Background and Significance
Surgery for aortic aneurysms has made significant progress in the past decade, with a marked fall in both morbidity and mortality. The major remaining problems concern therapy for extensive thoracoabdominal aneurysms (TAA/A), whose current treatment involves high-risk surgery in a frail, elderly population, including the frightening threat of postoperative paraplegia. Although acceptable rates of adverse outcome for TAA/A resection at aortic surgery centers in highly selected patients have been reported, nationwide estimates of hospital mortality exceed 20%. In consequence of the high morbidity of open surgical repair, the vast majority of patients with TAA/A currently are never referred for elective treatment, and the results of emergency surgery are so dismal that some centers refuse to undertake these operations in elderly patients. The possibility of treatment of extensive TAA/A by endovascular techniques thus has enormous potential benefits. But before endovascular therapy for extensive TAA/A can become a reality, more reliable spinal cord protection must be guaranteed. Despite claims by some of its advocates to the contrary, endovascular repair of these aneurysms involves a risk of paraplegia as high or higher than open surgical treatment by experienced surgeons. To devise strategies to minimize this risk will require a thorough understanding of the physiology of normal spinal cord perfusion, and of the response of the spinal cord circulation to the sudden occlusion of a large number of SAs. We have already begun such studies in the pig model, which has heretofore been very successful in leading from investigations of strategies for cerebral protection in the laboratory to the adoption of safer techniques in clinical practice.
Gabriele Di Luozzo, MD