Spinal cord injury after thoracic endovascular aortic aneurysm repair

Abstract

Purpose: Thoracic endovascular aortic aneurysm repair (TEVAR) has become a mainstay of therapy for aneurysms and other disorders of the thoracic aorta. The purpose of this narrative review article is to summarize the current literature on the risk factors for and pathophysiology of spinal cord injury (SCI) following TEVAR, and to discuss various intraoperative monitoring and treatment strategies.

Source: The articles considered in this review were identified through PubMed using the following search terms: thoracic aortic aneurysm, TEVAR, paralysis+TEVAR, risk factors+TEVAR, spinal cord ischemia+TEVAR, neuromonitoring+thoracic aortic aneurysm, spinal drain, cerebrospinal fluid drainage, treatment of spinal cord ischemia.

Principal findings: Spinal cord injury continues to be a challenging complication after TEVAR. Its incidence after TEVAR is not significantly reduced when compared with open thoracoabdominal aortic aneurysm repair. Nevertheless, compared with open procedures, delayed paralysis/paresis is the predominant presentation of SCI after TEVAR. The pathophysiology of SCI is complex and not fully understood, though the evolving concept of the importance of the spinal cord's collateral blood supply network and its imbalance after TEVAR is emerging as a leading factor in the development of SCI. Cerebrospinal fluid drainage, optimal blood pressure management, and newer surgical techniques are important components of the most up-to-date strategies for spinal cord protection.

Conclusion: Further experimental and clinical research is needed to aid in the discovery of novel neuroprotective strategies for the protection and treatment of SCI following TEVAR.

Figure 5. Surgical options for left subclavian artery management during TEVAR

When the operative plan requires covering the origin of the left subclavian artery (LSA), the LSA can be left without revascularization, or can be perfused through extra-anatomical surgical procedures, or more recently, by endovascular techniques. Surgical revascularization is either done routinely or only for selected patients.

Figure 6. Chimney graft technique for left subclavian artery revascularization

A thoracic aortic endograft is excluding a descending thoracic aneurysm and covering the origin of the left subclavian artery (LSA); a chimney graft is inserted in the LSA parallel to the proximal wall of the aortic stent. The top left figure shows a cross section of the aortic arch with the proximal end of the thoracic aortic stent and the LSA chimney graft in place. The bottom left figure shows a cross section of the distal portion of the aortic stent sealing the descending thoracic aorta. LSA: Left subclavian Artery; L: left

Figure 7. Periscope graft for left subclavian artery revascularization

A thoracic aortic endograft is excluding a descending thoracic aneurysm and covering the origin of the left subclavian artery (LSA); a periscope graft is inserted in the LSA through the distal part of the aorta. The top left figure shows a cross section of the aortic arch sealed with the proximal end of the aortic stent. The bottom left figure shows a cross section of the descending thoracic aorta with the thoracic stent and LSA periscope graft in place. LSA: Left subclavian Artery; L: left

Figure 8. Periscope Sandwich technique for left subclavian artery revascularization

Two thoracic aortic endograft are excluding a descending thoracic aneurysm with the proximal stent covering the origin of the left subclavian artery (LSA); A sandwich graft is inserted between two aortic stents. The top left figure shows a cross section of the aortic arch sealed with the proximal end of the aortic stent. The bottom left figure shows a cross section of the overlapping thoracic stents with the distal end of the sandwich graft between them. LSA: Left subclavian Artery; L: left