[Aneurysms of the superior mesenteric artery]

Splanchnic arteries aneurysmatic pathology is rare, even if, in the last decades it has been noticed an increase of its incidence, owing to the worldwide use of the recent diagnostic tools as echography, TC, MR and angiography. Among visceral aneurysms those of the superior mesenteric artery (SMA) range the 5.5-8%. In the majority of cases SMA aneurysms are of mycotic etiology (60%), of atherosclerotic ones are less frequent, even if their incidence has increased in the last decades. Other causes are exceptional. Dimensions are generally moderate (1-3 cm.), yet aneurysms of a significant diameter, ranging from 4 to 8 cm., are reported in the most recent literature. Aneurysms can be symptomatic with abdominal upper quadrants pain, due to the compressive mass effect on the contiguous structures. In some cases typical signs of claudication abdominis are present. A pulsating epi-mesogastric abdominal mass is present in the 50% of subjects. In the 20% of the cases the patients come to medical attention presenting a situation of hemorrhagic shock for aneurysmatic rupture in the peritoneal cavity, or in the digestive tract, considering also the possibility of a thrombosis with consequent acute bowel ischemia. Urgent surgical operations, when possible, imply an high mortality rate. For these reasons, there is indication of elective surgery for all SMA aneurysms, both symptomatic and of occasional finding. The performable surgical techniques are: proximal and distal ligation, with or without aneurysmectomy, that is the most utilized because commonly performed during emergency operations. This technique requires the presence of a sufficient collateral vascular supply. Endoaneurysmorraphy can be performed only in the case of mild-dimension saccular aneurysms. Revascularization techniques through substitution or by-pass are mandatory in managing voluminous mass aneurysms. It is reported a case of SMA aneurysm of exceptional dimensions (diameter approximatively 10 cm.) that for its enormous volume substituted completely the mesenteric axis, involving the origin of the jejuno-ileal and ileo-colic branches. In this case it has been mandatory the performing of the aorto-mesenteric by-pass technique, distally patch modelled and sutured to the residual posterior SMA wall, on the purpose to allow the revascularization of the emerging jejunal arteries and adapted to the residual distal stump to irrorate ileo-colic branches.