Intracanalicular Vestibular Schwannoma Research Articles

Stereotactic radiosurgery for benign brain tumors: Results of multicenter benchmark planning studies

PurposeStereotactic radiosurgery (SRS) is strongly indicated for treatment of surgically inaccessible benign brain tumors. Various treatment platforms are available, but few comparisons have included multiple centers. As part of a national commissioning program, benchmark planning cases were completed by all clinical centers in the region. Methods and materialsFour benign cases were provided, with images and structures predelineated, including intracanalicular vestibular schwannoma (VS), larger VS, skull base meningioma, and secreting pituitary adenoma. Centers were asked to follow their local practice, and plans were reviewed centrally using metrics for target coverage, selectivity, gradient falloff, and normal tissue sparing. ResultsSixty-eight plans were submitted using 18 different treatment platforms. Fourteen plans were subsequently revised following feedback, and review of 5 plans led to a restriction of service on 2 platforms (2 centers). Prescription doses were consistent for VS and meningioma submissions, but a wide range of doses were used for the pituitary case. All centers prioritized coverage, with the prescription isodose covering ≥95% of 78/82 target volumes. Lower values may be expected next to air cavities when using advanced algorithms, and in general may be acceptable for some benign lesions. Selectivity was much more variable, and in some cases this was combined with high gradient index and/or >1 mm margin, resulting in large volumes of normal tissue being irradiated. Normal tissue doses were more variable across linear accelerator (LINAC)-based plans than with Gamma Knife or CyberKnife, and dose spillage seemed independent of prescription isodose (inhomogeneity). This may reflect the variety of LINAC-based approaches represented or the necessary tradeoff between different objectives. ConclusionsThese benchmarking exercises have highlighted areas of different clinical practice and priorities and potential for improvement. The subsequent sharing of plan data and margin philosophies between the neurosurgery and oncology communities allowed for meaningful comparison between centers and their peers.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Role of Radiosurgery and Radiation Therapy in the Management of Patients With Vestibular Schwannomas.

What are the indications for stereotactic radiosurgery (SRS) treatment vs observation for patients with intracanalicular vestibular schwannomas without evidence of radiographic progression? Level 3: If tinnitus is not observed at presentation, it is recommended that intracanalicular vestibular schwannomas and small tumors (<2 cm) without tinnitus be observed as observation does not have a negative impact on tumor growth or hearing preservation compared to treatment. Is there a difference in outcome based on radiosurgery equipment used: Gamma Knife (Elekta, Stockholm, Sweden) vs linear accelerator-based radiosurgery vs proton beam? There are no studies that compare 2 or all 3 modalities. Thus, recommendations on outcome based on modality cannot be made. Is there a difference in outcome based on the dose delivered? Level 3: As there is no difference in radiographic control using different doses, it is recommended that for single fraction SRS doses, <13 Gy be used to facilitate hearing preservation and minimize new onset or worsening of preexisting cranial nerve deficits. Is there a difference in outcome based on the number of fractions? As there is no difference in radiographic control and clinical outcome using single or multiple fractions, no recommendations can be given. What is the best time sequence for follow-up images after SRS? Level 3: Follow-up imaging should be obtained at intervals after SRS based on clinical indications, a patient's personal circumstances, or institutional protocols. Long-term follow-up with serial magnetic resonance imagings to evaluate for recurrence is recommended. No recommendations can be given regarding the interval of these studies. Is there a role for retreatment? Level 3: When there has been progression of tumor after SRS, SRS can be safely and effectively performed as a retreatment. What is the risk of radiation-induced malignant transformation of vestibular schwannomas treated with SRS? Level 3: Patients should be informed that there is minimal risk of malignant transformation of vestibular schwannomas after SRS. What are the indications for SRS in patients with neurofibromatosis type 2? Level 3: Radiosurgery is a treatment option for patients with neurofibromatosis type 2 whose vestibular schwannomas are enlarging and/or causing hearing loss. The full guideline can be found at: https://www.cns.org/guidelines/guidelines-management-patients-vestibular-schwannoma/chapter_7.

The outcomes and techniques of resection of intracanalicular vestibular schwannomas through middle fossa approach

Objective To investigate the surgical outcomes and techniques of middle fossa (MF) approach for resection of intracanalicular vestibular schwannomas. Methods Ten patients diagnosed with intracanalicular vestibular schwannoma underwent surgery treatment through MF approach at Department of Neurosurgery, Tangdu Hospital, Airforce Military Medical University from January 2012 to December 2015. The effects of surgery on hearing and facial nerve functions were assessed according to American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) classification and House-Brackmann (H-B) grading system, respectively. Results All patients achieved complete resection of tumor. Intracranial infection occurred in 1 case. There was no death or cerebrospinal fluid (CSF) leakage. The MRI results at 6-12 months post surgery suggested no recurrence of tumor. The rate of postoperative effective hearing (class A/B) preservation was 4/5, and the rate of functional facial nerve (class Ⅰ/Ⅱ) preservation rate was 9/10. Conclusions For intracanalicular vestibular schwannomas, microsurgery via the MF approach could offer good preservation of hearing and facial nerve functions. Being familiar with the anatomy and techniques of MF approach would help to reduce the operative complications. Key words: Neuroma, acoustic; Neurosurgical procedures; Internal acoustic canal; Middle fossa approach; Hearing preservation

Intracanalicular Vestibular Schwannomas: Initial Clinical Manifestation, Imaging Classification, and Risk Stratification for Management Proposal.

There is no consensus about the use of observation as a therapeutic modality for intracanalicular vestibular schwannoma (ICVS). The objective of this study was to describe tumor evolution, its correlation with initial size, stage of vestibular schwannoma, clinical presentation and to propose a risk classification for tumor growth with a therapeutic decision algorithm. Fifty-three patients with ICVS were followed prospectively from 2010 to 2015. The mean follow-up was 32 months. Patients underwent clinical examination, audiogram, magnetic resonance imaging at 6, 12, and then 12 months intervals within the first 5 years of initial diagnosis. We analyzed the patient's clinical course, audiologic changes, initial tumor location, and correlation of different parameters with ICVS growth. Fourteen patients (26%) deteriorated their hearing level and 17 patients (27%) showed tumor growth during the follow-up period. Growth was noted during the first year of observation in 13 patients (76.5%). Considering initial presentation: tumor size, intracanalicular staging, and hearing level, patients with larger vestibular schwannoma, extension to the fundus regardless of tumor size, higher initial pure-tone average, and speech recognition test showed a significantly higher rate of tumor growth. ICVS evolution was not correlated with hearing deterioration with time. We should consider observation a therapeutic modality. We valid the intrameatal staging as prognostic factor and propose a stratification of patients into low, moderate, or high risk for potential tumor growth to guide the initial management of ICVS.

Middle fossa approach for resection of vestibular schwannoma.

Surgical approaches for removal of vestibular schwannoma are done through retrosigmoid, translabyrinthine, or middle fossa approaches, depending on the tumor size, preoperative hearing status, surgical team experience, and patient preference. The middle fossa approach (MFA) for the vestibular schwannoma (VS) route preserves hearing and can be done with minimal morbidity and mortality. The authors discuss the surgical anatomy of the middle fossa, internal auditory canal localization techniques, MFA indications and the procedure for VS removal, and outcome. Unlike otolaryngologists, who use the MFA to treat various pathological processes that involve the inner or middle ear, many neurosurgeons are unfamiliar with the MFA. Nevertheless, learning the technical nuances of the MFA adds to the neurosurgeon's armamentarium, especially for treatment of small intracanalicular VSs in young patients who wish to preserve hearing.

Endoscopic assistance in retrosigmoid transmeatal approach to intracanalicular vestibular schwannomas – An alternative for middle fossa approach. Technical note

BackgroundComplete surgical removal of intracanalicular vestibular schwannomas with nerve VII and VIII sparing and without worsening patient's status is challenging. Also the choice of an optimal surgical technique, which is usually limited to selection between retrosigmoid transmeatal (RT) and middle fossa (MF) approach, can be a challenge. Although many previous studies documented superiority of RT to MF approach and vice versa, still no consensus has been reached regarding an optimal approach to intracanalicular vestibular schwannomas. In this technical note, we present RT approach with an endoscopic assistance and highlight its advantages over MF approach in surgical management of pure intracanalicular vestibular schwannomas. MethodRT approach with an endoscopic assistance is presented as an optimal surgical treatment for intracanalicular vestibular schwannomas, and its advantages are compared to those offered by MF approach. ResultsUnder an endoscopic guidance, we found a residual tumor in the fundus of the inner acoustic canal and performed its gross total resection. ConclusionsRT approach is an excellent technique suitable for safe radical surgical treatment of T1 vestibular schwannomas; this technique is associated with lower morbidity risk than MF approach.

Ten-Year Follow-up on Tumor Growth and Hearing in Patients Observed With an Intracanalicular Vestibular Schwannoma.

Reports on the natural history of tumor growth and hearing in patients with a vestibular schwannoma (VS) are almost exclusively short-term data. Long-term data are needed for comparison with results of surgery and radiotherapy. To report the long-term occurrence of tumor growth and hearing loss in 156 patients diagnosed with an intracanalicular VS and managed conservatively. In this longitudinal cohort study, diagnostic and follow-up magnetic resonance imaging and audiometry were compared. After a follow-up of 9.5years, tumor growth had occurred in 37% and growth into the cerebellopontine angle had occurred in 23% of patients. Conservative treatment failed in 15%. The pure tone average had increased from 51- to 72-dB hearing level, and the speech discrimination score (SDS) had decreased from 60% to 34%. The number of patients with good hearing (SDS > 70%) was reduced from 52% to 22%, and the number of patients with American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) class A hearing was reduced from 19% to 3%. Hearing was preserved better in patients with 100% SDS at diagnosis than in patients with even a small loss of SDS. Serviceable hearing was preserved in 34% according to AAO-HNS (class A-B) and in 58% according to the word recognition score (class I-II). Rate of hearing loss was higher in patients with growing tumors. Tumor growth occurred in only a minority of patients diagnosed with an intracanalicular VS during 10years of observation. The risk of hearing loss is small in patients with normal discrimination at diagnosis. Serviceable hearing is preserved spontaneously in 34% according to AAO-HNS and in 58% according to the word recognition score.

Commentary: Ten-Year Follow-up on Tumor Growth and Hearing in Patients Observed With an Intracanalicular Vestibular Schwannoma.

Commentary: Ten-Year Follow-up on Tumor Growth and Hearing in Patients Observed With an Intracanalicular Vestibular Schwannoma.

Surgical outcomes of middle fossa approach in intracanalicular vestibular schwannoma

Conclusion: Middle fossa approach (MFA) shows a hearing preservation rate of 86% and facial nerve function was preserved with HB grade I or II in 93%. MFA is a good treatment option for intra-canalicular vestibular schwannomas when surgical excision is needed.Background: Surgical outcomes of vestibular schwannoma have progressively improved with the advancement of microsurgical instruments. MFA is known to have better chances to preserve hearing, while it has limited access to the posterior fossa, limitation of tumor size, and higher risk of post-operative facial nerve weakness.Objectives: To investigate surgical outcomes and clinical efficiency of MFA in vestibular schwannoma.Methods: A retrospective study was done in 14 patients who underwent MFA for vestibular schwannoma in Asan Medical Center.Results: The median age at diagnosis was 46.3 years. At initial presentation, 57% of the patients had vertigo, 43% hearing disturbance, and 64% tinnitus. The mean tumor size was 9.7 mm. The tumors were completely resected in 86% of the patients. Hearing was post-operatively preserved in 12 patients and two patients lost their hearing following surgery. Facial nerve function post-operatively remained unchanged in 12 patients (86%).

Efficacy of microsurgical tumor removal for treatment of patients with intracanalicular vestibular schwannoma presenting with disabling vestibular symptoms.

OBJECTIVE The aim of this study was to analyze the efficacy and risks of microsurgery via the hearing-preserving retrosigmoid approach in patients with intracanalicular vestibular schwannoma (VS) suffering from disabling vestibular symptoms, with special attention to vertigo. METHODS This is a retrospective analysis of 19 patients with intracanalicular VS and disabling vestibular dysfunction as the main or only symptom (Group A). All of the patients reported having had disabling vertigo attacks. Subjective evaluation of the impairment of patients was performed before surgery, 3 weeks after surgery, 3 months after surgery, and 1 year after surgery, using the Dizziness Handicap Inventory (DHI). The main outcome measures were improvement in quality of life as measured using the DHI, and general and functional outcomes, in particular facial function and hearing. Patient age, preoperative tumor size, preoperative DHI score, and preservation of the nontumorous vestibular nerve were tested using a multivariate regression analysis to determine factors affecting the postoperative DHI score. The Mann-Whitney U-test was used to compare the postoperative DHI score at 3 weeks, 3 months, and 1 year after surgery with a control group of 19 randomly selected patients with intracanalicular VSs, who presented without vestibular symptoms (Group B). The occurrence of early postoperative discrete vertigo attacks was also compared between groups. RESULTS The preoperative DHI score was ≥ 54 in all patients. All patients reported having had disabling rotational vertigo before surgery. The only significant factor to affect the DHI outcome 3 weeks and 3 months after surgery was the preoperative DHI score. The DHI outcome after 1 year was not affected by the preoperative DHI score. Compared with the control group, the DHI score at 3 weeks and 3 months after surgery was significantly worse. There was no significant difference between the groups after 1 year. Vertigo was improved in all patients and completely resolved after 1 year in 17 patients. CONCLUSIONS Disabling vestibular dysfunction that affects quality of life should be considered an indication for surgery, even in otherwise asymptomatic patients with intracanalicular VS. Surgical removal of the tumor is safe and very effective in regard to symptom relief. All patients had excellent facial nerve function within 1 year after surgery, with a very good chance of hearing preservation.

Diagnosis and treatment of cavernous hemangioma of the internal auditory canal.

Cavernous hemangioma of the internal auditory canal (IAC) is an extremely rare type of tumor, and only 50 cases have been reported in the literature prior to this study. The aim in this study was to describe the symptomatology, radiological features, and surgical outcomes for patients with cavernous hemangioma of the IAC and to discuss the diagnostic criteria and treatment strategy for the disease. The study included 6 patients with cavernous hemangioma of the IAC. All patients presented with sensorineural hearing loss and tinnitus, and 2 also suffered from vertigo. Five patients reported a history of facial symptoms with hemispasm or palsy: 3 had progressive facial weakness, 1 had a hemispasm, and 1 had a history of recovery from sudden facial paresis. All patients underwent CT and MRI to rule out intracanalicular vestibular schwannomas and facial nerve neuromas. Five patients had their tumors surgically removed, while 1 patient, who did not have facial problems, was followed up with a wait-and-scan approach. All patients had a presurgical diagnosis of cavernous hemangioma of the IAC, which was confirmed pathologically in the 5 patients who underwent surgical removal of the tumor. The translabyrinthine approach was used to remove the tumor in 4 patients, while the middle cranial fossa approach was used in the 1 patient who still had functional hearing. Tumors adhered to cranial nerves VII and/or VIII and were difficult to dissect from nerve sheaths during surgeries. Complete hearing loss occurred in all 5 patients. In 3 patients, the facial nerve could not be separated from the tumor, and primary end-to-end anastomosis was performed. Intact facial nerve preservation was achieved in 2 patients. Patients were followed up for at least 1 year after treatment, and MRI showed no evidence of tumor regrowth. All patients experienced some level of recovery in facial nerve function. Cavernous hemangioma of the IAC can be diagnosed preoperatively through analysis of clinical features and neuroimaging. Early surgical intervention may preserve the functional integrity of the facial nerve and provide a better outcome after nerve reconstruction. However, preservation of functional hearing may not be achieved, even with the retrosigmoid or middle cranial fossa approaches. The translabyrinthine approach seems to be the most appropriate approach overall, as the facial nerve can be easily located and reconstructed.

Enlargement of the Internal Auditory Canal and Hearing Preservation in the Middle Fossa Approach for Intracanalicular Vestibular Schwannomas

The middle fossa (MF) approach is one of the treatment options for patients with intracanalicular vestibular schwannomas. This study investigated whether enlargement of the internal auditory canal (IAC) represents a risk factor for hearing loss in the MF approach. Participants comprised 48 patients who underwent resection of intracanalicular vestibular schwannoma using the MF approach at Nagoya City University Hospital. In this retrospective case review, the shape of the IAC on the affected side was compared with the normal side by coronal reconstruction computed tomography images. A difference of > 1 mm was judged as IAC enlargement. Patients were classified into 4 groups: NE, no enlargement; SE, superior enlargement; IE, inferior enlargement; and BE, both superior and inferior enlargement. In addition, pure-tone average (PTA) and speech discrimination score (SDS) were estimated before and after surgery to evaluate hearing. Hearing preservation (PTA ≤ 50 dB; SDS ≥ 50%) was seen in 96% (21/22), 100% (3/3), 50% (8/16), and 29% (2/7) in the NE, SE, IE, and BE groups, respectively. A significant difference in hearing preservation was seen between cases without IE (NE and SE) and cases with IE (IE and BE) (P < 0.0001). IE of the IAC was identified as an independent risk factor for hearing loss by logistic regression analysis (odds ratio, 32.0; 95% confidence interval, 4.2-783.6). Enlargement of the IAC on coronal reconstruction computed tomography scan before surgery can predict hearing preservation using the MF approach. Patients without IE may represent good surgical candidates for the MF approach.

Facial Nerve and Hearing Outcomes after Middle Cranial Fossa Vestibular Schwannoma Surgery

Background: Decision making for patients with small, intracanalicular vestibular schwannomas (VS) remains challenging. These individuals frequently have significant residual hearing and limited other symptoms. For younger patients, surgery through a middle fossa craniotomy (MFC) approach offers a chance for long-term hearing preservation, even for laterally placed tumors, and potentially avoids the need for radiation therapy and/or lifetime surveillance. However, the middle fossa approach has been characterized as one where the facial nerve location and temporal lobe retraction can be problematic.

Long-term outcome of Gamma Knife radiosurgery in patients with tiny intracanalicular vestibular schwannomas detected by three-dimensional fast imaging employing steady-state acquisition magnetic resonance

ObjectiveTo evaluate the effectiveness and long-term outcome of Gamma Knife radiosurgery (GKRS) for tiny vestibular schwannomas (VSs) detected by three-dimensional fast imaging employing steady-state acquisition magnetic resonance (3D-FIESTA MR). Materials and methodsBetween January and December 2004, 3D-FIESTA MR of the brain was performed in patients who had physical health examinations at the Buddhist Tzu Chi General Hospital (Hualien, Taiwan). Tiny intracanalicular VSs (defined as a tumor volume < 0.5 cm2) was detected in 13 patients (8 women and 5 men). The mean age of the patients was 60 years (range, 45–84 years). Hearing function was graded using the Gardner–Robertson (GR) classification. Dose planning was performed on intraoperative stereotactic contrast-enhanced images using multiple 4-mm isocenters. The mean tumor volume was 0.098 cm2 (range, 0.013–0.4 cm2). The mean margin dose was 12.4 Gy (range, 11–14 Gy), and the isodose line was set at a mean of 53.8% (range, 50–70%). ResultsTwelve patients had GR Grade I or II hearing before GKRS, and GR I or II hearing was maintained in 11 patients. Facial and trigeminal nerve functions were preserved in all patients. The tumor control rate was 100% at a mean follow-up period of 9.8 ± 1.1 years (range, 76–126 months). One patient developed acute vertigo 1 day after GKRS, which subsided after short-term use of steroids and did not recur. ConclusionWith the application of 3D-FIESTA, tiny VSs can be detected early. Because low-dose (12–14 Gy) GKRS is safe and effective for long-term control of the growth of tumors with acceptable preservation rate of hearing function, it may be worthwhile to use 3D-FIESTA to detect tiny VSs and treat the patients using GKRS.

The Factors Associated With Tumor Stability Observed With Conservative Management of Intracanalicular Vestibular Schwannoma

Periodic observation with imaging is an acceptable option for patients with small vestibular schwannomas (VSs). The objective of this study was to evaluate the outcome of conservative management of intracanalicular VSs (ICVSs). We reviewed 31 patients who were followed up for more than 1 year among patients diagnosed as having VS limited to the internal auditory canal. The median follow-up period was 31 months (range, 12-84 mo). We analyzed the patients' clinical features, clinical courses, and audiologic changes. The most frequent initial presenting symptom in patients with ICVS was hearing loss, and one-half of the patients (8 of 16) had a history of sudden hearing loss. Seven patients (22.5%) showed tumor growth during the follow-up period. When we considered the initial tumor size in ICVS, the patients larger in size than the median showed a significantly higher rate of tumor growth. In terms of the initial hearing levels of ICVS according to the Consensus Meeting Guidelines, five patients were classified as Class A (normal hearing) and six patients were classified as Class B. Only one patient among patients with useful hearing (Classes A and B) showed tumor growth. The follow-up hearing levels of all Class A patients were preserved; however, all Class B patients deteriorated to Class C. Patients with ICVS showed favorable results with conservative management. Among them, patients with small tumors and normal hearing showed a good prognosis.

Small Vestibular Schwannomas Presenting with Facial Nerve Palsy

To describe the surgical management and convalescence of two patients presenting with severe facial nerve weakness associated with small intracanalicular vestibular schwannomas (VS). Retrospective review. Two adult female patients presenting with audiovestibular symptoms and subacute facial nerve paralysis (House-Brackmann Grade IV and V). In both cases, post-contrast T1-weighted magnetic resonance imaging revealed an enhancing lesion within the internal auditory canal without lateral extension beyond the fundus. Translabyrinthine exploration demonstrated vestibular nerve origin of tumor, extrinsic to the facial nerve, and frozen section pathology confirmed schwannoma. Gross total tumor resection with VIIth cranial nerve preservation and decompression of the labyrinthine segment of the facial nerve was performed. Both patients recovered full motor function between 6 and 8 months after surgery. Although rare, small VS may cause severe facial neuropathy, mimicking the presentation of facial nerve schwannomas and other less common pathologies. In the absence of labyrinthine extension on MRI, surgical exploration is the only reliable means of establishing a diagnosis. In the case of confirmed VS, early gross total resection with facial nerve preservation and labyrinthine segment decompression may afford full motor recovery-an outcome that cannot be achieved with facial nerve grafting.

The Medially Migrating Intracanalicular Vestibular Schwannoma: Can We Count on MR Imaging to Give Us an Accurate Estimate of the Lateral Extension of a Tumor?

The Medially Migrating Intracanalicular Vestibular Schwannoma: Can We Count on MR Imaging to Give Us an Accurate Estimate of the Lateral Extension of a Tumor?

Hearing Outcomes After Stereotactic Radiosurgery for Unilateral Intracanalicular Vestibular Schwannomas: Implication of Transient Volume Expansion

We evaluated the prognostic factors for hearing outcomes after stereotactic radiosurgery (SRS) for unilateral sporadic intracanalicular vestibular schwannomas (IC-VSs) as a clinical homogeneous group of VSs. Sixty consecutive patients with unilateral sporadic IC-VSs, defined as tumors in the internal acoustic canal, and serviceable hearing (Gardner-Roberson grade 1 or 2) were treated with SRS as an initial treatment. The mean tumor volume was 0.34±0.03 cm3 (range, 0.03-1.00 cm3), and the mean marginal dose was 12.2±0.1 Gy (range, 11.5-13.0 Gy). The median follow-up duration was 62 months (range, 36-141 months). The actuarial rates of serviceable hearing preservation were 70%, 63%, and 55% at 1, 2, and 5 years after SRS, respectively. In multivariate analysis, transient volume expansion of ≥20% from initial tumor size was a statistically significant risk factor for loss of serviceable hearing and hearing deterioration (increase of pure tone average≥20 dB) (odds ratio=7.638; 95% confidence interval, 2.317-25.181; P=.001 and odds ratio=3.507; 95% confidence interval, 1.228-10.018; P=.019, respectively). The cochlear radiation dose did not reach statistical significance. Transient volume expansion after SRS for VSs seems to be correlated with hearing deterioration when defined properly in a clinically homogeneous group of patients.

Impact of Fundal Extension on Hearing After Surgery for Vestibular Schwannomas

To compare hearing preservation after surgery for intracanalicular vestibular schwannomas with or without fundal extension. Retrospective chart review. Patients with intracanalicular tumors (≤ 10-m maximal dimension) undergoing retrosigmoid craniotomy between 2001 and 2010. Preoperative and postoperative audiograms, preoperative magnetic resonance imaging, and operative reports were reviewed. Preoperative and postoperative hearing (American Academy of Otolaryngology-Head and Neck Surgery classification). Complete data for 53 patients (27 female and 24 male subjects, sex was not recorded for 2 patients) meeting selection criteria was available. Fundal involvement was identified in 39 (73.6%) of the 53 patients. The remaining 14 patients did not have tumor with fundal extension (26.4%). Average tumor size for patients with fundal extension (+FE) was 6.9 ± 2.2 mm and without fundal extension (-FE) was 8.2 ± 1.9 mm (p = 0.05, Student's t test). Average preoperative speech discrimination score for the entire study was 90.5 ± 11.8 (n = 53). After retrosigmoid approach for tumor resection, 79% of patients (42/53) had preserved hearing defined as American Academy of Otolaryngology-Head and Neck Surgery class A, B, or C. Average postoperative speech discrimination score for these patients was 89.3 ± 12.1, and average postoperative pure-tone average was 35.9 ± 9.1%. Eighty-five percent (33/39) of +FE patients had preserved hearing (class A, B, or C). In contrast, 64% (9/14) of -FE patients had hearing preserved (class A, B, or C; Fisher's exact test, p = 0.034). Hearing preservation rate after retrosigmoid craniotomy for intracanalicular vestibular schwannomas may be superior for tumors with fundal extension compared with tumors that do not extend to the fundus.

Current strategies in management of intracanalicular vestibular schwannoma

The current practitioner is more often managing intracanalicular vestibular schwannomas than in the past, as improved imaging and heightened awareness leads to earlier diagnosis of these tumors. The role of observation, microsurgery, and radiation treatment in the management of intracanalicular tumors continues to evolve. The goal of this article is to evaluate and summarize recent literature pertaining to the management of intracanalicular vestibular schwannomas. Watchful waiting is an important management option for patients with minimal symptoms. The literature on the natural history of small vestibular schwannomas continues to expand, with particular emphasis on the expected hearing outcomes. Microsurgical techniques also focus on hearing preservation. Presence of fundal fluid and good or normal hearing preoperatively are positive predictors of hearing preservation after surgery. Long-term follow-up after radiation therapy for vestibular schwannomas continues to demonstrate excellent tumor control rates, although hearing preservation rates are modest. Multiple factors, including status of hearing, presence of vestibular symptoms, patient age, medical comorbidities, institutional outcomes, and patient preferences, help determine the management strategy for patients with an intracanalicular vestibular schwannoma.