Audio-vestibular findings in meningioma of the cerebello-pontine angle: a retrospective review

Role of the neurotologist in posterior fossa meningioma surgery

Posterior fossa meningiomas that impinge on structures of the temporal bone or clivus may be difficult to access for optimal resection that maximizes tumor control and minimizes short- and long-term morbidities. To address this challenge, the contemporary neurosurgery-neurotology team works collaboratively by managing patients jointly at every stage of care: preoperative evaluation, intraoperative intervention, and postoperative treatment. The neurotologist is important at all stages of posterior fossa meningioma surgery. First, detailed preoperative evaluation of auditory, facial, vestibular, and lower cranial nerve integrity enables assessment of new neurologic deficit risk, prognosis of functional recovery, and pros and cons of candidate surgical approaches. Second, intraoperative partitioning of surgical steps by provider and adopting an overlapping tumor resection philosophy creates an efficient and confident surgical team built on trust. Third, postoperative closure of cerebrospinal fluid leak and treatment of facial weakness, audiovestibular dysfunction, and voicing and swallowing impairments organized by the neurotologist reduces the impact of negative outcomes. The role of the neurotologist in posterior fossa meningioma surgery is to deliver nuanced evaluative metrics, facilitate shared decision making, perform precise bone and soft tissue microsurgery, and mitigate perioperative morbidities.

Current decision-making in meningiomas

The incidence of meningiomas is rising and the number of incidental cases is increasing steadily. The efficiency and the safety of each treatment strategy are also improving over time. Therefore the indications to treat meningiomas are constantly changing. The aim of meningioma treatment is keeping the patient fully functional while achieving long-term relief or prevention from problems related to intracranial tumor growth. This chapter reviews the natural history and treatment results and aims to put together the information for the most objective decision-making in treating meningiomas. Factors acting on the treatment decision such as anatomical localization, symptomatology, variations in tumor biology, recurrence status, age and co-morbidities, operative gains, and patient preference are individually discussed.

Petrous face meningiomas

Cerebellopontine angle (CPA) meningiomas arise from the petrous face of the temporal bone, which forms the lateral boundary of the CPA. They can be categorized into anterior, middle, and posterior, based on their attachment in relation to the internal acoustic meatus. Each of them presents with their own characteristic clinical syndromes. Because of their close proximity to neurovascular structures, they pose a challenge during surgery. Microsurgery remains the primary treatment modality for large and symptomatic meningiomas. The retrosigmoid approach provides an ideal access for most of the tumors in this location. Radiosurgery is the primary modality of adjuvant therapy for residual, recurrent, and small lesions. Fully fractionated external beam radiotherapy can be used for larger, broader-based residual/recurrent tumors. Management of these complex lesions should include patient preferences and a team approach, including a skull base neurosurgeon, neurotologist, and radiation oncologist.

Petrous Face Meningiomas: Classification, Clinical Syndromes, and Surgical Outcomes

BACKGROUND

Petrous face meningiomas (PFMs) are challenging tumors because of their proximity to the cranial nerves, brainstem, and critical vasculature. The objective of this study is to present surgical outcomes and support an anatomic classification for PFM based on clinical presentation.

METHODS

A retrospective chart review was performed, and 51 PFMs were identified. Tumors were classified by location along the petrous face into anterior, middle, and posterior. Presentation and outcomes were analyzed with logistic regression.

RESULTS

The median follow-up was 31.6 months. Tumors were World Health Organization grade I (n = 50), with 1 World Health Organization grade II tumor. Location was anterior (22%), middle (14%), posterior (53%), and overlapping (12%). Median tumor diameter was 3.0 cm (range, 0.8-6.2 cm). Anterior location was associated with facial pain/numbness on presentation (P < 0.0001), middle location with hearing loss/vestibular dysfunction (P = 0.0035), and posterior with hydrocephalus (P = 0.0190), headache (P = 0.0039), and vertigo (P = 0.0265). Extent of resection was gross total (63%), near total (14%), and subtotal (25%). The observed radiographic recurrence rate was 15%. Mean progression-free survival after diagnosis was 9.1 years with 2-year, 5-year, and 10-year progression-free survival of 91.8%, 78.6%, and 62.9%, respectively. The complication rate was 27%. Age, location, and approach were not associated with complications.

CONCLUSIONS

PFMs present with distinct clinical syndromes based on their location along the petrous face: anterior with trigeminal symptoms, middle with auditory/vestibular symptoms, and posterior with symptoms of mass effect/hydrocephalous. Surgical resection is associated with excellent long-term survival and a low rate of recurrence, which can be managed with radiotherapy.

Audiologic evaluation of vestibular schwannoma and other cerebellopontine angle tumors

CONCLUSION

Otologic accompanying symptoms, audiogram patterns, and hearing levels according to tumor size differed in patients with CPA tumors classified as VS and non-VS types.

OBJECTIVES

The diagnosis of CPA tumors is often delayed. Late-diagnosed tumors can grow until they compress and damage vital structures. This study evaluated the otologic symptoms and results of audiologic tests in patients with vestibular schwannomas (VS) and other types of CPA tumors.

METHODS

This study included 171 patients with otologic symptoms who were diagnosed with CPA tumors, including 116 with VS and 55 with other types of CPA tumors. Factors analyzed retrospectively included tumor type, size, and location and the results of audiometric examinations.

RESULTS

The most common chief complaint in patients diagnosed with CPA tumors was asymmetrical hearing loss, with most frequent accompanying symptoms being tinnitus in patients with VS and dizziness in those with other types of CPA tumor. The most frequent patterns of hearing loss were the descending type in patients with VS and the flat type in patients with non-VS tumors (p < 0.05). Pure tone thresholds tended to increase more in patients with VS than non-VS tumors according to tumor size, and pure tone averages were significantly higher in patients with VS than non-VS tumors of 11-25 mm in size (p < 0.05).

Prospective evaluation of the clinical profile and referral pattern differences of vestibular schwannomas and other cerebellopontine angle tumors

OBJECTIVE

To evaluate the clinical profile, referral pattern, delay in diagnosis, and impact of tumor size of cases involving vestibular schwannomas (VS) versus other cerebellopontine angle (CPA) tumors in an Egyptian population.

STUDY DESIGN

Case series study.

SETTING

Tertiary referral center.

PATIENTS

A prospective study of possible retrocochlear lesions was conducted from 2008 to 2010.

INTERVENTION(S)

Patients were subjected to a full clinical history, complete otorhinolaryngological examination, a basic audiologic evaluation, auditory brainstem response assay, and gadolinium-enhanced magnetic resonance imaging. According to the findings of magnetic resonance imaging, patients with retrocochlear lesions were divided into 2 groups: those with VS (n = 17) and those with other CPA lesions (n = 14).

MAIN OUTCOME MEASURE(S)

Diagnostic delay and criteria of VS and CPA tumors.

RESULTS

Unilateral hearing loss and tinnitus were presented in 52.9% of VS cases with a diagnostic delay of 15.5 months. For cases involving other CPA lesions, a combination of otologic symptoms was observed in 9 (64%) of 14 cases, and a diagnostic delay of 47.5 months was experienced. An absence of auditory brainstem response waves was identified significantly (p < 0.05) for the affected ears of both groups. Only differences in Wave V latency were significant between the 2 groups (p < 0.05).

CONCLUSION

A longer diagnostic delay was associated with cases involving other types of CPA lesions versus cases of VS, and tumor size and volume did not affect the diagnostic delay of the former. Moreover, the only significant difference in clinical presentation for these 2 groups of intracranial tumor involved Wave V latency.

Meningiomas of the internal auditory canal: two case reports

Meningiomas represent 3 to 12% of the tumors that involve the cerebellopontine angle and internal auditory canal (IAC). Intracanalicular meningiomas, however, are rare. Only 10 well-documented cases have been reported in the English literature. The differential diagnosis includes acoustic neuromas, facial nerve neuromas, hemangiomas, lipomas, and meningiomas. We report two new cases of intracanalicular meningioma. Both patients had unilateral tinnitus. In case 1, the patient also experienced sensorineural hearing loss with unilateral tinnitus. In case 1, the lesion appeared hyperintense on T1-weighted and hypointense on T2-weighted magnetic resonance images. In case 2, the patient had an enhancing lesion in the right IAC. The tumors were moderately cellular, and meningeal whorls and meningothelial inclusions were present. Immunohistochemical staining revealed the tumors to be positive for epithelial membrane antigen (EMA) and negative for S-100 protein. The radiologic findings that help distinguish a meningioma from other lesions are reviewed.

Comparison of vestibular function between large cerebellopontine angle meningioma and schwannoma

CONCLUSION

Abnormal caloric and vestibular evoked myogenic potential (VEMP) responses are frequently encountered with a large cerebellopontine angle (CPA) schwannoma, while normal caloric responses and abnormal VEMPs are noted with a large CPA meningioma. This difference may possibly exist because schwannoma causes vestibular deficits via parenchymal involvement, while vestibular deficits in the meningioma are mostly due to compression neuropathy.

OBJECTIVES

This study aimed to compare the tumor characteristics in relation to vestibular function, i.e. caloric and VEMP responses, between large-sized (>2.5 cm) meningioma and schwannoma in the CPA.

PATIENTS AND METHODS

Five patients with large CPA meningioma and nine patients with large CPA schwannoma were enrolled in this study. Each patient underwent a battery of tests including audiometry, caloric test, VEMP test, and MRI study.

RESULTS

The meningioma group showed 20% caloric abnormality and 75% VEMP abnormality, while the schwannoma group revealed 100% caloric and 100% VEMP abnormalities. A significant difference existed in relation to caloric abnormality between the two groups, but not in relation to VEMP abnormality.

Atypical clinical presentations of vestibular schwannomas

A significant number of patients with vestibular schwannomas present atypically, with none of the classical symptoms of unilateral sensorineural hearing loss, tinnitus, and/or dysequilibrium. The aim of this study is to highlight those patients with unusual clinical symptoms.

STUDY DESIGN

The clinical data of all patients who presented to the vestibular schwannoma clinic at Beaumont Hospital over the past 12 years was prospectively recorded in a computerized database. This paper reviews the atypical presenting symptoms.

RESULTS

Three hundred ninety-eight patients were included in this study. A total of 3.7% of patients presented with atypical symptoms only.

CONCLUSION

A significant subgroup, 3.7% in our study, did not present with the audiovestibular symptoms classically associated with vestibular schwannoma. Clinician awareness of the atypical clinical symptoms may lead to earlier detection of these lesions.

Meningiomas involving the internal auditory canal: a diagnostic and surgical challenge

Meningiomas are the second most common lesion encountered within the cerebello-pontine angle (CPA) and rarely project into or originate from the internal auditory meatus (IAM). It is important to distinguish between meningiomas and acoustic neuromas preoperatively as the choice of surgical approach may differ depending on the tumour type. Fortunately, most lesions can be accurately diagnosed with gadolinium-enhanced magnetic resonunce imaging (MRI). We report six cases of meningioma involving the IAM, often leading to an incorrect preoperative MRI diagnosis. We highlight the challenges these tumors present to radiologists and surgeons.

Imaging of the guinea pig cochlea following round window gadolinium application

Precise, non-invasive determination of the aetiology and site of pathology of inner ear disorders is difficult. The aim of this study was to describe an alternative method for inner ear visualization, based on local application of the paramagnetic contrast agent gadolinium. Using a 4.7 T MRI scanner, high contrast images of all four cochlear turns were obtained 3.5 h after placing gadolinium on the round window membrane. Gadolinium cleared from the cochlea within 96 h. Auditory brainstem response measurements performed on a separate group of animals showed no significant threshold shifts after the application, indicating that gadolinium is non-toxic to the guinea pig cochlea.

Meningiomas of the posterior petrous bone: functional outcome after microsurgery

OBJECT

The aim of this study was to analyze a subgroup of patients harboring cerebellopontine angle meningiomas originating from the posterior petrous bone in regard to clinical presentation, surgical anatomy, complications, and long-term functional postoperative results.

METHODS

Data in a series of 51 patients with meningiomas of the posterior petrous bone who had undergone microsurgical treatment at the authors' institution between 1989 and 2002 were retrospectively reviewed. The patient population consisted of 46 women and five men with a mean age of 53 years (range 22-70 years). The main symptom on first admission was impaired hearing in 41%, dizziness in 20%, and tinnitus in 18% of the patients. Results of physical examination and audiological testing revealed hypacusis in 65% of patients, cerebellar ataxia in 31%, and impairment of the fifth cranial nerve in 26%. All patients underwent surgical treatment via a lateral suboccipital approach. Intraoperatively, the tumor was found to be attached to the postmeatal dura in 37%, the premeatal dura in 27.5%, the suprameatal dura in 19.6%, the inframeatal dura in 7.8%, and centered on the porus acusticus in 5.9% of cases. Tumor extension into the internal acoustic meatus was present in seven patients. Tumor resection was categorized as Grade I in 14 patients, Grade II in 29, Grade III in six, and Grade IV in two patients, according to the Simpson classification system. The site of displacement of the cranial nerves was predictable in up to 84% of patients, depending on the dural origin of the tumor as depicted on preoperative magnetic resonance (MR) imaging studies. Postoperatively, a new and permanent facial paresis was observed in five patients (9.8%). In 38 patients in whom both pre- and postoperative audiological data were available, hearing function deteriorated after surgery in 18.4% and improved in 7.9%. Clinical and MR imaging postsurgical data from a mean period of 5.8 years (range 13 months-13 years) were available in all patients. Forty-four patients (86%) resumed normal daily activity. Tumor recurrence was observed in two patients (3.9%), and both underwent a second surgery.

CONCLUSIONS

Preoperative detailed analysis of MR imaging data gives the surgeon a clue about the dislocation of critical neurovascular structures, particularly the cranial nerves. Nonetheless, the exact relationship of the cranial nerves to the tumor (dislocation, adherence, infiltration, and splaying of nerves) can only be fully appreciated during surgery.

Vertigo and dysequilibrium with associated hearing loss

There are numerous disorders that can present with hearing loss and vertigo or dysequilibrium. The combination of vertigo and imbalance associated with hearing loss are symptoms suggestive of a peripheral vestibular disorder. This article summarizes presentation, diagnosis, and treatment of the various common and rare peripheral vestibular disorders that can present with these symptoms.

[Diagnosis of cerebellum-pontine angle tumors using artificial intelligence techniques]

We are concerned in this paper with learning classification procedures from known cases. More precisely, we provide a diagnostic model that discriminate between cerebellum-pontine angle (CPA) tumors and otorhinolaryngological (ENT) disorders. Usually, in order to distinguish between CPA tumors and ENT disorders one must perform clinical-neurological examination together with expensive radiological imagery (CT and MRI). The proposed model was obtained through artificial intelligence methods and presented a good accuracy level (88.4%) when tested against new cases, considering only clinical examination without radiological imagery results.

Clinical features and outcomes in patients with non-acoustic cerebellopontine angle tumours

OBJECTIVES

Non-acoustic tumours of the cerebellopontine angle differ from vestibular schwannomas in their prevalence, clinical features, operative management, and surgical outcome. These features were studied in patients presenting to the regional neuro-otological unit.

METHODS

A retrospective analysis of clinical notes identified 42 patients with non-acoustic tumours of the cerebellopontine angle. Data were extracted regarding presenting clinical features, histopathological data after surgical resection, surgical morbidity and mortality, and clinical outcome (mean 32 months follow up).

RESULTS

The study group comprised 25 meningiomas (60%), 12 epidermoid cysts/cholesteatomata (28%), and five other tumours. In patients with meningiomas, symptoms differed considerably from patients presenting with vestibular schwannomas. Cerebellar signs were present in 52% and hearing loss in only 68%. Twenty per cent of patients had hydrocephalus at the time of diagnosis. After surgical resection, normal facial nerve function was preserved in 75% of cases. In the epidermoid group, fifth, seventh, and eighth nerve deficits were present in 42%, 33%, and 66% respectively. There were no new postoperative facial palsies. There were two recurrences (17%) requiring reoperation. Overall, there were two perioperative deaths from pneumonia and meningitis.

CONCLUSIONS

Patients with non-acoustic lesions of the cerebellopontine angle often present with different symptoms and signs from those found in patients with schwannomas. Hearing loss is less prevalent and cerebellar signs and facial paresis are more common as presenting features. Hydrocephalus is often present in patients presenting with cerebellopontine angle meningiomas. Non-acoustic tumours can usually be resected with facial nerve preservation.