Spinal Cord Protection of Aorto-Iliac Bypass in Open Repair of Extent II and III Thoracoabdominal Aortic Aneurysm.

Background: Spinal cord injury (SCI) is one of the serious complications of thoracoabdominal aortic aneurysm (TAAA) repair. Cardiopulmonary bypass (CPB) and left heart bypass (LHB) are well-established extracorporeal circulatory assistance methods to increase distal aortic perfusion and prevent spinal cord ischaemia in TAAA repair. Aorto-iliac bypass, a new surgical adjunct offering distal aortic perfusion without the need of complex perfusion skills, was developed as a substitute for CPB and LHB. However, its spinal cord protective effect is unknown.

Methods: The perioperative data of 183 patients who had elective open Crawford extent II and III TAAA repair at our aortic centre from July 2011 to May 2019 were retrospectively analysed. Spinal cord protection was compared between the aorto-iliac bypass group (n=106) and the extracorporeal circulatory assistance group (n=77 [65 CPB, 12 LHB]), and the risk factors for SCI in these patients were explored.

Results: Eleven (11) patients had postoperative SCI: five (6.5%) in the extracorporeal circulatory assistance group (four with CPB and one with LHB), and six (5.7%) in the aorto-iliac bypass group. The incidence of SCI was 6.0% (11/183 cases). There was no difference between the aorto-iliac bypass group and the extracorporeal circulatory assistance group (p=1.0), while operation time, proximal aortic clamp time, intercostal artery clamp time, and length of intensive care unit stay were all increased in the latter group. Multivariate logistic regression analysis showed that cerebrospinal fluid pressure (odds ratio [OR] 1.270; 95% confidence interval [CI] 1.092-1.478 [p=0.002]) and lowest haemoglobin on the first postoperative day (OR 0.610; 95% CI 0.416-0.895 [p=0.011]) were the independent predictors of SCI in TAAA repair.

Conclusions: Spinal cord protection of aorto-iliac bypass is comparable to that of CPB and LHB in open TAAA repair.