Abstract
Guidelines for the treatment of unruptured internal carotid artery anterior wall (dorsal) aneurysms (ICDAs) are yet to be discussed. Here, we report the clinical findings and outcomes of three surgically treated cases of unruptured ICDAs (1 case of the saccular type and 2 cases of the blister-like red wall type) and discuss the guidelines for treatment.
Case 1 was a 51-year-old woman who presented with transient visual field defects in the left eye. We diagnosed her with compression of the left optic nerve by an unruptured ICDA approximately 5 mm in diameter and subsequently scheduled an operation. Although we had planned to follow the guidelines for the surgical treatment of a ruptured ICDA (extracranial-intracranial [EC-IC] bypass + trapping), the aneurysm was found to be of the saccular type, and could be treated by neck clipping. After surgery, the patient no longer had visual field defects, and was discharged to return home with a modified Rankin Scale (mRS) for neurologic disability score of 0. No recurrence of aneurysms has been detected at 4 years post-surgery. Case 2 was an 84-year-old woman who presented with Hunt and Kosnik (H&K) grade 4 subarachnoid hemorrhage (SAH). We diagnosed her with a ruptured anterior communicating artery aneurysm. During emergency surgery, we found an unruptured ICDA of the blister-like red wall type on the right internal carotid artery. After clipping the ruptured aneurysm, we performed muscle wrapping of the ICDA. No growth of the ICDA was detected by three-dimensional-computed tomography angiography (3D-CTA) 1 month after surgery, and the patient was transferred to another hospital with an mRS score of 2. The ICDA has not ruptured at 3.5 years post-surgery. Case 3 was a 48-year-old woman who presented with H&K grade 3 SAH. We diagnosed a rupture of a left internal carotid-posterior communicating artery aneurysm. During emergency surgery, we found an unruptured ICDA of the blister-like red wall type on the left internal carotid artery. Similar to Case 2, after clipping the ruptured aneurysm, we performed muscle wrapping of the ICDA. The patient was discharged with an mRS score of 0. No growth of the aneurysm has been detected at 1 year post-surgery. ICDAs for which arterial dissection cannot be ruled out should be treated cautiously following the ruptured aneurysm treatment strategy, even if the aneurysm is unruptured. However, it may be possible to treat unruptured saccular type-ICDAs by clipping alone, similar to unruptured aneurysms located elsewhere. Moreover, muscle wrapping may be effective in preventing the growth and the rupture of unruptured blister-like red wall type ICDAs encountered incidentally during surgery, at least in the shortterm. Both treatment strategies need to be validated by more cases and longer follow-up periods.
