BACKGROUND: Magnalium which is potential to be the medical biodegraded metal implant is more and more interesting,but it must be well biocompatibility to human body.OBJECTIVE: To evaluate the sensitization of magnalium (AZ31B).METHODS: A total of 35 guinea pigs were randomly divided into saline group (negative control group,n=10),5% volume of formaldehyde (positive control group,n=10),and AZ31B group (n=15).Sensitization test at the maximal dosage was performed according to "Biological evaluation of medical devices-Part 10: Tests for irritation and delayed-type hypersensitivity",including intracutaneous induction,local induction,and provocation.Patch was removed after 6,24,48,and 72 hours,and the skin response was classified accordingto Magnusson and Kligman criteria.Patch was removed after 72 hours,and skin was performed with biopsy,stained with FIE staining,and observed under optic microscope.RESULTS AND CONCLUSION: Sensitization response was not tested in both negative control group and AZ31B group at 24,48,and 72 hours after patch removal; however,moderate erythema was observed in the positive control group.Optic microscope demonstrated that criteria of allergy such as spongiosis,edema,and diffuse as well as perivascular mononuclear infiltration was not observed in the AZ31B group,but a few basophilic calls ware observed.This suggested that AZ31B was biologically safe for sensitization.

Objective To evaluate the biomechanical characteristics and the clinical advantage of transoral atlantoaxial reduction plate(TARP)Ⅲ.Methods Design of TARP-Ⅲ was based on TARP-Ⅱ.The screw hole in the axis was moved 1-2 mm upwards and inwards in a plate which turned a vertebral screw into a pedicle screw or an articular process screw.A polyaxial self-lock ring and polyaxial guiding drill were added to the crew hole of the plate.Finally,the withdrawal resist ence force of the three axis screws was tested and TARP-Ⅲ was used in 44 patients with complicated irreducible atlantoaxial dislocation.The axis was fixed with the pedicle screw or the articular process screw.Results The maximum withdrawal resist ence force of the anterior pedicle screw,the articular process screw and the vertebral screw in the axis was(593.1 ± 97.8)N,(469.9 ± 73.3)N and(395.2 ± 75.1)N respectively,with statistical difference between groups among three fixation methods(P ＜ 0.05).All 44 patients were followed up for 5-38 months(average 18 months),which showed complete anatomic reduction in 36 patients and appropriate anatomic reduction in eight,with basic correction of the angles between the brain stem and the spinal cord and sufficient decompression of the spinal cord.The decompression rate of the cervical spinal cord was average 88.2% according to the Yin evaluating method of cervical cord decompression.The improvement rate of spinal cord function was average 76.6% according to Japanese Orthopaedic Association(JOA)score.Conclusion With the design of polyaxial self-lock mechanism,TARP-Ⅲ with the pedicle screw or the articular process screw surpasses TARP-Ⅱ with vertebral screw in aspect of biomechanics.

Objective:To evaluate the safety and efficacy of the treatment for oppressive spinal by microwave ablation combined with percutaneous fixation and open decompression.Methods:From January 2015 to September 2018, 20 patients with 26 spinal metastatic were treated with microwave ablation combined with percutaneous fixation and open decompression, including 13 males and 7 females with an average age of 43.85±18.67 years (range, 16-79 years). The locations of the lesions included: 9 in the thoracic, 11 in the lumbar. The tumors' type: myeloma 2 cases, leukemia 1 case, liver cancer 4 cases, osteosarcoma 2 cases, lung cancer 5 cases, kidney cancer 1 case, esophagus cancer 1case, cervical cancer 1 case, intestinal cancer 1 case, prostate cancer 1 case, adenoid cystic cancer 1case. Preoperatively all the patients suffered with the local pain and the spinal cord or nerve root compression symptoms. All 20 cases were examined with CT or MRI to determine the lesions and the sizes of metastasis, as well as to evaluate the ablation zone. The entry of the pedicle screws were performed by Wiltse method through paravertebral muscles. After that the lesions were treated with partial resection for decompression of spinal cord or nerve root, and followed with microwave ablation at the metastasis site. Thermometer was used to monitor the temperature at the central and posterior edges of the vertebral body. The surrounding important tissue were cooled by ice saline. 13 patients were performed with vertebroplasty for enhancement the intensity of the vertebral body. The visual analogue scale (VAS) score was used to evaluate the effect of pain relief after surgery. The postoperative neurological function and performance status were evaluated using Frankel grading and Eastern Cooperative Oncology Group (ECOG).Results:Each lesion was heated for 5.43±2.07 min (range, 3-10 min). The power of microwave ablation was 40-60 W. The mean blood loss during operation was 852.50±514.40 ml (range, 100-1 700 ml). The mean operating time was 4.11±0.99 h (range, 2.5-6.0 h). The temperature inside the lesion was 70-85 ℃. The temperature of the surrounding tissue was maintained at<43 ℃ by repeated frozen saline flush. All cases were followed up for 8.45±2.01 months (range, 6-14 months) without any recurrence. The VAS score of the 20 patients at 48 h, 1 month, 3 months and 6 months after operation were 1.55±1.23, 2.70±0.87, 2.40±1.14 and 3.05±1.00 points, which were all statistically lowerthan the preoperative score 5.95±1.18 ( P<0.05). The Frankel grading of 14 patients had at least one grade improvement 6 months after operation. There were 8 patients shown markedly improved ECOG score 6 months after surgery. Only one case suffered from reduced myodynamiaof lower limb and covered in one month after system treatment. Conclusion:The microwave ablation combined with percutaneous fixation and open decompression could resolve the spinal and nerve compression, relieve the pain in metastatic spinal oppression, reconstruct the stability, and improve the quality of lives, which is a safe and effective palliative surgical method.

【Objective】 To explore the clinical effects of autologous platelet-rich plasma (PRP) in the treatment of postoperative bone nonunion for long bone shaft fractures during operation and after operation. 【Methods】 A total of 34 patients with postoperative bone nonunion for long bone shaft fracture, who were admitted and cured in the Orthopedics Department of our hospital from January 2019 to June 2020, were selected. They were randomly divided into the experimental group(n=17) and control group(n=17). Individuals in the control were treated with autologous iliac bone alone., while the experimental group were treated with autologous iliac bone graft plus autologous PRP during and after operation. After surgery, the autogenous PRP was accurately injected with ultrasound guidance every 7 days (5 mL/person, 4 occasions in total). The clinical healing time of the fracture, the grading of callus formation and the functional rehabilitation level of limbs on the affected side at different time were observed in both groups. 【Results】 All 34 patients were followed up. In the experimental group and the control group, the clinical healing time (month) of the fracture was (5.03±1.24) vs (6.91±1.41), P<0.05. The healing rate of the fracture for 6 months and 9 months was 94%(16/17)vs 59%(10/17)and 94%(16/17)vs 82%(14/17), respectively (P<0.05). The grading of callus formation within 3, 6 and 9 months was (2.11±0.69) vs (1.53±0.80), (3.06±0.90) vs (2.59±0.87) and (3.82±0.73) vs (3.35±0.86), respectively (P<0.05). The acceptance rate of functional rehabilitation of limbs on the affected side was 82.35%(14/17)vs 76.47%(13/17), P<0.05. 【Conclusion】 The application of autologous PRP in the treatment of postoperative bone nonunion for long bone shaft fractures during operation and after operation can achieve good clinical treatment.