True Posterior Communicating Artery Aneurysm Associated With a Posterior Communicating Segment Aneurysm: A Case Report.

"True" posterior communicating artery (PComA) aneurysms are one of the rarest of all intracranial aneurysms. Diagnosis of this kind of aneurysm and treatment continue to be challenging for neurosurgeons because of the surrounding structures and their importance. Concomitant vascular anomalies, like dissections or hypoplasia, are frequently found with these aneurysms. Multiple aneurysms in the posterior communicating segment are even rarer than true PComA aneurysms alone. To achieve a safe clipping in patients with multiple aneurysms in this location, some coadjuvant maneuvers may be performed, like resection of the anterior part of the uncus. By presenting this case, we aim to show how we managed to treat these rare aneurysms with good outcomes for the patient and microsurgical resolution.  We present a representative case of a 50-year-old female with headache, nausea, language disturbances, left hemiparesis, and deterioration of consciousness, referred to our hospital with a diagnosis of subarachnoid hemorrhage (Hunt & Hess grade 3, Fisher grade 4) secondary to a rupture of a true PComA aneurysm. Urgent surgical clipping was performed, and during surgery, a junctional aneurysm and a true PComA aneurysm were found very close to each other, complicating the procedure, so to have more space to work and perform a safe clipping, we resected the anterior part of the uncus, which broadened the retrocarotid space, performing the clipping with complete exclusion of both aneurysms and no complications. The patient was discharged after five days with right partial III nerve palsy. Postsurgical CT angiography (CTA) and perfusion images showed the permeability of branches distal to the clips.  Knowledge of microsurgical and vascular anatomy is key to the successful treatment of this type of aneurysm, especially when we have multiple aneurysms so close to each other, like in this case, because of the relation with cranial nerves and perforators. Performing extra procedures or transurgical maneuvers like the anterior resection of uncus to broaden our working space is always helpful to avoid complications or major deficits.