An update on the diagnosis and treatment of vestibular schwannoma

Analysis of the association between vestibular schwannoma and hearing status using a newly developed radiomics technique

PURPOSE

Vestibular schwannoma is a benign tumor originating from Schwann cells surrounding the eighth cranial nerve and can cause hearing loss, tinnitus, balance problems, and facial nerve disorders. Because of the slow growth of the tumor, predicting the hearing function of patients with vestibular schwannoma's is important to obtain information that would be useful for deciding the treatment modality. This study aimed to analyze the association between magnetic resonance imaging features and hearing status using a new radiomics technique.

METHODS

We retrospectively analyzed 115 magnetic resonance images and hearing results from 73 patients with vestibular schwannoma. A total of 70 radiomics features from each tumor volume were calculated using T1-weighted magnetic resonance imaging. Radiomics features were classified as histogram-based, shape-based, texture-based, and filter-based. The least absolute shrinkage and selection operator method was used to select the radiomics features among the 70 features that best predicted the hearing test. To ensure the stability of the selected features, the least absolute shrinkage and selection operator method was repeated 10 times. Finally, features set five or more times were selected as radiomics signatures.

RESULTS

The radiomics signatures selected using the least absolute shrinkage and selection operator method were: minimum, variance, maximum 3D diameter, size zone variance, log skewness, skewness slope, and kurtosis slope. In random forest, the mean performance was 0.66 (0.63-0.77), and the most important feature was Log skewness.

CONCLUSIONS

Newly developed radiomics features are associated with hearing status in patients with vestibular schwannoma and could provide information when deciding the treatment modality.

18F-FDG PET/CT revealed sporadic schwannomatosis involving the lumbar spinal canal and both lower limbs: a case report

Schwannomatosis is a rare autosomal dominant hereditary syndrome disease characterized by multiple schwannomas throughout the body, without bilateral vestibular schwannoma or dermal schwannoma. The most common location of schwannomatosis is the head and neck, as well as the limbs, while multiple schwannomas in the lumbosacral canal and lower extremities are relatively rare. In this study, we report a 79-year-old woman diagnosed with schwannomatosis. MRI and contrast-enhanced imaging revealed multiple schwannomas in both lower extremities. An 18F-FDG PET/CT examination revealed that in addition to multiple tumors with increased 18F-FDG uptake in both lower extremities, there was also an increased 18F-FDG uptake in a mass in the lumbosacral canal. These masses were confirmed to be schwannomas by pathology after surgery or biopsy. 18F-FDG PET/CT findings of schwannomas were correlated with MRI and pathological components. Antoni A area rich in tumor cells showed significant enhancement on contrast-enhanced T1WI, and PET/CT showed increased uptake of 18F-FDG in the corresponding area, while Antoni B region rich in mucus showed low enhancement on contrast-enhanced T1WI, accompanied by a mildly increased 18F-FDG uptake.

Case Report: Use of novel AR registration system for presurgical planning during vestibular schwannoma resection surgery

Background and importance

Vestibular schwannomas are benign tumors and are the most common tumor found in the cerebellopontine angle. Surgical management of these lesions involves consideration of various operative approaches, which can have profound effects on procedural course and patient outcomes. Therefore, a comprehensive understanding of the location of the tumor and surrounding anatomical structures is vital for a positive outcome. We present a case of a 47-year-old female patient with vestibular schwannoma. A novel mixed reality (MR) system was used to register patient-specific 3D models onto the patient's head for operative planning and anatomical visualization.

Case description

A 47-year-old female presented with a history of left-sided hearing loss, tinnitus, and episodic left facial tingling. Magnetic Resonance Imaging (MRI) demonstrated a 3.3 cm enhancing lesion in the left cerebellopontine angle at the with mass effect on the brachium pontis and medulla. Surgical resection was performed via retrosigmoid craniotomy.

Conclusions

In this study, we report the use of Augmented Reality (AR) visualization for planning of vestibular schwannoma resection. This technology allows for efficient and accurate registration of a patient's 3D anatomical model onto their head while positioned in the operating room. This system is a powerful tool for operative planning as it allows the surgeon to visualize critical anatomical structures where they lie on the patient's head. The present case demonstrates the value and use of AR for operative planning of complex cranial lesions.

Clinical practice guideline on the management of vestibular schwannoma

INTRODUCTION

Vestibular schwannoma (VS) is the most common tumour of the cerebellopontine angle. The greater accessibility to radiological tests has increased its diagnosis. Taking into account the characteristics of the tumour, the symptoms and the age of the patient, three therapeutic strategies have been proposed: observation, surgery or radiotherapy. Choosing the most appropriate for each patient is a frequent source of controversy.

MATERIAL AND METHODS

This paper includes an exhaustive literature review of issues related to VS that can serve as a clinical guide in the management of patients with these lesions. The presentation has been oriented in the form of questions that the clinician usually asks himself and the answers have been written and/or reviewed by a panel of national and international experts consulted by the Otology Commission of the SEORL-CCC.

RESULTS

A list has been compiled containing the 13 most controversial thematic blocks on the management of VS in the form of 50 questions, and answers to all of them have been sought through a systematic literature review (articles published on PubMed and Cochrane Library between 1992 and 2023 related to each thematic area). Thirty-three experts, led by the Otology Committee of SEORL-CCC, have analyzed and discussed all the answers. In Annex 1, 14 additional questions divided into 4 thematic areas can be found.

CONCLUSIONS

This clinical practice guideline on the management of VS offers agreed answers to the most common questions that are asked about this tumour. The absence of sufficient prospective studies means that the levels of evidence on the subject are generally medium or low. This fact increases the interest of this type of clinical practice guidelines prepared by experts.

Contrast-enhanced CT rim sign may predict vestibular schwannoma adhesion and postoperative complications

AIM

To investigate the clinical and radiological features to predict adhesion between vestibular schwannoma (VS) and brain tissue which is a critical risk factor for postoperative infarction and residual tumour.

MATERIAL AND METHODS

One hundred and seven consecutive VS surgeries were analysed. After excluding cases without contrast-enhanced (CE) computed tomography (CT), Koos grades 1 and 2, and cases with incomplete clinical data, 44 patients were finally included in the study. Enhancement of the tumour capsule on the brainstem side on CE-CT was defined as the CE-CT rim sign, which was analysed along with clinical characteristics, including tumour adhesion and postoperative complications.

RESULTS

Eight patients exhibited CE-CT rim signs; 17 had tumour adhesions. Four patients had postoperative infarction at the ipsilateral middle cerebellar peduncle; 18 exhibited postoperative infarction and/or residual tumour at the middle cerebellar peduncle. The CE-CT rim sign significantly correlated with tumour adhesion, postoperative infarction, and postoperative infarction and/or residual tumour in the cerebellar peduncle. Univariate regression analysis revealed that the CE-CT rim sign significantly correlated with tumour adhesion (odds ratio [OR] 6.81, 95% confidence interval [CI] 1.18-39.25, p=0.032) and postoperative infarction and/or residual tumour at the cerebellar peduncle (OR 6.00, 95% CI 1.04-34.31, p=0.044).

CONCLUSION

The CE-CT rim sign was identified in 18.2% of patients with VS and significantly correlated with tumour adhesion and postoperative complications, such as postoperative infarction and residual tumour. This study highlights the importance of the preoperative CE-CT rim sign in VS, which is predictive of tumour adhesion and postoperative complications.

Infratemporal Fossa Schwannoma Surgery via a Combined Prelacrimal Recess, Caldwell-Luc, and Distal Intraoral Approach

BACKGROUND

The deep location of infratemporal fossa (ITF) combined with the abundant vascular plexus in it increased the difficulty of removing the mass in ITF through endoscope surgery approach. However, under appropriate circumstances, the excision of ITF tumors through a combined prelacrimal recess, Caldwell-Luc, and distal intraoral approach can be safely performed with minimal impact on the surrounding tissues.

CASE PRESENTATION

The Department of Neurology received a 69-year-old male patient who had been experiencing headache, dizziness, and numbness from the mastoid region of his left ear to the corner of his mouth for a duration of 22 days. Cranial magnetic resonance imaging revealed the presence of a tumor located in the ITF. Following transfer to our department, surgical intervention was performed using a combined approach involving the prelacrimal recess, the anterior wall of maxillary sinus, and lateral ITF to successfully remove the tumor. Postoperative pathologic examination confirmed schwannoma as its nature. The patient was discharged in excellent condition without any functional impairment.

CONCLUSIONS

On the basis of this case, the authors believe that this combined approach can offer a distinct endoscopic perspective and adequate surgical workspace, which is crucial for tumor removal while preserving the integrity of surrounding normal tissues. Moreover, the utilization of multiple small incisions has minimal impact on postoperative recovery.

Quality of life in patients after vestibular schwannoma surgery

AIM

To evaluate the most important factors of quality of life in patients after vestibular schwannoma surgery.

MATERIALS AND METHODS

Patients with unilateral sporadic occurrence of vestibular schwannoma who underwent surgery via suboccipital-retrosigmoid approach were included in the prospective study (2018-2021). Patients after previous Leksell gamma knife irradiation (or other methods of stereotactic radiosurgery) were excluded. Quality of life was assessed using 10 validated questionnaires that were distributed preoperatively, 3 months and 1 year after the surgery.

RESULTS

A total of 76 patients were included in the study, complete data were analysed in 43 of them (response rate 57%). Grade III and IV represented up to 70% of all tumors. Patients with larger tumors had a significantly higher risk of postoperative facial nerve paresis, liquorrhea and lower probability of hearing preservation. Patients with smaller tumors and those, who suffered from headaches before surgery had more frequent and severe headaches after surgery. Postoperative headaches were associated with higher incidence of anxiety and tinnitus. More frequent anxiety was also identified in patients with preoperative serviceable hearing who became deaf after surgery. Nevertheless, tinnitus and hearing impairment appeared to have less impact on overall quality of life compared to headaches and facial nerve function.

CONCLUSION

According to our results, tumor size, postoperative function of the facial nerve and occurrence of postoperative headaches had the greatest influence on the overall postoperative quality of life in patients after vestibular schwannoma surgery.

Identification of hub genes and drug candidates for NF2-related vestibular schwannoma by bioinformatics tools

Neurofibromatosis type 2 (NF2)-related vestibular schwannoma (NF2-VS) is a rare genetic disorder that results in bilateral acoustic neuromas. However, the exact pathogenesis of the disease is still unclear. This study aims to use bioinformatics analyses to identify potential hub genes and therapeutic. We retrieved the mRNA expression profiles (GSE108524 and GSE141801) of NF2-VS from the database, and selected the leading 25% genes with the most variance across samples for weighted correlation network analysis. Subsequently, we conducted gene ontology term and Kyoto Encyclopedia of Genes and Genomes signaling network enrichment analyses. The STRING database was employed for protein-protein interaction (PPI) axis construction. The mRNA-miRNA modulatory network was generated via the miRTarBase database. Differentially expressed genes (DEGs) were identified via the R package "limma" in both datasets, and hub genes were screened via intersection of common DEGs, candidate hub genes from the PPI axis, and candidate hub genes from the key module. Finally, common DEGs were uploaded onto the connectivity map database to determine drug candidates. Based on our observations, the blue module exhibited the most significant relation to NF2-VS, and it included the NF2 gene. Using enrichment analysis, we demonstrated that the blue modules were intricately linked to modulations of cell proliferation, migration, adhesion, junction, and actin skeleton. Overall, 356 common DEGs were screened in both datasets, and 33 genes carrying a degree > 15 were chosen as candidate hub genes in the PPI axis. Subsequently, 4 genes, namely, GLUL, CAV1, MYH11, and CCND1 were recognized as real hub genes. In addition, 10 drugs with enrichment scores < -0.7 were identified as drug candidates. Our conclusions offered a novel insight into the potential underlying mechanisms behind NF2-VS. These findings may facilitate the identification of novel therapeutic targets in the future.

Brazilian Society of Otology task force - Vestibular Schwannoma ‒ evaluation and treatment

OBJECTIVE

To review the literature on the diagnosis and treatment of vestibular schwannoma.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on vestibular schwannoma were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: (1) Diagnosis - audiologic, electrophysiologic tests, and imaging; (2) Treatment - wait and scan protocols, surgery, radiosurgery/radiotherapy, and systemic therapy.

CONCLUSIONS

Decision making in VS treatment has become more challenging. MRI can diagnose increasingly smaller tumors, which has disastrous consequences for the patients and their families. It is important to develop an individualized approach for each case, which highly depends on the experience of each surgical team.

Hearing loss and vestibular schwannoma: new insights into Schwann cells implication

Hearing loss (HL) is the most common and heterogeneous disorder of the sensory system, with a large morbidity in the worldwide population. Among cells of the acoustic nerve (VIII cranial nerve), in the cochlea are present the hair cells, the spiral ganglion neurons, the glia-like supporting cells, and the Schwann cells (SCs), which alterations have been considered cause of HL. Notably, a benign SC-derived tumor of the acoustic nerve, named vestibular schwannoma (VS), has been indicated as cause of HL. Importantly, SCs are the main glial cells ensheathing axons and forming myelin in the peripheral nerves. Following an injury, the SCs reprogram, expressing some stemness features. Despite the mechanisms and factors controlling their biological processes (i.e., proliferation, migration, differentiation, and myelination) have been largely unveiled, their role in VS and HL was poorly investigated. In this review, we enlighten some of the mechanisms at the base of SCs transformation, VS development, and progression, likely leading to HL, and we pose great attention on the environmental factors that, in principle, could contribute to HL onset or progression. Combining the biomolecular bench-side approach to the clinical bedside practice may be helpful for the diagnosis, prediction, and therapeutic approach in otology.

Cochlear radiation dose and hearing loss in patients with vestibular schwannoma undergoing radiosurgery: systematic review

OBJECTIVES

To determine the cut-off point of the cochlear radiation dose as a risk factor for hearing loss in patients with vestibular schwannoma treated with radiosurgery.

METHODS

A systematic review of the literature was performed without language or publication year restrictions in the MEDLINE/PubMed, EMBASE, Web of Science, LILACS/VHL and Cochrane Library databases. Studies that met the following criteria were included: 1) population: adults of both sexes who underwent radiosurgery for vestibular schwannoma treatment; 2) exposure: cochlear radiation; 3) outcome: hearing loss; 4) type of study: cohort. Two independent reviewers conducted the entire review process. The registration number in PROSPERO was CRD42020206128.

RESULTS

From the 333 articles identified in the searches, seven were included after applying the eligibility criteria. There was no standardization as to how to measure exposure or outcome in the included studies, and most studies did not present sufficient data to enable meta-analysis.

CONCLUSION

It was not possible to determine a cut-off point for high cochlear dose that could be considered a risk factor for hearing loss.

Hearing Aid in Vestibular-Schwannoma-Related Hearing Loss: A Review

(1) Background: Several types of hearing aids are available for the rehabilitation of vestibular-schwannoma (VS)-related hearing loss. There is a lack of recently published papers regarding this theme. The aim of the present work is to organize current knowledge. (2) Methods: A review of the literature regarding the topics "vestibular schwannoma", "hearing loss", and "hearing aid" was performed. Nineteen studies were thus considered. (3) Results: Conventional hearing aids, contralateral routing of signal (CROS) aids, bone anchored hearing aids (BAHA), and others are available options for hearing rehabilitation in VS patients. The speech discrimination score (SDS) is considered the best measure to assess candidacy for rehabilitation with hearing aids. The best hearing rehabilitative conditions in VS patients when using conventional hearing aid devices are a mild-moderate hearing loss degree with good word recognition (more than 50% SDS). CROS-Aid and BAHA are reported to be beneficial. CROS-Aid expands on the area of receiving hearing. BAHA aids use direct bone-conduction stimulation. Unfortunately, there are no available studies focused specifically on VS patients that compare CROS and BAHA technologies. (4) Conclusions: Hearing aids, CROS, and BAHA are viable options for rehabilitating hearing impairment in VS, but require an accurate case-by-case audiological evaluation for rehabilitating hearing impairment in VS. Further studies are needed to prove if what is currently known about similar hearing illnesses can be confirmed, particularly in the case of VS.

Thermal Analysis of an Ultrasonic Aspirator Micro Claw Tool Compared With Standard High-Speed Drilling During Internal Auditory Canal Opening in a Cadaveric Model

BACKGROUND

The ultrasonic aspirator micro claw tool (UAmCT) can be used to remove the bone of the internal auditory canal (IAC) during vestibular schwannoma resection via the retrosigmoid approach (RSA) without the risk of a spinning drill shaft. However, the thermal profile of the UAmCT during IAC removal has not been reported.

OBJECTIVE

To compare the thermal profile of the UAmCT during access of the IAC to that of a conventional high-speed drill (HSD) and to present an illustrative case of this application.

METHODS

IAC opening via RSA was performed in 5 embalmed cadaveric specimens using the UAmCT with 3, 8, and 15 mL/min irrigation on the left and the HSD at 75 000 revolutions per minute and 0%, 14%, and 22% irrigation on the right. Peak bone surface temperatures were measured 4 times in 20-second intervals, and statistical analyses were performed using SPSS software. An illustrative case of a vestibular schwannoma resected via an RSA using the UAmCT to access the IAC is presented.

RESULTS

The IAC was opened in all 5 specimens using both the UAmCT and HSD without complication. The mean peak bone surface temperatures were significantly lower with the UAmCT compared with the HSD ( P < .001). The UAmCT did not meaningfully prolong the operating time in the illustrative case, and the IAC was accessed without complication.

CONCLUSION

The UAmCT may be a safe and effective alternative to HSD for IAC opening during vestibular schwannoma resection via the RSA. Larger studies under clinical conditions are required to further validate these findings.

Full Endoscopic Resection of Intralabyrinthine Schwannomas: A Case Series

Objective: To investigate the technique and efficacy of fully endoscope resection of intralabyrinthine schwannomas (ILS) by transcanal transpromontorial endoscopic approach (TTEA). Study Design: Retrospective case review. Setting: Hospital. Patients: All patients who were affected by ILS, without extension to the internal auditory canal and underwent surgery with TTEA in our hospital in 2020. Intervention(s): Therapeutic. Main Outcome Measure(s): Recovery status, postoperative complications and remaining symptoms after surgery. Results: Three patients were included, all of which underwent gross total resections. The follow-up period was from 10 months to 2 years. No intraoperative and postoperative major complications were observed. There was no facial paralysis or cerebrospinal fluid leakage postoperatively. The hospitalization time of TTEA was 5 days. Three patients' vertigo was relieved after 1 week without receiving vestibular therapy. Only 1 patient complained of transient episodes of vertigo when climbing or holding heavy objects. Conclusions: TTEA has the advantages of clear vision to identify the anatomical structure, enabling complete tumor resection, reduced operation time, and faster postoperative recovery.Level of Evidence: IV.

Does vestibular function correlate with objective MRI findings after vestibular schwannoma surgery?

Objective

Vestibular schwannoma surgery leads to acute unilateral vestibular loss. In some patients, however, the process of post-operatively initiated central compensation proceeds more rapidly than in others. This study aimed to evaluate post-operative vestibular function and correlate it with morphological findings of MRI scans.

Methods

The study included 29 patients who underwent surgery for vestibular schwannoma. Vestibular function was analysed post-operatively by video head impulse test (vHIT). Subjective symptoms were evaluated using validated questionnaires. All patients underwent MRI 3 months post-operatively, and the presence of the facial and vestibulocochlear nerves in the internal auditory canal was assessed.

Results

The vestibulo-ocular reflex gain measured by the vHIT correlated positively with audiological findings. Subjective perception of vestibular disorder did not correlate with objectively measured vestibular impairment or with MRI findings.

Conclusions

After the resection of vestibular schwannoma, some patients may still have preserved vestibular function as measured by vHIT. The preserved function does not correlate with subjective symptoms. Patients with partially deteriorated vestibular function showed lower sensitivity to combined stimuli.

Simultaneous Cochlear Implantation and Salvage Translabyrinthine Resection of Vestibular Schwannoma after Radiotherapy

OBJECTIVE

To report on the novel use of simultaneous cochlear implantation (CI) during salvage translabyrinthine resection of vestibular schwannoma (VS) after failed stereotactic radiosurgery (SRS).

PATIENT

A 52-year-old woman presented with a medium-sized right VS. She experienced continued tumor growth despite previous SRS, resulting in medial extension beyond the internal auditory canal into the cerebellopontine angle. Associated symptoms included asymmetrical right moderate to severe sensorineural hearing loss, poor word recognition, tinnitus, and dizziness.

INTERVENTION

Simultaneous CI with translabyrinthine VS resection.

MAIN OUTCOME MEASURE

CI-aided pure-tone averages.

RESULTS

After 4 months of device use, CI-aided speech audiometry revealed hearing thresholds in the normal range, with a four-tone pure-tone, average of 16.3 dB. Speech perception with consonant-nucleus-consonant testing in the CI-only condition was 46%, representing a 12% improvement compared with preoperatively. Tinnitus and dizziness burden were subjectively reduced.

CONCLUSIONS

Despite challenges inherent to second procedures after radiotherapy failure, successful CI outcomes can be achieved. The current study demonstrates the feasibility of simultaneous CI during salvage VS resection after SRS. A larger study should be undertaken to further substantiate these preliminary findings.

Intraoperative Cochlear Nerve Monitoring in Cochlear Implantation after Vestibular Schwannoma Resection

BACKGROUND

The use of a cochlear implant (CI) for hearing rehabilitation after vestibular schwannoma (VS) resection is widely spreading. The procedure is usually performed simultaneously to tumor resection with a translabyrinthine approach. To ensure the best device function, assessing the integrity of the cochlear nerve is of primary importance.

METHODS

A narrative review of the literature on the present topic was carried out up to June 2022. Finally, nine studies were considered.

RESULTS

Electrically evoked auditory brainstem responses (eABR) is the most widely used method of intraoperative monitoring of cochlear nerve (CN) during VS resection, although its limits are known. It can be assessed through the CI electrode array or through an intracochlear test electrode (ITE). Variations of the graph are evaluated during the surgical procedure, in particular the wave V amplitude and latency. As tumor dissection progresses, the parameters may change, informing of the CN status, and the surgical procedure may be modulated.

CONCLUSION

An eABR positive result seems to be reliably correlated with a good CI outcome in those cases in which a clear wave V is recorded before and after tumor removal. On the contrary, in those cases in which the eABR is lost or altered during the surgical procedure, the positioning of a CI is still debatable.

The genetic landscape and possible therapeutics of neurofibromatosis type 2

Neurofibromatosis type 2 (NF2) is a genetic condition marked by the development of multiple benign tumors in the nervous system. The most common tumors associated with NF2 are bilateral vestibular schwannoma, meningioma, and ependymoma. The clinical manifestations of NF2 depend on the site of involvement. Vestibular schwannoma can present with hearing loss, dizziness, and tinnitus, while spinal tumor leads to debilitating pain, muscle weakness, or paresthesias. Clinical diagnosis of NF2 is based on the Manchester criteria, which have been updated in the last decade. NF2 is caused by loss-of-function mutations in the NF2 gene on chromosome 22, leading the merlin protein to malfunction. Over half of NF2 patients have de novo mutations, and half of this group are mosaic. NF2 can be managed by surgery, stereotactic radiosurgery, monoclonal antibody bevacizumab, and close observation. However, the nature of multiple tumors and the necessity of multiple surgeries over the lifetime, inoperable tumors like meningiomatosis with infiltration of the sinus or in the area of the lower cranial nerves, the complications caused by the operation, the malignancies induced by radiotherapy, and inefficiency of cytotoxic chemotherapy due to the benign nature of NF-related tumors have led a march toward exploring targeted therapies. Recent advances in genetics and molecular biology have allowed identifying and targeting of underlying pathways in the pathogenesis of NF2. In this review, we explain the clinicopathological characteristics of NF2, its genetic and molecular background, and the current knowledge and challenges of implementing genetics to develop efficient therapies.

Vestibular Impairment in Patients with Vestibular Schwannoma: A Journey through the Pitfalls of Current Literature

Vestibular Schwannoma is the most common tumour of Ponto Cerebellar Angle and is capable of strongly impacting the patient's quality of life. In recent decades, the proposals for the management of the disease have multiplied, just as the diagnostic capacity has improved. While in the past, the primary objective was the preservation of the facial function, and subsequently also of the auditory function, the attention to the vestibular symptomatology, which appears to be one of the main indicators of deterioration of quality of life, is still unsatisfactory. Many authors have tried to provide guidance on the best possible management strategy, but a universally recognized guideline is still lacking. This article offers an overview of the disease and the proposals which have advanced in the last twenty years, evaluating their qualities and defects in a critical reading.

Schwannoma (neurilemmoma) of tongue: A rare case presentation and review of literature

It seems that schwannomas of the tongue base originate from branches of the glossopharyngeal, vagus, or hypoglossal nerves. Additionally, complete trans-oral surgical excision is an efficient method to remove them.

The study of predictive factors for the evolution of vestibular schwannomas

PURPOSE

The primary objective was to determine whether the analysis of textural heterogeneity of vestibular schwannomas on MRI at diagnosis was predictive of their radiological evolutivity. The secondary objective was to determine whether some clinical or radiological factors could also be predictive of growth.

METHODS

We conducted a pilot, observational and retrospective study of patients with a vestibular schwannoma, initially monitored, between April 2001 and November 2019 within the Oto-Neurosurgical Institute of Champagne Ardenne, Texture analysis was performed on gadolinium injected T1 and CISS T2 MRI sequences and six parameters were extracted: mean greyscale intensity, standard deviation of the greyscale histogram distribution, entropy, mean positive pixels, skewness and kurtosis, which were analysed by the Lasso method, using statistically penalised Cox models. Extrameatal location, tumour necrosis, perceived hearing loss < 2 years with objectified tone audiometry asymmetry, tinnitus at diagnosis, were investigated by the Log-Rank test to obtain univariate survival analyses.

RESULTS

78 patients were included and divided into 2 groups: group A comprising 39 "stable patients", and B comprising the remaining 39 "progressive patients". Independent analysis of the texture factors did not predict the growth potential of vestibular schwannomas. Among the clinical or radiological signs of interest, hearing loss < 2 years was identified as a prognostic factor for tumour progression with a significant trend (p = 0.05).

CONCLUSIONS

This study did not identify an association between texture analysis and vestibular schwannomas growth. Decreased hearing in the 2 years prior to diagnosis appears to predict potential radiological progression.

Proton Radiotherapy for Vestibular Schwannomas in Patients with NF2-Related Schwannomatosis: A Case Series

(1) Background: This study aimed to evaluate the efficacy and treatment-related toxicity of proton radiotherapy (PRT) for vestibular schwannoma (VS) in patients with neurofibromatosis type 2-related schwannomatosis (NF2). (2) Methods: Consecutive NF2 patients treated with PRT for VS between 2004 and 2016 were retrospectively evaluated, focusing on tumor volume, facial and trigeminal nerve function, hearing, tinnitus, vestibular symptoms, and the need for salvage therapy after PRT. (3) Results: Eight patients were included (median age 36 years, 50% female). Median follow-up was 71 months. Five (63%) patients received fractionated PRT and three (38%) received PRT radiosurgery for VS. Six patients (75%) received prior VS surgery; three also received bevacizumab. Six patients (75%) did not require salvage therapy after PRT. Two patients (25%) with residual hearing lost it after PRT, and six had already lost ipsilateral hearing prior to PRT. Tumor and treatment-related morbidity could be evaluated in six patients. Following PRT, conditions that occurred or worsened were: facial paresis in five (83%), trigeminal hypoesthesia in two (33%), tinnitus in two (33%), and vestibular symptoms in four patients (67%). (4) Conclusion: After PRT for VS, the majority of the NF2 patients in the cohort did not require additional therapy. Tumor and/or treatment-related cranial nerve deficits were common. This is at least partly explained by the use of PRT as a salvage treatment after surgery or bevacizumab, in the majority of cases. There remains the further opportunity to elucidate the efficacy and toxicity of proton radiotherapy as a primary treatment.

Hearing Preservation, Facial Nerve Dysfunction, and Tumor Control in Small Vestibular Schwannoma: A Systematic Review of Gamma Knife Radiosurgery Versus Microsurgery

BACKGROUND AND PURPOSE

Vestibular schwannoma (VS) is the most common type of tumor found in the cerebellopontine angle that accounts for 8% of all intracranial tumors. VS management is currently a challenge due to the unpredictable nature of the tumor. Few studies have compared the results and complications of various therapeutic approaches to VS. Therefore, as a treatment option for VSs smaller than 25 mm, we conducted a systematic review to compare Gamma Knife radiosurgery (GKRS) with conventional surgery.

METHODS

Literature searches were conducted of four online databases (PubMed, Google Scholar, Cochrane, and ScienceDirect) using the following keyword search: ("vestibular schwannoma" OR "acoustic neuroma") AND ("gamma knife" OR "gamma knife radiosurgery") AND ("resection" OR "open surgery") AND ("hearing preservation" OR "facial nerve" OR "tumor growth").

RESULTS

We identified six retrospective cohort studies, five of which were of fair-to-good quality. All studies showed that GKRS was superior to surgery in hearing preservation. Two studies indicated that surgery was superior to GKRS in maintaining tumor control, one indicated that GKRS was superior, and the remainder indicated that there was no significant difference in maintaining tumor control between GKRS and microsurgery.

CONCLUSIONS

Based on the three outcomes chosen for this review, GKRS was superior to microsurgery in small VS.

Surgery versus radiosurgery for vestibular schwannoma: Shared decision making in a multidisciplinary clinic

Background

Our neurosurgical unit adopted a model of shared decision-making (SDM) based on multidisciplinary clinics for vestibular schwannoma (VS). A unique feature of this clinic is the interdisciplinary counseling process with a surgeon presenting the option of surgery, an oncologist radiosurgery or radiotherapy, and a specialist nurse advocating for the patient.

Methods

This is a retrospective cohort study. All new patients seen in the combined VS clinic and referred from the skull base multidisciplinary team (MDT) from beginning of June 2013 to end of January 2019 were included. Descriptive statistics and frequency analysis were carried out for the full cohort.

Results

Three hundred and fifty-four patients presenting with new or previously untreated VS were included in the analysis. In our cohort, roughly one-third of patients fall into each of the treatment strategies with slightly smaller numbers of patients undergoing surgery than watch, wait and rescan (WWR) ,and SRS (26.6% vs. 32.8% and 37.9%, respectively).

Conclusion

In our experience, the combined surgery/oncology/specialist nurse clinic streamlines the patient experience for those with a VS suitable for either microsurgical or SRS/radiotherapy treatment. Decision-making in this population of patients is complex and when presented with all treatment options patients do not necessarily choose the least invasive option as a treatment. The unique feature of our clinic is the multidisciplinary counseling process with a specialist nurse advocating and guiding the patient. Treatment options are likely to become more rather than less complex in future years making combined clinics more valuable than ever in the SDM process.

The Diagnostic Accuracy of Pure-Tone Audiometry Screening Protocols for Vestibular Schwannoma in Patients with Asymmetrical Hearing Loss-A Systematic Review and Meta-Analysis

(1) Background: Magnetic resonance imaging (MRI) is the gold standard investigation for all patients who present with asymmetrical hearing loss (AHL) and a high index of suspicion for vestibular schwannoma (VS). However, pure-tone audiometry (PTA) is an investigation that can be used for the screening of these patients in order to reduce the costs. The aim of this systematic review and meta-analysis was to evaluate the diagnostic accuracy of different PTA protocols for VS in patients with ASHL, when compared with MRI; (2) Methods: Medline, Embase, and Cochrane databases were used to find relevant studies. All prospective and retrospective observational studies that evaluated the accuracy of PTA protocols for the screening of VS were assessed, according to the international guidelines; (3) Results: We analyzed seven studies (4369 patients) of poor-to-moderate quality. Their pooled sensitivity was good (0.73-0.93), but their specificity was low (0.31-0.60). All protocols were located in the right lower quadrant on the likelihood scattergram, and the post-test probabilities for positive and negative diagnosis of these protocols were extremely low; (4) Conclusions: PTA protocols cannot be used for a proper screening or diagnosis of vestibular schwannoma despite their good sensibility, and MRI remains the gold standard for this purpose.

β 2 -Microglobulin Participates in the Development of Vestibular Schwannoma by Regulating Nuclear Factor-κB

BACKGROUND AND OBJECTIVES

Vestibular schwannoma (VS), the most common intercranial schwannoma, originates from the sheath of the vestibular nerve. The growth rate of VS varies greatly, with the tumor enlarging gradually, which can compress the peripheral nerve tissue and reveal corresponding symptoms. This study was aimed to elucidate the growth mechanism of VS by analyzing cellular changes at protein, messenger ribonucleic acid (mRNA), and other molecular levels.

METHODS

We determined mRNA and protein levels of β 2 -microglobulin (β 2 -M) and nuclear factor κB (NF-κB) in tumors of different sizes using the real-time polymerase chain reaction and Western blotting, respectively. The relationship between these factors was verified in VS primary cells cultured in vitro, and the potential role of β 2 -M and NF-κB in VS growth was elucidated.

RESULTS

In the secretions of freshly isolated tumor tissue cultured for 72 h, the concentration of β 2 -M was positively correlated with the tumor diameter. Furthermore, tumors with larger diameter showed higher expressions of β 2 -M and NF-κB at protein and mRNA level. β 2 -M treatment resulted in elevated protein expression of NF-κB and also its phosphorylated form in vitro.

CONCLUSION

β 2 -M may participate in VS growth by regulating NF-κB and act as a key regulatory molecule in VS tumor growth.

Factors Influencing Personalized Management of Vestibular Schwannoma: A Systematic Review

Management of vestibular schwannoma (VS) is a complex process aimed at identifying a clinical indication for fractionated stereotactic radiotherapy (sRT) or microsurgical resection or wait and scan (WS). The aim of the review was to clarify which patient and tumor parameters may lead to different therapeutic choices, with a view to a personalized VS approach. A systematic review according to Preferred Reporting Items for Systematic Review and Meta-Analysis criteria was conducted between February and March 2022. The authors defined six parameters that seemed to influence decision-making in VS management: 1-incidental VS; 2-tumor size; 3-tumor regrowth after sRT; 4-subtotal resection; 5-patients' age; 6-symptoms. The initial search yielded 3532 articles, and finally, 812 articles were included. Through a qualitative synthesis of the included studies, management strategies were evaluated and discussed. An individualized proposal of procedures is preferable as compared to a single gold-standard approach in VS decision-making. The most significant factors that need to be considered when dealing with a VS diagnosis are age, tumor size and hearing preservation issues.

Prediction of postoperative recovery in patients with acoustic neuroma using machine learning and SMOTE-ENN techniques

Acoustic neuroma is a common benign tumor that is frequently associated with postoperative complications such as facial nerve dysfunction, which greatly affects the physical and mental health of patients. In this paper, clinical data of patients with acoustic neuroma treated with microsurgery by the same operator at Xiangya Hospital of Central South University from June 2018 to March 2020 are used as the study object. Machine learning and SMOTE-ENN techniques are used to accurately predict postoperative facial nerve function recovery, thus filling a gap in auxiliary diagnosis within the field of facial nerve treatment in acoustic neuroma. First, raw clinical data are processed and dependent variables are identified based on clinical context and data characteristics. Secondly, data balancing is corrected using the SMOTE-ENN technique. Finally, XGBoost is selected to construct a prediction model for patients' postoperative recovery, and is also compared with a total of four machine learning models, LR, SVM, CART, and RF. We find that XGBoost can most accurately predict the postoperative facial nerve function recovery, with a prediction accuracy of 90.0% and an AUC value of 0.90. CART, RF, and XGBoost can further select the more important preoperative indicators and provide therapeutic assistance to physicians, thereby improving the patient's postoperative recovery. The results show that machine learning and SMOTE-ENN techniques can handle complex clinical data and achieve accurate predictions.

Predicting surgical decision-making in vestibular schwannoma using tree-based machine learning

OBJECTIVE

Vestibular schwannomas (VSs) are the most common neoplasm of the cerebellopontine angle in adults. Though these lesions are generally slow growing, their growth patterns and associated symptoms can be unpredictable, which may complicate the decision to pursue conservative management versus active intervention. Additionally, surgical decision-making can be controversial because of limited high-quality evidence and multiple quality-of-life considerations. Machine learning (ML) is a powerful tool that utilizes data sets to essentialize multidimensional clinical processes. In this study, the authors trained multiple tree-based ML algorithms to predict the decision for active treatment versus MRI surveillance of VS in a single institutional cohort. In doing so, they sought to assess which preoperative variables carried the most weight in driving the decision for intervention and could be used to guide future surgical decision-making through an evidence-based approach.

METHODS

The authors reviewed the records of patients who had undergone evaluation by neurosurgery and otolaryngology with subsequent active treatment (resection or radiation) for unilateral VS in the period from 2009 to 2021, as well as those of patients who had been evaluated for VS and were managed conservatively throughout 2021. Clinical presentation, radiographic data, and management plans were abstracted from each patient record from the time of first evaluation until the last follow-up or surgery. Each encounter with the patient was treated as an instance involving a management decision that depended on demographics, symptoms, and tumor profile. Decision tree and random forest classifiers were trained and tested to predict the decision for treatment versus imaging surveillance on the basis of unseen data using an 80/20 pseudorandom split. Predictor variables were tuned to maximize performance based on lowest Gini impurity indices. Model performance was optimized using fivefold cross-validation.

RESULTS

One hundred twenty-four patients with 198 rendered decisions concerning management were included in the study. In the decision tree analysis, only a maximum tumor dimension threshold of 1.6 cm and progressive symptoms were required to predict the decision for treatment with 85% accuracy. Optimizing maximum dimension thresholds and including age at presentation boosted accuracy to 88%. Random forest analysis (n = 500 trees) predicted the decision for treatment with 80% accuracy. Factors with the highest variable importance based on multiple measures of importance, including mean minimal conditional depth and largest Gini impurity reduction, were maximum tumor dimension, age at presentation, Koos grade, and progressive symptoms at presentation.

CONCLUSIONS

Tree-based ML was used to predict which factors drive the decision for active treatment of VS with 80%–88% accuracy. The most important factors were maximum tumor dimension, age at presentation, Koos grade, and progressive symptoms. These results can assist in surgical decision-making and patient counseling. They also demonstrate the power of ML algorithms in extracting useful insights from limited data sets.

Treatment for vestibular schwannoma: Systematic review and single arm meta-analysis

OBJECTIVE

Vestibular schwannoma is a benign tumor in the schwannoma cells of the 8th cranial nerve. It causes symptoms like tinnitus, vertigo and end up with loss of hearing so the appropriate treatment is very important. There are many treatment techniques including conservative, surgery and radiosurgery. We aimed to systematically review and single arm meta-analysis the different treatment techniques of vestibular schwannoma.

METHODS

A comprehensive literature search using thirteen databases including PubMed, Scopus, and Web of Science was performed. All clinical trials about treatment vestibular schwannoma were included and single arm meta-analyzed. We assessed the risk of bias using ROBIN-I's tool and scale of Council Australia's Cancer Guidelines Wiki. The protocol was registered in PROSPERO (CRD42018089784) and has been updated on 17 April 2019.

RESULTS

A total of 35 clinical trials studies were included in the final analysis. The pooled proportion of stable hearing capability in patients receiving gamma knife radiosurgery (GKRS) was 64% (95% CI: 52%-74%). GKRS favored increased hearing capability 10% (95% CI: 7%-16%). Regarding tumor size, GKRS is the most protective method 53% (95% CI: 37%-69%). Complications occurred most commonly in single fractional linac stereotactic radiosurgery (SFSRT) 37% (95% CI: 12%-72%).

CONCLUSION

Our analysis suggested gamma knife radiosurgery could be the most ideal treatment for vestibular schwannoma based on stabilizing hearing capability, increasing hearing capability, decreasing tumor size and complications.

Long non-coding RNA BRCAT54 sponges microRNA-21 in vestibular schwannoma to suppress cell proliferation

BRCAT54 (also known as MRPS30 divergent transcript) is an anti-tumor long non-coding RNA (lncRNA) in lung cancer, while its role in vestibular schwannoma (VS) is unclear. We predicted that BRCAT54 could interact with microRNA (miR)-21, which suppresses VS cell proliferation. This study was then carried out to study the interaction between BRCAT54 and miR-21 in VS. A total of 56 VS samples and 42 normal vestibular nerve (VN) samples were included in this study. The expression of BRCAT54 and miR-21 in these samples were analyzed with RT-qPCR. Subcellular location of BRCAT54 in primary VS cells was analyzed by subcellular fractionation assay. The direct interaction between BRCAT54 and miR-21 was analyzed through RNA pull-down assay. Overexpression assay was performed to explore the interaction between BRCAT54 and miR-21. The role of BRCAT54 and miR-21 in primary VS cell proliferation was analyzed using BrdU assay. We found that BRCAT54 was downregulated in VS samples than that in VN samples, while miR-21 was upregulated in VS samples. BRCAT54 and miR-21 were not closely correlated. BRCAT54 was detected in both nuclear and cytoplasm samples, and BRCAT54 directly interacted with miR-21. However, BRCAT54 and miR-21 did not affect the expression of each other. BRCAT54 suppressed primary VS cell proliferation and inhibited the role of miR-21 in promoting cell proliferation. Therefore, BRCAT54 may sponge miR-21 to suppress cell proliferation in VS.

Automated objective surgical planning for lateral skull base tumors

PURPOSE

Surgical removal of pathology at the lateral skull base is challenging because of the proximity of critical anatomical structures which can lead to significant morbidity when damaged or traversed. Pre-operative computed surgical approach planning has the potential to aid in selection of the optimal approach to remove pathology and minimize complications.

METHODS

We propose an automated surgical approach planning algorithm to derive the optimal approach to vestibular schwannomas in the internal auditory canal for hearing preservation surgery. The algorithm selects between the middle cranial fossa and retrosigmoid approach by utilizing a unique segmentation of each patient's anatomy and a cost function to minimize potential surgical morbidity.

RESULTS

Patients who underwent hearing preservation surgery for vestibular schwannoma resection (n = 9) were included in the cohort. Middle cranial fossa surgery was performed in 5 patients, and retrosigmoid surgery was performed in 4. The algorithm favored the performed surgical approach in 6 of 9 patients.

CONCLUSION

We developed a method for computing morbidity costs of surgical paths to objectively analyze surgical approaches at the lateral skull base. Computed pre-operative planning may assist in surgical decision making, trainee education, and improving clinical outcomes.

Identification of key biomarkers and immune infiltration in sporadic vestibular schwannoma basing transcriptome-wide profiling

BACKGROUND

Vestibular schwannoma (VS) is a common intracranial tumor, with 95% of the cases being sporadic vestibular schwannoma (SVS). The purposed of this study was identifying genes responsible for inflammation in SVS and clarifying its underlying immune mechanisms.

METHODS

Transcriptional sequencing datasets (GSE141801 and GSE108237) from the Gene Expression Omnibus (GEO) database were used in this study. The candidate modules closely related to SVS and hub genes were screened out by weighted gene co-expression network analysis. Τhe sensitivity and specificity of the hub genes for SVS prediction were evaluated by ROC curve analysis. The CIBERSORT algorithm was subsequently applied to analyze the immune infiltration between SVS and controls. Finally, biological signaling pathways involved in the hub genes were identified via gene set enrichment analysis.

RESULTS

A total of 39 significantly enriched in myelination and collagen-containing extracellular matrix DEGs were identified at the screening step. Three hub genes (MAPK8IP1, SLC36A2, and OR2AT4) were identified, which mainly enriched in pathways of melanogenesis, GnRH, and calcium signaling pathways. Compared with normal nerves, SVS tissue contained a higher proportion of T cells, monocytes and activated dendritic cells, whereas proportions of M2 macrophages were lower.

CONCLUSIONS

The intergrated analysis revealed the pattern of immune cell infiltration in SVS and provided a crucial molecular foundation to enhance understanding of SVS. Hub genes MAPK8IP1, SLC36A2 and OR2AT4 are potential biomarkers and therapeutic targets to facilitate the accurate diagnosis, prognosis and therapy of SVS.

Neurofibromatosis type 2 versus sporadic vestibular schwannoma: The utility of MR diffusion and dynamic contrast-enhanced imaging

BACKGROUND AND PURPOSE

The goal of this study was to assess the utility of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to distinguish sporadic vestibular schwannomas (VSs) from those related to neurofibromatosis type 2 (NF2).

METHODS

We retrospectively reviewed 265 patients pathologically diagnosed with VSs between January 2015 and October 2020 in a single institution. There were 28 patients (male: 19, female: 9; age 11-67 years) including 23 sporadic and five NF2-related VSs, who had pretreatment DWI and DCE-MRI. Normalized mean apparent diffusion coefficient (nADCmean) and DCE-MRI parameters along with tumor characteristics were compared between sporadic and NF2-related VSs as appropriate. The diagnostic performances were calculated based on the receiver operating characteristic curve analysis for the values that showed significant differences. To identify significant modalities, multivariate logistic regression analysis was performed using nADCmean and the combination of statistically significant DCE-MRI parameters.

RESULTS

NADCmean, fractional volume of extracellular space (Ve), and forward volume transfer constant (Ktrans) were significantly different between sporadic and NF2-related VSs (nADCmean: median 1.62 vs. 1.16, P = .002; Ve: median 0.40 vs. 0.66, P = .007; Ktrans: median 0.17 vs. 0.33, P = .007), whereas fractional plasma volume (Vp), reverse reflux rate constant (Kep), and tumor characteristics were not. The diagnostic performances of nADCmean, Ve, and Ktrans were 0.93, 0.90, and 0.90 area under the curves with cutoffs of 1.46, 0.51, and 0.29, respectively. nADCmean and the combination of Ve and Ktrans were both chosen as significant differentiators by multivariate logistic regression analysis (P = .027).

CONCLUSIONS

DWI and DCE-MRI are both promising modalities to distinguish sporadic and NF2-related VSs.

Facial nerve sacrifice in lateral approaches to the skull base: Simultaneous reconstruction by graft interposition

PURPOSE

To evaluate the outcome of facial nerve (FN) cable graft interposition in lateral skull base surgery.

MATERIALS AND METHODS

A group of 16 patients who underwent FN graft interposition procedure was retrospectively considered. Postoperative FN function was evaluated using the House-Brackmann (HB) grading system, the Sunnybrook Facial Grading System (SFGS), the Facial Disability Index (FDI) and the Oral Functioning Scale (OFS) questionnaires.

RESULTS

56.2% of patients had a good postoperative FN outcome (HB grade II-III). Postoperative electromyography (EMG) showed re-innervation potentials in 60% of patients; median age of these patients was significantly lower compared to who did not manifest re-innervation (p = 0.039).

CONCLUSION

FN primary reconstruction remains the advisable rehabilitative option when the nerve is interrupted during lateral skull base surgeries, allowing to satisfactory postoperative results in more than half of patients. EMG confirmed the restoring of nerve conduction and it was more frequent in younger patients. The SFGS, the FDI and the OFS are important tools especially in the setting of a rehabilitation program.

Collagen Family Genes Associated with Risk of Recurrence after Radiation Therapy for Vestibular Schwannoma and Pan-Cancer Analysis

Background

The safety of radiotherapy techniques in the treatment of vestibular schwannoma (VS) shows a high rate of tumor control with few side effects. Neuropeptide Y (NPY) may have a potential relevance to the recurrence of VS. Further research is still needed on the key genes that determine the sensitivity of VS to radiation therapy.

Materials and Methods

Transcriptional microarray data and clinical information data from VS patients were downloaded from GSE141801, and vascular-related genes associated with recurrence after radiation therapy for VS were obtained by combining information from MSigDB. Logistics regression was applied to construct a column line graph prediction model for recurrence status after radiation therapy. Pan-cancer analysis was also performed to investigate the cooccurrence of these genes in tumorigenesis.

Results

We identified eight VS recurrence-related genes from the GSE141801 dataset. All of these genes were highly expressed in the VS recurrence samples. Four collagen family genes (COL5A1, COL3A1, COL4A1, and COL15A1) were further screened, and a model was constructed to predict the risk of recurrence of VS. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that these four collagen family genes play important roles in a variety of biological functions and cellular pathways. Pan-cancer analysis further revealed that the expression of these genes was significantly heterogeneous across immune phenotypes and significantly associated with immune infiltration. Finally, Neuropeptide Y (NPY) was found to be significantly and negatively correlated with the expression of COL5A1, COL3A1, and COL4A1.

Conclusions

Four collagen family genes have been identified as possible predictors of recurrence after radiation therapy for VS. Pan-cancer analysis reveals potential associations between the pathogenesis of VS and other tumorigenic factors. The relevance of NPY to VS was also revealed for the first time.

Potential Molecular Biomarkers of Vestibular Schwannoma Growth: Progress and Prospects

Vestibular schwannomas (VSs, also known as acoustic neuromas) are relatively rare benign brain tumors stem from the Schwann cells of the eighth cranial nerve. Tumor growth is the paramount factor for neurosurgeons to decide whether to choose aggressive treatment approach or careful follow-up with regular magnetic resonance imaging (MRI), as surgery and radiation can introduce significant trauma and affect neurological function, while tumor enlargement during long-term follow-up will compress the adjacent nerves and tissues, causing progressive hearing loss, tinnitus and vertigo. Recently, with the deepening research of VS biology, some proteins that regulate merlin conformation changes, inflammatory cytokines, miRNAs, tissue proteins and cerebrospinal fluid (CSF) components have been proposed to be closely related to tumor volume increase. In this review, we discuss advances in the study of biomarkers that associated with VS growth, providing a reference for exploring the growth course of VS and determining the optimal treatment strategy for each patient.

Facial pain and sensory outcomes following resection of tumors compressing the trigeminal nerve

OBJECTIVE

Tumors compressing the trigeminal nerve can cause facial pain, numbness, or paresthesias. Limited data exist describing how these symptoms change after resection and what factors predict symptom improvement. The objective of this study was to report trigeminal pain and sensory outcomes after tumor resection and identify factors predicting postoperative symptom improvement.

METHODS

This retrospective study included patients with tumors causing facial pain, numbness, or paresthesias who underwent resection. Trigeminal schwannomas were excluded. Logistic regression, recursive partitioning, and time-to-event analyses were used to report outcomes and identify variables associated with facial sensory outcomes.

RESULTS

Eighty-six patients met inclusion criteria, and the median follow-up was 3.1 years; 63 patients (73%) had meningiomas and 23 (27%) had vestibular schwannomas (VSs). Meningioma patients presented with pain, numbness, and paresthesias in 56%, 76%, and 25% of cases, respectively, compared with 9%, 91%, and 39%, respectively, for patients with VS. Most meningioma patients had symptoms for less than 1 year (60%), whereas the majority of VS patients had symptoms for 1-5 years (59%). The median meningioma and VS diameters were 3.0 and 3.4 cm, respectively. For patients with meningiomas, gross-total resection (GTR) was achieved in 27% of patients, near-total resection (NTR) in 29%, and subtotal resection (STR) in 44%. For patients with VS, GTR was achieved in 9%, NTR in 30%, and STR in 61%. Pain improved immediately after tumor resection in 81% of patients and in 92% of patients by 6 weeks. Paresthesias improved immediately in 80% of patients, increasing to 84% by 6 weeks. Numbness improved more slowly, with 52% of patients improving immediately, increasing to 79% by 2 years. Pain recurred in 22% of patients with meningiomas and 0% of patients with VSs. After resection, the Barrow Neurological Institute (BNI) facial pain intensity score improved in 73% of patients. The tumor diameter significantly predicted improvement in BNI score (OR 0.47/cm larger, 95% CI 0.22-0.99; p = 0.047). Complete decompression of the trigeminal nerve was associated with qualitative improvement in pain (p = 0.037) and decreased pain recurrence (OR 0.08, 95% CI 0.01-0.67; p = 0.024).

CONCLUSIONS

Most patients with facial sensory symptoms caused by meningiomas or VSs experienced improvement after resection. Surgery led to immediate and sustained improvement in pain and paresthesias, whereas numbness was slower to improve. Patients with smaller tumors and complete decompression of the trigeminal nerve were more likely to experience improvement in facial pain.

Prediction of blood supply in vestibular schwannomas using radiomics machine learning classifiers

This study attempts to explore the radiomics-based features of multi-parametric magnetic resonance imaging (MRI) and construct a machine-learning model to predict the blood supply in vestibular schwannoma preoperatively. By retrospectively collecting the preoperative MRI data of patients with vestibular schwannoma, patients were divided into poor and rich blood supply groups according to the intraoperative recording. Patients were divided into training and test cohorts (2:1), randomly. Stable features were retained by intra-group correlation coefficients (ICCs). Four feature selection methods and four classification methods were evaluated to construct favorable radiomics classifiers. The mean area under the curve (AUC) obtained in the test set for different combinations of feature selecting methods and classifiers was calculated separately to compare the performance of the models. Obtain and compare the best combination results with the performance of differentiation through visual observation in clinical diagnosis. 191 patients were included in this study. 3918 stable features were extracted from each patient. Least absolute shrinkage and selection operator (LASSO) and logistic regression model was selected as the optimal combinations after comparing the AUC calculated by models, which predicted the blood supply of vestibular schwannoma by K-Fold cross-validation method with a mean AUC = 0.88 and F1-score = 0.83. Radiomics machine-learning classifiers can accurately predict the blood supply of vestibular schwannoma by preoperative MRI data.

Decision making on vestibular schwannoma treatment: predictions based on machine-learning analysis

Decision making on the treatment of vestibular schwannoma (VS) is mainly based on the symptoms, tumor size, patient's preference, and experience of the medical team. Here we provide objective tools to support the decision process by answering two questions: can a single checkup predict the need of active treatment?, and which attributes of VS development are important in decision making on active treatment? Using a machine-learning analysis of medical records of 93 patients, the objectives were addressed using two classification tasks: a time-independent case-based reasoning (CBR), where each medical record was treated as independent, and a personalized dynamic analysis (PDA), during which we analyzed the individual development of each patient's state in time. Using the CBR method we found that Koos classification of tumor size, speech reception threshold, and pure tone audiometry, collectively predict the need for active treatment with approximately 90% accuracy; in the PDA task, only the increase of Koos classification and VS size were sufficient. Our results indicate that VS treatment may be reliably predicted using only a small set of basic parameters, even without the knowledge of individual development, which may help to simplify VS treatment strategies, reduce the number of examinations, and increase cause effectiveness.

Breaking a dogma: acute anti-inflammatory treatment alters both post-lesional functional recovery and endogenous adaptive plasticity mechanisms in a rodent model of acute peripheral vestibulopathy

BACKGROUND

Due to their anti-inflammatory action, corticosteroids are the reference treatment for brain injuries and many inflammatory diseases. However, the benefits of acute corticotherapy are now being questioned, particularly in the case of acute peripheral vestibulopathies (APV), characterized by a vestibular syndrome composed of sustained spinning vertigo, spontaneous ocular nystagmus and oscillopsia, perceptual-cognitive, posturo-locomotor, and vegetative disorders. We assessed the effectiveness of acute corticotherapy, and the functional role of acute inflammation observed after sudden unilateral vestibular loss.

METHODS

We used the rodent model of unilateral vestibular neurectomy, mimicking the syndrome observed in patients with APV. We treated the animals during the acute phase of the vestibular syndrome, either with placebo or methylprednisolone, an anti-inflammatory corticosteroid. At the cellular level, impacts of methylprednisolone on endogenous plasticity mechanisms were assessed through analysis of cell proliferation and survival, glial reactions, neuron's membrane excitability, and stress marker. At the behavioral level, vestibular and posturo-locomotor functions' recovery were assessed with appropriate qualitative and quantitative evaluations.

RESULTS

We observed that acute treatment with methylprednisolone significantly decreases glial reactions, cell proliferation and survival. In addition, stress and excitability markers were significantly impacted by the treatment. Besides, vestibular syndrome's intensity was enhanced, and vestibular compensation delayed under acute methylprednisolone treatment.

CONCLUSIONS

We show here, for the first time, that acute anti-inflammatory treatment alters the expression of the adaptive plasticity mechanisms in the deafferented vestibular nuclei and generates enhanced and prolonged vestibular and postural deficits. These results strongly suggest a beneficial role for acute endogenous neuroinflammation in vestibular compensation. They open the way to a change in dogma for the treatment and therapeutic management of vestibular patients.

Evaluation of Vestibular Function in Diagnosis of Vestibular Schwannomas

Vestibular schwannomas (VS) are benign tumors of the vestibular nerve. The common first symptoms are hearing loss and tinnitus, followed by imbalance, vertigo, and facial nerve involvement. The subjective symptoms of VS patients are not consistent with the severity of vestibular lesions and the results of vestibular tests, which often interfere with clinicians' diagnoses. Thus, the main screening and diagnostic methods for VS are audiometry and magnetic resonance imaging (MRI), ignoring the evaluation of vestibular function at the source of pathological lesions. With the development and improvement of vestibular evaluation technology and its wide application in the clinic, modern vestibular examination technology can reflect the severity and frequency of vestibular lesions and compensation from multiple perspectives, providing an objective basis for the diagnosis and treatment of vestibular diseases. In this report, we review the results and characteristics of vestibular tests in VS patients and further clarify the clinical value of vestibular function assessment in the diagnosis and treatment of VS.

Detection of early changes in the post-radiosurgery vestibular schwannoma microenvironment using multinuclear MRI

Stereotactic radiosurgery (SRS) is an established, effective therapy against vestibular schwannoma (VS). The mechanisms of tumour response are, however, unknown and in this study we sought to evaluate changes in the irradiated VS tumour microenvironment through a multinuclear MRI approach. Five patients with growing sporadic VS underwent a multi-timepoint comprehensive MRI protocol, which included diffusion tensor imaging (DTI), dynamic contrast-enhanced (DCE) MRI and a spiral 23Na-MRI acquisition for total sodium concentration (TSC) quantification. Post-treatment voxelwise changes in TSC, DTI metrics and DCE-MRI derived microvascular biomarkers (Ktrans, ve and vp) were evaluated and compared against pre-treatment values. Changes in tumour TSC and microvascular parameters were observable as early as 2 weeks post-treatment, preceding changes in structural imaging. At 6 months post-treatment there were significant voxelwise increases in tumour TSC (p < 0.001) and mean diffusivity (p < 0.001, repeated-measures ANOVA) with marked decreases in tumour microvascular parameters (p < 0.001, repeated-measures ANOVA). This study presents the first in vivo evaluation of alterations in the VS tumour microenvironment following SRS, demonstrating that changes in tumour sodium homeostasis and microvascular parameters can be imaged as early as 2 weeks following treatment. Future studies should seek to investigate these clinically relevant MRI metrics as early biomarkers of SRS response.

Predictors of Postoperative Complications in Vestibular Schwannoma Surgery-A Population-Based Study

OBJECTIVE

To investigate preoperative patient demographics and comorbidities in relation with postsurgical complications following vestibular schwannoma surgery.

STUDY DESIGN

Retrospective population-based cohort study.

SETTING

All hospitals in the Canadian province of Ontario.

PATIENTS

This study includes 1,456 patients who underwent vestibular schwannoma surgery from April 1, 2002 to March 31, 2018 in Ontario, Canada.

INTERVENTION/OUTCOME MEASURES

For all surgical patients, the demographic data, preoperative comorbidities, and postoperative complications were evaluated. Postoperative complications were examined immediately following surgery in the hospital as well as 1 year following the hospital discharge.

RESULTS

The most common comorbidities in this cohort were hypertension (30.22%), diabetes (9.48%), asthma (13.53%), and chronic obstructive pulmonary disease (6.73%). Diabetes was the most impactful comorbidity and was associated with higher risk of myocardial infarction (RR = 4.58, p < 0.01), pneumonia (RR = 1.80, p = 0.02), dysphagia (RR = 1.58, p < 0.01), and meningitis (RR = 3.62, p < 0.01). Analysis of surgical approaches revealed that the translabyrinthine approach, compared with the open craniotomy approach, was negatively associated with postoperative complications including pneumonia (RR = 0.43, p < 0.01), urinary tract infection (RR = 0.55, p = 0.01), dysphagia (RR = 0.66, p < 0.01), and readmission (RR = 0.45, p < 0.01).

CONCLUSION

This study examines patient demographics, preoperative comorbidities, and postoperative complications in patients who have undergone vestibular schwannoma surgery. The results highlight associations between patient characteristics and postoperative outcomes that can aid in preoperative decision-making and counselling.

Precision Therapy for Brain Tumors in Hereditary Syndromes

OPINION STATEMENT

Nervous system tumors arising in the setting of monogenic, hereditary cancer predisposition syndromes are unique in that the initiating genetic event in tumor formation is known. This knowledge provides a powerful treatment approach if the alteration or pathway can be targeted with a therapeutic agent. A reasonable argument can be made for the use of targeted agents in these tumor patients, even though many of them have FDA approval only for other tumor types. It is our practice to use and employ targeted therapy when standard treatments have failed or represent an unattractive option. Over time, however, targeted therapies will likely become first-line options.

Skull Base Leiomyomas and Angioleiomyomas: A Systematic Literature Review and an Uncommon Case Report

BACKGROUND

Skull base leiomyomas (LMs) and angioleiomyomas (ALMs) are rare, and the understanding of this disease is limited. We present a systematic literature review of skull base LM and ALM and report a case of internal auditory canal (IAC) ALM.

METHODS

A systematic review was conducted following the PRISMA guidelines. PubMed and Embase were systematically queried for skull base LM and ALM, and Rayyan QCRI was used for the review. After applying exclusion criteria, individual articles were evaluated for quality control, data collection, and analysis. The presentation, management, and outcome of a 37-year-old man with a right-sided IAC ALM are described.

RESULTS

Of 68 unique entries, 27 studies were included. Thirty-four cases of skull base LM (n = 6) or ALM (n = 28) were identified. Average age at presentation was 45.1 ± 14.5 years, and 52.9% of patients were male. Tumor diameter was 2.75 ± 1.6 cm, with headaches being the most reported symptom. Commonly reported locations were the cavernous sinus and the external auditory canal. Only 3 cases of IAC ALM met the criteria for this review. All tumors were treated with surgery, and gross total resection was achieved in 27 patients. Radiation was given in 3 cases with subtotal resection.

CONCLUSIONS

Skull base LM and ALM are rare. Given the need for pathology, surgery has been the standard treatment for symptomatic skull base LM and ALM. It is important to understand the available data about this disease and consider it in the differential of skull base lesions.

Rare primary malignant peripheral nerve sheath tumor of the left testis: A case report

Malignant peripheral nerve sheath tumor (MPNST) is a rare disease. The present study discusses the case of a 30-year-old male patient who presented with complaints of pain in the left testis and groin over 1 month. Ultrasonography and computed tomography (CT) imaging revealed the presence of a space-occupying lesion localized in the left testis. The mass was completely resected using an open surgical approach and was diagnosed as a primary MPNST of the left testis on postoperative histopathological examination. As this type of tumor is rare, there is currently no standard diagnostic or treatment method for MPNST. Pathological examination, enhanced CT imaging and immunohistochemical investigation are helpful for establishing the diagnosis and surgical resection is considered to be an effective treatment.

Bilateral Vestibular Schwannomas in a Patient with Ring Chromosome 22: Case Report and Review of the Literature

INTRODUCTION

Ring chromosome 22 (r[22]) can lead to the development of intracranial tumors such as meningiomas, neurofibromas, and schwannomas similar to neurofibromatosis 2 (NF2).

CASE PRESENTATION

An 18-year-old female with r(22) and a history of global development delay and cognitive impairment presented with sudden hearing loss. MRI revealed bilateral vestibular schwannomas. Given documented audiologic decline in the patient's hearing, the larger tumor was treated with CyberKnife fractionated stereotactic radiosurgery, and the smaller tumor is being monitored.

CONCLUSION

This case provides further evidence that patients with r(22) can develop clinical features of NF2, including the development of bilateral vestibular schwannomas, and should be monitored for hearing disturbances starting in puberty as a warning sign for these tumors.

Reduced grey- and white matter volumes due to unilateral hearing loss following treatment for vestibular schwannoma

Objective

Previous studies of the consequences of unilateral hearing loss (UHL) on the functional-structural organization of the brain has included subjects with various degrees of UHL. We suggest that the consequences of a total loss of hearing in one ear might differ from those seen in subjects with residual hearing in the affected ear. Thus, the main aim of the present study was to compare the structural properties of auditory and non-auditory brain regions in persons with complete UHL to those of normal hearing controls. We hypothesize that the consequences of complete UHL following treatment for vestibular schwannoma will differ between ipsi- and contralateral structures, as well as between right- and left side deafness.

Design

A 3T Siemens Prisma MR-scanner was used. Anatomical images were acquired using a high-resolution T1-weighted sequence. Grey- and white matter volumes were assessed using voxel-based morphometry.

Study sample

Twenty-two patients with left- or right-side unilateral hearing loss. Fifty normal hearing controls.

Results

Reductions in grey- and white matter volumes were seen in cortical and sub-cortical regions, mainly in the right hemisphere including the auditory cortex, lingual gyrus, cuneus, middle temporal gyrus, occipital fusiform gyrus, middle cingulate gyrus and the superior temporal gyrus. Patients displayed reduced grey- and white matter volumes in cerebellar exterior structures ipsilateral to the tumor side.

Conclusion

When compared to controls, right side hearing loss yields more widespread reduction of grey matter volume than left side hearing loss. The findings of reduced grey- and white matter volumes in auditory and non-auditory brain regions could be related to problems with speech perception in adverse listening conditions, increased listening effort and reduced quality of life reported by persons with unilateral hearing loss despite normal hearing in the unaffected ear.