Preoperative Differences in Intracranial Facial Versus Vestibular Schwannomas: A Four Nerve Assessment.

OBJECTIVES: Assesses whether preoperative functional testing can distinguish vestibular schwannomas from facial nerve schwannomas medial to the labyrinthine segment. STUDY DESIGN: Retrospective cohort. METHODS: Retrospectively review surgically managed intracranial facial and vestibular schwannomas between January 2015 and December 2019 at two tertiary care centers. Patients with neurofibromatosis 2 and surgery for recurrence were excluded. Preoperative functional testing to include House-Brackmann scores, electroneuronography (ENoG), cervical vestibular evoked myogenic potentials (cVEMP), caloric testing, acoustic brainstem responses (ABRs), acoustic reflexes, and audiograms was compared between the two groups of schwannomas. RESULTS: Twelve facial and 128 vestibular schwannomas met inclusion criteria. In only one case was a facial schwannoma diagnosed preoperatively from imaging. No statistically significant difference was found in preoperative House-Brackmann scores, ENoG, cVEMP, caloric testing, ABRs, or acoustic reflexes. Pure tone average was worse in the vestibular schwannoma group (63 dB [95% CI: 58-68 dB] vs. 46 dB [95% CI: 34-58 dB], P = .01), and the difference was more apparent in the lower frequencies. Word recognition score was better in the facial schwannoma group (66% [95% CI: 45-86%] vs. 41% [95% CI: 34-47%], P = .02). CONCLUSION: Specialized preoperative functional evaluation of the nerves of the internal auditory canal cannot reliably predict the presence of an intracranial facial schwannoma. Hearing is better in facial schwannomas, particularly in the lower frequencies. This should raise the index of suspicion for an intracranial facial schwannoma, especially in candidates for hearing preservation vestibular schwannoma surgery. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2098-2105, 2021.

Stereotactic radiosurgery for facial nerve schwannomas: A preliminary assessment and review of the literature.

OBJECTIVE: Facial nerve schwannomas (FNS) are rare tumors, and their appropriate management remains the subject of considerable debate. This report details the results of a series of patients with FNS treated with stereotactic radiosurgery (SRS) at the University of Virginia. METHODS: We performed a retrospective review of the clinical and imaging outcomes of 5 patients who underwent Gamma Knife RS (GKRS) for small-to-medium-sized (<5 mL) FNS at our institution. The study population consisted of 3 males and 2 females with a median age of 35 years. All patients presented with varying degrees of facial palsy and/or hearing dysfunction. Tumor volumes at GKRS ranged from 0.1 to 5 (median=0.8) mL. The median maximum radiosurgical dose and tumor margin dose were 24 Gy and 12 Gy, respectively. RESULTS: After a median follow-up period of 12 (range, 6-36) months, three tumors were radiographically smaller and two remained stable. Facial function improved in three patients, remained stable in one patient, and slightly declined from House-Brackmann grade I to II in one patient. Hearing function was preserved in three patients and deteriorated in two patients, one from Gardner-Robertson grade I to II and the other from serviceable hearing grade II to III. CONCLUSION: SRS appears to offer a reasonable rate of facial nerve preservation and tumor control for patients with small-to-medium-sized FNS. Considering the published outcomes achieved with resection, RS may be the preferred first-line treatment for these tumors.

Treatment results in the differential surgery of intradural extramedullary schwannoma of 110 cases.

STUDY DESIGN: A retrospective study of intradural extramedullary schwannoma. OBJECTIVE: The purpose of this study was to compare treatment results in the differential surgery of intradural extramedullary schwannoma. BACKGROUND: A reference guide to the surgical procedures available to treat intradural extramedullary schwannoma has not yet been established. METHODS: The study retrospectively reviewed 110 patients: Group A: laminectomy+microscopic excision; Group B: hemilaminectomy+microscopic excision; Group C: laminectomy+microscopic excision+pedicle screw fixation. Researchers selected patients for this retrospective review by applying the following criteria: 1) back pain spread out from the tumor level, sensory and motor loss; 2) treatment by surgery; 3) clinical diagnosis made by physical examination, magnetic resonance imaging (MRI), and pathology; 4) a minimum clinical and radiologic follow-up of 12 months. The clinical outcomes were assessed by comparing the Visual Analogue Pain Scores (VAS) and the Japanese Orthopedic Association Scores (JOA score). The study also performed a cost-effectiveness analysis. RESULTS: Cervical vertebrae: The estimated blood loss in Group B was significantly less than in Group C (P<0.05) (Table 1). Thoracic vertebrae: The duration of hospital stay and estimated blood loss in Group A was significantly less than in Group C (P<0.05) (Table 2, 3). Lumbar vertebrae: The resection rate in Group C was significantly higher than in Group A and Group B (P<0.05) (Table 4). Treatment in Group B was the least expensive, and therefore, the most cost-effective. CONCLUSION: In the case of appropriate surgical indications, the study suggests that hemilaminectomy+microscopic excision is advantageous in the removal of cervical schwannoma, and that laminectomy+microscopic excision is advantageous in the removal of thoracic schwannoma; lumbar intradural extramedullary schwannoma can be managed by laminectomy+microscopic excision+pedicle screw fixation.

Quantitative assessment of whole-body tumor burden in adult patients with neurofibromatosis.

PURPOSE: Patients with neurofibromatosis 1 (NF1), NF2, and schwannomatosis are at risk for multiple nerve sheath tumors and premature mortality. Traditional magnetic resonance imaging (MRI) has limited ability to assess disease burden accurately. The aim of this study was to establish an international cohort of patients with quantified whole-body internal tumor burden and to correlate tumor burden with clinical features of disease. METHODS: We determined the number, volume, and distribution of internal nerve sheath tumors in patients using whole-body MRI (WBMRI) and three-dimensional computerized volumetry. We quantified the distribution of tumor volume across body regions and used unsupervised cluster analysis to group patients based on tumor distribution. We correlated the presence and volume of internal tumors with disease-related and demographic factors. RESULTS: WBMRI identified 1286 tumors in 145/247 patients (59%). Schwannomatosis patients had the highest prevalence of tumors (P = 0.03), but NF1 patients had the highest median tumor volume (P = 0.02). Tumor volume was unevenly distributed across body regions with overrepresentation of the head/neck and pelvis. Risk factors for internal nerve sheath tumors included decreasing numbers of café-au-lait macules in NF1 patients (P = 0.003) and history of skeletal abnormalities in NF2 patients (P = 0.09). Risk factors for higher tumor volume included female gender (P = 0.05) and increasing subcutaneous neurofibromas (P = 0.03) in NF1 patients, absence of cutaneous schwannomas in NF2 patients (P = 0.06), and increasing age in schwannomatosis patients (p = 0.10). CONCLUSION: WBMRI provides a comprehensive phenotype of neurofibromatosis patients, identifies distinct anatomic subgroups, and provides the basis for investigating molecular biomarkers that correlate with unique disease manifestations.

Assessment of pure single nerve root resection in the treatment of spinal schwannoma: focus on solitary spinal schwannomas located below the thoracolumbar junction.

BACKGROUND: The incidence of neurological deficits is reportedly low after sacrificing the affected nerve root during spinal schwannoma treatment. Although the incidence has been widely reported, the operative method for nerve root resection has been not clarified. To evaluate the safety of pure nerve root resection, we focused on solitary spinal schwannomas below the thoracolumbar level and investigated the effect of affected nerve resection. METHODS: Twenty-three spinal schwannoma patients were retrospectively examined. The mean age at surgery was 53 years. We investigated preoperative symptoms, duration of the disorder, postoperative neurological deficits, and clinical outcomes. In addition, we measured tumor size on computed tomography after myelography or on magnetic resonance images using image-analysis software. We retrospectively assessed correlations among duration of symptoms, tumor size, and postoperative neurological deficits. RESULTS: The tumors comprised 19 intradural schwannomas and 4 dumbbell-shaped schwannomas. No postoperative neurological deficits were observed in the intradural schwannoma patients. In contrast, three of the four dumbbell-shaped schwannoma patients experienced postoperative neurological deficits. Among these three patients, two recovered quickly whereas one never recovered. The mean duration of the disorder was 29 months. The postoperative modified JOA score (13.0) was significantly improved compared with the preoperative score (8.9). The mean maximum tumor sizes were 97.2 mm(2) for the intradural schwannomas and 884.0 mm(2) for the dumbbell-shaped schwannomas. There were no correlations among tumor size, duration of the disorder, and postoperative neurological deficits. CONCLUSIONS: On the basis of this study, we recommend pure single nerve resection for treatment of intradural spinal schwannomas before such tumors progress and involve other normal roots, because postoperative neurological deficits did not occur in our intradural schwannoma patients, irrespective of tumor size, when this procedure was used. However, dumbbell-shaped schwannoma patients should be carefully treated operatively, because high incidence of postoperative neurological deficits can be expected.

Schwannoma of cervical sympathetic chain: assessment and management.

Schwannoma arising from the cervical sympathetic chain is an uncommon benign nerve tumour. This tumour most often presents as an asymptomatic solitary neck mass, with slow-growing and rare malignant degeneration. Definitive pre-operative diagnosis may be difficult and investigations are not usually helpful. The carotid artery and internal jugular vein may be displaced anterior-laterally. Diagnosis relies on clinical suspicion and confirmation is often obtained by means of surgical pathology. Surgical excision is the treatment of choice for this tumour, with recurrence being rare. Homer's syndrome is a common post-operative neurological consequence, but does not appear to cause problems to the patient. The case is described of a 42-year-old male who presented an asymptomatic left neck mass. Diagnostic studies included computed tomography, magnetic resonance imaging, and ultrasound which confirmed a circumscribed mass in the upper left portion of the neck next to the thyroid gland. The mass was excised through a transverse left cervical skin incision. Post-operatively the patient showed clinical findings of Horner's syndrome. The pathologic and radiological evaluations, treatment and postoperative complications of this neoplasm are discussed.

Production of diagnostic rules from a neurotologic database with decision trees.

A decision tree is an artificial intelligence program that is adaptive and is closely related to a neural network, but can handle missing or nondecisive data in decision-making. Data on patients with Meniere's disease, vestibular schwannoma, traumatic vertigo, sudden deafness, benign paroxysmal positional vertigo, and vestibular neuritis were retrieved from the database of the otoneurologic expert system ONE for the development and testing of the accuracy of decision trees in the diagnostic workup. Decision trees were constructed separately for each disease. The accuracies of the best decision trees were 94%, 95%, 99%, 99%, 100%, and 100% for the respective diseases. The most important questions concerned the presence of vertigo, hearing loss, and tinnitus; duration of vertigo; frequency of vertigo attacks; severity of rotational vertigo; onset and type of hearing loss; and occurrence of head injury in relation to the timing of onset of vertigo. Meniere's disease was the most difficult to classify correctly. The validity and structure of the decision trees are easily comprehended and can be used outside the expert system.

Decision tree induction in the diagnosis of otoneurological diseases.

Expert systems have been applied in medicine as diagnostic aids and education tools. The construction of a knowledge base for an expert system may be a difficult task; to automate this task several machine learning methods have been developed. These methods can be also used in the refinement of knowledge bases for removing inconsistencies and redundancies, and for simplifying decision rules. In this study, decision tree induction was employed to acquire diagnostic knowledge for otoneurological diseases and to extract relevant parameters from the database of an otoneurological expert system ONE. The records of patients with benign positional vertigo, Meniere's disease, sudden deafness, traumatic vertigo, vestibular neuritis and vestibular schwannoma were retrieved from the database of ONE, and for each disease, decision trees were constructed. The study shows that decision tree induction is a useful technique for acquiring diagnostic knowledge for otoneurological diseases and for extracting relevant parameters from a large set of parameters.

An accurate, cost-effective approach for diagnosing retrocochlear lesions utilizing the T2-weighted, fast-spin echo magnetic resonance imaging scan.

Recent data indicate that the auditory brainstem response (ABR) fails to identify a significant number of retrocochlear lesions. Although the magnetic resonance imaging (MRI) scan with paramagnetic enhancement is highly accurate at detecting these lesions, it is time consuming and expensive. We report on our prospective evaluation of a cohort of 155 patients who underwent T2-weighted, fast-spin echo MRI scans designed to screen for retrocochlear lesions. This imaging technique is rapidly performed and provides superb visualization of the relevant anatomic structures at a global cost of $475. Four tumors were identified with this technique. Cost analysis indicates that supplanting ABR with this limited MRI may well represent a cost-effective approach for evaluating patients with suspected retrocochlear lesions.

[Tumors of the temporal bone and the cerebellopontine angle. Diagnosis, characterization and assessment of extension by using imaging technics]. / Tumori dell'osso temporale e dell'angolo ponto-cerebellare. Diagnosi, caaratterizzazione e bilancio di estensione con le tecniche ad immagini.

We discuss in this paper the reliability of neuroimaging techniques in the diagnosis of neoplastic masses of the posterior-lateral skull base. We also discuss the role of TC and MRI in the evaluation of the extension pattern of these masses.

Assessment and treatment of neurogenic and non-neurogenic tumors of the parapharyngeal space.

The clinical and pathologic findings in eleven cases of parapharyngeal space tumors are described. The anatomy of this area and diagnostic procedures are discussed. Investigations should include a few basic examinations such as sialogram-computed tomographic (CT) scan, carotid angiogram, and echography. Several surgical approaches are considered in relation to the site and the size of the neoplasm. Prognosis depends on the histologic type of the tumor.

[The possibilities of Electric Response Audiometry in Medical Legal Assessment (author's transl)?]. / Was vermag die EEG-Audiometrie bei schwierigen Begutachtungsfållen

A case of nonorganic hearing loss combined with noise-induced hearing loss and the necessity of differentiating them by Electric Response Audiometry in legal assessment is described. A second example deals with monaural functional hearing loss induced by ill-treatment. Finally is reported on a bilateral neurinoma of the acoustical nerve with an extrem auditory fatique and the impossibility to detect evoked potentials.