Staged Surgical and Endovascular Treatment of a Giant Serpentine Basilar Artery Aneurysm: Case Report
Paul J. Apostolides, MD
Michael T. Lawton, MD
Jeff W. Chen, MD, PhD†
John McKenzie, MD‡
Robert F. Spetzler, MD
Division of Neurological Surgery, ‡Barrow Neurological Institute, Mercy Healthcare Arizona, Phoenix, Arizona
Current Address: †University of Texas, Medical Branch at Galveston, Texas, ‡Baptist Hospital, Jacksonville, Florida
A giant serpentine artery arising from the trunk of the basilar artery is treated successfully with staged surgical and endovascular therapy. Giant aneurysms sometimes demand a combination of surgical and endovascular techniques for successful management. This case represents the first report of a giant serpentine basilar artery aneurysm treated with staged intracranial-extracranial bypass and permanent basilar artery occlusion using a detachable balloon. The patient enjoyed a good long-term functional outcome.
Key Words: balloon occlusion, basilar artery, cerebral revascularization, endovascular therapy, extracranial-intracranial bypass, giant serpentine aneurysm, subarachnoid hemorrhage
The surgical management of giant serpentine aneurysms of cerebral vessels remains a complex and challenging problem for neurosurgeons. Definitive treatment of these lesions often requires alternative (nonclip) techniques because their location, large size, or lack of a discrete neck prohibits either direct surgical approach or conventional clipping.[3-5,21,24] We report the successful treatment of a giant serpentine aneurysm arising from the trunk of the basilar artery using staged surgical and endovascular therapy.
Figure 1. (A) Axial computed tomography scan of the posterior fossa with intravenous contrast agent. Calcification is visible. The rim of enhancement corresponds to the aneurysmal wall and serpiginous lumen. (B) Coronal and (C) sagittal T1-weighted magnetic resonance images of the giant serpentine aneurysm. The heterogeneous nature of the aneurysmal contents suggests the presence of thrombus of different ages.
A 45-year-old right-handed male with long-standing, poorly controlled hypertension presented with a 1-year history of progressive left-sided weakness, dysarthria, and gait difficulty. The patient''s physical examination was remarkable for bilateral endgaze nystagmus on far lateral gaze, a left pronator drift, and 4/5 strength of the left upper and lower extremities. He demonstrated left-sided dysmetria and dysdiadochokinesia and had a positive Romberg'' s sign. He had 3+ reflexes and an upgoing toe on the left and was ambulatory with the assistance of a cane.
A computed tomography scan of the head demonstrated a 3.5- to 4.0-cm diameter calcified lesion with an isointense central region in the posterior fossa that was causing significant brain stem compression and hydrocephalus (Fig.1A). A peripheral rim of enhancement was seen after the administration of intravenous contrast agent. T1-weightedaxial, coronal, and sagittal magnetic resonance images revealed a 3.5- to 4.0-cm diameter lesion with heterogenous signal characteristics. A flow void was clearly visible within the lesion (Fig. 1B and C).
Figure 2. (A and B) Anteroposterior sequential subtraction and (C) lateral angiograms of the vertebral artery demonstrating the slow filling of the giant serpentine aneurysm.
Cerebral angiography (Fig. 2A, B, and C) revealed a giant aneurysm arising from the basilar trunk between the anterior inferior cerebellar arteries (AICAs) and the superior cerebellar arteries. The contrast agent entered the aneurysm just distal to the AICAs, ascended, followed a serpentine course to the patient''s right, and returned to the midline joining the basilar artery just below the level of the superior cerebellar arteries. A distinct aneurysmal neck was not visible, and the flow through the serpentine channel was sluggish. There was nocollateral filling of the posterior circulation via the posterior communicating arteries.
Figure 3. (A) Left lateral digital subtraction angiogram of the common carotid artery demonstrating the patent superficial temporal artery-to-superior cerebellar artery bypass (arrow). (B) Anteroposterior and (C) lateral digital subtraction angiograms of the vertebral artery demonstrating the markedly decreased flow through the aneurysm.
The patient first underwent a left-sided superficial temporal artery-to-superior cerebellar artery bypass (Stage1). A ventriculostomy was placed at surgery and later converted to a ventriculoperitoneal shunt. Postoperative angiography of the left common carotid artery demonstrated a patent bypass with good filling of the superior cerebellar artery (Fig. 3A). A vertebral artery injection showed marked reduction of contrast agent flowing through the aneurysmalsac (Fig. 3B and C).