| Malignant bone tumor was one of the common clinical malignant tumors, Which was characterized by high-grade malignant, rapid progression and low cure rate. amputation and disarticulation was the first choice for malignant bone tumor, especially stageⅡb according to Enneking stage system, however, limb-salvage treatment had gained prominence with the development of the chemotherapy and imaging technique. There were many kinds of surgeries including joint replacement arthroplasty, the same kind of massive allografts bone transplantation, replantation of resected bone tumor after decitalization and microwave-induced hyperthermia operation. what is more, microwave-induced hyperthermia operation had attracted people's attention, which was characterized by killing bone cancer cells and maintaining the role of bone scaffold material. However. It was not very difficult to control the temperature ranges unless simulating before operation. In recent years, the accuracy and safety of surgery had greatly developed because of close integration by digital medical technology and orthopaedic clinical medical.MWTps (Cool-CircleTM Microwave Ablation Therapy Planning System)which was designed by NanJing qiya machinery Co.Ltd. can help operators to simulate microwave in treatment of the malignant tumors in the computer during preoperation. Which provide a virtual environment to operators for observing and designing a customized operation. Resulting in ablating tumor completely and preventing normal tissue from damages. however. Correlation parameters in bone were not so clear. Objectives1. To investigate the ablated area and inactivated boundaries in bone with microwave-induced hyperthermia operation. Then to provide the foundation for simulated operations.2. To study the ablated ranges with microwave-induced hyperthermia operation through estabalishing simulated bone tumor model, which was verified by real one.Methods1. there were nine groups and seven bones in each group in the test. The rigid implanted microwave antenna with internally water-cooled were directly implanted into fresh porcine backbone and metaphyseal bone in vitro,working with different power and time.the first group is 60w/300s, the second group is 70w/300s, the third group is 80w/300s, the forth group is 90w/300s, the fifth group is 100w/300s, the sixth group is 100w/360s, the seventh group is 100w/480s, the eighth group is 100w/600s, the ninth group is 100w/720s.then we split bone in both transverse and longitudinal direction, observe gross changes of the bone,measure the long diameter and short diameter and observe morphology of the cancellous bone, cortical bone and normal bone of each other through TEM and light microscope.2. Normal porcine bone scanned by CT was imported into MWTps, then we build a test information and simulate a lesion range of 28×19×10mm,and regulate the ablation probe's location of the insertion site,the target point and the angle of needle. The volume of ablated area was generated through 60w/300s,70w/300s,80w/300s, 90w/300s,100w/300s,100w/360s,100w/480s,100w/600s,100w/720s.then we observed the ablation range and the level of security respectively and chose the best group. Then the bone were ablated according to technique parameters and splitted according to the direction of ablation needle. We chose the specimen related to ones in the simulation bone and observed through TEM. The difference of them was compared through statistics.Results1. The bone showed a constant lesion after implanted ablation. The shapes of ablation lesions were elliptical in the vertical plane while rotund in the horizontal plane. In the center of the ablated area was black zone:defining ablation zone,around the ablated area was gray zone, defining surrounding ablation zone, then we defined normal part as the far zone. the ablated area would be expanded with the increase of the power. While ablation in the cancellous bone,The volume of ablated area was 28×18×l5mm in the 60W300s, The volume of ablated area was 30x22×18mm in the 70W300s, The volume of ablated area was 33x26x29mm in the 80W300s, The volume of ablated area was 37x34x30mm in the 90W300s, The volume of ablated area was 41×36×32mm in the 100W300s, The volume of ablated area was 41 x29x26mm in the 100W360s, The volume of ablated area was 42x41 x38mm in the 100W480s, The volume of ablated area was 42x40x40mm in the 100W600s, The volume of ablated area was 42x42x40mm in the 100W720s.then ablation in the backbone.the volume of ablated area was limited with the limit of the diameter of the backbone,the long diameter expanded with increase of the power in the vertical split plane.which was 17mm generated by the 60w300s,19mm generated by the 70w300s,21mm generated by the 80w300s,22 generated by the 90w300s,24mm generated by the 100w300s,25mm generated by the 100w360s,26mm generated by the 100w480s,30mm generated by the 100w600s,30mm generated by the 100w720s.there are no difference among the ablation zone, surrounding ablation zone and far zone through the light microscope. However.the bone nuclei disappear in the ablation zone and surrounding ablation zone while normal bone cells and collagen remain in the far zone through the TEM.2. we simulate ablation in the range of lesion with 80w300s, the depth of needle was 29mm, insertion site was the lateral of femur,52mm from the cartilage surface of distal femur and 42mm from the ahead of the femoral condyle.and the angle of needle was 71.1°(the intersection angle between direction of ablation needle and sagittal line),and the lesion coverage was 100%,less damage to normal tissue.we could find 6 points in ablated ranges in simulated bone surgery. However, there were 5～8 bone specimens in ablated ranges.it was no statistical difference between simulated one and real one. Conclusions1. the ablation effects of implanted microwave on bone in vitro were very obvious.2. we explicit the site, depth, angle of ablation needle through simulating microwave ablation. Providing the foundation for inactivating bone tumor. |
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