Study Of Percutaneous Vertebroplasty During Osteoporotic Vertebral Compression Fracture

Objective1．To probe expression of VEGF and collagenⅠtype in interface between polymethylomethacrylate (PMMA) and bone tissue after percutaneous vertebroplasty(PVP) .In order to evaluate repairing ability of bone tissue around bone cement from molecular level after percutaneous vertebroplasty in osteoporotic vertebral comp-ression fracture (VCF) patients and provide theory and experimental evidence for total evaluation effect of PMMA on human body and material degradation.2．Repairing of rabbit vertebral bone defect after injection PMMA in PVP was observed. In order to provide morphological evidence for effect of PMMA on body and material degradation3．Biomechanics change was observed countiously after injection PMMA in rabbits, comparing the differences among the normal group, the osteoporotic group and the experimental group, in order to understand the relative of biomechanics and bone biological alteration.4．Morbidity of osteoporotie fracture was investigated form sexual, age, illness date and three kinds of osteoporotie fracture in hospital patients, in order to afford many epidemiology evidences for prevention of the kind of disease.METHOD1．Vertebral local biological alteration after PVP(1) The bone defect of 0．3cm×0．3cm×0．3cm in vertebral body was made in 72rabbits.PMMA were implanted into the lumbar vertebral body by PVP in 36 rabbitsrespectively.X-ray of lumbar vertebral was detected on lateral and positive side at postoperation immediately and died before respectively.VEGF and CollagenⅠmRNA in bone tissue of interface between bone cement and bone tissue were detected through real-time PCR and Western blot ways at 1h, 24h, 3d, 7d, 4w and 12w after operation.Comparision the difference of expression to the osteoporotic group had been done. Additionally, proliferation of around bone tissue was studied by HE stain on which supplied morphological evidences.(2) The no accessories vertebral body were selected at at 1h, 24h, 3d, 7d, 4w and 12w after PMMA was implanted into rabbit's lumbar vertebral body and the most load, stress and elastic mode were detected through bending experiment. Change of vertebral biomechanical ability among the normal group ,osteoporotic group and the operation group were compared.2．Investigation for morbidity of osteoporotic fractureAccording to epidemiology requirement, 5987 osteoporotic fracture cases werecollected from 10 hospitals in our country retrospectively. Date was analyzed fromsexual, age, illness date and three kinds of osteoporotic fracture ratio aspect.RESULT1．Vertebral local biological alteration after PVP(1) Expression of VEGF at 1h, 24h group was lower than the contrast group andhigher at 3d, lower again at 7d, but from 4w to 12w period, expression of VEGFalways high. On the other hand, expression of CollagenⅠtype was higher from 24hto 3d, decrease at 7d. But from 4w to 12w period, expression of CollagenⅠtype wasalways higher.(2) Inflammation was famous more and more from 1 hour to 7 days postoperation,then decrease at 7 days. Active proliferation of cartilage was observed at 4w group,bone tissue formation at 12 weeks postoperation too.(3) Bending test shown: The value of the most load, stress and elastic mode were different among osteoporotic group, normal group and PMMA group. The last one was the strongest. But the value was different at each stage.2．Investigation for morbidity of osteoportic fracture(1) There were many osteoporotic hip fracture patients from 65 to 79 years old, about owning 63．48 percent of total steoporotic hip fracture cases; Female is higher than male, about owning 65．14 percent (P<0．001) .There were many osteoporotic vertebral fracture patients from 60 to 74 years old, about owning79．36 percent of total steoporotic vertebral fracture cases;But ratio of male osteoporotic fracture patients was higher than females from 60 to 64 years old,about owning 45．45 percent. View from sex, the morbidity of females was higher than the male but there was no statistic difference (P>0．05) . The third kind of osteoporotic fracture: lots of patients were 60 to74 years old, about owning 81．21 percent. The females had high morbidity than male but the vaule of "P"was 0．052 .We could not decide if there was difference between them.(2) Analysis from illness date, there were no famous difference among all kinds of osteoporotic fracture patients (P > 0．05 ) . But, especially, there were many osteoporotic hip fracture cases in northern area in spring, but in southern in winter area.We found that there was famous statistic difference (P<0．001) .CONCLUSION1．Biological aspect after percutaneous vertebroplasty(1) PMMA implanting into vertebral body led to inflammation reaction but there was no lasting ischemic necrosis. Inflammation reaction would decrease after seven days and disappear after twenty-eighty days respectively.(2) There were famous expression of VEGF and collagenⅠtype in interface between PMMA bone cement and bone tissue.(3) Repairing course in interface between bone cement and bone tissue was as same as normal fracture healing,but delaying for 4 weeks.(4) PMMA was a kind of ideal bone cement and remodel biomechanics quickly.(5) Increasing biocompatible ability, decreasing side effect is a kind of trend in researching perfusion material field.2．Investigation for morbidity of osteoportic fracture(1) Osteoporotic hip fracture was the most osteoporotic fracture type in hospital.The female patients is more than male.(2) There were lots of osteoporotic fracture cases from 65 to 79 years old people. Quantity of osteoporotic vertebral compression fracture was still highly.(3) There were no famous seasonal different of morbidity among all kinds of osteoporotic fracture patients. But there were famous differences in osteoporotic hip fracture. Especially, there were many osteoporotic hip fracture cases in northern area in spring, but in winter in souther area in China.