Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3745_Библиотеки_им_академика_М_И_Перельмана

The larger of the two aneurysms was repaired surgically. The previous surgical incision was reopened and extended. A large false aneurysm was confirmed; the graft appeared to have become detached from the artery. There were no signs of infection. The aneurysm was replaced by straight 8-mm gelatine-coated woven

Arterial degeneration is the most common primary factor. The disease process that mandated the bypass continues after its insertion [1, 7, 8]. Histologically, a chronic inflammatory response can be identified at an anastomosis [9].

Anastomotic aneurysms can be caused by local infection. Infection with high-vir­ulence bacteria, such as Staphylococcus aureus, usually presents early with clinical graft infection. Late anastomotic rupture is often caused by low-virulence organisms, such as Staphylococcus epidermidis. Up to 30 per cent of anastomotic aneurysms can be shown to harbour pathogenic bacteria at reoperation [7]. This has implications for surgical repair (see below). [Q2: D, C, B, A, E]

Complications are related to aneurysm size. Therefore, conservative management may be undertaken if the aneurysm is small and easily accessible, and demonstrates no evidence of progressive enlargement or symptoms. Aneurysms less than 2 cm in diameter can be observed safely [1]. Above this size, the incidence of complications rises and surgical intervention should be considered. However, the medical state of the patient may necessitate selective aneurysms larger than 2 cm being managed conservatively by watchful waiting.

False aneurysms caused iatrogenically following direct arterial puncture must be differentiated from anastomotic aneurysms because their treatment differs substan­tially. False aneurysms following sterile arterial puncture may be treated by arterial compression under duplex imaging [11]. More recently, injection of thrombin into these false aneurysms has been shown to be safe and effective, even in anticoagu­lated patients [12]. This technique is not suitable for anastomotic aneurysms. Other radiological techniques may be used selectively for false aneurysms in inaccessible positions, such as the renal or subclavian arteries, where coil embolisation may be used to occlude the feeding vessel [13]. Again, this is rarely suitable for anastomotic aneurysms. Occasionally, it is possible to insert a covered stent across an anasto­motic aneurysm to produce local aneurysm thrombosis [14, 15] and to maintain normal distal flow. The ideal indication for this is intra-abdominal aortoiliac anas­tomotic aneurysms, where reoperation carries substantial risk. It is important that these non-operative techniques are not used in situations where there is any risk that the false aneurysm is due to infection. The most common site for anastomotic aneurysm is the groin, where non-operative techniques have not been found to be effective. The groin is also easily accessible for surgery, so direct operation is the usual intervention in this situation. [Q4: A, B, C, D] [Q3: A, B, C, D]

Some 80 per cent of anastomotic aneurysms occur in the groin, and they have the highest incidence of infection as their primary cause; approximately 30 per cent contain pathogenic bacteria. A high level of clinical suspicion of infection must be maintained, and Gram staining of all clots and removed graft should be carried out as a matter of routine. Perioperative antibiotics should be continued until results are available.

Grafts with a more indolent level of infection that becomes apparent only after microbiological investigation may be treated less radically. It is safest to assume that all femoral anastomotic aneurysms are contaminated. If prosthetic material is needed for repair, then measures used to reduce the chance of reinfection include the use of a rifampicin-soaked, gelatine-coated Dacron graft and gentamicin beads laid in close proximity. The reinfection rate after such procedures is 10 per cent [19].