Biomechanical analysis of the impact of fibular osteotomies at tibiotalar joint: A cadaveric study.

BACKGROUND: Osteotomy of the fibula is a common orthopedic procedure performed for various indications, including harvesting fibula for grafting purposes. The effect of fibular osteotomy and need for tibiofibular syndesmotic fixation fusion at different levels on tibiotalar joint is matter of debate. We performed a biomechanical analysis of the impact of fibular osteotomies at different levels and whether the fixation of distal tibiofibular joint mitigates instability caused by the osteotomy. MATERIALS AND METHODS: Six lower limb specimens from fresh adult cadavers were used to prepare leg-foot models. The specimens were assigned to six status according to the level of osteotomy and whether fixation of distal tibiofibular joint was performed or not. Each specimen was then loaded axially to 700 N by the material testing machine, and the tibiotalar joint contact area and peak pressure were measured using an electronic pressure sensor. RESULTS: The contact area and the pressure of tibiotalar joint showed significant changes when compared to the normal specimen. All osteotomy specimens had a decreased tibiotalar contact area and an increased peak pressure. This positively correlated with proximity of level of osteotomy to the lateral malleolus. CONCLUSIONS: Through this study, we found that fibular osteotomy had an adverse effect in terms of decreasing the contact surface of tibiotalar joint that led to increased peak pressure in the joint. However, bone fusion and screw fixation of the distal tibiofibular joint reduced these adverse effects.

Temozolomide loaded PLGA-based superparamagnetic nanoparticles for magnetic resonance imaging and treatment of malignant glioma.

Polysorbate 80 coated temozolomide-loaded PLGA-based superparamagnetic nanoparticles (P80-TMZ/SPIO-NPs) were successfully synthesized and characterized as drug carriers and diagnosis agent for malignant brain glioma. The mean size of P80-TMZ/SPIO-NPs was 220 nm with narrow hydrodynamic particle size distribution. The superparamagnetic characteristic of P80-TMZ/SPIO-NPs was proved by vibration simple magnetometer. P80-TMZ/SPIO-NPs exhibited high drug loading and encapsulation efficiency as well as good sustained drug release performance for 15 days. MTT assay demonstrated the antiproliferative effect of P80-TMZ/SPIO-NPs for C6 glioma cells. Significant cellular uptake of P80-TMZ/SPIO-NPs was evaluated in C6 glioma cells by fluorescence microscopy, Prussian blue staining, and atomic absorption spectrophotometer (AAS) for qualitative and quantitative study, respectively. MRI scanning analyses in vitro indicated that P80-TMZ/SPIO-NPs could be used as a good MRI contrast agent. Polysorbate 80 coated temozolomide-loaded PLGA-based superparamagnetic nanoparticles could be able to promise a multifunctional theragnostic carrier of brain cancer.

Transplantation of adipose-derived stem cells promotes formation of prefabricated flap in a rat model.

Flap prefabrication is started with transposition of a vascular pedicle into a donor area that lacks an axial blood supply. Adipose-derived stem cells (ASCs) have been proven beneficial for promoting neovascularization and tissue regeneration in several animal models. Here we investigated the feasibility of applying ASCs as a novel strategy to promote flap prefabrication, which involves the processes of neovascularization and regeneration. Prefabricated flaps were performed by two-stage procedure in a rat model. At stage one, the right femoral vascular pedicle was dissected and embedded underneath the abdominal flap to form a man-made axial flap. At stage two, the prefabricated abdominal flap was elevated as an island flap based on the implanted femoral vessel. Ninety rats were randomly divided into 3 groups and received allogeneic ASCs, chondrocytes and phosphate-buffered saline (PBS), respectively during the first operation. Eighteen flaps of each group were harvested for vascular endothelial growth factor-A (VEGF-A) protein assay after the first surgery. The other flaps were processed for flap viability measurements by flap survival rate and capillary density after the second surgery. Results demonstrated that the ASCs treated group had higher survival percentage and capillary density of flap as compared with either PBS group or chondrocyte group. Furthermore, the ASC group had the highest level of in vivo VEGF-A among three groups, while the chondrocyte group had the lowest. These results indicate that ASCs are capable of promoting flap prefabrication, and its therapeutic potential is correlated with the angiogenic cytokines such as VEGF-A.

Construction and clinical significance of normal uterine arterial vascular network models.

AIMS: To construct in vitro models of normal uterine arterial vascular network through vascular corrosion casting and explore their characteristics and clinical significances. METHODS: Three sets of uterus, vagina and bilateral adnexa were perfused and cast via uterine artery and ovarian artery, using 25, 20 and 15% chlorinated poly vinyl chloride, respectively, and constructed into models one, two and three of the uterine arterial network correspondingly, followed by observing their characteristics. RESULTS: There existed important similarities and differences among the three models in displaying uterine arterial network: in model one, the uterine arterial trunk, its branches and partial spiral arteries were sharply demonstrated except the tiny ones; model two further displayed the communicating branches between bilateral spiral arteries, the arterial vascular network of ovarian artery and the anastomoses between the arterial blood supply of uterus and ovaries; model three presented the tiny branches, especially the obvious communicating branches, the complete arterial vascular network of ovary and fallopian tube and anastomoses between them. CONCLUSIONS: A panorama of the uterine arterial vascular network is obtained under organic combination of the three models, which is surely promising for clinical teaching, selections of different approaches and interventional therapy in obstetrics and gynecology.

Three-dimensional reconstruction of the uterine vascular supply through vascular casting and thin slice computed tomography scanning.

It was the objective of this study to construct a model of the uterine vascular supply through vascular casting and thin slice computed tomography scanning. This will provide a teaching aide for the understanding of uterine artery embolization (UAE) procedures, as well as normal uterine and ovarian arterial anatomy. Using 20% chlorinated poly vinyl chloride, we infused and cast a set of a normal uterus, vagina and bilateral adnexa through the uterine artery and ovarian artery. After thin slice CT scanning, we obtained the three-dimensional (3D) reconstruction by maximum intensity projection (MIP) and surface-shaded display (SSD), and then observed its figure and characteristics. A model of the uterine vascular supply can be successfully reconstructed by vascular casting and thin slice CT scanning. The 3D reconstruction offers a clear view of the course of the uterine artery and its blood supply distribution. It has two major branches: The intramuscular uterine branch and the cervicovaginal branch (1). Blood supply is generally unilateral, with communicating branches between the two sides and possible anastomoses between the arterial blood supply of the uterus and the ovaries. The major blood supply of the cervix comes from the cervicovaginal branch of the uterine artery, while the vaginal arterial supply derives directly from the internal iliac artery. The CT technique allows real-time 360 degrees rotation and changes in model for in-depth study of the vascular network and its adjacent tissues. It is possible to construct an in vitro uterine arterial network by vascular casting and CT scanning, which can provide unique insight into the female genitourinary system arterial network. Based on this, we can create reconstructions as well as models for different diseases such as leiomyomata, adenomyosis, and endometrial cancer. These models will provide morphological evidence to the interventional therapy and UAE teaching in Obstetrics and Gynecology.

Biomechanical effect of vertebroplasty on the adjacent intervertebral levels using a three-dimensional finite element analysis.

OBJECTIVE: To investigate the biomechanical effect of different volume, distribution and leakage to adjacent disc of bone cement on the adjacent vertebral body by three-dimensional osteoporosis finite element model of lumbar. METHODS: L(4)-L(5) motion segment data of the cadaver of an old man who had no abnormal findings on roentgenograms were obtained from computed tomography (CT) scans. Three-dimensional model of L(4)-L(5) was established with Mimics software, and finite element model of L(4)-L(5) functional spinal unit (FSU) was established by Ansys 7.0 software. The effect of different loading conditions and distribution of bone cement after vertebroplasty on the adjacent vertebral body was investigated. RESULTS: This study presented a validated finite element model of L(4)-L(5) FSU with a simulated vertebroplasty augmentation to predict stresses and strains of adjacent untreated vertebral bodies. The findings from this FSU study suggested the endplate and disc stress of the adjacent vertebral body was not influenced by filling volume of bone cement but unipedicle injection and leakage to the disc of bone cement could concentrate the stress of adjacent endplate. CONCLUSIONS: Asymmetric distributions and leakage of cement into intervertebral disc can improve the stress of endplate in adjacent vertebral body. These results suggest that optimal biomechanical configuration should have symmetric placement and avoid leakage of cement in operation.

[Studies on the hepatic three-dimensional reconstruction and virtual surgery using the hepatic images of the digitized virtual Chinese human female number 1 database].

OBJECTIVE: To study digitized virtual hepatic three-dimensional reconstruction and virtual hepatic surgery. METHODS: The whole series of hepatic images taken from the database of digitized Virtual Chinese Human Female Number 1 (VCH-F1) was employed to reconstruct a three-dimensional (3D) liver. First, studied some algorithms for registration of human liver tissue images, and then, segmented the regions of liver, vein, bile duct, and gallbladder from the images. Based on them, the 3D visualization human liver model was reconstructed. Finally, a 3D visualization demo system of liver was developed based on personal computer and Windows operation system. RESULTS: This demo system of liver provided a graphics user interface to rotate, scale the 3D liver to observe the 3D hepatic structure, and a virtual liver simulation system of resection with primary function. CONCLUSIONS: The study may be beneficial to the future research on digitized virtual hepatic and virtual hepatic surgery, and the 3D visualization demo system of liver may be beneficial to the research on the hepatic structure.

Effect of operation-synchronizing transfusion of apoptotic spleen cells from donor rats on acute rejection of recipient rats after liver transplantation.

AIM: To study effect of operation-synchronizing transfusion of apoptotic spleen cells from donor rats on acute rejection of recipient rats after liver transplantation. METHODS: Two of Wistar rats were chosen randomly for normal liver pathology control and ten of SD rats chosen randomly for liver function control as blank group (no operation). The rest of Wistar and SD rats were divided into four groups: control group (only liver transplantation), Dex group (donors receiving intraperitoneal injection of dexamethasone), SpC group (recipients receiving infusion of spleen cells of donors), Dex-SpC group (recipients receiving infusion of apoptotic spleen cells of donors), with each group except blank group, containing 10 SD rats and 10 Wistar rats, respectively. Wistar rats received liver transplantation from SD rats, in the meantime they received infusion of spleen cells of donors, which were induced by an intraperitoneal injection of dexamethasone (3 mg/(d.kg).b.w) for three days before liver transplantation. The serum alanine transaminase (ALT), total bilirubin (T bili), liver pathological changes and survival time were analysed. Statistical analysis was carried out using SPSS 10.0 for Windows. Differences of the parametric data of ALT in means were examined by one-way ANOVA. Differences of ALT between two groups were examined by LSD. Differences of the nonparametric data of T bili in means and scores of pathology classification for acute rejection were examined by Kruskal-Willis H test. The correlations between ALT and T bili were analysed by Bivariate. Kaplan-Meier curves were used to demonstrate survival distribution. The log-rank test was used to compare the survival data. RESULTS: There were significant differences in ALT of the five groups (F = 23.164 P = 0.000), and ALT in Dex-SpC group was significantly higher than that in blank control, control, Dex, and SpC groups (P = 0.000), and ALT in SpC group was significantly higher than that in blank control (P = 0.000), control (P = 0.004), and Dex groups (P = 0.02). Results of nonparametric analysis of T bili showed that there were differences in T bili of the five groups (chi(2) = 33.265 P = 0.000). T bili in Dex-SpC group was significantly higher than that in blank control, control, Dex, and SpC groups. T bili in SpC group was higher than that in blank control, control, and Dex groups. There were significant differences in scores of pathology classification for acute rejection in each of the groups (chi(2) = 25.933,P = 0.000). The pathologically more serious acute rejection was found in Dex-SPC group than in other groups. No sign of acute rejection was observed in the blank control group. Slight acute rejection was observed in the control group. Slight-moderate acute rejection was observed in the Dex group. Moderate-acute rejection was observed in the SpC group. Severe-acute rejection was observed in the Dex-SpC group. The survival time in Dex-SpC group was shorter than in other groups (statistic = 11.13, P = 0.011). ALT and T bili were positively correlated (r = 0.747, P = 0.000, two-tailed). CONCLUSION: In order to reduce quantity of blood loss from rats after liver transplantation, only one of ALT or T bili is needed for liver function measurement of rats. Simultaneous injection of apoptotic spleen cells from donors induced by dexamethasone to liver transplantation rats aggravates acute rejection. One important mechanism of aggravation of acute rejection may be that apoptotic cells are not removed in time and that dead cells including apoptotic cells release inflammatory factors.

Palmar tilt changes due to distal radius fractures and radiocarpal instability: a biomechanical study.

OBJECTIVE: To investigate the impact of dorsally angulated malunited distal radius fractures on the stability of the radiocarpal joint. METHODS: Eight fresh upper limb specimens from 4 human cadavers were obtained, in which radial osteotomy was performed to prepare models of Frykman I distal radius fracture. Pressure-sensitive film was applied to study the changes in the contact area distribution and the pressure load across the radiocarpal joint in response to palmar tilt variation, and the lateral radiograph of the wrist was taken at the end of pressure loading. RESULTS: When the dorsal tilt exceeded 10 degrees, the radioscaphoid and radiolunate articular contact areas were markedly decreased (P<0.01) and shifted to the dorsal aspect of the radiocarpal joint, where the pressure load was significantly increased (P<0.01). A dorsal radiocarpal subluxation was liable to occur on the sagittal plane when the dorsal tilt exceeded 40 degrees. CONCLUSION: A dorsal tilt over 10 degrees is the most primary cause of radiocarpal instability after a dorsal deformity due to distal radius fractures.