Clinical Characteristics and Risk Factors of Delayed Ophthalmoplegia Following Cavernous Sinus Exploration in Endoscopic Skull Base Surgery Delayed transient ophthalmoplegia

Purpose: Postoperative cranial nerve dysfunction remains a significant concern in endoscopic endonasal surgery for pituitary neuroendocrine tumors (PitNETs), also known as a pituitary adenoma, that have invaded the cavernous sinus, but the incidence, timing, and recovery patterns vary widely across reports. This study aimed to characterize the clinical features, risk factors, and recovery patterns of patients with postoperative ophthalmoplegia following cavernous sinus exploration. Methods: We retrospectively analyzed 127 consecutive patients who underwent endoscopic skull base surgery with cavernous sinus exploration between March 2020 and September 2024. Ophthalmoplegia onset, affected cranial nerves, and prognosis were evaluated. Risk factors were assessed using multivariable logistic regression, and recovery patterns were analyzed using Kaplan‒Meier curves. Results: The overall gross total resection rate was 74.8% (96.9% for functioning adenomas), with 96.9% biochemical remission in functioning PitNETs at 3-month follow-up. New cranial nerve dysfunction occurred in 13.6% (17/125), manifesting exclusively as ophthalmoplegia. The abducens was most frequently affected nerve (52.9%), followed by the oculomotor (41.2%) and trochlear nerves (11.8%). Early onset (≤3 days) occurred in 29.4%, while delayed onset (>3 days) occurred in 70.6% of cases (mean onset: 9 days). Extensive hemostatic agent use (≥3 applications) (OR 15.57, p<0.001) and lateral compartment involvement (OR 9.00, p=0.011) were significant risk factors. Complete resolution occurred in 94.1% with median duration of 20 days. Conclusions: Postoperative ophthalmoplegia following cavernous sinus exploration occurs more frequently than previously reported but follows a benign course with near-complete resolution.. The distinct temporal patterns and risk factors suggest different pathophysiological mechanisms for early- versus delayed-onset ophthalmoplegia, guiding surgical decisions and patient counseling.