External carotid artery pseudoaneurysm following microvascular free flap reconstruction. The role of endovascular thrombin injection in embolization: a case report and review

Abstract

Pseudoaneurysm at the anastomosis of the free flap following ablative head and neck surgery is uncommon. We present a case of external carotid artery pseudoaneurysm in a patient who had previously undergone a subtotal glossectomy, neck dissection, and radial forearm free flap reconstruction. The traditional treatment for pseudoaneurysm has been open surgical repair. Our patient underwent successful treatment with an endovascular embolization utilizing thrombin injection of the aneurysmal sac. This case highlights the role of interventional radiology in the management of this rare but important complication of microvascular reconstructive surgery.

Introduction

Carotid pseudoaneurysms are rarely encountered in clinical practice. They are most commonly a sequela of neck trauma, and most often involve the internal or common carotid vessels. They are associated with systemic hypertension and radiotherapy. Reported cases of external carotid pseudoaneurysm are rare, with an incidence of 0.07% and associated mortality of up to 30%.

Conventional management has entailed open surgical repair and ligation with or without bypass and arterial reconstruction. Minimally invasive endovascular techniques, such as stenting or coiling, have become increasingly established. We present a case of external carotid artery pseudoaneurysm following microvascular reconstruction, managed with endovascular therapy.

Case report

A 56-year-old male with a T3N0M0 squamous cell carcinoma of the tongue, underwent a right subtotal glossectomy, right selective neck dissection, and radial forearm flap reconstruction. The condition of the vessels was poor and the radial artery was anastomosed to the external carotid artery (end-to-end), two centimetres distal to the carotid bifurcation. Initial postoperative recovery was uneventful and he was discharged home 10 days post-surgery.

At 4 weeks following surgery, a rapidly increasing swelling developed in the right upper neck, with no other associated symptoms. Examination revealed a tender, expansile swelling in the right upper neck. His intraoral flap was well perfused and he was systemically well.

An ultrasound scan and computed tomography (CT) angiography, revealed a 5-cm pseudoaneurysm at the site of the microvascular anastomosis. The neck of the pseudoaneurysm measured approximately 4 mm ( Figs. 1–3 ).

Fig. 1
Axial CT showing a large (5 cm) pseudoaneurysm arising from the right external carotid artery, with the feeding vessel arising from the site of free flap anastomosis.

Fig. 2
Digital subtraction angiogram showing a pseudoaneurysm of the external carotid artery at the site of the anastomosis.

Fig. 3
(a) Pre-procedural Doppler ultrasound demonstrating active blood flow within the right external carotid aneurysmal sac. (b) Post-procedural Doppler ultrasound demonstrating completely thrombosed aneurysmal sac.

Endovascular embolization with thrombin injection directly into the aneurysmal sac was performed under local anaesthesia, with the effect of coagulating the false lumen. Selective angiography with balloon blocking of the neck was used to assist with the procedure and prevent thrombin from migrating into the flap-feeding vessel. Access was obtained via the right femoral artery and the guide wire was advanced across the pseudoaneurysm into the distal right external carotid artery (ECA). A destination sheath was then placed. An over-the-wire balloon was used to block the neck of the pseudoaneurysm, and thereby occlude flow into and out of the aneurysmal sac. Ultrasound-guided percutaneous injection of thrombin was carried out with successful occlusion of the aneurysmal sac. Patency of the flap pedicle was confirmed by superselective angiography as well as the easy passage of the catheter through the feeding vessel. There were no complications; the flap was assessed clinically immediately following injection and free flap perfusion was preserved.

A repeat neck ultrasound scan at 48 h confirmed the pseudoaneurysm had been successfully embolized and had not recurred ( Fig. 3 a and b). Six months after the procedure, the flap is doing well and there is no evidence of local or regional recurrence.

Case report

A 56-year-old male with a T3N0M0 squamous cell carcinoma of the tongue, underwent a right subtotal glossectomy, right selective neck dissection, and radial forearm flap reconstruction. The condition of the vessels was poor and the radial artery was anastomosed to the external carotid artery (end-to-end), two centimetres distal to the carotid bifurcation. Initial postoperative recovery was uneventful and he was discharged home 10 days post-surgery.

At 4 weeks following surgery, a rapidly increasing swelling developed in the right upper neck, with no other associated symptoms. Examination revealed a tender, expansile swelling in the right upper neck. His intraoral flap was well perfused and he was systemically well.

An ultrasound scan and computed tomography (CT) angiography, revealed a 5-cm pseudoaneurysm at the site of the microvascular anastomosis. The neck of the pseudoaneurysm measured approximately 4 mm ( Figs. 1–3 ).

Fig. 1
Axial CT showing a large (5 cm) pseudoaneurysm arising from the right external carotid artery, with the feeding vessel arising from the site of free flap anastomosis.

Jan 19, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on External carotid artery pseudoaneurysm following microvascular free flap reconstruction. The role of endovascular thrombin injection in embolization: a case report and review
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