Objective:To study a new positioning method of elbow external fixation rotation axis,and to evaluate its feasibility.Methods:Four normal adult volunteers and six Sawbone elbow models were brought into this experiment.The kinematic data of five elbow flexion were collected respectively by opti-cal positioning system.The rotation axes of the elbow joints were fitted by the least square method.The kinematic data and fitting results were visually displayed.According to the fitting results,the average moving planes and rotation axes were calculated.Thus,the rotation axes of new kinematic methods were obtained .By using standard clinical methods,the entrance and exit points of rotation axes of six Sawbone elbow models were located under X-ray.And The kirschner wires were placed as the representatives of rotation axes using traditional positioning methods.Then,the entrance point deviation,the exit point de-viation and the angle deviation of two kinds of located rotation axes were compared.Results:As to the four volunteers,the indicators represented circular degree and coplanarity of elbow flexion movement tra-jectory of each volunteer were both about 1 mm.All the distance deviations of the moving axes to the ave-rage moving rotation axes of the five volunteers were less than 3 mm.All the angle deviations of the mo-ving axes to the average moving rotation axes of the five volunteers were less than 5 °.As to the six Saw-bone models,the average entrance point deviations,the average exit point deviations and the average angle deviations of two different rotation axes determined by two kinds of located methods were respective-ly 1.697 2 mm,1.838 3 mm and 1.321 7°.All the deviations were very small.They were all in an ac-cep-table range of clinical practice.Conclusion:The values that represent circular degree and coplanari-ty of volunteer's elbow single curvature movement trajectory are very small.The result shows that the elbow single curvature movement can be regarded as the approximate fixed axis movement.The new method can replace the traditional method in accuracy.It can make up the deficiency of the traditional fixed axis method.

Objective:To compare two different methods for the harvest of the costal cartilage cortical slice with perichondrium preserved for rhinoplasty patients, and to explore a simple and less invasive method for the costal cartilage cortical slice.Methods:From September 2019 to December 2020, the rhinoplasty patients using the techniques of nasal tip "double arch" stent combined with prosthesis were selected in Shanghai Time Plastic Surgery Hospital, they were randomly divided into observation group and control group. In the observation group, only the cortical slice of costal cartilage with perichondrium was cut and the continuity of costal cartilage was preserved. While in the control group, with the superficial perichondrium preserved, the whole costal cartilage was dissected first, and then pruned it and harvested the cortical slice of costal cartilage with perichondrium. The operation were performed by the same clinicians in both groups. Different variables were compared between the two groups, including the operation time, intraoperative blood loss, length of incision, the degree of chest pain after postoperative 6, 24, 72 h, 1 week, the incidence of intraoperative complications and so on. The severity of chest pain was assessed by visual analogue scale (VAS). The measurement data of the two groups were analyzed by t-test, and the enumeration data were analyzed by χ2 test. Results:For both observation group and the control group, 61 patients were included. In the observation group, there were 3 males (4.9%) and 58 females (95.1%), aged (28.6±5.4) years old, and BMI (21.76±1.65) kg/m 2. In the control group, there were 2 males (3.3%) and 59 females (96.7%), aged (45.8±5.7) years old, and BMI (22.25±1.47) kg/m 2. There were no significant differences in gender composition, age and BMI between the two groups ( P>0.05). The double arch stent of nasal tip could be made by the costal cartilage cortical slices obtained in the two groups. In the control group, two cases of pleural rupture occurred and their prognosis was good after effective treatment, with no complications such as hematoma, infection or pleural injury. In the observation group, there were no complications such as hematoma, infection or pleural injury. The operation time, incision length and intraoperative blood loss in the observation group were significantly lower than those in the control group [(18.54±3.62) min vs. (25.75±3.75) min; (1.68±0.26) cm vs. (2.16±0.32) cm; (16.79±7.86) ml vs. (25.46±8.49) ml; P<0.05]. The VAS score in the observation group was lower than that in the control group after postoperative 6, 24, 72 h, 1 week [(2.76±0.62) vs. (3.87±0.68)scores; (2.37±0.45) vs. (3.12±0.55) scores; (1.76±0.45) vs. (2.57±0.53) scores; (1.17±0.44) vs. (1.85±0.51) scores; P<0.05]. Conclusions:Compared with the conventional method of whole costal cartilage harvest, the method of harvesting the costal cartilaginous cortical slice with the costal perichondrium preserved and preserving the continuity of the costal cartilage can reduce the trauma and bleeding, shorten the operation time, simplify the operation process, and significantly reduce the postoperative chest pain.

Objective:To compare two different methods for the harvest of the costal cartilage cortical slice with perichondrium preserved for rhinoplasty patients, and to explore a simple and less invasive method for the costal cartilage cortical slice.Methods:From September 2019 to December 2020, the rhinoplasty patients using the techniques of nasal tip "double arch" stent combined with prosthesis were selected in Shanghai Time Plastic Surgery Hospital, they were randomly divided into observation group and control group. In the observation group, only the cortical slice of costal cartilage with perichondrium was cut and the continuity of costal cartilage was preserved. While in the control group, with the superficial perichondrium preserved, the whole costal cartilage was dissected first, and then pruned it and harvested the cortical slice of costal cartilage with perichondrium. The operation were performed by the same clinicians in both groups. Different variables were compared between the two groups, including the operation time, intraoperative blood loss, length of incision, the degree of chest pain after postoperative 6, 24, 72 h, 1 week, the incidence of intraoperative complications and so on. The severity of chest pain was assessed by visual analogue scale (VAS). The measurement data of the two groups were analyzed by t-test, and the enumeration data were analyzed by χ2 test. Results:For both observation group and the control group, 61 patients were included. In the observation group, there were 3 males (4.9%) and 58 females (95.1%), aged (28.6±5.4) years old, and BMI (21.76±1.65) kg/m 2. In the control group, there were 2 males (3.3%) and 59 females (96.7%), aged (45.8±5.7) years old, and BMI (22.25±1.47) kg/m 2. There were no significant differences in gender composition, age and BMI between the two groups ( P>0.05). The double arch stent of nasal tip could be made by the costal cartilage cortical slices obtained in the two groups. In the control group, two cases of pleural rupture occurred and their prognosis was good after effective treatment, with no complications such as hematoma, infection or pleural injury. In the observation group, there were no complications such as hematoma, infection or pleural injury. The operation time, incision length and intraoperative blood loss in the observation group were significantly lower than those in the control group [(18.54±3.62) min vs. (25.75±3.75) min; (1.68±0.26) cm vs. (2.16±0.32) cm; (16.79±7.86) ml vs. (25.46±8.49) ml; P<0.05]. The VAS score in the observation group was lower than that in the control group after postoperative 6, 24, 72 h, 1 week [(2.76±0.62) vs. (3.87±0.68)scores; (2.37±0.45) vs. (3.12±0.55) scores; (1.76±0.45) vs. (2.57±0.53) scores; (1.17±0.44) vs. (1.85±0.51) scores; P<0.05]. Conclusions:Compared with the conventional method of whole costal cartilage harvest, the method of harvesting the costal cartilaginous cortical slice with the costal perichondrium preserved and preserving the continuity of the costal cartilage can reduce the trauma and bleeding, shorten the operation time, simplify the operation process, and significantly reduce the postoperative chest pain.