An aortoenteric fistula (AEF) may be defined as a communication between the aorta and an adjacent loop of bowel. Depending on the underlying cause, a primary or secondary classification is assigned. A primary fistula arises without a previous history of aortic repair or intervention and typically results from erosion of an enlarged or infected native aorta into the anterior duodenum. A secondary fistula occurs after a vascular procedure and involves prosthetic graft material such as a suture line. Secondary fistulas occur more frequently and are recognized complications of prosthetic arterial grafts.

In more than half of primary AEF, aneurysmal dilation of the abdominal aorta with erosion or rupture into the adjacent overlying third and fourth portions of the retroperitoneal duodenum is most frequently encountered, although other sites of erosion have been found extending to adjacent loops of bowel. Fistulas resulting from primary infections of the aorta and subsequent rupture into the duodenum are the other major type of primary AEF. Tuberculosis, salmonella, syphilis, and mycotic species have all been reported to be causative organisms.<sup>38 Reckless J.P.D., McColl I., Taylor G.W. Aorto-enteric fistulae: An uncommon complication of abdominal aortic aneurysms Br J Surg 1972 ;  59 : 458-462  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Other sources for primary fistulas include gallstones, periaortic malignancies and metastases,<sup>1 Armitage N.C., Ballantyne R.C. Primary aortoduodenal fistula due to recurrent colorectal carcinoma. Report of a case Dis Colon Rectum 1990 ;  33 : 148-149  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 19 Geary S.R., Walworth E.Z. Aortoduodenal fistula secondary to metastatic carcinoma: Angiographic demonstration JAMA 1976 ;  235 : 2520-2521

Cliccare qui per andare alla sezione Riferimenti</sup> ulcers,<sup>46 Steffes B.C., O'Leary J.P. Primary aorticoduodenal fistula: A case report and review of the literature Am Surg 1980 ;  46 : 121-129

Cliccare qui per andare alla sezione Riferimenti</sup> diverticular and appendiceal abscesses,<sup>21 Grande J.P., Ackerman D.M., Edwards W.D. Aortoenteric fistulas Arch Pathol Lab Med 1989 ;  113 : 1271-1275

Cliccare qui per andare alla sezione Riferimenti</sup> radiation therapy,<sup>17 Estrada F.P., Tachovsky T.J., Orr R.M. , e al. Primary aortoduodenal fistula following radiotherapy Surg Gynecol Obstet 1983 ;  156 : 646-650

Cliccare qui per andare alla sezione Riferimenti</sup> cystic medial necrosis,<sup>41 Rhim J.A., Rubin R.A., Katzka D.A. , e al. Primary aortoduodenal fistula: A unique presentation of a pseudoaneurysm associated with cystic medial necrosis Am J Gastroenterol 1993 ;  88 : 447-450

Cliccare qui per andare alla sezione Riferimenti</sup> and swallowed foreign bodies.<sup>30 Moulton S., Adams M., Johansen K. Aortoenteric fistula: A 7-year urban experience Am J Surg 1986 ;  151 : 607-611  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup>

Secondary AEF develops between previously placed interposition aortic graft material and the adherent anterior duodenum, usually involving the proximal anastomosis. Presentation can be seen months to years following the original operation. Failure to separate the aortic prosthesis from overlying bowel, usually by closing the aneurysm shell and retroperitoneal tissue or interposing omentum, may increase the likelihood of this occurrence.<sup>26 Kleinman L.H., Towne J.B., Bernard V.M. A diagnostic and therapeutic approach to aortoenteric fistulas: Clinical experience with twenty patients Surgery 1979 ;  86 : 868-880

Cliccare qui per andare alla sezione Riferimenti</sup> Inadequate retroperitonealization at the time of graft implantation, redundant graft, emergency operations for ruptured aortic aneurysms, contamination with enteric contents, and the type of suture material used all have been reported to predispose to this condition.<sup>8 Busuttil R.W., Rees W., Wilson S.E. , e al. Pathogenesis of aortoduodenal fistula: Experimental and clinical correlates Surgery 1979 ;  85 : 1-12

Cliccare qui per andare alla sezione Riferimenti, 14 Donovan T.J., Bucknam C.A. Aortoenteric fistula Arch Surg 1967 ;  95 : 810-820

Cliccare qui per andare alla sezione Riferimenti, 16 Elliott J.P., Smith R.F., Szilagyi D.E. Aortoenteric and paraprosthetic-enteric fistulas Arch Surg 1974 ;  108 : 479-490

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