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Journal of Neurosurgery Nov 2020Multiple short series have evaluated the efficacy of salvage microsurgery (MS) after stereotactic radiosurgery (SRS) for treatment of vestibular schwannomas (VSs);... (Review)
Review
OBJECTIVE
Multiple short series have evaluated the efficacy of salvage microsurgery (MS) after stereotactic radiosurgery (SRS) for treatment of vestibular schwannomas (VSs); however, there is a lack of a large volume of patient data available for interpretation and clinical adaptation. The goal of this study was to provide a comprehensive review of tumor characteristics, management, and surgical outcomes of salvage of MS after SRS for VS.
METHODS
The Medline/PubMed, Scopus, CINAHL, Cochrane Library, and Google Scholar databases were queried according to PRISMA guidelines. All English-language and translated publications were included. Studies lacking adequate study characteristics and outcomes were excluded. Cases involving neurofibromatosis type 2, previous MS, or malignant transformation were excluded when possible.
RESULTS
Twenty studies containing 297 cases met inclusion criteria. Three additional cases from Rush University Medical Center were added for 300 total cases. Tumor growth with or without symptoms was the primary indication for salvage surgery (92.3% of cases), followed by worsening of symptoms without growth (4.6%) and cystic enlargement (3.1%). The average time to MS after SRS was 39.4 months. The average size and volume of tumor at surgery were 2.44 cm and 5.92 cm3, respectively. The surgical approach was retrosigmoid (42.8%) and translabyrinthine (57.2%); 59.5% of patients had a House-Brackmann (HB) grade of I or II. The facial nerve was preserved in 91.5% of cases. Facial nerve preservation and HB grades were lower for the translabyrinthine versus retrosigmoid approach (p = 0.31 and p = 0.18, respectively); however, fewer complications were noted in the translabyrinthine approach (p = 0.29). Gross-total resection (GTR) was completed in 55.7% of surgeries. Studies that predominantly used subtotal resection (STR) were associated with a lower rate of facial nerve injury (5.3% vs 11.3%, p = 0.07) and higher rate of HB grade I or II (72.9% vs 48.0%, p = 0.00003) versus those using predominantly GTR. However, majority STR was associated with a recurrence rate of 3.6% as compared to 1.4% for majority GTR (p = 0.29).
CONCLUSIONS
This study showed that the leading cause of MS after SRS was tumor growth at an average of 39.4 months after radiation. There were no significant differences in outcomes of facial nerve preservation, postoperative HB grade, or complication rate based on surgical approach. Patients who underwent STR showed statistically significant better HB outcomes compared with GTR. MS after SRS was considered by most authors to be more difficult than primary MS. These data support the notion that the surgical goals of salvage surgery are debulking of tumor mass, decreasing compression of the brainstem, and not necessarily pursuing GTR.
PubMed: 34331121
DOI: 10.3171/2020.7.JNS2044 -
The Journal of Laryngology and Otology Nov 2023Stereotactic radiosurgery has been shown to be an effective method of managing vestibular schwannomas. The primary aim here is to establish the impact of pre-treatment... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Stereotactic radiosurgery has been shown to be an effective method of managing vestibular schwannomas. The primary aim here is to establish the impact of pre-treatment fast-growing vestibular schwannomas on the efficacy of stereotactic radiosurgery.
METHODS
PubMed, Medline and Embase databases were used. The ROBINS-I ('Risk Of Bias In Non-randomised Studies - of Interventions') tool was utilised to assess for risk of bias. Proportionate meta-analysis and sub-analysis for fast-growing tumours were performed to explore the success rate of stereotactic radiosurgery in stabilising or decreasing the tumour burden in vestibular schwannomas.
RESULTS
Four moderate risk studies were included in the analysis. Overall, 91 per cent (95 per cent confidence interval = 0.83-0.97, < 0.01, = 80 per cent) of the tumours demonstrated successful size reduction or stabilisation following stereotactic radiosurgery. Nevertheless, the efficacy of stereotactic radiosurgery in reducing or stabilising fast-growing vestibular schwannomas decreased by 79 per cent (95 per cent confidence interval = 0.64-0.91, = 0.11, = 62 per cent).
CONCLUSION
Stereotactic radiosurgery has a statistically significant success rate in stabilising or decreasing the vestibular schwannoma size. This success rate is diminished in fast-growing vestibular schwannomas.
Topics: Humans; Neuroma, Acoustic; Radiosurgery; Microsurgery
PubMed: 37194631
DOI: 10.1017/S0022215123000786 -
Wideochirurgia I Inne Techniki... Sep 2022Intracanalicular vestibular schwannomas (IVS) account for 8% of all vestibular schwannomas and their detection is still increasing due to high availability of magnetic... (Review)
Review
Intracanalicular vestibular schwannomas (IVS) account for 8% of all vestibular schwannomas and their detection is still increasing due to high availability of magnetic resonance (MRI). Radiosurgery is one of several commonly acceptable methods of IVS treatment, but some risk may still exist with that treatment. The aim of this study is to analyze the clinical outcomes in tumor control and hearing preservation after radiosurgery of IVS. The retrospective analysis included 14 scientific papers available in the PubMed database. Assessment of tumor volume was performed based on gadolinium-enhanced T1-weighted scans. Hearing preservation was assessed using the Gardner-Robertson classification (GR class). Statistical analysis was performed using IBM SPSS Statistics 27. It was revealed that tumor growth control in IVS treated with radiosurgery was higher than in the wait-and-see strategy. The hearing preservation was similar in patients after wait and see and the surgical group. Radiosurgery was associated with low risk of facial nerve dysfunction.
PubMed: 36187055
DOI: 10.5114/wiitm.2022.115169 -
Otology & Neurotology : Official... Mar 2021To perform a systematic review and meta-analysis summarizing the current evidence on the management of intracanalicular vestibular schwannoma. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To perform a systematic review and meta-analysis summarizing the current evidence on the management of intracanalicular vestibular schwannoma.
DATA SOURCES
Embase (1947-), Medline (1946-), Cochrane library (1947-), Scopus (2010-), and CINAHL (1961-) were searched from 1969 to October 5, 2019 (50 years).
STUDY SELECTION
A search strategy was performed to identify patients with vestibular schwannoma confined to the internal auditory canal without extension to the cerebellopontine angle. Studies with patients aged less than 18, Neurofibromatosis type 2, revision cases, and non-English language were excluded.
DATA EXTRACTION
A standardized collection sheet was used for the extracted data and a quality assessment was performed using the Newcastle-Ottawa Scale with the comparability criterion omitted.
DATA SYNTHESIS
Seventy-one studies were included with 24 on observation, 14 on radiotherapy, and 34 on surgery. The primary outcome was serviceable hearing preservation. Secondary outcomes were preservation of facial nerve function, growth, involution, and dizziness. Sub-analysis on the type of surgery and type of radiotherapy were performed. Excel 2016 with MIX 2.0 Pro add-on package was used to analyze the data and create forest plots. Data were presented in proportion with a 95% confidence interval.
CONCLUSIONS
Serviceable hearing was observed in 31% of patients after observation, 56% after radiotherapy, and 51% after surgical treatment with mean follow-up time of 4.04 years, 4.92 years, and 2.23 years, respectively. Facial nerve function was found to be best preserved in both observation and radiotherapy groups. Vestibular schwannoma growth occurred in 33% of patients under observation. Involution occurred in 2% of patients under observation and in 38% after radiotherapy.
Topics: Aged; Hearing; Hearing Loss; Hearing Tests; Humans; Neuroma, Acoustic; Radiosurgery; Treatment Outcome
PubMed: 33555742
DOI: 10.1097/MAO.0000000000002979 -
The Laryngoscope Sep 2023To systematically review and evaluate metformin's potential impact on vestibular schwannoma (VS) growth. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
To systematically review and evaluate metformin's potential impact on vestibular schwannoma (VS) growth.
DATA SOURCES
PubMed, Cochrane Library, and Embase.
REVIEW METHODS
A retrospective cohort study was performed on sporadic VS patients undergoing initial observation who had at least two magnetic resonance imaging studies. Patients were stratified by metformin use during the observation period. Primary endpoint was VS growth, defined as at least a 2 mm increase in diameter. Survival free of tumor growth was evaluated between groups. Systematic review and meta-analysis were performed to produce a pooled odds ratio [OR]. Study heterogeneity was assessed and post-hoc power analysis was performed.
RESULTS
A total of 123 patients were included, of which 17% were taking metformin. Median patient age was 56.6 years (range, 25.1-84.5). There were no statistically significant differences between the groups. Survival analysis did not demonstrate a statistically significant difference in time to VS growth between groups (hazard ratio = 0.61, 95% confidence interval [CI] = 0.29-1.29). Furthermore, logistic regression analysis did not demonstrate a statistically significant difference between groups in the odds of VS growth (OR = 0.46, 95% CI = 0.17-1.27). Systematic review identified 3 studies. Meta-analysis suggested that metformin reduces the odds of developing VS growth (pooled OR = 0.45, 95% CI = 0.29-0.71). Studies demonstrated low between-study heterogeneity. Power analysis demonstrated a sample size of 220 patients with equal randomization would be required to prospectively identify a true difference with 80% power.
CONCLUSIONS
Metformin use may reduce the odds of VS growth. A randomized trial would be ideal to identify an unbiased estimate of metformin's effect on VS growth. Laryngoscope, 133:2066-2072, 2023.
Topics: Humans; Adult; Middle Aged; Aged; Aged, 80 and over; Neuroma, Acoustic; Metformin; Retrospective Studies; Magnetic Resonance Imaging; Survival Analysis
PubMed: 36744870
DOI: 10.1002/lary.30601 -
Frontiers in Surgery 2022Survival amongst posterior fossa tumour (PFT) patients is improving. Clinical endpoints such as overall survival fail to depict QoL. There is yet to be a review of... (Review)
Review
INTRODUCTION
Survival amongst posterior fossa tumour (PFT) patients is improving. Clinical endpoints such as overall survival fail to depict QoL. There is yet to be a review of current QoL instruments used for adult PFTs. Aim of this review is to outline the QoL reporting in the management of PFTs and measure participation level.
METHODS
This systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis. A search strategy to identify adult patients with PFTs who took part in QoL metrics was conducted. Observational and experimental studies published from 1990 to date were included. Studies with a sample size less than 10 and performance measures such as Karnofsky Performance Status were not considered.
RESULTS
A total of 116 studies were included in the final analysis. Vestibular schwannomas were the most common tumour pathology ( = 23,886, 92.6%) followed by pilocytic astrocytomas ( = 657, 2.5%) and meningiomas ( = 437, 1.7%) Twenty-five different QoL measures were used in the study pool. SF-36 was the most common ( = 55, 17 47.4%) QoL metric in the whole study pool, followed by the Penn Acoustic Neuroma QoL scale ( = 24, 20.7%) and Dizziness Handicap Inventory ( = 16, 13.8%). Seventy-two studies reported less-than 100% participation in QoL evaluation. The commonest reason for non-participation was a lack of response ( = 1,718, 60.8%), incomplete questionnaires ( = 268, 9.4%) and cognitive dysfunction ( = 258, 9.1%).
CONCLUSION
Informed clinical decision-making in PFT patients requires the development of specific QoL outcomes. Core outcome sets, and minimal clinically important differences (MCID) are essential for these metrics to show clinically significant improvements in patient QoL.
PubMed: 36303860
DOI: 10.3389/fsurg.2022.970889 -
World Neurosurgery Apr 2022A meta-analysis of patients with sporadic vestibular schwannoma (VS) primarily treated with stereotactic radiosurgery (SRS) or microsurgery (MS) was performed, and... (Meta-Analysis)
Meta-Analysis Review
Primary Treatment of Small to Medium (<3 cm) Sporadic Vestibular Schwannomas: A Systematic Review and Meta-Analysis on Hearing Preservation and Tumor Control Rates for Microsurgery versus Radiosurgery.
BACKGROUND
A meta-analysis of patients with sporadic vestibular schwannoma (VS) primarily treated with stereotactic radiosurgery (SRS) or microsurgery (MS) was performed, and hearing preservation outcome (HPO), tumor control (TC), and facial nerve dysfunction (FND) were analyzed.
METHODS
A systematic review was conducted (Medline and Scopus database) for the period January 2010-June 2020 with appropriate MeSH. English language articles for small to medium sporadic VS (<3 cm) using SRS or MS as primary treatment modality, with minimum follow-up of 3 years, were included. Studies had to report an acceptable standardized hearing metric.
RESULTS
Thirty-two studies met the inclusion criteria: 10 MS; 23 radiosurgery, and 1 comparative study included in both. HPO, at approximately 65 months follow-up, were comparable between MS group (10 studies; 809 patients) and SRS group (23 studies; 1234 patients) (56% vs. 59%; P = 0.1527). TC, at approximately 70 months follow-up, was significantly better in the MS group (9 studies; 1635 patients) versus the SRS group (19 studies; 2260 patients) (98% vs. 92%; P < 0.0001). FND, at approximately 12 months follow-up, was significantly higher in the MS group (8 studies; 1101 patients) versus the SRS group (17 studies; 2285 patients) (10% vs. 2%; P < 0.0001).
CONCLUSIONS
MS and SRS are comparable primary treatments for small (<3 cm) sporadic VS with respect to HPO at 5-year follow-up in patients with serviceable hearing at presentation; approximately 50% of patients for both modalities likely lose serviceable hearing by that time point. High TC rates (>90%) were seen with both modalities; MS 98% versus SRS 92%. The posttreatment FND was significantly less with the SRS group (2%) versus the MS group (10%).
Topics: Follow-Up Studies; Hearing; Humans; Microsurgery; Neuroma, Acoustic; Radiosurgery; Retrospective Studies; Treatment Outcome
PubMed: 34838768
DOI: 10.1016/j.wneu.2021.11.083 -
Journal of Neuro-oncology Oct 2023To perform a systematic review of literature specific to single-fraction stereotactic radiosurgery (SRS) for large vestibular schwannomas (VS), maximum... (Review)
Review
Single-fraction radiosurgery outcomes for large vestibular schwannomas in the upfront or post-surgical setting: a systematic review and International Stereotactic Radiosurgery Society (ISRS) Practice Guidelines.
PURPOSE
To perform a systematic review of literature specific to single-fraction stereotactic radiosurgery (SRS) for large vestibular schwannomas (VS), maximum diameter ≥ 2.5 cm and/or classified as Koos Grade IV, and to present consensus recommendations on behalf of the International Stereotactic Radiosurgery Society (ISRS).
METHODS
The Medline and Embase databases were used to apply the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach. We considered eligible prospective and retrospective studies, written in the English language, reporting treatment outcomes for large VS; SRS for large post-operative tumors were analyzed in aggregate and separately.
RESULTS
19 of the 229 studies initially identified met the final inclusion criteria. Overall crude rate of tumor control was 89% (93.7% with no prior surgery vs 87.7% with prior surgery). Rates of salvage microsurgical resection, need for shunt, and additional SRS in all series versus those with no prior surgery were 9.6% vs 3.3%, 4.7% vs 6.4% and 1% vs 0.9%, respectively. Rates of facial palsy and hearing preservation in all series versus those with no prior surgery were 1.3% vs 3.4% and 34.2% vs 40.4%, respectively.
CONCLUSIONS
Upfront SRS resulted in high rates of tumor control with acceptable rates of facial palsy and hearing preservation as compared to the results in those series including patients with prior surgery (level C evidence). Therefore, although large VS are considered classic indication for microsurgical resection, upfront SRS can be considered in selected patients and we recommend a prescribed marginal dose from 11 to 13 Gy (level C evidence).
Topics: Humans; Radiosurgery; Retrospective Studies; Neuroma, Acoustic; Prospective Studies; Facial Paralysis; Treatment Outcome; Follow-Up Studies
PubMed: 37843727
DOI: 10.1007/s11060-023-04455-8 -
La Clinica Terapeutica May 2021Over the process of establishing the causal relation-ship, medical and legal methodologies may be at variance over the definitional standards and terminologies applied,...
Can a causal relationship be established between acoustic neuroma and occupational exposure to non-ionizing radiations from mobile devices? Comparison between scientific literature data and medico-legal methodology.
BACKGROUND
Over the process of establishing the causal relation-ship, medical and legal methodologies may be at variance over the definitional standards and terminologies applied, which can hinder the activities of expert witnesses.
OBJECTIVES
The article's authors have set out to assess whether, and under what conditions, a causal relationship can be established between acoustic neuroma and exposure to non-ionizing radiation from mobile communication devices.
METHODS
The study design is a Systematic Review. The authors have drawn upon a 2020 Turin Court of Appeals ruling which found such a causal relationship in a somewhat peculiar case: rare tumor and exposure to non-ionizing radiation of unusually long and regular dura-tion. The case presents several peculiarities, herein analyzed in light of a) scientific evidence relative to the etiopathogenesis of the neuroma; b) available medico-legal literature defining causality evaluation criteria, and lastly c) court filings in regard to the probability standards applied to prove causal relationship.
RESULTS
A direct tie cannot be proven, not even in cases of sub-stantially intense and lengthy exposure, if the medico-legal standards applied are not consistent enough to prove that nexus is more likely than not.
DISCUSSION
Several elements suggest a causal relationship is unlikely: a) a dearth of evidence on humans; b) rats exposed to such radiation have developed cardiac tumors, not in their ears; c) exposure has caused no tumors in mice; d) the length of exposure is incompat-ible with tumor size and type. That fourth point only concerns the case herein explored, whereas the first three have a general scope of validity. The main limitation of the present study design is the heterogeneity among the included studies. Retrospective and prospective studies have been included, which may be a source of bias.
Topics: Animals; Causality; Computers, Handheld; Humans; Mice; Neuroma, Acoustic; Occupational Exposure; Radiation, Nonionizing; Rats; Risk Factors
PubMed: 33956036
DOI: 10.7417/CT.2021.2313 -
International Journal of Molecular... Mar 2023Although diagnosis and treatment of vestibular schwannomas (VSs) improved in recent years, no factors have yet been identified as being capable of predicting tumor...
Although diagnosis and treatment of vestibular schwannomas (VSs) improved in recent years, no factors have yet been identified as being capable of predicting tumor growth. Molecular rearrangements occur in neoplasms before any macroscopic morphological changes become visible, and the former are the underlying cause of disease behavior. Tumor microenvironment (TME) encompasses cellular and non-cellular elements interacting together, resulting in a complex and dynamic key of tumorigenesis, drug response, and treatment outcome. The aim of this systematic, narrative review was to assess the level of knowledge on TME implicated in the biology, behavior, and prognosis of sporadic VSs. A search (updated to November 2022) was run in Scopus, PubMed, and Web of Science electronic databases according to the PRISMA guidelines, retrieving 624 titles. After full-text evaluation and application of inclusion/exclusion criteria, 37 articles were included. VS microenvironment is determined by the interplay of a dynamic ecosystem of stromal and immune cells which produce and remodel extracellular matrix, vascular networks, and promote tumor growth. However, evidence is still conflicting. Further studies will enhance our understanding of VS biology by investigating TME-related biomarkers able to predict tumor growth and recognize immunological and molecular factors that could be potential therapeutic targets for medical treatment.
Topics: Humans; Ecosystem; Neuroma, Acoustic; Treatment Outcome; Tumor Burden; Tumor Microenvironment
PubMed: 37047498
DOI: 10.3390/ijms24076522