| Objective Limb salvage surgery is one of the most regular surgical treatment of bonetumor, and bone allograft transplantation is also commonly used in biologicalreconstruction after en bloc resection. However, the variation of different shapes of boneallografts and the mismatch to the defects usually bring adverse effects on the long-termresults of reconstruction after bone tumor resection. The critical part of this problem is thatallograft bone is hardly to be choosed quickly and accurately. The aim of this stuty is toexplore the feasibility of establishing the digital bone bank, and to observe the effects ofthe digital bone bank on preoperative design of bone tumor resection, matching andtailoring of bone allograft, and accurate reconstruction of bone defect. The criticalproblem of the precision with the application of computer-assisted navigation techniqueon bone tumor resection and the accuracy of bone allograft in biological reconstructionmay be solved by this technique. Clinical treatment outcome will be evaluated to investigate the feasibilityand the effectiveness of the digital bone bank.Methods1. The procedure of establishment and application of the digital bone bank: thecryopreserved allograft bones in the comprehensive bone bank of the Fourth MilitaryMedical University Xijing Hospital were scanned by using64slice spiral CT scanner.Then the digital analysis management system of the allografts(digital bone bank) wasestablished by3D reconstruction. With the assistance of the digital bone bank, the bestmatching allograft could be rapidly and accurately selected, and the designed tumorresection zone and the resecting margins could be showed and marked precisely. Aftermeasuring the bone defect size and selecting the matching bone allograft in the digitalbone bank, the resection and reconstructing could be simulate by the computer.2.Thecriteria of the case collection and selection:(1) the presence of indications of allograftlimb salvage surgery; tumor growth in the bone or surround the bone; the relative tumorposition will note be changed preoperation and intra-operation; obvious bone landmarksaround the tumor; and the need of precise osteotomy around the tumor.(2)The criteria ofexclusion: The tracer could not be stably fixed around the incision or the tumor; the tumorcould only be partly curetted; and soft tissue tumors. FromJanuary2011to January2014,29cases of primary periarticular bone tumor were included in the orthopedic oncologydepartment of Xijing Hospital, including19cases of male,10female, with an average ageof22.7years. Pathological types:20cases of osteosarcoma in which juxta-corticalosteosarcoma in7cases,4cases of Ewing’s sarcoma,1case of chondrosarcoma,4casesof bone giant cell tumor. Location of the tumor:1case in scapula,1case in clavicle,3cases in pelvis,1case in proximal humerus,1case indistal humerus,2cases in distalradius,2cases in femoral shaft,6cases in the distal femur,10cases in proximal tibia, and2cases in distal tibia. Except for4cases of Ewing’s sarcoma, according to Ennekingstaging,25cases of primary bone tumors included:4cases of benign bone tumors (stage3,stage of invasion),21cases of malignant bone tumors (7cases in IB stage,2cases in stageⅡA,12cases inⅡB). All the patients had no contraindications of limb salvage operation.Preoperative biopsy was performed on all the patients in order to identify pathologicdiagnosis and to determine operation schedule. Except for cases of chondrosarcoma, other cases of malignant bone tumors (20cases of osteosarcoma and4cases of Ewing’ssarcoma)all received standard neoadjuvant chemotherapy and adjuvant chemotherapy aftersurgery.3. Precise bone tumor resection and accurate reconstruction of bone allograft bycomputer-assisted navigation: The data were imported into computer navigation system(Cart Ⅱ Navigation System, Stryker, USA). Based on the preoperative design, theoperation and monitoring were performed under navigation. This group of patients weretreated using the digital bone bank combined with computer-assisted navigationtechnology. The operations were performed according to the originally designed schedule,and the patients underwent regular follow-up postoperatively. With the function score ofMusculoskeletal Tumor Society (MSTS), the postoperative functional situation and theoncologic results were evaluated.Results The critical technologic problem of the accurate allogenicbone reconstruction ofbone defects after bone tumor resection had been solved in our study.29patients weretreated successfully by using digital bone bank combined with computer-aided navigation.With the establishment of the digital bone bank, the mean matching time was reduced to5minutes from1hour, and the percentage of matching accuracy was improved to95%from30%comparing with conventional preoperative preparation of bone allograft. At the sametime, the resection margin can be accurately programmed with the CT-MRI3D imagefusion technique before surgery. En bloc tumor resection, bone allograft incision and jointforce line monitoring during operation can be performed with the computer-assistednavigation. The anatomical registration points and CT3D virtual image were preciselymatched, with a registration error0.47±0.19mm. There was no vascular and nervedamage in the surgery, and the pathological examination of tumor specimens showed notumor cells left at the incision margins. Postoperative imaging showed that the en bloctumor resection zone and allograft incision area completely coincided with thepreoperative plan, and showed stable joint reconstruction without limb length discrepancyand joint deformity. The average follow-up of this study was20.8months. One case withright clavicle osteosarcoma had local recurrence18months after the surgery, and then theextended resection exclusion surgery and the assisted second-line chemotherapy were performed. One case with right proximal tibial osteosarcoma9months after surgery, onecase with left proximal tibial osteosarcoma6months after surgery, and one case with rightfemoral osteosarcoma15months after surgery had lung metastases. They receivedradiotherapy of the lung lesions and second-line chemotherapy. All4patients were stillalive, and there was no deaths in the whole group. During the follow-up, there were noobvious immune rejection, and the average healing time of allograft and host bone was6.1±2.5months. The severe complications did not appear, such as nonunion, allograftfracture, loosening and rupture of internal fixation, or joint collapse. MSTS93functionscore was25.1±3.2in average.Conclusion The establishment of the digital bone bank provides reliable, visual, fastinformation for preoperative selection of allogenic bone. On the basis of acquiringtumor-free resection margins, the precise resection, accurate match and meticulousoperation and the surgeon were closely associated. Comparing with the previous empiricaloperation mode, the rational use of digital bone bank information combining with theoperation design, implementation and evaluation by navigation system, is feasible andeffective in the entire treatment process. This can give the patient a delicate biologicalreconstruction surgery, and can further improve the safety and effectiveness of the limbsalvage. Our team gained abundant experience in the applications of digital bone bank andcomputer-assisted navigation. The accuracy, personality, and fineness of biologicalreconstruction after bone tumor resection using bone allograft can be realized through theuse of digital bone bank. Good limb function recovery, low incidence of complicationsand satisfied short term follow-up results can be observed after surgery. The long-termresults still need further observation. |
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