Latest progress of research on acute abdominal injuries

Porcine spleen as a model organ for blunt injury impact tests: An experimental and histological study

The spleen is a large and highly vascularized secondary lymphatic organ. Spleen injuries are among the most frequent trauma-related injuries in the abdominal region. The aims of the study were to assess the volume fractions of the main splenic tissue components (red pulp, white pulp, trabeculae and reticular fibres) and to determine the severity of splenic injury due to the experimental impact test. Porcine spleens (n = 17) were compressed by 6.22 kg wooden plate using a drop tower technique from three impact heights (50, 100 and 150 mm corresponding to velocities 0.79, 1.24 and 1.58 m/s). The pressure was measured via catheters placed in the splenic vein. The impact velocity was measured using lasers. The severity of induced injuries was analysed on the macroscopic level. The volume fractions of splenic components were assessed microscopically using stereology. The volume fraction of the red pulp was 76.4%, white pulp 21.3% and trabeculae 2.7% respectively. All impact tests, even with the low impact velocities, led to injuries that occurred mostly in the dorsal extremity of the spleen, and were accompanied by bleeding, capsule rupture and parenchyma crushing. Higher impact height (impact velocity and impact energy) caused more severe injury. Porcine spleen had the same volume fraction of tissue components as human spleen, therefore we concluded that the porcine spleen was a suitable organ model for mechanical experiments. Based on our observations, regions around hilum and the diaphragmatic surface of the dorsal extremity, that contained fissures and notches, were the most prone to injury and required considerable attention during splenic examination after injury. The primary mechanical data are now available for the researchers focused on the splenic trauma modelling.

Combined thoracoabdomial injury: Case report

Introduction

Combined thoracoabdominal injuries are the most severe case in the medical practice. Bilateral injuries are rare case in patients and just few cases reported in literature. Diaphragm traumas and pneumothorax are defined as severe trauma leading to injuries of thoracic and abdominal organs. We are describing multiple injuries of abdominal tract and chest causing internal bleeding and hemothorax in patient. Surgical operation was carried out on the right side thoracotomy including revision of the pleural cavity and subphrenic space, closure of the wound, removal of the blood clot and drainage of the pleural with abdominal cavities.

Presentation of case

A 24-years old man was admitted in Emergency Department after penetrating knife wounds of abdominal cavity.

Discussion

X-ray of the tracheobronchial tree (bronchography) showed closed chest injuries, post traumatic hemopneumothorax of the right side.

Conclusion

Surgical repair was conducted by displacing of the organs in chest cavity with lamellar T-shaped retractor, and hemostatic Billroth, Kocher clamps to stop bleeding in the wound.

Quantitative Analysis of Tissue Damage Evolution in Porcine Liver With Interrupted Mechanical Testing Under Tension, Compression, and Shear

In this study, the damage evolution of liver tissue was quantified at the microstructural level under tensile, compression, and shear loading conditions using an interrupted mechanical testing method. To capture the internal microstructural changes in response to global deformation, the tissue samples were loaded to different strain levels and chemically fixed to permanently preserve the deformed tissue geometry. Tissue microstructural alterations were analyzed to quantify the accumulated damages, with damage-related parameters such as number density, area fraction, mean area, and mean nearest neighbor distance (NND). All three loading states showed a unique pattern of damage evolution, in which the damages were found to increase in number and size, but decrease in NND as strain level increased. To validate the observed damage features as true tissue microstructural damages, more samples were loaded to the above-mentioned strain levels and then unloaded back to their reference state, followed by fixation. The most major damage-relevant features at higher strain levels remained after the release of the external loading, indicating the occurrence of permanent inelastic deformation. This study provides a foundation for future structure-based constitutive material modeling that can capture and predict the stress-state dependent damage evolution in liver tissue.