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Objective:1) To compare vestibular schwannoma maximum linear dimensions and calculated volume with measured volume in accurately determining tumor volume and growth. 2) To determine natural growth history of vestibular schwannomas utilizing volumetric measurements in an observed patient population.Study Design:Retrospective chart review.Setting:Tertiary academic referral.Patients:One hundred fifty two adults with a vestibular schwannoma who underwent observational management with sequential magnetic resonance imaging (MRI) scans (496 scans).Intervention:MRI scans.Main Outcome Measures:Tumor volume calculated from linear dimensions compared with measured volume. The percentage change in tumor size (linear or volume) between consecutive MRI scans.Results:The percentage change in tumor size between consecutive MRIs is significantly different between maximum linear dimension (MLD) and measured tumor volume (p = 0.03), but no difference exists in the percentage change between measured and calculated tumor volume (p = 0.882 for three linear measurements, p = 0.637 for two linear measurements). The overall number of growing tumors is 57.2% (n = 87) with an average growth rate of 62.6%. If a criterion for growth of 20% change is used, 32.2% of tumors monitored by linear volume would have demonstrated growth while 57.2% of tumors with measured volume demonstrated growth.Conclusion:Maximum linear dimensions are a significantly less sensitive measure of tumor growth compared with measured volumes. Calculated tumor volume utilizing three linear measurements is an accurate predictor of both measured tumor volume and tumor growth.

Objective: Evaluate the incidence of cerebrospinal fluid leak following vestibular schwannoma surgery for mesh cranioplasty closure versus periosteal closure in the translabyrinthine approach. Determine nonsurgical variables associated with higher rates of cerebrospinal fluid leak following vestibular schwannoma surgery. Study Design: Retrospective chart review. Setting: Tertiary academic referral center. Patients: One hundred thirty-two patients with adequate documentation who underwent sporadic vestibular schwannoma resection via a translabyrinthine approach between 2000 and 2019. Intervention: Translabyrinthine excision of vestibular schwannoma with mesh cranioplasty closure or watertight periosteal closure. Main Outcome Measures: Primary outcome measures included the incidence of postoperative cerebrospinal fluid leak, total length of hospital stay (including the initial hospital stay as well as hospital days during any readmission within 30 days), and total operative time.Results: Our overall cerebrospinal fluid leak rate was 9.1% with a leak rate of 12.8% in our translabyrinthine titanium mesh closure group and 0% in our translabyrinthine periosteal closure. There was no statistically significant effect of age, body mass index, or size of tumor on the incidence of cerebrospinal fluid leak. There was also no statistically significantly difference between the two groups on length of operative time or number of days spent in the intensive care unit. Conclusion: Mesh cranioplasty is not a prerequisite for achieving a low cerebrospinal fluid leak rate following translabyrinthine approach for vestibular schwannoma resection. In our series, a significantly lower cerebrospinal fluid leak rate was demonstrated with the periosteal closure.

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Objective: Management of small vestibular schwannomas has evolved to where observation with interval imaging is an accepted treatment strategy. Loss of residual hearing is a known complication of observation. Magnetic resonance imaging (MRI) may provide critical information to assist in determining which tumors are at highest risk of hearing loss. We wished to determine what effect fundal cap size and cochlear fluid-attenuated inversion recovery (FLAIR) signal had on the progression of hearing loss in a large cohort of observed subjects. Study Design: Retrospective chart review. Setting: Tertiary academic referral center. Patients: Three hundred ninety-three adults with a vestibular schwannoma who underwent expectant management with serial audiograms and MRI. Interventions: Audiogram and MRI. Main Outcome Measures: Hearing outcomes included pure-tone average and word discrimination score (WRS). Cochlear FLAIR signal was measured as a ratio between the affected and nonaffected cochlea. Cerebrospinal fluid fundal cap was measured from the most lateral aspect of the tumor to the fundus of the internal auditory canal. Results: An increased cochlear FLAIR ratio was associated with a worse initial WRS (p = 0.0001, β=−0.25). A multivariate regression analysis demonstrated the variables fundal cap and initial WRS to significantly predict change in WRS over time. The larger the fundal cap size, the smaller the change in the WRS (p = 0.047, β=−0.35). Conclusions: Cerebrospinal fluid fundal cap size predicts the natural history of hearing in vestibular schwannoma patients. The presence of a smaller fundal cap is correlated with a greater risk of progression of hearing loss and should be a variable considered in the management of small vestibular schwannomas.