Patho-mechanical comparative morpho-characterization of contre-coup injuries of liver by cadaveric experimental simulation for medico-legal and forensic implications

Abstract

Background: Liver is the most common organ to get injured in cases of blunt force trauma to the abdomen (BFTA). It is the 2nd commonest organ after brain to sustain injuries out of all the trauma related fatalities. However, the literature about contre-coup injuries to the liver due to BFTA is scarce in-spite of the high mortality rates seen out of injury to this particular organ.

Purpose: The authors intended to systematize the characteristic morphogenesis of the contre-coup injuries of the liver on the basis of the patho-mechanics involved in various types of BFTA.

Methodology: One hundred and sixty three cases of BFTA were identified, and interpretation was attempted for the contre-coup rupture of the liver seen in twenty out of all the trauma related fatalities that presented for post-mortem examination during the study period. However, the mechanics of the pattern of the rupture injuries to the liver were indiscernible. This motivated the authors to conduct the comparative characterization of injuries to the liver by experimental simulation of BFTA after necessary permission via inflicting pre-calculated forces on unclaimed cadavers.

Results: The patterns of contre-coup rupture/s of liver were established in all the twenty out of one sixty-three cases of BFTA. The rupture depicted patterns of injury in the situations of - 1) strong hits with a limited surface trauma, 2) very strong hits with a generalized surface trauma, 3) and collision with a solid surface resulting due to fall onto the side of the abdomen. The causative mechanism discerned was deformation of the liver, followed by its parenchymal rupture due to the shear and strain types of force/s consequent upon tissue compression. The minimum force and energy of impact required for the liver to rupture was estimated to be 2000 N and 141.5 J.

Conclusion: This series of the simulation experiments revealed two variants of liver rupture in the contre-coup impact zone. The pattern of injury was maintained in cases, those studied at post-mortem examinations, but the relief ruptures were found to vary depending upon the overall mechanics of the traumatic forces involved in the simulation experiments performed on the cadavers. The anti-shock ruptures were formed during shock trauma, and shockproof ruptures were not seen in cases of underlying compressive forces. The morphogenetic characterization of the relief rupture surface of the liver was also delineated in relation to its surface orientation to the spine on the basis of the terms "large" and "very large" depicting the quantum of force/s delivered out of an impact or blow.

Keywords: Abdomen; Blunt trauma; Cadaveric simulation; Contre coup injuries; Forensic examination; Liver rupture.