ABSTRACT
BACKGROUND: For its extensive sources and specific biological characteristics, heterogeneous deproteinized bone (DPB) as the tissue-engineered scaffold material gets a good application prospect in repair of large segmental bone defects.OBJECTIVE: To prepare scaffold material by compositing modified heterogeneous DPB with recombinant human bone morphogenetic protein 2 (rhBMP2) and evaluate the osteogenic ability in repairing large segmental long bone defects in large-sized animals.METHODS: Twenty-four goats were randomly and evenly divided into three groups: DPB, autologous bone, and DPB+rhBMP2. Bone defects (20% in length) were made in the middle and lower segments of the right tibia of each goat, and according to group design,different bone grafts were implanted and fixed using semi-ring slot external fixer. At 4-24 weeks after surgery, X-ray examination was performed once every other 4 weeks. At 24 weeks after surgery, newly formed bones were taken out for determining the repair effects of bone defects through duat-energy X-ray analysis, histological observation, and biomechanical analysis.RESULTS AND CONCLUSION: The prepared DPB exhibited a three-dimensional porous structure, with a porosity of (78.5±6.45)% and pore size of (472.5±7.02) μm. Time-dependent bone repair was found in each group. Results regarding anti-compression test, three-point anti-bend test, and anti-torsion test were greatest in the autologous bone group, followed by the DPB+rhBMP2 group, and lastly the DPB group. There were no significant differences in tibial bone density, bone mineral content,anti-compression pressure and ultimate pressure, anti-bending load and ultimate toad, anti-torsion torque and ultimate torque between autologous bone group, DPB+rhBMP2 group and normal bone control group. These findings indicate that modified heterogeneous DPB composited with rhBMP2 has osteogenic ability equivalent to autologous bone in repairing large segmental long bone defects in goat tibias. Therefore, it can be applied as tissue-engineered scaffold material.
ABSTRACT
BACKGROUND:Half-ring sulcated external fixator is a bone external fixation device.Its structure is relatively simple,with multi-plane fixed,and small occupying space.So far,there are few experimental reports about construction of tibial defect model by it in large animals.OBJECTIVE:To validate the practicality and repeatability of half-ring sulcated external fixator in establishing tibial defect models in goats.DESIGN,TIME AND SETTING:The randomized controlled observation was performed at the Animal Laboratory of the Third Military Medical University from March 2005 to February 2007.MATERIALS:Nine healthy adult(Animal Center of Third Military Medical University);Half-ring sulcated external fixator,made by Professor Li of the Third Military Medical University;Osseous pin,ψ2.5 mm,Shanghai Medicai Instruments Co.,Ltd.METHODS:After animals were anesthetized,two needles were threaded in the same plane of cancellous bone about 1.5-2.0 cm above the superior articular surface of the tibia,named group 1.The angle between the two needles was 40°.One needle was threaded at the place of 3.0 to 5.0 cm under the group 1 and parallel with optional needle of the group 1,named group 2.Needles of group 4 were threaded at the cancellous bone that was 2.0 cm from the joint surface of inferior extremity of the tibia.One needle was threaded at the place of 3.0 to 5.0 cm from group 4 and parallel with optional needle of the group 4.The included angle between these two needles of group 2 and group 3 was 60°.There were totally 6 needles.Tibia was fixed by half-ring sulcated external fixator.According to the length of the tibia from X-ray,tibia and periosteum were amputated by wire saw between the two needles in the middle and inferior segment of the tibia to make segmental bone and periosteal defects of 20 percent of tibia.MAIN OUTCOME MEASURES:①Postoperative general state of the animals and effect of half-ring sulcated external fixator.②Self-repair of bone defects by X-ray and Lane-Sandhu scoring standards.RESULTS:Of the 9 selected goats,1 died of postoperative infection,and 1 developed pinhole infection and supplemented.All the others survived and were included in final analysis.The goats were awake within 2-6 hours after surgery and able to stand up to eat.The loosening nuts were screwed up.No external fixation failure or loosening was found.No skin was necrotic.Injured limb could touch the ground in 2 days,but could not bear load until 2 weeks.The goats could walk in three weeks with a slight limp,then moved freely without claudication in four weeks after the operation.At the 5th week after operation,the radiographs showed little periosteal reaction.At the 10th week after operation,sclerosis was found in the fracture ends,and medullary cavity started to close.Fifteen weeks after operation,the medullary cavity closed and periosteal reaction did not aggravate.Inaddition.Lane score was 0 at any time point.No bone formation was found in the histological examination at 5,10 and 15 weeks after operation,and Lane score was 0 at any time point.CONCLUSION:The goat model established in goat tibia with 20%defects by the half-ring sulcated external fixator shows no bone healing after 15 weeks by X-ray or histological exanimation,indicating this is a practical and repetitive method to establish animal models of large segmental defect for bone tissue engineering.
ABSTRACT
We have made a biomechanical evaluation of titanium mesh with anterior plate fixation in anterior cervical decompression. Six fresh cervical spine specimens (C3-7) of young cadavers were used in the biomechanical test. Subtotal vertebrectomy was performed on C5, C5-6 and C4-6. We accomplished two constructions: (1) bone graft; (2) titanium mesh with anterior plate fixation. Then their biomechanic stabilities were tested in all groups and compared with those of intact specimens. We found that titanium mesh with anterior plate fixation improved the stability of the unstable spine, showing a significant difference when compared with that of the intact group (P < 0.05). The anterior cervical interbody fusion by bone graft and the titanium mesh implantation is stabler than the intact cervical sample, and the stability decreases with the increase in number of cervical segment.
Subject(s)
Humans , Biomechanical Phenomena , Cadaver , Cervical Vertebrae , General Surgery , Decompression, Surgical , Methods , Internal Fixators , Spinal Fusion , Methods , Stress, Mechanical , TitaniumABSTRACT
[Objective] To study the results of three dimensional orthomorphia treatment of king type Ⅲ idiopathic scoliosis transthoracic anterolateral.[Method]From Sep.2003 to Sep.2005,clinical data of applications of TSRH,CDH-M8 to 12 patients of king type Ⅲ adolescent idiopathic scoliosis transthoracic anterolateral were investigated with practicing ertebral solution centrum,centrum three dimensional orthopedic,bone graft fusion internal fixation,and analyzing and to appraising their operation complications,scoliosis correction rats and follow-up results.[Result]Postoperative complications of bellows were found in two examples,one was pulmonary closure and one was respiratory tract obstruction,and they had been soothed by trachea cannula and assistor respiration of respirator.[Conclusion]There weren't injury of great blood vessel,spinal injury,pneumonia and chylothorax in all cases.Cobb's angle of thoracic vertebra was 48?～66? preoperatively,and the average was 52.6?.The average Cobb's angle of remnant vertebra was 15.2? postoperatively,the rectification rat was 77.8%.The follow-up ranged 12 to 36 months,12 patients of king type Ⅲ gained good segment bone fusion.The complications of pseudarthmsis,internal fixation loosening and fracture and broken compensation haven't been found.Three dimensional orthomorphia treatment of King type Ⅲ idiopathic scoliosis transthoracic anterolateral is a safe and effective method of internal fixation.