Schwannoma Patients Research Articles

Quality of life in patients of unilateral vestibular schwannoma treated with microsurgery: A South-Asian tertiary care Hospital experience

Majority of the published literature on the impact of microsurgery over quality-of-life (QOL) in vestibular schwannoma (VS) patients is retrospective in nature, with variable results, and there has been very little contribution from South-Asia. The authors designed this study to investigate the role of microsurgery in QOL alterations in VS patients, and to compare obtained QOL scores with that of control population. Between February 2017 and March 2018, a prospective/retrospective study was done at our institute. Prospective and retrospective cohorts included, 30 and 34 consecutive patients, respectively, of unilateral VS undergoing microsurgery. QOL assessment was done using Short Form-36 (SF–36), and the Penn Acoustic Neuroma Quality-Of-Life (PANQOL) questionnaires. Prospective cohort underwent QOL assessment at 3 junctures – pre-surgery, 3-months & 1-year post-surgery; while retrospective cohort was assessed only once, at 1-year post-surgery. Age- & sex- matched normal population and diabetic patients were used as controls. In the prospective cohort, patients showed drop in all PANQOL domain/ SF-36 dimension scores at 3-month post-surgery, exception being vitality and general health in SF-36; showed improvement at 1-year follow-up, with majority either levelling or improving their respective pre-surgery scores. Gross total resection, tumors ≤ 3 cm, and age ≤ 45 years had better PANQOL scores at 1-year post-surgery across all the domains. Patients in both the cohorts showed worse QOL compared to normal population, but the gap got narrower at 1-year post-surgery. Our study adds a South-Asian perspective to the pool of prospective knowledge available on QOL following microsurgery in VS patients.

Prevention of cerebrospinal fluid leak after vestibular schwannoma surgery: a case-series focus on mastoid air cells' partition.

Petrous bone pneumatization may be related to cerebrospinal fluid (CSF) leak secondary to vestibular schwannoma surgery. To assess the association between petrous bone pneumatization and CSF leak in vestibular schwannoma surgery. A retrospective study included 222 consecutive vestibular schwannoma patients treated via a retrosigmoid or translabyrinthine approach in a 17-year period in one University Hospital. Association of CSF leak and petrous bone pneumatization, as seen on CT scans, was assessed on ANOVA and Student's t or Chi-squared test in case of non-parametric distribution. One hundred and 75 resections were performed on a retrosigmoid approach and 47 on a translabyrinthine approach. Mean age was 53.6 ± 12.9years. Mean follow-up was 5years 6months. Twenty-six patients (11.7%) showed CSF leak and 8 (3.6%) meningitis. Approach (p = 0.800), gender (p = 0.904), age (p = 0.234), body-mass index (p = 0.462), tumor stage (p = 0.681) and history of schwannoma surgery (p = 0.192) did not increase the risk of CSF leak. This risk was unrelated to mastoid pneumatization (p = 0.266). There was a highly significant correlation between internal acousticus meatus (IAM) posterior wall pneumatization and CSF leak after retrosigmoid surgery (p = 0.008). Eustachian tube packing in the translabyrinthine approach did not decrease risk of CSF leak (p = 0.571). Degree of petrous bone pneumatization was not significantly related to risk of CSF leak, but pneumatization of the posterior IAM wall increased this risk in retrosigmoid surgery. Eustachian tube packing in the translabyrinthine approach is not sufficient to prevent postoperative CSF leak. Both approaches had similar rates of CSF leaks, around 12%.

Optimized preoperative determination of nerve of origin in patients with vestibular schwannoma

In vestibular schwannoma (VS) patients hearing outcome and surgery related risks can vary and depend on the nerve of origin. Preoperative origin differentiation between inferior or superior vestibular nerve may influence the decision on treatment, and the selection of optimal treatment and counselling modalities. A novel scoring system based on functional tests was designed to predict the nerve of origin for VS and was applied to a large number of consecutive patients. A prospective, double blind, cohort study including 93 patients with suspected unilateral VS was conducted at a tertiary referral centre. Preoperatively before tumor resection a functional test battery [video head-impulse test (vHIT) of all semicircular canals (SCC)], air-conducted cervical/ocular vestibular evoked myogenic potential tests (cVEMP, oVEMP), pure-tone audiometry, and speech discrimination was applied. Sensitivity and specificity of prediction of intraoperative finding by a preoperative score based on vHIT gain, cVEMP and oVEMP amplitudes and asymmetry ratios was calculated. For the prediction of inferior vestibular nerve origin, sensitivity was 73% and specificity was 80%. For the prediction of superior vestibular nerve origin, sensitivity was 60% and specificity was 90%. Based on the trade-off between sensitivity and specificity, optimized cut-off values of − 0.32 for cVEMP and − 0.11 for oVEMP asymmetry ratios and vHIT gain thresholds of 0.77 (anterior SCC), 0.84 (lateral SCC) and 0.80 (posterior SCC) were identified by receiver operator characteristic curves. The scoring system based on preoperative functional tests improves prediction of nerve of origin and can be applied in clinical routine.

Facial emotion detection in Vestibular Schwannoma patients with and without facial paresis

ABSTRACT This study investigates whether there exist differences in facial emotion detection accuracy in patients suffering from Vestibular Schwannoma (VS) due to their facial paresis. Forty-four VS patients, half of them with, and half of them without a facial paresis, had to classify pictures of facial expressions as being emotional or non-emotional. The visual information of images was systematically manipulated by adding different levels of visual noise. The study had a mixed design with emotional expression (happy vs. angry) and visual noise level (10% to 80%) as repeated measures and facial paresis (present vs. absent) and degree of facial dysfunction as between subjects’ factors. Emotion detection accuracy declined when visual information declined, an effect that was stronger for anger than for happy expressions. Overall, emotion detection accuracy for happy and angry faces did not differ between VS patients with or without a facial paresis, although exploratory analyses suggest that the ability to recognize emotions in angry facial expressions was slightly more impaired in patients with facial paresis. The findings are discussed in the context of the effects of facial paresis on emotion detection, and the role of facial mimicry, in particular, as an important mechanism for facial emotion processing and understanding.

Case series of vestibular schwannoma patients with no asymmetry in hearing

Objective(1) Describe the presenting symptoms and tumor characteristics of patients who are diagnosed with a vestibular schwannoma (VS) with normal hearing or symmetric hearing loss, and (2) report the prospective growth and treatment of each tumor. MethodsThis is a retrospective cohort study of acoustic neuroma patients who were found to have a VS and normal or symmetric hearing loss at a single tertiary care academic center from 1999 to 2012. Medical records were reviewed collecting the following information: patient demographics, symptoms, MRI characteristics, and treatment modality. Results15/195 (7.7%) patients met criteria for the study. Dizziness was the most common presenting symptom occurring in 9 subjects (60%), followed by headache in 6 (40%), vision changes in 5 (33%), tinnitus in 5 (33%), and unilateral hearing loss in 1 (7%). The average tumor size was 1.07 cm (range 0.3–2.2 cm). Eight (53%) patients presented with intracanalicular tumors. Growth was observed in 6 subjects (40%) with average growth rate in those who exhibited mean growth of 1.8 mm per year. Treatment consisted of surgical removal in 4 cases (27%), gamma knife therapy in 1 (7%), and observation or loss to follow-up in 10 (66%). ConclusionsThe incidence of VS with normal hearing was 7.7% Patients with VSs who do not exhibit unilateral hearing loss present most commonly with dizziness. Most of our patients had small, intracanalicular tumors with the largest tumor measuring 2.2 cm in greatest dimension. Of those who were managed conservatively with repeat imaging and observation, most showed tumor growth.

Head movement kinematics are altered during gaze stability exercises in vestibular schwannoma patients

Gaze stability is the ability of the eyes to fixate a stable point when the head is moving in space. Because gaze stability is impaired in peripheral vestibular loss patients, gaze stabilization exercises are often prescribed to facilitate compensation. However, both the assessment and prescription of these exercises are subjective. Accordingly, here we quantified head motion kinematics in patients with vestibular loss while they performed the standard of care gaze stability exercises, both before and after surgical deafferentation. We also correlate the head kinematic data with standard clinical outcome measures. Using inertial measurement units, we quantified head movements in patients as they transitioned through these two vestibular states characterized by different levels of peripheral damage. Comparison with age-matched healthy control subjects revealed that the same kinematic measurements were significantly abnormal in patients both pre- and post-surgery. Regardless of direction, patients took a longer time to move their heads during the exercises. Interestingly, these changes in kinematics suggest a strategy that existed preoperatively and remained symmetric after surgery although the patients then had complete unilateral vestibular loss. Further, we found that this kinematic assessment was a good predictor of clinical outcomes, and that pre-surgery clinical measures could predict post-surgery head kinematics. Thus, together, our results provide the first experimental evidence that patients show significant changes in head kinematics during gaze stability exercises, even prior to surgery. This suggests that early changes in head kinematic strategy due to significant but incomplete vestibular loss are already maladaptive as compared to controls.

Useful hearing preservation is improved in vestibular schwannoma patients who undergo stereotactic radiosurgery before further hearing deterioration ensues.

The present study evaluates whether hearing deterioration during observation reduces serviceable hearing preservation rates after stereotactic radiosurgery (SRS) in vestibular schwannoma (VS) patients with useful hearing. We retrospectively analyzed 1447 VS patients who underwent SRS between 1992 and 2017. We identified 100 VS patients who had Grade I Gardner- Robertson (GR) hearing at initial diagnosis but were observed without surgery or SRS. We compared hearing after SRS in 67 patients who retained GR Grade I hearing from initial diagnosis to SRS (the hearing maintenance or HM group) to 33 patients whose hearing worsened from GR grade I to grade II (the hearing deterioration or HD group). We also investigated whether a decline in pure tone average (PTA) or speech discrimination score (SDS) before SRS affected hearing preservation after SRS. The serviceable hearing (GR I and II) preservation in HM patients was 80%s, 63%, and 51% at 3, 5, and 10years, respectively. The serviceable hearing preservation in HD patients was 40%, 33%, and 20% at 3, 5, and 10years, respectively. In multivariate analysis, younger age (< 55years, p = 0.045) and HM during observation (p = 0.001) improved serviceable hearing preservation rates. Patients whose PTA increased ≥ 15dB (p = 0.024) or whose SDS declined ≥ 10% (p = 0.019) had reduced serviceable hearing preservation rates. Hearing deterioration during observation before SRS reduced long term hearing preservation rate in VS patients with GR grade I hearing at initial diagnosis. SRS before hearing deterioration was recommended for hearing preservation.

Peritumoral Edema Is Associated With Postoperative Hemorrhage and Reoperation Following Vestibular Schwannoma Surgery.

Background: Postoperative hemorrhage (POH) is a severe complication following vestibular schwannoma surgery that may require surgical treatment. The purpose of our study is to identify risk factors associated with POH and reoperation following the resection of vestibular schwannoma.Methods: We retrospectively recruited 452 vestibular schwannoma patients treated with retrosigmoid approach. The primary outcome was POH, and the secondary outcome was reoperation for POH. Clinical and radiographic data were compared by performing univariate analysis and logistic regression analysis.Results: Among the 452 patients, 37 patients (8.2%) presented with POH and14 patients (3.1%) required reoperation within a 30-day hospitalization period. The univariate analysis showed that peritumoral edema, tumor diameter >30 mm, severe postoperative hypertension, and length of hospital stay were associated with POH and reoperation for POH. Logistic regression analysis showed that peritumoral edema [odds ratio (OR) 4.042, 95% confident interval (CI) 1.830–8.926, P = 0.001] and tumor diameter >30 mm (OR 3.192, 95% CI 1.421–7.168, P = 0.005) were independent predictive factors for POH. Peritumoral edema (OR 7.071, 95% CI 2.342–21.356, P = 0.001) was an independent predictive factor for reoperation by using logistic regression analysis. Further analysis revealed that larger tumor and incomplete tumor resection were both associated with a higher incidence of peritumoral edema.Conclusion: Peritumoral edema and tumor size are independent risk factors for POH following vestibular schwannoma surgery. And larger hematoma occurs more commonly in tumors with peritumoral edema which may require reoperation. Tumor size and extent of tumor resection are associated with peritumoral edema. Close attention should be paid to high-risk patients especially for those who presented with severe postoperative hypertension.

Cochleo-facial corridor to the vestibule and fundus of the internal auditory canal through oval window: a minimal invasive and cochlea sparing approach

This cadaveric work aimed to test the effectiveness of a modified surgical corridor (ExpTSA: expanded transcanal supracochlear approach) developed for anatomic cochlear preservation in selected vestibular schwannoma patients necessitating to perform cochlear implantation for appropriate cases to achieve the best outcome. The ears of 10 cadavers (at mean age 75.70 ± 13.75years, range 45-92years) were dissected from the external auditory canal (EAC) to the internal auditory canal by ExpTSA under the guidance of a microscope and endoscope. All stages of the surgical process were recorded step by step and evaluated morphometrically. The vestibular base was successfully reached in all ears without damaging the cochlear morphology and facial nerve. The vestibular base was 23.33 ± 2.02mm away from the entrance (external orifice) and 10.26 ± 1.33mm from the exit (internal orifice) of EAC. The oval window and vestibular base were measured to be 2.94 ± 1.05mm and 5.87 ± 1.24mm deep from the facial nerve, respectively. The normal areas of the oval window, the exit and entrance of EAC were found as 2.90 ± 0.81 mm2, 42.52 ± 13.66 mm2, and 110.73 ± 25.32 mm2, respectively. After ExpTSA procedure, the areas of the oval window (11.04 ± 2.83 mm2), the exit (122.45 ± 20.41 mm2) and entrance (167.49 ± 30.94 mm2) of EAC were expanded approximately 280%, 188%, and 50%, respectively. The ExpTSA may be performed for accessing to the vestibule and fundus of IAC for tumor removal of intravestibular schwannoma patients (with or without fundus involvement) with unserviceable hearing, preserving the cochlear morphology.

Assessment of Tumor Volume Dynamics and Outcome After Radiosurgery for the Treatment of Vestibular Schwannoma: A Single-Center Experience.

To assess the factors affecting early local and audiometric outcomes in vestibular schwannoma (VS) patients treated with stereotactic radiosurgery (SRS). A retrospective review of medical records. Tertiary referral center. Records of all adult patients who underwent SRS between 2010 and 2016 for the treatment of VS were retrospectively reviewed. Patients treated with microsurgery or multi-fractionation schemes, and those who had neurofibromatosis type 2, were excluded. SRS, tumor volume/size measurements. The impact of tumor volume dynamics on the early local and hearing-related outcomes, together with the factors that influence them following SRS, and comparison of different tumor size measurement methods. From 2010 to 2016, 53 patients underwent single fraction SRS of 12 Gy. Median follow-up time was 32 months (range, 6-79). At the last follow-up, only one patient had clinical progression. Age less than or equal to 65 years (p = 0.04; odds ratio [OR]: 0.17; 95% confidence interval [CI]: 0.03-0.93) and baseline pure-tone average (PTA) level less than or equal to 30 dB (p = 0.03; OR: 0.90; 95% CI: 0.84-0.96) were associated with maintenance of serviceable hearing. On multivariate analysis, PTA remained significant (p = 0.01; OR: 0.04; 95% CI: 0.003-0.45). In patients with a loss of serviceable hearing, the mean volume increase tended to be higher than in the patients whose hearing was maintained. The linear measurement method underestimated, and the A × B × C/2 equation overestimated, the radiological progression compared with 3D-volumetric delineations. During the median observation period of almost 3 years, we reported our early outcome results. Tumor volume increase may have an impact on serviceable hearing loss after SRS. Currently there is no widely accepted method for the evaluation of post-SRS response. Linear measurement and the A × B × C/2 equation produce less reliable estimates of radiological progression compared with 3D-volumetric delineations. Accurate volume measurements with 3D delineations should be considered as part of clinical routine for assessing progression and deciding on salvage therapies.

Vibration-induced nystagmus and head impulse test screening for vestibular schwannoma

Level of evidence II-2 Background Vestibular schwannomas are benign tumors of the eight cranial nerve that may cause asymmetric sensorineural hearing loss (ASHL) and vestibular dysfunction. Objective The aim of this study was to assess the role of the video head impulse test (vHIT) and vibration-induced nystagmus (VIN) test in diagnosing vestibular schwannoma in a population of patients with Asymmetric sensorineural hearing loss. Material and methods For this prospective case-control study, 23 consecutive patients with ASHL and normal magnetic resonance were enrolled in the control group, and 33 consecutive patients with ASHL and vestibular schwannoma were enrolled in the case group. Gold standard was magnetic resonance imaging. Audiometry, vHIT, and VIN tests were performed for each patient. Significance of VIN and vHIT testing was determined by evaluation of their sensitivity, specificity, and correlation with vestibular function tests. Results Regarding the vHIT, sensitivity and specificity were 45.5% and 82.6%, respectively, for horizontal canal gain, 60.6% and 87.6%, respectively, for posterior canal gain, and 45.5% and 78.3%, respectively, when analyzing superior canal gains. Regarding the VIN test, the sensitivity and specificity were 81.8% and 73.9%, respectively, when based on the presence of a VIN with any mastoid stimulation. Conclusions Our results suggest that using the VIN test may be an efficient approach to screen for vestibular schwannoma in patients with asymmetric sensorineural hearing loss. Significance Our results suggest that using the VIN test may be an efficient approach to screen for vestibular schwannoma in patients with ASHL.

Suppression head impulse testing is recommended for vestibular testing of patients with untreated unilateral vestibular schwannoma

Suppression head impulse testing (SHIMP) is a new vestibular method capable of quantifying vestibular function. The aim of this study was to evaluate the feasibility of this test in patients with existing or newly diagnosed vestibular schwannoma (VS) patients by comparing the results with the traditionally used video head impulse test (vHIT or HIMP). Fifty-five patients with unilateral VS underwent a wide battery of audiological and vestibular tests. HIMP results were evaluated using newly introduced objective guidelines based on the trace evaluation of pathological saccades. The sensitivity and specificity of HIMP and SHIMP were evaluated and compared. A new SHIMP parameter is presented; the anticompensatory saccade amplitude ratio (ASAR). We found a marked increase in specificity in HIMP testing using the objective guidelines. SHIMP testing revealed a gain threshold of 0.7 to be optimal in terms of achieving high specificity and sensitivity in relation to HIMP testing. Significant correlations were found between a low ASAR and a high degree of vestibular pathology. The SHIMP test is a viable addition to the standard HIMP test in patients with VS, especially with the addition of the ASAR, which could prove useful in monitoring the residual vestibular function. N/A.

Identification of factors associated with tinnitus outcomes following the microsurgical treatment of vestibular schwannoma patients

Background Tinnitus is common in vestibular schwannoma patients, but the postoperative tinnitus status of these patients and related factors remain unclear. Aims To identify preoperative and operative factors associated with postoperative tinnitus status. Materials and methods Postoperative outcomes were retrospectively assessed in 237 vestibular schwannomas (VS) patients with preoperative tinnitus and 90 VS patients without tinnitus. Results When evaluating patients with preoperative tinnitus, there were significant differences in rates of improvement, no change, and worsening of tinnitus for the translabyrinthine (TL) and retrosigmoid (RS) approaches. Of patients without preoperative tinnitus, there was a significant difference in rates of not developing tinnitus and new-onset tinnitus. Similar results were observed with respect to preoperative hearing. Least-squares analyses revealed that surgical approach and preoperative hearing were independent predictors of postoperative tinnitus. Preoperative pure tone averages for TL group patients that did not develop postoperative tinnitus were 85.8 dB, whereas in patients that developed new-onset tinnitus they were significantly lower (54.9 dB). Conclusions and significance Tinnitus prognosis in VS patients is better following TL microsurgery relative to RS microsurgery and is also better in patients with worse preoperative hearing. New-onset tinnitus was more likely to occur in patients with better preoperative hearing that underwent tumor removal via a TL approach.

Effects of vestibular neurectomy and neural compensation on head movements in patients undergoing vestibular schwannoma resection

The vestibular system is vital for maintaining balance and stabilizing gaze and vestibular damage causes impaired postural and gaze control. Here we examined the effects of vestibular loss and subsequent compensation on head motion kinematics during voluntary behavior. Head movements were measured in vestibular schwannoma patients before, and then 6 weeks and 6 months after surgical tumor removal, requiring sectioning of the involved vestibular nerve (vestibular neurectomy). Head movements were recorded in six dimensions using a small head-mounted sensor while patients performed the Functional Gait Assessment (FGA). Kinematic measures differed between patients (at all three time points) and normal subjects on several challenging FGA tasks, indicating that vestibular damage (caused by the tumor or neurectomy) alters head movements in a manner that is not normalized by central compensation. Kinematics measured at different time points relative to vestibular neurectomy differed substantially between pre-operative and 6-week post-operative states but changed little between 6-week and > 6-month post-operative states, demonstrating that compensation affecting head kinematics is relatively rapid. Our results indicate that quantifying head kinematics during self-generated gait tasks provides valuable information about vestibular damage and compensation, suggesting that early changes in patient head motion strategy may be maladaptive for long-term vestibular compensation.

Predicting Hearing Outcomes in Conservatively Managed Vestibular Schwannoma Patients Utilizing Magnetic Resonance Imaging.

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. Retrospective chart review. Tertiary academic referral center. Three hundred ninety-three adults with a vestibular schwannoma who underwent expectant management with serial audiograms and MRI. Audiogram and MRI. 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. 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). 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.

Can Dizziness Handicap Inventory and Activities-Specific Balance Confidence Scores Assess Vestibular Loss After Vestibular Schwannoma Excision?

Evaluate and compare the Dizziness Handicap Inventory with Activities-specific Balance Confidence scores shortly after vestibular schwannoma excision. Retrospective database review. Tertiary care center. Adults undergoing vestibular schwannoma excision between January 2015 and December 2019. Diagnostic, therapeutic, and rehabilitative. Postoperative change in Dizziness Handicap Inventory scores and Activities-specific Balance Confidence scores 2 to 3 weeks after surgical intervention in relation to preoperative vestibular testing. A total of 49 patients met inclusion criteria. The average change in the Dizziness Handicap Inventory was 6 (p = 0.07, 95% CI 0-13). This was weakly correlated to preoperative caloric testing values (r = -0.31, p = 0.03), but not cervical vestibular evoked myogenic potentials (cVEMP) values (r = -0.17, p = 0.23). The average change in Activities-specific Balance Confidence was -10% (p = 0.007, 95% CI -3 to -17%). This change was moderately correlated with preoperative caloric values (r = 0.42, p = 0.006), but it was not correlated with cVEMP (r = 0.07, p = 0.66). In vestibular schwannoma patients, factors other than preoperative vestibular function likely affect postoperative Dizziness Handicap Inventory and Activities-specific Balance Confidence scores. The change in Activities-specific Balance Confidence was slightly more consistent with expected physiological vestibular loss, and it represents another tool in a multidisciplinary vestibular evaluation of the postoperative patient.

Proton Radiotherapy For Vestibular Schwannomas: A Cohort Study

Radiotherapy for vestibular schwannomas (VS) achieves excellent tumor control rates (90-100%). As long-term survival is excellent in these patients, a paramount focus in therapy is prevention of long-term toxicity. Radiotherapy with proton therapy may improve patient outcomes by reducing radiation dose to surrounding normal tissues. Chart review and volumetric MRI-analyses were performed on vestibular schwannoma patients treated with proton radiotherapy (PT) between 2003-2018 at a single institution. Patients with a minimum radiological follow-up of 12 months were included. Tumor control was defined as not requiring salvage treatment. Available toxicity data were collected. Of 276 identified patients, 221 patients met the inclusion criteria. Tumor control was 96% with a median radiological follow-up of 4.4 years. The majority of patients (62%) received single fraction proton stereotactic radiosurgery (PSRS), and the remaining (38%) received standard fractionated therapy. Fractionated radiated patients had larger median tumor volumes and larger extracanalicular tumor diameters at baseline (p < 0.001). Cystic tumors showed an increased shrinkage rate after treatment, although this did not reach significance (p = 0.084). Facial paresis was seen in 1%, trigeminal neuralgia in 4%, hydrocephalus in 2%, and severe dizziness in 6% of patients receiving proton radiotherapy as primary treatment. Trigeminal neuralgia occurred more often in patients with larger tumor volumes (OR 1.44, p-value 0.005) and in patients that received fractionated therapy (OR 5.0, p = 0.0496). Cochlear mean doses were 8.8 and 43.4 Gy (RBE) for PSRS and fractionated patients, however with wide ranges (0.3 - 12.4 and 1.4 - 53.9 Gy (RBE)). Audiological follow-up was available for 51 patients. Median maximal speech discrimination decreased from 78% to a one-year post-irradiation of 54% to last follow-up (median 48 months) of 33%. Proton radiotherapy for vestibular schwannoma achieves high tumor control and reasonably low toxicity rates. Some sequelae of radiation (vestibular functioning, cognitive functioning, quality of life) warrant further evaluation. Patient subgroups that may significantly benefit from proton therapy should be identified to merit its higher costs as compared to photon therapy.Abstract 3662; TableFractionated treatmentSingle doseSignificanceAge, median, years (range)59 (28 - 85)66 (23 - 86)P < 0.001Tumor volume, median, cc (range)1.04 (0.1 - 10.5)0.6 (0.1 - 4.6)P < 0.001Cystic tumor16 unknown: 1612 unknown: 36P = 0.068Dmean tumor, mean Gy (RBE) (range)52.7 (46.6 - 56.8)13.1 (10.9 - 24.0)-Dmax brainstem, mean Gy (RBE) (range)49.5 (6.5 - 57.9)9.8 (0 - 13.7)-Dmean cochlea, mean Gy (RBE) (range)43.4 (1.4 - 53.9) unknown: 78.8 (0.3 - 12.4) unknown: 50-Facial paresis *20-Trigeminal neuralgia*62OR: 5.089, p = 0.0496Severe dizziness*67-*New onset or increase in symptoms; PT as primary treatment Open table in a new tab

Corrigendum to: "Long-Term Hearing Outcomes Following Stereotactic Radiosurgery in Vestibular Schwannoma Patients-A Retrospective Cohort Study" by Santa Maria et al. Neurosurgery, nyy407, https://doi.org/10.1093/neuros/nyy407.

Corrigendum to: "Long-Term Hearing Outcomes Following Stereotactic Radiosurgery in Vestibular Schwannoma Patients-A Retrospective Cohort Study" by Santa Maria et al. Neurosurgery, nyy407, https://doi.org/10.1093/neuros/nyy407.

Increasing Frailty, Not Increasing Age, Results in Increased Length of Stay Following Vestibular Schwannoma Surgery.

Understand the frailty of vestibular schwannoma surgical patients and how frailty impacts clinical course. Retrospective Cohort. Single-tertiary academic hospital. All patients undergoing vestibular schwannoma surgery. The modified frailty index (mFI) was calculated for all patients undergoing surgery for vestibular schwannoma between 2011 and 2018. Patient demographics and medical history, perioperative course, and postoperative complications were obtained from the medical record. The primary endpoint was hospital length of stay (LOS). Secondary endpoint was postoperative complications. Basic statistical analysis was performed including multivariate linear regressions to determine independent predictors of LOS. There were 218 patients included and the mean age was 48.1 ± 0.9 (range 12-77). One-hundred ten patients were male (50.5%). The mean ICU LOS was 1.6 ± 0.1 days while mean total hospital LOS was 4.3 ± 0.2. There were 145 patients (66.5%) who were robust (nonfrail) with an mFI of 0, while 73 (33.5%) had an mFI of ≥1. Frailty (mFI≥2) was associated with longer hospital LOS compared with the prefrail (p = 0.0014) and robust (p = 0.0004) groups, but was not associated with increased complications (OR = 1.3; 95% CI: 0.5-3.7; p = 0.5925) or ICU LOS (p > 0.05). In multivariate analysis, increased mFI, and NOT increased age, was an independent risk factor for increased hospital LOS (p = 0.027). Increasing frailty, and not increasing age, is an independent risk factor for longer hospital LOS, but not for increased postoperative complications. Patients' frailty status may be useful preoperatively in counselling patients about postoperative expectations and frail vestibular schwannoma patients may require increased health spending costs given their increased hospital LOS.

Outcomes of Gamma Knife Surgery retreatment for growing vestibular schwannoma and review of the literature

ObjectiveGamma Knife surgery has become an accepted treatment for small to medium‑size vestibular schwannoma with a high rate of tumor control and good clinical outcome. When GKS treatment fails to stop tumor growth, GKS retreatment can be proposed in selected cases. This retrospective study examines the clinical and tumor control outcome after the second GKS retreatment for the same vestibular schwannomas. MethodsA total of 14 consecutive vestibular schwannomas patients retreated with 2nd GKS were included: The median time interval between GKS treatments was 44 months, and the median follow‑up duration after last GKS retreatment was 60 months. The median marginal dose used for the first and second treatments was 12 Gy. The median tumor volume at the initial GKS was 2.4cc (range 0.27–3.8) and was 3.8cc (range 1.21–7.6) at the GKS retreatment. ResultsAt the last follow‑up, 93% (13 patients) had tumor growth control, decreased in 4, remained unchanged in 9, and increased tumor size in one patient. New facial or severe trigeminal palsy did not occur after the second GKS retreatment. The hearing was not preserved except in one patient post-GKS retreatment. ConclusionsGKS retreatment after the failure of initial GKS to control vestibular schwannomas growth appears to be an effective strategy and can be proposed as an alternative to microsurgery when the tumor volume remains within the usual radiosurgical range.