| Objective To observe destruction of lesions created in ablating tibias of the swine limbs in vivo with multi-polar radiofrequency and injury extent of soft issue arround it, repair process of lesions and maging findings of it.To discuss destruction mechanism of radiofeqency ablation(RFA),Actual effectiveness and influence on sofy tissue around lesions and experimental swine,and to give reference for treating bony tumor. Methods Six swines in vivo, Taged in order for A,B,C,D, E and F. During anesthesia, RFA was performed with DSA guidance in the diaphysis and the upper end of their tibias and femurs in different time according to condition designed in advance, then the swines were executed by depth anesthesia In the immediate time, on the third day, on the tenth day, twenty-fourth day,fifth week, the eighth week and The twelfth week after RFA,their bilateral tibias were dislodged as corresponding time samples.And in the process,X-ray and CT examination were performed on the third day, on the tenth day, twenty-fourth day,fifth week, the eighth week and The twelfth week after RFA.Specimens is immediately fixed by 10% formalin liquid,observated by Naked eye and measureed.then they is sended to pathological room and made into biopsy (HE dyeing), pathological sections was attentively observated under microscope. Results First,to observate instantly samples after RFA, central area of lesion is coagulative necrosis, its shape is oval, and its colour is hoar. Toward outside of it, there is hyperemia and bleeding area,whichcolour is puce and which width is unequal and 0.15cm～0.25cm. Again toward utside,Organizational structure is normal there. Second,the size of coagulative necrosis aria is 2.71cm×1.71cm in which is central area of lesion of bone end in instantly specimens after RFA, and long axis of coagulative necrosis aria is parallel to needle way of RFA. To observe by microscope,the bone which is close to needle way in coagulative necrosis aria is completely and directly destroyed, part of marrow tissue loses its organization form and is broken into vague, structureless and granular substance. Toward outside, bone rabeculae form don't chang, form of bone cells in bone rabeculae don't almost chang,acidophilia of marrow tissue enhances and is dyed to crimson. Toward outside again,organization form there is normal. Thirdly, the size of coagulative necrosis aria is 4.64cm×2.20cm in which is central area of lesion of diaphysis in instantly specimens after RFA, and long axis of coagulative necrosis aria is parallel to tibia. To observe by microscope, A few marrow tissue which is close to needle way in coagulative necrosis aria is broken into vague, tructureless and granular substance. Form of most marrow tissue don't change almost,And cidophilia of it enhances and is dyed to crimson. Toward outside again organization form there is normal.Fourthly, destruction of RFA for compact bone of bone end and diaphysis is restrict,and 0.01cm compact bone from Needle way is destroyed under microscope. The compact bone close to coagulative necrosis aria and Soft tissue outside it don't changeabnormally.Fifthly, there is inflammatory reaction in hyperemia and bleeding area of lesions created by RFA from 1 to 3 days after RFA. Inflammatory reaction form granulation tissue from 3 to 10 days after RFA, then granulation tissue decomposed and absorbed necrotic tissue gradually towards inner, and matured gradually for fibrous tissue according to it formed order, the low density bone absorption band was observed in x-rays and CT imaging finding to 24 days after RFA,and later on it widened following granulation tissue decomposing and absorbing necrotic tissue gradually towards inner.New bone was The first form of fibrous tissue ocated at the edge of the ablation of lesion. Bone hyperplasia sclerosis belt close to rim of absorbs area was observed in in x-rays and CT imaging finding and it widened As time goes on. more obvious repairs were observed from 5,8,12 weeks specimens, The ow density absorption area of bone end reduced and medullary cavity narrowed on account of Bone hyperplasia sclerosis.There was reactive osteogenesis in the outer periosteal close to ablation lesions,and it further formed spindle bone in periosteum.Sixthly, fractures of the femoral and tibial diaphysis happens possibly after RFA without effective braking. Conclusion First, RFA can effectively damaged spongy bone and marrow tissue, marred range of spongy bone caused directly by RFA is slightly smaller than for that of the soft tissue, marred range of marrow tissue along longitudinal axis of long bones is slightly longer than that of the soft tissue,but directl destruction of RFA to bone is Limited.Second, complete compact bone can effectively block heat conduction, necrosis was not observed in the soft tissue outside the dense bone when RFA was performed inside it. Thirdly, structural form of bone in lesions caused by RFA was almost normal early after RFA,but its function lost alreadly, it begined to solidify and solve soon after,this change is different from that of soft tissue after RFA. Fourth,inflammatory reaction and fibrous repair appeared in hyperemia and bleeding area of lesions rim from 1day to 3 days after RFA, fibrous repair did to 10 days after RFA and osseous repair did to 4 weeks after RFA. Fifth, Blood supply adjacent to lesions was destroyed and may cause the blood supply obstacles.It can cause osteonecrosi and maked actual necrotic area significantly greater than necrosis range caused directly by RFA. Sixth,RFA can effectively damaged bone tumors, and can be used in the clinical treatment of bone tumor. |
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