gms | German Medical Science

Objective: Repair of aortic aneurysm is associated with risk of spinal cord ischemia and thus paralysis due to loss of segmental artery. Continuous intraoperative monitoring of spinal cord function allows immediate reaction to the interpretation of signals and subsequently decreases risk of spinal cord ischemia during aortic aneurysm surgery. Therefore use of SSEP and MEP is standard procedure when repairing thoracic and thoracoabdominal aortic aneurysm. We report our experience with neuromonitoring-guided thoracoabdominal aortic aneurysm repair performed by the Department of Vascular Surgery.

Method: Between 2013 and 2014 five open surgical repairs of aortic aneurysm with high risk of spinal cord ischemia and use of distal aortic perfusion with extracorporal oxygenation were performed. We conducted intraoperative SSEP and MEP. In response to change in signals immediate intraoperative maneuvers, including elevating distal perfusion pressure, drainage of cerebrospinal fluid and segmental artery reimplantation, were done. All surgeries were performed by the same surgeon, anesthesiologist and neurosurgeon responsible for neuromonitoring.

Results: Neuromonitoring was technically stable and successful in all patients. There was no immediate clinically noticeable spinal cord ischemia in all five patients. One patient showed loss of MEP greater 50% instantaneous after aortic cross clamping. Increasing distal aortic pressure did not restore potentials, but potentials returned after reimplantation of segmental artery. This patient showed no deficit postoperatively. One patient suffered from late onset paraparesis, intraoperatively there were stable findings of MEP and SSEP. As the patient suffered from severe abdominal complications in the further course this was considered as critical illness neuropathy. All patients achieved adequate readings of SSEP.

Conclusions: Neuromonitoring, especially MEP, is a reliable and essential technique to evaluate on site function of spinal cord during repair of aortic aneurysm. Normal SSEP and MEP readings have a reliable negative predictive value. The isochronic on-site assessment of spinal cord function by evoked potentials is the most important way to prevent spinal cord ischemia in repair of aortic aneurysm.