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 the management of ventral skull base lesions, offering superior visualization and reduced morbidity. Yet, iatrogenic cranial nerve (CN) injuries, causing temporary or permanent deficits, remain an underexplored complication that significantly affects quality of life. This systematic review describes the number of reported cases of CN injuries in EEA and the evidence on prevention and management strategies. Following PRISMA-SR guidelines, we searched Medline, Embase, Web of Science, and the Cochrane Library, and screened 2796 studies; 177 were included. 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 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 emphasizes 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.