Spinal cord stimulation and cerebral haemodynamics.

An increase of regional cerebral blood flow (rCBF) has been shown to occur in man during spinal cord stimulation (SCS) by Hosobuchi (1986) and by Meglio et al. (1988) using the 133-Xenon wash-out technique. In this paper we report the effects of SCS on CBF as measured by two different techniques: 8 patients were studied with the 133-Xe method and 28 with the transcranial doppler sonography (TCD), in two cases both studies were performed. The aim of our study was to: 1-verify the effect of SCS on CBF, 2-compare observations made by two different methods, and 3-evaluate a possible correlation between the stimulated spinal segmental level and the modification of CBF. The results of our study confirm that SCS interacts with the mechanisms of regulation of CBF. The stimulation of different spinal cord levels in the same patient can produce different effects and such effects are reproducible. An increase of CBF is more likely to occur with the stimulation of the cervical spinal cord. In patients studied by both methods the sign of CBF changes induced by SCS was the same. Finally, in two patients the effect of SCS on CO2 autoregulation was studied with TCD. The results of such a study, although preliminary, suggest that CO2 and SCS have a competitive effect upon the mechanisms of regulation of CBF.