Aneurysmal disease in the femoral triangle encompasses a spectrum of pathology; it includes both degenerative aneurysm in native vessels and the more commonly encountered false aneurysms. Whereas a true aneurysm is an abnormal dilatation involving all three layers of the vascular wall, a false aneurysm results from a rent in the integrity of either a native vessel or a previous vascular suture line, the ‘wall’ of the aneurysm being composed of surrounding scar and inflammatory tissue. The incidence, clinical importance, and management of these diverse lesions vary considerably.

Femoral artery aneurysms may be true aneurysms due to atherosclerotic degeneration of native vessels or false aneurysms that are either: (1) anastomotic aneurysms at the site of prior vascular reconstructions, or (2) false aneurysms, secondary to penetrating trauma or catheterization of the femoral artery (Table 1) 181. Iatrogenic false aneurysm is the most commonly encountered lesion, in accordance with the ever increasing numbers and types of transarterial femoral catheterization procedures. An important complicating factor in the management of the false aneurysm is the presence or absence of infection. Infection can be the principal cause of the false aneurysm but an established femoral aneurysm of any type can be secondarily infected by haematogenous seeding. Acute necrotizing infection may be a cause of false aneurysm, particularly in intravenous drug abusers who use the femoral vessels as sites of vascular access.

While atherosclerotic femoral aneurysm is the second most common peripheral aneurysm (after popliteal artery aneurysm), it is, in fact, an uncommon clinical problem. Furthermore, atherosclerotic femoral aneurysms are generally detected in patients undergoing evaluation for aneurysmal disease elsewhere in the vascular tree. As is the case with the more commonly encountered popliteal aneurysm, atherosclerotic femoral aneurysm has a strong predilection for the male sex, is bilateral in over 70 per cent of the cases, and is seen in association with aortoiliac aneurysmal disease in 85 per cent of the patients. In the largest clinical series reported, only 3 per cent with aortic aneurysm had simultaneous femoral aneurysm.

Diagnostic uncertainty in femoral aneurysm disease generally involves the distinction between diffuse arteriomegaly and genuine aneurysm. In this regard, criteria similar to those developed for the definition of a popliteal aneurysm are appropriate. A femoral artery can be considered aneurysmal when its maximum diameter is 1.5 times or more that of the upstream normal external iliac artery. In addition to the physical examination, ultrasound evaluation combined with colour Doppler examination provides excellent resolution and a high degree of diagnostic accuracy. The demonstration of laminated thrombus within the aneurysm cavity is important in making the distinction between an ectatic artery and a true aneurysm. Ultrasound examination also allows an accurate measurement of size which may be important in determining whether aneurysm repair is indicated. As is the case in aneurysm disease in a variety of locations, angiography is not required for diagnosis, but it is essential in planning the technical details of operative repair.

Controversy exists as to the natural history and clinical importance of untreated femoral aneurysm. Much of the earlier literature simply reviewed operated cases, and an appreciation of the natural history was not available. Clearly, symptomatic aneurysms and those larger than 3 cm should be repaired. In one large series symptoms developed in less than 3 per cent of 40 patients followed without operation. We favour operations for all lesions larger than 3 cm, particularly if ultrasound examination demonstrates mural thrombus. These criteria are also applied to the patient with simultaneous aortic and femoral aneurysm; that is, the aortic graft may need to be carried to the femoral level if independent criteria for repair of the femoral aneurysm exists.

The technical aspects of operative repair relate to the extent of the aneurysm (Fig. 1) 272. Femoral aneurysms have been classified as either Type I, terminating proximal to the common femoral artery bifurcation, or Type II, where the aneurysm involves the origin of the profunda femoris artery. Type I aneurysms are simply repaired with excision and interposition of a prosthetic conduit, as these arteries will generally be too large to repair with a vein graft. When the aneurysm extends into the femoral artery bifurcation, the details of the repair are somewhat more complex. Since these vessels tend to be large, a short segment of 12 × 6 mm Dacron bifurcation graft for separate anastomoses to the profunda and superficial femoral arteries is used. If concomitant femoral popliteal reconstruction is required to treat distal ischaemia, it will generally be necessary to carry out two separate reconstructions, with the femoral popliteal graft arising from the primary femoral artery reconstruction. The temptation simply to excise the anterior wall of the aneurysm, and close the defect with the proximal hood of a simultaneous femoropopliteal bypass graft should be avoided, as the remaining femoral artery may become aneurysmal.

False aneurysm of the native femoral artery, secondary to percutaneous arterial catheterization, is a common problem for the vascular surgeon (Fig. 2) 273. The incidence of this problem increases with the complexity and size of the catheters and sheaths introduced into the femoral artery: reported incidences for simple diagnostic cardiac catheterization are in the 0.5 per cent range, but this figure can increase to greater than 10 per cent after the percutaneous introduction of an intra-aortic counterpulsation balloon pump. Obviously, arterial complications of such procedures are not limited to false aneurysm formation and local thrombotic complications are even more common than false aneurysms. Traumatic femoral arteriovenous fistula formation can also occur, either in association with, or independent of, the false aneurysm. A characteristic systolic/diastolic murmur, audible with the stethoscope, is diagnostic of this condition.

While the diagnosis of femoral false aneurysm may be straightforward on the basis of a tender pulsatile mass, it may be difficult to distinguish a false aneurysm from an uncomplicated periarterial haematoma in the period immediately following the catheterization procedure. In such circumstances, a colour flow Doppler examination is simple, and accurate. A scan can frequently localize the origin of the false aneurysm, information that may be helpful in the planning of the operative repair. Despite the fact that indwelling sheaths may be left in the femoral artery for some period of time, infection in these lesions is distinctly uncommon.

Repair of native vessel femoral false aneurysm is generally indicated. Since the natural history of these lesions is to enlarge progressively, they can produce significant local pain and venous obstruction, and they are capable of thrombosis and distal embolization. Spontaneous thrombosis of false aneurysm occurs frequently. Patients after coronary artery balloon angioplasty were sequentially followed with colour Doppler scans and spontaneous obliteration was observed in small, otherwise undetected false aneurysms. We have observed this phenomenon in a few patients. It is also obvious that late appearance of progressively enlarging false aneurysms is seen in an active clinical practice. We routinely repair false aneurysms since such patients are generally referred with coexistent large haematomas or appreciable local pain. Affected patients are frequently undergoing investigation for acute cardiac problems, and repair under local anaesthesia is the preferred technique. Proximal control is obtained at the level of the inguinal ligament; distal control of the superficial and profunda femoris arteries is unusually not needed since control generally requires a fair amount of dissection in a patient under local anaesthesia. In addition, simply obtaining proximal control and then approaching the arterial defect directly through the aneurysm cavity simplifies the operation. Once the aneurysm cavity is entered, there is generally substantial back bleeding, even though the common femoral artery is clamped proximally. Bleeding can be controlled with a finger or cottenoid dissector, while the contents of the aneurysm cavity are evacuated and the anterior wall of the artery identified. Identification is a key technical manoeuvre, since failure to expose the arterial surface leads to placement of sutures in the extravascular tissues, and failure of the repair. Following the identification of the defect in the arterial wall, one or two monofilament sutures, placed parallel to the long axis of the artery will generally close the defect. Careful preoperative evaluation of the distal circulation is necessary to assess the possible requirement for distal catheter embolectomy, although embolectomy is rarely indicated. It is also critical to assess the adequacy of the distal circulation following repair. Repair is generally assessed by intraoperative pulse volume recordings. If these suggest a problem at the site of the repair, the surgeon must dissect the branches of the femoral artery, and reopen the femoral artery with the longitudinal arteriotomy. This usually occurs in the setting of a highly diseased femoral artery, and local repair with a vein patch angioplasty is required.

Infected femoral aneurysms present the surgeon with a difficult clinical problem, the goals of treatment being the eradication of intravascular sepsis and preservation of limb viability. Infected aneurysms in the femoral triangle occur in a variety of clinical settings, including infection of iatrogenic false aneurysm, usually secondary to bacterial contamination from indwelling catheters and sheaths, those occurring in intravenous drug abusers injecting themselves about the femoral triangle, and haematogenous inoculation of a true atherosclerotic aneurysm. Since true atherosclerotic aneurysms are uncommon, superinfection is rare. As stated above, despite the frequency of iatrogenic false aneurysm in a large hospital setting, secondary infection of these lesions is also rare.

The worst form of the disease is that found in intravenous drug abusers. Long-standing intravenous drug abuse combined with factors such as subsequent obliteration of available venous conduits, a proclivity for polymicrobial necrotizing infections, and the sociomedical stratum in which this problem is likely to be encountered, make this entity a challenging clinical problem; the dual goals of eradication of arterial sepsis and preservation of limb viability may not be feasible because of the nature of the infection. Infected femoral artery aneurysm in a drug abuser is generally associated with extensive arterial sepsis, frequently with the threat of rupture and bleeding through the overlying infected, and sometimes necrotic, skin. These patients frequently present themselves as a true vascular surgical emergency. The diagnosis may not be obvious, and appropriate blood cultures, careful physical examination for evidence of distal emboli, evaluation for concomitant infective endocarditis, and complete angiographic study to look for additional false aneurysms are indicated.

Clearly, the frequency with which the surgeon encounters this problem will be a function of the patient population he serves. Reddy and colleagues, in reporting the largest clinical series of infected femoral aneurysms in drug abusers, have outlined the principles of treatment in this particular clinical setting. These involve complete arterial excision back to healthy arterial wall, and closure of the transected artery with monofilament suture material, in addition to radical debridement of all surrounding necrotic and infected soft tissue. The obvious dilemma in this circumstance involves a decision about the need for, and technical aspects of, arterial reconstruction to maintain limb viability. Above-knee amputation is necessary in one-third of patients in whom arterial excision involves the common femoral artery bifurcation. If the sepsis is limited to the common femoral artery, such that the distal arterial closure can be completed above the femoral bifurcation, the surgeon can then anticipate continued limb viability by virtue of the circumflex femoral and profunda femoris collateral pathways. Thus, the wisdom of arterial reconstruction is tempered by the absolute need for immediate revascularization, and the nature of the patient. Reddy and colleagues advocate a selective approach to revascularization in the intravenous drug abuser and avoid insertion of prosthetic grafts because of the threat of late infection. Others have adopted a more aggressive policy towards limb preservation and performed routine reconstruction after excision of the infected false aneurysm.

The technical aspects of arterial reconstruction vary with the clinical setting. The bacteriology and extent of sepsis dictate the feasibility of either in-situ reconstruction or extra-anatomic reconstruction. One would not hesitate to place a vein patch repair or a saphenous vein interposition graft in a contaminated groin, but in the face of necrotizing arterial sepsis a vein patch would be doomed to fail, exposing the patient to the risk of early haemorrhage. The principles of treatment involve debridement of all infected arterial and soft tissues, placement of suture lines, whether arterial closures or anastomoses, in normal arterial tissue, and the interposition of healthy soft tissue coverage. Transposition of the proximal sartorius muscle over femoral arterial repairs in the groin is a simple, convenient, and effective means of providing soft tissue coverage.

Autogenous tissue should be used when placing a vascular reconstruction in a contaminated field. If necrotizing or frankly suppurative arterial sepsis is present, arterial excision and extra-anatomic reconstruction will be necessary. In this circumstance, preoperative arteriography is mandatory to plan the reconstruction. The obturator foramen bypass provides a convenient and effective means to circumvent arterial sepsis in the groin. Inflow for this bypass may be from either native iliac artery, aorta, or the ipsilateral limb of a previously placed aortofemoral bypass graft. Ideally, the extra-anatomic reconstruction is placed first, and groin exploration is accomplished following completion of the ‘clean’ procedure. A prosthetic conduit may be acceptable for an obturator foramen bypass, if the distal circulation is adequate to sustain its patency.

Anastomotic aneurysm occurs when either partial or total disruption of a suture line between a native vessel and vascular graft occurs, vascular integrity being maintained by a fibrous tissue capsule which constitutes the wall of the false aneurysm. Because of lack of tensile strength of this fibrous tissue capsule, the natural history of such an aneurysm is to continue to enlarge. In the femoral region, anastomotic aneurysm most commonly occurs at the site of the femoral anastomosis of an aortobifemoral bypass graft. Numerous clinical series have reported an incidence ranging from 2 to 8 per cent. In most reports, the femoral anastomotic aneurysm appears at a mean of 5 to 6 years after the initial operation, although this figure, as well as the overall reported incidence, varies with duration of follow-up. In the past, the aetiology of anastomotic aneurysm was attributed to the use of silk sutures, and poor quality control in the prosthesis itself. Since silk is a biological material, it is slowly absorbed with time.

Human beings never ‘heal’ a vascular prosthesis; integrity of the suture line is continuously dependent on the integrity of the sutures themselves. With the use of permanent, non-absorbable sutures, and improved prosthetic grafts, the aetiology of anastomotic aneurysm has gradually shifted to factors related to the host, rather than the implanted materials. Ongoing degeneration of a diseased arterial wall is the principal cause of development of anastomotic aneurysm in the modern era. However, a number of additional factors and early postoperative complications have been implicated as contributing to false aneurysm formation. These include graft infection, non-infectious postoperative wound complications, such as haematoma or seroma communicating with a fresh anastomosis, the need for local endarterectomy at the site of the femoral anastomosis, and inadequate suture bites on a thick, diseased femoral artery. In addition, since the femoral anastomosis is the most common site of an anastomotic aneurysm, physical factors relative to the distraction forces produced by joint motion and compliance mismatch between prosthesis and native artery contribute to false aneurysm formation.

The diagnosis of an anastomotic aneurysm is generally straightforward on the basis of physical examination and other confirmatory tests are not usually needed prior to complete angiography, which is necessary to plan the appropriate surgical therapy. A complete arteriographic study should be performed to search for additional false aneurysms at other suture lines, particularly at the proximal aortic suture line, since a subpopulation of patients afflicted with anastomotic aneurysm are subject to multiple aneurysms and multiple recurrences. As is the case with other false aneurysms, anastomotic aneurysms are likely to enlarge. They can cause symptoms of local compression and arterial ischaemia from embolism and in-situ thrombosis. In addition those located at aortic or iliac suture lines are capable of rupture. Thus, repair of all but the smallest false aneurysms is recommended.

The surgical management of anastomotic aneurysm initially relates to technical steps which are important in prevention of the problem. These have been alluded to above, and involve the use of permanent non-absorbable sutures, large suture bites on diseased femoral arteries, avoidance of excess tension, and careful attention to wound haemostasis and closure at the initial operation. Prophylactic antibiotics are used routinely.

Repair of femoral anastomotic aneurysm may be carried out under either general or regional anaesthesia. The old incision is reopened and proximal control of the graft is obtained above the aneurysm. Although dissection in a reoperated groin can be difficult, exploitation of the principles of traction and countertraction, and sharp dissection with a small scalpel blade, are very effective. There is no role for bypassing or avoiding the multiply operated groin simply because it may be difficult: bypassing does not prevent progressive enlargement of false aneurysms, and is likely to result in the sacrifice of the vital profunda femoris artery. Following control of the limb of the old graft and the native common femoral artery, the surgeon decides whether complete dissection of the distal vessels, for distal control, is appropriate. Since distal control may involve extended dissection with the possibility of injury to the profunda femoris artery, we prefer to open the aneurysm after proximal control is obtained and use intraluminal indwelling balloon catheters for distal control. Furthermore, if it subsequently becomes necessary to dissect out additional length of the profunda femoris artery, the balloon catheter serves as a stent of sorts. Initial distal control of the uninvolved profunda femoris artery, and then retrograde dissection to the area of the aneurysm, is neither necessary nor desirable. Following exposure and opening of the false aneurysm, it is important to instil heparinized saline solution into the now clamped limb of the aortofemoral graft, to prevent in-situ clot development during the period of clamping. At this point, a careful search for contributing factors to false aneurysm formation should be made. If any evidence of infection is present intraoperative Gram stains should be used to assess the necessity for extra-anatomic reconstruction. If only a portion of the old suture line is disrupted, the surgeon may be tempted to reclose this with additional interrupted sutures. This proclivity is to be avoided, as it increases the chance of a recurrence. Instead, the entire suture line should be taken down, and the native femoral artery trimmed back to healthy artery.

At this point, the surgeon must decide whether a new end-to-side type of reconstruction is feasible, or whether the new reconstruction should be in end-to-end fashion, thereby sacrificing retrograde flow in the native common femoral artery. The guiding principle should be a technically perfect reconstruction to undiseased distal artery, frequently carried out onto the profunda femoris artery in the manner of a profundaplasty. In such situations, the use of multiple interrupted sutures, at least at the toe and the heel of the reconstruction, is preferred. Reconstruction is generally accomplished with a new short segment of prosthetic graft, which is then simply sutured proximally to the amputated old prosthesis, in end-to-end fashion. Following completion of the reconstruction, adequacy of the distal circulation is ensured before leaving the operating room. Absolute haemostasis is obtained prior to wound closure.

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