2026 Poster Presentations
P501: POTENTIAL BIAS IN FACIAL NERVE OUTCOME REPORTING AFTER VESTIBULAR SCHWANNOMA SURGERY: A SYSTEMATIC REVIEW
Aidan Vanek, BS1; Keaton Snyder, BS1; Lauren Michelle, MD, MBA1; Erin Ling, BS, BA2; Kevin Quinn, MD1; Desi Schoo, MD1; 1Department of Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA; 2The Ohio State University College of Medicine, Columbus, OH, USA
Introduction: Facial nerve function, along with hearing and balance outcomes, is one of the three key outcomes after surgery for resection of vestibular schwannoma (VS). While post-operative hearing and balance outcomes are often measured objectively and with patient-reported outcomes, facial nerve outcomes are typically assessed by the surgical team using clinician-rated scales such as the House-Brackmann (HB) system, the Sunnybrook scale, and eFace. Because these metrics have a degree of subjectivity, they may introduce bias. The primary aim of this study was to review published literature and characterize how facial nerve outcomes are reported, with a secondary aim of identifying the type of personnel responsible for grading.
Objective: Report on the current standards used to describe facial nerve outcomes after resection of vestibular schwannoma.
Methods: A PubMed search was conducted in September 2025, including studies over the past 10 years that reported facial nerve outcomes after VS surgery. Fifty-three papers resulted, and 25 met criteria for inclusion. Data extracted included years of publication, surgery type, facial nerve rating scale, and person responsible for grading.
Results: All 25 studies used the HB scale, with three also reporting intraoperative EMG results. Nineteen (76%) papers did not specify who graded patients, three (12%) reported surgeon self-assessment, and three (12%) used blinded independent reviewers. None of the studies used objective measurement tools.
Conclusion: Most studies reporting on facial nerve outcomes after VS surgery rely on clinician-rated scales, without specifying the evaluator, which introduces a risk of self-assessment bias. Just 3 of the 25 studies utilized a blinded reviewer, and none incorporated objective measures. When reporting on facial nerve outcomes, skull base surgeons should consider implementing advancements in machine learning and artificial intelligence to objectively quantify the outcome and decrease the risk of bias.