Intraspinal Pressure is Not Elevated After Traumatic Spinal Cord Injury in a Porcine Model Sham-Controlled Trial

It has been suggested that intraspinal pressure (ISP) below the dura is elevated following traumatic spinal cord injury (TSCI). The dura can maintain the pressure, and hence a subdural compartment syndrome has been hypothesized to develop regardless of bony decompression. This study aimed to evaluate whether a such intradural compartment syndrome develops during the first 72 h in a porcine TSCI model. First, in a randomized sham controlled-trial design, longitudinal ISP measurements were performed over a period of 72 h from onset of TSCI. TSCI was inflicted by a weight-drop contusion regime: 75-g rod, 75-mm free fall, and 5-min compression of the spinal cord. Second, in a sham-controlled dose-response design longitudinal ISP measurements were performed over a period of 16 h from the onset of TSCI, using two other contusion regimes: 75-g rod, 125-mm free fall, and 5-min compression; and 75-g rod, 75-mm free fall, and 240-min compression. Animals were kept sedated for the entire course of the study using propofol, fentanyl, and midazolam. Intraspinal pressure increased in TSCI and sham animals alike, but we found no significant increases in ISP following TSCI compared with the sham group, and we found no relationship between the ISP increase and larger impacts or increased time of compression. These findings suggest that the subdural swelling of the spinal cord following thoracic TSCI is not responsible for the ISP increase measured in our TSCI model, but that the ISP increase was caused by the surgical procedure or the reconstitution of normal cerebrospinal fluid pressure.