Institutional experience using the endoscopic endonasal approach for the treatment of 40 intracranial aneurysms: indications, outcomes, and technical considerations

OBJECTIVE: The endoscopic endonasal approach (EEA) provides a ventral surgical corridor, which can be advantageous in the management of carefully selected cerebral aneurysms. The literature lacks large series to better delineate the indications and limitations of this technique. The aim of this study was to elucidate the technique's safety, indications, advantages, and limitations, as well as its evolution over time. METHODS: The clinical records of all patients with intracranial aneurysms treated via EEA at the authors' institution, from the unveiling of the technique in March 2005 to February 2025, were retrospectively reviewed. Patient-specific treatment indications, surgical results, and technical parameters were examined. RESULTS: The study cohort consisted of 40 aneurysms in 34 patients. Six patients had 2 aneurysms clipped during the same endonasal procedure, while 3 others had a sellar tumor excised concurrently. Seven patients initially presented with subarachnoid hemorrhage, and 4 had pseudoaneurysms. Anatomically, 29 aneurysms were situated in the paraclinoid or cavernous sinus region, 10 were in the posterior circulation, and 1 giant aneurysm involved the petrous and cavernous internal carotid artery. Surgical treatment was only considered if endovascular therapy was not thought to be appropriate by experienced endovascular specialists. EEA was chosen if it was perceived to be safer than an open approach in terms of obtaining proximal and distal control, reducing manipulation of cranial nerves or the brain, or for the treatment of concomitant sellar pathology. Four patients underwent EEA for mass effect, 2 after postcoiling recanalization, and 3 because of antiplatelet contraindication/intolerance. Postoperative complications included 8 patients experiencing CSF leaks, 3 meningitis, 2 clip exposure, 3 lacunar infarcts (2 causing mild disability), and 4 new cranial nerve palsies that either improved or resolved. There were no parenchymal contusions, venous infarcts, postoperative seizures, optic neuropathies, lower cranial nerve palsies, or procedure-related mortalities. In the latter series of 14 cases since 2019, complications were mainly CSF leaks, with no long-term effects. During an average follow-up of 62.6 months, 1 patient required retreatment with a flow diverter. CONCLUSIONS: The ventral surgical corridor afforded by EEA is a valuable option for the surgical treatment of carefully selected paraclinoid internal carotid artery and posterior circulation aneurysms arising medial to the cranial nerves, particularly when endovascular options are restricted. EEA may result in decreased morbidity related to cranial nerve deficits and parenchymal injury compared with lateral approaches. However, CSF leaks remain the main limitation, especially after subarachnoid hemorrhage.