Health-Related Quality of Life in Patients With a Stable or Growing Vestibular Schwannoma Managed by Wait and Scan or Stereotactic Radiosurgery.

OBJECTIVE: To assess the effect of wait and scan (W&S) and stereotactic radiosurgery (SRS) on health-related quality of life (HRQoL) over time in patients with a stable vestibular schwannoma (VS) and growing VS. STUDY DESIGN: Longitudinal, multicenter, observational study. SETTING: Tertiary expert center for VS (Radboudumc Nijmegen) and Gamma-Knife center ETZ Hospital Tilburg. METHODS: Changes in HRQoL, measured with the Penn Acoustic Neuroma Quality-of-Life (PANQOL), and the physical and mental component summary scores (PCS and MCS, respectively) derived from the 36-Item Short Form Health Survey (SF-36), were compared among patients managed by W&S and SRS between 2017 and 2022. Second, HRQoL over time in patients with a growing VS was compared between W&S and SRS. RESULTS: Differences in PANQOL total and subdomain scores, PCS and MCS scores over time in the W&S (n = 73) and SRS (n = 170) groups were nonsignificant and on average did not exceed the minimal clinically important differences (mean difference of -2.56 [PANQOL total], 1.22 [PCS], and -1.76 [MCS]; all P > .05). In growing VS, comparison of W&S (n = 29) and SRS (n = 154) also revealed no significant difference (mean difference of 1.19 (PANQOL total), 1.83 (PCS) and -0.12 (MCS); all P > .05). CONCLUSION: Differences in HRQoL in patients with VS are minor and not significantly different or clinically relevant between patients managed with W&S or SRS. Similarly, patients with a growing VS managed with W&S or SRS exhibit no significant or clinical relevant difference in HRQoL during follow-up. This can aid clinicians in the counseling of patients regarding HRQoL when deciding on a management strategy after diagnosis or documented growth.

Wait-and-scan management in sporadic Koos grade 4 vestibular schwannomas: A longitudinal volumetric study.

Background: Volumetric natural history studies specifically on large vestibular schwannomas (VSs), commonly classified as Koos grade 4, are lacking. The aim of the current study is to present the volumetric tumor evolution in sporadic Koos grade 4 VSs and possible predictors for tumor growth. Methods: Volumetric tumor measurements and tumor evolution patterns from serial MRI studies were analyzed from selected consecutive patients with Koos grade 4 VS undergoing initial wait-and-scan management between January 2001 and July 2020. The significant volumetric threshold was defined as a change in volume of ≥10%. Results: Among 215 tumors with a median size (IQR) of 2.7 cm3 (1.8-4.2), 147 tumors (68%) demonstrated growth and 75 tumors (35%) demonstrated shrinkage during follow-up. Growth-free survival rates (95% CI) at 1, 2, 5, and 10 years were 55% (48-61), 36% (29-42), 29% (23-36), and 28% (21-34), respectively and did not significantly differ in tumors> 20 mm (Chi-square = .40; P-value = .53). Four tumor evolution patterns (% of total) were observed: continued growth (60); initial growth then shrinkage (7); continued shrinkage (27); and stability (5). Good hearing (adjusted HR 2.21, 95% CI 1.48-3.30; P < .001) and peritumoral edema (adjusted HR 2.22, 95% CI 1.18-4.13; P = .01) at diagnosis were significantly associated with an increased likelihood of growth. Conclusions: Koos grade 4 VSs show a wide variety in size and growth. Due to variable growth patterns, an initial wait-and-scan strategy with short scan intervals may be an acceptable option in selected tumors, if no significant clinical symptoms of mass effect that warrant treatment are present.

What determines quality of life in patients with vestibular schwannoma?

OBJECTIVES: Patients with a vestibular schwannoma (VS) experience a reduced quality of life (QoL). The main objective of this study was to determine the strongest predictors reducing physical and mental QoL from the disease-specific Penn Acoustic Neuroma Quality of Life (PANQOL) questionnaire in patients with VS. DESIGN: Observational study. SETTING: Radboudumc Skull Base Centre, Nijmegen. PARTICIPANTS: Patients newly diagnosed with VS between 2014 and 2017 managed with either observation, stereotactic radiosurgery or microsurgery. MAIN OUTCOME MEASURES: Quality of life was assessed using the disease-specific PANQOL and general Short-Form (36) Health Survey (SF-36). Multiple linear regression models with PANQOL domains as predictors were used to determine the strongest predictors for SF-36 QoL physical and mental health scores. Standardised beta coefficients (ß) were used for ranking. RESULTS: A total of 174 patients (50% females, mean age 58.9 years) returned the questionnaires, providing a 69% response rate. Fifteen patients (9%) were treated with microsurgery, 29 (17%) with stereotactic radiosurgery and 130 patients (75%) were observed in a wait and scan strategy. A lack of energy (ß = .28; P ≤ .001), lower general health (ß = .22; P ≤ .001), headache (ß = .16; P ≤ .001), anxiety (ß = .15; P ≤ .001) and balance problems (ß = .10; P ≤ .001) are the strongest predictors affecting physical health, while mental health is most affected by anxiety (ß = .37; P ≤ .001), a lack of energy (ß = .34; P ≤ .001), facial nerve dysfunction (ß = .07; P ≤ .001), balance problems (ß = .04; P ≤ .001) and headaches (ß = .04; P ≤ .001). CONCLUSION: A lack of energy, anxiety, headache and balance problems are the strongest predictors of both SF-36 physical and mental QoL in patients with VS. More awareness and supportive care regarding energy, anxiety, headache and balance in informing, evaluating and treating patients with VS could improve QoL.

Development of a model to predict vestibular schwannoma growth: An opportunity to introduce new wait and scan strategies.

OBJECTIVES: To develop a prediction model to predict vestibular schwannoma (VS) growth for patients in a wait and scan (W&S) strategy. DESIGN: Retrospective cohort study. SETTING: Tertiary hospital (Radboud university medical center, Nijmegen, the Netherlands). PARTICIPANTS: Patients with unilateral VS, entering a W&S strategy and at least one follow-up MRI available. Data on demographics, symptoms, audiometry and MRI characteristics at time of diagnosis were collected from medical records. MAIN OUTCOME MEASURES: Following multiple imputation, a multivariable Cox regression model was used to select variables, using VS growth (≥2 mm) as outcome. Decision curve analyses (DCA) were performed to compare the model to the current strategy. RESULTS: Of 1217 analysed VS patients, 653 (53.7%) showed growth during follow-up. Balance complaints (HR 1.57 (95% CI: 1.31-1.88)) and tinnitus complaints in the affected ear (HR 1.36 (95% CI: 1.15-1.61)), Koos grade (Koos 1 is reference, Koos 2 HR 1.03 (95% CI: 0.80-1.31), Koos 3 HR 1.55 (95% CI: 1.16-2.06), Koos 4 HR 2.18 (95% CI: 1.60-2.96)), time since onset of symptoms (IQR HR 0.83 (95% CI: 0.77-0.88) and intrameatal diameter on MRI (IQR HR 1.67 (95% CI: 1.42-1.96)) were selected as significant predictors. The model's discrimination (Harrell's C) was 0.69 (95% CI: 0.67-0.71), and calibration was good. DCA showed that the model has a higher net benefit than the current strategy for probabilities of VS growth of >12%, 15% and 21% for the first consecutive 3 years, respectively. CONCLUSIONS: Patients with balance and tinnitus complaints, a higher Koos grade, short duration of symptoms and a larger intrameatal diameter at time of diagnosis have a higher probability of future VS growth. After external validation, this model may be used to inform patients about their prognosis, individualise the W&S strategy and improve (cost-)effectiveness.

Radiomics-Based Prediction of Long-Term Treatment Response of Vestibular Schwannomas Following Stereotactic Radiosurgery.

OBJECTIVE: Stereotactic radiosurgery (SRS) is one of the treatment modalities for vestibular schwannomas (VSs). However, tumor progression can still occur after treatment. Currently, it remains unknown how to predict long-term SRS treatment outcome. This study investigates possible magnetic resonance imaging (MRI)-based predictors of long-term tumor control following SRS. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: Analysis was performed on a database containing 735 patients with unilateral VS, treated with SRS between June 2002 and December 2014. Using strict volumetric criteria for long-term tumor control and tumor progression, a total of 85 patients were included for tumor texture analysis. INTERVENTION(S): All patients underwent SRS and had at least 2 years of follow-up. MAIN OUTCOME MEASURE(S): Quantitative tumor texture features were extracted from conventional MRI scans. These features were supplied to a machine learning stage to train prediction models. Prediction accuracy, sensitivity, specificity, and area under the receiver operating curve (AUC) are evaluated. RESULTS: Gray-level co-occurrence matrices, which capture statistics from specific MRI tumor texture features, obtained the best prediction scores: 0.77 accuracy, 0.71 sensitivity, 0.83 specificity, and 0.93 AUC. These prediction scores further improved to 0.83, 0.83, 0.82, and 0.99, respectively, for tumors larger than 5 cm. CONCLUSIONS: Results of this study show the feasibility of predicting the long-term SRS treatment response of VS tumors on an individual basis, using MRI-based tumor texture features. These results can be exploited for further research into creating a clinical decision support system, facilitating physicians, and patients to select a personalized optimal treatment strategy.

Hearing Results of Surgery for Acquired Atresia of the External Auditory Canal.

OBJECTIVE: To evaluate short- and long-term hearing results of surgery for acquired atresia of the external auditory canal (EAC) in a large patient cohort and to define preoperative audiometric conditions useful for patient counseling. STUDY DESIGN: Retrospective cohort study. SETTING: Academic tertiary referral center. PATIENTS: Seventy-eight ears from 72 patients with postinflammatory acquired atresia of the EAC who underwent canal- and meatoplasty were included. Patients with involvement of the ossicular chain, (syndromic) external ear malformations, or congenital aural atresia were excluded. INTERVENTION: Canal- and meatoplasty. MAIN OUTCOME MEASURES: Mean pure-tone averages of thresholds at 0.5, 1, 2, and 3 kHz (PTA0.5,1,2,3) for air conduction (AC), bone conduction, and air-bone gap (ABG) were calculated preoperatively and at short-term (≤0.55 yr) and long-term follow-up (>0.55 yr). Additionally, the numbers of ears with a closed ABG ≤10 dB and ≤20 dB, and with Social hearing (defined as: AC PTA0.5,1,2,3 ≤35 dB) were assessed. RESULTS: At short-term follow-up AC PTA0.5,1,2,3 improved by 18 dB. Social hearing was obtained in 81% of the ears. Postoperatively, 35% of the ears had a closed ABG ≤10 dB, 83% was closed ≤20 dB. During follow-up, significant deterioration of 5 to 7 dB occurred for AC thresholds at 0.25, 0.5, and 1 kHz. CONCLUSIONS: Surgery for acquired atresia of the EAC is often beneficial. This study suggests overall advantageous surgery when the preoperative indication criteria ABG PTA0.5,1,2,3 >20 dB and AC PTA0.5,1,2,3 >35 dB are applied.

Influence of pretreatment growth rate on Gamma Knife treatment response for vestibular schwannoma: a volumetric analysis.

OBJECTIVEThe aim of this study was to gain insight into the influence of the pretreatment growth rate on the volumetric tumor response and tumor control rates after Gamma Knife radiosurgery (GKRS) for incidental vestibular schwannoma (VS).METHODSAll patients treated with GKRS at the Gamma Knife Center, ETZ Hospital, who exhibited a confirmed radiological progression of their VS after an initial observation period were included. Pre- and posttreatment MRI scans were volumetrically evaluated, and the volume doubling times (VDTs) prior to treatment were calculated. Posttreatment volumes were used to create an objective mathematical failure definition: 2 consecutive significant increases in tumor volume among 3 consecutive follow-up MRI scans. Spearman correlation, Kaplan-Meier survival analysis, and Cox proportional hazards regression analysis were used to determine the influence of the VDT on the volumetric treatment response.RESULTSThe resulting patient cohort contained 311 patients in whom the VDT was calculated. This cohort had a median follow-up time of 60 months after GKRS. Of these 311 patients, 35 experienced loss of tumor control after GKRS. The pretreatment growth rate and the relative volume changes, calculated at 6 months and 1, 2, and 3 years following treatment, showed no statistically significant correlation. Kaplan-Meier analysis revealed that slow-growing tumors, with a VDT equal to or longer than the median VDT of 15 months, had calculated 5- and 10-year control rates of 97.3% and 86.0%, respectively, whereas fast-growing tumors, with a VDT less than the median growth rate, had control rates of 85.5% and 67.6%, respectively (log-rank, p = 0.001). The influence of the VDT on tumor control was also determined by employing the Cox regression analysis. The resulting model presented a significant (p = 0.045) effect of the VDT on the hazard rates of loss of tumor control.CONCLUSIONSBy employing a unique, large database with long follow-up times, the authors were able to accurately investigate the influence of the pretreatment VS growth rate on the volumetric GKRS treatment response. The authors have found a predictive model that illustrates the negative influence of the pretreatment VS growth rate on the efficacy of radiosurgery treatment. The resulting tumor control rates confirm the high efficacy of GKRS for slow-growing VS. However, fast-growing tumors showed significantly lower control rates. For these cases, different treatment strategies may be considered.

Risk factors for complications in cochlear implant surgery.

PURPOSE: The objective of this study was to achieve uniform reporting of complications and failures in cochlear implantation, to analyze complications and failures and to identify risk factors for complications in a series of over 1300 cochlear implantations. METHODS: In a retrospective chart review and observational study, data from all cochlear implantations from 1987 to 2015 were entered in a custom-made database. Complications were classified using the contracted form of the Clavien-Dindo system and risk factors were identified by statistical analysis. RESULTS: A complication rate of 18.4% and a device failure rate of 2.9% were found. There was a higher rate of hematoma in patients with a clotting disorder and when a subtotal petrosectomy was performed, a higher rate of wound infections in patients who were not vaccinated against Streptococcus pneumoniae and a higher rate of meningitis in patients with an inner ear malformation. CONCLUSIONS: The use of a strict definition of a medical complication and device failure-in combination with the Clavien-Dindo classification system-enables uniform and objective registration of adverse events and prevents any tendency to downgrade complications. Complication and failure rates in this series are comparable to those reported in the literature. These results stress the need for pneumococcal vaccination, which may prevent general wound infections, but is especially important for patients with inner ear malformation, who have an increased risk of (postoperative) meningitis.

Retreatment of vestibular schwannoma with Gamma Knife radiosurgery: clinical outcome, tumor control, and review of literature.

OBJECTIVE Gamma Knife radiosurgery (GKRS) has become an accepted treatment for vestibular schwannoma, with a high rate of tumor control and good clinical outcome. In a small number of cases, additional treatment is needed. This retrospective study examines the clinical outcome, reproducibility of volumetric response patterns, and tumor control rate after administering a second GKRS to treat vestibular schwannomas. METHODS A total of 38 patients were included: 28 patients underwent a radiosurgical procedure as the initial treatment (Group 1), and 10 patients underwent microsurgical resection with adjuvant radiosurgery on the tumor remnant as the initial treatment (Group 2). The indication for a second GKRS treatment was growth observed on follow-up imaging. The median margin dose was 11.0 Gy for the first procedure and 11.5 Gy for the second procedure. Tumor control after retreatment was assessed through volumetric analysis. Clinical outcome was assessed through medical chart review. RESULTS Median tumor volume at retreatment was 3.6 cm3, with a median treatment interval of 49 months. All patients showed tumor control in a median follow-up period of 75 months after the second radiosurgical procedure. Volumetric tumor response after the second procedure did not correspond to response after the first procedure. After retreatment, persisting House-Brackmann Grade II facial nerve dysfunction was observed in 3 patients (7.9%), facial spasms in 5 patients (13%), and trigeminal nerve hypesthesia in 3 patients (7.9%). Hearing preservation was not evaluated because of the small number of patients with serviceable hearing at the second procedure. CONCLUSIONS Repeat GKRS after a failed first treatment appears to be an effective strategy in terms of tumor control. The volumetric response after a repeat procedure could not be predicted by the volumetric response observed after first treatment. This justifies considering repeat GKRS even for tumors that do not show any volumetric response and show continuous growth after first treatment. An increased risk of mild facial and trigeminal nerve dysfunction was observed after the second treatment compared with the first treatment.

Active Middle Ear Implantation: Long-term Medical and Technical Follow-up, Implant Survival, and Complications.

OBJECTIVE: To evaluate the long-term medical and technical results, implant survival, and complications of the semi-implantable vibrant soundbridge (VSB), otologics middle ear transducer (MET), and the otologics fully implantable ossicular stimulator (FIMOS). STUDY DESIGN: Retrospective cohort study. PATIENTS: Patients with chronic external otitis and either moderate to severe sensorineural or conductive/mixed hearing loss. SETTING: Tertiary referral center. INTERVENTION: Implantation with the VSB, MET, or FIMOS. MAIN OUTCOME MEASURES: Medical complications, number of reimplantations, and explantations. RESULTS: Ninety-four patients were implanted, 12 patients with a round window or stapes application. 28 patients were lost to follow-up. The average follow-up duration was 4.4 years (range, 1 month-15 years). 128 devices were evaluated: (92 VSB, 32 MET, 4 FIMOS). 36 devices (28%) have been explanted or replaced (18 VSB, 14 MET, 4 FIMOS). Device failure was 7% for VSB, 28% for MET, and 100% for FIMOS. In 16 patients (17%) revision surgery (n = 20) was performed. Twenty patients (21%) suffered any medical complication. CONCLUSION: Medical and technical complications and device failures have mostly occurred in the initial period of active middle ear implants (AMEI) implementation and during clinical trials or experimental procedures. All four FIMOS had technical difficulties. An important decrease in the occurrence of both medical and technical complications was observed. Application in more recent years did not show any complications and the recent device failure rates are acceptable. Magnetic resonance imaging (MRI) incompatibility should be taken into account when indicating AMEI.

Gamma Knife radiosurgery for vestibular schwannomas: evaluation of tumor control and its predictors in a large patient cohort in The Netherlands.

OBJECT The authors of this study sought to assess tumor control and complication rates in a large cohort of patients who underwent Gamma Knife radiosurgery (GKRS) for vestibular schwannoma (VS) and to identify predictors of tumor control. METHODS The records of 420 patients treated with GKRS for VS with a median marginal dose of 11 Gy were retrospectively analyzed. Patients with neurofibromatosis Type 2 or who had undergone treatment for VS previously were excluded. The authors assessed tumor control and complication rates with chart review and used the Cox proportional hazards model to identify predictors of tumor control. Preservation of serviceable hearing, defined as Gardner-Robertson Class I-II, was evaluated in a subgroup of 71 patients with serviceable hearing at baseline and with available follow-up audiograms. RESULTS The median VS tumor volume was 1.4 cm(3), and the median length of follow-up was 5.1 years. Actuarial 5-and 10-year tumor control rates were 91.3% and 84.8%, respectively. Only tumor volume was a statistically significant predictor of tumor control rate. The tumor control rate decreased from 94.1% for tumors smaller than 0.5 cm(3) to 80.7% for tumors larger than 6 cm(3). Thirteen patients (3.1%) had new or increased permanent trigeminal nerve neuropathy, 4 (1.0%) had new or increased permanent facial weakness, and 5 (1.2%) exhibited new or increased hydrocephalus requiring a shunting procedure. Actuarial 3-year and 5-year hearing preservation rates were 65% and 42%, respectively. CONCLUSIONS The 5-year actuarial tumor control rate of 91.3% in this cohort of patients with VS compared slightly unfavorably with the rates reported in other large studies, but the complication and hearing preservation rates in this study were similar to those reported previously. Various factors may contribute to the observed differences in reported outcomes. These factors include variations in treatment indication and in the definition of treatment failure, as well as a lack of standardization of terminology and of evaluation of complications. Last, differences in dosimetric variables may also be an explanatory factor.

Avastin scintigraphy in surveillance of bevacizumab treatment in a patient with neurofibromatosis type 2: a case report.

A patient with neurofibromatosis type 2 (bilateral vestibular schwannomas) was treated with bevacizumab (anti-vascular endothelial growth factor [VEFG] monoclonal antibody). The left-sided tumor showed intense uptake on pretreatment In-bevacizumab scintigraphy, indicating VEGF production in the tumor, and no uptake 4 weeks later, demonstrating effective binding of nonradiolabeled bevacizumab to the VEGF produced in the tumor. The right-sided tumor showed no tracer uptake at any time point. Significant tumor volume reduction (assessed with MRI) and hearing improvement were observed on the left side. In-bevacizumab scintigraphy may be a promising upfront patient selection tool to identify patients who may benefit from expensive bevacizumab treatment.

Radiation therapy for vestibular schwannomas.

PURPOSE OF REVIEW: Recently, new information on the natural course and on the results of radiation therapy of vestibular schwannomas has been published. The aim of this study is to summarize the most recent literature on the contemporary insights on the natural course and the results of the latest strategies of radiotherapy for vestibular schwannomas. RECENT FINDINGS: After diagnosis only about one-third of all vestibular schwannomas will progress. Many patients do well with a 'wait and see' policy and, when necessary, radiation treatment has the advantage that tumor control rates are high (95%) and treatment-related side effects are very low. Different approaches to radiotherapy continue to evolve. Up till now stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) yield comparable results both in terms of tumor control and cranial nerve preservation. With new data available on hearing preservation after radiotherapy, a watchful waiting policy is a renewed matter of debate. SUMMARY: When a vestibular schwannoma grows, radiotherapy (SRS or FSRT) may be a valuable treatment modality. Future clinical research (properly designed randomized trials) should focus on when and when not to treat, even if a vestibular schwannoma is not growing and on potential differences in long-term effects between SRS and fractionated radiotherapy.

Application of active middle ear implants in patients with severe mixed hearing loss.

OBJECTIVE: To determine the long-term benefit of the Vibrant Soundbridge (VSB) middle ear implant in patients with severe mixed hearing loss and to compare it with other hearing devices. DESIGN: A retrospective analysis. SETTING: University-affiliated medical center. PATIENTS: Six patients with severe mixed hearing loss and a mean sensorineural hearing loss component between 40 and 70 dB. INTERVENTIONS: Patients received a VSB with the floating mass transducer (FMT) coupled to the round window or to the oval window via a residual stapes structure. MAIN OUTCOME MEASURES: Functional gain and speech recognition results. Results are compared with 2 control groups matched for mean sensorineural hearing loss: 1) patients with mixed hearing loss and a bone-anchored hearing device, and 2) patients with sensorineural hearing loss and traditional implantation of the VSB. RESULTS: There is large variance in functional gain between the patients suggesting high variability in the effectivity of the FMT coupling. The speech recognition results for the experimental group were not systematically better than in either control group. CONCLUSION: There is large variability in results that might be ascribed to coupling effectivity. On the average, speech recognition results were not better or worse than those found in patients with similar hearing loss fitted with bone-anchored hearing devices.

Gamma knife radiosurgery for vestibular schwannomas: identification of predictors for continued tumor growth and the influence of documented tumor growth preceding radiation treatment.

OBJECTIVES/HYPOTHESIS: Gamma knife radiosurgery (GKRS) has become an important treatment modality for vestibular schwannomas. The primary aim of this study was to investigate whether tumor growth at the moment of GKRS has any correlation with the outcome. The secondary aim was to identify clinical predictors of radioresistance in vestibular schwannoma patients treated with GKRS. STUDY DESIGN: One hundred vestibular schwannoma patients, treated with GKRS, were divided into two groups: 1) proven tumor growth preceding GKRS; and 2) previous history of growth unknown. GKRS outcome was defined in two ways. According to the first definition, GKRS was said to have failed when additional treatment had taken place. According to the second one, a volume decrease >20% after 2 years marked successful treatment. METHODS: Correlations between outcome and growth status were determined with SPSS software. Furthermore, the study assessed how different variables (patient data, history, tumor characteristics, imaging, and audiovestibular examinations) correlated with the outcome of GKRS. RESULTS: No significant difference regarding success and failure of GKRS was found between the two patient groups. The mean reduction in tumor volume after GKRS was less pronounced in patients in whom tumor growth was demonstrated before treatment, but this finding was not significant. No significant predictors (P < .05) could be identified in this data set. CONCLUSIONS: This study found no indication that growth at the moment of GKRS influences therapeutic outcome, nor did it identify any predictors of the outcome after GKRS in vestibular schwannoma patients.

Follow-up after gamma knife radiosurgery for vestibular schwannomas: volumetric and axial control rates.

OBJECTIVES/HYPOTHESIS: A prospective long-term follow-up study was conducted to evaluate the results of gamma knife radiosurgery (GKRS) for vestibular schwannoma (VS) patients. Both axial and volumetric measurements are used to determine tumor size during follow-up. STUDY DESIGN: Individual prospective cohort study. METHODS: A total of 110 VS patients were referred for radiosurgery between 2002 and 2007. All patients were treated with a Leksell 4C gamma knife. There were 12.5 to 13 Gy prescribed to the isodose covering 90% of the tumor volume. The resulting marginal dose was on average 11.0 Gy (range, 9.3-12.5 Gy). Tumor size and tumor volume were determined before and after gamma knife treatment at regular intervals. The minimal follow-up period was 2 years. RESULTS: There were 100 patients included in the study. Eight patients needed additional treatment after a mean follow-up period of 38 months. One patient experienced a temporary facial nerve deficit. No growth pattern could be recognized for tumor growth after GKRS. Based on the measurements of the largest extrameatal diameter, the tumor size would have decreased or remained stable in 94%. Based on volumetric measurement, the tumor size was decreased or remained stable in 79%. CONCLUSIONS: High tumor control and low complication rates make GKRS a good therapy for VS. If tumor growth occurs after GKRS, a conservative management can be considered because continued tumor growth is uncertain. The extrameatal diameter on axial magnetic resonance imaging seems to be a reliable parameter of the size of a VS. Volumetry is the preferred method to assess the dimensions of a VS, although the consequences of strong volumetric increase, especially in small tumors, can be different depending on individual differences in tumor size.

Endolymphatic sac tumors: clinical outcome and management in a series of 9 cases.

OBJECTIVES: Endolymphatic sac tumors (ELSTs) are rare adenomatous tumors arising in the petrous bone, either spontaneously (isolated) or in association with von Hippel-Lindau (VHL) disease. For 9 patients, this study describes the typical features and management of ELST and the clinical outcome of treatment. Similarities and differences are identified for ELST in isolation and in association with VHL disease. STUDY DESIGN: Case series. SETTING: Tertiary referral center. PATIENTS: The patient database was searched for patients diagnosed with ELST. All other tertiary referral centers in The Netherlands were invited to do likewise. INTERVENTIONS: The patient records were screened for presenting symptoms, hearing, imaging, treatment, and treatment outcome. Histopathologic finding was reviewed by a senior pathologist. RESULTS: Six patients with an isolated ELST and 3 patients with an ELST in association with VHL disease were identified. In the isolated ELST group, 5 patients were treated surgically and 1 patient was administered primary radiotherapy. In the VHL group, 1 patient underwent surgery and 2 patients were treated conservatively after a wait-and-magnetic resonance imaging-scan protocol. All individual treatment outcomes are scrupulously presented in this article. CONCLUSION: This study compiles and describes 9 cases of ELST. In 8 of 9 patients, the ELST could be controlled by surgery, radiotherapy, or a wait-and-scan protocol. The large interpatient differences make it difficult to standardize the management of this disease. The management is strongly influenced by comorbidity and tumor stage.

A surgical technique for implantation of the vibrant soundbridge middle ear implant in dogs.

OBJECTIVE: To report a surgical implantation of the Vibrant Soundbridge (VSB) middle ear implant in dogs. STUDY DESIGN: Pilot study. ANIMALS: Dogs (n=3). METHODS: A lateral approach to the tympanic bulla was used to insert the floating mass transducer of the VSB into the tympanic bulla. Using microscopic guidance the transducer was moved to and inserted into the round window niche by manipulation through the acoustic bony meatus, after reflection of the tympanic membrane. VSB position was confirmed by computed tomography (CT) imaging. RESULTS: No intraoperative complications occurred and CT images confirmed correct placement of the VSB. CONCLUSIONS: A VSB can be safely implanted in the middle of dogs.

Vibrant Soundbridge surgery in patients with severe external otitis: complications of a transcanal approach.

OBJECTIVE: To evaluate the transcanal surgical implantation of the semi-implantable Vibrant Soundbridge (VSB) device in patients with severe external otitis. STUDY DESIGN: Retrospective analysis. METHODS: Long-term postoperative complications and postoperative hearing thresholds were evaluated in 13 adults with bilateral sensorineural hearing loss (average of between 40 and 55 dB HL) and therapy-resistant external otitis after implantation of the VSB by a transcanal surgical method. RESULTS: Postoperative audiometry findings were comparable with those reported after the transmastoidal posterior tympanotomy approach. In 2 patients, the chorda tympani was intentionally sacrificed to maximize the size of the facial recess. Seven postoperative complications occurred in 6 patients (46%) during a mean follow-up period of 51 months: extrusion of the conducting wire into the ear canal (n=5), collapse of the cartilaginous part of the ear canal (n=1), and tympanic membrane perforation (n=1). In the revision operations that added additional layers of fascia for the patients with wire extrusions, repeated extrusion occurred in 3 of 4 cases. CONCLUSION: The transcanal approach for the implantation of the VSB has led to postoperative complications different from those reported after the transmastoidal posterior tympanotomy approach. External otitis should be considered as a contraindication for VSB surgery by the transcanal approach.

Prediction of vestibular schwannoma growth: a novel rule based on clinical symptomatology.

OBJECTIVES: The aim of this study was to formulate a predictive rule for vestibular schwannoma growth during the initial observation period after diagnosis. METHODS: Logistic regression models were fitted, with tumor growth in the first year as the dependent variable and patient characteristics as the independent variables. Backward selection was used to eliminate superfluous predictors. The area under the receiver operating characteristic curve was taken as a measure of the model's discriminative power. RESULTS: Eventually, the model or rule consisted of 4 significant growth predictors: localization (if extrameatal, +1; if intrameatal, 0), sudden sensorineural hearing loss (if present, -1; if absent, 0), balance symptoms (if present, +1; if absent, 0), and complaints of hearing loss for less than 2 years (if present, +1; if absent, or present for more than 2 years, 0). A higher score indicates a higher likelihood of tumor growth during the period of observation after diagnosis. If the total score is 0 or less, the likelihood of tumor growth during the first year after diagnosis is less than 10%. If the score is 3, the likelihood of growth during the first year after diagnosis is more than 70%. CONCLUSIONS: We were able to create a useful rule to predict vestibular schwannoma growth during the first year after diagnosis.