King Edward Memorial Hospital - Departments: Radiology

A 15 year old boy had injury to the left side of the neck. At the time of injury, he underwent suturing of the contused lacerated wound. Three years later, he noticed a swelling in the lateral aspect of his neck - at the site of previous injury. The swelling increased progressively in size over 3-4 months. There was no history of bleeding from the swelling.

Examination revealed a swelling just below the left angle of the mandible in line with the carotid artery. The swelling was expansile with pulsations and had a palpable thrill. Diagnostic angiograms were performed. The left carotid angiogram revealed a left sided carotico- jugular fistula between a branch of the left external carotid artery and the left internal jugular vein (Fig 1).

Fig 1

There was an aneurysmal swelling at the site of the fistula. There was however good antegrade flow in the distal carotid vessel. The fistula site was not easily demonstrable on the diagnostic angiogram due to the high flow. Embolisation of this carotico-jugular fistula was carried out via right transfemoral route. A detachable balloon was navigated into the site of the fistula. The fistula was sealed and the balloon detached with patent carotid and jugular systems.

Post embolisation angiogram showed complete occlusion of fistula (Fig 2 , Fig 3).

Fig 2

Fig 3

Two days later, the swelling had become hard. On follow up after 6 months, the patient was completely asymptomatic. A colour doppler examination smooth and symmetric flow in both carotid and the jugular systems.

Discussion:

Traumatic fistula between the carotid and jugular system is scarcely reported. Iatrogenic cases have been reported secondary to the dialysis catheter placement in the carotid and jugular system . Conventionally they have been treated by means of surgery. The surgical treatment for the same is ligation of this fistulous communication. But, surgery is difficult as the approach for reconstruction is tedious and it carries a high risk of morbidity. Endovascular treatment is a safe and effective means of treating them . Balloons have been the cheapest and the easiest way for the treatment of arteriovenous fistulas, commonly the carotico-cavernous segment. Newer materials like covered stents are still being tried out in animal models, but have yet to be considered as treatment of choice.

Carotico-jugular fistula is a rare occurrence. It usually involves the external carotid artery and the internal jugular vein, but rarely the common or the internal carotid artery can also be involved. The common etiologies include accidental or iatrogenic trauma. Congenital and spontaneous are the other less common causes. Iatrogenic fistulas have been reported following placement of hemodialysis catheters into the internal jugular vein . Spontaneous carotico-jugular fistulas are usually seen in elderly people and can be caused by transmural dissection or rupture of pre-existing aneurysm; they have also been reported to be associated with neurofibromatosis type I . Carotico-jugular fistulas are made up of single or multiple fistulous channels. However,in most of the cases only one fistulous site is noted, as was seen in our patient.

Clinically, the patients present with swelling on the lateral aspect of the neck. Sometimes they complain of pulsatile tinnitus. On examination the swelling is pulsatile and has palpable bruit. The overlying skin is however normal. Imaging of the carotico-jugular fistulas includes colour doppler study which will show the fistulous opening between the carotid artery and the internal jugular vein with a slow flow rate across the fistula. CT/MR angiography helps to delineate the site and level of the fistula. It also helps to differentiate the fistula from the vascular tumours situated in the neck. Angiography is considered the best imaging modality. It delineates the size, flow, and the precise location of the fistulous tract. It also helps in assessing whether the endovascular treatment can be done for the particular fistula or not. Surgical treatment for this carotico-jugular fistula is usually by directly approaching and ligating the fistulous communication. During the procedure, embolisation is usually done by the means of the detachable balloon filled with contrast medium. Additional technique like using tissue glue (N-acettyl cyano acrylate) placement in the ECA is also mentioned . In cases of very small fistulous openings other embolic materials like polyvinyl alcohol particles (PVA), coils etc. can be used, but there is always a risk of pulmonary embolism if used for larger fistulas.