Background:The surgical treatment of complex intracranial aneurysms (CIAs) represents a significant challenge to the skill and expertise of the neurosurgeon. The natural history of complex cerebrovascular lesions is especially unfavorable because of the pressure effect on adjacent areas, the risk of embolism in the presence of intraluminal thrombi, and the possibility of hemorrhage through leakage or rupture of the aneurysm. The surgical strategy must be customized for each case in order to maximize the treatment effectiveness and the safety of the patient.Case Description:A 68-year-old woman presented with a 10-month history of atypical headaches but no other neurological symptoms. Computed tomography scan and digital subtraction angiography revealed an unruptured saccular aneurysm on the M1 segment of the right middle cerebral artery. The lesion was 21 mm in length in its largest diameter and with an undefined neck (extensive involvement of the walls of the afferent vessel). Craniotomy was performed in order to expose the lesion and allow microsurgical dissection of the neck of the aneurysm and its adjacent structures. A balloon catheter was navigated via the internal carotid artery to a position alongside the aneurysm neck. With the balloon fully inflated, the aneurysm was punctured and drained, and a guide clip was located at the neck of the aneurysm. Additional clips were applied using a similar procedure to ensure the exclusion of the aneurysm.Conclusion:The patient recovered without complications and complete occlusion of the CIA was confirmed on follow-up angiography. A modified Rankin score of 0 was attributed to the patient 6 months after treatment. A multidisciplinary perspective is important in planning and executing the treatment of CIAs.