Cranial Nerve Injury in Endoscopic Endonasal Approach to Skull Base Surgery: A Systematic Review

The endoscopic endonasal approach (EEA) to the skull base has revolutionized management of ventral skull base lesions, offering superior visualization and reduced morbidity. Yet, iatrogenic cranial nerve (CN) injuries, causing temporary or permanent deficits, remain a key, underexplored complication that significantly affects quality of life. This systematic review describes the prevalence of CN injuries in EEA and the evidence on prevention and management strategies. Following PRISMA guidelines, we searched MEDLINE Embase, Web of Science, and the Cochrane Library, resulting in 5453 studies ( https://duke.is/search ). Dual, independent screening of titles/abstracts was performed, followed by full-text screeningl.. Studies were included if they investigated CN injury in any EEA to skull base surgery, if they explicitly stated that the CN injury occurred as a result of surgery and was not attributable to the underlying pathology, and if they reported a worsening of a pre-existing CN injury following surgery. Studies were excluded if the CN injury was present prior to surgery and remained unchanged postoperatively, if study was not published in English or if it was conducted on cadavers or animal models. 177 studies were included for review. Across 18,546 patients, 859 CN injuries were reported. The abducens (24.4%), optic (23.7%), and olfactory (18.6%) nerves were most affected, linked primarily to pituitary adenomas (34.49%) and sellar approaches (34.4%). Full recovery occurred in 38.4% of cases, while 29.9% had permanent deficits. Intraoperative neuromonitoring (EMG, VEPs) was reported in 34 studies, showing prognostic value but lacking definitive evidence for injury prevention. Only 5% of studies addressed postoperative management, highlighting a care gap. This review stresses the need for standardized reporting, enhanced monitoring and robust postoperative strategies to optimize EEA outcomes. Future directions include prospective studies and patient-reported outcomes to refine skull base surgery safety. Fig. 1 Injury by Nerve, Pathology, and Approach Fig. 2 Cranial Nerve Injury by Approach Fig. 3 Cranial Nerve Injury by Pathology Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany