Biomechanical analysis of traumatic mesenteric avulsion

Area of Science:

• Biomechanics
• Trauma research
• Materials science

Background:

• Mesenteric avulsion injuries often result from high-deceleration events like road accidents.
• Seat belt restraints, while protective, may paradoxically increase the risk of mesenteric and bowel injuries.
• Understanding the biomechanical behavior of mesenteric and small bowel (MSB) tissues is crucial for injury prevention.

Purpose of the Study:

• To investigate the biomechanical properties of porcine mesentery and small bowel (MSB) tissue samples under dynamic loading conditions.
• To compare the mechanical behavior of intact MSB with isolated mesenteric and small bowel tissues.
• To establish a failure criteria for MSB tissue under varying strain rates.

Main Methods:

• Tensile tests were performed on fresh porcine MSB specimens using a dedicated test bench.
• Tests were conducted under both quasi-static (1 mm/s) and dynamic (100 mm/s) loading rates.
• Mechanical properties including stiffness and ultimate force were measured and compared.

Main Results:

• MSB tissue exhibited significant sensitivity to loading rate for both stiffness and ultimate force.
• Stiffness increased from 1.0 ± 0.2 N/mm at 1 mm/s to 1.3 ± 0.3 N/mm at 100 mm/s (p = 0.001).
• Ultimate force increased from 22 ± 5 N at 1 mm/s to 35 ± 8 N at 100 mm/s (p = 0.001), while displacement at failure was not rate-dependent.

Conclusions:

• MSB tissue failure appears to be governed by strain level rather than strain rate.
• These findings can inform the development of refined finite element models for injury analysis.
• Results may aid in investigating injury mechanisms related to seat belt restraints and improving protective devices.