OBJECTIVE: This study was undertaken to evaluate the use of somatosensory-evokedpotential (SSEP) monitoring on intercostal artery reimplantation (IAR) and spinal cord ischemia rates during thoracoabdominal ortic aneurysm repair. METHODS: Fifty-two patients had thoracoabdominal aortic aneurysm repair with IAR under SSEP guidance and 79 patients had repair with routine IAR without SSEP guidance from 1999 to 2010. RESULTS: No differences were observed between the two groups in age (63.1 ± 11.6 vs 64.8 ± 9.8 years), sex (57.7% vs 50.6% men), chronic dissections (40.4% vs 44.3%), renal insufficiency (11.5% vs 10.1%), and Crawford type 1 and 2 aneurysms (53.9% vs 53.9%). There was one case (1.9%) of immediate paraplegia and one case (1.9%) of delayed paraplegia in the SSEP group versus 2 cases (2.5%) of immediate paraplegia in the non-SSEP group (P = 0.92). In the SSEP group, 38 patients (73.1%) had SSEP changes, but only 15 (28.8%) required reimplantation. There were fewer IARs in the SSEP group compared with the non-SSEP group (28.8% vs. 59.5%, P = 0.004). No difference was observed in 30-day mortality between the SSEP and the non-SSEP group (3.9% vs. 7.6%, P = 0.48). CONCLUSIONS: The use of SSEP monitoring led to a significant decrease in the need for IAR without increasing the paraplegia rate.