A Case of Posterior Communicating Artery Aneurysm Combined With an Atypical Origin of the Ipsilateral Ophthalmic Artery

Abstract

Objective: Anatomy of the ophthalmic artery (OA) is of great practical importance in surgery for anterior circulation aneurysms. In most cases, the OA arises from the supraclinoid segment of the internal carotid artery (ICA) and enters the orbit through the optic canal inferolaterally to the optic nerve. The OA arising from the anterior cerebral artery (ACA) and entering the optic canal above the optic nerve is extremely rare.Clinical case: We report a case of a 29-year-old female patient admitted to Scientific Research Institute – Ochapovsky Regional Clinical Hospital No. 1 (Krasnodar, Russian Federation) with a ruptured true aneurysm of the left posterior communicating artery (PCoA) and an abnormal origin of the OA from the ACA. The disease manifested itself as ischemic stroke in the basal ganglia on the left causing diagnostic difficulties during initial hospitalization. Cerebral angiography confirmed a PCoA aneurysm and origin of the OA from the ipsilateral ACA. During surgery the neck of the aneurysm was clipped, and the aneurysm dome was opened to control the extent of clipping and remove thrombotic masses. During their removal, hemorrhage appeared from the posterior pole of the aneurysm. During the exploration it was found that the aneurysm was a dilated PCoA connecting the right ICA with the right posterior cerebral artery (PCA). A thrombosed anterior thalamoperforating artery emerged from the superior surface of the dome, and its junction with the precommunicating segment of the right PCA was detected in the region of the posterior pole of the aneurysm. The second clip was placed at the communication site between the aneurysm and the right PCA. The patient was discharged in satisfactory condition with a stable neurological status.Conclusions: The combination of abnormal anatomy of arteries at the base of the brain and cerebral aneurysms increases the risk of tactical errors and perioperative complications. Each such case requires a careful comparison of the clinical, imaging, and intraoperative findings. In the presented case of the patient with the ruptured rare PCoA aneurysm, the disease manifested atypically due to the partial thrombosis of the aneurysm and hemorrhage into the aneurysmal wall. The imaging findings revealed lacunar stroke in the thalamoperforating artery basin and an ICA aneurysm with no signs of subarachnoid hemorrhage. During the surgery the aneurysm was initially regarded as typical saccular. The opening of the dome and removal of all thrombotic masses made it possible to determine the eccentric fusiform nature of the aneurysm, perform its radical exclusion, and prevent fatal hemorrhage in the postoperative period.