4.2. Controlled Cortical Impact TBI Model

A well-established CCI TBI piglet model [6,53,56], as shown in Figure 1, was used to produce focal cortical contusion utilizing a validated skull-mounted, spring-loaded blunt indentation device to create a rapid (4 ms) displacement of the cortical surface with no inertial motion of the head. This injury mechanism produces focal contusion, with underlying white matter damage, decreased cerebral blood flow (CBF) and somatosensory dysfunction. As previously described [6,53,56], a craniectomy, 1 cm larger than the indentor tip, was performed on the right coronal suture of the animal under anesthesia and the dura was opened to expose the cortical surface. Then the indentation device was firmly attached to the skull with screw fixation and the spring-loaded indentor tip was ejected over 4 msec to a depth of 0.7 cm of the cortical rostral gyrus and then removed. The cortical surface was irrigated, the dura was reapproximated, and the scalp was sutured closed and sealed with Dermabond. Immediately after the injury procedure, animals were recovered from anesthesia and extubated when animals met the following criteria: return of pinch reflex; spontaneously breathing and able to maintain oxygenation and ventilation; normotensive; stable heart and respiratory rates. After extubation, animals were returned to the animal housing facility when they met the following criteria: vocalization without squealing, steady ambulation, no aggression or avoidance behavior, no piloerection, and proper feeding and drinking behaviors [6,53,56].