TP1-6 Pathological patterns of spinal cord blood flow after injury visualised with laser speckle contrast imaging

ObjectivesIn humans the effect of spinal cord injury (SCI) on spinal cord blood flow (SCBF) is poorly understood. We imaged SCBF intraoperatively using laser speckle contrast imaging (LSCI).MethodsWe recruited 4 patients without SCI and 22 patients with SCI. Inclusion criteria for SCI patients are: AIS A–C, 18–70 years old, surgery within 72 hour of injury. In the SCI patients, we monitored spinal cord perfusion pressure and microdialysis from the injury site for 24 hour postoperatively. Mean patient follow-up after SCI was 7 m.ResultsLSCI signal is dampened by cerebrospinal fluid, but not dura. In patients without SCI we observed intact autoregulation, as well as SCBF variation with cardiac cycle, respiratory cycle and arterial pCO2. In SCI patients three pathological SCBF patterns were seen: necrosis-penumbra, patchy-perfusion and hyper-perfusion. Increase in MAP (>20 mmHg) increased overall injury site SCBF, but in 5/22 SCI patients there was a local steal effect where SCBF increased in some regions but decreased in others. In 7 SCI patients there was diastolic ischaemia, with regions only perfused in systole, but not diastole. Low injury site SCBF correlated with low spinal cord perfusion pressure, low tissue glucose, high tissue lactate and less improvement in combined sensory AIS score at follow-up.ConclusionsLSCI can be used to visualise SCBF non-invasively with high spatial-temporal resolution. We observed pathological SCBF patterns after SCI and some unanticipated SCBF responses to blood pressure changes.