Unilateral Sporadic Vestibular Schwannoma Research Articles

A nomogram to predict long-term facial nerve function after vestibular schwannoma resection: a contemporary multi-institutional study

OBJECTIVE The objective of this study was to develop a nomogram to predict long-term facial nerve (FN) function after vestibular schwannoma (VS) resection. METHODS A retrospective cohort study of two tertiary academic skull base referral centers was performed. Consecutive adults > 18 years of age with sporadic unilateral VS who underwent resection between September 2016 and May 2021 were included. FN function in the immediate postoperative period and at the most recent evaluation was measured. RESULTS A total of 306 patients (mean age 49 years, 63% female) were included, with a mean follow-up of 18 months. The mean maximum tumor diameter was 19 mm (range 1–50 mm), and 80 (26.1%) tumors were > 25 mm. Overall, 85% of patients showed good immediate postoperative FN function (House-Brackmann [HB] grade I or II) and 89% maintained good FN function at > 12 months of follow-up. An intraoperative FN electromyographic (EMG) response ≥ 100 µV to 0.05 mA of stimulation (OR 18.6, p < 0.001) was the strongest predictor of good HB grade in the immediate postoperative period. EMG response ≥ 100 µV (OR 5.70, p < 0.001), tumor size ≤ 25 mm (OR 3.09, p < 0.05), and better immediate postoperative HB grade (OR 1.48, p = 0.005) predicted good long-term FN function on multivariable analysis. A point-of-care nomogram based on these data predicted long-term FN function with a sensitivity of 89% and specificity of 69%. CONCLUSIONS Better immediate postoperative HB grade, intraoperative FN EMG response ≥ 100 µV, and tumor size ≤ 25 mm strongly predicted good long-term FN function after VS resection. A point-of-care nomogram based on these variables could serve as a useful tool for postoperative counseling and prognosis of long-term FN recovery.

Comparison of quality of life in vestibular schwannoma patients managed with observation, radiotherapy or microsurgery.

In decision making regarding the management of vestibular schwannomas, alongside clinical outcomes, an understanding of patient reported health-related quality of life measures is key. Therefore, the aim of this research is to compare health-related quality of life in vestibular schwannoma patients treated with active observation, stereotactic radiotherapy and microsurgical excision. A cross-sectional study of patients diagnosed with unilateral sporadic vestibular schwannomas between 1995 and 2015 at a specialist tertiary centre was conducted. Patients completed the Penn Acoustic Neuroma Quality of Life questionnaire and handicap inventories for dizziness, hearing and tinnitus. Of 234 patients, 136 responded (58.1 per cent). Management modality was: 86 observation, 23 stereotactic radiotherapy and 25 microsurgery. Females reported significantly worse dizziness; males reported significantly worse physical disability. Patients less than 65 years old reported significantly worse tinnitus and pain scores. Overall, quality of life was higher in the observation group. Conservative management, where appropriate, is favourable with higher quality-of-life outcomes in this cohort. This must be weighed against the risks of a growing tumour.

An External Validation Study for Automated Segmentation of Vestibular Schwannoma.

To validate how an automated model for vestibular schwannoma (VS) segmentation developed on an external homogeneous dataset performs when applied to internal heterogeneous data. The external dataset comprised 242 patients with previously untreated, sporadic unilateral VS undergoing Gamma Knife radiosurgery, with homogeneous magnetic resonance imaging (MRI) scans. The internal dataset comprised 10 patients from our institution, with heterogeneous MRI scans. An automated VS segmentation model was developed on the external dataset. The model was tested on the internal dataset. Dice score, which measures agreement between ground truth and predicted segmentations. When applied to the internal patient scans, the automated model achieved a mean Dice score of 61% across all 10 images. There were three tumors that were not detected. These tumors were 0.01 ml on average (SD = 0.00 ml). The mean Dice score for the seven tumors that were detected was 87% (SD = 14%). There was one outlier with Dice of 55%-on further review of this scan, it was discovered that hyperintense petrous bone had been included in the tumor segmentation. We show that an automated segmentation model developed using a restrictive set of siloed institutional data can be successfully adapted for data from different imaging systems and patient populations. This is an important step toward the validation of automated VS segmentation. However, there are significant shortcomings that likely reflect limitations of the data used to train the model. Further validation is needed to make automated segmentation for VS generalizable.

Sex Differences in Vestibular Schwannoma.

Vestibular schwannoma (VS) are equally common in men and woman. A number of epidemiological studies have reported on sex-specific aspects of incidence, tumor size, tinnitus and hearing loss. However, data on sex-specific, pre- and post-surgically quality of life (QoL) are rare. The objective of the present study was to determine sex-specific aspects on QoL in VS. Health-related QoL was analyzed in 260 patients (112 male/148 female) with unilateral sporadic VS using general (SF-36: general Short-Form Health Survey), disease-specific (PANQOL: Penn Acoustic Neuroma Quality-of-Life Scale, PANQOL) and symptom-specific (DHI: Dizziness Handicap Inventory; HHI: Hearing Handicap Inventory; THI: Tinnitus Handicap Inventory; FDI: Facial Disability Index) QoL questionnaires. Sex differences were evaluated pre- and postoperative by multi- and univariate analyses based on 200 preoperative and 88 postoperative questionnaires. Female patients were significantly more affected by dizziness, headaches, reduced energy and anxiety. Energy and balance changed similarly in both sexes after surgery. However, postoperative women tended to be more affected by facial palsy and headaches than men. Despite the greater physical impairment, general health improved equivalently or even more in female patients than in males. In conclusion, self-rated QoL in VS is significantly affected by sex and surgery. This should be taken into account when counseling VS patients regarding observation, radiotherapy, and surgery.

Trading mental and physical health in vestibular schwannoma treatment decision.

Observation, radiotherapy and surgery are treatment options in vestibular schwannomas (VS). Decision making differs between centers and is usually based on tumor characteristics (e.g., size) and the expected physical health (PH) outcome (i.e., hearing and facial function). However, mental health (MH) is often under-reported. The objective of the present study was to ascertain the impact of VS treatment on PH and MH. PH and MH were assessed in a prospective cross-sectional study including 226 patients with unilateral sporadic VS before and after surgical removal (SURG). Quality-of-life (QoL) was estimated by self-rating questionnaires: general Short-Form Health Survey (SF-36), Penn Acoustic Neuroma Quality-of-Life Scale (PANQOL), Dizziness Handicap Inventory (DHI), Hearing Handicap Inventory (HHI), Tinnitus Handicap Inventory (THI), and Facial Disability Index (FDI). QoL changes over time as well as predictive factors were accessed by multivariate analyses of covariance (MANCOVA). In total, 173 preoperative and 80 postoperative questionnaires were analyzed. There was a significant PH deterioration related to facial function (FDI, PANQOL-face) after surgery. In line with facial rehabilitation, however, FDI improved within the first five years after surgery and did not differ compared to the preoperative patient cohort, eventually. In contrast, MH (i.e., PANQOL-anxiety) and general health (i.e., PANQOL-GH) improved with surgery and correlated with the extent-of-resection. Physical and mental health is significantly influenced by VS surgery. While PH might decrease after surgery, MH potentially increases when patient is cured. Practitioners should take MH into account before advising an incompletely VS treatment (e.g., subtotal resection, observation or radiosurgery).

Functional Outcome After Simultaneous Vestibular Schwannoma Resection and Cochlear Implantation With Intraoperative Cochlear Nerve Monitoring.

Electrically evoked auditory brainstem response audiometry has emerged as a suitable option to intraoperatively assess cochlear nerve function during vestibular schwannoma resection. This study aimed to analyze the functional outcome and implant usage of patients with preserved auditory nerve responses after simultaneous translabyrinthine schwannoma resection and cochlear implantation. Prospective study. Tertiary referral center. Patients with unilateral sporadic vestibular schwannoma underwent translabyrinthine tumor resection. Intraoperatively, electrically evoked auditory brainstem response audiometry was performed before and after tumor removal. Cochlear implantation was carried out if positive responses were detected after tumor removal indicating cochlear nerve function. Postoperatively, patients were biannually followed-up to assess aided sound field audiometry and word recognition as well as implant usage. Overall, 26 patients with vestibular schwannoma underwent translabyrinthine schwannoma resection. Out of these patients, 15 had positive cochlear nerve responses after tumor removal and concurrently received a cochlear implant. In 13 patients with histologically confirmed vestibular schwannoma, hearing improved by 23.7 ± 33.2 decibels and word recognition by 25.0 ± 42.4% over a mean follow-up period of 18 months. Overall, 12 included patients were regular cochlear implant users. Patients with vestibular schwannoma can benefit substantially from cochlear implantation. Intraoperative assessment of cochlear nerve function using electrically evoked auditory brainstem response audiometry can help to better identify individuals eligible for simultaneous vestibular schwannoma resection and cochlear implantation.

Evidence-based surveillance protocol for vestibular schwannomas: a long-term analysis of tumor growth using conditional probability.

The growth characteristics of vestibular schwannomas (VSs) under surveillance can be studied using a Bayesian method of growth risk stratification by time after surveillance onset, allowing dynamic evaluations of growth risks. There is no consensus on the optimum surveillance strategy in terms of frequency and duration, particularly for long-term growth risks. In this study, the long-term conditional probability of new VS growth was reported for patients after 5 years of demonstrated nongrowth. This allowed modeling of long-term VS growth risks, the creation of an evidence-based surveillance protocol, and the proposal of a cost-benefit analysis decision aid. The authors performed an international multicenter retrospective analysis of prospectively collected databases from five tertiary care referral skull base units. Patients diagnosed with sporadic unilateral VS between 1990 and 2010 who had a minimum of 10 years of surveillance MRI showing VS nongrowth in the first 5 years of follow-up were included in the analysis. Conditional probabilities of growth were calculated according to Bayes' theorem, and nonlinear regression analyses allowed modeling of growth. A cost-benefit analysis was also performed. A total of 354 patients were included in the study. Across the surveillance period from 6 to 10 years postdiagnosis, a total of 12 tumors were seen to grow (3.4%). There was no significant difference in long-term growth risk for intracanalicular versus extracanalicular VSs (p = 0.41). At 6 years, the residual conditional probability of growth from this point onward was seen to be 2.28% (95% CI 0.70%-5.44%); at 7 years, 1.35% (95% CI 0.25%-4.10%); at 8 years, 0.80% (95% CI 0.07%-3.25%); at 9 years, 0.47% (95% CI 0.01%-2.71%); and at 10 years, 0.28% (95% CI 0.00%-2.37%). Modeling determined that the remaining lifetime risk of growth would be less than 1% at 7 years 7 months, less than 0.5% at 8 years 11 months, and less than 0.25% at 10 years 4 months. This multicenter study evaluates the conditional probability of VS growth in patients with long-term VS surveillance (6-10 years). On the basis of these growth risks, the authors posited a surveillance protocol with imaging at 6 months (t = 0.5), annually for 3 years (t = 1.5, 2.5, 3.5), twice at 2-year intervals (t = 5.5, 7.5), and a final scan after 3 years (t = 10.5). This can be used to better inform patients of their risk of growth at particular points along their surveillance timeline, balancing the risk of missing late growth with the costs of repeated imaging. A cost-benefit analysis decision aid was also proposed to allow units to make their own decisions regarding the cessation of surveillance.

Is Cochlear Implantation Effective for Auditory Rehabilitation Following Vestibular Schwannoma Treatment?

Is Cochlear Implantation Effective for Auditory Rehabilitation Following Vestibular Schwannoma Treatment?

Microsurgical treatment of symptomatic vestibular schwannomas in patients under 40: different results before and after age of 30.

In 10-15% of cases of vestibular schwannoma (VS), age at diagnosis is 40years or less. Little is known about the differences in natural history, surgical findings, and postoperative outcomes of such younger patients as compared to those of greater age. To analyze clinical and surgical and imaging data of a consecutive series of n = 50 patients with unilateral sporadic VS, aged 40years or younger - separated in a very young group (15-30years) and a moderately young group (31-40years). Retrospective case series. Fifty consecutive patients under 40years of age underwent microsurgical resection of unilateral sporadic VS via the retrosigmoid approach. The study cohort was subdivided into two groups according to the age range: group A, age range 15-30years (n = 23 patients), and group B, age range 31-40years (n = 27 patients). The adherence of VS capsule to surrounding nervous structures and the tendency of the tumors to bleed were evaluated by reviewing video records; the course of the FN in relation to the tumor's surface was assessed in each case. Microsurgical removal of tumor was classified as total (T), near total (residual tumor volume < 5%), subtotal (residual tumor volume 5-10%), or partial (residual tumor volume > 10%). Mean tumor size of entire cohort was 2.53 (range: 0.6-5.8) cm: 2.84cm in group A and 2.36cm in group B (p = NS). Facial nerve course and position within the cerebellopontine angle did not differ significantly between the two groups. At 6-month follow-up, FN functional outcome was HBI-II in 69.5% in group A, versus 96.3% in group B (p < .001). Hearing preservation was achieved in 60.0% of patients of group A and in 58.3% of group B (p = NS). Total and near-total resection was feasible in 95.6% of cases of group A and in 88.9% of group B (p = NS). Tumor capsule was tightly adherent to nervous structures in 69.6% patients of group A and in 22.2% of group B (p < .05). Significant bleeding was encountered in 56.5% of group A tumors, and in 29.6% of group B tumors (p < .01). Microsurgery of VS in patients aged 40 or less is associated with good functional results, and with high rates of total and near total tumor removal. Patients < 30years of age have more adherent tumor capsules. Furthermore, their tumors exhibit a tendency to larger sizes, to hypervascularization, to profuse intraoperative bleeding and they present worse long-term functional FN results when compared to patients in their fourth decade of life. Our limited experience seems to suggest that a near total resection in very young VS patients with large tumors should be preferred in adherent and hypervascularized cases, in order to maximize resection and preserve function.

Treatment Analysis and Overall Survival Outcomes of Patients With Bilateral Vestibular Schwannoma.

To investigate the clinical presentation, treatment breakdown, and overall survival (OS) outcomes of patients with neurofibromatosis type 2 (NF2)-associated bilateral vestibular schwannoma (NVS). The 2004 to 2016 National Cancer Database was queried for patients with a diagnosis of VS. The "Laterality" code was used to stratify patients into sporadic unilateral vestibular schwannoma (UVS) and NVS. Of the 33,839 patients with VS, 155 (0.46%) were coded for NVS with an average age and tumor size of 37.4 ± 20.5 years and 23.5 ± 18.2 mm. Patients underwent observation (45.3%), surgery (29.3%), and radiotherapy (20.0%), and had a 5.8% 5-year mortality rate. Compared with UVS, NVS was negatively associated with receiving surgery (40.2% versus 29.3%, p = 0.02) while watchful observation was more prevalent (30.1% versus 45.3%, p = 0.001). In NVS, undergoing surgery was associated with larger tumor size (34.5 ± 21.2 versus 17.8 ± 13.3 mm, p = 0.001) and shorter diagnosis-to-treatment time (49.1 ± 60.6 versus 87.0 ± 78.5 d, p = 0.02), radiotherapy was associated with older age (44.4 ± 18.9 versus 35.2 ± 20.6 yr, p = 0.02) and longer diagnosis-to-treatment time (85.9 ± 77.9 versus 53.9 ± 65.5 d, p = 0.04), and observation was associated with smaller tumor size (17.8 ± 15.9 versus 28.0 ± 19.2 mm, p = 0.01). Kaplan-Meier log-rank analysis demonstrated similar 10-year OS between NVS and UVS patients (p = 0.58) without factoring the earlier age of presentation. Furthermore, there were no temporal changes in presentation/management of NVS, and OS was not dependent on the received treatment (p = 0.30). With younger age, larger tumors, and more conservative management, NVS's OS was not treatment-dependent and was similar to sporadic UVS, though the latter should not be interpreted as similar life expectancies due to the much earlier presentation.

Beyond the ABCs: Hearing Loss and Quality of Life in Vestibular Schwannoma

ObjectiveTo assess the impact of differential hearing loss on QOL in sporadic unilateral vestibular schwannoma. Patients and MethodsCross-sectional observational multicenter study including 422 patients with vestibular schwannoma and formal audiometry within 1 year of survey administration, analyzed using multivariable regression. ResultsAmong 422 patients included, the median age was 57 (range, 18-81) years; 223 (53%) were women. Among 390 patients with complete audiometric data, American Academy of Otolaryngology-Head and Neck Surgery class was A in 134 (34%), B in 69 (18%), C in 26 (7%), and D in 161 (41%). A total of 335 of 390 (86%) reported subjective ipsilateral hearing loss (median severity, 6/10 [1 = normal, 10 = deaf]), 166 (43%) reported ipsilateral inability to use the telephone, 155 (37%) reported that hearing loss had affected personal relationships, and 213 (51%) reported difficulty with conversations. After adjusting for age and sex, the odds ratio (OR) for hearing loss adversely affecting relationships was 4.4 for class B hearing vs class A (95% CI, 2.1-9.4; P<.0001). The OR for difficulty with conversations was 2.7 for class B vs class A (95% CI, 1.4-5.3; P=.003). The OR for lost ipsilateral telephone use was 6.3 for class B vs class A (95% CI, 3.2-13.0; P<.0001). Differences between class B and class C were not significant. WRS outperformed PTA as a predictor of hearing-related QOL. The optimal threshold for predicting a significant adverse impact on QOL was WRS less than 72% to 76%. ConclusionHearing loss adversely affects QOL after only modest audiometric disability. The WRS alone appears to be a much more reliable predictor of hearing-related QOL than PTA or American Academy of Otolaryngology-Head and Neck Surgery class.

Simultaneous Vestibular Schwannoma Resection and Cochlear Implantation Using Electrically Evoked Auditory Brainstem Response Audiometry for Decision-making.

The aim of the study was to evaluate the predictive value regarding postoperative hearing benefit of electrically evoked auditory brainstem response audiometry in sporadic vestibular schwannoma patients undergoing simultaneous tumor resection and cochlear implantation. Patients were included in a prospective study conducted between October 2016 and January 2019. The study was conducted at a tertiary care center. Subjects with unilateral sporadic vestibular schwannoma were screened for study participation. Patients underwent translabyrinthine vestibular schwannoma resection and cochlear implantation simultaneously. Electrically evoked brainstem response audiometry was performed during surgery before and after tumor removal using an intracochlear test electrode to objectively evaluate nerve conduction. Electrically evoked brainstem response audiometry results were correlated with postoperative sound field audiometry, word recognition tests, and speech reception thresholds. Quality of life was assessed before and 12 months after translabyrinthine tumor removal and cochlear implantation. Five patients, three male and two female, were included in the study and followed for at least 1 year after implantation. Three of the five patients are daily cochlear implant users with open set speech recognition. Two individuals with negative intraoperative electrically evoked auditory brainstem response results showed no auditory perception with cochlear implant. Simultaneous translabyrinthine vestibular schwannoma resection and cochlear implantation with intraoperative electrically evoked auditory brainstem response measurements is a feasible and promising option for sporadic vestibular schwannoma patients. Preservation of electrically evoked auditory brainstem responses seems to predict good subsequent hearing outcomes.

MRI monitoring of small and medium-sized vestibular schwannomas: predictors of growth

Background: Vestibular schwannomas are among the most common intracranial tumours. Their growth is difficult to predict.Objectives: To study the evolution of small and medium-sized vestibular schwannomas (VSs) and identify factors predictive of growth.Material and methods: This was a retrospective longitudinal study at a tertiary referral centre from January 2011 to January 2018. The inclusion criteria were radiological diagnosis of sporadic unilateral VS of stage I or II. Radiological and clinical data were analysed descriptively and by multivariate logistic regression to identify factors predictive of growth.Results: A total of 1105 cases were discussed in multidisciplinary meetings and 336 patients were included with a mean age of 57.8 years and a mean follow-up time of 24 months. Around two thirds of these patients (62.8%) had non-progressive tumours. Factors identified as predictive of VS growth were the size at diagnosis (OR = 2.622, 95% CI, 1.50–4.66; p = .001) and internal auditory canal filling (OR = 7.672; 95% CI, 4.52–13.43; p < .001).Conclusions and significance: Monitoring is the primary treatment modality for small or medium-sized VSs. As reported here for the first time, internal auditory canal filling is significantly associated with VS growth.

The Conditional Probability of Vestibular Schwannoma Growth at Different Time Points After Initial Stability on an Observational Protocol.

The natural history of vestibular schwannomas (VS) is well documented in the literature, with tumour growth being paramount to decision making for both surveillance and treatment of these patients. Most previous studies refer to the risk of VS growth over a given period of time; however, this is not useful for counselling patients at different stages of their follow-up, as the risk of tumour growth is likely to be less following each subsequent year that a tumour does not grow. Accordingly, we investigated the conditional probability of VS growth at particular time-points, given a patient has not grown thus far. This Bayesian method of risk stratification allows for more tailored and accurate approximations of the risk of growth versus nongrowth of VS. Retrospective analysis of a prospectively collected database in a tertiary referral skull base unit, containing all patients diagnosed between 2005 and 2014 with sporadic unilateral VS and a minimum of 5-year surveillance. A total of 341 patients met the inclusion criteria. The mean age at diagnosis was 67 years, the sizes of the VS at diagnosis were intracanalicular in 49%, small in 39%, medium in 11%, and large in 1%. Over the entire 5-year surveillance period, a total of 139 tumours were seen to grow (41%) and 202 did not grow (59%). At 1 year, the probability of growth given that the tumour had not grown to date was seen to be 21%, at 2 years 12%, at 3 years 9%, at 4 years 3%, and at 5 years 2%. The conditional probability of growth of extracanalicular VS was significantly higher in the first year when compared with intracanalicular VS (29% versus 13%, p = 0.01), but there was no such difference in years 2, 3, 4 or 5 (p = 0.60, 0.69, 0.36, 0.39, respectively). This is the first study in the literature concerned specifically with the conditional probability of VS growth. The data presented here can be used to better inform VS patients of their risk of growth at particular time points in their disease-the longer VS have been observed to be stable, the lower the risk of subsequent growth in a given year. Further, an extracanalicular vestibular schwannoma is more likely to grow in the first year compared with an intracanalicular vestibular schwannoma. Our data also adds support to surveillance protocols with increasingly infrequent MRI scans, as after 4 years of not growing, the risk of growth in year 5 falls to <2%.

Durability of Hearing Preservation Following Microsurgical Resection of Vestibular Schwannoma.

To ascertain long-term hearing outcomes in patients with serviceable hearing following microsurgical resection of sporadic vestibular schwannoma (VS). Retrospective cohort. Tertiary academic referral center. Forty-three adult subjects with unilateral sporadic VS who had serviceable hearing (American Academy of Otolaryngology-Head and Neck Surgery [AAO-HNS] class A or B) on initial postoperative audiogram following microsurgical resection between 2003 and 2016 with a minimum of two postoperative audiograms available for review. Surgical treatment with a retrosigmoid or middle cranial fossa approach. Rate of maintaining serviceable hearing, as estimated using the Kaplan-Meier method, in accordance with the 1995 and 2012 AAO-HNS guidelines on reporting hearing outcomes. The median immediate postoperative pure-tone average (PTA) and word recognition score (WRS) were 31 dB and 95%, respectively. At last follow-up, the median PTA was 38 dB with a median change of 5 dB from initial postoperative audiogram, and the median WRS was 90% with a median change of 0% from initial postoperative audiogram. Eight patients developed non-serviceable hearing at a median of 4.1 years following microsurgical resection (interquartile range, 2.9-7.0). The median duration of hearing follow-up for the 35 patients who maintained serviceable hearing was 3.1 years (interquartile range, 2.2-7.5). Tumor control was achieved in 41 (95%) patients. The rate of maintaining serviceable hearing at 5 years was 81%. Microsurgical resection provides excellent tumor control and durable long-term hearing in those with AAO-HNS class A or B hearing postoperatively. The paradigm of proactive microsurgical resection-when the tumor is small and hearing is good-hinges on the surgeon's ability to preserve residual hearing in a very high percentage of cases at or near preoperative hearing levels to maintain an advantage over conservative observation with regard to long-term hearing preservation.

Cochlear Dead Regions in Sporadic Unilateral Vestibular Schwannomas Using the Threshold-Equalizing Noise Test

Background: Vestibular schwannoma (VS) is a benign intracranial neoplasm originating in the Schwann cells of the vestibular nerve. Despite its origin, the most common symptom is sensorineural hearing loss which is presented in more than 90% of patients. The underlying pathophysiology of this hearing loss has not been fully understood. Objective: To assess the in vivo function of cochlear inner hair cells and spiral ganglion neurons in VS, cochlear dead regions (DRs) were evaluated via the threshold-equalizing noise (TEN) test in untreated VS patients. Method: Untreated patients diagnosed with sporadic unilateral VS and normal contralesional hearing were enrolled from July 2011 to June 2016. Audiometric evaluation including TEN tests were performed. Based on the magnetic resonance findings, characteristics of individual tumors were assessed. Results: The average pure-tone threshold (word recognition score [WRS]) of 23 enrolled patients was 42.7 dB (76.1%). Nineteen DRs (11.8% of 161 tested frequencies) were found in 8 patients (34.8% of enrolled cases). Among the intracanalicular (IAC) tumors, 6 out of 10 ears (60%) carried DRs, while 2 of 13 (15.4%) showed DRs among the cerebellopontine angle (CPA) lesions (p = 0.039). Pure-tone thresholds and WRS were not different between the two groups. Logistic regression analysis showed that the tumor location, IAC versus CPA, was significantly associated with DRs (p = 0.041, Nagelkerke R² = 0.471), whereas age, sex, tumor size, distance from the tumor to the cochlea, T2-weighted hypointensity on the MRI and pure-tone thresholds showed no significance. Conclusions: Cochlear DRs are detected in hearing losses associated with unilateral sporadic VS using the TEN test. Individual DRs were detected variously in high, mid, or low frequencies. In our preliminary data, IAC tumors showed a higher number of DRs than CPA tumors despite similar average hearing thresholds. Further studies including longitudinal follow-up of hearing as well as change in DRs may provide useful information about VS patients.

Decision Making in the Wait-and-Scan Approach for Vestibular Schwannomas: Is There a Price to Pay in Terms of Hearing, Facial Nerve, and Overall Outcomes?

The wait-and-scan modality has emerged as an important strategy in the management of vestibular schwannoma (VS) as it has been demonstrated that many tumors grow slowly or do not show any growth over long periods. To analyze long-term outcomes of wait-and-scan in the treatment of patients with VS, discuss the factors contributing to the decision making, determine the inherent risks of the policy, and compare our results with literature. In total, 576 patients with sporadic unilateral VS who were managed with wait-and-scan were reviewed retrospectively. Of these, a subset of 154 patients with 5-yr follow-up was separately analyzed. The tumor characteristics including patterns of growth, rate of growth, hearing outcomes, and likely factors affecting the above parameters were analyzed. The mean period of follow-up was 36.9 ± 30.2 mo. The mean age was 59.2 ± 11.6 yr. Thirteen different patterns of tumor growth were observed. Eighty-four (54.5%) of 154 tumors with 5-yr follow-up showed no growth throughout 5 yr. Fifty-six (36.4%) tumors showed mixed growth rates. Only 57 (37%) patients had serviceable hearing at the start of follow-up, but 32 (56.1%) maintained it at the end of follow-up. One hundred fifty (26%) of the 576 patients who failed wait-and-scan had to be taken up for surgery. While there may be no price to pay in wait-and-scan as far as hearing is concerned, this may not be the case for facial nerve outcomes, wherein the results may be better if the patients are taken earlier for surgery.

Immediate and Long-term Hearing Outcomes With the Middle Cranial Fossa Approach for Vestibular Schwannoma Resection.

To analyze the immediate postoperative and long-term hearing outcome data in patients who have undergone hearing preservation attempts with the middle cranial fossa (MCF) approach for the resection of sporadic vestibular schwannoma. Retrospective review of a surgical patient cohort. Tertiary academic referral center. Adult patients with unilateral sporadic vestibular schwannoma. Surgical treatment with a MCF approach. Comparison of pre- and postoperative audiometric data in accordance with the 1995 and 2012 American Academy of Otolaryngology/Head and Neck Surgery guidelines on reporting hearing outcomes and with a word recognition score only scale. Long-term hearing outcome data were analyzed in the following postoperative groups: 3 to 5, 6 to 8, 9 to 11, and 12+ years after surgery. From 1999 to 2016, 174 patients underwent the MCF approach and 155 of them met inclusion criteria for analysis of hearing outcome data. Class A or B hearing was preserved in 70% of the entire cohort after recovery. Seventy-one patients with measurable hearing met criteria for long-term data analysis. The rate of American Academy of Otolaryngology/Head and Neck Surgery class A or B hearing preservation was 82% at 3 to 5 years and declined thereafter. The rate of word recognition score class I or II hearing preservation was 98% at 3 to 5 years and declined less rapidly thereafter. Patients with preoperative Class A hearing had significantly higher rates of successful hearing preservation at all postoperative intervals. Delayed hearing loss occurs in a progressively increasing fashion but speech understanding remains durable for a majority of patients whose hearing is initially preserved with the MCF approach.

Predictors of Preoperative Tinnitus in Unilateral Sporadic Vestibular Schwannoma.

Nearly two-thirds of patients with vestibular schwannoma (VS) are reporting a significantly impaired quality of life due to tinnitus. VS-associated tinnitus is attributed to an anatomical and physiological damage of the hearing nerve by displacing growth of the tumor. In contrast, the current pathophysiological concept of non-VS tinnitus hypothesizes a maladaptive neuroplasticity of the central nervous system to a (hidden) hearing impairment resulting in a subjective misperception. However, it is unclear whether this concept fits to VS-associated tinnitus. This study aims to determine the clinical predictors of VS-associated tinnitus to ascertain the compatibility of both pathophysiological concepts. This retrospective study includes a group of 478 neurosurgical patients with unilateral sporadic VS evaluated preoperatively regarding the occurrence of ipsilateral tinnitus depending on different clinical factors, i.e., age, gender, tumor side, tumor size (T1-T4 according to the Hannover classification), and hearing impairment (Gardner-Robertson classification, GR1-5), using a binary logistic regression. 61.8% of patients complain about a preoperative tinnitus. The binary logistic regression analysis identified male gender [OR 1.90 (1.25-2.75); p = 0.002] and hearing impairment GR3 [OR 1.90 (1.08-3.35); p = 0.026] and GR4 [OR 8.21 (2.29-29.50); p = 0.001] as positive predictors. In contrast, patients with large T4 tumors [OR 0.33 (0.13-0.86); p = 0.024] and complete hearing loss GR5 [OR 0.36 (0.15-0.84); p = 0.017] were less likely to develop a tinnitus. Yet, 60% of the patients with good clinical hearing (GR1) and 25% of patients with complete hearing loss (GR5) suffered from tinnitus. These data are good accordance with literature about non-VS tinnitus indicating hearing impairment as main risk factor. In contrast, complete hearing loss appears a negative predictor for tinnitus. For the first time, these findings indicate a non-linear relationship between hearing impairment and tinnitus in unilateral sporadic VS. Our results suggest a similar pathophysiology in VS-associated and non-VS tinnitus.

Fractionated stereotactic radiation therapy for vestibular schwannomas: Dosimetric factors predictive of hearing outcomes

PurposeTo determine dosimetric factors predictive of hearing loss in vestibular schwannoma (VS) patients treated with definitive fractionated stereotactic radiation therapy (FSRT), and to report tumor control, serviceable hearing preservation, and cranial nerve toxicities. Methods and materialsWe identified 45 patients (29 men and 16 women) with unilateral sporadic VS, who underwent definitive FSRT. All patients had serviceable hearing prior to treatment, defined as Gardner-Robertson Class 1 or 2. All patients underwent an audiogram before the start of treatment and serial audiometric assessments after treatment. The median audiometric follow-up time was 35.2 months (range, 5.0-89.7 months). Patients underwent a median of 4.5 (range, 1-9) posttreatment audiograms. The ipsilateral cochlea was contoured retrospectively, and dosimetric data were used to determine factors predictive of losing serviceable hearing. The median clinical follow-up time was 29.9 months (range, 1.5-83.6 months). ResultsAt the time of the last audiometric follow-up, 62% of patients retained serviceable hearing. The actuarial 1-, 2-, and 3-year serviceable hearing preservation rates were 83%, 75%, and 51%, respectively. The estimated median time to loss of serviceable hearing was 42.2 months. On multivariate analysis, cochlear volume <0.15 mL (hazard ratio, 2.849; 95% confidence interval, 1.116-7.270; P = .029) and mean cochlear dose <4000 cGy (hazard ratio, 3.178; 95% confidence interval, 1.116-9.049; P = .030) were statistically significant variables associated with serviceable hearing preservation. The actuarial tumor control was 100%. Three of 39 patients (8%) developed hemifacial spasm after FSRT (House-Brackmann Grade 3), 2 of which completely resolved. No patients experienced deterioration in trigeminal nerve function after FSRT. ConclusionsFractionated stereotactic radiation therapy can provide excellent tumor control with acceptable clinical outcomes. The mean dose to the cochlea is highly predictive of the probability of maintaining serviceable hearing after FSRT.