Temporal and Spatial Evolution of Raised Intraspinal Pressure after Traumatic Spinal Cord Injury

Traumatic spinal cord injury (SCI) often leads to permanent neurological impairment. Currently, the only clinically effective intervention for patients with acute SCI is surgical decompression by removal of impinging bone fragments within 24 h after injury. Recent clinical studies suggest that elevated intraparenchymal spinal pressure (ISP) limits functional recovery following SCI. Here, we report on the temporal and spatial patterns of elevated ISP following a moderate rodent contusion SCI. Compared with physiological ISP in the intact cord (2.7 ± 0.5 mm Hg), pressures increase threefold 30 min following injury (8.9 ± 1.1 mm Hg, p < 0.001) and remain elevated for up to 7 days (4.3 ± 0.8 mm Hg). Measurements of rostrocaudal ISP distribution reveal peak pressures in the injury center and in segments rostral to the injury during the acute phase(≤ 24 h). During the subacute phase(≥ 72 h), peak ISP decreases while a 7.5 mm long segment of moderately elevated ISP remains, centered on the initial contusion site. Interestingly, the contribution of the dural and pial compartments toward increased ISP changes with time after injury: Dural and pial linings contribute almost equally to increased ISP during the acute phase, whereas the dural lining is primarily responsible for elevated ISP during the subacute phase (78.9%). Our findings suggest that a rat contusion SCI model in combination with novel micro-catheters allows for direct measurement of ISP after SCI. Similarly to traumatic brain injury, raised tissue pressure is likely to have detrimental effects on spontaneous recovery following SCI.