Neurosurgery
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Dorsal column stimulation (DCS) increases blood flow to the extremities and may produce a limb-saving effect in addition to treatment of refractory chronic pain in patients with peripheral vascular disease. The purpose of this study was to examine the importance of nitric oxide in cutaneous vasodilation caused by DCS. ⋯ Our results demonstrated that nitric oxide played a significant role in producing the DCS-induced increase in rat cutaneous hindpaw blood flow. The involvement of nitric oxide does not require the presence of autonomic efferent function; however, ganglionic blockade may unmask a mechanism for vasodilation during DCS that is independent of nitric oxide release.
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Case Reports
Cerebral hemodynamic and metabolic changes caused by brain retraction after aneurysmal subarachnoid hemorrhage.
The cerebral hemodynamic and metabolic effects of aneurysmal subarachnoid hemorrhage are complex. To investigate the impact of surgical retraction, we analyzed position emission tomography (PET) studies that measured the regional cerebral metabolic rate for oxygen, regional oxygen extraction fraction, and regional cerebral blood flow in four patients before and after right frontotemporal craniotomies for clipping of ruptured anterior circulation aneurysms. ⋯ This reduction in the cerebral metabolic rate of oxygen and the oxygen extraction fraction indicates a primary reduction in metabolism and uncoupling of flow and metabolism (luxury perfusion). Similar findings of luxury perfusion have been reported after ischemic stroke and traumatic brain injury. Further studies will be necessary to fully understand the clinical and pathophysiological significance of these observations.