4.1. TNS Efficacy on Cerebral Vasospasm
microthrombi, hypoxic injury, vasospasm, neurobehavioral deficits, aneurysmal SAH, DCI
DCI, VASOSPASM
The results of this study did not show a significant difference in DCI occurrence between patients who received TNS (7/30, 23%) and sham (8/30, 27%). External stimulation of the trigeminal nerve compared to sham stimulation does not appear to decrease vasospasm-related DCI in patients with aneurysmal SAH. No significant difference between the two groups was observed regarding the functional outcome, or regarding EQ5D-3L measurements of health-related quality of life, after 6 months.These initial clinical results in humans contradict the conclusions raised in previous works. An experimental study on pigs found that TNS increased arterial lumen diameters and cerebrospinal fluid CGRP (calcitonin gene-related peptide) levels, and decreased microthrombi and ischemia-induced hypoxic injury, as well as neurobehavioral deficits [To our knowledge, this study is the first randomized control trial to have tested this hypothesis. The lack of positive results might be attributed to DCI mechanisms that are not yet fully understood. A pathological decrease in cerebral autoregulation during vasospasm has been hypothesized, which could explain the stronger regulation of cerebral perfusion and euphemizing treatment effects [