Spondylitis transmitted from infected aortic grafts: a review

Abstract

Graft infection following aortic aneurysms repair is an uncommon but devastating complication; its incidence ranges from <1% to 6% (mean 4%), with an associated perioperative and overall mortality of 12% and 17.5-20%, respectively. The most common causative organisms are Staphylococcus aureus and Escherichia coli; causative bacteria typically arise from the skin or gastrointestinal tract. The pathogenetic mechanisms of aortic graft infections are mainly breaks in sterile technique during its implantation, superinfection during bacteremia from a variety of sources, severe intraperitoneal or retroperitoneal inflammation, inoculation of bacteria during postoperative percutaneous interventions to manage various types of endoleaks, and external injury of the vascular graft. Mechanical forces in direct relation to the device were implicated in fistula formation in 35% of cases of graft infection. Partial rupture and graft migration leading to gradual erosion of the bowel wall and aortoenteric fistulas have been reported in 30.8% of cases. Rarely, infection via continuous tissues may affect the spine, resulting in spondylitis. Even though graft explantation and surgical debridement is usually the preferred course of action, comorbidities and increased perioperative risk may preclude patients from surgery and endorse a conservative approach as the treatment of choice. In contrast, conservative treatment is the treatment of choice for spondylitis; surgery may be indicated in approximately 8.5% of patients with neural compression or excessive spinal infection. To enhance the literature, we searched the related literature for published studies on continuous spondylitis from infected endovascular grafts aiming to summarize the pathogenesis and diagnosis, and to discuss the treatment and outcome of the patients with these rare and complex infections.

Keywords: Aortic endograft; Continuous spondylitis.; Endovascular aneurysm repair; Vascular graft.

Figure 1

A 93-year-old man presented with low back and right leg pain, malaise and low-grade fever of 4 month duration; he had an abdominal aortic aneurysm treated with vascular graft 18 years before. Axial T1-weighted MR image of the lumbar spine shows pathological signal intensity of the L3 vertebral body, and continuous abnormal soft tissue of similar signal intensity extending from the posterior aneurysmal sac to L3 vertebral body (arrows). The aortic lumen is irregular, with flame-shaped areas of pointing contrast suggesting inflammatory infiltration into the aortic wall. With the presumptive diagnosis of infection, he was treated by his local physicians with antibiotics (ciprofloxacin and rifampicin) and analgesics, in addition to lumbar spine immobilization with a brace. CT-guided biopsy was done at his admission; cultures were negative, probably because of antibiotics administration. Because of deteriorated general health status, a joint decision was obtained for conservative treatment with long term suppression with antibiotics. Four months later, the patient is afebrile with improved but constant low back pain.