Inclusion Criteria:  Age ≥18 Undergoing high risk endovascular thoraco-abdominal aortic aneurysm repair, based on aortic coverage length:  2a: Extent I, II, III TAAA 2b: Extent IV TAAA with >5cm coverage above the celiac artery  Exclusion Criteria:  Active prison incarceration active pregnancy moribund patients ruptured aneurysm coagulopathy precluding CSF drain placement urgent or emergent aneurysm repairs