【Abstract】 Objective To evaluate the feasibility and effectiveness of reconstruction of mandibular bone defects using three-dimensional skull model and individualized titanium prosthetics from computer assisted design. Methods Between July 2002 and November 2009, 9 patients with mandibular defects accepted restorative operation using individualized bone prosthetics. Among 9 cases, 4 were male and 5 were female, aged 19-55 years. The causes of mandibulectomy were benign lesions in 8 patients and carcinoma of gingival in 1 patient. Mandibular defects exceeded midline in 2 cases, involved condylar in 4 cases, and was limited in one side without involvement of temporo-mandibular joint in 3 cases. The range of bone defects was 9.0 cm × 2.5 cm-17.0 cm × 2.5 cm. The preoperative spiral CT scan was performed and three-diamensional skull model was obtained. Titanium prosthetics of mandibular defects were designed and fabricated through multi-step procedure of reverse engineering and rapid prototyping. Titanium prosthetics were used for one-stage repair of mandibular bone defects, then two-stage implant denture was performed after 6 months. Results The individualized titanium prosthetics were inserted smoothly with one-stage operative time of 10-23 minutes. All the cases achieved incision healing by first intention and the oblique mandibular movement was corrected. They all got satisfactory face, had satisfactory contour and good occlusion. In two-stage operation, no loosening of the implants was observed and the abutments were in good position with corresponding teeth which were designed ideally before operation. All cases got satisfactory results after 1-9 years of follow-up. At last follow-up, X-ray examinations showed no loosening of implants with symmetry contour. Conclusion Computer assisted design and three-dimensional skull model techniques could accomplish the design and manufacture of individualized prosthetic for the repair of mandibular bone defects.
Objective To investigate the effect of astragalus polysaccharides(AP) on chitosan／polylactic acid(AP／C／PLA)scaffolds and marrow stromal cells(MSCs)tissue engineering on periodontal regeneration of horizontal alveolar bone defects in dogs． Methods MSCs were isolatedfrom the bone marrow and then cultured in conditioned medium to be induced to become osteogenic．The MSCs were harvested and implanted into AP／C／PLA and C／PLA scaffolds．A horizontal alveolar bone defect(5 mm depth, 2 mm width)were produced surgically in the buccal side of the mandibular premolar 3 and 4 of 10 dogs．The defects were randomly divided into 4 groups(n=10)：Group A, root planning only(blank contro1); group B, AP／C／PLA with conditioned medium(medium contro1);group C, C／PLA with MSCs(scaffolds contro1); and group D, AP／C／PLA with MSCs(experimental group)．Eight weeks after surgery， block sections of the defects were collected for gross, histological and X-ray analysis. Results MSCs induced in vitro exhibited an osteogenic phenotype with expressingcollagen I and alkaline phosphatase． X-ray film observation showed that the bone density and height had no changes in group A; in group B, the bone density was increased to a certain extent and furcation area reached a few height, but no height was increased in interdental septum; in group C，the bone density was increased and furcation area nearly reached the native height,but interdental septum reached a few height;in group D,the bone density was increased significantly and furcation area and interdental septum reached the native height. Histological evaluation showed that there was greater tissue formation in group D than that in groups A, B and C, in which new alveolar bone, new cementum, periodontal ligament with Sharpey’s fibers, and new bone tissue was similar to native periodontal tissues. Ingroup A，B, C and D respectively, the amount of new alveolar bone regeneration was 0.83±0.30, 1.46±0.55, 2.67±0.26 and 2.90±0.41 mm; new cementum regeneration was 0.78±0.45，1.30±0.60，2.29±0.18 and 2.57±0.22 mm; the amount of connective tissue adhesion was 0.80±0.22，1.33±0.34，2.23±0.42 and 2.64±0.27 mm; all showing significant differenecs between group D and groups A, Band C (Plt;0.05)．Conclusion The technology of tissue engineering with AP／C／PLAscaffolds and induced MSCs may contribute to periodontal regeneration．
Objective To evaluate the limbs shortening and re-lengthening in the treatment of tibial infectious bone defect and chronic osteomyelitis. Methods Between January 2011 and April 2016, 19 cases of tibial infectious bone defect and chronic osteomyelitis were treated with the limbs shortening and re-lengthening technique. There were 13 males and 6 females, aged from 22 to 62 years (mean, 44 years). The causes of injury included traffic accident injury in 16 cases, crush injury in 1 case, and falling from height in 2 cases. One patient was infected after plate internal fixation of closed tibial fracture and 18 patients after external fixation of open tibial fractures (Gustilo type IIIB). The mean previous operation times was 3 times (range, 2-5 times). The time from injury to bone transport operation was 3-11 months (mean, 6.5 months). The bone defect length was 2.0-5.5 cm (mean, 4.3 cm) after debridement. After tibial shortening, limb peripheral blood supply should be checked after release of the tourniquet. Seven wounds were closed directly, 5 were repaired with adjacent skin flap, 5 were repaired with sural neurovascular flap, 1 was repaired with medial head of gastrocnemius muscle flap, and 1 underwent skin grafting. Single arm external fixator or ring type external fixator were used, and completely sawed off between 2 sets of external fixation screws at proximal and distal metaphysis of the tibia. Limb lengthening was performed after 1 week with the speed of 1 mm/d. Results All patients were followed up 10-36 months with an average of 14 months. Two cases delayed healing of the wound after operation, and the other wounds healed primarily. Natural healing of the opposite end of the bone were found in 18 cases, and 1 case had nonunion in the opposite end of the bone because of incomplete removal of lesion bone. There were 5 cases of slow growth of the callus, and healed smoothly by " accordion” technology and injecting red bone marrow in 4 cases, and by bone grafting and internal fixation in 1 case. The time of bone lengthening was 1-3 months, the prolongation index was 1.6-2.7 cm/month (2.20 cm/month). The bone healing time was 7-13 months (mean, 11.1 months). According to tibial stem diagnostic criteria Johner-Wruhs score, 9 cases were excellent, 8 cases were good, 2 cases were fair, with an excellent and good rate of 89.5%. Conclusion Limbs shortening and re-lengthening is an effective method for the treatment of tibial infectious bone defect and chronic osteomyelitis, with the advantages of improving the immediate alignment of the osteotomy ends, significantly shortening the bone healing time of opposite ends of bone.
Objective To investigate the expression levels and significance of vascular endothel ial growth factor (VEGF) and microvessel density (MVD) in rabbit radius defects repaired with allogeneic and autogenic bone. Methods Forty adult New Zealand rabbits were chosen, and 10 mm bone defect model was created in the bilateral radii of 28 experimental rabbits. The other 12 rabbits provided allogeneic bone under the standard of American Association of Tissue Bank. In the left side, allogeneic bone were used to repair bone defect (experimental group), equal capacity autogenous il iac bone was used in the right side (control group). Animals were sacrificed at 2, 4, 8, and 12 weeks postoperatively. Immunohistochemical method was used to determine the expression of VEGF, CD34 protein and MVD counting. Bone histomorphometric parameters, including percent trabecular area (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp) were measured by von Kossa staining undecalcified sl ices. The relation was analyzed between VEGF and MVD, histomorphometric parameters. Results The positive signals of VEGF protein were detected in cytoplasm of vascular endothel ial cells, chondrocytes, osteoblasts, fibroblasts and osteoclasts. At 2 weeks, there was no significant difference in VEGF protein expression between experimental group and control group (P gt; 0.05); at 4 and 8 weeks, the expression of VEGF in control group was significantly higher than that in experimental group (P lt; 0.05); and at 12 weeks, there was no significant difference between two groups (P gt; 0.05). There was a positive correlation (P lt; 0.01) between VEGF expression and MVD value in two groups at 2, 4, 8, and 12 weeks postoperatively. There was no significant difference in bone histomorphometric parameters (BV/TV, Tb.Th, Tb.N, Tb.Sp) between two groups at 12 weeks postoperatively (P gt; 0.05), but there was a positive correlation between VEGF expression and parameters of BV/TV, Tb.Th, and Tb.N (P lt; 0.01); and a negative correlation between VEGF and Tb.Sp (P lt; 0.01). Conclusion VEGF can express diversity at different time and positions, and the different expressions indicated various biology significances in the process of the bone heal ing. It can coordinate growth of cartilage and bone and profit vascular reconstruction of allogeneic bone. VEGF may participate in promoting osteogenesis in the course of allogeneic bone transplantation.
【Abstract】 Objective To investigate the anti-infection and bone repair effects of cationic l i posome-encapsulatedvancomycin combined with the nano-hydroxyapatite/chitosan/konjac glucomannan (n-HA/CS/KGM) composite scaffold invivo. Methods Fifty-one 6-month-old New Zealand white rabbits, weighing 1.5-3.0 kg, were selected to prepare chronicinfectious tibia bone defect model by using Staphylococcus aureus. After 4 weeks, 48 survival rabbits were randomly divided into 4 groups (n=12). After debridement, defect was treated with nothing in group A, with n-HA/CS/KGM composite scaffold in group B, with vancomycin and n-HA/CS/KGM composite scaffold in group C, and with cationic l i posome-encapsulated vancomycin and n-HA/CS/KGM composite scaffold in group D. After 8 weeks of treatment, general observation, X-ray, HE staining, the bacterial culture, and the measurement of the longest diameter of bone defect were done. Results At 4 weeks after modeling, 48 rabbits were diagnosed as having osteomyelitis, including periosteal new bone formation, destruction of bone, and soft tissue swell ing. The Norden score was 3.83 ± 0.52. At 8 weeks after treatment, sinus healed in groups C and D, but sinus was observed in groups A and B; the gross bone pathologieal scores of group D were significantly better than those of groups A and B (P lt; 0.05). Bone defects were repaired completely in group D, the results of the longest diameter of bone defects in group D was significantly better than those in the other 3 groups (P lt; 0.05). New bone formation was observed in groups C and D, but periosteal reactionand marrow low-density shadow were observed in groups A and B; Norden score in group D was significantly better than those in groups A, B, and C (P lt; 0.05). HE staining showed that there were a large number of trabecular bone formation and fibrosis, with no obvious signs of infection in groups C and D, but neutrophil accumulation was observed in groups A and B; Smeltzer scores in groups C and D were significantly better than those in groups A and B (P lt; 0.05). Bacteriological results showed higher negative rate in groups C and D than in groups A and B (P lt; 0.05). Conclusion Cationic l iposome-encapsulated vancomycin and n-HA/CS/KGM composite scaffold can be a good treatment for infectious bone defects in rabbits, providing a new strategy for the therapy of bone defects in chronic infection.
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.
Objective To investigate the effectiveness of tissue flap grafting and sequential bone lengthening for repairing severe soft tissue and bone defects of the lower extremity after burn injury. Methods Between January 2010 and December 2015, 11 cases of large segmental bone and soft tissue defects in the leg were treated. There were 10 males and 1 female, with a mean age of 28 years (range, 19-37 years). The causes included traffic accident in 8 cases, high voltage electric burn in 2 cases, CO poisoning burn in 1 case. The time from injury to admission was 3-14 days (mean, 6.5 days). The bone defect length was 8-18 cm (mean,14 cm); the skin soft tissue defect ranged from 13 cm × 8 cm to 25 cm × 19 cm. After complete removal of necrotic tissue and lesions of the femur or the tibia, the tissue flaps were used to repair soft tissue defect of the lower extremity in one-stage operation; bone defect was treated by Orthofix single side external fixation or Ilizarov ring external fixation in two-stage operation. Results Eleven flaps survived completely, primary healing of incision was obtained in the others except for 1 patient who had necrotic bone infection, which was cured after removing necrosed femoral bone and filling with antibiotic bone cement spacer. During bone lengthening, pin tract infection occurred in 1 patient, and infection was controlled after dressing change. Bone lengthening ranged from 8 to 18 cm, with an average of 14 cm. After prolonged extension, the external fixator was retained for 4-12 months (mean, 6.5 months). All bone defects were repaired with bone healing time of 12-22 months (mean, 17 months). All patients were followed up 8-24 months (mean, 15 months). No vascular and neurological complication occurred during operation; no osteomyelitis or re-fracture occurred after operation, and the recovery of the lower extremity function was good. Conclusion Tissue flap grafting combined with bone lengthening is an effective method to repair severe bone and soft tissue defects of lower extremity.
Objective To study and prepare a new kind of bone graft, which has osteogenesis, local anti-infective function and low immunogenicity. Methods Gentamicin-impregnated bone was prepared bymeans of ultrasonic and vacuum, the release of gentamicin in vivo was measured by inhibition bacteria. Ten healthy male adult sheep were made animal infection models of thigh bone or humerus defect of 6 mm×6 mm×20 mm at size, and the defect was inoculated into 1 ml 5×1010CFU/ml Staphylococcus aureus. The animals were randomly divided into the experimental group (n=5, the bone graft with gentamicin was implanted) and the control group (n=5, the bone graft without gentamincin). Macroscopic, WBC count, radiological, and histological investigations were carried out to evaluate the antiinfective and osteosis capability. Results The concentrations of gentamicin were 46.1 μg/ml in bone allograft and 17.3 μg/ml in muscles after 1 day. The concentrations of gentamicin exceeding the minimum inhibitory concentration lastedfor 14 days in vivo. WBC in the control group was higher than that in the experimental group. In the control group, 1 case died owing to septemia 3 weeks afteroperation. The implanted bones were wrapped in pus 4 and 6 weeks, and the defects were filled with fibre tissue 8 and 10 weeks after operation. In the experimental group, 1 case was infected, the others had a good concrescence. The bone allografts began to integrate with adjacent bone after 4-8 weeks and integrate well after 12 weeks. The X-ray and histological observation showed that new bone formed and took the place of bone allograft. Conclusion The gentamicinimpregnated bone allograft was of a good sustained release feature in vivo, local antiinfection and osteogenesis. It might be an ideal bone grafting material for bone defects with infection.
Objective To study the operative methods and therapeutic effects of acetabulum reinforcement ring in the reconstruction of acetabular defects in primary and revisional artificial hip replacement. Methods From November 2000 to July 2005, 14 cases (15 hips) of severe acetabular defects in artificial hip replacement were treated with acetabulum reinforcement ring combined autogenous or allogenic bone transplantation, including 7 males and 8 females aged 34-72 years with an average of 55 years. Among them, 9 cases (9 hips) underwent artificial hip joint revision, which was 3-22 years (average8.9 years) far away from their primary replacement, and 5 cases (6 hi ps) received primary replacement, including 1 case of rheumatoid arthritis of both hips, 1 osteoarthritis caused by acetabular dysplasia, 1 femoral head resection due to debridement of hi p infection, 1 nonunion of acetabulum old fracture with the center dislocation of femoral head and 1 old acetabulum fracture. The disease course was 2-25 years (average 11.6 years). According to the American Academy of Orthopaedic Surgeons (AAOS) classification, the acetabulum defects of 7 hips were categorized into Type II, 6 hips were Type III and 2 hips were Type IV. Harris score was (59.1 ± 15.4) points preoperatively. Results All wounds were healed by first intention. The symptom of sciatic nerve simulation was occurred in 1 case and was rel ieved after taking neuroprotective drug for 5 months. All the cases were followed up for 33-90 months (average 51.3 months). Harris score at the final follow-up was (81.9 ± 10.4) points, indicating there was a significant difference between before and after operation (P lt; 0.01). X-ray film demonstrated that the displacement of acetabulum reinforcement ring and acetabular cup was less than 5 mm, the rotation was less than 5°, and there was no progressive radiolucent zone around acetabulum and screw. Conclusion Acetabulum reinforcement ring is beneficial to reconstruct severe acetabular defects, improve hip joints’ function and provide primary stabil ity for putting acetabular cup into an ideal biomechanical position.
Aiming at the problem of scaffold degradation in bone tissue engineering, we studied the feasibility that controlls bone defect repair effect with the inhomogeneous structure of scaffold. The prediction model of bone defect repair which contains governing equations for bone formation and scaffold degradation was constructed on the basis of analyzing the process and main influence factors of bone repair in bone tissue engineering. The process of bone defect repair and bone structure after repairing can be predicted by combining the model with finite element method (FEM). Bone defect repair effects with homogenous and inhomogeneous scaffold were simulated respectively by using the above method. The simulation results illustrated that repair effect could be impacted by scaffold structure obviously and it can also be controlled via the inhomogeneous structure of scaffold with some feasibility.