 (BMP-2) by ELISA. The osteogenic conditioned medium were prepared with the supernatants of the two groups and co-cultured with BMSCs for 3 days. The expressions of osteogenesis-related genes (Col-Ⅰ, ALP, Runx-2, OPG, and OPN) were detected by real-time fluorescence quantitative PCR.ResultsCompared with Ti6Al4V alloy extract, Ti6Al4V-4Cu alloy extract had no obvious effect on the proliferation of BMSCs and RAW264.7 cells, but it could promote the expression of OPG mRNA in BMSCs, reduce the expression of iNOS mRNA in RAW264.7 cells, and promote the expression of IL-4 mRNA. It could also promote the secretions of VEGF-a and BMP-2 in RAW264.7 cells. Ti6Al4V-4Cu osteogenic conditioned medium could promote the expressions of Col-Ⅰ, ALP, Runx-2, OPG, and OPN mRNAs in BMSCs. The differences were all significant (P<0.05).Conclusion3D printed Ti6Al4V-4Cu alloy can promote RAW264.7 cells to secret VEGF-a and BMP-2 by releasing copper ions, thus promoting osteogenesis through bone immune regulation, which lays a theoretical foundation for the application of metal prosthesis.