Males typically have high rates of morbidity of primary bladder neck obstruction, while the existing urodynamic examination is invasive and more likely to cause false diagnosis. To build a non-invasive biomechanical detecting system for the male lower urinary tract, a finite element model for male lower urinary tract based on the collodion slice images of normal male lower urinary tract was constructed, and the fluid-structure interaction of the lower urinary tract was simulated based on the real urination environment. The finite element model of the lower urinary tract was validated by comparing the clinical experiment data with the simulation result. The stress, flow rate and deformation of the lower urinary tract were analyzed, and the results showed that the Von Mises stress and the wall shear stress at the membrane sphincter in the normal male lower urinary tract model reached a peak, and there was nearly 1 s delay than in the bladder pressure, which helped to validate the model. This paper lays a foundation for further research on the urodynamic response mechanism of the bladder pressure and flow rate of the lower urinary tract obstruction model, which can provide a theoretical basis for the research of non-invasive biomechanical detecting system.
Three-dimensional finite element model of elbow was established to study the effect of medial collateral ligament (MCL) in maintaining the stability of elbow joint. In the present study a three-dimensional geometric model of elbow joint was established by reverse engineering method based on the computed tomography (CT) image of healthy human elbow. In the finite element pre-processing software, the ligament and articular cartilage were constructed according to the anatomical structure, and the materials and contacts properties were given to the model. In the neutral forearm rotation position and 0° flexion angle, by comparing the simulation data of the elbow joint with the experimental data, the validity of the model is verified. The stress value and stress distribution of medial collateral ligaments were calculated at the flexion angles of elbow position in 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, respectively. The result shows that when the elbow joint loaded at different flexion angles, the anterior bundle has the largest stress, followed by the posterior bundle, transverse bundle has the least, and the stress value of transverse bundle is trending to 0. Therefore, the anterior bundle plays leading role in maintaining the stability of the elbow, the posterior bundle plays supplementary role, and the transverse bundle does little. Furthermore, the present study will provide theoretical basis for clinical recognizing and therapy of elbow instability caused by medial collateral ligament injury.
Objective To evaluate sex determining region of the Y (Sry) as a engrafting track of the transplanted BMSCs survival and new bone formation in the osteonecrosis of the femoral head (ONFH) of rabbit. Methods Fortynine 4-5-month-old New Zealand White rabbits were included, weighing 2.0-2.5 kg, 48 females and 1 male. BMSCs of the rabbits were isolated by density gradient separation method, the third passage cells were marked by 1, 1’-dioctadecyl-3, 3, 3’, 3’-tetramethyl indocarbocyanine perchlorate (DiI) and the concentration of cell suspension was 2.5 × 108/ mL. The animal model of ONFH were establ ished with 48 female rabbits by injecting l iquid nitrogen, and femoral head was not dislocated.The animal model were divided into 3 groups, 16 rabbits in each group. Group A only establ ished animal model as control. Autologous BMSCs (4 μL) marked by DiI was transplanted in the ONFH models of the group B. Allogenic BMSCs (4 μL) marked by DiI was transplanted in ONFH models of the group C. The femoral head were observed by X-ray, HE staining and Masson staining, and the regenerating trabecular volume percentages was determined at 2, 4, 6 and 8 weeks after operation respectively. The examples of the heart, lung, l iver, spleen and kidney were obtained. The transplanted BMSCs were traced by fluorescence microscope, the Sry gene expression was detected by PCR for cells survival. Results All rabbits survived till the end of experiment. The X-ray showed gradual necrosis in the femoral head of group A. HE and Masson staining results indicated that compared with the group A, the recovery condition of the necrotic femoral head in the groups B and C was better. At each time of groups B and C, the regenerating trabecular volume percentages were higher than that of the group A significantly (P lt; 0.01). There was no significant difference between groups B and C (P gt; 0.05). The cells marked by DiI were not founded in the tissues of the heart, lung, l iver, spleen and kidney in groups B and C at each time. PCR showed that the expression of Sry gene were not observed at the heart, lung, l iver, spleen and kidney of three groups at each time. The expression of Sry gene was clearly identified in the femoral head of all 16 rabbits in the group C at each time point. Conclusion Allografting of BMSCs transplanted into the femoral head can survive and induce new bone formation without redistribution.
Objective To investigate the characteristics of patients with crush injury in Wenchuan earthquake and the corresponding operational methods. Methods From May 12th 2008 to June 18th 2008, 202 patients with crush injury of soft tissue were treated, including 110 males and 92 females. Twenty-five patients aged 19 months to 16 years, 129 patients aged 17-60 years and 48 patients aged above 61 years. The crushed time was 30 minutes to 154 hours. Sixty cases of openinjuries were treated by debridement and dressing or suture; 16 cases of damaged extremities (18 l imbs) and 6 cases of acute renal failure due to crush syndrome (8 l imbs) received amputation; 32 cases of interfascial space syndrome crisis (42 l imbs) were treated by fascia cavity decompression; 15 cases received the resection of necrotic muscle for 31 times; and 9 cases received continuous renal replacement therapy (CRRT). Results All the wounds healed except 2 cases which died from intestinal bleeding and intracranial hemorrhage during the treatment of CRRT. Two cases were discharged 8 months after treatment, while the other 198 cases recovered and were discharged 15-120 days after treatment. The average hospital ization time was 53 days. Twenty-two cases (26 l imbs) were fixed with artificial l imbs 3-6 months after amputation and achieved good functional outcome. Conclusion The treatment principle of crush injury is “be active to decompress and be prudent to amputate”, the hardening muscle and the increasing level of creatine kinase and blood potassium are the golden indicators of fascia cavity decompression. Decompression at an earl ier period is preferred when there is a dilemma to choose, and open amputation should be performed when the necrotic muscle is hard to clear or the necrosis boundary is not distinct.