DISCUSSION
In patients undergoing FET for chronic arch and/or descending aorta aneurysms SCI has been reported in up to 20% of cases4. Although CSFD has been a useful method to relieve paraplegia after repair of type B acute aortic dissection5, its role before, during and after surgery for extended aortic aneurysms has not yet been clearly defined. Indeed, there are still insufficient data to recommend the prophylactic use of CSFD when FET is performed to treat patients with thoracic aortic pathologies involving the aortic arch.
Katayama et al. reported postoperative SCI in 3.5% of patients undergoing FET mostly for acute aortic dissection preoperative CSFD being used in <10% of cases6; they concluded that paraplegia may be prevented by avoiding deep insertion of the stent graft and by maintaining an elevated blood pressure postoperatively. According to a recent meta-analysis, FET was associated to more adverse neurologic events in acute type A dissection while a significantly lower risk of SCI was related to the use of a stent of 10 cm indicating that a stent 15 cm or greater or coverage extending up or beyond T8 should be avoided7. On the other hand, analyzing patients undergoing FET for acute aortic dissection others found that the level of deployment of the distal edge of the stent graft did not influence development of post-repair paraplegia8.
In the present case pre-operative partial occlusion of intercostal branches due to intra-aortic thrombotic stratification may have resulted in chronic SCI. During surgery, temporary circulatory arrest and missed antegrade perfusion of the left subclavian artery may have worsened chronic SCI; nevertheless, during the procedure an evident subclavian artery backflow indicated adequate flow in the left vertebral artery while perfusion of the descending aorta was maintained with a catheter inserted into the graft with adequate perfusion pressures. Furthermore, post-operative CT scan showed a correct position of the short stent of the Thoraflex graft, which was inserted under direct vision verifying absence of intercostal branches in the covered thoracic aorta. The mild ischemia due to the surgical procedure associated to pre-existing chronic SCI may justify both the post-operative paraplegia and its rapid reversal with CSFD.
The present case confirms that CSFD can effectively reverse paraplegia after a FET procedure and that a successful outcome may be obtained by early awakening the patient for accurate assessment of the neurological status and timely detection of SCI. Furthermore, when using FET in atherosclerotic aortic aneurysms with diffuse thrombotic wall stratification it may be reasonable to consider the prophylactic use of CSFD.