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Objective To investigate the clinical efficacy and advantages of cannulated screw internal fixation assisted by the orthopaedic surgery robot positioning system in the treatment of femoral neck fractures. Methods The clinical data of 128 patients with femoral neck fractures which had been treated with cannulated screw internal fixation from January 2016 to July 2018 were retrospectively analyzed. Among them, 63 patients were treated with cannulated screw assisted by orthopedic robot positioning system (orthopaedic surgery robot group), and 65 patients were treated with traditional cannulated screw (traditional surgery group). The operation time, number of intraoperative fluoroscopy, number of guide needle placements, and the amount of operative blood loss were compared between the two groups. The success rate of one‐time nail placement and the fracture healing rate were calculated. Fracture healing and internal fixation were observed. The hip joint function was evaluated by the Harris hip score 1 year after operation. Results All patients were followed up for 12 to 24 months. The operation time was 65.70 ± 9.87 min in the robot group and 73.74 ± 9.78 min in the traditional group. The number of intraoperative fluoroscopy was 13.67 ± 4.39 times in the robot group and 17.09 ± 4.02 times in the traditional group. The number of guide needle placements was 9.95 ± 3.72 times in the robot group and 13.78 ± 4.39 times in the traditional surgery group. The success rate of one‐time nail placement was 100% (63/63) in the robot group and 49.23% (32/65) in the traditional group. The amount of operative blood loss was 15.25 ± 6.21 mL in the robot group and 25.51 ± 6.97 mL in the traditional group. Compared with the traditional group, the robot group had shorter operation time, less fluoroscopy, less needle placement, less bleeding, and higher success rate of one‐time nail placement. There was a significant difference between the two groups (P < 0.05). In the robot group, there was no infection, loosening of internal fixation, fracture displacement, and osteonecrosis of femoral head during the follow‐up period. The fracture healing rate was 100% (63/63). In the traditional group, there were two cases of loosening of internal fixation and one case of osteonecrosis of femoral head during the follow‐up period. The fracture healing rate was 100% (65/65). All patients were evaluated for hip joint function 1 year after operation. The Harris hip score in the robot group was 86.86 ± 4.74, and the Harris hip score in the traditional surgery group was 83.08 ± 5.44. Compared with the traditional group, the Harris hip score in the robot group was higher than that in the traditional group. There was significant difference between the two groups (P < 0.05). The excellent and good rate were 92.06% (58/63) in the robot group and 80% (52/65) in the traditional group. There was no significant difference between the two groups (P > 0.05). Conclusion Cannulated screw internal fixation assisted by the orthopaedic surgery robot positioning system is ...

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Spontaneous spinal epidural hematoma (SSEH) during pregnancy is rare and may result in permanent damage if not promptly treated. There were few studies discussing the etiology, presentation and treatment of SSEH during pregnancy. The authors describe a case of spontaneous cervical epidural hematoma during pregnancy, which was diagnosed by magnetic resonance imaging (MRI) and managed with surgical evacuation. A retrospective review of a case of spontaneous epidural hematoma of spine during pregnancy was performed. The clinical features, diagnoses, treatments and outcomes of all cases were analyzed. Precise diagnosis without delay and rapid surgical treatment are essential for the management of SSEH during pregnancy.

Objective To compare the clinical efficacy of intramedullary nail fixation for intertrochanteric fractures assisted by orthopaedic robot navigation and the traditional intramedullary nail fixation in elderly patients, and to investigate the application advantages of intramedullary nail fixation for femoral intertrochanteric fractures assisted by orthopaedic robot navigation in the elderly. Methods Among the 51 patients with intertrochanteric fractures who were selected from April 2015 to September 2017 in the Affiliated Hospital of Chengdu University, 25 patients underwent the intramedullary nail fixation assisted by orthopaedic robot navigation (orthopaedic robot navigation surgery group) and 26 patients underwent the traditional intramedullary nail fixation (traditional surgery group). The operation time, the number of intraoperative fluoroscopy images taken, the frequency of guide pins inserted into the femoral marrow cavity, the amount of intraoperative bleeding, and the one‐time success rate of the guide pin inserted into the femoral marrow cavity were recorded. Fracture healing and internal fixation were observed. The Harris score was used to evaluate hip joint function 1 year after surgery. Results All patients were followed up for 12–24 months. The operation time was 65.44 ± 8.01 min in the orthopaedic robot navigation surgery group and 77.50 ± 16.64 min in the traditional surgery group. The number of intraoperative fluoroscopy images taken was 10.28 ± 0.61 in the orthopaedic robot navigation surgery group and 13.23 ± 1.75 in the traditional surgery group. The frequency of guide pins inserted into the femoral marrow cavity was 1.00 ± 0.00 times in the orthopaedic robot navigation surgery group and 2.46 ± 1.10 times in the traditional surgery group. The one‐time success rate of intramedullary pin puncture was 100% (25/25) in the orthopaedic surgical robot navigation surgery group and 19.23% (5/26) in the traditional surgery group. The amount of surgical bleeding was 90.80 ± 14.98 mL in the orthopaedic robot navigation surgery group and 118.46 ± 32.21 mL in the traditional surgery group. Compared with the traditional surgery group, the operation time of the orthopaedic surgical robot navigation surgery group was shorter (P < 0.05), the number of intraoperative fluoroscopy images taken was fewer (P < 0.05), the frequency of guide pins inserted into the femoral marrow cavity was lower (P < 0.05), the one‐time success rate of intramedullary pin puncture was higher (P < 0.05), and the amount of surgical bleeding was less (P < 0.05). One year after surgery, fracture healing occurred in both groups without failure of internal fixation or fracture displacement. The Harris score of hip function in the orthopaedic robot navigation surgery group was 86.68 ± 6.23 and that in the traditional surgery group was 82.69 ± 6.85. It was higher than that in the traditional surgery group (P < 0.05). The fine rate of hip joint function in the orthopaedic robot navigation surgery group was 84.00% (21/25) and that in the tradition...

Convolutional neural networks (CNNs) have been widely used in synthetic aperture radar (SAR) target recognition. Traditional CNNs suffer from expensive computation and high memory consumption, impeding their deployment in real-time recognition systems of SAR sensors, as these systems have low memory resources and low speed of calculation. In this paper, a micro CNN (MCNN) for real-time SAR recognition system is proposed. The proposed MCNN has only two layers, and it is compressed from a deep convolutional neural network (DCNN) with 18 layers by a novel knowledge distillation algorithm called gradual distillation. MCNN is a ternary network, and all its weights are either −1 or 1 or 0. Following a student-teacher paradigm, the DCNN is the teacher network and MCNN is its student network. The gradual distillation makes MCNN a better learning route than traditional knowledge distillation. The experiments on the MSTAR dataset show that the proposed MCNN can obtain a high recognition rate which is almost the same as the DCNN. However, compared with the DCNN, the memory footprint of the proposed MCNN is compressed 177 times, and the calculated amount is 12.8 times less, which means that the proposed MCNN can obtain better performance with the smaller network. INDEX TERMS SAR target recognition, micro convolutional neural network, knowledge distillation, model compression, ternary network.

The behavior of a shear-driven thin liquid film at a sharp expanding corner is of interest in many engineering applications. However, details of the interaction between inertial, surface tension, and gravitational forces at the corner that result in partial or complete separation of the film from the surface are not clear. A criterion is proposed to predict the onset of shear-driven film separation from the surface at an expanding corner. The criterion is validated with experimental measurements of the percent of film mass separated as well as comparisons to other observations from the literature. The results show that the proposed force ratio correlates well to the onset of film separation over a wide range of experimental test conditions. The correlation suggests that the gas phase impacts the separation process only through its effect on the liquid film momentum.