Tangential Resection of a Popliteal Vein Aneurysm in a Patient Complaining of Localized Popliteal Pain.

A 48-year old man presented with left popliteal pain. A 2.2×1.6 cm sized saccular aneurysm at the level of the left popliteal fossa was diagnosed by ultrasonography. Tangential aneurysmectomy and popliteal vein repair was performed uneventfully. The patient fared well for a year without symptoms. Popliteal vein aneurysms are rare and typically found in patients with fatal thromboembolic features without warning symptoms. Fortunately, our patient had localized pain which was helpful in its early diagnosis and treatment.

INTRODUCTION

Popliteal vein aneurysms (PVAs) are rare diseases [1], and may bring about serious complications such as pulmonary embolism [2]. Once a serious complication occurs, patients with PVAs can reach fatal conditions. Early suspicion and recognition of these diseases are very important to prevent catastrophic complications. PVAs tend to be found in patients with severe thromboembolic features without warning symptoms, such as leg pain and swelling [2]. Unusually, but fortunately in our case, the patient had local pain without thromboembolic features. This was helpful in its early diagnosis and treatment.

CASE

A 48-year old man presented with left popliteal pain that had developed 3 months previously. The pain was aggravated when the knee joint was extended in the standing position. He had first visited an orthopedic clinic where a magnetic resonance imaging (MRI) scan showed a cystic lesion around the left popliteal vein with no abnormal findings explaining the pain (Fig. 1A).

Fig. 1.

(A) Magnetic resonance imaging scan showed a saccular type aneurysm at the popliteal area. (B) A 2.2×1.6 cm sized saccular type aneurysm was confirmed by ultrasonography at the posteromedial aspect of the left popliteal vein in standing position.

His previous medical history was unremarkable. There were no deep vein thrombosis-related symptoms like calf swelling or tenderness, and no pulmonary thromboembolic events. Ultrasound (US) Doppler examination done immediately at the time of his visit to our clinic with the patient in a standing position revealed a 2.2×1.6 cm sized saccular aneurysm at the posteromedial aspect of the left popliteal vein at the level of the popliteal crease (Fig. 1B).

Preoperative computed tomography (CT) venography was done to evaluate the lesion and adjacent structures. The PVA was confirmed at the same location as seen in the US Doppler. The aneurysm measured 2.0×1.5 cm in the supine position (Fig. 2A). A lung perfusion scan was done to rule out pulmonary thromboembolism; no perfusion defect was found.

Fig. 2.

(A) Preoperative computed tomography (CT) scan shows a left popliteal vein aneurysm (arrow). (B) Postoperative CT scan, checked one year after the surgery, shows nearly normal diameter of the left popliteal vein (arrow).

PVA resection and popliteal vein repair were planned. US mapping was done for accurate surgical incision in the operation room. The patient was placed in the prone position after spinal anesthesia. An S-shaped skin incision was made above the popliteal fossa. Meticulous dissection was performed to isolate the popliteal vein including the aneurysm without the use of electro-cautery, to avoid tibial nerve injury (Fig. 3A). The entire aneurysmal sac was isolated and clamped with a side-biting clamp. The aneurysm was resected tangentially while maintaining the venous flow and the remaining vein was repaired with 7-0 polypropylene suture (Fig. 3B). After the removal of the clamp, a partial aneurysmal dilatation was remaining. The lesion was repaired using a horizontal mattress suture with 7-0 polypropylene. Grossly, no other dilatation of the popliteal vein was seen in the operative field.

Fig. 3.

The surgical findings. (A) Popliteal vein was entirely exposed and the tibial nerve was safely looped beside. (B) Aneurysmal resection was done and the remaining popliteal vein was repaired with a 7-0 polypropylene suture.

Postoperative anticoagulation was done to prevent venous thrombosis. Heparin was injected for 3 days after the operation. Medication was then switched to warfarin and maintained for three months. The patient was discharged at the sixth postoperative day without symptoms or complications. CT venography and US Doppler at 1 month and 1 year after the operation confirmed that the popliteal vein was intact without aneurysmal change (Fig. 2B). The patient fared well after discharge.

DISCUSSION

PVAs are very rare. Recognition of this aneurysm is important because it can lead to catastrophic results such as pulmonary embolism. The aneurysmal change results from increased hemodynamic pressure at the site of venous mural weakness. Trauma, inflammation, congenital weakness and degenerative changes are possible causes [1]. Aneurysmal dilatation may prelude to formation of focal thrombi as a result of the venous turbulent flow. The presence of thrombi in a patent venous system differs from the pathophysiology of deep vein thrombosis. PVAs tend to be found in patients with severe thromboembolic features without warning symptoms, such as leg pain and swelling [2]. Unusually, but fortunately in our case, the patient had local pain, which was helpful for early diagnosis and treatment. The local pain may have originated from the PVA itself or from direct compression of neural structures by the aneurysmal dilatation.

The characteristic microscopic features of PVA are known as the fragmentation of elastic lamellae and fibrosis replacing the medial smooth muscle [3]. In our case, histologic stains showed destruction of the local architecture in the intima and media with invasion of fibrous tissues and fragmentation of the elastic lamellae (Fig. 4).

Fig. 4.

Histologic staining of the specimen reveals destruction of the local architecture in the intima and media with invasion of fibrous tissues and fragmentation of the elastic lamellae (Elastin staining, ×100).

The size criterion for treatment of PVAs has varied in different publications, with twice and three times the normal vein size (5–7 mm) being advocated [4,5]. However, which modality is best to use and the influence of body position on size are unknowns.

Diagnostic modalities that can be used include ascending venography, CT, MRI and duplex US. Of these, US is considered the best method. US is noninvasive and portable; the physician can evaluate aneurysm size, thrombus extent and venous patency immediately and safely in different locations including the operation theater and outpatient office. CT or other modalities provide more accurate anatomic information, but they tend to underestimate aneurysm size because they are performed with the patient in the supine position. US can measure the true aneurysm size with the patient in the upright position because it is free from positional restrictions. Even a nonspecialist surgeon can perform US.

PVA treatment options are considered on a case-by-case basis. In patients with pulmonary embolism, surgery is the treatment of choice. Surgery is also recommended in cases of aneurysms with thrombus in the sac, as well as for saccular type or large fusiform aneurysms because of the potential risk of thromboembolism. Tangential aneurysmectomy with lateral venorrhaphy is recommended for saccular type aneurysms. Aneurysm resection with graft interposition is needed for fusiform or saccular type aneurysms where simple resection is unsatisfactory. However, if the aneurysm is of saccular type without thrombus in the lumen and is smaller than 2 cm, close observation can be safe without complications [6]. Postoperative anticoagulation typically involves 3 months of oral anticoagulation with international normalized ratio follow-up [1].

In conclusion, we report a rare case of PVA with focal leg pain that is thought to be the result of a mass effect. Because of the potentially catastrophic course of PVA, accurate diagnosis and alert treatment are needed, even if the patient is asymptomatic. Tangential aneurysmectomy and venorrhaphy can be performed safely without complications. The patient should have a long-term followup and serial ultrasonography examinations, particularly in the presence of relevant signs and symptoms.