Sex and age associations with vestibular schwannoma size and presenting symptoms

Functional Outcome and Balance Compensation in Patients with Unilateral Vestibular Schwannoma After Surgical Treatment-Short- and Medium-Term Observation

Objective: The aim was to evaluate vestibular function in patients with unilateral vestibular schwannoma before and in the short and medium term after surgical treatment to analyze vestibular compensation. The identification of the prognostic factors determining incomplete and slower balance recovery was assessed. Methods: Forty-five patients with unilateral vestibular schwannoma treated surgically through the middle cranial fossa and translabyrinthine approach were enrolled in this study. The data were collected in the period between April 2022 and August 2023. The clinical data, vestibular tests (video head impulse test, sensory organization test) and the dizziness handicap inventory (DHI) before and after surgery were evaluated. Results: One month after surgery, a temporary deterioration in the DHI results occurred (DHI total score before surgery 24.36 vs. one month after surgery 31.64); however, a significant increase was found only by analyzing the functional subscale (p = 0.0395) for the DHI functional, emotional and physical subscale results; in addition, the total score before and three months after the surgery did not differ significantly. No statistically significant differences between the preoperative sensory organization test and the test one month after the surgery were found, while a significant improvement in the vestibular parameters was observed three months after the surgery compared to the preoperative results (C5 0.0306, C6 0.0002, VEST 0.0294, COMP 0.0023). A negative correlation was found between the DHI total score and C5 (-0.3198, -0.3266), C6 (-0.3448, -0.46379), VEST (-0.3100, -0.3252) and COMP (-0.4018, -0.4854) one and three months after the surgery, respectively. A significant deterioration was found between the LSC gain results on the tumor side (p < 0.001) and on the healthy side before the surgery vs. one month afterwards (p = 0.0079) and before the surgery vs. three months afterwards (p = 0.0419). The middle cranial fossa or translabyrinthine approach had no influence on the postoperative results. Conclusions: In the postoperative period, vestibular compensation occurs spontaneously. The results show that the functional level deteriorates one month after surgery but then improves significantly three months after the surgery, which confirms that compensation occurs gradually. The DHI functional subscale results before surgery and three months afterwards did not differ significantly, which demonstrates that functional recovery after vestibular denervation should take place within that time. In the present study, no predictive factors for unsatisfactory functional postoperative outcomes were found.

Audiological Characteristics of Vestibular Schwannoma Patients With Normal Pure-Tone Audiometry

OBJECTIVE

To investigate the audiological characteristics of vestibular schwannoma (VS) patients with normal pure-tone audiometry (PTA) results.

STUDY DESIGN

A retrospective study.

SETTING

Forty-two VS patients with normal PTA results from October 2016 to October 2022 were included.

METHODS

Normal PTA was defined when the hearing threshold is ≤25 dB hearing loss (HL) in each test frequency and the PTA is ≤25 dB HL. Results of multiple audiological tests such as the auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), multiple auditory steady-state responses threshold (ASSR), and speech discrimination score were retrospectively reviewed. Demographic data of these patients were also been collected.

RESULTS

According to our results, the ABR and average ASSR threshold of the affected side were statistically significantly higher in VS patients with normal PTA. ABR waveforms on the affected side also showed more abnormalities. The DPOAE pass rates of the affected side were lower than the unaffected side while the amplitude and signal-to-noise ratio rate was also lower. In addition, we used magnetic resonance imaging 3-dimensional reconstruction images to measure the volume of tumors in these patients. We also found that higher ABR threshold means lager tumor size in patients with normal PTA.

CONCLUSION

VS patients with normal PTA result cannot be assumed to have no impairment of hearing function. ABR, DPOAE, and ASSR results showed the characteristic changes in the affect ear. ABR threshold has the highest sensitivity for hearing abnormalities and is strong relative with tumor size in patients with normal PTA.

Radiation-Associated Vestibular Schwannomas: Case Series and Literature Review

OBJECTIVES

Radiation treatment, particularly at a young age, creates theoretical risk for long-term adverse radiation effects, including the development of malignancy. The literature is sparse on radiation-induced vestibular schwannomas (VSs).

METHODS

A retrospective review was performed for cases of suspected radiation-induced VS at 2 high-volume centers. Only cases where radiation included coverage of the posterior fossa were included with those diagnosed within 3 years of radiation treatment being excluded. Patient and tumor characteristics were collected. A systematic literature review was also performed for any previously published series on radiation-induced VS.

RESULTS

Eight cases of radiation-induced VS were identified with a median follow-up 125 months (range 7-131). The median age at incident radiation was 15 years (range 2-46). The median age at VS diagnosis was 57 years (range 26-83) with median interval from radiation to diagnosis of 51-years (range 15-66). The median tumor size was 6 mm (range 3-21). Two patients underwent surgical resection. Lesions were described as soft and highly vascular, with medium to high adherence to the facial nerve. Five articles with a total of 52 patients were identified, median age at VS diagnosis was 42-years (range 23-73) with a median interval from radiation to diagnosis of 19 years (range 15-23).

CONCLUSIONS

The development of VS following radiation exposure appears rare and our understanding of the condition remains incomplete. Further studies are required to determine the best management of these patients and determine whether there is a causative relationship between radiation exposure and the development of VS.

Incidence and presentation of vestibular schwannoma: a 3-year cohort registry study

BACKGROUND

Vestibular schwannoma (VS) is the most common benign tumour arising in the lateral skull base. Reported incidence rates of VS vary across geographical locations and over time. There is scarce updated evidence over the past decade on the epidemiology and mode of presentation of VS.

OBJECTIVE

To describe the epidemiology and mode of presentation of VS in the East of England between 2013 and 2016.

METHODS

A retrospective epidemiological analysis of data from a national VS registry and electronic patient records was conducted, including all newly diagnosed adult patients in a UK tertiary referral centre, between April 1st, 2013, and March 31st, 2016.

RESULTS

There were 391 new cases identified resulting in an overall mean incidence of 2.2 VS cases per 100,000 person-year. The incidence rate for all patients in the <40 age group ranged between 0.3 and 0.7 per 100,000 person-year, increasing to a range of 5.7 to 6.1 per 100,000 person-year in the 60-69 age group. The top three combinations of symptoms on presentation per patient were hearing loss and tinnitus (97, 24.8%), hearing loss alone (79, 20.2%) and hearing loss, tinnitus, and balance symptoms (61, 15.6%). The median duration of symptoms was 12 months, with a wide range from 1.4 to 300 months. Age was negatively correlated with tumour size (r = -0.14 [-0.24 to -0.04], p=0.01) and positively correlated with symptom duration (r = 0.16 [0.03-0.29], p=0.02).

CONCLUSIONS

The incidence of vestibular schwannoma has increased compared to previous studies in the UK and is similar to incidence rates reported in other countries during the past decade. It peaks in the seventh decade of life, mainly because of an increase in the diagnosis of small tumours with a long duration of audio-vestibular symptoms in older patients, compared to earlier studies.

Vestibular Complaints Impact on the Long-Term Quality of Life of Vestibular Schwannoma Patients

OBJECTIVE

To analyze the effect of dizziness-related symptoms on the long-term quality of life (QoL) of patients with unilateral vestibular schwannoma.

METHODS

In this cross-sectional study, patients with a unilateral vestibular schwannoma diagnosed between 2004 and 2013 completed a disease-specific QoL questionnaire (Penn Acoustic Neuroma Quality of Life [PANQOL]) and the Dizziness Handicap Inventory (DHI) in 2020. Linear regression was performed to assess the correlation between QoL and the DHI total score, and the scores of the DHI functional, emotional, and physical subdomains. Potential confounders such as age, sex, tumor size at baseline, and treatment modality (active surveillance, surgery, or radiotherapy) were included in the model.

RESULTS

In total, 287 of 479 patients (59%) experienced dizziness with a median follow-up of 10 years. The DHI total score was significantly associated with the PANQOL total score. On average, we found a reduction of 0.7 points on the PANQOL for each additional point on the DHI. The DHI emotional subdomain was the most prominent determinant of poorer QoL. Each point on the DHI emotional subscale was associated with a reduction of 1.3 on the PANQOL score. Treatment modality did not have a clinically relevant effect on dizziness-related QoL.

CONCLUSIONS

Even mild dizziness can have a significant and clinically relevant effect on the QoL of patients with unilateral vestibular schwannoma in the long term. This holds true for all treatment modalities. Addressing the vestibular problems may improve QoL in vestibular schwannoma patients, and DHI subscale analysis may help tailor the optimal vestibular intervention.

Progression of Hearing Loss in Observed Non-Growing Vestibular Schwannoma

OBJECTIVE

To assess hearing outcomes in observed vestibular schwannoma (VS) with focus on non-growing tumors.

STUDY DESIGN

Retrospective review.

SETTING

Two tertiary neurotology centers.

PATIENTS AND INTERVENTIONS

Patients with sporadic VS undergoing at least 3 years' observation.

MAIN OUTCOME MEASURES

Changes in pure tone averages (PTA) and word recognition scores (WRS) normalized to the contralateral ear.

RESULTS

During the study period, 39 of 105 included patients (37.1%) had tumor growth. Patients with tumor growth had a mean normalized increase in PTA of 8.0 dB HL (p = 0.008) corresponding to a normalized average worsening of their PTA of 1.8 dB per year. Patients with non-growing tumors less than 5 mm in maximal dimension did not have significant ongoing normalized hearing loss (p > 0.05). Patients with non-growing tumors more than or equal to 5 mm had a mean normalized increase in PTA of 7.4 dB HL (p = 0.001) corresponding to an average of 2.0 dB HL per year, which was similar to the loss observed in growing tumors regardless of size (p > 0.05). Normalized decline in PTA of at least 5 dB HL was seen in 72% of patients with growing tumors, 53% of patients with nongrowing tumors more than or equal to 5 mm, and 38% of patients with non-growing tumors less than 5 mm.

CONCLUSIONS

A long-term analysis of hearing outcomes in observed vestibular schwannoma is presented. With observation, VS more than or equal to 5 mm is associated with continued hearing loss even without tumor growth, while non-growing tumors less than 5 mm are not associated with continuing hearing loss. These data inform expectations for observed VS for providers and patients.

Management of Sporadic Vestibular Schwannomas in Children—Volumetric Analysis and Clinical Outcome Assessment

Vestibular schwannomas (VS) usually manifest between the 5th and 8th decade of life. Most pediatric cases are associated with Neurofibromatosis type 2 and sporadic VS are rare in this age group. Few case series have been published. We report on our institutional series of sporadic VS in children. We included all cases between 2003 and 2021; 28 of 1635 patients harbored a sporadic VS and were younger than 21 years old. A retrospective review of clinical parameters and surgical data as well as outcomes was performed. All procedures were performed via a retrosigmoid approach. Preoperative imaging was assessed, and tumor volumetry was performed. Mean follow-up was 28 months, symptomatology was diverse. Most children and adolescents presented with hearing loss and tinnitus. All cases with multiple preoperative magnetic resonance imaging scans showed volumetric tumor growth between 1 and 18%/month (mean 8.9 ± 5.6%). Cystic tumor morphology and bone erosion was seen in larger tumors. Gross total resection was possible in 78% of patients and no recurrence was observed. All patients with subtotal resection showed tumor regrowth. Sporadic VS in children are rare and present with a high clinical variability. Surgical resection is the primary therapy and is feasible with favorable results comparable to the adult age group.

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.

Impact of Treatment on Vestibular Schwannoma-Associated Symptoms: A Prospective Study Comparing Treatment Modalities

OBJECTIVE

The degree to which various treatment modalities modify vestibular schwannoma (VS)-associated symptoms has received limited attention. The purpose of this study was to determine how different treatment modalities affect subjective symptoms in those presenting with VS.

STUDY DESIGN

Prospective survey.

SETTING

Tertiary neurotology referral center.

METHODS

Patients with sporadic VS who received treatment at our institution were prospectively surveyed with a VS symptom questionnaire. Those who completed a baseline survey prior to treatment and at least 1 posttreatment survey were included. The prospective survey evaluated the severity of self-reported symptoms (Likert scale, 1-10), including tinnitus, dizziness or imbalance, headaches, and hearing loss.

RESULTS

A total of 244 patients were included (mean age, 57 years). The mean duration of follow-up was 2.1 years, and the median number of surveys completed was 2 (interquartile range, 1-3). Seventy-eight (32%) cases were managed with observation, 118 (48%) with microsurgery, and 48 (20%) with radiosurgery. Multivariable analyses revealed no statistically significant difference in the change in tinnitus (P = .15), dizziness or imbalance (P = 0.66), or headaches (P = .24) among treatment groups. Evaluation of clinically important differences demonstrated that microsurgery leads to significant bidirectional changes in headaches.

CONCLUSIONS

Limited prospective data exist regarding the progression or resolution of subjective symptoms in those presenting with VS. This study suggests that tinnitus, dizziness or imbalance, and headaches are unlikely to be significantly modified by treatment modality and generally should not be used to direct treatment choice.

Association between socioeconomic indicators and geographic distribution of vestibular schwannomas in West Scotland: a 15-year review

OBJECTIVE

Socioeconomic risk factors may contribute to geographic variation in diseases, but studies are limited due to lack of large available cohorts.

METHOD

A geographic analysis was performed of the association between socioeconomic risk factors and the distribution of vestibular schwannomas in adults diagnosed with sporadic vestibular schwannomas through the National Health Services in the West of Scotland from 2000 to 2015.

RESULTS

A total of 511 sporadic vestibular schwannomas were identified in a population of over 3.1 million. Prevalence of vestibular schwannomas were lowest in cases with good health (-0.64, 95 per cent confidence interval: -0.93,-0.38; p = 0.002) and level 1 qualifications (-0.562, 95 per cent confidence interval: -0.882 to -0.26; p = 0.01). However, these risk factors did not demonstrate consistent linearity of correlations. Prevalence was lower in people originating from European Union accession countries from April 2001 to March 2011 (-0.63, 95 per cent confidence interval: -0.84 to -0.43; p = 0.002). No correlation between distribution of vestibular schwannomas and socioeconomic risk factors met our threshold criteria (± 0.7).

CONCLUSION

This study demonstrated that there is little variation in distribution of vestibular schwannomas by socioeconomic risk factors.

Prophylactic nimodipine treatment improves hearing outcome after vestibular schwannoma surgery in men: a subgroup analysis of a randomized multicenter phase III trial

A 2016 published randomized multicenter phase III trial of prophylactic nimodipine treatment in vestibular schwannoma surgery showed only a tendency for higher hearing preservation rates in the treatment group. Gender was not included in statistical analysis at that time. A retrospective analysis of the trial considering gender, preoperative hearing, and nimodipine treatment was performed. The treatment group received parenteral nimodipine from the day before surgery until the seventh postoperative day. The control group was not treated prophylactically. Cochlear nerve function was determined by pure-tone audiometry with speech discrimination preoperatively, during in-patient care, and 1 year after surgery and classified according to the Gardner-Robertson grading scale (GR). Logistic regression analysis showed a statistically significant effect for higher hearing preservation rates (pre- and postoperative GR 1–4) in 40 men comparing the treatment (n = 21) and the control (n = 19) groups (p = 0.028), but not in 54 women comparing 27 women in both groups (p = 0.077). The results were also statistically significant for preservation of postoperative hearing with pre- and postoperative GR 1–3 (p = 0.024). There were no differences in tumor sizes between the treatment and the control groups in men, whereas statistically significant larger tumors were observed in the female treatment group compared with the female control group. Prophylactic nimodipine is safe, and an effect for hearing preservation in 40 men with preoperative hearing ability of GR 1–4 was shown in this retrospective investigation. The imbalance in tumor size with larger tumors in females of the treatment group may falsely suggest a gender-related effect. Further investigations are recommended to clarify whether gender has impact on nimodipine’s efficacy.

Screening for vestibular schwannoma in the context of an ageing population

Objective

To review the literature regarding screening for vestibular schwannoma in the context of demographic changes leading to increasing numbers of elderly patients presenting with asymmetric auditory symptoms.

Methods

A systematic review of the literature was performed, with narrative synthesis and statistical analysis of data where appropriate.

Results

Vestibular schwannomas diagnosed in patients aged over 70 years exhibit slower growth patterns and tend to be of smaller size compared to those tumours in younger age groups. This fact, combined with reduced life expectancy, renders the probability of these tumours in the elderly requiring active treatment with surgery or stereotactic radiotherapy to be extremely low. Vestibular schwannomas in the elderly are much more likely to be managed by serial monitoring with magnetic resonance imaging. The weighted yield of magnetic resonance imaging in the diagnosis of vestibular schwannoma in all age groups is 1.18 per cent, with almost 85 scans required to diagnose 1 tumour.

Conclusion

An evidence-based approach to the investigation of asymmetric hearing loss and tinnitus in the elderly patient can be used to formulate guidelines for the rational use of magnetic resonance imaging in this population.

Vestibular Schwanomma: An Experience in a Developing World

Background

Tumors related to the acoustic nerves represent 90% of cerebellopontine angle diseases and have been in the picture for at least 200 years. Famous as acoustic neuromas and vestibular neuromas, these are usually benign, slow-growing tumors of Schwann cells of the myelin sheath. Surgery is the treatment of choice though some authors have suggested "wait and watch" policy. The aims of our study were to study the clinical presentation and management of the tumors, and to evaluate the perioperative outcomes of the surgery.

Methods

A retrospective review of the datasheet of 33 patients diagnosed with vestibular schwanomma who had undergone surgery from January 2014 to January 2017 was performed in National Academy of Medical Sciences, Bir Hospital, Kathmandu, Nepal. Analysis of the demographic data and perioperative outcomes was performed.

Results

Hearing loss was the main presenting symptom in 72% cases followed by tinnitus, dizziness, facial numbness and sudden sensorineural hearing loss. Mean tumur size was 39.7 ± 3 mm. The mean age of the patients was 46 ± 3 years with a female preponderance (1.2:1). In particular, the retrosigmoid route was preferred in all the cases since it was the most employed approach at our center and 63% of the tumors presented to us were grade 5. The surgical techniques allowed safe preservation of the facial function which was 93%. The hearing loss did not improve after the surgery in 94% while it worsened in 6% of cases. We did not find any significant relation between outcome and size, age, gender or laterality of the tumor (P > 0.05). There was no perioperative mortality.

Conclusions

The benign and slow-growing nature of vestibular schwanomma usually poses problems for the early diagnosis and treatment especially in a poor resource setting like ours. Likewise, there are very few studies so far done in the country regarding the incidence and management of the disease. Thus, this study might be helpful in providing insight into the occurrence of the disease in the present scenario and the need for much more studies in the future.

Short-Term Surgical Outcome for Vestibular Schwannoma in Sweden: A Nation-Wide Registry Study

Background: Vestibular Schwannoma (VS) is a benign neoplasm arising from the 8th cranial nerve, with surgery one of the treatment modalities. In a nation-wide registry study, we describe the baseline, treatment characteristics, and short-term outcome in patients surgically treated for VS.

Methods: We performed a nationwide study with data from the Swedish Brain Tumor Registry (SBTR) for all adults diagnosed with VS 2009–2015. Patient symptoms, tumor characteristics, and postoperative complications were analyzed.

Results: In total 348 patients underwent surgery for VS. Mean age was 50.6 ± 14.5 years and 165 patients (47.4%) were female. The most common symptom was focal neurological deficit (92.0%), with only 25 (7.2%) being asymptomatic prior to surgery, and 217 (63.6%) had no restriction in activity. Following surgery, 100 (28.7%) patients developed new deficit(s). In terms of postoperative complications; 11 (3.2%) had a hematoma, 35 (10.1%) an infection, 10 (2.9%) a venous thromboembolism, and 23 (6.6%) had a reoperation due to complication. There were no deaths within 30-days after surgery. When grouped according to tumor size (< 4 vs. ≥4 cm), those with ≥4 cm tumors were more often males (p = 0.02), had more often ICP related symptoms (p = 0.03) and shorter time from imaging to surgery (p < 0.01). Analysis of the younger (< 65 years) vs. elderly (≥65 years) revealed no difference in outcome except increased 1-year mortality (p = 0.002) in elderly.

Conclusion: In this nation-wide registry-study, we benchmark the 30-day complication rate after VS surgery as collected by the SBTR. Further, we present the current neurosurgical outcome data from both VS smaller than 40 mm compared to larger tumors, as well as younger vs. elderly VS patients. Since surgical decision making is a careful consideration of short term risk vs. long term benefit, this information can be useful in clinical decision making.

Predicting Readmission and Reoperation for Benign Cranial Nerve Neoplasms: A Nationwide Analysis

OBJECTIVE

Readmission and reoperation are risks in the resection of benign cranial nerve tumors (BCNTs). This report analyzes the impact of patient-level and surgical factors on these adverse outcomes.

METHODS

This retrospective cohort review comprised patients with a diagnosis of BCNT enrolled in the American College of Surgeons National Surgical Quality Improvement Program registry from 2011 to 2015. Multivariate logistic regression was used to determine the impact of select medical and operative factors on the primary outcomes of readmission and reoperation within 30 days, adjusted for relevant covariates.

RESULTS

We identified 996 patients who underwent resection of a BCNT. The most frequent major complications were readmission (11%), reoperation (8%), surgical site infections (2.6%), and venous thromboembolism (1.5%). The most frequent indications for readmission were management of infection (2.5%), cerebrospinal fluid leak (2.3%), and hydrocephalus (0.5%). Repair of cranial and meningeal defects (3.0%), correction of lagophthalmos (1.2%), and repair of middle ear defects (1.0%) were the most common indications for reoperation. Logistic regression revealed that extremes of age were associated with readmission, whereas preoperative steroid usage, long operative time, and postoperative length of stay >3 days were associated with reoperation (P < 0.05). Obesity trended toward an association with readmission and reoperation.

CONCLUSIONS

Extremes of age were associated with readmission; preoperative steroid use, long operative time, and postoperative length of stay >3 days were associated with reoperation. Surgeons should consider these factors when assessing risk of postoperative complications for BCNTs.

Tumor-Penetrating Delivery of siRNA against TNFα to Human Vestibular Schwannomas

Vestibular schwannoma (VS) is the most common tumor of the cerebellopontine angle, and it typically presents with sensorineural hearing loss. The genomic landscape of schwannoma is complex and many of the molecules implicated in VS pathogenesis represent targets not amenable to antibody-based or small molecule therapeutics. Tumor-targeted delivery of small interfering RNA (siRNA) therapeutics provides a direct and effective means to interrogate targets while minimizing off-target effects. To establish a preclinical model for therapeutic inhibition of putative targets in VS, archived tumor specimens, fresh tumor cells derived from patients with sporadic VS, and an established schwannoma cell line were screened. Nanoparticles directed by the tumor-homing peptide iRGD were selectively taken up by primary VS cultures in vitro via interactions with αvβ3/β5 integrins and neuropilin-1 (NRP-1). Cellular uptake was inhibited by a neutralizing antibody against αv integrin in a dose-dependent manner. When applied to primary VS cultures, iRGD-targeted nanoparticles delivered siRNA directed against TNFα in a receptor-specific fashion to potently silence gene expression and protein secretion. Taken together, our results provide a proof of principle for tumor-targeted, nanoparticle-mediated delivery of siRNA to VS and establish a novel platform for the development and pre-clinical screening of molecular therapeutics against VS.

Laryngeal Schwannoma: A Case Presentation and Review of the Mayo Clinic Experience

OBJECTIVES

The aim of this study was to clarify the nature of laryngeal schwannomas through review of the experience of a single institution during a 104-year period.

STUDY DESIGN

This is a retrospective case series.

METHODS

The Mayo Clinic, Rochester, Minnesota clinical and surgical pathology database was reviewed for the years 1985-2011. Four cases of laryngeal schwannoma were identified. These cases were pooled with a previously published series of laryngeal schwannomas treated at our institution between 1907 and 1986. The characteristics of all 11 cases were studied, and relevant literature was reviewed.

RESULTS

A total of 11 cases of schwannoma of the larynx were identified. The mean age at presentation was 48 years (range 12-73 years). The most common presenting symptoms were dysphonia and dysphagia. The most frequently involved primary site was the false vocal fold (six patients), followed by the aryepiglottic fold (three), epiglottis (two), subglottis (two), ventricle (one), true vocal fold (one) and postcricoid region (one). The mean maximal tumor diameter was 2.5 cm. In all but one case, surgical excision was curative with no recurrence during recorded follow up ranging from 1 to 17 years.

CONCLUSIONS

Laryngeal schwannomas, although rare, should be considered in the differential diagnosis of laryngeal tumors. They occur most frequently in the false vocal fold and present most commonly with dysphonia and/or dysphagia. Surgical excision is the treatment of choice.

Secreted Factors from Human Vestibular Schwannomas Can Cause Cochlear Damage

Vestibular schwannomas (VSs) are the most common tumours of the cerebellopontine angle. Ninety-five percent of people with VS present with sensorineural hearing loss (SNHL); the mechanism of this SNHL is currently unknown. To establish the first model to study the role of VS-secreted factors in causing SNHL, murine cochlear explant cultures were treated with human tumour secretions from thirteen different unilateral, sporadic VSs of subjects demonstrating varied degrees of ipsilateral SNHL. The extent of cochlear explant damage due to secretion application roughly correlated with the subjects' degree of SNHL. Secretions from tumours associated with most substantial SNHL resulted in most significant hair cell loss and neuronal fibre disorganization. Secretions from VSs associated with good hearing or from healthy human nerves led to either no effect or solely fibre disorganization. Our results are the first to demonstrate that secreted factors from VSs can lead to cochlear damage. Further, we identified tumour necrosis factor alpha (TNFα) as an ototoxic molecule and fibroblast growth factor 2 (FGF2) as an otoprotective molecule in VS secretions. Antibody-mediated TNFα neutralization in VS secretions partially prevented hair cell loss due to the secretions. Taken together, we have identified a new mechanism responsible for SNHL due to VSs.

Near total extirpation of vestibular schwannoma with salvage radiosurgery

OBJECTIVES/HYPOTHESIS

The management of a sporadic vestibular schwannoma (VS) has changed with the introduction of stereotactic radiosurgery (SRS). Because functional outcome is important, particularly regarding the facial nerve, a policy of near-total surgical resection of a large-size VS has emerged, minimizing damage to the facial nerve. The debate remains whether the surgical remnant should be treated immediately or after established growth.

STUDY DESIGN

Retrospective case series.

METHODS

A consecutive cohort of 55 patients underwent a retrosigmoid craniotomy and near-total removal of a large-size VS at our university medical center between 2005 and 2011 and had a follow-up of a least 3 years. Documented growth of the VS remnant after surgery necessitating adjuvant SRS was the primary outcome measure using analysis of variance.

RESULTS

In 45 patients (81.8%), a small tumor remnant was left during surgery. The mean preoperative tumor volume was 12.2 cm(3) (range, 1.13-50.16 cm(3)); the mean volume of the remnant was 0.22 cm(3) (range, 0-1.52 cm(3)). The mean postoperative follow-up time was 35.4 months (range, 3-76 months). Salvage SRS was deemed necessary in seven patients (13.0%). The size of the postoperative tumor remnant was a significant predictor for the necessity of postoperative adjuvant SRS. Normal facial nerve function (House-Brackmann [HB] I) was preserved in 30 patients (57.7%), 17 patients (32.7%) experienced a permanent mild facial nerve deficit (HB II, III), and five patients (9.6%) experienced a severe facial nerve deficit (HB grade IV-VI).

CONCLUSIONS

Initial observation after near total surgical removal of VS is a feasible strategy, with only a minority requiring salvage radiosurgery during follow-up.

[Treatment of giant acoustic neuromas]

INTRODUCTION AND OBJECTIVES

To analyze the treatment modality and outcome of a series of patients with giant acoustic neuromas, a particular type of tumour characterised by their size (extracanalicular diameter of 4cm or more) and high morbidity and mortality.

MATERIALS AND METHODS

This was a retrospective unicentre study of patients with acoustic neuromas treated in a period of 12 years. In our institutional series of 108 acoustic neuromas operated on during that period, we found 13 (12%) cases of giant acoustic neuromas. We reviewed the available data of these cases, including presentation and several clinical, anatomical, and microsurgical aspects.

RESULTS

All patients were operated on by the same neurosurgeon and senior author (EU) using the suboccipital retrosigmoid approach and complete microsurgical removal was achieved in 10 cases. In one case, near total removal was deliberately performed, in another case a CSF shunt was placed as the sole treatment measure, and in the remaining case no direct treatment was given. One patient died in the immediate postoperative period. One year after surgery, 4 patients showed facial nerve function of iii or more in the House-Brackman scale.

CONCLUSIONS

The 4 most important prognostic characteristics of giant acoustic neuromas are size, adhesion to surrounding structures, consistency and vascularity. Only the first of these is evident in neuroimaging. Giant acoustic neuromas are characterised by high morbidity at presentation as well as after treatment. Nevertheless, the objective of complete microsurgical removal with preservation of cranial nerve function is attainable in some cases through the suboccipital retrosigmoid approach.