| Comparing the effect of the pedicle fascial flap to osteogenesis after improving the stability with that before,using the pedicle fascial flap as the membrane guided material,with which wraps the uncellular tissue engineering bone complex to repair supercritical bone defect,by membrane guided bone regeneration techinque.Providing references for the clinical that using the pedicle fascial flap as the leading membrane to repair supercritical bone defect by membrane guided bone regeneration techinque.Conducting a centimetre long bone defect model with periosteum in the middle of both ulnas of30New Zealand rabbits. Preparing the uncellular tissue engineering bone by implanting the autologous red bone marrow to the osteoinduction active material with bone morphogenetic protein and filled the bone defect of both sides with it. Preparing a pedicle fascial flap with capillary network subordinated to an unknown vascular near the bone defect of both sides by microsurgical technique,which was made into a cylinder shape barrel to wrap the uncellular tissue engineering bone. The left side was wrapped by pedicle fascial flap merely as Group A (control),and the internal fixation with miniature titanium board was performed in the right side besides the pedicle fascial flap wrapping as Group B (experimental group).Feeding and infection prevention were performed after the operation.The X-ray of the radius and ulna was performed in both sides after four,eight,twelve and sixteen weeks to observe the imaging feature of the implanted engineering bone in the process of bone defect repair on different time point. Six animals were killed on the weeks number4,8,12,16observing the changes on the surface of the tissue engineering bone,the bone defect repair and the tissue responses and then made the pathological section as a sample to observe the changes of the pedicle fascial flap and the conditions of the tissues nearby.Finally according to the Lane-Sandhu bone graft histology score method determined the new bone trabecular area ratio of repair area under microscope of the two groups on each time point to compare the bone formation of the implant between the two groups.Executed3animals on12and16weeks after the operation to draw fresh ulnar shaft and performed the three point bending test by HY-3080biomechanical machine to measure the mechanical stiffness of the bone defect repair area.The statistical treatment of the data was processed by SPSS13.0to analyse the bone defect repair of the two groups by the experiment above and statistical results.After the operation there were two animals with unilateral limb incision swelling and exudation (one each in experimental group and control group) and the incision infections area improved after Iodophor washing, dressing and anti-infective therapy and there was no death of the animal.The incison of the other animals healed by first intention. Morphology observation:in Group A on the4th week there was light yellow translucent membrane tissue on the surface of the implant without callus,there was fibrous connection between the implant and the bone bed. Being touched, it moved slightly;on the8th week there was external callus growing since the two ends to the center,the membranous tissue covered the surface of the implant and there was cartilage like tissues in the bone graft junction;on the12th week there was more external callus forming than before but without ring package, the callus was not fully mature and the implant did not fully degradated;on the16th week the bone graft area had been completely wrapped by callus like a ring,membranous tissues could be still seen and had a blurred boundary with the surrounding tissues;while in Group B on the4th week there was a large amount of external callus on the steel plate and the bone graft area growing since the two ends to the center and part of the steel plate was wrapped by the callus.After taking out the steel plate the fascia could be seen attaching to the implant surface like pale yellow periosteal tissue and there was cartilage like tissues on the bone graft junction;on the8th week there was obvious external callus in the bone defect area,after taking out the steel plate part of the callus under the steel plate became mature there was bone bridge striding the bone repair area and most of the bridge healed with the osteotomy section and the bone graft had been completely wrapped by callus; on the12week the bone graft area was wrapped by the mature callus completely,the callus became mature,filled the bone defect area completely and part of the bone shaft structure had formed; the bone graft area disappeared completely,the bone shaft had formed and the marrow cavity was unobstructed.Histological examination:on the4th week after the operation the fascia in the two groups formed periosteal structure obstructing the surrounding soft tissues to grow into the bone defect repair area.There was a small amount of degradated and scattered developing bone trabecula and cartilage cell clusters in and around the implant.The implanted material had began to degradate.There were less degradated materials in Group A while much more in Group B;on the8th week after the operation there were bone trabecula and cartilage cell clusters forming in the tissues in Group A while in Group B there were much more bone trabecula and cartilage cell clusters;on the12th week after the operation in the Group A, part of the implant material was still not absorbed and cartilage and new bone trabecula formed but didn’t transformed into lamellar bone while in Group B,the implant material was absorbed completely,a large amount of cartilage tissues and new bone trabecula formed,part of the new bone transformed into lamellar bone from disorganized trabecula and part of the marrow cavity became recanalized;on the16th week after the operation, in Group A,the material had been absorbed and a large amount of cartilage tissues and some mature lamellar bone could be seen while in Group B,a large amount of lamellar bone could be seen and the cartilage tissues were less than that of Group A.Imaging examination:on the4th week after the operation,in Group A the stripes of the implant was clear,the bone density declined,the space between the implant and the osteotomy section could be seen clearly and there was no obvious callus while in Group B,the stripes of the implant was blurred,the bone density declined obviously,the space between the implant and the osteotomy section was not obvious and the callus had formed on the steel plate and bone graft area;on the8th week after the operation, in Group A the stripes of the implant was blurred,the bone density declined obviously,the space between the implant and the osteotomy section was blurred and there was a small amount of the callus while in Group B,there was mature callus forming on the surface of the bone graft area and in the space between the implant and the osteotomy section and there was much more external callus;on the12th week after the operation, in Group A part of the callus formed on the surface of the bone graft area and wrapped the implant and the residual implant could still be seen while in Group B,continuous external callus wrapped the bone graft area part of the bone shaft formed preliminarily,the cortical bone was connective and part of the marrow cavity became recanalized;on the16th week afte the operation, in Group A contiuous external callus wrapped the surface of the bone graft area and the bone shaft structure formed preliminarily, the cortical bone was not connective and the marrow cavity was not unobstructed while in Group B,the normal bone shaft formed and the marrow cavity was completely recanalized. Bone histomorphometry:comparing the ratio of the new bone trabecular area with the microscopic repair area of Group B with that of Group A on the4th,8th,12th and16th week after the operation and those on the different time point in Group B,the difference had statistical significance (F<0.01).Biomechanics:on the,12th and16th week after the operation, the ulna three-point bend biomechanical measurement showed that the mechanical strength of Group B was much larger than that of Group A on the same time and the difference had statistical significance (.P<0.01);comparing the mechanical strength in the same group on different time point, the difference had obviously statistical significance (P<0.01).Using vascularized fascial flap as the membrane guided material wrapping the uncellular tissue engineering bone can separate the connective tissues,it has the effect of guiding bone regeneration and has obvious effect in the bone defect repair.After improving the pedicle fascial flap stability, the external callus formation time is much shorter than that of simple wrapping group and the quality and quantity of the callus are elevated obviously.The experiment has proved that after improving the membrane structure stability,the space under the membrane and the bone graft area are maintained better,which is beneficial to bone defect repair and providing a new and convenient method for ECSD repair in the clinical. |
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