Schwannoma Patients Research Articles

(8)Treatment Strategy of Vestibular Schwannomas in Patients with Neurofibromatosis Type 2:A Neurosurgeon's Perspective

(8)Treatment Strategy of Vestibular Schwannomas in Patients with Neurofibromatosis Type 2:A Neurosurgeon's Perspective

Linked-read Sequencing Analysis Reveals Tumor-specific Genome Variation Landscapes in Neurofibromatosis Type 2 (NF2) Patients.

We hypothesize that genomic variants including deletions, insertions, inversions, and tandem duplications beyond the changes in tumor suppressor NF2 gene affect gene expression of tumor-specific pathways in vestibular schwannomas (VS) patients with Neurofibromatosis type 2 (NF2), thus contributing to their clinical behavior. Genomic variation could reconfigure transcription in NF2 transformation process. Therefore, genome-wide high-resolution characterization of structural variants (SV) landscapes in NF2 tumors can expand our understanding of the genes regulating the clinical phenotypes in NF2-associated VS. We performed whole-genome haplotype-specific structural variation analysis using synthetic linked reads generated through microfluidics-based barcoding of high molecular weight DNA followed by high-coverage Illumina paired-end whole-genome sequencing from 10 patients' tumors of different growth rates and their matching blood samples. NF2 tumor-specific deletions and large SVs were detected and can be classified based on their association with tumor growth rates. Through detailed annotation of these mutations, we uncover common alleles affected by these deletions and large SVs that can be associated with signaling pathways implicated in cell proliferation and tumorigenesis. The genomic variation landscape of NF2-related VS was investigated through whole-genome linked-read sequencing. Large SVs, in addition to deletions, were identified and may serve as modulators of clinical behavior.

Cochlear Implantation in Sporadic Vestibular Schwannoma: A Systematic Literature Review.

Objective This study was aimed to perform a systematic literature review by examining outcomes in patients with sporadic vestibular schwannoma (VS) undergoing ipsilateral cochlear implant (CI). Data Sources PubMed-NCBI (National Center for Biotechnology Information) and Scopus databases were searched through October 2017. Study Selection Studies reporting auditory outcomes for each patient when a CI was placed with an ipsilateral sporadic VS were included. Main Outcome Measures Demographic variables, VS characteristics, preoperative hearing metrics, duration of deafness, CI type, approach to tumor resection, postoperative auditory outcomes, and postoperative tinnitus outcomes were reported for each eligible patient within studies. Each study was evaluated for quality and bias. Results Fifteen studies and 45 patients met inclusion criteria. Mean speech discrimination score (SDS) improved from 30.0 to 56.4% after CI placement. The majority when reported had an improvement in tinnitus. Preoperative ipsilateral SDS was a negative predictor of postoperative SDS, while neither tumor resection status, tumor location, duration of deafness, ipsilateral pure tone average, nor timing of CI placement had a significant effect on patient outcome. Conclusions Notwithstanding the challenges inherent with surveillance magnetic resonance imaging (MRI) in the setting of a cochlear implant magnet, select sporadic vestibular schwannoma patients can be considered for cochlear implantation.

Otolith Function Testing.

Two technically simple tests, vestibular evoked myogenic potential (VEMP) and subjective visual vertical/horizontal (SVV/H) test, have the potential to transform otolith function testing from the research laboratory to the outpatient clinic. Cervical- and ocular-VEMPs are short latency surface potentials produced through the activation of saccular and utricular afferents by sound and vibration. They are tests of dynamic otolith function. The SVV/H test in peripheral lesions probes static asymmetries in utricular function and represents a perceptual error in perceived gravitational vertical/horizontal. VEMPs and SVV/H enable the characterization of patterns and severity of otolith dysfunction in common vestibular disorders. Combined with tests of semicircular canal function, they provide a useful tool for eliciting diagnostic profiles in vestibular neuritis and Ménière's disease. VEMPs are valuable in the pre-surgical confirmation of superior semicircular canal dehiscence and in some cases, may alert the clinician to the presence of a vestibular schwannoma in patients with symmetrical hearing.

Clinical, radiological and toxicity evaluation of Vestibular Schwannoma patients treated with Cyberknife® stereotactic radiosurgery-radiotherapy

Clinical, radiological and toxicity evaluation of Vestibular Schwannoma patients treated with Cyberknife® stereotactic radiosurgery-radiotherapy

Preservation of Hearing and Facial Nerve Function with the Microsurgical Excision of Large Vestibular Schwannomas: Experience with the Retrosigmoid Approach.

IntroductionVestibular schwannomas (VS) are the most common benign neoplasms of a cerebellopontine angle (CPA), which arise from the Schwann cells of the vestibulocochlear nerve. Eighty percent of CPA tumors are VS followed by meningioma as the second common mass lesion in this critical potential space. Treatment options range from watchful waiting with serial imaging studies to radiosurgery or a microsurgical excision or a combination of surgery and radiation therapy. The primary objective of the study was to assess hearing and facial nerve status before and after the surgery via the retrosigmoid approach.MethodsThe database of Aga Khan University Hospital was searched for diagnoses of vestibular schwannomas between 2000 and 2007. A total of 35 patients were identified; among them, 27 were selected for the study who met the inclusion criteria. The variables of the study were age, gender, presenting symptoms, size of the tumor, surgical approach, hearing levels, and facial nerve function. Hearing loss was categorized according to the Gardener-Robertson hearing classification and the House-Brackmann Scale was used for facial nerve assessment.ResultsOut of the 27 patients, 18 were male and nine were female. The mean age was 43 years. The most common presenting complaint was hearing loss and tinnitus, seen in 21 patients. Headache was present in six patients, ataxia in five, and vertigo in three. Facial nerve weakness was noticed in six patients. Two patients had Grade-III paralysis, three had Grade-IV paralysis, and one had Grade-V paralysis. The audiogram confirmed the presence of sensorineural hearing loss (SNHL) in all patients. Twelve patients out of 27 had Class II hearing with the threshold between 31 and 50 decibels and a Speech Discrimination Score (SDS) of 50% to 69%. Ten patients had non-serviceable hearing and the remaining five had poor hearing. The audiogram was repeated after surgery for those 12 patients who had Class II hearing and showed that seven out of 12 patients maintained a hearing threshold within the range of Class II at the one-year follow-up (hearing preservation 58%). The facial nerve preservation rate was 56% considering House-Brackmann Grade III or less as acceptable facial nerve function.ConclusionThe optimal treatment for small vestibular schwannomas is a matter of controversy; however, the choice of treatment for large vestibular schwannomas in patients without significant comorbidity is generally microsurgical excision. The surgical excision of a large VS with the retrosigmoid approach is found to be safe consistently. The hearing and facial nerve preservation in our study were found comparable with the literature.

Comparison of cervical vestibular evoked potentials evoked by air-conducted sound and bone-conducted vibration in vestibular Schwannoma patients

Objective: The vestibular evoked myogenic potential (VEMP) is associated with otolithic afferents and can be used to evaluate the function of the saccule and utricle. In this study, we compared cervical VEMP evoked by stimulation with Air-conducted sound (ACS) and bone-conducted vibration (BCV) to the forehead and investigated whether BCV can be used as a substitute for ACS.Methods: Data were obtained from 33 patients with vestibular schwannoma. Vestibular examinations were performed preoperatively. VEMP was obtained upon stimulation with ACS (ACS cVEMP) and BCV to the forehead using a minishaker (BCV cVEMP). Vestibular function was also analyzed using the caloric test and ocular VEMP (oVEMP) testing. oVEMP was measured using bone-conductive vibration to the forehead. The results of BCV cVEMP, ACS cVEMP, and oVEMP were compared by the caloric test.Results: Rates of patients with abnormal ACS cVEMP, BCV cVEMP, oVEMP, and caloric test results were 78.8%, 75.8%, 78.8%, and 69.7%, respectively. BCV cVEMP did not correlate with ACS cVEMP, but correlated with oVEMP and caloric test results.Conclusion: BCV cVEMP did not correlate with ACS cVEMP. Therefore, BCV cVEMP cannot be used as a substitute for ACS cVEMP.

Hearing Outcomes in Conservatively Managed Vestibular Schwannoma Patients With Serviceable Hearing.

To characterize the risk of progression to nonserviceable hearing in patients with sporadic vestibular schwannomas (VS) who elect initial observation. Retrospective case series. Two tertiary care centers. VS patients with serviceable hearing who underwent at least two audiograms and two MRI studies before intervention or loss to follow-up. Serviceable hearing, defined as the pure tone average ≤ 50 dB HL and word recognition score ≥ 50%. Four-hundred sixty-six patients (median age of 57 yr and median tumor diameter of 7.3 mm) had serviceable hearing at presentation and were followed for a median of 2.3 years (IQR 1.0 - 4.0). Kaplan-Meier estimated rates of maintaining serviceable hearing (95% CI; number still at risk) at 1, 3, 5, 7, and 10 years following diagnosis were 94% (91-96; 357), 77% (73-82; 172), 66% (60-73; 81), 56% (49-65; 31), and 44% (33-59; 10), respectively. Each 10-dB increase in pure-tone averages at diagnosis was associated with a 2-fold increased likelihood of developing nonserviceable hearing (hazard ratio 2.07; p < 0.001). Each 10% decrease in word recognition score was associated with a 1.5-fold increased likelihood of developing nonserviceable hearing (hazard ratio 1.48; p < 0.001). Among patients with sporadic VS, good baseline word recognition score and low pure-tone average are jointly associated with maintenance of serviceable hearing. These data may be used to guide patient counseling and optimize management.

Quality of life in the management of small vestibular schwannomas: Observation, radiotherapy and microsurgery.

The aim of this study was to compare quality of life (QOL) in small unilateral vestibular schwannoma (VS) patients managed by microsurgery, radiotherapy or observation. A retrospective chart review. The study included a total of 142 patients with VS stage 1 or 2 according to the Koos classification and treated between January 2004 and December 2015. Microsurgery, radiotherapy and observation groups comprised 43, 46 and 53 patients, respectively. All patients completed four QOL (questionnaires: Short-Form Health Survey 36, Hearing Handicap Inventory, Tinnitus Handicap Inventory and Dizziness Handicap Inventory Short-Form). Clinical symptoms and QOL were compared among groups. The average time interval between management and filling in the questionnaires was 66months. There was no difference in QOL between the three groups on any of the four questionnaires. The most debilitating symptom was vertigo for all three groups. Tinnitus was a pejorative factor in the surgery group. Hearing level was deteriorated after microsurgery but there was no significant difference between the radiotherapy group and the middle fossa approach. Patients with small VS stage 1 and 2 had similar QOL, irrespective of management by observation, radiotherapy or microsurgery. The overall predictor for long-term reduced QOL was vertigo. Vestibular rehabilitation could improve QOL in symptomatic patients.

Maximizing Exposure of the Internal Auditory Canal Via the Retrosigmoid Approach: An Anatomical, Radiological, and Surgical Study.

The purpose of this study was to identify anatomic landmarks and surgical techniques that maximize bone removal for exposure of the distal internal auditory canal (IAC) to avoid labyrinthine injury during retrosigmoid removal of tumors within the IAC. Anatomic dissection, radiological assessment and retrospective case series. Tertiary referral center. On the basis of previously conducted temporal bone anatomic dissections of the temporal bone, the authors performed intraoperative measurement of the undissected distal IAC, performed pre- and postoperative radiological assessment of vestibular schwannoma (VS) patients. The surgical and anatomic information was used to determine the anatomic limits of labyrinth sparing bone dissection and the landmarks most critical to maximal IAC exposure. The authors describe surgical techniques using these data. An edited video of representative surgery highlights important principles. Review of 251 patients requiring IAC bony dissection for tumor removal from January 2005 through October 2017 is described. Achieving complete exposure of the IAC fundus is not possible, without labyrinthine injury, via retrosigmoid approach. Anatomic dissection, intraoperative photography, and postoperative radiographs demonstrate that bone removal within 2 to 3 mm of the fundus is routinely possible. The endolymphatic sac and duct is the optimal landmark for optimizing IAC exposure. The course of the endolymphatic sac and duct in the posterior petrous bone is the most important landmark determining the lateral limit of bony removal during IAC exposure for tumor resection. Surgical techniques based on these anatomic findings facilitate tumor resection while preserving the labyrinth.

P264] Time resolved dose rate distributions in radiosurgery and their impact on biological effectiveness of treatment

Purpose To obtain time-resolved dose rate distributions (TR-DRD) in radiosurgery applications, and evaluate the impact of TR-DRD on the biological effectiveness of treatment. Methods Treatment plans of 74 acoustic schwannoma patients treated with Leksell Gamma Knife® C or PERFEXION™ were meta-analyzed. The 3D dose distribution within the Planning Target Volume (PTV) for each patient was obtained from the superposition of relevant data for each delivered GK-shot. Single shot dosimetry calculations were based on the nominal dose rate at the center of each shot and corresponding relative dose profile data. TR-DRD were estimated neglecting 60Co source decay during the irradiation of each shot. A formalism including frequently used radiobiological tools that accounts for the effect of dose rate and incorporates fast and slow components of repair, was developed on the basis of the Biologically Effective Dose (BED). Patient and plan characteristics as well as dose and dose rate indexes incorporating the TR-DRD were introduced and their correlation with the corresponding radiobiological parameters was examined using the Spearman rank test. Results The nominal mean dose rate at focus (NMDR-F) presented a high correlation with the percentage of the total dose delivered with dose rates lower than 1 Gy/min, TD 1 Gy / min , ( r = - 0.837 and p = 5.32 E - 20 ) and the percentage of the PTV volume receiving dose rates lower than 1 Gy/min from all shots, V 1 Gy / min ( TR-DRD ) ( r = - 0.830 and p = 6.43 E - 20 ). A statistically significant correlation was also found between the number of iso-centers used per PTV volume (Unit Isocenter, UI) and the V 1 Gy / min ( TR-DRD ) ( r = 0.268 and p = 0.021 ) as well as the percentage of the PTV volume receiving dose values lower than 15 Gy, V 15 Gy ( r = 0.543 and p = 5.90 E - 07 ). The Equivalent Uniform BED (EUBED) was significantly correlated with the UI ( r = - 0.4318 and p = 0.0001 ), the UI/NMDR-F ( r = - 0.3955 and p = 0.0005 ), the V 1 Gy / min ( TR-DRD ) ( r = - 0.3155 and p = 0.0062 ) and the V 15 Gy ( r = - 0.569 and p = 1.25 E - 07 ). Conclusion The observed correlation between the TR-DRD based parameters and the EUBED suggests that the former should be taken into account at the planning stage of radiosurgery, either directly or indirectly via plan characteristics readily evaluated in every day clinical routine (NMDR-F, UI) that are correlated with TR-DRD based dose and dose rate parameters.

Microsurgery Results in Vestibular Schwannoma Patients; Retrospective Clinical Study

Microsurgery Results in Vestibular Schwannoma Patients; Retrospective Clinical Study

Stereotactic radiotherapy in three weekly fractions for the management of vestibular schwannomas

PurposeThis study evaluates the rates of tumor control, hearing preservation and cranial nerve toxicity with the use of CyberKnife stereotactic radiotherapy consisting of 2100 cGy to the 80% isodose line delivered in three weekly fractions to treat vestibular schwannomas. Materials and methodsRetrospective chart review of vestibular schwannoma patients treated with CyberKnife stereotactic radiotherapy or undergoing watchful waiting between 2006 and 2017 was performed. For inclusion, patients receiving CyberKnife stereotactic radiotherapy must have had pretreatment magnetic resonance imaging and audiography, and 2 follow-up magnetic resonance imaging and audiograms. Watchful waiting patients must have had a minimum of 2 magnetic resonance imaging and 2 audiograms. ResultsForty patients met inclusion criteria. Twenty-two underwent CyberKnife stereotactic radiotherapy. Eighteen remain in watchful waiting. Crude tumor control was 86.4% at mean radiographic follow-up of 52.3 months. Kaplan-Meier progression-free survival was 76.9% at 5 years. Kaplan-Meier survival from radiographic growth was 61.5% at 5 years. Kaplan-Meier hearing preservation was 17.5% at 5 years. All patients undergoing watchful waiting presenting with serviceable hearing maintained serviceable hearing. Serviceable hearing among CyberKnife stereotactic radiotherapy patients was 42.9% prior to treatment and 14.2% through mean follow-up of 53.7 months. One patient experienced trigeminal nerve toxicity 45 months after SRT. 95.5% of CyberKnife stereotactic radiotherapy patients were complication-free. ConclusionsOur fractionation regimen provides tumor control consistent with current literature. Hearing outcomes, however, should be discussed with patients prior to CyberKnife stereotactic radiotherapy.

The impact of MRI steady-state sequences as an additional assessment modality in vestibular schwannoma patients after LINAC stereotactic radiotherapy or radiosurgery.

Data concerning the clinical usefulness of steady-state sequences (SSS) for vestibular schwannomas (VS) after linear accelerator (LINAC) stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) are scarce. The aim of the study was to investigate whether SSS provide an additional useful follow-up (FU) tool to the established thin-layered T1 sequences with contrast enhancement. Pre- and post-treatment SSS were identified in 45consecutive VS patients (2012-2016) with astandardized FU protocol including SSS at 2-3months and 6months/yearly in our prospective database and were retrospectively re-evaluated. The SSS were used throughout for the segmentation of the cochlea and partly of the trigeminal nerve in the treatment planning. Data analysis included signal conversion in SSS and possible correlation with neuro-otological outcome and volumetric assessment after a certain time interval. The series included 42SRS and 3SRT patients (31female/14male; mean age 59.3years, range: 25-81years). AnSSS signal conversion was observed in 20tumors (44.4%) within amean time of 11months (range: 7-15months). Mean FU time was 26months (median of 4FU visits) and demonstrated tumor volume shrinkage in 29cases (64.4%) correlating with FU time (p = 0.07). The incidence rate of combined shrinkage and signal conversion (48.3%) compared to those without signal conversion (51.7%) did not differ significantly (p = 0.49). In case of an early signal conversion at the first FU, aweak statistical significance (p = 0.05) for ahigher shrinkage rate of VS with signal conversion was found. Side effects in cases with signal conversion (9/20, 45%) were more frequently than without signal conversion (6/25, 24%) without reaching statistical significance (p = 0.13). Our data confirmed the usefulness of SSS for anatomical segmentation of VS in LINAC-SRS/SRT treatment planning and add data supporting their potential as an adjunctive FU option in VS patients.

Toxicity of Gamma Knife Radiosurgery May Be Greater in Patients with Lower Cranial Nerve Schwannomas.

Objective Gamma Knife stereotactic radiosurgery (GK-SRS) is a preferred treatment option for tumors of the jugular foramen. We hypothesized that GK-SRS toxicity is higher for lower cranial nerve schwannomas than for glomus jugulare tumors despite anatomically similar locations. Methods We performed a retrospective review of all patients who received GK-SRS for glomus jugulare tumors and lower cranial nerve schwannomas at our institution between 2006 and 2014. Because of small sample sizes, Fisher's exact tests and logistic regression techniques were employed using SPSS. Result We identified 20 glomus jugulare tumors and 6 lower cranial nerve schwannoma patients with a median follow-up of 17 months. Median marginal dose was 16 Gy (range 13-18 Gy) and 12.5 Gy (range 12-14 Gy), respectively. All except one patient had tumor control at last follow-up visit. No worsening of pre-existing neurological deficits was observed. There were seven patients who developed any new neurological deficit after GK-SRS, four from the glomus group, and three from the schwannoma group (20 and 50% of each group, respectively). Only two of seven patients had permanent new neurological deficits. Both of them were in the schwannoma group. Univariate analysis showed that only a diagnosis of schwannoma had a greater risk of permanent new cranial nerve complication after GK-SRS compared with diagnosis of glomus jugulare ( p = 0.046). Conclusion Although the marginal dose for glomus jugulare is greater, our study suggests that the risk of a new permanent neurological deficit after GK-SRS was higher in the schwannoma group compared with the glomus group.

PV-0367: Relationship between labyrinth dose and dizziness in vestibular schwannoma patients treated with SRS

PV-0367: Relationship between labyrinth dose and dizziness in vestibular schwannoma patients treated with SRS

Reduced Purposeful Head Movements During Community Ambulation Following Unilateral Vestibular Loss

Background. Individuals with unilateral vestibular hypofunction (UVH) alter their movement and reduce mobility to try to stabilize their gaze and avoid symptoms of dizziness and vertigo. Objective. To determine if individuals with UVH 6 weeks after surgery demonstrate altered head and trunk kinematics during community ambulation. Methods. A total of 15 vestibular schwannoma patients with documented postoperative unilateral vestibular loss and 9 healthy controls with symmetrical vestibulo-ocular reflexes participated in this cross-sectional study. Head kinematics (head turn frequency, amplitude, and velocity) and head-trunk coordination during community ambulation were obtained from inertial measurement units for all head movements and within specific amplitudes of head movement. Results. Individuals with UVH made smaller (mean 26° [SD = 3°] vs 32° [SD = 6°]), fewer (mean 133 [SD = 59] vs 221 [SD = 64]), and slower (mean 75°/s [SD = 8°/s] vs 103°/s [SD = 23°/s]) head turns than healthy individuals (P < .05) but did not demonstrate significantly increased head-trunk coupling (mean 38% [SD = 18%] vs 31% [SD = 11%], P = .22). When small (≤45°) and large (>45°) head turns were considered separately, individuals with UVH demonstrated increased head-trunk coupling compared with healthy individuals for large head turns (mean 54% [SD = 23%] vs 33% [SD = 10%], P = .005). Conclusions. This study demonstrated that although walking at an adequate speed, individuals with UVH made fewer, smaller, and slower head movements symmetrically in both directions compared with healthy individuals and did not decouple their head movement relative to their trunk when required to make larger purposeful head turns during community ambulation.

Air-conducted and skull-tap cervical vestibular evoked myogenic potentials in determining nerve division involvement in vestibular schwannoma patients

Air-conducted and skull-tap cervical vestibular evoked myogenic potentials (AC-cVEMP and Tap-cVEMP) have been shown to be very promising tools in clinical practice. They are noninvasive, easy to obtain and - importantly - they require little time and the cost of the instruments is low. The aim of this study was to evaluate the usefulness of the combined use of ACand Tap-cVEMPs as a diagnostic tool for advanced assessment of vestibular schwannoma in determining tumor origin, and to investigate whether the results are helpful for a surgeon as an additional source of information about the tumor before surgery. ACand Tap-cVEMPs were acquired (with EMG-based biofeedback) from the sternocleidomastoid muscles (SCM) of 30 vestibular schwannoma patients just before surgery. The results were compared to the surgical information about nerve bundle involvement in the tumor and the size of the tumor obtained from magnetic resonance imaging (MRI). On the tumor side, abnormal corrected amplitude asymmetry ratios were detected in 73.33% of the patients, abnormalities in P1-latencies in 70% of the patients, and both in 90% of the patients. The cervical vestibular evoked myogenic potential (cVEMP) results indicated the affected nerve division to be the inferior in 23.33% of the patients, the superior in 20% of the patients, and both in 46.67% of the patients. No cVEMP abnormalities were found in 10% of cases. The combined results of both ACand Tap-cVEMP were significantly compatible with the surgical information about the tumor origin. The number of abnormalities was significantly correlated with the tumor size. The information provided by the combined application of ACand Tap-cVEMPs might be useful for a surgeon in presurgical planning, providing more detailed information about the tumor and the affected nerve division in the internal auditory canal. It is not a diagnostic replacement for MRI in vestibular schwannoma patients; however, in our opinion, ACand Tap-cVEMPs may serve as additional sources of information about the tumor before the surgery.

CyberKnife Radiosurgery of Skull-base Tumors: A UK Center Experience.

The study aim was to evaluate patient individualized Cyberknife® treatment for heterogeneous skull-base tumors. Patients treated between 2009 and 2013 at The Harley Street Clinic were studied. In total, 66 patients received 15–30 Gy in 1–5 fractions to a median planning target volume (PTV) of 6.4 cc, including patients with secondary, multiple, residual and recurrent tumors, and those with tumors of uncertain pathological type. Outcome analysis was pragmatically restricted to 35 patients who had single, primary tumors treated with curative intent, and sufficient diagnostic and outcome information. Sixteen vestibular schwannoma patients with median PTV 3.8 cc (range 0.81–19.6) received 18–25 Gy in 3–5 fractions: 81% showed no acute toxicity, 50% reported no late toxicity, 71% of symptoms were stable/improved and local control was 100% at 11.4 months median follow-up. Twelve meningioma patients with median PTV of 5.5 cc (range 0.68–22.3) received 17–30 Gy in 1–5 fractions: 83% experienced no acute toxicity, 33% reported no late toxicity, 88% of symptoms were stable/improved and local control was 100% at 22.1 months median follow-up. Seven patients with other tumor types with median PTV of 24.3 cc (range 7.6–100.5) received 15–28.5 Gy in 1–5 fractions: 57% experienced no acute toxicity, 57% reported no late toxicities, 66% of symptoms were stable and local control was 43% at 14.9 months median follow-up. When tumor types were considered together, smaller tumors (PTV < 6.4 cc) showed reduced acute toxicity (p = 0.01). Overall, smaller benign tumors showed low acute toxicity, excellent local control, and good symptom management: a focus on enhanced neurological preservation may refine outcomes. For other tumor types outcome was encouraging: a focus on optimal dose and fractionation scheduling may reduce toxicity and improve local control. Individual patient experiences are detailed where valuable lessons were gained for optimizing local control and minimizing toxicity.

Sensorineural hearing loss in patients with vestibular schwannoma relies on the presence of utricular hydrops, as diagnosed with heavily weighted T2 sequences

Purpose Due to the increased protein concentration in the perilymph liquid, FIESTA-C has recently been proposed to assess endolymphatic spaces without administration of contrast media in patients with vestibular schwannoma. The aim of this study was to assess whether vestibular endolymphatic space dilatation, as evaluated with 3D-FIESTA-C sequences, is related to the degree of hearing loss in patients with schwannoma. Materials and methods In this retrospective study (IRB 5995), we performed 3D-FIESTA-C sequences in 32 patients with schwannoma, as diagnosed on the basis of typical image findings. Two radiologists independently checked the visualization and evaluated the volume of the utricle and saccule. Pearson and Spearman tests were used to explore the correlation between the volume of the tumor, the volume of the vestibular endolymphatic space and the degree of hearing loss – as evaluated with the levels of pure-tone average (PTA) and speech recognition threshold (SRT). Results The endolymphatic space can be evaluated in 72% (23 out of 32 patients) of patients with schwannoma on non-contrast 3D-FIESTA-C sequences. The mean saccular, utricular and tumor volume were 3.17 mm3, 14.55 mm3 and 1.74 cm3 respectively. There was a significant correlation between the volume of the utricle and the degree of hearing loss as evaluated with the levels of PTA (p = 0.015) and SRT (p = 0.004). There was no significant correlation between the saccular and tumor volumes and the degree of hearing loss. Conclusion The volume of the utricle in schwannoma patients is related to the degree of hearing loss.