A novel testing system is designed to simulate the mechanical performance and evaluate the biomechanical properties of the bone and the corresponding bone fixator. It is mainly composed of movement platform and servo motor system, sensors and hardware circuit system and software system. In order to prove the feasibility of the design, on the basis of the calibration for the force sensor, the fatigue experiment is carried out using the tibia of the sheep. It is concluded from the result that under the condition of 1 Hz in frequency, 50 kg in loading force and 18 000 cycles, the bone fixator can be still in good condition, which proves the feasibility of the design.
Animals ; Biomechanical Phenomena ; Bone Screws ; Mechanical Phenomena ; Sheep ; Stress, Mechanical ; Tibia ; physiology

Objective To investigate the efficacy of external pelvic reduction frame system combined with tunnel screw fixation in the treatment of Tile C1 pelvic fracture.Methods A retrospective case series analysis of 15 patients with Tile C1 pelvic fractures from January 2014 to October 2016 was pedormed.Clinical data included seven males and eight females,aged 26-84 years (mean,48.9 years).According to Tile classification,there were five cases of type C1.1,three cases of C1.2,and seven cases of type C1.3.The average time from injury to surgery was 9.5 days (range,4-33 days).All patients received the treatment of external pelvic reduction frame system combined with tunnel screw fixation.The operation time,intraoperative blood loss,and complications were recorded.The fracture reduction quality was evaluated according to the Matta criteria,and the clinical function and neurological function were evaluated by the Majeed functional scoring system and the Gibbons sacral nerve injury grading,respectively.Results The patients were followed up for an average of 16 months (range,12-24 months).The mean operation time was 139 minutes (range,50-250 minutes),and the mean intraoperative blood loss was 90 ml (range,20-260 ml).No complications such as wound infection,loose internal fixation,rupture or loss of reduction occurred in the patients.According to the Matta score,14 patients obtained anatomical reduction,and one obtained satisfactory reduction.At the last follow-up,according to the Majeed functional scoring criteria,the results were excellent in all 15 patients,with an excellent and good rate of 100％.According to Gibbons sacral nerve injury grading,two out of the three patients with neurologic impairment before the operation recovered completely while the remaining one did not recover.Conclusion In the treatment of Tile C 1 pelvic fractures,external pelvic frame reduction system combined with tunnel screw fixation can attain satisfactory fracture reduction,reliable fixation,and good functional recovery.

Objective To treat calcaneal fracture with plate fixation combined with 64-slice CT 3D reconstruction and to analyze the efficacy.Methods Totally 86 patients with Sanders Ⅲ and Ⅳ types of calcaneal fractures underwent surgical treatment,and 64-slice CT 3D reconstruction was used to record the length,height,width,Bohler angle and Gissane angle of calcaneus before and 1 d,2 d,3 d and 1 a after the treatment.Postoperative evaluation was executed based on AOFAS Ankle Hindfoot Scale.Results All the fractures healed,of which,there were 60 ones scored as excellence,19 ones in good condition and 7 ones in satisfactory condition with the excellence and goodness rate being 91.9％.Complications occurred in 4 patients,with 3 cases of delayed healing and one case of infection.Tbere were obviously differences between the lengths,heights,widths,Bohler angles and Gissane angles before and after the treatment,while the differences were not significant between the measured values 1 d and 1 a after the treatment.Conclusion 64-slice CT 3D reconstruction is an excellent clinical auxiliary tool,and is of great value for fracture typing,operational plan preparation,postoperative evaluation and late efficacy assessment.

The vascular mechanical parameters are important indicators for human vascular and they play important roles in clinical research. This paper developed a new vascular mechanical properties testing system. This system not only realizes the tensile rupture test in one dimensional, but also the reciprocating tensile test for vascular, which provides more comprehensive experimental data and theoretical basis for the study of human vascular. The system consists of three parts: the mechanical platform, hardware circuit and upper computer system. The mechanical platform transforms the rotation movement of motor into linear movement via the structure of bal screw. And the bal screw and tension sensor are connected, which is used for mechanical data reading. The displacement data is col ected by displacement sensor. Experiments show that the accuracy is better than 0.292%, and could meet the demand of the testing of vascular biomechanical characteristics.

Complex and huge wound closure is a key step in pre hospital emergency care. Wound closure can effectively reduce the loss of blood and fluid inpatients before arriving hospital. Also, it has important significance to save the lives of patients. In this paper, a new type of wound closure device is developed, which is used for the rapid closure of complex and huge wound. Firstly, based on the detailed introduction of the structure working principle, the finite element simulation technology is adopted to analyze the stress of the structure. The results show that the stress of the structure has not beyond the allowable stress of the material. On the basis of this, the experiment was carried out in vitro. Test results show that the closure device operating time is 18.24 s and the minimum penetration of the skin force is 4.08 kg. The closure device can resist the horizontal tension of 1.53 kg and vertical tension of 2.25 kg. It also has good sealing performance and meets the design requirements. The results show that the device designed is reasonable, which can be quickly and effectively to achieve closure of the wound.

In the background of the high incidence of vascular injury in wartime,this paper introduces the characteristics of vascular injury in war environment and the development of early treatment technique of vascular injury applied in wars since World War Ⅱ. Then,the advantages and limitations of various treatment techniques are also analyzed. Finally,The development of technology and research direction are summarized and prospected.

Objective To evaluate the curative effects of percutaneous osteoperiosteal decortication combined with distraction osteogenesis for treatment of nonunion of lower-extremity bones.Methods A retrospective analysis was performed of the 32 patients who had been treated using osteoperiosteal decortication combined with distraction osteogenesis from September 2011 to December 2014 for nonunion of lower-extremity fractures.They were 23 males and 9 females,with a mean age of 33.4 years (range,from 15 to 62 years).After their former internal or external fixators were removed,the 2 fracture ends were fixated by a retractile mono-lateral or circular external fixator.Under radiographic monitoring,a percutaneous incision was made with a 5 mm sharp chisel,down to the bone.Scar and ossified tissue between the fracture ends were debrided and cut along the fracture line.Mter the marrow cavity was reamed,a new irregular wound was created at sclerotic fracture ends.Scale-shaped chips (1 mm thin and 5 mm in diameter) were elevated using a chisel on surface of the cortical bone within 2 cm from the fracture ends.The external fixators were adjusted to compress the fracture sites.On the 8th day after operation,the eternal fixators were applied to distract and compress at nonunion sites to stimulate the osteogenesis.Results All the patients were followed up for an average of 12.5 months (range,from 8 to 42 months).Primary union was successfully achieved in 28 patients while delayed union occurred in 3 patients who finally achieved union after adjuvant therapies like shock wave and or local injection of bone marrow blood.The average time for union was 4.6 months(range,from 4 to 7 months).The mean time for external fixation was 6.2 months (range,from 5 to 8 months).One patient encountered nonunion of lateral tibial cortical bone 6 months after surgery but eventually achieved union by autologous ilium grafting.Joint functions in all postoperative patients were similar to those before operation.Conclusion Percutaneous osteoperiosteal decortication combined with distraction osteogenesis is a simple,minimally invasive and effective treatment for nonunion of lower-extremity bones,avoiding disadvantages brought by traditional surgery,like massive trauma and excessive bleeding.

Objective To perform modification study of cyanoacrylate (CA) medical adhesive and to select the optimal mo-difying material and the best ratio.Methods Carboxylic multi-walled carbon nanotubes (MWCNTs-COOH), multi-walled carbon nanotubes (MWCNTs), hydrophobic nano-silica, nitrile rubber, epoxy resin and polymethyl methacrylate (PMMA) were used to modify 5% triclosan/cyanoacrylate antimicrobial adhesive respectively. The bond strength, toughness and viscosity of the modified adhesive were examined in different concentrations.Results 0.064% MWCNTs-COOH, 6% nano-silica, 4% nitrile rubber and 6.4% epoxy resin all had good effects in strength modification. The bond strength were (14.71±1.48)MPa, (14.03±1.92)MPa, (14.6±1.78)MPa and (14.05±1.46)MPa respectively. 8% nano-silica had the lowest Tg of (1.1±0.24)℃ and the strongest viscosity of (15 536.68±28.4)cP. When the nano-silica concentration was 8%, the compound was very viscous and sticky. When the antimicrobial adhesive modified with 6% nano-silica, the bond strength was (14.03±1.92)MPa, the Tg was (3.6±0.68)℃, and the viscosity was (5 278.87±31.68)cP.Conclusion 6% nano-silica is the best modifying material, and has the optimal effect of modification.

BACKGROUNDSelf and mutual-aiding occlusive dressing is a novel method to treat with the wounds in special circumstances. This study aims to prepare a new antimicrobial adhesive for the dressing and evaluate the application effects of the adhesive.

METHODSThe main component of the new antimicrobial adhesive was 5% triclosan / cyanoacrylate (CA) antimicrobial adhesive. The adhesive was modified with carboxylic multi-walled carbon nanotubes (MWCNTs-COOH), multi-walled carbon nanotubes (MWCNTs), hydrophobic nano-silica, nitrile rubber, epoxy resin and polymethyl methacrylate (PMMA) respectively. The bond strength, toughness and viscosity of the modified adhesive in different concentrations were examined to select the optimal modifying material and the best ratio to prepare the new antimicrobial adhesive according to the results. After that, the antimicrobial property of the new antimicrobial adhesive was tested by filter paper method. At last, we disposed the injury models in rats using the new antimicrobial adhesive to examine the application effects.

RESULTSIn individual tests, the bond strength modification performance of 0.064% MWCNTS-COOH is the best, the bond strength is (14.71 ± 1.48) Mpa. 8% nano-silica shows the best toughness modification performance, the Tg is (1.10 ± 0.24)°C. The viscosity modification performance of 8% nano-silica is the best, the viscosity is (15 536.68 ± 28.4) cP. However, consolidating three test results, 6% nano-silica/antimicrobial adhesive has the balanced bond strength, toughness and viscosity. Its bond strength is (14.03±1.92) Mpa, the Tg is (3.60 ± 0.68)°C, and the viscosity is (5 278.87 ± 31.68) cP. The inhibition zone diameter of 6% nano-silica/antimicrobial adhesive and antimicrobial adhesive group in Day 5 is (28.61 ± 0.91) mm versus (28.24 ± 2.69) mm (P > 0.05). In animal studies, both in blood routine test and pathological section, 6% nano-silica/antimicrobial adhesive group shows lower white blood cells count than gauze bandage group (P < 0.05).

CONCLUSIONS6% nano-silica has the optimal effect of bond strength modification, toughness modification and viscosity modification, and the antimicrobial adhesive modified with it has a good antimicrobial property (resistant staphylococcus aureus).

Animals ; Anti-Bacterial Agents ; chemistry ; therapeutic use ; Cyanoacrylates ; chemistry ; therapeutic use ; Male ; Nanostructures ; chemistry ; therapeutic use ; Occlusive Dressings ; Rats ; Rats, Sprague-Dawley ; Triclosan ; chemistry ; therapeutic use

BACKGROUNDCurrently, adhesive technique is popular in vascular repair but not widely used for defective vessels. This study aimed to determine the feasibility and effectiveness of repairing defective vessels with 2-octyl-cyanoacrylate and a homemade prosthetic component.

METHODSHomemade prosthetic component consisting of expanded polytetrofluoroethylene (ePTFE), terylene film, and homemade soluble hollow stent mixed with adhesive can replace autologous graft and suture in repairing defective vessels, can fix vessels better using the stent without occlusive bleeding. Forty male mongrel dogs were used, 20 for biomechanical tests and 20 for animal experiments. In the biomechanical test, dogs were randomly divided into two groups (n = 10 each), one group repaired on the two sides of the carotid arteries with 2-octyl-cyanoacrylate and homemade component and another group repaired with suture and ePTFE. Of the 40 specimens, 10 were used for adhesive and 10 for suture specimens for tension strength test, whereas the remaining specimens were used for bursting pressure test. In animal experiments, dogs were also divided into adhesive and suture groups (n = 10), only of the left carotid artery. Recording the operational time, bleeding or not. Vessels were tested using color Doppler ultrasound, the inner diameter was measured, and the degree of stenosis at 8 weeks was evaluated digital subtraction angiography (DSA) were also performed. Specimens were then analyzed histologically.

RESULTSIn the adhesive and suture groups, the specimens could afford atension strength of (23.80 ± 1.51) N versus (24.60 ± 1.08) N (P > 0.05), the bursting pressure was (52.03 ± 2.43) kPa versus (50.04 ± 3.51) kPa (P > 0.05), and the mean time of anastomosis was (15.20 ± 0.55) minutes versus (25.97 ± 0.58) minutes (P < 0.05). One dog in the adhesive group was bleeding from the suture. One dog from each group presented with thrombosis at 1 week. After measuring using ultrasound, the stenosis degree of all dogs were no more than 30% except the two thromboses. DSA and histological observation showed no obvious difference between the two groups.

CONCLUSIONDefective vascular anastomosis with 2-octyl-cyanoacrylate and our homemade prosthetic component is feasible, effective, timesaving, and easy to master.

Anastomosis, Surgical ; methods ; Animals ; Carotid Arteries ; surgery ; Cyanoacrylates ; therapeutic use ; Dogs ; Male ; Reconstructive Surgical Procedures ; methods ; Vascular Surgical Procedures ; methods