The Extended Endoscopic Endonasal Approach for the Treatment of Intracranial Aneurysms: Indications, Technical Nuances, and Results Gleaned from Two Decades of Clinical Experience

Objective: The advancement of the endoscopic endonasal approach (EEA) and its extension in the sagittal and coronal planes have broadened its applications beyond tumor pathologies. The ventral operative perspective offered by this approach can even facilitate the management of lesions, such as cerebral aneurysms, that were previously considered unapproachable through the endonasal route. In this report, we present our clinical experience to elucidate the indications and limitations of this innovative yet debated technique.

Method: To perform this study, we retrospectively reviewed the clinicoradiological records of all consecutive patients who underwent EEA for aneurysm clipping in our institution, from the introduction of the technique in 2005 until April 2024. Treatment indications, surgical outcomes, and technical insights were meticulously examined.

Results: The analysis identified a total of 30 patients (25 females), with an average age of 52 years. Six of them had two aneurysms clipped in the same endoscopic procedure, while 3 had a concomitant sellar tumor resected in the same setting. This resulted in 36 aneurysms being treated, out of whom 7 were ruptured, 4 were pseudoaneurysms, 26 were situated in the paraclinoid or cavernous sinus region ([Fig. 1]), 9 in the posterior circulation and 1 in the petrous carotid artery. In two instances a staged endovascular and endoscopic procedure was opted for to secure the aneurysm, whereas in another one a combined open and endoscopic approach was performed for proximal and distal control. Two patients underwent EEA after post-coiling reperfusion, 3 because of mass effect, whereas in 14 either endovascular treatment was not deemed ideal due to the aneurysm morphology or there was a relative contraindication for antiplatelet treatment. Regarding the postoperative complications, 7 patients sustained cerebrospinal fluid leak, 3 meningitis, 2 clip exposure, 3 stroke with one resulting in mild disability, and 3 cranial nerve palsies that either improved or completely resolved. No mortalities directly attributable to the surgical approach were noted. During a mean follow-up time interval of 64 months, a residual aneurysm of questionable significance was identified in four cases, all of which were monitored closely without requiring retreatment, except for one patient who was treated with a pipeline device.

Fig. 1 Intraoperative photographs and imaging findings of a right superior hypophyseal aneurysm treated via the extended endoscopic endonasal approach.

Conclusion: The advantageous ventral surgical corridor provided in EEA can facilitate the treatment of select intracranial aneurysms, due to factors such as bilateral presentation, proximity to the midline, accompanying sellar pathology, or intolerance to antiplatelet therapy. However, cerebrospinal fluid leaks, limited revascularization options, and reconstructive challenges represent major limitations of the technique.