Cold blood spinoplegia under motor-evoked potential monitoring during thoracic aortic surgery
Shinya Takahashi1, Kazumasa Orihashi, Katsuhiko Imai
1Department of Cardiovascular Surgery, Hiroshima University Hospital, Hiroshima, Japan. shiny@mte.biglobe.ne.jp
Objective:
Motor-evoked potential monitoring is used to prevent paraplegia during thoracic aortic surgery. Multidetector computed tomography has been used preoperatively to detect the Adamkiewicz artery, but the hemodynamic significance of the Adamkiewicz artery is controversial. This study aims to evaluate whether the multidetector computed tomography-defined Adamkiewicz artery is hemodynamically essential and needs to be reconstructed with cold blood spinoplegia under motor-evoked potential monitoring.
Methods:
From 2005 to 2008, both preoperative multidetector computed tomographic analysis and intraoperative neurogenic motor-evoked potential monitoring with cold blood infusion into the clamped segment of the aorta were done in 15 patients. A motor-evoked potential decrease to less than 50% of the initial value at 3 minutes after cold blood infusion determined the hemodynamic significance of the multidetector computed tomography-defined Adamkiewicz artery. Adamkiewicz arteries determined to be essential were reconstructed, and those determined to be nonessential were sacrificed.
Results:
The Adamkiewicz artery was involved in the clamped segment of the aorta in 11 cases. After cold blood infusion, 8 patients experienced no significant motor-evoked potential decrease, and Adamkiewicz artery ligation was undertaken, whereas a moderate motor-evoked potential decrease was noted in 1 patient, prompting reconstruction. None of these 9 patients had permanent neurologic deficits. In 2 patients, the Adamkiewicz artery was reconstructed based on motor-evoked potential findings, with paraparesis occurring in 1 patient. In 4 patients without Adamkiewicz artery involvement in the clamped segment, there was no neurologic deficit.
Conclusions:
Cold blood infusion accelerates motor-evoked potential changes and might enable decision making regarding the need for reconstruction of multidetector computed tomography-defined Adamkiewicz arteries. Cold blood-loaded motor-evoked potential is beneficial to minimize Adamkiewicz artery reconstruction time and limit spinal cord ischemia.
