Stent graft as a bridge to allograft to treat a septic thoracic aortic pseudoaneurysm after spinal fusion

Abstract

A 29-year-old woman was admitted to our institution for severe septic syndrome. Her medical history included a T6-T8 posterior spinal fusion 7 years earlier for tuberculous spondylodiscitis. Contrast-enhanced computed tomography (CT) revealed a 70- × 58-mm pseudoaneurysm of the descending thoracic aorta extending from T6 to T8 level, surrounding the left T6 screw (A/Cover). A T6-T8 spondylodiscitis and bilateral paraspinal collections were also observed. Blood and T7 bone biopsy specimens grew Escherichia coli. To prevent an imminent pseudoaneurysm rupture and to allow cryopreserved aortic allograft (CAA) delivery, the patient first underwent conformable TAG 26- × 26- × 100-mm (W. L. Gore & Associates, Flagstaff, Ariz) thoracic aortic stent graft implantation under general anesthesia through a small left femoral incision. The procedure was uncomplicated. Exclusion of the pseudoaneurysm was assessed by final angiography and postoperative CT scan (B). Five days later, T2-T10 spinal fusion was conducted after infected hardware removal through a posterior approach along with drainage of the paraspinal collections. Aortic replacement using a 10-cm-long thoracic CAA was performed through a left posterolateral thoracotomy in the same operative course. A partial cardiopulmonary bypass at normothermia was established through a left femoral incision. An arterial perfusion cannula was positioned in the abdominal aorta and a venous cannula to the right atrium. During aortic replacement, a fistula was observed at the bottom of the aortic pseudoaneurysm communicating with the former location of the left T6 screw. The final step consisted of implantation in the vertebral defect of a titanium mesh cage containing autologous bone graft. Transdiaphragmatic epiploplasty was performed to isolate the CAA (C). The culture specimens of the removed orthopedic hardware and stent graft grew E. coli. Antibiotic treatment initially consisted of intravenous administration of cefotaxime and gentamycin switched postoperatively to intravenous administration of ceftriaxone for 12 weeks. Follow-up included visits at 1 month and 6 months postoperatively, and follow-up should be continued twice a year. Six months postoperatively, the patient was asymptomatic. The CT scan showed satisfactory coverage of the allograft by the omentum and the absence of allograft pseudoaneurysm or residual collection (D). Vascular injury after spinal instrumentation is a rare but life-threatening condition. Treatment of such injuries is not standardized. Previous studies have reported the use of stent grafts with good outcomes.1Zerati A.E. Leiderman D.B. Teixeira W.G. Narazaki D.K. Cristante A.F. Wolosker N. et al.Endovascular treatment of late aortic erosive lesion by pedicle screw without screw removal: case report and literature review.Ann Vasc Surg. 2017; 39: 285.e17-285.e21Abstract Full Text Full Text PDF Scopus (5) Google Scholar In our case, we believed that simple endovascular treatment was not possible because of the high risk of stent graft infection. We believed that CAA represented the best option in a septic field, as is the case with aortic graft infections.2Corvera J.S. Blitzer D. Copeland H. Murphy D. Hess Jr., P.J. Pillai S.T. et al.Repair of thoracic and thoracoabdominal mycotic aneurysms and infected aortic grafts using allograft.Ann Thorac Surg. 2018; 106: 1129-1135Abstract Full Text Full Text PDF PubMed Scopus (16) Google Scholar Potential postoperative CAA pseudoaneurysm formation requires close and lifelong follow-up. The patient consented to the use of related medical history and images for educational purposes.