IMAGES FOR SURGEONS

A 68-year-old female presented with transient headache, ataxia, vomiting and diaphoresis. Her medical history was significant for smoking and hyperlipidaemia. There was no history of hypertension, diabetes mellitus, previous stroke, ischaemic heart disease or vasculitis. Notably, there was no previous trauma, infection, radiation or intervention to the neck. On examination, she was noted to be hypertensive but was otherwise well and her initial symptoms had spontaneously resolved. The patient was admitted for further investigation of a possible transient ischaemia attack. A computed tomography angiogram was unremarkable for intracranial pathology, however, demonstrated a highly tortuous right internal carotid artery with a saccular aneurysm measuring 17 × 16 × 14 mm extending into the parapharyngeal space. There was minimal atherosclerotic disease and an incidental bovine arch was noted (Fig. 1). Initially, she was considered for covered or flow diverting stenting by Interventional Radiology. However, concerns were raised regarding the ability of the stent to conform to the artery wall and the risk of kinking or thrombosis due to the severe internal carotid artery tortuosity. Therefore, she was considered for an open vascular repair. Given the lack of branches of the internal carotid artery requiring exposure or ligation, and the proximity of the inflow and outflow limbs at the base of the hairpin loop, the anatomy appeared amenable to direct end-to-end anastomosis for aneurysm exclusion. The patient underwent a standard longitudinal carotid exposure under general anaesthetic. The internal carotid artery was noted to have a ‘omega shaped’ bend with the apex of the artery and the aneurysm projecting medially and obscured from view, diving distally into the parapharyngeal space (Fig. 2). However, as the proximal and distal limbs of the aneurysm were easily opposable without tension, pursuing surgical exposure of the aneurysm itself was considered unnecessarily hazardous with increased risk of pharyngeal trauma. Furthermore, as the aneurysm was located at the distal internal carotid artery, the opportunity to avoid adjunctive manoeuvres for exposure and high dissection with potential cranial nerve injury was welcomed. The aneurysm was excluded by proximal and distal transection and a straight-forward end-end anastomosis of both limbs (Fig. 3). The remnant aneurysm was left to thrombose in-situ, however, given the lack of branches on the internal carotid artery, was not considered problematic. The remaining ends of the aneurysm were oversewn and a redundant piece of artery was sent for histology. The patient had an uncomplicated recovery. She was commenced on regular aspirin and discharged on post-operative day three. Histology was unremarkable, demonstrating normal muscular artery. At clinic follow up 3 months later, the wound was well healed and there were no focal neurologic deficits or evidence of cranial nerve injury. A duplex ultrasound demonstrated a patent right internal carotid artery. A tortuous internal carotid artery is a common incidental finding during carotid endarterectomy, however, severe tortuosity may cause cerebrovascular insufficiency when kinking of the artery occurs. The finding of an aneurysmal tortuous internal carotid artery, however, is uncommon. Extracranial carotid artery aneurysms are rare, representing <1% of all aneurysms and 0.1–2% of all carotid procedures. Atherosclerosis is the most common aetiology, but trauma, previous surgery, infection, radiation and fibromuscular dysplasia may also result in aneurysmal change.