Spinal cord ischemia in open and endovascular thoracoabdominal aortic aneurysm repair: new concepts

Abstract

For more than half a century ischemic spinal cord injury (SCI) and consecutively permanent paraplegia remained the most devastating complication after open and endovascular thoracoabdominal aortic aneurysm (TAAA) repair. Various neuroprotective strategies (e.g., motor-/somatosensory evoked potential monitoring and cerebrospinal fluid drainage) used as adjuncts have lowered the SCI; maybe most importantly, the modern collateral network (CN) has begun to replace the classic understanding of spinal cord blood supply implying several consequences. Reliable non-invasive tools to monitor cord perfusion to detect imminent spinal cord malperfusion, ischemia and forthcoming neurologic injury (particularly early postoperatively) is not available, neither is a reliable strategy to prevent ischemic injury during distal circulatory arrest and after segmental artery occlusion. Currently, two promising new concepts--potentially advancing spinal protection in open and endovascular TAAA repair--address these issues: 1) non-invasive real-time monitoring of the paraspinous CN-oxygenation via near-infrared spectroscopy (NIRS) as an alternative to the demanding direct neuromonitoring; and 2) preconditioning of the CN as minimally invasive, endovascular "first stage" to increase the resilience of spinal cord perfusion prior to definite aortic repair. This article illustrates both concepts discussing: 1) the clinical application of thoracic and lumbar collateral NIRS monitoring to indirectly detect spinal cord hypoperfusion; and 2) minimally invasive selective segmental artery coil-embolization (MISACE) for (arteriogenic) preconditioning of the CN prior to extensive open or endovascular staged TAAA repair.