Predictors of Recurrence After Sub-total or Near-total Resection of Vestibular Schwannoma: Importance of Tumor Volume and Ventral Extension.

OBJECTIVE: To evaluate the predictors of remnant tumor regrowth and need for salvage therapy after less than gross total resection (GTR) of vestibular schwannoma (VS). STUDY DESIGN: Retrospective chart review. SETTING: Tertiary neurotologic referral center. PATIENTS: Patients who underwent VS resection between 2008 and 2019 either with GTR, near total resection (NTR), and subtotal resection (STR). INTERVENTIONS: Microsurgical resection, salvage radiosurgery. MAIN OUTCOME MEASURES: Regrowth free interval, salvage free interval, tumor doubling rate. RESULTS: Three hundred eighty five cases (GTR = 236, NTR = 77, and STR = 71) from 2008 to 2019 were included. STR cohort had much larger and complex tumors with significant differences in tumor volume, ventral extension and brainstem compression (p  < 0.001). On single predictor analysis, tumor volume, ventral extension, brainstem compression as well as STR strategy was associated with significant increased risk of regrowth and need for salvage therapy. Multivariate analysis revealed STR strategy as significant predictor of regrowth (hazard ratio 3.79, p  < 0.0005). Absolute remnant volume and extent of resection (EOR) did not predict regrowth. A small proportion of cases (NTR = 4%, STR = 15%) eventually needed salvage radiosurgery with excellent ultimate local tumor control with no known recurrence to date. CONCLUSIONS: Conservative surgical strategy employing NTR or STR can be employed safely in large and complex VS. While there is increased risk of regrowth in the STR cohort, excellent local control can be achieved with appropriate use of salvage radiosurgery. No disceret radiologic or operative predictors of regrowth were identified.

Development and validation of an endoscopic ear surgery classification system.

OBJECTIVES/HYPOTHESIS: To design and validate a classification system for endoscopic ear surgery. STUDY DESIGN: Validation study. METHODS: A classification system was devised that quantifies use of the endoscope during middle ear surgery. Otologic operative reports were reviewed by attending surgeons and trainees. A power analysis was performed to determine number of cases needed to review. The following categories were used: class 0 is defined by using the microscope only; class 1 describes the use of endoscope for inspection without dissection; and class 2 describes mixed use of the endoscope and the microscope. It is further subdivided into 2a and 2b, where the endoscope is used for less than 50% of dissection and more than 50% of dissection, respectively. Class 3 describes the use of the endoscope for the entire surgery. Fifty cases were reviewed by three attending otologic surgeons, one resident, and one medical student. RESULTS: Weighted Cohen's Kappa for inter-rater agreement between the two institutional surgeons was 0.79 (95% bias corrected [BC] confidence interval [CI]: 0.58-0.93). Agreement between the external surgeon and the two institutional surgeons was 0.77 (95% BC CI: 0.58-0.89) and 0.76 (95% BC CI: 0.57-0.88). Weighted Kappa between institutional surgeons and a resident was 0.73 (95% BC CI: 0.53-0.88) and 0.62 (95% BC CI: 0.38-0.80), and between institutional surgeons and a medical student was 0.75 (95% BC CI: 0.56-0.89) and 0.70 (95% BC CI: 0.49-0.85). CONCLUSIONS: There was substantial inter-rater agreement. This classification system can be used as a simple and reliable tool to describe the extent to which an endoscope was used during ear surgery. LEVEL OF EVIDENCE: NA. Laryngoscope, 128:967-970, 2018.