Multiple factors predict the risk of spinal cord injury after the frozen elephant trunk technique for extended thoracic aortic disease

Abstract

OBJECTIVES: Spinal cord injury (SCI) after the frozen elephant trunk (FET) technique is more frequent than after endovascular aneurysm repair. This study aimed to identify risk factors of SCI after the FET technique. METHODS: We performed the FET technique for extended thoracic aortic disease in 224 patients (mean age, 72.1 ± 10.9 years) from September 1997 to December 2011. The patients included those with acute type A aortic dissection (n = 103), acute type B aortic dissection (n = 30), chronic type B aortic dissection (n = 11) and thoracic atherosclerotic aneurysm (n = 80). Cerebrospinal fluid drainage (CSFD) was preoperatively performed for 18 elective cases with a high risk of spinal cord ischaemia from January 2003. RESULTS: Postoperative SCI was present in 8 (3.5%), including complete paraplegia in 3, patients and transient or permanent paraparesis in 5 patients. CSFD was not a significant independent risk factor (P = 0.93) for SCI. Univariate logistic regression analysis identified pathology (P = 0.001), diabetes (P = 0.001), previous aortic operation (P = 0.003), atherosclerotic aorta (P = 0.003), distal position of the stent graft below the ninth thoracic vertebral level (Th9; P = 0.001) and low blood pressure after the operation (P = 0.009) as significant independent risk factors for SCI. Stepwise logistic regression analysis identified the distal position of the stent graft below Th9 (P = 0.003; odds ratio [OR], 15.167; 95% confidence interval [95% CI], 2.568-89.578), mean pressure <70 mmHg (P = 0.008; OR, 11.470; 95% CI, 1.920-68.546) and diabetes (P = 0.009; OR, 9.621; 95% CI, 1.779-52.032) as significant independent risk factors for SCI. CONCLUSIONS: There were multiple factors predicting the risk of SCI after the FET technique. Paraplegia may be prevented by avoiding deep insertion of the stent graft and by keeping blood pressure elevated after the operation.