Introduction

Vascular injuries comprise 3% of the traumas in civil societies and even in 21st century, morbidity and mortality rates are significant (₁).Lower extremity pseudoaneurysms develop after penetrating traumas leading direct vessel injury(₂). Extremity vessels are affected in 75% of the penetrating injuries. A penetrating trauma directed to vessel wall can cause an acute traumatic pulsatile hematoma by rupturing all the layers of arterial wall(₃). Hematoma is limited with adjacent tissues or organs and enlarges until it is surrounded by a chronic fibrous wall or rupture. Chronic traumatic aneurysm develops by the partial or complete absorption of periarterial hematoma in the fibrous sac, which is surrounded with adjacent tissues. Generally the term “traumatic aneurysm” is used to refer to pseudoaneurysm (₃). Pseudoaneurysm of the popliteal artery typically results from penetrating trauma rather than blunt trauma. The civilian incidence of such pseudoaneurysms constitutes 0 to 3.5% of all popliteal aneurysms (₄).Pseudoaneurysms(PSAs) must be treated as soon as possible whether acute or chronic after diagnosis with direct surgical procedure . Rupture risk, thrombosis and compression to adjacent structures can be avoided by early operation (₃).I n this study we present 11 pseudoaneurysm cases, localized at popliteal arteries' localizations developeds after penetrating injuries and our surgical repair approachs with literature knowledge.

Material And Methods

From January 2000 through December 2006, we performed revascularization eleven patients' PSAs at the popliteal arterial after gunshot (5 cases) and stab (6 cases) injuries in our Cardiovascular Surgery Department. There were 11 male patients with mean age of 36.8 years.These patients had been rendered first aid at other medical institutions. There wasn't any pulse deficit or ischemia sign and their clinical pictures and hemodynamics were stabile at first admission (Table 1).

Figure 1

We evaluated the lower extremities for ischemia, asked the patient for a medical history and performed a physical examination, all of which contributed to the diagnosis. All patients presented with a pulsating mass at the popliteal arterial level, which had developed in the late post-traumatic period (Figure 1).

Figure 2

Figure 1: Image of popliteal artery pseudoaneurysm developed at left cruris region,6 months after stab wound.

On physical examination, the patients were afebrile and hemodynamically stable.All patients had large PSAs of more than 7cm filling the popliteal fossa with variable degrees of fixed flexion deformity of the knee. They admitted to our clinic for progressive tumor, function loss and pain in the last weeks. Their effected leg was slightly cold and peripheral pulses were hardly determined when compared with the other leg.There was pulsation on the mass and a murmur was heard correlated with systolic thrill in all cases.Ankle/arm index was 0.65-0.8 at effected leg and ≥1 at uneffected leg. Routine biochemical tests,bleeding and coagulation timing tests were resulted normal in all patients. Lower extremity arterial and venous colored Doppler ultrasonographic (CDUSG) tests showed a giant hematoma with 7-13 cm diameter and hemorrhagic liquid areas with various concentrations at their PSAs' localizations. There was a saccular image with 7-13 cm diameter at all cases and the “to and fro” flow pattern was thought to indicate pseudoaneurysm (Figure 2).

Figure 3

Figure 2: To and fro” flow pattern in sacculus, evaluated as pseudoaneurysm indicator.

No patient had an arteriovenous fistula. Venous structures were normal in all patients. Because of inadequate information about the distal runoff vessels, we performed conventional arteriography and found the localized PSAs, and adequate distal runoff (Figure 3). Each patient underwent surgery after the diagnosis of late post – traumatic popliteal arterial pseudoaneurysm was made.

Figure 4

Figure 3: Angiographic image of pseudoaneurysm sac.

Results

The median interval between injury and presentation was 4 months (range 6 weeks to 1 year). Bupivacaine was used for spinal anesthesia in all patients. Our surgical applications for 11 patients are in Table 2.

Figure 5

We performed elective surgery, using generally the follow principles in all cases with a medial approach to the popliteal artery aneurysm. It was determined with skin incision paralel to the popliteal artery course. Exploration showed that adjacent vein and nerve structures weren't damaged and only artery was injured.Saphenous vein graft, that used for five cases was taken from contrlateral healthy extremity. The common femoral artery over the groin and the distal popliteal artery below the knee were exposed.After systemic heparin was administered,control of the proximal femoral and distal popliteal arteries was accomplished. The aneurysm was opened longitudinally, a large volume of clot was removed, and the aneurysm was confirmed to be a false aneurysm (Figure 4).

Figure 6

Figure 4: Abandoned organized thrombus in pseudoaneurysm sac after opening the capsule.

In order to avoid increasing the risk of major hemorrhage or nerve injury, we did not resect the aneurysmal pouch completely. We limited the resection by preserving the adjacent tissues. Saphenous vein graft's diameter was not enough for interposition for cases no:9 and 10,so patency was constructed with 6mm ringed expanded polytetrafluoroethylene(e-PTFE:Gore-tex) tube graft interposition. The capsule was dissected and evaluated histopathologically and microbiologically. The wound was closed in layers with a closed drain in place. All distal pulses were similar to opposite ones during postoperative period. Postoperatively low molecular weight dextran (500 ml / day), pentoxyphylline (300 mg/day) and anticoagulant (25.000 U/day unfraxioned heparin with ACT/12h control) were given for 3 days. Microbiologic examination results of the aneurysmal capsule were negative for microorganisms. Histopathologic evaluation of the pseudoaneurysmal capsules showed that they were all hematomas, with extravasation in the vessel wall lumen, with inflammatory infiltration and hyalinization. Histologically, the well encapsulated aneurysmal sac lined organized hematoma and fibrous tissue replaces the arterial wall (Figure 5).

Figure 7

Figure 5: ıllustrate shows the well encapsulated aneurysmal sac consisting of connective tissue replaces arterial wall (Hematoxylin and eosin, orginal magnificationx)

Hematoma is invested by fibrous tissue with the deposition hemosiderin pigment, typical of walled off hematomas elsewhere in the body. Pseudofibrous capsul did not have any layer of the arterial wall (Figure 6).

Figure 8

Figure 6: Low magnification demonstrates a large chanel lined fibrous tissue with a sharp demarcation between normal media and fibrous lining of the pseudoaneurysm (Hematoxylin and eosin, orginal magnificationx).

There were no deaths or graft related complications.In all cases, pulsation was positive upon digital examination at the distal pulses during the early postoperative period and they had equal ankle-brachial indices in the lower extremities. All patients were able to completely straighten the leg at the time of discharge. The late postoperative follow-up examinations were performed at our clinic and Doppler ultrasonography was performed after 2 months. The early (in first month) and late graft patency rate was 100% and we found no other sequelae during the late period. The mean follow-up was 2.2 years (range 4 months to 6 years), and the mean time to discharge was 5.5 days (range 5 to 8 days).

Discussion

Most pseudoaneurysms (PSAs) are the result of penetrating injuries (₅). PSAs of the lower extremities' arteries are very rare and ocur as a late complication after arterial injury(₆).Especially,traumatic pseudoaneurysms of the popliteal artery are rare in civilian vascular surgery practices (₄). It must be thought that patient with trauma history and pulsatile mass can have pseudoaneurysm (₃). Even with severe arterial injury,ischemia signs can not be seen distal to injury(₇). Especially cases without hypotension and with developed collateral vessel system,distal pulses can be palpated with arterial tears (₇). In a study of Peck, distal pulses could be palpated in 10% of the patients with severe popliteal arterial injury(₈). Palpated pulse can be felt with intimal flap, smooth fresh thrombus or collaterals (₁). In some of the vessel injuries,there isn't significant injury findings and necessary prevention measures are not taken so,serious complications and even death can be seen. Therefore if injury is proximal to large vessels,these patients must be closely controlled and if suspicion aroused arteriography must be performed (₁). Angiographic intervention is recommended for gunshot and especially for buckshot injuries because more than one vessel may be involved (₉). Arteriography supplements the diagnosis and allows better preoperative planning. The status of the runoff vessels, which can be seen on the arteriogram, is particularly useful for the examination of patients who have popliteal aneurysms. Early diagnosis of a traumatic popliteal artery pseudoaneurysm is important in order to avoid dangerous sequelae (₄). We performed angiography in all patients.

Clinical signs of pseudoaneurysms include pulsatile mass, murmur over its localized region, palpable thrill, pain and extremity edema (₁₀). Our patients had all these symptoms. Pseudoaneurysms following trauma cause pain by compressing the adjacent structures can contain thrombus and can cause regional ischemia due to distal embolus (₁).

The popliteal artery pseudoaneurysm, when large enough or superficially located, is generally palpable. Duplex ultrasound should be considered as the 1st method of investigation. This technique has been used successfully for the detection and follow-up of pseudoaneurysms (₄). Duplex ultrasound has an excellent sensitivity and specifity spectrum and it shows the blood filling the cavity as well as jet – flow passing from arterial defect (₁₁). It's advantages are low cost, utility in various treatment choices and low time consumption. In addition to its use in making the diagnosis, it provides detailed information about the dimensions, morphology and neck anatomy of the pseudoanurysms, the blood flow through the pseudoaneurysms and the relation of pseudoaneurysms with the adjacent vessels (₁₀).

Treatment options for pseudo-aneurysm of the popliteal artery include coil embolisation, ultrasound guided compression, percutaneous injection of thrombin, and open surgery (₁₂). The accepted methods of managing aneurysms of the popliteal artery are resection with interposition grafting or ligation accompanied by arterial bypass (₄,₅).

Endovascular repair methods are not used routinely for popliteal pseudoaneurysm treatment. Generally it is preferred for the conditions followed; complex arterial aneurysmal lesions may be difficult or impossible to treat successfully by standard surgical techniques when severe medical or surgical comorbidities exist or technically impossible cases (₆). Although it is technically possible to place stent for femoral or popliteal pseudoaneurysms, the patency rate is between 43% and 87% and not satisfactory(₁₀,₁₃).Tool migration or fracture and endoleak are complications specific to stent-graft repaire and can be improved by stent excision with open repair (₁₃).

Open surgical repair should always be the first choice of treatment (₁₀). Traditional surgery is still considered to yield the best results. For surgical reconstruction of late complications of arterial injuries such as fistula and pseudoaneurysm, end to end anastomosis is the first choice of treatment and when it is not possible to perform end to end anastomosis, saphenous vein graft interpositioning in recommended (₂). Today, many clinics prefer autogenous grafts which are more resistant to infection and have an elongated patency for extremity vessel injuries (₁₄). Especially for popliteal and infrapopliteal injuries autogenous grafts must be used, because thrombosing risk is high in synthetic grafts with a diameter less than 6 mm(₁₄). We must preferred the conduit e-PTFE for two cases because saphenous vein graft's diameter was not enough for interposition.

We also preferred a medial surgical approach to the leg, because it is easy to perform and when the patient is supine position it offers many choices. Besides tibial vessels, vena saphena manga can also be exposed easily with this method. It is very important to reach posterior and peroneal vessels for distal artery by pass (₁₃). Additionally, if the situation of the popliteal artery located at the upper patella level is worse than expected, this approach provides enough inflow from superficial or common femoral artery.

As a conclusion; today, vessel injuries and late-period complications keep increasing in parallel with the increase in violence and crime in the social life. Physical examination is not enough for perforating injuries directed to extremity arteries and noninvasive and if necessary invasive investigations must be used to determine the complications. As a late-complication, the pseudoaneurysm must be repaired with traditional open surgery to prevent the extremity function and vitality. In addition to the surgical procedure, interventional radiological techniques such as endovascular intervention and embolization can be used for the treatment of pseudoaneurysms They have advantages such as of low blood loss, reduced anesthesia requirement in patients with poor general health and centrally located pseudoaneurysms. We recommend that open surgical repair should be performed as the standard approach and if necessary selective revascularization should be used together with the routine surgical repair of aneurysms.

Correspondence to

Doç. Dr. Ufuk YETKıN 1379 Sok. No: 9,Burç Apt. D: 13 35220, Alsancak – ıZMıR / TURKEY Tel: +90 505 3124906 Fax: +90 232 2434848 e-mail: ufuk_yetkin@yahoo.fr