Vestibular Schwannoma Patients Research Articles

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.

Long-term prognosis of preserved useful hearing after surgery in patients with vestibular schwannoma: a study of 91 cases.

In patients with a vestibular schwannoma, some studies have reported that useful hearing preserved initially after surgery deteriorates gradually in the long term. Studies with more patients are needed to clarify the maintenance rate of postoperative hearing function and to identify prognostic of hearing function. Ninety-one patients (mean age, 39.5 years; mean tumor size, 18.9 mm) with preserved useful hearing immediately after surgery were retrospectively analyzed. The useful hearing was defined as the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) classes A and B. Hearing tests, including auditory brainstem responses (ABR) and distortion product otoacoustic emissions (DPOAE), were evaluated preoperatively, immediately after surgery, and at outpatient follow-up. At the final follow-up (mean, 63.0 months), the useful hearing was maintained in 79 patients (87%), and the hearing class remained unchanged during the follow-up period in 40 patients (44%). Significant predictors of useful hearing maintenance were AAO-HNS class A immediately after surgery, improvement of ABR, and the absence of postoperative DPOAE deterioration. Postoperative DPOAE deterioration correlated with hearing class deterioration. Despite hearing being preserved in vestibular schwannoma patients immediately after surgery, Thirteen percent lost their useful hearing during the long follow-up period, and hearing class worsened in 55% of the patients. This study, which analyzed one of the largest series of vestibular schwannoma patients, demonstrated that retrocochlear condition is a key factor for useful hearing maintenance. In patients with vestibular schwannoma who have preserved hearing function, regular postoperative monitoring of hearing function is as important as regular MRI.

Progression of Contralateral Hearing Loss in Patients With Sporadic Vestibular Schwannoma.

Background and Introduction: Vestibular schwannomas (VSs) are the most common tumors of the cerebellopontine angle, typically presenting unilaterally with ipsilateral sensorineural hearing loss (SNHL). The mechanism of tumor-induced hearing loss has recently been shown to be related to secreted tumor factors, in addition to mechanical compression of the adjacent auditory nerve, and these factors may percolate through CSF or blood to affect contralateral hearing as well.Methods: This is a retrospective study of medical records for patients treated for VS at Mass Eye and Ear from January 1994 through October 2018. Included patients had unilateral VS and sequential audiometry allowing for longitudinal assessment of hearing over time. Mass Eye and Ear's audiology database was used to select age- and sex-matched case controls, also with sequential audiometry, from the non-VS population. Subgroup analysis was performed by age, sex, baseline hearing, and tumor size at initial diagnosis. Hearing loss progression was performed using Kaplan-Meier analysis to account for variable follow-up times.Results: A total of 661 patients were identified with VS and sequential audiometry. The population was predominantly female vs. male (368 vs. 293, p = 0.0035), driven primarily by younger patients with Koos 4 tumors (76 female vs. 49 male, p = 0.016). Patients with normal baseline hearing bilaterally (N = 241) demonstrated no significant difference in hearing loss progression in VS-contralateral vs. control ears. Patients with abnormal baseline VS-ipsilateral hearing (N = 190), however, demonstrated significantly higher likelihood of reaching moderate SNHL in VS-contralateral ears. Subgroup analysis by age, sex, and baseline tumor size did not yield any subgroup-specific trends for hearing loss progression.Discussion and Conclusion: This is the largest study to date tracking long-term bilateral hearing outcomes in patients with VS, and demonstrates that, in patients with abnormal hearing in the VS-ipsilateral ear, there exists a long-term risk of progression to moderate hearing loss in the contralateral ear as well. Combined with the absence of significant changes in word understanding in the affected ears, these findings may provide clues to the nature of tumor-secreted factors involved in VS-associated hearing loss. Female predominance within the VS patient population is confirmed, driven mostly by younger female patients with Koos 4 tumors.

MMP-14 (MT1-MMP) Is a Biomarker of Surgical Outcome and a Potential Mediator of Hearing Loss in Patients With Vestibular Schwannomas

Improved biomarkers are needed for vestibular schwannoma (VS), the most common tumor of the cerebellopontine angle, as existing clinical biomarkers have poor predictive value. Factors such as tumor size or growth rate do not shed light on the pathophysiology of associated sensorineural hearing loss (SNHL) and suffer from low specificity and sensitivity, whereas histological markers only sample a fraction of the tumor and are difficult to ascertain before tumor treatment or surgical intervention. Proteases play diverse and critical roles in tumorigenesis and could be leveraged as a new class of VS biomarkers. Using a combination of in silico, in vitro, and ex vivo approaches, we identified matrixmetalloprotease 14 (MMP-14; also known as MT1-MMP), from a panel of candidate proteases that were differentially expressed through the largest meta-analysis of human VS transcriptomes. The abundance and proteolytic activity of MMP-14 in the plasma and tumor secretions from VS patients correlated with clinical parameters and the degree of SNHL. Further, MMP-14 plasma levels correlated with surgical outcomes such as the extent of resection. Finally, the application of MMP-14 at physiologic concentrations to cochlear explant cultures led to damage to spiral ganglion neuronal fibers and synapses, thereby providing mechanistic insight into VS-associated SNHL. Taken together, MMP-14 represents a novel molecular biomarker that merits further validation in both diagnostic and prognostic applications for VS.

Management and Outcomes of Sporadic Vestibular Schwannoma: A Longitudinal Study Over 12 Years.

To evaluate the management of sporadic vestibular schwannomas (VS) with a 12-year follow-up. Retrospective study of all VS patients initially treated in 2005 in a tertiary referent center. Initial decision making for microsurgical resection (MSR) or wait-and-scan (WaS) was according to VS size and hearing; subsequently, MSR or stereotactic radiosurgery (SRS) was proposed dependent on VS growth and size, hearing, and patient's age or willingness. Two hundred and one sporadic VS were included. The first management apportionment was 120 WaS (61.5%), 72 MSR (37%), three SRS (1.5%), and six others refused MSR and were lost to follow-up (LFU). Within 1 year, 95 (47%) VS were surgically removed; 17 (8.5%) were treated by SRS; and 35 (17.5%) were LFU. The proportions for SRS and LFU were virtually unchanged for the following years, and the proportion under MSR increased slightly within 3 years and then remained stable. Finally, at 12 years, 104 (51.5%) cases had been operated on, 21 (10.5%) treated by SRS, 23 (11.5%) still under WaS, and 53 (26.5%) LFU, which were mainly intracanalicular. The initially and subsequently operated cases presented similar hearing preservation rates and good facial nerve function outcomes. This longitudinal study of a large number of VS, which were diagnosed over a short period of time and followed for 12 years, provides new information on both the natural history of these benign tumors and individual patient concerns. This study recommends use of the WaS policy for small and mid-sized VS before active therapeutic decision making. 3 Laryngoscope, 131:E970-E976, 2021.

MRI based volumetric measurements of vestibular schwannomas in patients with neurofibromatosis type 2: comparison of three different software tools

Neurofibromatosis type 2 is a neurogenetic disorder with an incidence of about 1:33.000. Hallmarks are bilateral benign vestibular schwannomas, which can lead to deafness or brainstem compression. Volumetric tumor measurements are essential to assess the efficacy of new therapies. We present a statistical and methodical comparison of three volumetric image analysis tools. We performed volumetric measurements on phantoms with predefined volumes (0.1 to 8.0 ml) and tumors seen on 32 head MRI scans from eight NF2 patients with BrainLab, ITK-Snap, or OsiriX. The software was compared with regard to accuracy and reproducibility of the measurements and time required for analysis. The mean volume estimated by all three software programs differed significantly from the true volume of the phantoms, but OsiriX and BrainLab gave estimates that were not significantly different from each other. For the actual tumors, the estimated volumes with all three software tools showed a low coefficient of variability, but the mean volume estimates differed among the tools. OsiriX showed the shortest analysis time. Volumetric assessment of MRI images is associated to an intrinsic risk of miscalculation. For precise volumes it is mandatory to use the same volumetric tools for all measurements.

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.

What Clinicians Should Consider to Determine a More Beneficial Treatment Strategy for Small to Medium Sized Vestibular Schwannoma With Serviceable Hearing: A Single Surgeon's Long-term Outcome of Microsurgery and Gamma Knife Radiosurgery.

The number of small to medium sized vestibular schwannoma (VS) patients presenting with serviceable hearing has steadily increased. There are various treatment strategies for small to medium sized VS, including microsurgery (MS), gamma knife radiosurgery (GKS), and serial observations using magnetic resonance imaging. In this study, we presented the long-term outcomes of patients with small to medium sized VS with serviceable hearing. We also evaluated the potential prognostic factors for hearing preservation and discussed appropriate treatment strategies. A retrospective review of 504 cases of all VS patients who underwent MS or GKS between 1993 and July 2019 was conducted. Surgical resection was performed on 267 patients using the retro-sigmoid approach and 55 (20.6%) of them were small to medium sized VS. GKS was performed on 237 patients and 175 (73.8%) of them were small to medium sized VS. Small to medium sized VS was defined as less than 25 mm in the greatest dimension. After applying the inclusion and exclusion criteria, 51 patients with small to medium sized VS with serviceable hearing were enrolled in this study and underwent either MS (n = 21) or GKS (n = 30). To define the clinical characteristics of the patients, clinical data at the time of treatment, age, sex, presenting symptoms, tumor location type, preoperative hearing status, posttreatment related complications, recurrence, and hearing loss progression-free survival data were collected. In the MS group, the hearing preservation rate was 71.4% and the tumor control rate was 100%. In the GKS group, the tumor control rate was 93.3% and two patients experienced recurrence at a median interval of 41.5 months. Kaplan-Meier curves showed that the hearing progression-free survival rates at 1-, 3-, and 5-years following GKS were 80, 66.7, and 53.3%, respectively. The MS group had a higher hearing preservation rate at 5 years (71.4 versus 53.3%), but the difference did not reach statistical significance (p = 0.173). Hearing preservation was statistically significant when the preoperative hearing status was class A in the GKS group (p = 0.016), but it was not statistically significant in the MS group (p = 0.777). In the MS group, medial type VS had a higher hearing preservation rate (80%) than the lateral fundal extended type VS (63.6%), and this difference was almost close to statistical significance (p = 0.058). The GKS group had a higher occurrence of postoperative tinnitus (23.3%) than the MS group (9.5%). MS was more suitable for patients who are younger, have good physical status, good preoperative hearing status including AAO-HNS class B, and medial type VS. GKS was more suitable for patients who are elderly, have poor physical status, preoperative AAO-HNS class A hearing.

Ipsilateral Cochlear Implantation in the Presence of Observed and Irradiated Vestibular Schwannomas.

Historically, eventual loss of cochlear nerve function has limited patients with neurofibromatosis type 2 (NF2) to auditory brainstem implants (ABI), which in general are less effective than modern cochlear implants (CI). Our objective is to evaluate hearing outcomes following ipsilateral cochlear implantation in patients with NF2 and irradiated vestibular schwannomas (VS), and sporadic VS that have been irradiated or observed. Multi-center retrospective analysis of ipsilateral cochlear implantation in the presence of observed and irradiated VS. MESH search in NCBI PubMed database between 1992 and 2019 for reported cases of cochlear implantation with unresected vestibular schwannoma. Seven patients underwent ipsilateral cochlear implantation in the presence of observed or irradiated vestibular schwannomas. Four patients had sporadic tumors with severe-profound contralateral hearing loss caused by presbycusis/hereditary sensorineural hearing loss, and three patients with NF2 lost contralateral hearing after prior surgical resection. Prior to implantation, one VS was observed without growth for a period of 7 years and the others were treated with radiotherapy. Mean post-operative sentence score was 63.9% (range 48-91) at an average of 28 (range 2-84) months follow up. All patients in this cohort obtained open set speech perception. While analysis of the literature is limited by heterogenous data reporting, 85% of implants with observed schwannomas achieved some open set perception, and 67% of patients previously radiated schwannomas. Furthermore, blending literature outcomes for post implantation sentence testing in quiet without lip-reading show 59.0 ± 35% for patients with CI and observed tumors and 55.7 ± 35% for patients with radiated tumors, with both groups ranging 0 to 100%. This retrospective series and literature review highlight that hearing outcomes with CI for VS patients are superior to those achieved with ABI. However, important considerations including imaging, delayed hearing loss, and observation time cannot be ignored in this population.

Comparison of translabyrinthine and retrosigmoid approach for treating vestibular schwannoma: A meta-analysis

BackgroundTo date, the literature directly comparing the translabyrinthine approach and retrosigmoid approach in the operation of patients with vestibular schwannoma was limited. We aimed to evaluate postoperative complications between translabyrinthine approach and retrosigmoid approach for treating vestibular schwannoma patients. Material and MethodPotential publications were selected from PubMed, Web of Science and Cochrane Library. Gray relevant studies were manually searched. We set the searching time spanning from the creation date of electronic engines to February 2020. STATA version 12.0 was exerted to process the pooled data. ResultsA total of 9 literature included in the study, involving 2429 patients, hails from the Germany, USA, Canada, Italy, and France. Of these 2429 patients with vestibular schwannoma, there were 1628 cases from the translabyrinthine approach group versus 801 cases from the retrosigmoid approach group. The results demonstrated that the translabyrinthine approach group was associated with a lower rate of tinnitus (OR = 2.687; 95 %CI, 1.167−6.191; P = 0.02) and cranial nerve deficit (OR = 2.946; 95 %CI, 1.562−5.557; P = 0.001). And the translabyrinthine approach group was associated with a higher total resection rate (OR = 0.246; 95 %CI (0.071−0.848); P = 0.026). However, no statistic differences were found in the incidence of the near total (OR = 0.751; P = 0.351), subtotal resection (OR = 3.664; P = 0.109), postoperative facial nerve dysfunctions (OR, 0.763; P = 0.626), postoperative meningitis (OR = 2.7; P = 0.279), cerebrospinal fluid leak (OR = 1.225; P = 0.777), postoperative headache (OR = 1.412; P = 0.339), ophthalmic complications (OR = 0.87; P = 0.59), and vascular complications (OR = 2.501; P = 0.139). ConclusionBased on current evidence, the translabyrinthine approach was associated with a higher rate of total resection and a lower rate of the tinnitus and cranial nerve deficit. But the risk of cranial nerve deficit was clearly affected by the preoperative status. And a translabyrintine approach could imply a complete sensorineural hearing loss, which contribute to the lower rate of postoperative tinnitus. Consequently, more evidence-based researches are needed to supplement this opinion.

Interchangeability of three different methods of calculating Pure Tone Average in patients with vestibular schwannoma to assess the risk of surgery-related hearing loss.

<b>Background:</b> Patients with vestibular schwannoma (VS) most commonly present with hearing threshold reduction for high frequencies and a falling type of audiometric curve. However, it is doubtful whether all Pure Tone Averages described in the literature characterize patients with VS correctly, as the type of PTA which comprises higher frequencies may be more appropriate for hearing status assessment in those patients. <br><b>Aim:</b> The aim of this study was to analyze 3 common methods of calculating Pure Tone Averages (PTA1 - 500, 1000, 2000 and 3000 Hz; PTA2 - 500, 1000, 2000 and 4000 Hz; PTA3 - 500, 1000 and 2000 Hz) and to determine which of them is the most reliable for the assessment of VS patients. <br><b>Material and Methods:</b> The study group included 86 patients operated on due to vestibular schwannoma accessed via the middle cranial fossa. <br><b>Results:</b> Regarding the method of calculating Pure Tone Averages (PTA1, PTA2 and PTA3) identical or similar correlations were found between the preoperative values of Pure Tone Averages (PTA1, PTA2 and PTA3) and surgery-related hearing loss, as well as individual parameters of audiologic tests. <br><b>Conclusions:</b> Pure Tone Averages calculated according to 3 different methods (PTA1, PTA2, PTA3) may be used interchangeably in the assessment of hearing in VS patients.

Lateralization of facial emotion processing and facial paresis in Vestibular Schwannoma patients.

ObjectiveThis study investigates whether there exist differences in lateralization of facial emotion processing in patients suffering from Vestibular Schwannoma (VS) based on the presence of a facial paresis and their degree of facial functioning as measured by the House Brackmann Grading scale (HBG).MethodsForty‐four VS patients, half of them with a facial paresis and half of them without a facial paresis, rated how emotive they considered images of faces showing emotion in the left versus right visual field. Stimuli consisted of faces with a neutral half and an emotional (happy or angry) half. The study had a mixed design with emotional expression (happy vs. angry) and emotional half (left vs. right visual field) of the faces as repeated measures, and facial paresis (present vs. absent) and HBG as between subjects’ factors. The visual field bias was the main dependent variable.ResultsIn line with typical findings in the normal population, a left visual field bias showed in the current sample: patients judged emotional expressions shown in the left visual field as more emotive than those shown in the right visual field. No differences in visual field bias showed based on the presence of a facial paresis nor based on patients’ HBG.ConclusionVS patients show a left visual field bias when processing facial emotion. No differences in lateralization showed based on the presence of a facial paresis or on patients’ HBG. Based on this study, facial paresis thus does not affect the lateralization of facial emotion processing in patients with VS.

Machine learning approach for prediction of hearing preservation in vestibular schwannoma surgery

In vestibular schwannoma patients with functional hearing status, surgical resection while preserving the hearing is feasible. Hearing levels, tumor size, and location of the tumor have been known to be candidates of predictors. We used a machine learning approach to predict hearing outcomes in vestibular schwannoma patients who underwent hearing preservation surgery: middle cranial fossa, or retrosigmoid approach. After reviewing the medical records of 52 patients with a pathologically confirmed vestibular schwannoma, we included 50 patient’s records in the study. Hearing preservation was regarded as positive if the postoperative hearing was within serviceable hearing (50/50 rule). The categorical variable included the surgical approach, and the continuous variable covered audiometric and vestibular function tests, and the largest diameter of the tumor. Four different algorithms were lined up for comparison of accuracy: support vector machine(SVM), gradient boosting machine(GBM), deep neural network(DNN), and diffuse random forest(DRF). The average accuracy of predicting hearing preservation ranged from 62% (SVM) to 90% (DNN). The current study is the first to incorporate machine learning methodology into a prediction of successful hearing preservation surgery. Although a larger population may be needed for better generalization, this study could aid the surgeon’s decision to perform a hearing preservation approach for vestibular schwannoma surgery.

Quality of life, social function, emotion, and facial paresis in Dutch vestibular schwannoma patients.

Objective(s)The present study aimed to replicate the finding that vestibular schwannoma (VS) patients with facial paresis experience lower health related quality of life (QoL) than those without facial paresis in a Dutch sample, and to extend these findings by measuring VS patients' overall satisfaction with life, social function, and emotion.MethodsForty‐seven VS patients, differing in degree of facial functioning, half of them with and half of them without a facial paresis, answered questionnaires about health related QoL (SF‐36 and PANQOL), overall satisfaction with life, fear of being evaluated negatively by others, social avoidance and distress, and characteristics and symptoms of depression.ResultsWe observed that VS patients with facial paresis experience lower health‐related QoL as well negatively impacted social function and emotion compared to VS patients without facial paresis. VS patients with facial paresis experienced lower overall satisfaction with life, more characteristic symptoms of depression, and more fear of being evaluated negatively by others than VS patients without facial paresis.ConclusionThese findings corroborate previous research showing an association between impaired facial functioning and lower QoL, but also extend them by showing differences on the quality of social function and emotion. Being aware of this difference between VS patients with and without facial paresis informs health practitioners regarding the specific support these patients might need. Moreover, it is also relevant to consider the influence of a facial paresis on patients' life when deciding between treatment options and in case of surgery the type of resection.Level of evidence3

The prevalence and clinical characteristics of vestibular schwannoma among patients treated as sudden sensorineural hearing loss: A 10-year retrospective study in southern China.

To review the prevalence and clinical characteristics of vestibular schwannoma (VS) in patients with sudden sensorineural hearing loss (SSNHL) in southern China. This study examined the medical records and MRI findings of all the 1249 patients diagnosed with SSNHL between May 2009 and April 2019 in the Division of Otolaryngology at Peking University Shenzhen Hospital. Among the 1249 patients with SSNHL, VS was found in 14 (1.12%). Among 14 patients, 11 (78.6%) complained of tinnitus and 3 patients (21.4%) complained of dizziness as accompanying symptoms. There was one patient with SSNHL in right ear who had an incidental finding of VS in the contralateral ear. 2 patients (14.3%) had normal auditory brainstem response (ABR) test and 3 patients (21.4%) had hearing recovery. The size of tumors ranged from 6.1mm to 24.2mm, with 7 grade 1 tumors, 4 grade 2 tumors, and 3 grade 3 tumors. The total MRI screening cost was $130,857 and the average MRI cost for identifying a VS patient was $9346. The prevalence of VS among patients treated as SSNHL was 1.12%. Predicting the risk of VS in SSNHL by the audiogram patterns, pure tone audiometry or hearing recovery is not relivable. Compared with ABR, MRI is more suitable for the assessment of VS in patients with SSNHL in China.

Postoperative Hearing Preservation in Patients Undergoing Retrosigmoid Craniotomy for Resection of Vestibular Schwannomas: A Systematic Review of 2034 Patients.

Vestibular schwannomas (VS) are benign tumors derived from Schwann cells ensheathing the vestibulocochlear nerve. The retrosigmoid (RS) surgical approach is useful to resect tumors of multiple sizes while affording the possibility of preserving postoperative hearing. To conduct a systematic review of published literature investigating hearing preservation rates in patients who underwent the RS approach for VS treatment. The PubMed, Scopus, and Embase databases were surveyed for studies that reported preoperative and postoperative hearing grades on VS patients who underwent RS treatment. Hearing preservation rates were calculated, and additional patient demographic data were extracted. Tumor size data were stratified to compare hearing preservation rates after surgery for intracanalicular, small (0-20 mm), and large (>20 mm) tumors. Of 383 deduplicated articles, 26 studies (6.8%) met eligibility criteria for a total of 2034 patients with serviceable preoperative hearing, for whom postoperative hearing status was evaluated. Aggregate hearing preservation was 31% and 35% under a fixed and random effects model, respectively. A mixed effects model was used to determine hearing preservation rates depending on tumor size, which were determined to be 57%, 37%, and 12% for intracanalicular, small, and large tumors, respectively. Significant cross-study heterogeneity was found (I2=93%, τ2=.964, P<.01; Q=287.80, P=<.001), with rates of hearing preservation ranging from 0% to 100%. Tumor size may have an effect on hearing preservation rates, but multiple factors should be considered. Discussion of a patient's expectations for hearing preservation is critical when deciding on VS treatment plans.

Larger tumor size and female gender suggest better tinnitus prognosis after surgical treatment in vestibular schwannoma patients with tinnitus

Background: Tinnitus is a subjective auditory phantom phenomenon which can be highly distressing. About 63%–75% vestibular schwannoma (VS) had a symptom of tinnitus.Objectives: To investigate the tinnitus maintenance mechanism from the view of tinnitus change after surgical treatment in VS patients.Material and methods: We conducted a retrospective study of VS patients with tinnitus from August 2008 to February 2019 and did follow-ups on their changes of tinnitus after surgery.Results: Among 298 VS cases, 201 of them had tinnitus symptom (67.4%). No statistical difference in the surgical approach was found between the tinnitus poor outcome and good outcome groups (p = .14), and statistical difference was found in gender (p = .04) and tumor size (p = .01) between the two groups. Binary logistic regression analysis revealed that gender (odds ratio [OR], 2.12; 95% CI, 1.10–4.08 [p = .03]) and tumor size (OR, 2.22; 95% CI, 1.16–4.24 [p = .02]) emerged as a significant and independent factor associated with the good outcome of tinnitus.Conclusions and significance: The results of this study confirmed that the cochlear nucleus of the brainstem and above part of the brainstem may play an important role in the maintenance of tinnitus.

The emerging role of hearing loss rehabilitation in patients with vestibular schwannoma treated with Gamma Knife radiosurgery: literature review.

Stereotactic radiosurgery (SRS) is currently the most common treatment for small- to medium-size vestibular schwannoma (VS). Despite favorable outcome, hearing deterioration still remains an underestimated problem, and the role of hearing rehabilitation is an underinvestigated topic. Among available technologies, cochlear implant (CI) should represent a valid alternative in sporadic VS with single-sided deafness and in neurofibromatosis (NF2) with bilateral profound hearing loss. A literature review of the current clinical data was performed searching scientific literature databases. From all of the articles found, 16 papers were selected. Forty-four subjects treated with radiosurgery (18 male, 19 female, and in 7 cases, sex were not specified; 43 NF2 and 1 sporadic VS) were included in the analysis. Epidemiological, clinical, tumor, treatment, and audiological data were collected. Clinical outcome at last follow-up showed an audiological improvement in 25 of the 44 patients. The audiological outcome was unchanged in 16 cases. Audiological deterioration was recorded in 3 cases. Severity of NF2 phenotype, long history of ipsilateral profound deafness before implantation, progressive tumor growth, and high radiation dose (20 and 40Gy) were found in patients with a worst audiological outcome. Hearing rehabilitation can improve audiological results for VS patients following SRS in selected cases. Hearing rehabilitation with cochlear implant (CI) in SSD leads to partial restoration of binaural hearing with an improvement in speech comprehension in noise and in sound localization, and partial suppression of subjective incapacitating tinnitus. SRS followed by CI may represent in selected cases a potential emerging option in the management of these patients, aimed at improving their quality of life. Possible implications for the follow-up of these patients are still present, although partially resolved.

Quantifying Tertiary Referral Center Bias in Vestibular Schwannoma Research.

The majority of research influencing our understanding of vestibular schwannoma (VS) comes from large tertiary referral centers, and as a consequence, is inherently prone to referral bias. The objective of the current study was to characterize tertiary referral center bias in VS research. Single-institution retrospective clinical, audiometric, and radiologic review. One tertiary referral center. One hundred twenty-three patients with sporadic VS treated at our institution, consisting of a local cohort of all 41 VS patients residing in the same US county as our medical center and a referral cohort of 82 patients from outside counties matched 2:1 based on age, sex, and year of diagnosis. Surgical resection, stereotactic radiosurgery (SRS), observation. Clinical manifestations, audiometric and radiologic findings, elected treatment modality. Local patients had significantly longer follow-up after initial presentation compared to referral patients (median 4.0 vs 2.2 yr; p = 0.007). Referral patients were significantly less likely to have an incidental VS diagnosis (1% vs. 29%; p < 0.001) and presented with worse symptomatology such as hearing loss (80% vs. 54%; p = 0.002), dizziness (72% vs. 44%; p = 0.002), headache (29% vs. 15%; p = 0.075), and other cranial nerve dysfunction (11% vs. 0%; p = 0.029). Audiometrically, referral patients had significantly poorer word recognition scores at presentation (median 70% vs. 90%; p = 0.043). Local patients were more likely to have tumors confined to the IAC compared with referral patients, and had significantly smaller tumors when restricted to this region (median 4.0 vs 6.5 mm; p = 0.005). Referral patients were significantly more likely to undergo definitive management with either radiosurgery or microsurgery following primary evaluation compared to local patients (48% vs. 24%; p = 0.013). These data suggest that the majority of existing literature surrounding VS likely suffers from referral bias, whereby disease characteristics and management decisions are distinct from that of the general VS patient population.

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%.