OBJECTIVE: To study the reparative and reconstructive methods for the large bone defect due to the excision of bone tumor. METHODS: According to the size and shape of the bone defect, we selected the proper bone and joint or manipulated bone segment of the profound hypothermia freezing allograft and gave locked intramedullary nails or steel plate and screws for stable internal fixation. RESULTS: In the 22 cases, 20 survived without tumor and 2 died. One patient treated with the allograft of semi-knee joint was found rejection. Then the wound did not heal. After the skin flap grafting was performed, the wound still did not heal, so the patient accepted amputation(4.5%). In the other 21 cases, the X-ray and 99mTc SPECT showed some callus or concentration of nuclein which implied bone union. According to Markin bone graft criterion, the excellent rate of function recovery was 81.8%. CONCLUSION: Allografting of bone and joint is a good and workable method in repairing and reconstructing the bone defect due to the excision of bone tumor. It should be further studied and be applied.
Objective To evaluate the shortterm efficacy of osteoarticular allografts in the limb salvage of the proximal tibia. Methods From 1998 to 2003, 15 patients (7 males, 8 females; aged 14-56 yr, average 33) with bone tumor of the proximal tibia underwent osteoarticular allografts, among whom 7 had progressive giant cell tumor without any previous chemotherapy; 8 had malignant tumor with previous chemotherapy, including 6 patients with osteosarocoma, 1 with spindle cell sarcoma, and 1 with malignant fibrous histiocytoma. According to the Enneking system, the patients were classified into ⅠB (7 patients), ⅡA (2 patients), and ⅡB (6 patients). All the patientsunderwent the marginal resection with an allograft (average length 12 cm, range6-16 cm) implanted. Results The follow-up for an average of 21 months (range,3-58 months) revealed that among the 8 patients with malignant tumor of the proximal tibia undergoing chemotherapy, 5 had union of the bone, 3 had no union of the bone; among the 3 patients, 2 had a complication of infection and 1 had a local recurrence. All the 3 patients underwent amputation at the lower part of the femur. According to the Mankin score, 2 patients had a perfect result, 2 good, 1 fair, and 3 poor, with a 50% effectiveness rate. Among the 7 patients with progressive giant cell tumor at the upper part of the tibia, none had infection or local recurrence, but 2 hadnonunion of the bone and 2 had joint instability, aided by the kneeaidingsystem. According to the Mankin score, 3 patients had a perfect result, 2 good,and 2 fair, with a 71% effectiveness rate. Conclusion The osteoarticular allograft of the proximal tibia has many advantages in spite of a relatively highrate of complications, and it is the limb salvage of choicefor the progressivebenign or malignant bone tumors of the proximal tibia.
Objective To study the effect of vascular endothelial cell growth factor (VEGF) on repair of bone defect with cortical bone allograft. Methods Forty five New Zealand white rabbits, weighted 2.5-3.0 kg, were made bone defect model of 1.5 cm in length in the bilateral radii and then were randomly divided into 3groups. The defect was repaired with only cortical bone allograft in the control group, with the cortical bone allograft and local injection of human recombinantVEGF in the experimental group, and with the cortical bone allograft and abdominal injection of VEGF PAb3 in the antagonist group. Roentgenography, immunohistochemical staining and tetracycline labelling were carried out to evaluate the reparative results 1, 3, 5, 8 and 16 weeks after operation. Results Immunohistochemical staining results showed that a great deal of blood vessels formed in the experimental group, and the number of blood vessels increased gradually with the time and reached the highest value at the 8th week. Tetracyclinelabelling showed the same result.The best results in callus formation, ossification rate and count of microvascular density were shown in the experimental group, while those in the control group were significantly better than those in the antagonist group (Plt;0.05),but there was no significant difference between the experimental group and the control group at the 8th week and the 16th week (Pgt;0.05). Conclusion VEGF can accelerates the bone formation and angiogenesis in the bone allografts, thus it can promote the repair of bone defects.
OBJECTIVE: To evaluate the results of limb function and the methods of bone and soft tissue reconstruction of patients treated with allografting. METHODS: From May 1992 to January 1999, 90 patients suffered from bone malignant tumor were treated with allografting in different methods of internal fixations. The average follow-up was 37.5 months. The limb postoperative function, complications related to different surgical methods were compared according to Enneking evaluation system. RESULTS: Skin necrosis, infection, non-union, fracture of allograft were the main complications which affect patients’ limb postoperative functions. Of the 90 fresh-frozen allografting procedures, the final results of operation showed that hip joints and knee joints were better than the shoulder joints. More than 80% of the patients treated with interlocked intramedullary nail and allograft-prosthesis combination led to an over-all result that was excellent and good. Interlocked intermedullary nail was of recommended method of internal fixation. Early exercises of operative limbs could promote function recovery. CONCLUSION: Using of interlocked intramedullary nail and allograft-prosthesis combination are of recommended operation method and can be applied with better results, and early exercises of operative limbs will lead to better functions.
Objective To explore the biomechanical difference between the different fixations of cortical bone plate allograft. Methods Twenty-seven cadaveric femurs were harvested and were made into the simulated fracture models, which were equally divided into Groups A, B and C. In Group A, the models were fixed with 2 bone plate allografts (110 mm×10 mm×3 mm); in Group B, the models were fixed with 2 struts (110 mm×10 mm×3 mm) and 5 bone screws; in Group C, the models were fixed with 1 strut (110 mm×10 mm×3 mm) and 5 bone screws. The biomechanical tests for the three-piont bending, torsion, and compression were performed. The parameters studied included the values of the displacements in the three-piont bending tests and the compression tests, and the maximum loads during the bending, the compression, and the torsion. Results As for all the stiffness parameters tested, Group A showed the greatest displacements among the threegroups（P＜0.05）, except the compressive stiffness parameter, which was similar to that in Group B. The maximum loads of the three-point bending, the torsion, and the compression in Group A were 1.65±0.34 kN, 554.3±49.34 N, and 7.78±0.82 Nm, respectively; in Group B, they were 1.12±0.37 kN, 428.00±37.40 N,and 3.39±0.22 Nm, respectively; in Group C, they were 0.71±0.46 kN, 218.67±36.53N, and 1.74±0.12 Nm, respectively. Group A had a significantly greater strengththan the other 2 groups(P＜0.05). Conclusion The strength of the cortical bone plate allograft is related to its different fixations. The two cortical bone plate allografts have a greater strength and stiffness than the struts fixed with the bone screws, which can meet the clinical requirement.
Abstract: Objective To investigate the influence of cryopreservation on cellular viability of latepregnancy fetal valved allografts in human. Methods The fetal valved allografts with gestational ages ranged from 24 to 40 weeks were sterilely procured within 6 hours after brain death. Each sample was bisected into control group and experiment group. The cellular viability of control group was directly tested and that of experiment group was examined after being storaged in liquid nitrogen for a week through a programmed frozen procedure. The light microscopy, tissue culture and Methylthiazol tetrazolium assay (MTT assay) were used to determine the cellular viability. Results Twelve latepregnancy fetal valved aortic allografts were procured. Light microscopy showed the integrity of the basic structure of the thawed aorta, the normal structure of the collagen and elastic fibers, with part of vascular endothelium lost. There were lots of cells deriving from both groups,but the cellular growing rate of the experiment group was relatively slower. At 490 nm, MTT assay valve of control group was 0.442±0.046, and that of experiment group was 0.424±0.041. The difference between two groups failed to statistically significance(t=1.617, P=0.328). Conclusion There were viable cells in latepregnancy fetal valved allografts after cryopreservation.
OBJECTIVE: To evaluate clinical outcome of bone or osteoarticular allografts. METHODS: From September 1991 to November 1997, large bone or osteoarticular defects secondary to bone tumors resection in 36 patients and severe trauma in 2 patients were repaired by deep frozen or lyophilized allogeneic osteoarticular or diaphysis graft. RESULTS: No obvious immune rejection to the grafts was observed in most of the patients in early stage after operation. The patients were followed up from 1 year and five months to 7 years and five months with an average of 4.2 years. Limb function was satisfactory in 74.19% of the 31 survival patients with large osteoarticular or diaphysis allografts. CONCLUSION: Cryopreserved or lyophilized allogeneic osteoarticular grafts with decreased antigenicity and good biocompatibility are suitable materials for repairing large bone or osteoarticular defects.
Objective To study the migration of Schwann cells from the nerve autograft in the acellular nerve allograft of the rats in vivo. Mehtods The sciatic nerves (20 mm long) of the SD rats were harvested and prepared for the acellular nerve grafts by the chemical extraction. Then, they were observed by the gross view, HE staining, and Antilamininstaining, respectively. Another 32 female SD rats weighing 250-300 g were obtained for the study. A 2-mm-long nerve autograft was interposed between the two 10-mm-long nerve allografts to form a 22-mm-long composite. Then, the composite was placed in the muscle space, together with a sole 22-mm-long nerve allograftas a control. They were harvested at 5，10，15 and 20 days, respectively, and were then given the HE staining and the S-100 staining. Results The acellular nerve graft was semitransparent under the gross view. HE staining showed that no cell was observed within the nerve graft. Anti-laminin staining showed that the basal membrane was partially interrupted, with a positive result (dark brown). All the nerve grafts in both the groups exhibited the existenceof the cells. The S-100 positive cells were observed from the 15th day at the far ends of the two allografts of the composite; however, there were no suchcells observed within the sole nerve allograft. Conclusion Schwann cells from the sciatic nerves (2 mm- long) of the rats can migrate in the acellular nerve allograft to the far ends of the neighboring 10-mm-long nerve allografts at 15 days after operation, which offers the theoretical basis forthe repair of the longrange nerve defect by the composite of the acellular nerve allografts with the interposed nerve autograft.
ObjectiveTo investigate the short-term effectiveness of percutaneous pedicle fixation combined with intravertebral allograft by different methods for thoracolumbar fractures. MethodsThe clinical data of 94 patients with single segment thoracolumbar fracture who underwent percutaneous pedicle fixation combined with intravertebral allograft by different methods between October 2018 and October 2019 were retrospectively analyzed. According to the different methods of intravertebral allograft, they were divided into group A (bone grafting by Jack dilator, 40 cases) and group B (bone grafting by funnel, 54 cases). There was no significant difference between the two groups (P>0.05) in the gender, age, body mass index, cause of injury, injured segment, Wolter index, time from injury to operation, and preoperative visual analogue scale (VAS) score, injured vertebral height ratio, and Cobb angle. The operation time, fluoroscopy frequency, allograft volume, and complications were recorded and compared between the two groups. VAS score of low back pain was used to evaluate the remission of clinical symptoms before operation, at 3 days, 3 months, 12 months after operation, and at last follow-up. The injured vertebral height ratio and Cobb angle were measured before operation, at 3 days, 3 months, and 12 months after operation. ResultsThe operation time, fluoroscopy frequency, and allograft volume in group A were significantly higher than those in group B (P<0.05). No complication occurred after operation, such as loosening or fracture of internal fixation. And bone grafting in the injured vertebrae healed at last follow-up. The VAS score, injured vertebral height ratio, and Cobb angle at each postoperative time point significantly improved when compared with preoperative ones (P<0.05); compared with 3 days postoperatively, the VAS score improved further after 3 months, but the injured vertebral height ratio decreased and the Cobb angle increased, and the differences were significant (P<0.05). There was no significant difference in the VAS scores of low back pain between the two groups at each time point after operation (P>0.05); the injured vertebrae height ratio in group A was significantly higher than that in group B, and the Cobb angle was significantly lower than that in group B, all showing significant differences (P<0.05). ConclusionThe intravertebral allograft via Jack dilator can restore the height and decrease the Cobb angle of the injured vertebrae, but accompanied with higher fluoroscopy frequency and longer operation time when compared with funnel bone grafting. For patients with single level thoracolumbar fractures, intravertebral allograft via Jack dilator is recommended.
Objective To investigate the research advance in repair of the peripheral nerve defect with an acellular nerve allograft. Methods The recent related literature was extensively and comprehensively reviewed. The methods and the effects of the allografts with acellular nerves were analyzed. Results The immunogenicity of the allograft was more significantly relieved by the chemical treatment than by the physicaltreatment. The effect of the chemical treatment on the axon regeneration was better than that of the physical treatment. Conclusion Because of the limitation of the host Schwann cell translation in the longsegment acellular nerve allografts, the effect of Schwann cells is not satisfactory and regeneration of the nerve is limited. So, the recellularized treatment with some related measures can enhance the host Schwann cell translation so that this problem can be solved.