Reduction of neurologic injury after high-risk thoracoabdominal aortic operation

Of all aortic operations, thoracoabdominal aortic repairs have the highest risk of spinal cord neurologic injury, manifest by lower limb paraplegia or paraparesis. Cerebrospinal fluid drainage combined with intrathecal papaverine (CSFDr + IP) may reduce the risk and severity of neurologic injury. The objective of this study was to evaluate the effect of CSFDr + IP to prevent neurologic injury after high-risk thoracoabdominal aneurysm repairs.

We screened 64 patients before operation with descending thoracic or thoracoabdominal aneurysms for possible inclusion in a prospective, randomized study. Thirty-three patients with high-risk type I and II thoracoabdominal aneurysms met inclusion criteria and 17 were randomly assigned to CSFDr + IP and 16 to the control group. The study was terminated early after interim analysis revealed a significant difference.

Of 64 patients screened, 2 patients died after operation (3.1%, 2/64); both were in the randomized study (6%, 2/33), and neither had a neurologic injury. Neurologic injury developed in 2 CSFDr + IP patients and 7 control patients (p = 0.0392). Control patients also had lower postoperative motor strength scores (p = 0.0340). On multivariate analysis, risk factors for neurologic injury included (p < 0.05) longer cross-clamp time, failure to actively cool with bypass, and postoperative hypotension, whereas CSFDr + IP was protective. Logistic regression showed that CSFDr + IP and active cooling significantly reduced the risk of injury and that the two combined modalities were additive. Of 64 patients screened, only 2 (3%) had a permanent neurologic deficit preventing ambulation.

For high-risk thoracoabdominal aneurysms, CSFDr + IP was effective in reducing the incidence and severity of neurologic injury. Active cooling may be further additive to CSFDr + IP protection, although this needs to be confirmed in a larger study.