Inner ear extension of vestibular schwannomas

The Feasibility of a Modified Exclusive Endoscopic Transcanal Transpromontorial Approach for Vestibular Schwannomas

Objective  We evaluated the feasibility of an exclusive endoscopic transcanal transpromontorial approach (EETTA) for the treatment of small vestibular schwannomas (VSs) limited to the internal auditory canal (IAC), and introduced a modification without external auditory canal closure.

Methods  Between June 2016 and June 2017, seven patients with VS underwent surgery using a modified EETTA. Treatment outcomes, including efficacy of tumor resection, preservation of function, operation time, and quality of life (QOL), were evaluated.

Results  The patients preoperatively exhibited Koos Grade I/II tumors and severe-to-profound hearing loss. Gross total resection was accomplished in all cases. There were no major complications, and all patients exhibited normal facial nerve function immediately after surgery. The mean follow-up period was 12.9 months. The operation time (average 196.3 ± 64.9 minutes) and hospitalization period (average 7.4 ± 1.0 days) were favorable. Short Form-36 scores for QOL showed unremarkable results compared with previous reports.

Conclusions  The modified EETTA was effective in the removal of VSs in the IAC. It can be an alternative surgical option for small VSs.

[Surgical indications and complications management in vestibular schwannoma]

BACKGROUND

Recent surgical treatment concepts for patients with vestibular schwannoma (VS) require an interdisciplinary approach as well as recognition and mastering of complications.

OBJECTIVE

This paper provides an overview of indications, as well as possible options for function preservation and management of complications in the surgical resection of these tumors.

METHODS

Up-to-date treatment concepts and surgical indications were differentiated according to size and extent of tumors. The frequency of important complications was extracted from the literature. Technical options to avoid and correct complications were compiled from personal experience and review of the literature.

RESULTS

Complications unrelated to cranial nerves are not infrequent, particularly in older patients. Small and medium-sized tumors that do not reach the fundus and cochlear fossa can be completely removed with good chances of hearing preservation. As long as these tumors do not grow, patients benefit from observation. Large tumors are overrepresented in surgical series compared to their prevalence. Postoperative facial nerve function correlates to tumor volume. Hearing preservation in these tumors is rare. Intraoperative electrophysiological techniques are valuable for attempted preservation of cranial nerve function. Persistent facial palsies can be remedied by dynamic and static interventions for facial rehabilitation.

CONCLUSION

Mortality and morbidity associated with surgical treatment of VS are very acceptable. Surgical concepts should be custom-tailored to the individual patient in order to ensure high quality of life.

Acoustic schwannoma with intracochlear extension and primary intracochlear schwannoma: removal through translabyrinthine approach with facial bridge cochleostomy and transcanal approach

Intracochlear schwannomas can occur either as an extension of a larger tumor from the internal auditory canal, or as a solitary labyrinthine tumor. They are currently removed via a translabyrinthine approach extended to the basal turn, adding a transotic approach for tumors lying beyond the basal turn. Facial bridge cochleostomy may be associated with the translabyrinthine approach to enable the whole cochlea to be approached without sacrificing the external auditory canal and tympanum. We describe seven cases, five of which underwent cochlear schwannoma resection with facial bridge cochleostomy, one case with the same procedure for a suspect tumor and one, previously subjected to radical tympanomastoidectomy, who underwent schwannoma resection via a transotic approach. Facial bridge cochleostomy involved removing the bone between the labyrinthine and tympanic portions of the fallopian canal, and exposing the cochlea from the basal to the apical turn. Patients' recovery was uneventful, and long-term magnetic resonance imaging showed no residual tumor. Facial bridge cochleostomy can be a flexible extension of the translabyrinthine approach for tumors extending from the internal auditory canal to the cochlea. The transcanal approach is suitable for the primary exclusive intralabyrinthine tumor. The indications for the different approaches are discussed.

Meta-analysis on the clinical outcomes in patients with intralabyrinthine schwannomas: conservative management vs. microsurgery

The objective of this review is to compare the symptomatological evolution following conservative management (CM) or microsurgery (MS) in patients with intralabyrinthine schwannomas (ILS). A thorough systematic review of the English and French literature from 1948 to February 2014 was performed using Ovid Medline. An ancestor search was also completed. The major inclusion criterion consisted of a diagnosis of ILS with magnetic resonance imaging. Patients with a classic vestibular schwannoma, cases of incidentaloma during surgery or an autopsy were the main exclusion criteria. Thirty-one studies met our selective criteria. Descriptive data were collected from the articles. Clinical outcomes regarding the hearing loss, tinnitus, vertigo, dizziness and aural fullness were stated as improved, unchanged or worse at the last follow-up. All data were then separated into two different groups according to the management option: CM and MS. The data were analyzed using a Pearson χ (2) test and Fisher's exact test. This meta-analysis suggests that MS has a statistically significant favorable outcome regarding symptom relief compared to CM in patients with ILS suffering from tinnitus, vertigo and dizziness. Hearing level was not compared between treatment groups, as MS leads to anacusis. An indicative bias was the main limitation of this study, as patients suffering from intractable vertigo with moderate-to-severe hearing loss were referred to MS. Therefore, in the presence of a serviceable hearing, we suggest that CM should be the treatment of choice.

Intralabyrinthine schwannomas: a case series with discussion of the diagnosis and management

OBJECTIVE

By extracting cases of intralabyrinthine schwannomas (ILS) from the sum of all vestibular schwannomas, we aim to identify and analyze unique features of its presentation. This allows us to refine the management protocol of this rare condition.

DESIGN

This is a retrospective study of all patients seen in the Department of Otorhinolaryngology-Head and Neck Surgery, Rouen University Hospital, with either ILS or ILS with intracanalicular extension (ILS-IAC) between 2001 and 2011. A literature search was performed and results combined to draw conclusions on management strategies.

METHOD

Three patients with ILS and 6 patients with ILS-IAC were identified. We retrieved data on age, sex, symptoms, audiometry, imaging, and management. Pure tone audiometry and speech discrimination score were assessed and hearing classification recorded. Facial nerve function and vestibular function were documented throughout. The diagnostic and surveillance imaging (MRI with or without CT) were reviewed.

RESULTS

The average age at presentation was 62.8 years and the sex ratio was (male: female) 4:5. An ipsilateral hearing loss was observed in all patients. Eight of 9 patients had tinnitus at presentation, 2 had rotatory vertigo, and 1 patient had a facial palsy and hemifacial spasm. In 2 cases, the labyrinthine extension was initially missed. The patient presenting with a large tumor and facial palsy was operated on without delay. The others underwent MRI surveillance, with 4 requiring surgery at a later stage. No postoperative facial palsies were encountered other than the one that had been present preoperatively.

CONCLUSION

Frequency of ILS is underestimated because of poor diagnostic criteria. These tumors have often been described as having features, which resemble Ménière's disease, which is not found in our series. In the absence of tumor progression or disabling symptoms, their management is surveillance/medical, and when surgery is considered, facial paralysis and recurrence rates seem low. The treatment of IAC-ILS differs from that of ILS.

Radiographic association of schwannomas with sensory ganglia

OBJECTIVE

Clinical experience suggests that the majority of schwannomas arise within sensory ganglia, suggesting that intraganglionic glial cells represent a potential cell of origin for schwannomas. To support this clinical impression, we reviewed magnetic resonance imaging (MRI) studies performed over a 5-year period at our institution to determine the relationship of cranial and spinal nerve schwannomas with the ganglia of the associated nerves.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary referral center.

PATIENTS

Patients undergoing imaging study at our institution over a 5-year period.

INTERVENTION(S)

Radiographic images at our institution were reviewed as well as published studies to determine the anatomic location of schwannomas.

MAIN OUTCOME MEASURE(S)

Anatomic location of schwannomas.

RESULTS

A total of 372 patients were found over the 5-year study period, 31 of those were diagnosed with neurofibromatosis Type 2 (NF2). Vestibular schwannomas comprised the greatest number of schwannomas, followed by spinal schwannomas. In NF2 patients, spinal schwannomas were the most common tumor, followed by vestibular schwannomas. In NF2 patients and those with sporadic schwannomas, the overwhelming majority of tumors arose in nerves with a sensory component and were associated with the sensory ganglia of the nerves (562/607, 92.6%). Very few tumors arose from pure motor nerves. This is supported by review of published articles on anatomic location of schwannomas.

CONCLUSION

Schwannomas are strongly associated anatomically with the ganglia of sensory nerves. These findings raise the possibility that intraganglionic glial cells give rise to the majority of schwannomas.

Imaging of sensorineural hearing loss: a pattern-based approach to diseases of the inner ear and cerebellopontine angle

An overview is presented of the common and uncommon diseases of the inner ear and of the cochleovestibular nerve within the internal acoustic meatus and cerebellopontine angle cistern causing sensorineural deafness.

An imaging-pattern-based approach is used to help detect disease and narrow the differential diagnosis.

Main Messages

• The most common soft tissue mass lesions in the cerebellopontine angle are schwannoma and meningioma.

• Contrast-enhanced MRI may reveal clinically unsuspected inflammatory, auto-immune or tumoural disease.

• Hearing loss may be caused by infection, inflammation or, rarely, perineural tumour spread along the cochleovestibular nerve.

• Labyrinthitis may lead to rapidly progressive ossification of the labyrinth.

[Posterior cranial fossa tumours as a cause of sudden hearing deterioration and/or vertigo]

INTRODUCTION

The aim of the work was to analyse sudden deterioration of hearing and/or vertigo occurrence as an early symptom of posterior cranial fossa tumours.

MATERIAL AND METHODS

Among 1.394 people who reported vertigo and hearing impairment and were hospitalised at the Department of Otolaryngology and Laryngological Oncology Military Teaching Hospital in Lodz within the years of 2007-2010 twenty-seven patients were analysed. This group included 19 women aged 20-80 (mean age 45.7 years) and 8 men aged 25-73 (mean age 54.0 years) who had posterior cranial fossa tumours diagnosed on the basis of MRI. Each patient underwent a detailed interview, otorhinolaryngological and otoneurological examinations, pure tone, speech and impedance audiometry, suprathreshold tests (SISI, TDT), tinnitus pitch and frequency evaluation, auditory brainstem response (ABR), complete videonystagmography.

RESULTS

The studied material revealed: acoustic neuroma in 15 patients, cerebellar meningioma in 5 patients, cerebellar cyst in 4 patients and cerebellar angioma in 3 patients. Sudden vertigo was present in 27 patients, including mixed-type vertigo in 15 cases and central vertigo in 12 cases. In 19 patients dizziness was accompanied by tinnitus. In 22 patients hearing disorders were diagnosed in a form of: sensorineural hearing loss in 14 subjects, bilateral in 7 subjects, left-lateral in 5 subjects and right-lateral in 2 subjects respectively, as well as deafness in 8 patients, including left ear deafness in 5 cases, right ear deafness in 1 case and bilateral deafness in 2 cases (7.4%).

CONCLUSIONS

The early phase diagnosis of a posterior cranial fossa tumour as a cause of sudden hearing deterioration and/or vertigo is very seldom and often accidental because GPs, also otolaryngologists, who follow routine and economy, are not used to referring given patients for complete and objective audiological, otoneurological and imaging diagnostics.

EGF and bFGF promote invasion that is modulated by PI3/Akt kinase and Erk in vestibular schwannoma

OBJECTIVES

Vestibular schwannomas (VSs) are slow-growing benign tumors but, on rare occasion, can invade adjacent cranial nerves, causing significant morbidity, especially in association with neurofibromatosis 2 (NF2). We aimed to determine the role of the growth factors EGF, bFGF, and the hormone, Epo, in promoting such invasive behavior in VS, as well as their mechanisms of action.

METHODS

Immunohistochemical staining showed expression of EGFR, bFGF, Epo, EpoR in archived VS tissue. Western blots and immunofluorescence showed expression of EGFR, EpoR and FGF in HEI-193, an immortalized cell line derived from human NF2-related VS. Matrigel invasion assays were used to study the effect of Epo, FGF and bFGF on invasive behavior in HEI-193. Western blotting showed levels of phospho-Akt and phospho-Erk in HEI-193 upon addition of growth factors plus PI3K or MEK inhibitors. Quantitative RT-PCR was performed to determine the expression of MMP2 and MMP9 after treatment with growth factors.

RESULTS

EGFR, bFGF, Epo and EpoR were expressed in VS tissue and HEI193. Addition of EGF and bFGF increased cellular invasion by 10 and 3.5-fold, respectively. Epo had minimal effect on invasion. Results indicated that Erk is involved in bFGF but not EGF-induced invasion, while Akt is involved in both pathways. EGF treatment moderately induced MMP9, but is unlikely to account for the observed invasion.

CONCLUSION

Activation of EGFR and FGFR may promote invasive behavior in VS through ERK and Akt signaling pathways. Further investigation will be necessary to elucidate their potential as useful targets in the treatment of VS.

Management of intralabyrinthine schwannomas

OBJECTIVES

Our protocol to manage the intralabyrinthine schwannoma (ILS).

METHODS

Retrospective chart review of 7 consecutive patients managed for ILS.

RESULTS

Five patients underwent surgical removal of the lesions and none experienced significant complications or recurrent disease. One patient refused surgical treatment and was closely followed by serial MRI scans with no signs of tumor growth. One patient is presently managed conservatively due to a good hearing.

CONCLUSIONS

Diagnosis of ILS is based on high resolution MRI scans and should be included in the differential diagnosis of patients investigated for cochleovestibular symptoms. Treatment modality of ILS is controversial and depends patients' age, severity of vertigo and hearing loss. In the authors' experience surgery is indicated in all cases with invalidating vertigo and in the young patients with severe hearing loss. Conservative strategy is advised in older patients and in cases with preserved good hearing and no invalidating vertigo. These patients must be followed up using high resolution MRI because of the risk of tumor growth into the internal auditory canal. While tumors with exclusive involvement of the inner ear may be removed by means of a completely extradural approach, tumor growth with involvement of the internal auditory canal dictates the necessity of opening the dura exposing the patients to the potential risks associated with the procedure.

Diagnosis and Management of Intracochlear Schwannomas

OBJECTIVE

To describe and analyze a series of intracochlear schwannomas.

METHODS

From 1987 to 2005, 19 patients with schwannomas involving the cochlea were included in this series. Clinical, audiovestibular, and imaging data concerning initial and follow-up visits were collected.

RESULTS

The mean age was 54 years (range, 25-71 yr). The series comprised 10 women and 9 men, 18 solitary tumors and 1 neurofibromatosis Type 2 patient. The mean diagnosis delay was 11 years (range, 1-31 yr). At diagnosis, a total or profound hearing loss (Class D of American Academy of Otolaryngology-Head and Neck Surgery classification) was noted in 17 patients (89%), and a severe loss (Class C) was reported in 2 patients (11%). Facial paresis was reported in 2 patients (11%; Grades 2 and 4 of House and Brackmann classification). Magnetic resonance imaging showed an involvement of the posterior labyrinth in 8 patients (37%), an extension of the schwannoma to the internal auditory meatus in 8 patients (37%), and a cerebellopontine angle extension in 7 patients (32%). In 11 patients (58%), the schwannoma was removed through a transotic route. In the 8 remaining patients, a watch-and-rescan policy was decided. The postoperative course was uneventful. Postoperative follow-up period was 27 months (range, 6-88 mo). Postoperative facial function was assessed as Grade 1 in 7 patients, as Grade 2 in 4, and as Grade 4 in 1 patient.

CONCLUSION

The diagnosis of intracochlear schwannomas can be difficult on magnetic resonance imaging. The diagnosis should be considered in all unilateral hearing losses.

Intrakochleäres Schwannom als Ursache für eine Surditas

Inner ear extension caused by schwannomas, which can cause hearing loss, tinnitus and vertigo, is an extremely rare finding. We report a male patient who presented with progressive hearing loss as well as tinnitus in the right ear. Despite rheologic infusion therapy with glucocorticosteroids at another hospital, the patient showed an explicit hearing loss and vertigo related to the right ear. In the pure tone audiogram, we found complete deafness of the right ear, the equilibriometry with caloric testing showed complete loss of the labyrinth. In the HR-MRI, a structure appeared in ranges of the basal and middle cochlea with enhancement of the contrast medium. From the MRI aspect, this appeared to be a small intracochlear schwannoma. As a differential diagnosis, a chronic granulation is also possible. In agreement with the patient, we decided to control the structure clinically every 6 months using MRI; no further growth of the structure appeared. A precise imaging via HR-MRI is required to detect intracochlear schwannomas. Observation is an appropriate option for patients who have serviceable hearing. Surgical exploration can be recommended in cases of progressive diseases and growth into the inner ear with recurrent vertigo attacks. The option of radiotherapy for the treatment of intrameatal acoustic neurinomas should be considered.

[Benign and malignant lesions in the region of the inner ear and cerebellopontine angle]

Tumorous lesions in the region of the inner ear and cerebellopontine angle are very rare and can be classified into benign and malignant disease forms. This contribution presents and explains the CT and MRI characteristics of these tumors.High-resolution computed tomography (HRCT) in the axial projection is applied for evaluation in the high-resolution bone window. The coronary slices can be reconstructed from the axial datasets or in individual cases examined in the coronary plane.HRCT excellently demonstrates osseous lesions and in individual cases - e.g., exostoses - it can simply suffice to perform HRCT of the temporal bone, while HRCT is also excellent for detecting osseous lesions to determine whether the tumor is benign or malignant.MRI, on the other hand, excellently shows the extent of tumor spread because of its superb soft tissue contrast. Consequently, HRCT and MRI images of the inner ear and cerebellopontine angle provide meaningful information for visualization and classification of tumorous lesions. The two methods should not be considered as competing but rather as complementary and among other aspects exert considerable influence on the therapeutic approach.