Effect of electrical stimulation of the cervical spinal cord on blood flow following subarachnoid hemorrhage

Abstract

Cervical spinal cord stimulation (SCS) increases global cerebral blood flow (CBF) and ameliorates cerebral ischemia according to a number of experimental models as well as some anecdotal reports in humans. Nonetheless, such stimulation has not been systematically applied for use in cerebral vasospasm. In the present study the authors examined the effect of cervical SCS on cerebral vasoconstriction in a double-hemorrhage model in rats. Subarachnoid hemorrhage (SAH) was induced with 2 blood injections through an indwelling catheter in the cisterna magna. Spinal cord stimulation was applied 90 minutes after induction of the second SAH (Day 0) or on Day 5 post-SAH. Measurements of the basilar artery (BA) diameter and cross-sectional area and regional CBF (using laser Doppler flowmetry and (14)C-radiolabeled N-isopropyl-p-iodoamphetamine hydrochloride) were obtained and compared between SAH and sham-operated control rats that did not receive SCS. At Day 0 after SAH, there were slight nonsignificant decreases in BA diameter and cross-sectional area (89 +/- 3% and 81 +/- 4%, respectively, of that in controls) in no-SCS rats. At this time point, BA diameter and crosssectional area were slightly increased (116 +/- 6% and 132 +/- 9%, respectively, compared with controls, p < 0.001) in SCS-treated rats. On Day 5 after SAH, no-SCS rats had marked decreases in BA diameter and cross-sectional area (64 +/- 3% and 39 +/- 4%, respectively, compared with controls, p < 0.001) and corrugation of the vessel wall. These changes were reversed in rats that had received SCS (diameter, 110 +/- 9% of controls; area, 106 +/- 4% of controls; p < 0.001). Subarachnoid hemorrhage reduced CBF at Days 0 and 5 post-SAH, and SCS increased flows at both time points, particularly in regions supplied by the middle cerebral artery. Data in this study showed that SCS can reverse BA constriction and improve global CBF in this SAH model. Spinal cord stimulation may represent a useful adjunct in the treatment of vasospasm.