Diagnosis and management of intralabyrinthine schwannomas.

OBJECTIVES/HYPOTHESIS: Describe the symptoms, signs, radiographic findings, and treatment results for four patients with intralabyrinthine schwannoma beginning either primarily within the labyrinth or extending secondarily into the labyrinth from the internal auditory canal. STUDY DESIGN: Retrospective review. METHODS: Review of clinic records, operative records, imaging studies with follow-up telephone interview, and when possible, repeat examination. RESULTS: Four patients with intralabyrinthine schwannoma treated by the first author were identified. Episodic vertigo, indistinguishable from Meniere's disease, was present in all but one of the patients in this study. A progressive unilateral hearing loss was also found in all of the patients. Magnetic resonance imaging revealed tumor isolated to the vestibule in two patients with the cochlea primarily involved in the other two patients. Intracochlear tumor extending into the internal auditory canal had been missed on preoperative imaging in one patient and was found during a translabyrinthine vestibular nerve section. In another patient with an intracanalicular schwannoma, tumor extending into the basal turn of the cochlea was not removed during a translabyrinthine approach to the internal auditory canal. The tumor subsequently recurred, necessitating a transotic approach for removal. A transmastoid/translabyrinthine approach was used to successfully remove tumor in one patient. Another patient with good hearing and no vestibular symptoms at time of this writing is being followed with serial imaging studies. As expected, the three patients who underwent surgery have anacusis in the operated ear and are free of vertigo at follow-up intervals of 12, 26, and 65 months. CONCLUSIONS: Intralabyrinthine schwannomas are rare tumors with optimal treatment being determined by the symptoms, tumor location, and hearing. Findings of an intralabyrinthine schwannoma on magnetic resonance imaging may be easily overlooked and attributed to inflammatory changes.     

Combined surgical approach to intralabyrinthine schwannoma

IntroductionIntralabyrinthine schwannoma (ILS) is a tumor originating from the Schwann cells in the inner ear. Various surgical approaches can be used for the resection of ILS. The aim of this report is to describe a case involving a 60-year-old man who was treated successfully with a combined surgical approach.Case reportThe patient underwent a combined microscopic (transmastoid labyrinthectomy) and endoscopic procedure for surgical excision of ILS involving the vestibule and the lower half of the cochlear basal turn. The combined surgical technique enabled a complete removal of the ILS without removal of the unaffected cochlea as well as the external auditory canal. Besides additional exclusion of the middle ear, blind-sac closure of the external auditory canal and cavity obliteration were avoided. No postoperative complications were observed.DiscussionA combined microscopic and endoscopic approach to surgery enables removal of the ILS involving the vestibule and the lower half of the cochlear basal turn while helping to reduce surgical radicality.     

Inner ear extension of vestibular schwannomas

OBJECTIVE: Inner ear extension of vestibular schwannomas (VSs) is a rare finding but has important clinical implications. This report reviews the treatment options and presents the experience of the Gruppo Otologico, Piacenza, Italy, in this field. STUDY DESIGN: Case report and literature review. METHODS: Five cases of VSs with inner ear extension were surgically removed. In all of them, the cochlea was partially or completely invaded by the lesion. RESULTS: In 4 cases, the inner ear extension was preoperatively identified on magnetic resonance imaging, and the surgical removal was planned through a transotic approach. In the last case, the cochlear invasion was not detected preoperatively, and the lesion was removed during a second surgery performed to seal a cerebrospinal fluid fistula. CONCLUSIONS: VSs with inner ear extension should be distinguished from pure intralabyrinthine schwannomas because of differences in clinical significance. Cochlear involvement is more frequent than vestibular involvement and is often accompanied by a dead ear. Dead ear caused by small VSs should alert the surgeon to the possibility of a cochlear extension. The presence of an intracochlear involvement requires the adoption of an approach that allows control of the cochlear turns, and we found the transotic approach to be the most suitable. Undetected cochlear extensions that are left in place may grow with time.     

Neurinoma intralaberíntico: manejo,exéresis y restauración auditiva con implante coclear

Introduction and objectiveVestibular schwannoma is a benign tumour that originates in the eighth cranial nerve. It is termed intralabyrinthine schwannoma (ILS) when it develops in the inner ear, this being a rare origin. We present our experience in the management of three patients with ILS.Material and methodsThe results of tumour excision and cochlear implantation were evaluated in three patients with ILS: two intracochlear schwannomas (ICS) and one intravestibular schwannoma (IVS).ResultsPrior to surgery, all patients presented progressive sensorineural hearing loss and tinnitus. Complete tumour resection and cochlear implantation was possible in all patients, with favourable hearing rehabilitation.ConclusionsThe therapeutic approach will depend on tumour size, growth rate, degree of hearing loss and presence of vestibular symptoms. Cochlear implantation (CI) in patients with ILS is possible when the cochlear nerve is present and functional. CI in patients, whether or not preceded by tumour excision, is an option with good hearing results in selected patients.     

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

Purpose

This 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.

Ipsilateral and contralateral vestibular schwannomas in unilateral long-term deaf ears

In the past decade, we have encountered two patients with unilateral long-term deaf ear having vestibular schwannoma. One was on the deaf ear in a 53 years’ woman and the other was on the contralateral hearing ear in a 62 years’ woman. These two patients had total deafness on the right ear since childhood, associated with absent auditory brainstem response (ABR) and caloric responses, whereas normal ABR and caloric responses were shown on the left ear. Although similar physiological findings were disclosed on the deaf ears, MRI scan demonstrated vestibular schwannoma on the different side, that is, one in deaf ear and the other in hearing ear. For the former, absent ABR and caloric results indicate that the tumor originates from the superior vestibular nerve. In contrast with the latter, normal ABR and caloric responses, but absent vestibular-evoked myogenic potentials on the hearing ear imply that the tumor originates from the inferior vestibular nerve. The ipsilateral tumor on the deaf ear underwent intracranial surgical excision, followed by radiosurgery due to tumor recurrence 10 years later, while the contralateral one on the only hearing ear received radiosurgery only. Both patients were rather well, 3 years after last treatment.     

A cochlear schwannoma presenting with sudden hearing loss

A cochlear schwannoma is a rare tumor that arises from the cochlear nerve. Clinically, a cochlear schwannoma mimics the clinical features of sudden deafness or Meniere's disease. We report a case of cochlear schwannoma that presented with sudden hearing loss, which was diagnosed with gadolinium-enhanced magnetic resonance imaging and removed using a transotic approach.     

Conservative management of vestibular schwannomas: an effective strategy

Objectives: Stimulated by the availability of a larger sample of patients and a longer follow‐up period, we update our experience with conservative management of vestibular schwannomas. Study Design: Patients with intracanalicular and small/medium‐sized tumors have been followed prospectively at a tertiary referral center. Methods: One hundred twenty‐three patients affected by sporadic vestibular schwannoma were primarily observed by means of magnetic resonance imaging scans. In case of significant tumor growth (≥2 mm), patients were either surgically treated or submitted to radiotherapy, but, not rarely, they continued to follow the “wait‐and‐scan” policy. Tumor‐size changes over time were also evaluated with hearing function. Statistical analysis with predictive growth factors was performed. Results: Almost two thirds (64.5%) of the cases did not show tumor growth during the entire period of observation (mean follow‐up period, 4.8 yrs). Among growing tumors, 16 patients were surgically treated with no complications or facial nerve palsy. Less than half (45.5%) of the patients presented useful hearing (classes A and B of the American Academy of Otolaryngology–Head and Neck Surgery classification) at diagnosis, and 41 (73.2%) patients had preserved hearing during follow‐up independently from the tumor growth rate. Conclusions: Conservative management of vestibular schwannoma appears to be a safe procedure because most tumors do not grow and surgical outcomes are not affected by possible delays. In the great majority of cases, useful hearing is maintained over time. Because of the irregular behavior of the tumor, periodic neuroradiologic scans are mandatory to limit late surgical risks.     

Predictors of future growth of sporadic vestibular schwannomas obtained by history and radiologic assessment of the tumor

Management of a sporadic vestibular schwannoma (VS) is still a subject of controversy, mainly due to distinct and unpredictable growth patterns. To embark on an appropriate therapy it is necessary to dispose of a reliable prediction about tumor progression. This study aims to design a risk profile with predictors for VS growth. A total of 234 VS patients who were managed conservatively were included. Data concerning (duration of) symptoms and localization of VS were analyzed with Cox proportional hazards regression models. Predictors for growth are unsteadiness/vertigo, no sudden onset of hearing loss and short duration of hearing loss. High-risk patients have (1) VS with an extrameatal localization, short duration of hearing loss and at least one of the two other predictors (unsteadiness/vertigo or no sudden sensorineural hearing loss) or (2) VS with an intrameatal localization and all three other predictors. Low-risk patients have (1) VS with an extrameatal component and no other predictor or (2) VS with an intrameatal localization and at most one other predictor. High-risk patients have a risk of growth of 36.9% in the first year and 64.6% in the second year. For patients with a low risk this is 2.5 and 12.7%, respectively. Simple data gathered at the moment of diagnosis may provide useful information since they may lead to a risk profile for growth.     

Clinical experience with vestibular schwannomas: epidemiology, symptomatology, diagnosis, and surgical results

The Danish model for vestibular schwannoma (VS) surgery has been influenced by some historical otological events, taking its origin in the fact that the first attempt to remove CPA tumors was performed by an otologist in 1916. In approximately 50 years VS surgery was performed by neurosurgeons in a decentralized model. Highly specialized neuro- and otosurgeons have been included in our team since the early beginning of the centralized Danish model of VS surgery in 1976. Our surgical practice has always been performed on the basis of known and proven knowledge, but we spared no effort to search for innovative procedures. The present paper reflects the experience we have gained in two decades of VS surgery. Our studies on the incidence, symptomatology, diagnosis, expectancy and surgical results are presented. Received: 26 February 1997 / Accepted: 7 July 1997     

Electronystagmographic changes in patients with unilateral vestibular schwannomas in relation to tumor progression and central compensation

Vestibular function was studied in a group of 121 patients with unilateral vestibular schwannomas who were referred to University Hospital Utrecht between 1986 and 1996. Testing included the caloric test, torsion test, saccade test, smooth pursuit test and the registration of spontaneous nystagmus. Each patient’s symptoms were taken from a chart review. The size of the tumor was expressed as the maximum extrameatal diameter in the axial plane parallel to the petrous ridge as seen in magnetic resonance imaging or computed tomography. Large tumors were significantly more often accompanied by a more severe paresis on caloric testing, a smaller gain on torsion testing, spontaneous nystagmus, an abnormal saccade test and an abnormal smooth pursuit test. The presence of spontaneous nystagmus was significantly more frequently combined with an abnormal smooth pursuit and saccade test. There was a significant correlation between the slow component’s velocity of the spontaneous nystagmus and the size and progression of tumor. However, a specific relation between tumor size and central vestibular compensation could not be demonstrated. Received: 5 January 1998 / Accepted: 14 August 1998     

听神经瘤治疗策略

听神经瘤是一种比较常见的颅底良性肿瘤,常见症状有单侧感音性听力下降等。目前听神经瘤治疗方法包括定期随访观察、手术切除以及立体定向放射治疗。手术切除是听神经瘤的主要治疗方式,常用途径包括经乙状窦后（枕下）入路、经迷路入路及经颅中窝入路等。不同治疗方式、不同手术入路各有其适用范围及优缺点,因此,针对不同患者采取合适治疗方式十分必要。     

Long-term effects of cerebellar retraction in the microsurgical resection of vestibular schwannomas

OBJECTIVE: To determine the long-term effects, if any, of the greater cerebellar retraction that is required for retrosigmoid vestibular schwannoma versus resection as compared with the minimal, if any, cerebellar retraction required for translabyrinthine versus resection. STUDY DESIGN: Retrospective case control. METHODS: All patients who underwent retrosigmoid versus resection between 1988 to 2000 by one surgeon were identified. These patients were contacted and asked to complete the Dizziness Handicap Inventory (DHI). These patients were then matched to patients who underwent translabyrinthine versus resection according to age at surgery, age at time of study, sex, and size of tumor. Total DHI and subcategory DHI scores were compared using the Student t test. RESULTS: Thirty-three patients underwent the retrosigmoid approach, and 27 were contacted for completion of the survey, with a 81.3% response rate. Forty-six patients who underwent translabyrinthine versus resection were matched to the retrosigmoid group. Thirty-six were contacted and completed the survey for a 75% response rate. Twenty-seven patients that most closely matched the retrosigmoid group comprised the translabyrinthine group used for comparison. Minimal differences were seen between the two groups. Mean total DHI score for the retrosigmoid group was 17.6, which was not significantly different from the mean score of 16.8 seen in the translabyrinthine group (P =.888). When comparing small tumors (<1.5 cm), total DHI scores were not found to be significantly different (P =.859). We observed similar findings in those with intermediate-sized tumors (1.5-3 cm). CONCLUSION: The significantly greater cerebellar retraction that is necessary for retrosigmoid versus resection does not result in greater long-term balance and disability as compared with those patients who have undergone the translabyrinthine approach.     

Intralabyrinthine schwannomas: symptoms and managements

OBJECTIVE: To describe the characteristic presentations, radiologic findings and managements of the intralabyrinthine schwannomas. METHOD: Retrospective review of patient records, their managements, and review of the literature. RESULT: Four patients with a variety of otologic symptoms including hearing loss, vertigo, and tinnitus were found to have a schwannomas involving the labyrinth. In all cases, the inner ear lesions were preoperatively identified on magnetic resonance imaging, and the surgical removals were performed in all patients without serviceable hearing. The patients experienced improvement in their vertigo and tinnitus after surgery. Two patients were implanted the Bone-Anchored Hearing Aid (BAHA) to reconstruct the pseudo-stereophonic hearing. CONCLUSION: Intralabyrinthine schwannomas are the rare tumours in the otology. The tumour can be removed by surgical approach, but we do not propose surgical excision for the patients with serviceable hearing. BAHA can give patients a post-operative monaural pseudo-stereophonic hearing.