Objective:To investigate the efficacy and safety of three-dimensional navigation template assisted osteotomy for fracture malunion of lateral condyle of humerus in children.Methods:Eighteen children with ma-lunion of fracture of lateral condyle of humerus were treated in Southern Medical University Third Affiliated Hospital from August 2012 to December 2019 and analyzed retrospectively.Among them, 12 cases were treated with routine ope-ration: according to CT reconstruction and empirical osteotomy during the operation, the location of deformity was analyzed.Six cases were treated with navigation template assisted osteotomy: according to the CT data of bilateral elbow joints, a three-dimensional bone model was established, and the coronal and sagittal deformities of the distal humerus were evaluated by comparing the images of the distal humerus of the affected side with the distal humerus of the healthy side, so as to determine the best plane of osteotomy and the target position of reduction.The preoperative simulation was carried out on the computer, and the osteotomy navigation template and reduction navigation template were designed.The navigation template was printed out with a 3D printer.During the operation, the osteotomy was corrected with the assistance of navigation template, and the broken end of osteotomy was fixed with hollow screw and fixed with 80 degree flexion plaster.The X-ray films of the two groups were reexamined regularly after operation.The amount of intraoperative blood loss, operation time, incidence of postoperative complications (necrosis of humeral head and trochlea, delayed ulnar nerve paralysis, and bone nonunion) and the recovery of flexion and the extension function of elbow joint were observed in the 2 groups.Results:The elbow joint activity of all children basically returned to normal, the orthopedic site of osteotomy achieved bony healing, and the orthopedic effects were satisfactory.All the 18 cases were followed up for 6-24 months (mean 15 months). According to the postoperative Dhillon score, the navigation template group was excellent in 1 case and better in 5 cases, while in the routine group, 11 cases were batter and 1 case was fair.There were no significant differences in Dhillon score between the 2 groups after operation ( P>0.05). There were no significant differences in the range of the motion of elbow joint between the 2 groups ( P>0.05). In the comparison of operation time and intraoperative blood loss, the navigation template group [(200.0±24.2) min, (85.0±10.9) mL]was better than the routine group[(232.0±20.1) min, (139.1±18.3) mL](all P<0.001). Conclusions:The application of three-dimensional humerus reconstruction and mirror image contrast to evaluate the distal humerus deformity of the affected side, and the design of osteotomy and reduction navigation template auxiliary operation can restore the normal anatomical structure of elbow joint to the greatest extent.Accurate correction, and the function of elbow joint recover well after operation, which optimizes the operation procedure, improves the safety and effectiveness of the operation.

OBJECTIVETo study the biomechanical mechanism of head injuries beaten with sticks, which is common in the battery or assaultive cases.

METHODSIn this study, the Hybrid-III anthropomorphic test device and finite element model (FEM) of the total human model for safety (THUMS) head were used to determine the biomechanical response of head while being beaten with different sticks. Total eight Hybrid-III tests and four finite element simulations were conducted. The contact force, resultant acceleration of head center of gravity, intracranial pressure and von Mises stress were calculated to determine the different biomechanical behavior of head with beaten by different sticks.

RESULTSIn Hybrid-III tests, the stick in each group demonstrated the similar kinematic behavior under the same loading condition. The peak values of the resultant acceleration for thick iron stick group, thin iron stick group, thick wooden stick group and thin wooden stick group were 203.4 g, 221.1 g, 170.5 g and 122.2 g respectively. In finite element simulations, positive intracranial pressure was initially observed in the frontal comparing with negative intracranial pressure in the contra-coup site. Subsequently the intracranial pressure in the coup site was decreasing toward negative value while the contra-coup intracranial pressure increasing toward positive values.

CONCLUSIONSThe results illustrated that the stiffer and larger the stick was, the higher the von Mises stress, contact force and intracranial pressure were. We believed that the results in the Hybrid-III tests and THUMS head simulations for brain injury beaten with sticks could be reliable and useful for better understanding the injury mechanism.

Biomechanical Phenomena ; Brain Injuries ; etiology ; Finite Element Analysis ; Humans ; Intracranial Pressure ; Manikins

Objective: To study the effects of three different granular fats on proliferation, differentiation and migration of adipose-derived stem cells. Methods: Ten patients were selected for lumbar liposuction. The adipose tissue was obtained with different sized side-hole fat aspiration devices: 10 ml of Macrofat (n=10), 10 ml of Microfat (n=10) and 10 ml of Nanofat (n=10). Enzyme digestion method was used to separate and extract adipose-derived stem cells(ADSCs). The differences of vascular matrix components in these 3 kinds of fat sources were analyzed. XTT assay was used to detect proliferation and growth ability. The migration ability of the cell injury model was observed in vitro, and the multi-directional differentiation ability was compared by the analysis of adipogenic and osteogenic induction. The experimental data were analyzed using SPSS 13.0 software. One-Way ANOVA was used to compare the difference of multiple groups. P<0.05 was considered as statistically significant. Results: The detection of adipose-derived stem cells was by flow cytometry and it showed Macrofat, Microfat and Nanofat was(4.23±0.37)×10⁵, (2.29±0.33)×10⁵ and(1.56±0.16)×10⁵. The content of fat-derived stem cells in Macrofat was the highest, followed by Microfat, and the content of Nanofat was the least (F=209.533, P<0.001). XTT assay showed that the proliferative ability of adipose-derived stem cells in the first two generations of Macrofat was the highest, followed by Microfat, while the proliferation of Nanofat was the lowest (the absorbance in 3 groups increased in a time-dependent manner). There was no significant difference in the proliferative capacity of the third generation of 3 groups (the absorbance of these 3 groups were compared at each time point). The cellular trauma model showed that the first generation of Macrofat-derived stem cells had the best migration ability, followed by Microfat, while the Nanofat had the weakest migration ability(Compared with the remaining area of wounds at 0 h, 12 h, 24 h point between the three groups, F=306.370, 1409.907, P<0.001). From the second generation, the migration ability of each group of ADSCs gradually self-repaired, and the migration ability at 12 h was similar to that of the first generation (F=11.410, P<0.001), but there was no significant difference in 24 h (F=0.070, P=0.933). Oil red O and alizarin red staining showed that the first generation of Macrofat and Microfat had better fat-forming and osteogenic differentiation ability than Nanofat(F=523.532, 620.022, P<0.001). However, there was no significant change after the second generation (F=2.144, 0.866, P=0.137, 0.432). Conclusions In the process of adipose tissue extraction of Nanofat, the production and activity of adipose-derived stem cells was impacted. However, in the process of culture and passage, the cell activity, proliferation ability, migration ability and differentiation ability can be achieved through self-repair, evenclose to the level of Macrofat or Microfat.

Nasal drug delivery efficiency is highly dependent on the position in which the drug is deposited in the nasal cavity. However, no reliable method is currently available to assess its impact on delivery performance. In this study, a biomimetic nasal model based on three-dimensional (3D) reconstruction and three-dimensional printing (3DP) technology was developed for visualizing the deposition of drug powders in the nasal cavity. The results showed significant differences in cavity area and volume and powder distribution in the anterior part of the biomimetic nasal model of Chinese males and females. The nasal cavity model was modified with dimethicone and validated to be suitable for the deposition test. The experimental device produced the most satisfactory results with five spray times. Furthermore, particle sizes and spray angles were found to significantly affect the experimental device's performance and alter drug distribution, respectively. Additionally, mometasone furoate (MF) nasal spray (NS) distribution patterns were investigated in a goat nasal cavity model and three male goat noses, confirming the in vitro and in vivo correlation. In conclusion, the developed human nasal structure biomimetic device has the potential to be a valuable tool for assessing nasal drug delivery system deposition and distribution.