Treatment of Unstable Injury of Pelvic Bones in Pregnant (Case Report)

Summary. There is no doubt in the relevance of the problem of treatment of patients with unstable fractures of pelvic bones, since these injuries involve a threat to the patient's life in the early period and often lead to disability in the future. This article presents a rare case of treatment of a patient with an unstable pelvis injury, while being 16 weeks pregnant. Patient A., born 1993, was admitted after a road accident injury. The examinations included: X-ray, CT, ultrasound, and gynecologist consultation. The patient was diagnosed with closed bilateral fracture of the pubic and ischial bones with displacement; rupture of the left sacroiliac joint with the boundary fracture of the sacrum (61-С1.3 by the Tile-AO-ASIF classification). The patient was 16 weeks pregnant. The surgery – open reduction and extramedullary metalosteosynthesis – was performed at the 9th day after the injury. The patient was discharged to outpatient treatment at the 12th day after the surgery. She started walking on crutches 3 weeks after the surgery; no additional support was needed since 1.5 months after the surgery. The patient gave birth at 39 weeks by surgical intervention (caesarean section). The baby's condition was assessed as 8 according to the Apgar scale. At the control examination 10 months after the surgery, musculoskeletal function of the patient was fully restored.

Numerical Study of Thermal Shock Damage Mechanism of Polycrystalline Ceramics

A dual-scale model is proposed to study the effect of microstructure parameters (grain size and grain boundary fracture energy) on the thermal shock damage mechanism on an example of alumina. At microscale, representative volume element (RVE) models generated by Voronoi tessellation are simulated to obtain the mechanical parameters for macro models. At macroscale, a coupled thermomechanical model based on the finite–discrete element method (FDEM) is applied to simulate the crack nucleation and propagation. Energy dissipation (ALLDMD) is introduced to investigate the thermal shock cracking mechanism by combining crack patterns and crack density, which indicates that decreasing grain size and increasing grain boundary fracture energy have a positive effect on thermal shock resistance. The proposed models not only predict the critical stress temperature which is well consistent to the theoretical thermal shock resistance factor, but also quantify the two previously unconsidered stages (crack nucleation and crack instability stage). Our models suggest the crack nucleation and instability will not occur immediately when the model reaches critical stress, but the models can sustain for higher temperature difference. The thermal shock damage mechanism and the influence of microstructural parameters on thermal shock resistance have also been discussed in detail.