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Objective:To investigate the value of preoperative MRI measurements of hamstring (semitendinosus+gracilis) tendon cross-sectional area in predicting intraoperative graft diameter for anterior cruciate ligament reconstruction (ACLR).Methods:A total of 265 preoperative MRI were retrospectively collected in the Third Affiliated Hospital of Southern Medical University from January 2013 to August 2020 for patients who underwent single-bundle ACLR of hamstring tendon. Patients were divided into a graft diameter≥8 mm group (129 patients) and a graft diameter<8 mm group (136 patients) according to intraoperative graft diameter. The cross-sectional areas of the semitendinosus and gracilis tendons were measured at the largest level of the femoral condyle on preoperative MRI cross-sectional images, and the two were summed to obtain the cross-sectional area of the hamstring tendon. The independent samples t-test was used to compare the differences in the cross-sectional area of each tendon between the graft diameter≥8 mm group and the graft diameter<8 mm group. The Spearman correlation analysis was used to assess the correlation between tendon cross-sectional area and intraoperative graft diameter. Multi-factor logistic regression analysis was used to screen the influence of tendon cross-sectional area on intraoperative graft diameter. The effectiveness of intraoperative graft diameter≥8 mm was assessed by plotting the receiver operating characteristic curves. Results:Intraoperative measurement of graft diameter was 7.5 (7.5, 8.0) mm. The cross-sectional area of the popliteal tendon was (21.4±4.6) mm 2 in the graft diameter≥8 mm group and (15.6±3.7) mm 2 in the graft diameter<8 mm group. Statistically significant differences were found in the cross-sectional areas of the semitendinosus, soleus and hamstring tendons between the graft diameter≥8 mm group and graft diameter<8 mm group ( t=-10.26, -10.29, -11.47, P<0.001). Intraoperative graft diameter was positively correlated with the cross-sectional area of the semitendinosus, gracilis, and hamstring, with correlation coefficients of 0.57 ( P<0.001), 0.58 ( P<0.001), and 0.62 ( P<0.001), respectively. Multi-factor logistic regression showed that popliteal tendon cross-sectional area was a predictor of intraoperative graft diameter (OR=1.45, 95%CI 1.32-1.59, P<0.001). The area under the curve for popliteal tendon cross-sectional area to predict intraoperative graft diameter≥8 mm was 0.838 (95%CI 0.792-0.885), with a critical value of 20.0 mm 2, a sensitivity of 0.581, and a specificity of 0.941. Conclusion:The measurement of the cross-sectional area of the hamstring muscle on preoperative MRI can predict the diameter of the autologous hamstring graft of ACLR.
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Objective To contrastively study the effects of NERC-300 high frequency welding device and ultrasonic scalpel in rat partial hepatectomy.Methods Forty-eight rats were divided into the experimental group and control group(n=24).The experimental group applied NERC-300 high frequency welding instrument for conducting partial hepatectomy,while the control group used ultrasonic scalpel.The survival rate,operation time,bleeding volume,working temperature,extent of hepatic thermal damage and change of liver function on 1,3,7 d were compared between the two groups.Results The liver function recovery on 3 d in the experimental group was superior to the control group (P＜0.05).The intra-operative working temperature in the experimental group was lower than that in the control group(P＜0.05).The thermal damage range in the experimental group was lower than that in the control group(P＜0.05).The survival rate,operation time,bleeding volume and liver function change on 1,7 d had no statistical differences between the two groups(P＞0.05).Conclusion NERC-300 high frequency welding device is safe and effective for partial hepatectomy in rat.