Double-barrel extracranial–intracranial bypass surgery followed by endovascular carotid artery occlusion in a patient with an extracranial giant internal carotid artery aneurysm due to Ehlers–Danlos syndrome
A 42-year-old man with EDS type IV was admitted to our department with a rapidly progressive cervical pulsatile and painful swelling on the right side (). Apart from the swelling, a neurological examination also showed right-sided palsy of the hypoglossal nerve. The patient's history indicated that, in 1999, direct revascularization using a vessel graft to treat an extracranial giant aneurysm of the left ICA had failed due to technical problems in performing an adequate anastomosis causing left hemispheric ischemia. Neurological impairment such as right-sided hemiparesis or aphasia was not seen at the current presentation.\nCerebral digital subtraction angiography (DSA) showed a giant aneurysm of the right ICA (C1 segment) measuring 10×7×7 cm, extending from the carotid bifurcation to the base of the skull (). A largely dilated basal artery and left posterior communicating branch indicating compensatory supply to the left hemisphere was also demonstrated. A Doppler-controlled balloon occlusion test of the right ICA revealed a moderate insufficiency of the middle cerebral artery (MCA) territory and additional collateralization of the right hemisphere via the ophthalmic branches. MRI demonstrated ischemic lesions of the left hemisphere as a result of the previous occlusion of the left ICA.\nThe radiological findings were then thoroughly discussed in an interdisciplinary conference including neuroradiological, neurological and neurosurgical colleagues in order to achieve a low-risk and adequate treatment of the growing aneurysm of the right ICA. The agreed strategy consisted of securing right cerebral perfusion via flow redirection through a double-barrel extracranial–intracranial bypass followed by surgical trapping of the aneurysm. The double-barrel bypass was successfully placed from the superficial temporal artery to two M4 cortical branches of the right MCA (). Both branches showed sufficient flow in postoperative angiographic studies. Prior to definite occlusion, a temporary ICA occlusion test was conducted using an eclipse balloon in order to confirm sufficient contrast perfusion of the right hemisphere through the previously placed tandem bypass (). The occlusion test showed good flow through the bypass and additional ophthalmic collateral filling, so we were able to proceed with the permanent elimination of the aneurysm from the circulation. Surgical trapping of the aneurysm failed due to the risk of sacrificing the external carotid artery. A decision was therefore made to occlude the aneurysm by means of endovascular coiling. Two separate sessions were needed to occlude both the distal and proximal segments of the giant aneurysm. The distal segment was successfully occluded with platinum spiral coils (). A stent was then placed in the right external carotid artery to secure its patency and, from there, stent-supported coiling was performed to occlude the proximal segment (). Secure proximal placement of the coils was not possible in a single-catheter technique owing to the high flow turbulence within the aneurysm sac. By using a double-catheter method, two coils could be placed simultaneously directly outside the stent wall facing the proximal segment of the extracranial ICA. Immediately after the procedure the patient had a transient ischemic attack with latent left-sided hemiparesis which regressed within 48 h. Ischemic lesions were excluded in post-procedural non-enhancement CT scans. Minor surgery was later performed to drain the residual hematoma in the aneurysm sac. The bulging skin collapsed instantly, reducing the large visible swelling on the patient's neck. The patient recovered rapidly from the individual procedures without any additional impairment and was discharged in an unaltered clinical/neurological condition.\nFollow-up at 2 months revealed a good clinical result without any deficits with slight recurrence of the swelling on the right side of the neck. CT and CT angiography showed a hypodense non-enhancing filling of the remaining aneurysm sac. Density measurements indicated the filling to be serous fluid which was safely drained via CT-assisted puncture. Again the swelling collapsed immediately, leaving the patient with a good cosmetic result (). The patient died a year later due to a ruptured aneurysm of the splenic artery.