Management of Vestibular Schwannomas

1. What is the decision or change you are facing or struggling with where a summary of the evidence would be helpful?

The authors want to assess the clinically relevant evidence for management of vestibular schwannomas that has been published since the guidelines they wrote and published in 2017. The evidence used for that guideline utilized data published through 2014. Fortunately, new research is has been published on this topic, and these guidelines are meant to be improved upon as this new evidence matures and is published. With the new data available since 2014, the authors will develop an updated guideline based on a new systematic review of the literature published on this topic 1/12015 through the present.

2. Why are you struggling with this issue?

Vestibular schwannomas account for 8% of all intracranial tumors. Vestibular schwannomas are considered “rare”, however Marinelli et al reported more than 1 case per 500 people. Clinical management remains controversial with substantial variation across the nation and globally. Better access to imaging has yielded and increase in reported incidence of vestibular schwannomas, and management strategies increasingly prioritize the preservation of neurologic function. There are several treatment options in terms of simple observation by imaging alone, surgical approaches and radiation techniques and patient preference continues toinfluencedecision-making.

This systematic review would help inform the clinical practice guideline update by allowing the authors synthesize new evidence on this topic to help provide better information for decision-making by providers and their patients.

3. What do you want to see changed? How will you know that your issue is improving or has been addressed?

We would like to update the recommendations we have provided for the following questions related to this topic:

Otologic and Audiologic Screening for Patients with Vestibular Schwannomas
Question 1: What is the expected diagnostic yield for vestibular schwannomas when using an MRI to evaluate patients with previously published definitions of asymmetric sensorineural hearing loss?
Question 2: What is the expected diagnostic yield for vestibular schwannomas when using an MRI to evaluate patients with asymmetric tinnitus, as defined as either purely unilateral tinnitus or bilateral tinnitus with subjective asymmetry?
Question 3: What is the expected diagnostic yield for vestibular schwannomas when using an MRI to evaluate patients with a sudden sensorineural hearing loss?

Hearing Preservation Outcomes in Patients with Sporadic Vestibular Schwannomas
Question 1: What is the overall probability of maintaining serviceable hearing following
single-fraction radiation therapy, utilizing modern dose planning, at two
years, five years, and ten years following treatment?
Question 2: Among patients with AAO-HNS class A or GR grade I hearing at baseline, what is the overall probability of maintaining serviceable hearing following single-fraction radiation therapy, utilizing modern dose planning, at two years, five years, and ten years following treatment?
Question 3: What patient- and tumor-related factors influence progression to non-serviceable hearing following single-fraction stereotactic radiation treatment using ≤ 13 Gy to the tumor margin?

Intraoperative Cranial Nerve Monitoring in Vestibular Schwannoma Surgery Facial Nerve Monitoring
Question 1: Does intraoperative facial nerve monitoring during vestibular schwannoma surgery lead to better long-term facial nerve function?
Question 2: Can intraoperative facial nerve monitoring be used to accurately predict
favorable long-term facial nerve function after vestibular schwannoma surgery?
Question 3: Does an anatomically intact facial nerve with poor electromyogram electrical responses during intraoperative testing reliably predict poor long-term facial nerve function?
Cochlear Nerve Monitoring
Question 4: Should intraoperative eighth cranial nerve monitoring be used during
vestibular schwannoma surgery?
Question 5: Is direct monitoring of the eighth cranial nerve superior to the use of
far-field auditory brain stem responses?

The Role of Imaging in the Diagnosis and Management of Patients with Vestibular Schwannomas
Question 1: What sequences should be obtained on MRI to evaluate vestibular schwannomas
before and after surgery?
Question 2: Is there a role for advanced imaging for facial nerve detection preoperatively (eg, CISS/FIESTA or DTI imaging)?
Question 3: What is the expected growth rate of vestibular schwannomas on MRI, and how often should they be imaged if a “watch and wait” philosophy is pursued?
Question 4: Do cystic vestibular schwannomas behave differently than their solid counterparts?
Question 5: Should the extent of lateral internal auditory canal (IAC) involvement be considered by treating physicians?
Question 6: How should patients with neurofibromatosis type 2 (NF2) and vestibular schwannoma be imaged and over what follow-up period?
Question 7: How long should vestibular schwannomas be imaged after surgery, including after gross total, near total, and subtotal resection?

Pathologic Methods and Prognostic Factors in Vestibular Schwannomas
Question 1: What is the prognostic significance of Antoni A versus B histologic patterns in VSs?
Question 2: What is the prognostic significance of mitotic figures seen in vestibular schwannoma specimens?
Question 3: Are there other light microscopic features that predict clinical behavior of vestibular schwannomas?
Question 4: Does the KI-67 labeling index predict clinical behavior of vestibular schwannomas?
Question 5: Does the proliferating cell nuclear antigen labeling index predict clinical behavior of vestibular schwannomas?
Question 6: Does degree of vascular endothelial growth factor expression predict clinical behavior of vestibular schwannomas?

Surgical Resection for the Treatment of Patients with Vestibular Schwannomas
Question 1: What surgical approaches for vestibular schwannomas (VS) are best for complete resection and facial nerve (FN) preservation when serviceable hearing is present?
Question 2: Which surgical approach (RS or translabyrinthine [TL]) for VSs is best for complete resection and FN preservation when serviceable hearing is not present?
Question 3: Does VS size matter for facial and vestibulocochlear nerve preservation with surgical resection?
Question 4: Should small intracanalicular tumors (< 1.5 cm) be surgically resected?
Question 5: Is hearing preservation routinely possible with VS surgical resection when serviceable hearing is present?
Question 6: When should surgical resection be the initial treatment in patients with NF2?
Question 7: Does a multidisciplinary team, consisting of neurosurgery and neurotology, provide the best outcomes of complete resection and facial/vestibulocochlear nerve preservation for patients undergoing resection of VSs?
Question 8: Does a subtotal surgical resection of a VS followed by stereotactic radiosurgery (SRS) to the residual tumor provide comparable hearing and FN preservation to patients who undergo a complete surgical resection?
Question 9: Does surgical resection of VSs treat preoperative balance problems more effectively than SRS?
Question 10: Does surgical resection of VSs treat preoperative trigeminal neuralgia more effectively than SRS?
Question 11: Is surgical resection of VSs more difficult (associated with higher facial neuropathies and subtotal resection rates) after initial treatment with SRS?

Emerging Therapies for the Treatment of Patients with Vestibular Schwannomas
Medical Therapy
Question: What is the role of bevacizumab in the treatment of patients with vestibular schwannomas (VSs)?
Question: Is there a role for lapatinib, erlotinib, or everolimus in the treatment of patients with VSs?
Question: What is the role of aspirin, to augment inflammatory response, in the treatment of patients with VSs?
Question: Is there a role for treatment of vasospasm, ie, nimodipine or hydroxyethyl starch, perioperatively to improve facial nerve outcomes in patients with VSs?
Prehabilitation
Question: Is there a role for preoperative vestibular rehab or vestibular ablation with gentamicin for patients surgically treated for VSs?
Surgical Therapy
Question: Does endoscopic assistance make a difference in resection or outcomes in patients with VSs?

4. When do you need the evidence report?

Fri, 04/15/2022

5. What will you do with the evidence report?

The purpose of this topic nomination is to obtain new evidence published on the clinical management of vestibular schwannomas since 1/1/2015, from which, the Congress of Neurological Surgeons (CNS) will develop a guideline update to serve as a resource for clinicians by determining the best options for the Management of Patients with Vestibular Schwannomas.

The CNS maintains in-house infrastructure to lead, promote, and support the creation and methodological processes to produce evidence-based guidelines, which are critical tools to confront a rapidly changing health care environment. Using the CNS’s high quality, rigorous methodological process, a multidisciplinary task force will develop recommendations based on the available evidence provided by the Evidence Based Practice Center. Throughout development, the task force will use evidence-based methodologies and strictly adhere to a priori defined criteria as defined by the National Academy of Medicine (formerly the Institute of Medicine’s [IOM)]) standards for conducting systematic reviews and clinical evidence-based guidelines.

This topic was initiated by the Section on Tumors of the American Academy of Neurological Surgeons (AANS)/CNS. The CNS also recruited experts from a variety of institutions and subspecialty disciplines in an effort to have as broad a representation of opinions and expertise as possible, including representatives from radiology, otolaryngology, audiometry, radiation oncology and neurosurgery. It is CNS’s goal to follow the IOM recommendations to be inclusive and inter-disciplinary when constructing our guidelines and subsequent recommendations. A conscientious effort will also be made to be sure that any conflict of interest is fully disclosed and avoided. Participants who have published extensively in certain areas will be asked to recuse themselves from writing on those areas and will be assigned to evaluate evidence in other topics. Every effort will be made to ensure that the guideline is accurate, reliable, and non-biased.

The CNS guidelines attempt to provide essential information for clinicians, globally, helping to improve patient care and outcomes. In addition to developing high quality guidelines, CNS is also committed to dissemination of guidelines in multiple, open access formats, such as publication in peer-reviewed journals, publication on the CNS webpage, webinars, conference seminars and courses, as well as other promotional efforts.

(Optional) About You

What is your role or perspective? Professional Society

If you are you making a suggestion on behalf of an organization, please state the name of the organization: Congress of Neurological Surgeons

May we contact you if we have questions about your nomination? Yes