This study was to explore a better three-dimensional (3-D) culture method of chondrocyte. The interpenetrating network (IPN) gel beads were developed through a photo-cross linking reaction with mixed barium ions and calcium ions at the ratio of 5:5 with the methacrylic alginate (MA), which was a chemically conjugated alginate with methacrylic groups. The second generation of primary cartilage cells was encapsulated in the MA gel beads for three weeks. In the designated timing, HE stain, Alamar blue method and Scanning electron microscopic were used to determine the cartilage cells growth, proliferation and the cell distribution in the scaffolds, respectively. The expression of typeⅡcollagen was investigated by an immunohistochemistry assay and the glycosaminoglycan content was quantitatively evaluated with the spectrophotometry of 1, 9 dimethylene blue assay. Compared to the alginate control group, the deposition of glycosaminoglycan was significantly upregulated in IPN-MA gel beads with higher cell proliferation. The secretion of extracellular matrix and proliferation of chondrocyte in methacrylic alginate gel beads were higher than that in Alginate beads. Cells were able to attach, to grow well on the scaffolds under scanning electron microscopy. The result of immunohistochemistry staining of collagen typeⅡwas positive, confirming the maintenance of chondrocyte phenotype in methacrylic alginate gel beads. This study shows a great potential for three-dimensional culture of cartilage.
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.
With the widespread adoption of low-dose CT screening and the extensive application of high-resolution CT, the detection rate of sub-centimeter lung nodules has significantly increased. How to scientifically manage these nodules while avoiding overtreatment and diagnostic delays has become an important clinical issue. Among them, lung nodules with a consolidation tumor ratio less than 0.25, dominated by ground-glass shadows, are particularly worthy of attention. The therapeutic challenge for this group is how to achieve precise and complete resection of nodules during surgery while maximizing the preservation of the patient's lung function. The "watershed topography map" is a new technology based on big data and artificial intelligence algorithms. This method uses Dicom data from conventional dose CT scans, combined with microscopic (22-24 levels) capillary network anatomical watershed features, to generate high-precision simulated natural segmentation planes of lung sub-segments through specific textures and forms. This technology forms fluorescent watershed boundaries on the lung surface, which highly fit the actual lung anatomical structure. By analyzing the adjacent relationship between the nodule and the watershed boundary, real-time, visually accurate positioning of the nodule can be achieved. This innovative technology provides a new solution for the intraoperative positioning and resection of lung nodules. This consensus was led by four major domestic societies, jointly with expert teams in related fields, oriented to clinical practical needs, referring to domestic and foreign guidelines and consensus, and finally formed after multiple rounds of consultation, discussion, and voting. The main content covers the theoretical basis of the "watershed topography map" technology, indications, operation procedures, surgical planning details, and postoperative evaluation standards, aiming to provide scientific guidance and exploration directions for clinical peers who are currently or plan to carry out lung nodule resection using the fluorescent microscope watershed analysis method.
ObjectiveTo explore the effectiveness of a new point contact pedicle navigation template (referred to as “new navigation template” for simplicity) in assisting screw implantation in scoliosis correction surgery. MethodsTwenty-five patients with scoliosis, who met the selection criteria between February 2020 and February 2023, were selected as the trial group. During the scoliosis correction surgery, the three-dimensional printed new navigation template was used to assist in screw implantation. Fifty patients who had undergone screw implantation with traditional free-hand implantation technique between February 2019 and February 2023 were matched according to the inclusion and exclusion criteria as the control group. There was no significant difference between the two groups (P>0.05) in terms of gender, age, disease duration, Cobb angle on the coronal plane of the main curve, Cobb angle at the Bending position of the main curve, the position of the apical vertebrae of the main curve, and the number of vertebrae with the pedicle diameter lower than 50%/75% of the national average, and the number of patients whose apical vertebrae rotation exceeded 40°. The number of fused vertebrae, the number of pedicle screws, the time of pedicle screw implantation, implant bleeding, fluoroscopy frequency, and manual diversion frequency were compared between the two groups. The occurrence of implant complications was observed. Based on the X-ray films at 2 weeks after operation, the pedicle screw grading was recorded, the accuracy of the implant and the main curvature correction rate were calculated. ResultsBoth groups successfully completed the surgeries. Among them, the trial group implanted 267 screws and fused 177 vertebrae; the control group implanted 523 screws and fused 358 vertebrae. There was no significant difference between the two groups (P>0.05) in terms of the number of fused vertebrae, the number of pedicle screws, the pedicle screw grading and accuracy, and the main curvature correction rate. However, the time of pedicle screw implantation, implant bleeding, fluoroscopy frequency, and manual diversion frequency were significantly lower in trial group than in control group (P<0.05). There was no complications related to screws implantation during or after operation in the two groups. ConclusionThe new navigation template is suitable for all kinds of deformed vertebral lamina and articular process, which not only improves the accuracy of screw implantation, but also reduces the difficulty of operation, shortens the operation time, and reduces intraoperative bleeding.
Objective To compare the effectiveness between three-dimensional (3D) printed porous titanium alloy cage (3D Cage) and poly-ether-ether-ketone cage (PEEK Cage) in the posterior lumbar interbody fusion (PLIF). Methods A total of 66 patients who were scheduled to undergo PLIF between January 2018 and June 2019 were selected as the research subjects, and were divided into the trial group (implantation of 3D Cage, n=33) and the control group (implantation of PEEK Cage, n=33) according to the random number table method. Among them, 1 case in the trial group did not complete the follow-up exclusion study, and finally 32 cases in the trial group and 33 cases in the control group were included in the statistical analysis. There was no significant difference in gender, age, etiology, disease duration, surgical segment, and preoperative Japanese Orthopaedic Association (JOA) score between the two groups (P>0.05). The operation time, intraoperative blood loss, complications, JOA score, intervertebral height loss, and interbody fusion were recorded and compared between the two groups. Results The operations of two groups were completed successfully. There was 1 case of dural rupture complicated with cerebrospinal fluid leakage during operation in the trial group, and no complication occurred in the other patients of the two groups. All incisions healed by first intention. There was no significant difference in operation time and intraoperative blood loss between groups (P>0.05). All patients were followed up 12-24 months (mean, 16.7 months). The JOA scores at 1 year after operation in both groups significantly improved when compared with those before operation (P<0.05); there was no significant difference between groups (P>0.05) in the difference between pre- and post-operation and the improvement rate of JOA score at 1 year after operation. X-ray film reexamination showed that there was no screw loosening, screw rod fracture, Cage collapse, or immune rejection in the two groups during follow-up. At 3 months and 1 year after operation, the rate of intervertebral height loss was significantly lower in the trial group than in the control group (P<0.05). At 3 and 6 months after operation, the interbody fusion rating of trial group was significantly better in the trial group than in the control group (P<0.05); and at 1 year after operation, there was no significant difference between groups (P>0.05). ConclusionThere is no significant difference between 3D Cage and PEEK Cage in PLIF, in terms of operation time, intraoperative blood loss, complications, postoperative neurological recovery, and final intervertebral fusion. But the former can effectively reduce vertebral body subsidence and accelerate intervertebral fusion.
ObjectiveTo establish a model of three-dimensional (3-D) cephalometric analysis to study dentomaxillofacial deformities. MethodsBetween January 2012 and October 2013,15 patients with dentomaxillofacial deformities were treated using 3-D cephalometric analysis in orthognathic surgery plan.There were 7 males and 8 females with an average age of 23.6 years (range,17-37 years),including 4 cases of mandibular protrusion with maxillary deficiency,4 cases of maxillary protrusion with mandibular deficiency,2 cases of long face syndrome,and 5 cases of facial asymmetry.CT images were reconstructed by Mimics software.The anatomical landmarks were located,the reference planes and analysis planes were defined and the 3-D coordinate was established.The distance and degree between landmarks and analysis planes which defined in the measure project were measured. ResultsBased on the 3-D CT quantitative analysis methods,cephalometric analysis project was defined in the 3-D coordinate.3-D cephalometric analysis provided a convenient and precise method for the clinical measurement of dentomaxillofacial morphology,and reduce the time in preoperation analysis. ConclusionThe model of 3-D CT cephalometric analysis can provide precise information in the diagnosis and treatment planning of orthognathic surgery.
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 investigate the construction of a novel tissue engineered meniscus scaffold based on low temperature deposition three-dimenisonal (3D) printing technology and evaluate its biocompatibility. Methods The fresh pig meniscus was decellularized by improved physicochemical method to obtain decellularized meniscus matrix homogenate. Gross observation, HE staining, and DAPI staining were used to observe the decellularization effect. Toluidine blue staining, safranin O staining, and sirius red staining were used to evaluate the retention of mucopolysaccharide and collagen. Then, the decellularized meniscus matrix bioink was prepared, and the new tissue engineered meniscus scaffold was prepared by low temperature deposition 3D printing technology. Scanning electron microscopy was used to observe the microstructure. After co-culture with adipose-derived stem cells, the cell compatibility of the scaffolds was observed by cell counting kit 8 (CCK-8), and the cell activity and morphology were observed by dead/live cell staining and cytoskeleton staining. The inflammatory cell infiltration and degradation of the scaffolds were evaluated by subcutaneous experiment in rats. Results The decellularized meniscus matrix homogenate appeared as a transparent gel. DAPI and histological staining showed that the immunogenic nucleic acids were effectively removed and the active components of mucopolysaccharide and collagen were remained. The new tissue engineered meniscus scaffolds was constructed by low temperature deposition 3D printing technology and it had macroporous-microporous microstructures under scanning electron microscopy. CCK-8 test showed that the scaffolds had good cell compatibility. Dead/live cell staining showed that the scaffold could effectively maintain cell viability (>90%). Cytoskeleton staining showed that the scaffolds were benefit for cell adhesion and spreading. After 1 week of subcutaneous implantation of the scaffolds in rats, there was a mild inflammatory response, but no significant inflammatory response was observed after 3 weeks, and the scaffolds gradually degraded. Conclusion The novel tissue engineered meniscus scaffold constructed by low temperature deposition 3D printing technology has a graded macroporous-microporous microstructure and good cytocompatibility, which is conducive to cell adhesion and growth, laying the foundation for the in vivo research of tissue engineered meniscus scaffolds in the next step.
Objective To explore the feasibility and effectiveness of suture anchor double-pulley technique combined with suture three-dimensional binding via bone tunnel technique for avulsion fractures of the inferior pole of the patella. Methods A clinical data of 38 patients with avulsion fractures of the inferior pole of the patella, who met the selective criteria and were admitted between September 2021 and April 2023, was retrospectively analyzed. The fractures were treated with suture anchor double-pulley technique combined with suture three-dimensional binding via bone tunnel technique in 18 cases (group A) and steel wire tension-band fixation in 20 cases (group B). There was no significant difference in terms of age, gender, cause of fracture, side of fracture, and disease duration between the two groups (P>0.05). The length of incision, operation time, occurrence of complications, the range of motion of knee joint, and B?stman score of knee joint at last follow-up were recorded. The fracture healing was evaluated through X-ray films and the time of fracture healing was recorded. Results All incisions healed by first intention. The length of incision was significantly shorter in group A than in group B (P<0.05). There was no significant difference in the operation time between the two groups (P>0.05). All patients were followed up 12-24 months (mean, 16.1 months). X-ray films showed that all fractures healed and there was no significant difference in the healing time between the two groups (P>0.05). At last follow-up, the range of motion and B?stman score of the knee joint in group A were significantly better than those in group B (P<0.05). During follow-up, 1 patient (5.6%) in group A had one anchor mild prolapse and 3 patients (15.0%) occured internal fixation irritation in group B. But there was no significant difference in the incidence of complications between the two groups (P>0.05). Conclusion For the avulsion fractures of the inferior pole of the patella, the suture anchor double-pulley technique combined with suture three-dimensional binding via bone tunnel technique has advantages of reliable fixation, small incision, avoidance of secondary operation to remove internal fixator, and fewer complications, with definite effectiveness.
Based on the CT data and the structure characteristics of the femoral fractures during different healing stages, medical FE models of fractured femur treated with locking compression plate (LCP)were built.Under the physiological load of a standard body weight (70 kg) and the constraint condition,the stress distributions of LCP and fractured femur during healing were calculated by means of three-dimensional finite element analysis (3D-FEA).The results showed that the stress distribution in the LCP and the fractured femur was similar,during the initial stage which there was no newly formed bone or soft tissue in fracture site.The maximum von Mises stress (371.23,272.76 MPa) in the fractured femur was much higher than that in natural femur,and the intensive stress was concentrated mainly in the proximal area of the fractured femur.With the growth of bony callus bone in fracture site,the intensity of stress in proximal femur decreased.Contrasted to the two cases mentioned above,the value of the maximum von Mises stress (68.17 MPa) in bony callus bone stage decreased significantly,and was lower than the safe strength of natural bone.Therefore,appropriate training which is benefitial for the growth to new bone could be arranged for the better rehabilitation.