Porcine blast injury model achieves prolonged elevation of intra-compartmental pressures without exogenous pressure manipulation

Background: Most existing animal models of acute compartment syndrome (ACS) rely on exogenous manipulation of intra-compartmental pressures to model ACS. The purpose of the current study was to evaluate the endogenous effect of a blast injury on porcine lower leg intra-compartmental pressures (ICP).

Methods: The hindlimb of juvenile Landrace pigs was fractured at the diaphyseal tibia and subjected to blasts of compressed air to mimic a blast injury. Injured and control legs underwent pre-operative continuous ICP monitoring. At 4.5 h post injury, the fracture was stabilized followed by closure of the anterior compartment fascia (continued compartment pressure model, CCPM) or four compartment fasciotomy. Pressure measurements were made after operative fixation. Select pigs in CCPM were harvested between 48 and 72 h post-injury to evaluate the duration of ICP elevation.

Results: Post-injury, the model created significantly elevated ICP compared to control limbs (54.5 ± 18.2 vs. 18.2 ± 4.9 mmHg; p < 0.001). Operative fixation and anterior compartment fascial closure further increased the ICP (Mean: 87.4 ± 42.5 mmHg) relative to the pre-operative state (p = 0.037). Fasciotomy returned baseline compartment pressures (Mean: 13.7 ± 10.2 mmHg) which were equivalent to control limbs (p = 0.117). Pressure measurements at the time of delayed harvest (48-72 h) demonstrated that elevated ICP persisted following injury (69.7 ± 55.12 mmHg).

Conclusion: The current study demonstrates that a pilot porcine blast model elevates ICP comparable to existing animal models of compartment syndrome without exogenous ICP manipulation. ICP remained elevated at 48-72 h in the absence of fasciotomy.