OBJECTIVE Detection of vestibular schwannoma (VS) growth during observation leads to definitive treatment at most centers globally. Although ≥ 2 mm represents an established benchmark of tumor growth on serial MRI studies, 2 mm of linear tumor growth is unlikely to significantly alter microsurgical outcomes. The objective of the current work was to ascertain where the magnitude of change in clinical outcome is the greatest based on size. METHODS A single-institution retrospective review of a consecutive series of patients with sporadic VS who underwent microsurgical resection between January 2000 and May 2020 was performed. Preoperative tumor size cutpoints were defined in 1-mm increments and used to identify optimal size thresholds for three primary outcomes: 1) the ability to achieve gross-total resection (GTR); 2) maintenance of normal House-Brackmann (HB) grade I facial nerve function; and 3) preservation of serviceable hearing (American Academy of Otolaryngology–Head and Neck Surgery class A/B). Optimal size thresholds were obtained by maximizing c-indices from logistic regression models. RESULTS Of 603 patients meeting inclusion criteria, 502 (83%) had tumors with cerebellopontine angle (CPA) extension. CPA tumor size was significantly associated with achieving GTR, postoperative HB grade I facial nerve function, and maintenance of serviceable hearing (all p < 0.001). The optimal tumor size threshold to distinguish between GTR and less than GTR was 17 mm of CPA extension (c-index 0.73). In the immediate postoperative period, the size threshold between HB grade I and HB grade > I was 17 mm of CPA extension (c-index 0.65). At the most recent evaluation, the size threshold between HB grade I and HB grade > I was 23 mm (c-index 0.68) and between class A/B and C/D hearing was 18 mm (c-index 0.68). Tumors within 3 mm of the 17-mm CPA threshold displayed similarly strong c-indices. Among purely intracanalicular tumors, linear size was not found to portend worse outcomes for all measures. CONCLUSIONS The probability of incurring less optimal microsurgical outcomes begins to significantly increase at 14–20 mm of CPA extension. Although many factors ultimately influence decision-making, when considering timing of microsurgical resection, using a size threshold range as depicted in this study offers an evidence-based approach that moves beyond reflexively recommending treatment for all tumors after detecting ≥ 2 mm of tumor growth on serial MRI studies.

Objective: Previous research has shown that tumor growth during observation of small-to-medium sized sporadic vestibular schwannomas (VSs) occurs almost exclusively within 3 to 5 years following diagnosis. This has led some to consider ending surveillance after this interval. This study seeks to characterize a cohort of patients with tumors that exhibited late growth. Study Design: Retrospective cohort study. Setting: Tertiary referral center. Patients: Adults with sporadic VSs who initially elected observation with serial magnetic resonance imaging (MRI) surveillance. Intervention(s): None. Main Outcome Measure(s): Linear tumor growth was measured in accordance with AAO-HNS reporting guidelines. Delayed growth was defined as growth ≥2 mm in linear diameter that was first detected 5 years or more from the initial MRI. Results: From a total of 361 patients, 172 experienced tumor growth during the interval of observation. Fourteen of these 172 patients (8.1%) experienced late growth occurring at 5 years or beyond. Among patients with delayed growth, the fastest growth rate after extended quiescence was 1.33 mm/yr, and the longest delay before tumor growth detection was 11.1 years. Additional treatment was recommended for six (42.9%) of the patients with delayed growth. Of 68 tumors that remained in the IAC, 11 (16.2%) demonstrated delayed growth. Of 66 tumors that presented in the CPA, 2 (3.0%) demonstrated delayed growth. Initial size was larger for tumors demonstrating early growth compared with those with delayed growth. For tumors within the IAC, those with early growth had a significantly higher median growth rate than those with delayed growth (1.40 vs. 0.45 mm/yr, p < 0.001). Conclusions: Delayed growth encompassed 8.1% of growing VSs and 3.9% of all observed tumors. Patients with delayed growth exhibited slower growth rates compared with those who were diagnosed with growth early in their observation course. These findings support the need for lifelong surveillance of untreated VSs given the possibility of clinically significant delayed growth. Increasing the time interval between MRI studies after 5 years is a reasonable concession to balance practicalities of cost and convenience with risk of delayed of tumor growth.

Objective: To assess vestibular schwannoma (VS) practice patterns among providers. Study Design: Cross-sectional survey. Setting: 8th Quadrennial International Conference on Vestibular Schwannoma and Other CPA Tumors. Subjects: Clinicians who specialize in the management of VS. Main Outcome Measures: Responses to questions on the management and anticipated outcomes of VS for a series of common clinical scenarios were compared by specialty (otolaryngology versus neurosurgery), level of experience, scope of practice (surgery versus radiation and surgery), and geographic location of practice (United States versus international). Results: Responses from 110 participants were analyzed. Overall, 53% of respondents were otolaryngologists, 60% had greater than 10 years of experience, and 57% practiced within the United States. In total, 86% of respondents would pursue initial observation for themselves if diagnosed with a 4 mm distal intracanalicular VS; however, practicing radiosurgeons were more likely to select stereotactic radiosurgery for this scenario compared with providers who solely practice surgery (14 versus 0%; p = 0.032). Otolaryngologists and neurosurgeons alike report that radiosurgery should not be considered a long-term hearing preservation strategy. Otolaryngologists were more optimistic regarding microsurgical hearing preservation outcomes for small distal intracanalicular tumors compared with neurosurgeons (11 versus 3% selected a high likelihood of maintaining class A/B hearing; p = 0.007). Ninety-five percent of respondents prioritized facial nerve outcome over complete disease removal in the context of microsurgical resection of large tumors. Conclusions: Management decision-making and expected outcomes for various clinical scenarios were largely similar among providers; however, variances in several key clinical areas exist. This study points to the feasibility of developing a widely accepted consensus statement among VS experts across specialties.

Objective This study sought to determine whether a history of pregnancy or bilateral oophorectomy is associated with subsequent otosclerosis development or disease severity. Study Design Population-based case-control study. Setting Olmsted County, Minnesota. Methods Women diagnosed with otosclerosis were matched to 3 women without otosclerosis based on age and historical depth of medical records. Associations of prior delivery and bilateral oophorectomy with subsequent development of otosclerosis and with pure-tone average (PTA) at the time of otosclerosis diagnosis were evaluated. Results We studied 1196 women: 299 cases of otosclerosis and 897 matched controls. The odds ratio for the association of ≥1 delivery with otosclerosis was 1.16 (95% confidence interval [CI] 0.85-1.60; P = .35). Odds ratios for the associations of 1, 2, 3, or ≥4 deliveries with otosclerosis were 1.22 (0.83-1.80), 1.09 (0.71-1.68), 1.28 (0.77-2.12), and 1.00 (0.54-1.84), respectively. The odds ratio for the association of prior bilateral oophorectomy with otosclerosis was 1.12 (0.58-2.18; P = .73). In cases with otosclerosis, PTA at diagnosis was not significantly higher for women with ≥1 delivery as compared with those without (median 45 dB hearing loss [HL] [interquartile range {IQR} 36-55] vs 43 [IQR 34-53]; P = 0.18) but was significantly higher for women with bilateral oophorectomy compared with those without (median 54 dB HL [IQR 44-61] vs 44 [IQR 34-53]; P = .03). Conclusion These data do not support a relationship between endogenous estrogen exposure and development of otosclerosis. Women with otosclerosis who had a history of pregnancy did not have significantly worse hearing at the time of diagnosis, suggesting that pregnancy is not associated with disease severity.

The present data suggest a small effect of posterior fossa size on some clinical outcomes in medium sized vestibular schwannomas.