| [Background]Reconstruction of mandibular defects due to trauma, tumor, congenitalmalformations, infections and other causes is a common clinical problem. Attached toa large muscle, ligament mandible is the only active portion of the bone, the morecomplicated its structure, the surface is1/3of the contour of the main components,and talking, chewing, swallowing oral function closely related. Mandibular defectsnot only affect the patient’s face shape, but also seriously affect the mental health ofthe patient.Under a large segment of the mandible defect has been a major problem in oraland maxillofacial surgeon faces. Autologous bone graft mandibular defects better, butpoor shape, with limited bone volume, unable to meet the repair larger defects, andautogenous bone graft donor site anatomy often cause damage to the structure andfunction, increasing the suffering of patients.Therefore, it requires us to seek a new reconstruction method. In recent years,the development of bone tissue engineering for reconstruction of mandibular defectsprovides another method, but currently used in bone tissue engineering scaffoldstrength is difficult to achieve clinical requirements, but also more difficult to restorethe shape of the mandible.[Objective]In order to solve a large segment of mandibular defect reconstruction to repairthe problem, by establishing an animal model than under Beagle hemi mandibulardefects, using the principles and methods of tissue engineering, innovative proposeslyophilized allograft as scaffold composite mandible allogeneic bone marrow mesenchymal stem cells to repair large section of the reconstruction program undermandibular defect, explore new ways large segment of mandibular defect repair forlarge clinical section provides experimental evidence of mandibular defect repair.[Method]1Cut beagle dogs right side of the mandible, soft tissue dissection attached, flushing,degreasing, frozen and freeze-dried, after irradiation sterilization, storage at roomtemperature. By histology, scanning electron microscopy and biomechanical bendingand compression tests to detect；2Males than among isolated and cultured canine bone marrow mesenchymal stemcells cells were cultured in vitro, osteogenic, adipogenic differentiation inducingdirection and separated by flow cytometry between bone marrow mesenchymal stemcells surface markers were identified. The lyophilized bone chips and bone marrowmesenchymal stem cells co-cultured with growth curve plotted by MTT, freeze-driedbone was observed effects on cell proliferation and growth of freeze-dried bonesurfaces using scanning electron microscopy the cells；3. Surgical removal of mandibular canine teeth than the right format, two monthsafter the incision from the estuary, next hemi mandible resection, using freeze-driedbone allograft and autologous bone repair defect, after three months by CT scan andgenerally observation to assess mandibular defect reconstruction establish an animalmodel；4Among male dogs by bone marrow-derived mesenchymal stem cells combined withfreeze-dried bone allograft transplanted into female beagle dogs heterotopictransplant, using in situ hybridization tracer transplanted stem cells in the bone tissuetransplant survival, and explore allogeneic stem cell mechanism of action；5Allogeneic normal mandible mandible with pure, freeze-dried complex autologousbone marrow mesenchymal stem cells and freeze-dried bone allograft compositemesenchymal stem cell transplantation to repair Beagles hemi-mandibular defects bycomparing postoperative1,3,6months by CT scan, gross observation, histologicaldetection, Micro-CT bone density testing and peripheral blood levels of interleukin2,4,6, relatively normal mandible with the other three groups restorative effects and immunological reactions;6Since January2008-January2014, we used lyophilized allograft compositemandibular autologous bone marrow in patients with large segments of the25casesof mandibular defect repair surgery, postoperative follow-up of6years, afterpassing CT, full panoramic radiographs, ECT bone three, physical examination toassess;7Digital surgical platform was constructed, and the use of digital surgical platformfrom January2005to January2014in our hospital maxillofacial treatment of oral andmaxillofacial surgery defects, deformities mandibular defect deformity reconstructivesurgery patients were A retrospective analysis.[Results]1.No freeze-dried bone allograft internal cell components, lyophilization of bonetissue structure is not obvious damage. Lyophilized bone bending experimentsmaximum load486.67±134.12N, the maximum displacement0.67±0.15mm andstiffness1151.67±256.46N.mm-1. Maximum load of fresh bone688.97±92.07N,1.05±0.11mm, and the maximum displacement stiffness791.83±177.79N.mm-1.Maximum load and maximum displacement fresh group was significantly higher thanthe lyophilized group (P <0.01) and stiffness was significantly lower than thelyophilized group (P <0.05).2. Compression test, the compression test of fresh bone maximum load5079.5±1014.98N,1.01±0.16mm and a maximum displacement stiffness9837.83±1580.63N.mm-1. Freeze-dried bone compression test of the maximum load5163.10±730.16N, the maximum displacement of0.78±0.19and stiffness11069.17±1758.12N.mm-1. Compression fracture site of experiments in the lingual cortical boneis relatively weak at. Experimental results show the maximum compressive load offresh and freeze-dried bone group, no significant difference compared to the stiffness(P>0.05), while the maximum displacement fresh group was significantly higher thanthe lyophilized group (P <005.);2None of bone marrow mesenchymal stem cells cells1,3,6cells proliferationbetween significant differences, bone marrow mesenchymal stem cells by flow cytometry after surface markers, CD90, CD105, CD73-positive, CD45, CD34,CD31, CD14and HLA-DR was negative, showing a mesenchymal stem cellcharacteristics. Sweep surface electron microscopy showed cells sticking to thesurface of the bone tissue growth, cell proliferation and growth curve showed littlefreeze-dried bone allograft for allogeneic bone marrow mesenchymal stem cells;3. By CT scan and general observation, autologous bone and freeze-dried boneallograft to repair under beagles hemi defect, successfully constructed an animalmodel Beagles hemi-mandibular defects;4.3months after the stem cell transplant allograft composite group can detect Ychromosome-specific gene fragments, which are not shown in the control group.Description transplanted bone marrow mesenchymal stem cell survival in the bonetissue and involved in the formation of new bone.5.3and6months after surgery, compared to beagle dogs euthanized each groupwere sacrificed3, by general observation and CT scan showed pure freeze-driedbone, holes are not obvious signs of bone surface, osteoblasts slow; and lyophilizedbone and autologous stem cells and allogeneic stem cell group to absorb significantbone, osteoblasts faster bone surface hole has healed. Histology showed1,3,6monthsosteogenesis speed and freeze-dried bone allograft, autologous stem cell group werebetter than the blood vessels into bone lyophilized bone group. After6months, thedensity of data between the four groups was the result of microvascular: freeze-driedbone allograft group+was no significant difference (P>0.05) between the two groupsof microvascular density and allogeneic stem cells from stem cells, but more than thannormal mandible group (P <0.05), and freeze-dried bone allograft alone microvesseldensity was significantly less than the other three groups ((P <0.05).1,3,6May4groups drawn Beagles peripheral blood, detection of interleukin2,4,6levels, theresults showed: April4groups interleukin2,4,61,3,6seen no significant difference(P>0.05). Micro-CT after June4groups of bone tissue mineral density testingshowed pure freeze-dried bone allograft bone mineral density compared with theother three groups were significantly lower (P <0.05) by. No freeze-dried boneallograft between autologous and allogeneic stem cell group two significant differences (P>0.05), a composite of two groups of stem cells with normal bonemineral density compared to the mandibular group no significant difference (P>0.05). Preoperative and postoperative CT volume measurement of the mandible, acomparative analysis of the mandible changes in the volume of four groups. Theresults showed that pure freeze-dried bone allograft, freeze-dried bone allograft,autologous and allogeneic stem cell group were significantly reduced volume (P<0.05), a simple freeze-dried bone allograft, freeze-dried bone allograft combinedwith autologous and allogeneic no significant differences between the three groups ofstem cells in a volume group (P>0.05).6. Freeze-dried bone allograft combined with autologous bone marrow to repair largesection of25patients with mandibular defect, after review (up to6years ofobservation), in addition to bone graft in1patient due to the mucous membranes inthe mouth ulceration and infection, healed after treatment, local absorption, all otherpatients healed mandible, face a good recovery, patient satisfaction, seriouscomplications.7. In the personal computer data will be obtained by the image acquisition devicewith a variety of software with a variety of output devices knot image segmentation,quantitative measurement, simulation surgery, prosthesis production, surgicalnavigation, surgical success to build digital platforms; surgery and use of digitalplatform between January2005to January201412patients with mandibular defectreconstruction surgery, patients face type significantly improved wound healing,patients were satisfied.[Conclusion]1Freeze-dried bone allograft by physical and chemical methods clear enough cellsafter treatment of bone tissue, and can satisfy the large segment of the mandible defectbiomechanical requirements, is an excellent in vivo tissue engineering scaffolds;2Successfully constructed an animal model than under Beagle hemi mandibulardefects;3Y chromosome markers by allogeneic bone marrow mesenchymal stem cellscombined with freeze-dried bone allograft transplantation in vivo showed that the transplanted stem cells involved in bone formation;4With bone marrow-derived mesenchymal stem cells allogeneic bone remodelingrate than did cells in allogeneic bone plus obvious from the host bone healing is totransplant bone from around the central tube from Harvard to the surrounding gradualprocess of creeping substitution.5Mandible following allogeneic lyophilized scaffold composite allograft bonemarrow mesenchymal stem cells can accelerate bone graft vascularization andpromote new bone formation;6Allogeneic transplantation for reconstruction of the mandible mandibular defect bya large segment of long-term clinical follow-up observation, no rejection, facesatisfactory recovery, and gradually into the bone healed well, can be used as anoption under clinical repair of mandibular defects;7Digital surgical platform will mutually integrate the different data image processedto identify the data in different formats, different software and hardware featurescombine to play a role to help preoperative diagnosis, treatment planning, assistedsurgical implement can shorten surgery time, provide strong technical support forhealth, education, and research work. |
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