Middle Cerebral Artery Bifurcation Aneurysm: Incidental Aneurysm, Uneventful Microsurgical Clipping, Delayed Symptomatic Vasospasm, Treated with Short-Term Intra-arterial Infusion of Milrinone, Followed by Continuous Local Intra-arterial Nimodipine Infusion, and Recurrent Generalized Epileptic Seizures

Abstract

A 63-year-old man, otherwise healthy apart from arterial hypertension, underwent a cranial MRI and MRA examination as a work-up for occasional migraine headache. MRA demonstrated aneurysms at the bifurcation of the right and left middle cerebral artery (MCA). A subsequently performed diagnostic DSA examination confirmed both wide-necked aneurysms. The fundus diameter of the right aneurysm was 6 mm and of the left aneurysm 3 mm. The decision was made to first clip the smaller left aneurysm, since the reconstruction of the right MCA bifurcation would most likely require a stent-assisted coiling with associated dual-platelet function inhibition. The left MCA aneurysm underwent microsurgical clipping, which was accomplished without any issues. A routine DSA examination 2 days after surgery confirmed the complete exclusion of the aneurysm from blood circulation by the applied clip. No vasospasm was present. The patient was discharged home without neurological deficit. He was readmitted 19 days after the surgery with fluctuating aphasia, paresthesia of the right hand, and no hemiparesis. CT upon admission showed the expected postoperative changes. DSA revealed severe vasospasm of the left M2 segments and of the opercular MCA branches. The short-term intra-arterial infusion of 8 mg milrinone into the left internal carotid artery (ICA) over 30 min on the 20th day after surgery reduced the vasospasm but failed to improve the clinical condition of the patient. Since the clinical condition did also not improve after a blockade of the stellate ganglion, the decision for a continuous local intra-arterial infusion of nimodipine was made on the 21st day after surgery. DSA 2 days later (the 24th postoperative day) showed a significant regression of the vasospasm, and the IA infusion of nimodipine was terminated. During the following days, the aphasia improved considerably. However, recurrent generalized epileptic seizures occurred on the 26th postoperative day. MRI was performed 4 days after the IA infusion of nimodipine had been terminated and showed a slightly increased signal intensity and a faint contrast enhancement of the left insular cortex. The seizures were well controlled by high-dose anticonvulsant medication. The patient remained intubated and was transferred for weaning and rehabilitation to another institution 37 days after the surgical clipping and 16 days after the onset of vasospasm. The occurrence and management of cerebral vasospasm after the microsurgical clipping of unruptured intracranial aneurysms are the main topics of this chapter.