Investigation of tissue level tolerance for cerebral contusion in a controlled cortical impact porcine model

Abstract

Objective

Cerebral contusions (CC) represent a frequent lesion in traumatic brain injury, with potential morbidity from mass effect and tissue loss. Better understanding of the mechanical etiology will help to improve head protection. The goal of this study is to investigate the threshold for mechanical impact parameters to induce CC in an in vivo porcine controlled cortical impact model.

Methods

Thirty-four adult male pigs underwent craniotomy and controlled cortical impact with a hemispherical tip on intact dura under general anesthesia. Peak impact depth varied between 1.1 and 12.6 mm, and impact velocity between 0.4 and 2.2 m/s while the dwell time was kept at 200 ms. Two days following impact, the animals underwent magnetic resonance (MR) imaging of the brain, and were subsequently sacrificed for brain extraction. CC damage was investigated by magnetic resonance imaging and histology.

Results

All animals recovered from the impact without overt neurological deficit. Provoked injuries were histologically confirmed to be CC. Decreasing probability of cortical damage and white matter edema volume was observed with decreasing impact depth and velocity. No CC could be demonstrated below a product of impact depth and velocity of 0.8 mm*m/s, whereas the probability for CC was one third below 15 mm*m/s. The threshold for CC development as estimated from the current series of experiments, was situated at an impact depth of 2.0 mm and impact velocity of 0.4 m/s

Conclusion

Mechanical thresholds for CC development could be explored in the current porcine controlled cortical impact model. Findings will be used to further refine a cerebral contusion porcine model with volumetric histology data in light of future finite element cerebral contusion validation studies.

Keywords:

• Cerebral contusion
• controlled cortical impact
• traumatic brain injury
• porcine model

Disclosure statement

None of the authors have competing financial interests regarding the content of this paper.

Data availability statement

The authors agree to share their source data upon request.

Additional information

Funding

This research was funded by KULeuven grant OT/12/071 and FWO grant G.0C67.13. We wish to acknowledge Stephanie De Vleeschauwer, Dr Kris Meurrens (Animal Research Center, KULeuven), Marc Verbeek (Medical Technical Services, KULeuven), Piet Claus (Cardiovascular Imaging, KULeuven), Ronald Peeters, Walter Coudyzer (Radiology, University Hospitals Leuven) and An Van Damme (UCLouvain).