Cerebrospinal Fluid Drainage and Induced Hypertension Improve Spinal Cord Perfusion After Acute Spinal Cord Injury in Pigs

BACKGROUND:Acute spinal cord injury (SCI) is commonly treated by elevating the mean arterial pressure (MAP). Other potential interventions include cerebrospinal fluid drainage (CSFD).OBJECTIVE:To determine the efficacy of aggressive MAP elevation combined with intrathecal pressure (ITP) reduction; our primary objective was to improve spinal cord blood flow (SCBF) after SCI.METHODS:All 15 pigs underwent laminectomy. Study groups included control (n = 3); SCI only (n = 3); SCI combined with MAP elevation (SCI + MAP) (n = 3); SCI combined with CSFD (SCI + CSFD) (n = 3); and SCI combined with both MAP elevation and CSFD (SCI + MAP + CSFD) (n = 3). SCBF was measured with laser Doppler flowmetry.RESULTS:In the SCI group, SCBF decreased by 56% after SCI. MAP elevation after SCI resulted in a 34% decrease in SCBF, whereas CSFD resulted in a 59% decrease in SCBF. The combination of CSFD and MAP elevation resulted in a 24% increase in SCBF. The SCI + MAP group had an average ITP increase of 5.45 mm Hg after MAP elevation 1 hour after SCI and remained at that level throughout the experiment.CONCLUSION:Both MAP elevation alone and CSFD alone led to only short-term improvement of SCBF. The combination of MAP elevation and CSFD significantly and sustainably improved SCBF and spinal cord perfusion pressure. Although laser Doppler flowmetry can provide flow measurements to a tissue depth of only 1.5 mm, these results may represent pattern of blood flow changes in the entire spinal cord after injury.ABBREVIATIONS:CSFD, cerebrospinal fluid drainageITP, intrathecal pressureLDF, laser Doppler flowmetryMAP, mean arterial pressureSCBF, spinal cord blood flowSCI, spinal cord injury