ObjectiveTo investigate the effectiveness of repair procedure using biological mesh with Onlay-Reinforce technique in patients with perineal hernia. MethodsBetween January 2005 and December 2012, 9 patients with perineal hernia after laparoscopic abdominoperineal resection for rectal cancer (Miles operation) were treated. There were 3males and 6 females with a mean age of 70 years (range, 61-78 years). The disease duration was 1-9 months (mean, 4.5 months). The most beginning symptom was distending pain in perineal region, and then reducible mass was found without bowel incarceration. All patients underwent hernia repair using biological mesh with Onlay-Reinforce technique through original perineal incision. ResultsThe hernial size was 9.8-20.5 cm2 (mean, 16.0 cm2); the size of biological mesh was 58-80 cm2 (mean, 70.2 cm2); and the intraoperative blood loss was 10-80 mL (mean, 50.5 mL). All of the patients underwent repair operation successfully. The operation time was 45-90 minutes (mean, 60.6 minutes); and the hospitalization time was 4-7 days (mean, 5.9 days). One patient had urine retention, which was relieved after 7 days indwelling catheter. All the wounds healed by first intention without infection. The patients were followed up 14.5-60.7 months (mean, 37.8months). No chronic pain, obvious foreign body sensation, or hernia recurrence developed. ConclusionUse of biological mesh with Onlay-Reinforce technique for the repair of perineal hernia after Miles operation is safe and effective.
This paper studies the active force characteristics of the neck muscles under the condition of rapid braking, which can provide theoretical support for reducing the neck injury of pilots when carrier-based aircraft blocks the landing. We carried out static loading and real vehicle braking experiments under rapid braking conditions, collected the active contraction force and electromyography (EMG) signals of neck muscles, and analyzed the response characteristics of neck muscle active force response. The results showed that the head and neck forward tilt time was delayed and the amplitude decreased during neck muscle pre-tightening. The duration of the neck in the extreme position decreased, and the recovery towards the seat direction was faster. The EMG signals of trapezius muscle was higher than sternocleidomastoid muscle. This suggests that pilots can reduce neck injury by pre-tightening the neck muscles during actual braking flight. In addition, we can consider the design of relevant fittings for pre-tightening the neck muscles.
Objective To investigate the feasibility and clinical outcomes of minimally invasive sternal depression by autologous force for the correction of pectus carinatum. Methods Between October 2011 and September 2015, 22 pectus carinatum patients underwent minimally invasive surgical correction of pectus carinatum in Tongji Hospital. Clinical data of 22 patients were retrospectively analyzed. There were 19 males and 3 females with a mean age of 12.00±2.87 years, ranging from 6 to 15 years. Among them, 17 patients were symmetric malformation, and the others were asymmetric. Preoperative chest CT scan was performed on 14 patients. Haller index was 1.65-2.23 (1.97±0.15). All the patients underwent the minimally invasive surgical correction of pectus carinatum with a NUSS bar via sternal depression by autologous force. Results All the operations were completed successfully. The mean operation time was 55-120 (83.73±16.62) min and blood loss volume was 10-50 (28.18±11.63) ml. The mean postoperative hospital stay was 3-6 (4.23±1.17) d. Postoperative complications included wound infection in 2 patients, minor pneumothorax in 3 patients, who were cured by conservative treatment. One patient suffering postoperative hydropneumothorax received drainage. All the patients were followed up for 6-48 months after discharge and very satisfied with the chest appearance following surgery. No patient complained of persistent pain. There was no displacement of the bar or the stabilizers. Nine patients underwent the removal of the NUSS bar without pectus carinatum recurrence. Conclusion Minimally invasive sternal depression by autologous force simplifies the procedure of correction of pectus carinatum with reliable and satisfactory outcomes.
In order to investigate in greater detail the two methods based on Hertz model for analyzing force-distance curve obtained by atomic force microscopy, we acquired the force-distance curves of Hela and MCF-7 cells by atomic force microscopy (AFM) indentation in this study. After the determination of contact point, Young's modulus in different indentation depth were calculated with two analysis methods of "two point" and "slope fitting". The results showed that the Young's modulus of Hela cell was higher than that of MCF-7 cell,which is in accordance with the F-actin distribution of the two types of cell. We found that the Young's modulus of the cells was decreased with increasing indentation depth and the curve trends by "slope fitting". This indicated that the "slope fitting" method could reduce the error caused by the miscalculation of contact point. The purpose of this study was to provide a guidance for researcher to choose an appropriate method for analyzing AFM indentation force-distance curve.
Forced oscillation technique (FOT) is an active method to test pulmonary function, which can derive the mechanical characteristics of the respiratory system with liner system identification theory by pushing in an oscillation air signal and measuring the changes of output pressure and flow. A pulmonary function determination system was developed based on the FOT in this paper. Several critical technologies of this determination system were analyzed, including the selection criteria of oscillation air generator, pressure and flow sensor, the signal design of oscillation air generator, and the synchronous sampling of pressure and flow data. A software program on LabVIEW platform was set up to control the determination system and get the measuring data. The performance of sensors and oscillation air generator was verified. According to the frequency response curve of the pressure, the amplitude of driving signal to the oscillation air generator was corrected at the frequency range between 4~40 Hz. A simulation experiment was carried out to measure the respiratory impedance of the active model lung ASL5000 and the results were close to the setting values of the model lung. The experiment testified that the pulmonary function determination system based on FOT had performance good enough to provide a tool for the in-depth research of the mechanical properties of the respiratory system.
Objective To review the recent research progress of the bioreactor biophysical factors in cartilage tissue engineering. Methods The related literature concerning the biophysical factors of bioreactor in cartilage tissue engineering was reviewed, analyzed, and summarized. Results Oxygen concentration, hydrostatic pressure, compressive force, and shear load in the bioreactor system have no unified standard parameters. Hydrostatic pressure and shear load have been in controversy, which restricts the application of bioreactors. Conclusion The biophysical factors of broreactor in cartilage tissue engineering have to be studied deeply.
A new diamond-based variable spring-mass model has been proposed in this study. It can realize the deformation simulation for different organs by changing the length of the springs, spring coefficient and initial angle. The virtual spring joined in the model is used to provide constraint and to avoid hyperelastic phenomenon when excessive force appears. It is also used for the calculation of force feedback in the deformation process. With the deformation force feedback algorithm, we calculated the deformation area of each layer through screening effective particles, and contacted the deformation area with the force. This simplified the force feedback algorithm of traditional spring-particle model. The deformation simulation was realized by the PHANTOM haptic interaction devices based on this model. The experimental results showed that the model had the advantage of simple structure and of being easy to implement. The deformation force feedback algorithm reduces the number of the deformation calculation, improves the real-time deformation and has a more realistic deformation effect.
The anterior cruciate ligament (ACL) reconstruction mostly relies on the experience of surgeons. To improve the effectiveness and adaptability of the tension after ACL reconstruction in knee joint rehabilitation, this paper establishes a lateral force measurement model with relaxation characteristics and designs an on-line stiffness measurement system of ACL. In this paper, we selected 20 sheep knee joints as experimental material for the knee joint stability test before the ACL reconstruction operation, which were divided into two groups for a comparative test of single-bundle ACL reconstruction through the anterolateral approach. The first group of surgeons carried out intraoperative detection with routine procedures. The second group used ACL on-line stiffness measurement system for intraoperative detection. After that, the above two groups were tested for postoperative stability. The study results show that the tension accuracy is (− 2.3 ± 0.04)%, and the displacement error is (1.5 ± 1.8)%. The forward stability, internal rotation stability, and external rotation stability of the two groups were better than those before operation (P < 0.05). But the data of the group using the system were closer to the preoperative knee joint measurement index, and there was no significant difference between them (P > 0.05). The system established in this paper is expected to help clinicians judge the ACL reconstruction tension in the operation process and effectively improve the surgical effect.
In existing vascular interventional surgical robots, it is difficult to accurately detect the delivery force of the catheter/guidewire at the slave side. Aiming to solve this problem, a real-time force detection system was designed for vascular interventional surgical (VIS) robots based on catheter push force. Firstly, the transfer process of catheter operating forces in the slave end of the interventional robot was analyzed and modeled, and the design principle of the catheter operating force detection system was obtained. Secondly, based on the principle of stress and strain, a torque sensor was designed and integrated into the internal transmission shaft of the slave end of the interventional robot, and a data acquisition and processing system was established. Thirdly, an ATI high-precision torque sensor was used to build the experimental platform, and the designed sensor was tested and calibrated. Finally, sensor test experiments under ideal static/dynamic conditions and simulated catheter delivery tests based on actual human computed tomography (CT) data and vascular model were carried out. The results showed that the average relative detection error of the designed sensor system was 1.26% under ideal static conditions and 1.38% under ideal dynamic stability conditions. The system can detect on-line catheter operation force at high precision, which is of great significance towards improving patient safety in interventional robotic surgery.
Posterior-stabilized total knee prostheses have been widely used in orthopedic clinical treatment of knee osteoarthritis, but the patients and surgeons are still troubled by the complications, for example severe wear and fracture of the post, as well as prosthetic loosening. Understanding the in vivo biomechanics of knee prostheses will aid in the decrease of postoperative prosthetic revision and patient dissatisfaction. Therefore, six different designs of posterior-stabilized total knee prostheses were used to establish the musculoskeletal multibody dynamics models of total knee arthroplasty respectively, and the biomechanical differences of six posterior-stabilized total knee prostheses were investigated under three simulated physiological activities: walking, right turn and squatting. The results showed that the post contact forces of PFC Sigma and Scorpio NGR prostheses were larger during walking, turning right, and squatting, which may increase the risk of the fracture and wear as well as the early loosening. The post design of Gemini SL prosthesis was more conductive to the knee internal-external rotation and avoided the edge contact and wear. The lower conformity design in sagittal plane and the later post-cam engagement resulted in the larger anterior-posterior translation. This study provides a theoretical support for guiding surgeon selection, improving posterior-stabilized prosthetic design and reducing the prosthetic failure.