Trajectory optimisation with musculoskeletal integration features for fracture reduction orthopaedic robot.

BACKGROUND: Human body is an integrated system of bones and muscles. To date, there are insufficient studies on the effect of muscles on the trajectory planning of orthopaedic robot. To this end, based on a Stewart-Gough platform (6-UPU) fracture reduction orthopaedic robot, a musculoskeletal trajectory optimisation method was constructed for the interference of soft tissue during the reduction process. METHODS: Firstly, pose description of the fracture reduction orthopaedic robot was introduced, and its working space was analysed. Secondly, an improved Hill muscle theory was used to construct the musculoskeletal system, and finite element analysis (FEA) was carried out. Thirdly, particle swarm optimisation (PSO) with variable weights was imported, and fracture reduction trajectory planning was obtained by quintic polynomial in the workspace. Then mathematical model for trajectory optimisation was presented, and targets of musculoskeletal optimisation were extracted, which include muscle energy consumption, robot-assisted repositioning time and trajectory length. In this sense, musculoskeletal integration trajectory optimisation method was put forward. Finally, comparative optimisation simulation with skeleton only and bone and muscle together were tested, and safety experiment with musculoskeletal integration was conducted. RESULTS: A cone shape workspace was got, whose range can be defined as 635.14 mm on the X axis, 720 mm on the Y axis, and 240 mm on the Z axis, respectively. Besides, different FEA displacements revealed the effect of bone and muscle on the movement of the robot. Moreover, the optimal results with and without muscle had showed different movement time: the former consumed about 27 s, but the latter spent about 25 s. Additionally, the speed and acceleration of the drive rods can be obtained from zero to zero during the reset. CONCLUSIONS: The results show that the optimised trajectory obtained with this method is safe and reliable. Furthermore, the presence of muscle has great influence on the trajectory of robot, which could prolong the reduction time so as to prevent the occurrence of uneven soft and hard traction rate problem. This paper could be helpful for the future trajectory planning study of fracture reduction orthopaedic robot.

Automatic Femoral Deformity Analysis Based on the Constrained Local Models and Hough Forest.

Clinically, Taylor spatial frame (TSF) is usually used to correct femoral deformity. The first step in correction is to analyze skeletal deformities and measure the center of rotation of angulation (CORA). Since the above work needs to be done manually, the doctor's workload is heavy. Therefore, an automatic femoral deformity analysis system was proposed. Firstly, the Hough forest and constrained local models were trained on the femur image set. Then, the position and size of the femur in the X-ray image were detected by the trained Hough forest. Furthermore, the position and size were served as the initial values of the trained constrained local models to fit the femoral contour. Finally, the anatomical axis line of the proximal femur and the anatomical axis line of the distal femur could be drawn according to the fitting results. According to these lines, CORA can be found. Compared with manual measurement by doctors, the average error of the hip joint orientation line was 1.7°, the standard deviation was 1.75, the average error of the anatomic axis line of the proximal femur was 2.9°, and the standard deviation was 3.57. The automatic femoral deformity analysis system meets the accuracy requirements of orthopedics and can significantly reduce the workload of doctors.

For nasotracheal intubation, which nostril results in less epistaxis: right or left?: A systematic review and meta-analysis.

BACKGROUND: Nasotracheal intubation is usually required in patients undergoing oromaxillofacial, otolaryngological or plastic surgery to prevent the airway encroaching into the operating field. Epistaxis is the most common complication, but which nostril is associated with a lower incidence and severity of epistaxis is still unclear. OBJECTIVE: When both nostrils are patent, to determine the preferred nostril for nasotracheal intubation under general anaesthesia. DESIGN: A systematic review and meta-analysis of randomised controlled trials (RCTs). The primary outcome was the incidence of epistaxis and the secondary outcomes included the incidence of severe epistaxis, the time required to pass the tube through the nasal passage and total intubation time. DATA SOURCES: PubMed, Embase and the Cochrane Register of Controlled Trials were searched from database inception to 1 March 2020. ELIGIBILITY CRITERIA: The only studies included were RCTs comparing epistaxis related to nasotracheal intubation via right or left nostril, in adult surgery patients undergoing general anaesthesia. RESULTS: Ten RCTs with 1658 patients were included. Compared with the left nostril, intubation via the right nostril was associated with a significantly lower incidence of epistaxis: risk ratio (RR) and 95% confidence intervals (CI) were 0.78 (0.62 to 0.99), P = 0.04: a lower incidence of severe epistaxis (five studies, n=923), RR 0.40 (0.22 to 0.75), P = 0.004: and a shorter intubation time (three studies, n=345), mean difference -7.28 (-14.40 to -0.16) seconds, P = 0.05. In two studies (n=310), no significant difference between the right and left nostril was observed in the time to pass the tube through the nasal passages, mean difference -0.59 (-1.95 to 0.77) s, P = 0.40. CONCLUSION: On the basis of the current available evidence, when both nostrils are patent, the right nostril is more appropriate for nasotracheal intubation, with a lower incidence and severity of epistaxis and faster intubation time. TRIAL REGISTRATION: The study protocol has been registered in PROSPERO (CRD42020169949).

Hill-based musculoskeletal model for a fracture reduction robot.

BACKGROUND: The introduction of fracture reduction robot can solve the problem of large reduction forces during fracture reduction surgeries and the need to collect multiple medical images. However, because its safety has not been certified, there are few academic achievements on this type of robot. To calculate the safety factor during its operation, a musculoskeletal model needs to be established to study the constraints of muscles on the robot. The existing academic achievements of musculoskeletal modelling are mainly for application such as rehabilitation treatment and collision in car accidents. METHODS: A musculoskeletal model applied to the fracture reduction robot is proposed in this paper. First, by comparing the characteristics of mainstream muscle models and combining the biological characteristics of the anesthetised muscles, the Hill model was selected as the muscle model for this study. Second, based on the motion composition of six spatial degrees of freedom, five basic fractural malposition situations are proposed. Then, a 170-cm tall male musculoskeletal model was built in Opensim. Based on this model, the muscle force curves of the above malposition situations are calculated. Finally, a similar musculoskeletal model was established in Adams, and the accuracy of its muscle force data was tested. The study is approved by the ethics committee of the Rehabilitation Hospital, National Research Center for Rehabilitation Technical Aids, Beijing, China. RESULTS: The muscle force curve of Opensim and Adams model under situations of five basic malposition are compared. Most of the correlation coefficients are in the range of 0.98-0.99. The overall correlation coefficient is greater than 0.95. CONCLUSIONS: The simulation results prove that this model can be used for the safety assessment of the fracture reduction robots. This model will be served as an environmental constraint to study the control of fracture reduction robot.