Can Ophthalmologic Examination Predict Abducens Nerve Recovery After Endoscopic Skull Base Surgery?

Objectives: While abducens nerve palsy (ANP) is a known risk in the setting of some endoscopic endonasal skull base surgery (ESBS), frequency and prognosis of post-operative palsy remain unknown. Our goals were to determine the frequency and prognosis of ANP after high-risk ESBS, and identify factors associated with recovery. Methods: Retrospective case series of all patients with pathology at highest risk for abducens nerve injury (pituitary adenoma, chordoma, meningioma, chondrosarcoma, cholesterol granuloma) generated a list of patients with abducens nerve palsy after ESBS performed from 2011–2016. A validated ophthalmologic clinical grading scale measuring lateral rectus duction from 0 to −5 (full motion to inability to reach midline) was measured at multiple time points to assess recovery of ANP. Results: Of 655 patients who underwent ESBS with increased risk of abducens injury, 40 (6.1%) post-operative palsies were identified and 39 patients with dedicated examination at multiple time points were included in subsequent analysis. Complete resolution was noted in 25 patients (64%) within 12 months. While 19 of 23 (83%) with a partial palsy had complete resolution, only six of 16 (38%) with a complete palsy resolved entirely (P =.005; Fisher's exact test). All six patients with delayed onset of palsy resolved (P =.070; Fisher's exact test). Meningioma and chordoma had higher rates of both temporary and permanent post-operative ANP (P <.0001; Fisher's exact). Conclusions: The frequency of post-operative ANP following ESBS is low, even in high-risk tumors. While only a minority of complete abducens nerve palsies recover, patients with partial or delayed palsy post-operatively are likely to recover function without intervention. Level of Evidence: IV Laryngoscope, 131:513–517, 2021.