Vein aneurysms are a rare vascular pathology and the popliteal vein aneurysm (PVA) represents the most common type of peripheral venous aneurysm. The first PVA was described in 1968 by May and Nissel, in a patient who presented with foot and ankle swelling (1). Since then, this pathology has been mainly described in case reports or short series. An attempt to give a definition was done by Maleti et al. (2) and MsDevitt et al. (3) who considered aneurysm any isolated venous dilation of two times or at least three times the normal diameter of the vein, respectively.

Although there are still no clear guidelines in this regard, the main risk of this condition is pulmonary embolism and a prompt medical or surgical treatment should be evaluated. The patients can be initially asymptomatic or can present lower limb swelling or pain due to a venous stasis; whereas in more advanced cases of the pathology, deep vein thrombosis or a pulmonary embolism may occur. No clear etiologic factors have been found but, interestingly enough, an association of PVA has been noticed in patients with deep or superficial vein thrombosis (4) and in muscular compression from anomalous slip of adductor muscles (5).

The aim of this report was to describe the diagnostic and therapeutic management of two patients with a saccular popliteal vein aneurysm, analyzing the literature evidence.

The authors obtained the consent to publish these two cases.

We report two cases of popliteal venous aneurysms:

A 56-year old woman came to our institution with pain in popliteal fossa associated to leg and foot swelling since months. Firstly a DUS was performed that documented the presence of a saccular aneurysm of about 24 mm of the left popliteal vein.

A 33-year old woman came for a visible mass in the popliteal fossa and upon a DUS (Fig. 1), a saccular aneurysm of about 33 mm of right popliteal vein was diagnosed. The patient was a professional football player exposed to traumatic events in the popliteal area that may be the cause of this condition.

Fig. 1. Doppler ultra-sound of popliteal fossa showing a vascularized aneurysm without thrombus.

In both cases, it was neither deep or superficial vein thrombosis nor superficial venous system insufficiency. Both patients had a normal coagulation pattern (Table 1). Anticoagulant therapy was immediately started with low-　molecular-weight heparin (LMWH) to avoid thrombosis into the aneurysm. Computed tomography angiography (Fig. 2) confirmed the presence of the aneurysm in popliteal fossa.

Table 1

Pre-operative blood tests

	Patient 1: 56 yrs	Patient 2: 33 yrs
Red blood cells	4.1×10^12/L	4.4×10^12/L
Platelets	226×10^9/L	270×10^9/L
Prothrombin time (PT)	11.3 sec	11.1 sec
Partial thromboplastin time (PTT)	28 sec	26 sec
Fibrinogen	3.1 g/L	1.4 g/L
D-dimer	<250 ng/ml	<250 ng/ml

Fig. 2. Computed Tomography Angiography (CTA): frontal (A) and transversal (B) projections.

Both patients underwent surgical treatment through tangential aneurysmectomy with lateral venorrhaphy under spinal anesthesia. A posterior approach was chosen according to the anatomical position and extension of the aneurysms that were severely adherent to the surrounding structures. Lazy S- incision was made in popliteal fossa, followed by incision of muscular fascia, isolation of popliteal vein sparing the sciatic nerve and aneurysm exposure. After systemic heparinization, tangential clamping was made (using a Satinsky clamp) at the base of the aneurysm followed by opening of the aneurysmatic sac, section of the excess aneurysmatic wall and its exclusion by longitudinal lateral venorrhaphy with monofilament 6/0 (Fig. 3 and 4). This approach (tangential clamping and venorraphy) was allowed by ultrasound certainty that there wasn’t thrombosis inside the vein. Otherwise, in case of aneurysm associated to the presence of thrombus inside the sac, a prompt proximal clamping should be needed to reduce the risk of embolization.

Fig. 3. Intra-operative images: aneurysm isolation (A), aneury-smectomy (B), venorrhaphy (C).

Fig. 4. Tangential vein clamping and lateral venorraphy.

The post-operative course was uneventful and both patients were discharged in third postoperative day. Anticoagulant therapy has been continued for one month after surgery. DUS follow-up at 3 months revealed normal patency of the femoro-popliteal vein axis.

Venous aneurysms are extremely rare, often asympto-matic and can affect different parts of the body: head and neck, thoracic or abdominal district and the extremities. A recent paper reviewed the presentation of venous aneurysms (6): venous aneurysms of the extremity have the most reported cases with numerous reviews of the literature. Popliteal venous aneurysms are the most common venous aneurysms of the lower extremity with more than 200 cases described in literature. They are also associated with a higher risk of thromboembolic events with approximately 25% to 50% of popliteal vein aneurysms presenting with pulmonary embolism (7).

In contrast to arterial aneurysms, clear recommendations for management venous aneurysms are not well defined. The decision to intervene depends largely on their location and the weight of potential consequences of the aneurysm as pulmonary thrombo-embolism vs complications of surgical intervention. Bergqvist et al. noticed a slight female and left-sided preponderance (8). Histologically, internal elastic lamina deterioration, internal sclerosis and elastin insuffi-ciency have been described as main features (9).

Upper extremity venous aneurysms are typically asymp-tomatic and is not described a high risk of VTE (6). On the other hand, the risk of VTE in case of lower extremity venous aneurysms seems higher: Maldonado et al. (10) reported five cases of mortality related to pulmonary embolism in patients undergoing medical management for popliteal venous aneurysms. This data reinforces the indication for surgical treatment always in case of popliteal aneurysm.

In literature the role for endovascular therapy for popliteal venous aneurysm is not described. The open surgical techniques described are different: the most common technique is tangential repair and lateral venorrhaphy. This technique requires clamping, sometimes tangential, of the vessel, ensuring complete removal of the aneurysm and precise reconstruction of the vessel. Beaulieu et al. (11) in a recent paper described nine cases of closed plication of the popliteal vein in which pledgeted horizontal mattress sutures are placed to plicate the aneurysmal portion of vein. This technique is sure quicker and does not require clamping, although it does not allow to have control of the vessel lumen, in case of presence of thrombi and avoiding restenosis during suturing. More procedures include aneurysm resection, end- to-end anastomosis (especially for saccular PVAs), aneurysm resection and interposition grafting with either great saphenous vein or a spiral vein graft. Civilini et al. (12) described an alternative solution to restore physiological vein calibre by staple aneurysmorrhaphy.

Popliteal vein aneurysms are uncommon but have been investigated, especially in case of recurrent thrombo-　embolism events. The treatment is only surgical and the tangential repair and lateral venorrhaphy is the most common technique. Anticoagulant therapy should be set in the pre-operative period until at least the repair of the aneurysm. This aneurysm can be easily approached by prone positions according to the surgeon experience and the extension of the aneurysm.