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European Annals of Otorhinolaryngology,... Nov 2013The widespread development of cell-phones entails novel user exposure to electromagnetic fields. Health impact is a public health issue and a source of anxiety in the... (Review)
Review
The widespread development of cell-phones entails novel user exposure to electromagnetic fields. Health impact is a public health issue and a source of anxiety in the population. Some clinical studies reported an association between cell and cordless phone use and vestibular schwannoma; others found none. A systematic review was performed of all published clinical studies (cohort, registry, case-control and validation studies), with analysis of results, to determine the nature of the association and the level of evidence. Cohort studies were inconclusive due to short exposure durations and poor representativeness. Registry studies showed no correlation between evolution of cell-phone use and incidence of vestibular schwannoma. Case-control studies reported contradictory results, with methodological flaws. Only a small number of subjects were included in long-term studies (>10 years), and these failed to demonstrate any indisputable causal relationship. Exposure assessment methods were debatable, and long-term assessment was lacking. An on-going prospective study should determine any major effect of electromagnetic fields; schwannoma being a rare pathology, absence of association will be difficult to prove. No clinical association has been demonstrated between cell and cordless phone use and vestibular schwannoma. Existing studies are limited by their retrospective assessment of exposure.
Topics: Causality; Cell Phone; Cross-Sectional Studies; Electromagnetic Fields; Humans; Neuroma, Acoustic; Risk
PubMed: 23725662
DOI: 10.1016/j.anorl.2012.05.005 -
Brazilian Journal of Otorhinolaryngology 2009The vestibulocochlear nerve schwannoma (VS) is a benign tumor that stems from the edge of the Schwann s sheath. It is considered the most frequent intracranial benign... (Review)
Review
UNLABELLED
The vestibulocochlear nerve schwannoma (VS) is a benign tumor that stems from the edge of the Schwann s sheath. It is considered the most frequent intracranial benign tumor, of low lethality rate and unknown etiology.
AIM
to identify risk factors associated with VS.
STUDY DESIGN
systematic review.
METHODS
electronic search of studies using the following key words: 'risk', 'schwannoma', 'vestibular', 'neuroma' and 'acoustic'. All original articles on epidemiological studies published in Portuguese, English or Spanish describing measures of association were included.
RESULTS
twenty case-control studies were found, most of them published in the United States. The analysis of those studies shows educational level, household income, occupation, exposure to ionizing radiation and noise, allergic diseases as well as the use of both cellular and cordless phones as risk factors for the VS.
CONCLUSION
methodological limitations and lack of precision in the findings impose limits to definitive conclusions concerning those risk factors. The current study contributes with information which can subsidize decisions related to the methodology to be used, having in mind new investigations on risk factors for VS. Therefore, it is of great help for knowledge improvement in this field.
Topics: Adult; Environmental Exposure; Female; Humans; Male; Middle Aged; Neuroma, Acoustic; Risk Factors; Time Factors
PubMed: 19784431
DOI: 10.1016/s1808-8694(15)30501-2 -
Journal of Neuro-oncology May 2009Facial nerve preservation is a critical measure of clinical outcome after vestibular schwannoma treatment. Gamma Knife radiosurgery has evolved into a practical... (Review)
Review
OBJECTIVE
Facial nerve preservation is a critical measure of clinical outcome after vestibular schwannoma treatment. Gamma Knife radiosurgery has evolved into a practical treatment modality for vestibular schwannoma patients, with several reported series from a variety of centers. In this study, we report the results of an objective analysis of reported facial nerve outcomes after the treatment of vestibular schwannomas with Gamma Knife radiosurgery.
MATERIALS AND METHODS
A Boolean Pub Med search of the English language literature revealed a total of 23 published studies reporting assessable and quantifiable outcome data regarding facial nerve function in 2,204 patients who were treated with Gamma Knife radiosurgery for vestibular schwannoma. Inclusion criteria for articles were: (1) Facial nerve preservation rates were reported specifically for vestibular schwannoma, (2) Facial nerve functional outcome was reported using the House-Brackmann classification (HBC) for facial nerve function, (3) Tumor size was documented, and (4) Gamma Knife radiosurgery was the only radiosurgical modality used in the report. The data were then aggregated and analyzed based on radiation doses delivered, tumor volume, and patient age.
RESULTS
An overall facial nerve preservation rate of 96.2% was found after Gamma Knife radiosurgery for vestibular schwannoma in our analysis. Patients receiving less than or equal to 13 Gy of radiation at the marginal dose had a better facial nerve preservation rate than those who received higher doses (
13 Gy = 94.7%, P < 0.0001). Patients with a tumor volume less than or equal to 1.5 cm(3) also had a greater facial nerve preservation rate than patients with tumors greater than 1.5 cm(3) ( 1.5 cm(3) 95.5%, P < 0.0001). Superior facial nerve preservation was also noted in patients younger than or equal to 60 years of age (96.8 vs. 89.4%, P < 0.0001). The average reported follow up duration in this systematic review was 54.1 +/- 31.3 months. CONCLUSION
Our analysis of case series data aggregated from multiple centers suggests that a facial nerve preservation rate of 96.2% can be expected after Gamma knife radiosurgery for vestibular schwannoma. Younger patients with smaller tumors less than 1.5 cm(3) and treated with lower doses of radiation less than 13 Gy will likely have better facial nerve preservation rates after Gamma Knife radiosurgery for vestibular schwannoma.
Topics: Age Factors; Facial Nerve; Facial Nerve Injuries; Humans; Middle Aged; Neuroma, Acoustic; Postoperative Complications; Radiosurgery; Radiotherapy Dosage
PubMed: 19430881
DOI: 10.1007/s11060-009-9842-3 -
Health Technology Assessment... Mar 2009To evaluate the clinical effectiveness and cost-effectiveness of a range of diagnostic strategies for investigating patients with unilateral hearing loss and/or... (Review)
Review
OBJECTIVE(S)
To evaluate the clinical effectiveness and cost-effectiveness of a range of diagnostic strategies for investigating patients with unilateral hearing loss and/or tinnitus, with a view to confirming or eliminating a diagnosis of acoustic neuroma, and to describe the natural history of acoustic neuroma.
DATA SOURCES
Major electronic databases were searched from January 1980 to August 2008.
REVIEW METHODS
Selected studies were assessed and subjected to data extraction and quality assessment using standard methods.
RESULTS
Studies comparing auditory brainstem response (ABR) with magnetic resonance (MR) imaging were highly heterogeneous. ABR has high sensitivity compared with MR imaging for acoustic neuromas greater than 1 cm in size but not for smaller neuromas. The sensitivities of T2-weighted (T2W) and T2-star-weighted (T2*W) imaging strategies compared with gadolinium-enhanced T1-weighted (GdT1W) MR imaging (gold standard) were high and relatively homogeneous. The specificity of T2W and T2*W studies ranged from 90% to 100% and from 86% to 99% respectively. The review of cost-effectiveness showed that GdT1W MR imaging immediately or in conjunction with ABR appears to be more cost-effective than 'traditional' protocols; ABR/GdT1W MR imaging protocols were more cost-effective than going directly to GdT1W MR imaging. Non-contrast-enhanced MR imaging was found to be a more cost-effective test for acoustic neuroma than GdT1W MR imaging. The incidence of acoustic neuroma has increased over the last 30 years, with the median age at diagnosis remaining at 55 years. Most patients present with insidious symptoms of unilateral hearing impairment, tinnitus and/or vertigo. The pattern and rate of growth of acoustic neuroma are highly variable and currently unpredictable. At least 50% of tumours do not grow, at least for some years after diagnosis. Some studies have found large initial size to be a determinant of later growth, with the opposite also being reported. The mean growth rate for all tumours varies between 1 and 2 mm/year, with a rate of 2-4 mm/year for only those that grow; however, there are cases with significant regression (5%) or exceptional growth (which may exceed 18 mm/year).
CONCLUSIONS
The majority of the evidence reviewed was poorly reported and there is therefore an inherent risk of bias. Given the recent improvement in resolution and reduction in cost of MR imaging, ABR can no longer be considered appropriate as the primary test used to screen for acoustic neuroma. T2W or T2*W sequences enable accurate evaluation of the VIIIth and VIIth cranial nerves within the cerebellopontine angle and internal auditory canal as well as evaluation of the cochlea and labyrinth, and inclusion of GdT1W sequences is unlikely to contribute information that would alter patient management in the screening population. The quality of the imaging chain and experience of the reporting radiologist are key factors determining the efficacy of a non-contrast screening strategy. Based on a cost-effectiveness model developed to reflect UK practice it was concluded that a diagnostic algorithm that deploys non-contrast MR imaging as an initial imaging screen in the investigation of acoustic neuroma is less costly than and likely to be as effective as available contrast MR imaging.
Topics: Age Distribution; Cost-Benefit Analysis; Evoked Potentials, Auditory, Brain Stem; Hearing Tests; Humans; Incidence; Magnetic Resonance Imaging; Neuroma, Acoustic; Prevalence; Reproducibility of Results; Technology Assessment, Biomedical
PubMed: 19358774
DOI: 10.3310/hta13180 -
Brazilian Journal of Otorhinolaryngology 2008Telecommunications systems emit radiofrequency, which is an invisible electromagnetic radiation. Mobile phones operate with microwaves (450900 MHz in the analog service,... (Review)
Review
UNLABELLED
Telecommunications systems emit radiofrequency, which is an invisible electromagnetic radiation. Mobile phones operate with microwaves (450900 MHz in the analog service, and 1,82,2 GHz in the digital service) very close to the users ear. The skin, inner ear, cochlear nerve and the temporal lobe surface absorb the radiofrequency energy.
AIM
literature review on the influence of cellular phones on hearing and balance.
STUDY DESIGN
systematic review.
METHODS
We reviewed papers on the influence of mobile phones on auditory and vestibular systems from Lilacs and Medline databases, published from 2000 to 2005, and also materials available in the Internet.
RESULTS
Studies concerning mobile phone radiation and risk of developing an acoustic neuroma have controversial results. Some authors did not see evidences of a higher risk of tumor development in mobile phone users, while others report that usage of analog cellular phones for ten or more years increase the risk of developing the tumor. Acute exposure to mobile phone microwaves do not influence the cochlear outer hair cells function in vivo and in vitro, the cochlear nerve electrical properties nor the vestibular system physiology in humans. Analog hearing aids are more susceptible to the electromagnetic interference caused by digital mobile phones.
CONCLUSION
there is no evidence of cochleo-vestibular lesion caused by cellular phones.
Topics: Animals; Auditory Perceptual Disorders; Cell Phone; Electromagnetic Fields; Humans; Neuroma, Acoustic; Otoacoustic Emissions, Spontaneous; Rats; Risk Factors; Time Factors; Vestibule, Labyrinth
PubMed: 18392513
DOI: 10.1016/s1808-8694(15)30762-x