Small Vestibular Schwannomas Research Articles

Hearing preservation and growth of small vestibular schwannomas: preliminary outcomes from patients under observation

Objective: Conservative management in sporadic vestibular schwannomas (VS) represents a valid treatment option, however, tumour growth and hearing decay during observation are still a matter of controversy and shift to alternative therapies. The present study aims at evaluating patients diagnosed with VS submitted to a wait and scan protocol of treatment.Study design: Case series review from a tertiary referral centre. Data collected from an in-house prospectively-maintained database of 108 patients with sporadic small VS, managed with primary observation, were evaluated. Inclusion criteria were tumour diameter less than 10 mm in the cerebello-pontine angle. At serial follow-up evaluations, objective measures of hearing status and tumour growth through magnetic resonance imaging were conducted. Hearing status was stratified according to the Tokyo Consensus Meeting Guidelines. Tumour growth and hearing function represented the main endpoints and were analysed according to tumour site at diagnosis.Results: Eighty-one patients were included in the study. During observation with a mean follow-up time of 27 months, 29.6% of the patients demonstrated tumour growth, with extrameatal lesions growing faster than intrameatal tumours (p = .049). Decay of good hearing was observed in 32.5% of patients, with a higher frequency of hearing instability revealed in the intrameatal group of VS (p = .004). Conservative treatment was maintained in 75.3% of cases. In 18% of cases, patients underwent surgical VS removal, while only 6.2% of patients favoured radiotherapy.Conclusions: Conservative treatment led to low rates of tumour growth after a mean 27 months observation. The cases with good hearing at diagnosis evidenced hearing deterioration in 33.3% of patients. Wait and scan outcomes need to be evaluated in comparison with other active treatments in terms of hearing and growth and further studies are required in this sense.

Fractionated Stereotactic Radiation Therapy for Large Vestibular Schwannomas

Fractionated stereotactic radiotherapy (FSRT) is a well-established and effective treatment for vestibular schwannomas (VS). For larger VSs with brainstem compression, debulking surgery is often performed prior to radiation to reduce treatment volume and to decrease potential radiation damage to the brainstem and cranial nerves V and VII. The goal of this study was to retrospectively evaluate the clinical outcomes of patients with large VSs treated with FSRT at our institution. 60 patients were identified who had VSs treated with FSRT between 2009 and 2016. All patients were treated on a Novalis TX linear accelerator platform with a dose of 25 Gy in 5 fractions. Patients were categorized by Koos stage into small VS group (Koos stage 1 or 2) and large VS group (Koos stage 3 or 4). Outcomes of tumor control (freedom from radiographic progression), degree of trigeminal nerve dysfunction, degree of facial nerve dysfunction (using the House-Brackmann scale), and brainstem toxicity (radiographic necrosis) were assessed prior to treatment and at the most recent follow-up. The dose of radiation to the VS, cranial nerves, and brainstem (Dmax, D0.5cc, and V23) were evaluated in order to identify correlated late toxicity. The number of patients experiencing symptomatic pseudoprogression at any point post treatment was also recorded for each group. Clinical and radiographic data was available for 59 of the patients, and median follow-up was 33.5 months for the small VS group (range 5 – 76 months) and 15 months for the large VS group (range 2 – 49 months). The median treated volume for the small VS group was 0.9 cc (range 0.1 – 3.4 cc) and 5.2 cc for the large VS group (range 1.4 – 22.6 cc). The median brainstem Dmax was 16.5 Gy for the small VS group (range 1.1 – 28.4 Gy) and 26.1 Gy for the large VS group (range 21.7 – 30.4 Gy). The median D0.5cc was 4.75 Gy for the small VS group (range 0 – 21.7 Gy) and 20.5 Gy for the large VS group (range 9 – 23.8 Gy). The median V23 was 0.18 cc for the small VS group (range 0 – 0.33 cc) and 0.18 cc for the large group (0 – 0.62 cc). Tumor control was 100% in both groups, and there was no evidence of brainstem necrosis in either group. No patients experienced progression of trigeminal symptoms. Freedom from new facial neuropathy was 97.6% in the small VS group vs. 100% in the large VS group (p=0.99). Rates of pseudoprogression were 4.8% in the small VS group vs. 11.8% in the large group (p=0.13). Debulking surgery was performed in 2 of 42 patients in the small VS group and in 10 of 18 patients in the large VS group and was not found to affect any of these clinical outcomes. Patients with large VSs or with brainstem compression did not experience worse rates of tumor control, brainstem necrosis, pseudoprogression, or neuropathy compared to those with small VSs. Outcomes were similar for those treated with or without surgery, suggesting that FSR alone is a reasonable treatment option for patients with large VSs compressing the brainstem.

Translabyrinthine microsurgical resection of small vestibular schwannomas.

OBJECTIVE Translabyrinthine resection is one of a number of treatment options available to patients with vestibular schwannomas. Though this procedure is hearing destructive, the authors have noted excellent clinical outcomes for patients with small tumors. The authors review their experience at a tertiary acoustic neuroma referral center in using the translabyrinthine approach to resect small vestibular schwannomas. All operations were performed by a surgical team consisting of a single neurosurgeon and 1 of 7 neurotologists. METHODS Data from a prospectively maintained clinical database were extracted and reviewed. Consecutive patients with a preoperative diagnosis of vestibular schwannoma that had less than 1 cm of extension into the cerebellopontine angle, operated on between 2008 and 2013, were included. Patents with neurofibromatosis Type 2, previous treatment, or preexisting facial weakness were excluded. In total, 107 patients were identified, 74.7% of whom had poor hearing preoperatively. RESULTS Pathologically, 6.5% of patients were found to have a tumor other than vestibular schwannoma. Excluding two malignancies, the tumor control rates were 98.7%, as defined by absence of radiographic disease, and 99.0%, as defined by no need for additional treatment. Facial nerve outcome was normal (House-Brackmann Grade I) in 97.2% of patients and good (House-Brackmann Grade I-II) in 99.1%. Complications were cerebrospinal fluid leak (4.7%) and sigmoid sinus thrombosis (0.9%), none of which led to long-term sequelae. CONCLUSIONS Translabyrinthine resection of small vestibular schwannomas provides excellent results in terms of complication avoidance, tumor control, and facial nerve outcomes. This is a hearing-destructive operation that is advocated for selected patients.

Middle fossa approach for resection of vestibular schwannoma.

Surgical approaches for removal of vestibular schwannoma are done through retrosigmoid, translabyrinthine, or middle fossa approaches, depending on the tumor size, preoperative hearing status, surgical team experience, and patient preference. The middle fossa approach (MFA) for the vestibular schwannoma (VS) route preserves hearing and can be done with minimal morbidity and mortality. The authors discuss the surgical anatomy of the middle fossa, internal auditory canal localization techniques, MFA indications and the procedure for VS removal, and outcome. Unlike otolaryngologists, who use the MFA to treat various pathological processes that involve the inner or middle ear, many neurosurgeons are unfamiliar with the MFA. Nevertheless, learning the technical nuances of the MFA adds to the neurosurgeon's armamentarium, especially for treatment of small intracanalicular VSs in young patients who wish to preserve hearing.

Auditory adaptation testing as a tool for investigating tinnitus origin: two patients with vestibular schwannoma

Objective: To enhance the understanding of tinnitus origin by disseminating two case studies of vestibular schwannoma (VS) involving behavioural auditory adaptation testing (AAT). Design: Retrospective case study. Study sample: Two adults who presented with unilateral, non-pulsatile subjective tinnitus and bilateral normal-hearing sensitivity. At the initial evaluation, the otolaryngologic and audiologic findings were unremarkable, bilaterally. Upon retest, years later, VS was identified. Results: At retest, the tinnitus disappeared in one patient and was slightly attenuated in the other patient. In the former, the results of AAT were positive for left retrocochlear pathology; in the latter, the results were negative for the left ear although a moderate degree of auditory adaptation was present despite bilateral normal-hearing sensitivity. Imaging revealed a small VS in both patients, confirmed surgically. Conclusion: Behavioural AAT in patients with tinnitus furnishes a useful tool for exploring tinnitus origin. Decrease or disappearance of tinnitus in patients with auditory adaptation suggests that the tinnitus generator is the cochlea or the cochlear nerve adjacent to the cochlea. Patients with unilateral tinnitus and bilateral, symmetric, normal-hearing thresholds, absent other audiovestibular symptoms, should be routinely monitored through otolaryngologic and audiologic re-evaluations. Tinnitus decrease or disappearance may constitute a red flag for retrocochlear pathology.

Radiosurgery and fractionated stereotactic radiotherapy of vestibular schwannoma

Management of vestibular schwannoma (VS) should always be interdisciplinary and results better than the natural course. Particularly in small VS, either microsurgical resection or radiosurgery (RS) can be employed. RS is aspecial method (initially only possible stereotactically) for delivering high-precision radiation from many directions to the target point (the isocenter) in asingle high dose. With the development of three different systems-Gamma Knife (Elekta, Stockholm, Sweden), special linear accelerators, and CyberKnife (Accuray, Sunnyvale, CA, USA)-the options were extended to 1-5fractions for RS and multisession RS (msRS), and to up to 6weeks of conventional fractionation as stereotactic radiotherapy (SRT). Whereas RS uses high ablative single doses, SRT is based on the well-known radiobiological effects of multiple fractions comprising lower single doses up to arequired much higher total dose. Evaluation showed that RS and SRT achieve similarly high rates of tumor control of around 90% and low rates of side effects (1-7%). Therefore, SRT is unnecessary for small but clearly progressing VS, which has made RS avery comfortable, effective treatment option. In addition to SRT, larger VS can be treated comparably effectively with CyberKnife-based msRS. Since modern MRI frequently discovers small VS as "incidental findings", the initial biding strategy (wait and scan) is of particular importance. Only with increasing symptoms and detectable tumor growth is the treatment indication established, at which time the decision for surgery and RS/SRT should be taken interdisciplinary under consideration of the patient's wishes.

Early acoustic evoked potentials in patients with "small" vestibular schwannomas

The prognostic potential of click-evoked early acoustic evoked potentials (EAEP) for vestibular schwannoma (VS) diagnostics is considered insufficient for tumors small than approximately <1.5cm in diameter. However, up until now, the derivations at higher sound pressure levels have mainly been used for EAEP evaluation. The aim of this study was to examine whether registered EAEP are more sensitive to pathological changes at low sound pressure levels and with smaller tumors. Comparative examinations (pair-matched) were conducted with 34patients. An appropriate patient with an identical hearing level threshold - either apurely cochlear hearing deficiency or anormal hearing level - was matched to each tumor patient. EAEP were registered at 80, 60,and 40dBHL. The characteristic parameters where assessed visually and evaluated statistically, both in respect to patient groups and in bilateral comparisons. Furthermore, the relationship between the level-dependent waveV latency differences in bilateral comparison and tumor size were evaluated. Low-level cochlear hearing deficiencies did not cause achange in waveV latency, such that the pathological side differences at 40dBHL in patients with VS can be considered a"purely" retrocochlear hearing deficiency. The sensitivity of EAEP registered at 40dBHL decreases only with tumors under about <5mm in diameter. Combining the values of waveV latency and interaural waveV latency difference effectively reduces false-positive findings at 40dBHL to zero. Beyond the suprathreshold derivations, potential registrations at 40dBHL can also be diagnostically useful to differentiate cochlear from retrocochlear lesions. In the case of small VS and good hearing levels, these registrations may also be used for intraoperative monitoring to allow better evaluation of level-dependent changes in the auditory nerve.

ACTA OTORHINOLARYNGOLOGICA ITALICA

SUMMARYThe management of sporadic vestibular schwannoma (VS) has evolved in the last decades. The aim of this study was to analyse the evolution in surgical outcomes of VSs operated by a neurotological team between 1990 and 2006 by different approaches. A monocentric retrospective review of medical charts of 1006 patients was performed. In order to assess eventual changes and progress, the 17-years period was divided in three periods, each one comprehending 268 VS (1990-1996), 299 VS (1997-2001), and 439 VS (2002-2006). Mean follow-up was 5.9 ± 2.4 years. Overall, complete VS removal was achieved in 99.4% of cases. Mortality rate was 0.3%, meningitis and CSF leaks were observed in 1.2 % and 9 % of the cases, respectively. CSF leakage decreased from 11.6% to 7.1% between the first and last period (p < 0.01) as well as revision surgery from 3.4 % to 0.9 % (p < 0.05). Facial nerve was anatomically preserved in 97.7% of cases. At one year, a good facial nerve function was observed in 85.1% of patients (grade I and II of House-Brackmann grading scale), which ranged between the first and last period from 78.4% to 87.6% (p <0.05). At one year, hearing preservation was obtained in 61.6% of patients, which increased from the first period to the last one from 50.9% to 69.0% (p < 0.05) (class A+B+C from the AAO-HNS classification). Useful hearing (class A+B) was observed in 33.5% of cases overall, with 21.8% and 42% in the first and last period, respectively (p < 0.01). Surgical outcomes of sporadic vestibular schwannoma have improved concerning facial nerve function outcomes, hearing preservation and cerebrospinal fluid (CSF) leaks, mainly due to the neuro-otological team's experience. Functional results after complete microsurgical removal of large VS depend on experience gained on small VS removal.

Impacts of small vestibular schwannoma on community ambulation, postural, and ocular control

To investigate balance, community mobility, gaze instability, and dizziness handicap and assess falls risk in people who are conservatively managed with small vestibular schwannoma (VS). Cross-sectional study with controls. The study involved 18 people (mean age 58.7 ± 12.2 years) diagnosed with VS (<12 mm) and 22 age-matched controls (mean age 56.9 ± 8.0 years). Measures included standing on firm and foam surfaces with feet apart, then together with eyes open and closed, Timed Up and Go (TUG) test and dual TUG test, Dynamic Gait Index, 6-Minute Walk Test, Halmagyi Impulse Test, Dynamic Visual Acuity Test, and the Dizziness Handicap Inventory. The clinical group failed more trials standing feet together on foam with eyes closed (P < .05); had inferior mobility and walked more slowly with divided attention (P < .05); had more difficulty walking with head movement, negotiating obstacles, and using stairs (P < .01); and walked shorter distances (P < .001) than controls. Reduced gaze stability (P < .01) and higher total (P = .007) and subcategory dizziness handicap scores (P < .05) were revealed compared to age-matched controls. Although outcomes for the clinical group are inferior to the control group across all measures and the dizziness impact is higher, the results fall in the low-risk category for falls. Preliminary data (level 4 evidence) support using a suite of clinical measures to monitor people with VS during conservative management. 4 Laryngoscope, 127:1147-1152, 2017.

Optimal outcomes for hearing preservation in the management of small vestibular schwannomas.

To undertake a systematic review of the role of microsurgery, in relation to observation and stereotactic radiation, in the management of small vestibular schwannomas with serviceable hearing. The Medline database was searched for publications that included the terms 'vestibular schwannoma' and/or 'acoustic neuroma', occurring in conjunction with 'hearing'. Articles were manually screened to identify those concerning vestibular schwannomas under 1.5 cm in greatest dimension. Thereafter, only publications discussing both pre-operative and post-operative hearing were considered. Twenty-six papers were identified. Observation is an acceptable strategy for small tumours with slow growth where hearing preservation is not a consideration. In contrast, microsurgery, including the middle fossa approach, may provide excellent hearing outcomes, particularly when a small tumour has begun to cause hearing loss. Immediate post-operative hearing usually predicts long-term hearing. Recent data on stereotactic radiation suggest long-term deterioration of hearing following definitive therapy. In patients under the age of 65 years with small vestibular schwannomas, microsurgery via the middle fossa approach offers durable preservation of hearing.

Exclusive endoscopic transcanal transpromontorial approach: a new perspective for internal auditory canal vestibular schwannoma treatment.

OBJECTIVE The aim of this study was to describe the first case series in which an exclusive endoscopic transcanal transpromontorial approach (EETTA) was used to treat small vestibular schwannomas (VSs) and meningiomas of the internal auditory canal (IAC). METHODS The authors performed a retrospective review of patients who had undergone surgery using an EETTA to the IAC at 2 university tertiary care referral centers during the period from November 2011 to January 2015. RESULTS Ten patients underwent surgery via an EETTA for the treatment of VS in the IAC at the University Hospital of Modena or the University Hospital of Verona. The patients had Koos Grade I or II tumors and American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) Class D hearing status preoperatively. Gross-total resection was achieved in all patients. No major complications such as cerebrospinal fluid leakage or hemorrhage were reported. In 7 of 10 (70%) patients, facial nerve function was normal immediately after surgery (Rough Grading System [RGS] Grade I). Two patients presented with a transitory facial palsy immediately after surgery (RGS Grade II-III) but experienced complete recovery during the follow-up period. The mean follow-up was 10 months. CONCLUSIONS The EETTA proved to be successful for the removal of VS or meningioma involving the cochlea, fundus, and IAC, with possible lower complication rates and less invasive procedures than those for traditional microscopic approaches. The potential for the extensive and routine use of this approach in lateral and posterior skull base surgery will depend on the development of technology and surgical refinements and on the diffusion of skull base endoscopic skills among the otolaryngological and neurosurgical communities.

Safety and Efficacy of Gamma Knife Radiosurgery for the Management of Koos Grade 4 Vestibular Schwannomas.

Gamma Knife radiosurgery (GKRS) is commonly used in treating small vestibular schwannomas; however, its use for larger vestibular schwannomas is still controversial. To assess the long-term safety and efficacy of treating eligible Koos grade 4 vestibular schwannomas with GKRS. We conducted a single-center, retrospective evaluation of patient undergoing GKRS for Koos grade 4 vestibular schwannomas. We evaluated clinical, imaging, and treatment characteristics and assessed treatment outcome. Inclusion criteria were tumor size of ≥4 cm and follow-up of at least 6 months. Patients with neurofibromatosis type 2 were excluded. Primary outcomes measured were tumor control rate, hearing and facial function preservation rate, and complications. All possible factors were analyzed to assess clinical significance. Sixty-eight patients met inclusion criteria. Median follow-up was 47 months (range, 6-125 months). Baseline hearing was serviceable in 60%. Median tumor volume at radiosurgery was 7.4 cm (range, 4-19 cm). The median marginal dose used was 12 Gy at the 50% isodose line. Actuarial tumor control rates were 95% and 92% at 2 and 10 years, respectively. Actuarial serviceable hearing preservation rates were 89% and 49% at 2 and 5 years, respectively. Facial nerve preservation was 100%. Clinical complications included balance disturbance (11%), facial pain (10%), facial numbness (5%), and tinnitus (10%). Most complications were mild and transient. Hydrocephalus occurred in 3 patients, requiring ventriculoperitoneal shunt insertion. Larger tumor size was significantly associated with persisting symptoms post-treatment. Patients with Koos grade 4 vestibular schwannomas and minimal symptoms can be treated safely and effectively with GKRS.

Small Vestibular Schwannomas: Does Surgery Remain a Viable Treatment Option?

Background Surgery for small vestibular schwannomas (Koos grade I and II) has been increasingly rejected as the optimal primary treatment, instead favoring radiosurgery and observation that offer lower morbidity and potentially equal efficacy. Our study assesses the outcomes of contemporary surgical strategies including tumor control, functional preservation, and implications of pathologic findings. Design Retrospective review. Setting/Participants Eighty consecutive patients (45 women, 35 men; mean: 47 years of age). Main Outcomes Measures Approaches included retrosigmoid approach (52%), translabyrinthine (40%), and middle fossa (8%). Operated on by the same surgical team, we analyzed presentation, radiographic imaging, surgical data, and outcomes. Results At last follow-up (mean: 34 months), 95% had good facial nerve function (House-Brackmann grade I or II); 36% who presented with serviceable hearing retained it; and 93% who presented with vestibular dysfunction reported resolution. Pathology identified two grade I meningiomas. Conclusions As one of the largest contemporary surgical series of small vestibular schwannomas, we discuss some nuances to help refine treatment algorithms. Although observation and radiosurgery have established roles, our results reinforce microsurgery as a viable, safe option for a subgroup of patients.

Clinical and Radiographic Factors Predicting Hearing Preservation Rates in Large Vestibular Schwannomas.

Objectives Postoperative hearing preservation rates for patients with large vestibular schwannomas range from 0 to 43%. The clinical and radiographic factors predicting hearing preservation in smaller vestibular schwannomas are well described; however, their importance in larger tumors is unclear. We investigated factors predicting hearing preservation in large vestibular schwannomas. Design Retrospective review. Setting Quaternary care academic center. Participants A total of 85 patients with unilateral vestibular schwannomas > 3 cm underwent retrosigmoid resections. Main Outcomes Measures Preoperative and postoperative serviceable hearing rates. Methods Clinical and radiographic data including preoperative and postoperative audiograms, preoperative symptoms, magnetic resonance imaging features, and postoperative facial weakness were analyzed. Results Hearing was preserved in 41% of patients (17 of 42) with preoperative serviceable hearing. Hypertension and diabetes increased the likelihood of preoperative hearing loss. Preoperative tinnitus predicted a lower likelihood of hearing preservation. No radiographic factors predicted hearing preservation; however, larger tumor size, smaller fourth ventricular width, and the presence of a cerebrospinal fluid cleft surrounding the tumor predicted postoperative facial weakness. Conclusion Systemic comorbidities may influence hearing loss preoperatively in patients with large vestibular schwannomas. The absence of tinnitus may reflect hearing reserve and propensity for hearing preservation. Preoperative radiographic features did not predict hearing preservation despite some associations with postoperative facial weakness.

Discrimination of Hearing Disorder by Means of CLS and OAE in Vestibular Schwannoma

Currently a sensitive early diagnosis of small vestibular schwannoma is only possible by using magnetic resonance imaging (MRI). The main objective was a differentiation of the cochlear and retrocochlear component of small vestibular schwannoma with the help of categorial loudness scaling (CLS) and the growth function of otoacoustic emissions (DPOAE I/O-functions). 34 patients (gr. 1: 17 patients with vestibular schwannoma ≤15 mm, gr. 2: 17 matched patients with an inner ear hearing disorder) were examined. Besides audiological standard procedures they also underwent CLS according to the Würzburger auditory field and a generation of DPOAE I/O-functions was conducted on the probands. The gradients of the loudness growth function as part of the CLS and the DPOAE I/O-functions showed with few exceptions [500 Hz at 0-10 dB HL during CLS (p=0,040)] no significant differences between the groups (all p>0.05). A recruitment verification with the help of CLS was possible for tumors starting at a size of 5.45,mm at 3,000 and 4,000 Hz, respectively for tumors exceeding the size of 6.85 mm at 6,000 Hz with 100% sensitivity but only low specificity. A differentiation between a vestibular schwannoma and a mere cochlear hearing disorder with only the help of CLS and DPOAE I/O-functions is not possible. The results corroborate the thesis of an additional cochlear component even in small vestibular schwannoma. The implementation of CLS to determine cochlear deficits linked to vestibular schwannoma seems to be medically sensible if the tumor size exceeds 5 mm. According to the diagnostic method used to determine vestibular schwannoma MRI remains the first choice procedure.

Treatment decision-making for sporadic small vestibular schwannoma in a pediatric patient: A case report and literature review.

The current study reports the case of a 15-year-old male who presented with hearing loss due to a small left-sided vestibular schwannoma (VS) not associated with neurofibromatosis type 2 (NF2), which had been apparent for six months. Magnetic resonance imaging with gadolinium diethylenetriamine penta-acetic acid revealed a mass, 10 mm in diameter, located in the left inner auditory canal. The patient had no family history of NF2 and gene mutation analysis showed no signs of the condition. Small sporadic or non-NF2 VS is extremely rare and the treatment decision-making process is complicated in children when considering the implications for the impairment of childhood development and lifelong disability. Following careful consideration, the patient in the present study underwent treatment with stereotactic radiosurgery. The five-year post-operative follow-up examination showed tumor stability without additional neurological deficits and at the time of writing the patient was alive and well.

The video head impulse test

Conclusion: Additional research is needed to validate the importance of the video head impulse tests (vHIT), but it provides an important contribution to the evaluation of anterior and posterior semicircular canal disorders. Objectives: To share observations of the vHIT test in clinical neurotology and to discuss the significance of the study findings. Methods: This study comprised 200 patients with a clinical history of vestibular disturbances who were submitted to a vHIT including all six semicircular canals. Results: Abnormal responses of the anterior and posterior canals were found in several patients, either alone or combined with altered responses in the lateral canals. A unilateral hypoactive response of a posterior canal was found in a patient with a small vestibular schwannoma.

Post-surgical vestibular schwannoma remnant tumors: What to do?

BackgroundVestibular schwannomas (VS) are benign tumors of the vestibular nerve's myelin sheath. The current trend in VS surgery is to preserve at the facial function, even if it means leaving a small vestibular schwannoma tumor remnant (VSTR) after the surgery. There is no defined therapeutic management VSTR. The aim of this study was to assess the evolution of the VSTR to define the best therapeutic management and identify predictive factors of VSTR progression. MethodsAmong the 256 patients treated surgically for VS in the Department of Neurosurgery at Angers University Hospital, 33 patients with a post-surgical VSTR were included in this retrospective study. For all surgical patients, the data collected were age at diagnosis, the Koos classification, the surgical access, the existence of a type 2 neurofibromatosis (NF2), the TR location and size on control MRI-scans. Patients had a bi-annual follow-up with clinical status and VSTR size assessment with MRI-scan. Survival analyzes were performed to determine the time and rate of VSTR progression, and identify factors of progression. ResultsThe mean follow-up of the population was 51 months. All VS remnant progression occurred between 38 and 58 months after surgery. In non-NF2 patients with first follow-up MRI-scan three months after surgery, 43% presented a spontaneous regression, 50% a stability and 7% a progression of the VSTR. In the same population with the 1-year MR-scan after surgery as baseline, 25% presented a spontaneous regression, 62.5% a stability and 12.5% a VSTR progression. These data are consistent with the data reported in the literature. The post-operative facial function impairment and an initial remnant ≥ 1.5cm3 were found to be significant risk factors of VS remnant progression in non-NF2 population in univariate analysis (P=0.048 and 0.031) but not in multivariate analysis. ConclusionIn our experience, the best therapeutic management of the post-surgical VSTP in non-NF2 patients with no risk factor of progression is a simple clinical radiological follow-up otherwise complementary radiosurgery should be considered.

The Factors Associated With Tumor Stability Observed With Conservative Management of Intracanalicular Vestibular Schwannoma

Periodic observation with imaging is an acceptable option for patients with small vestibular schwannomas (VSs). The objective of this study was to evaluate the outcome of conservative management of intracanalicular VSs (ICVSs). We reviewed 31 patients who were followed up for more than 1 year among patients diagnosed as having VS limited to the internal auditory canal. The median follow-up period was 31 months (range, 12-84 mo). We analyzed the patients' clinical features, clinical courses, and audiologic changes. The most frequent initial presenting symptom in patients with ICVS was hearing loss, and one-half of the patients (8 of 16) had a history of sudden hearing loss. Seven patients (22.5%) showed tumor growth during the follow-up period. When we considered the initial tumor size in ICVS, the patients larger in size than the median showed a significantly higher rate of tumor growth. In terms of the initial hearing levels of ICVS according to the Consensus Meeting Guidelines, five patients were classified as Class A (normal hearing) and six patients were classified as Class B. Only one patient among patients with useful hearing (Classes A and B) showed tumor growth. The follow-up hearing levels of all Class A patients were preserved; however, all Class B patients deteriorated to Class C. Patients with ICVS showed favorable results with conservative management. Among them, patients with small tumors and normal hearing showed a good prognosis.

Small Vestibular Schwannomas Presenting with Facial Nerve Palsy

To describe the surgical management and convalescence of two patients presenting with severe facial nerve weakness associated with small intracanalicular vestibular schwannomas (VS). Retrospective review. Two adult female patients presenting with audiovestibular symptoms and subacute facial nerve paralysis (House-Brackmann Grade IV and V). In both cases, post-contrast T1-weighted magnetic resonance imaging revealed an enhancing lesion within the internal auditory canal without lateral extension beyond the fundus. Translabyrinthine exploration demonstrated vestibular nerve origin of tumor, extrinsic to the facial nerve, and frozen section pathology confirmed schwannoma. Gross total tumor resection with VIIth cranial nerve preservation and decompression of the labyrinthine segment of the facial nerve was performed. Both patients recovered full motor function between 6 and 8 months after surgery. Although rare, small VS may cause severe facial neuropathy, mimicking the presentation of facial nerve schwannomas and other less common pathologies. In the absence of labyrinthine extension on MRI, surgical exploration is the only reliable means of establishing a diagnosis. In the case of confirmed VS, early gross total resection with facial nerve preservation and labyrinthine segment decompression may afford full motor recovery-an outcome that cannot be achieved with facial nerve grafting.