Judicious and evidence-based use of radiosurgery - recommendations for low-middle income countries.

Surgical removal remains the primary treatment for most brain tumours. However, radiosurgery presents an effective, less invasive alternative or additional treatment for certain types. Our goal was to explore radiosurgery's roles in treating various brain tumours, focussing on its application in low- and middle-income countries (LMICs). We reviewed all relevant systematic reviews, metaanalyses, and guidelines to determine the most effective radiosurgical approaches. Additionally, we consulted a panel of experts with over ten years of experience in LMICs, such as Pakistan. For brain tumours, stereotactic radiosurgery should generally follow a confirmed histopathological diagnosis. Exceptions include tumours identified through Magnetic Resonance Imaging (MRI), like Vestibular Schwannoma (VS), pre-diagnosed Neurofibromatosis type 2 (NF2), multiple typical meningiomas, and metastases with a known histology from another site. While radiosurgery is gaining traction as a primary and adjunct treatment in some LMICs, the lack of regional guidelines, trained personnel, and collaboration among specialists hinders its wider adoption. Addressing these gaps is crucial for expanding radiosurgical care in these regions.

Clinical and economic burden of neurofibromatosis type 2 in the United States.

OBJECTIVES: We aimed to investigate the prevalence and cost-associated risk factors for hospital stays for Neurofibromatosis Type 2 (NF2) patients in the past decade. PATIENTS AND METHODS: A multi-year cross-sectional study was performed using the National Inpatient Sample. Patients with a diagnosis code of NF2 according to the International Classification of Diseases, 9th Revision, Clinical Modification coding system were queried from 2006-2014. Sampling discharge weights were used to calculate trend estimates for national demographics, hospital characteristics, comorbidities, and surgical interventions. Regression analysis was performed to determine significant independent associations between comorbidities and admission cost. RESULTS: From 2006-2014, there were 5,078 discharges for patients diagnosed with NF2. Patient demographics, comorbidities, and procedures performed were overall consistent over time. The most common admission diagnoses were hearing loss (28.2 %), acoustic schwannoma (14.3 %), cranial meningioma (11.8 %) and epilepsy (10.8 %). The most common procedures performed were craniotomy and meningioma resection (10.2 %) and acoustic neuroma open resection (7.9 %). The median inflation-adjusted cost of admission did not change over time, with an admission cost value of $12,387 [6,042 - 26,051]. On regression analysis, obstructive hydrocephalus, craniotomy and meningioma resection, acoustic neuroma open resection, and spine tumor resection were all independent predictors of increased cost. CONCLUSION: The care for NF2 patients continues to evolve over time. We report the prevalence of patient demographics, comorbidities, and treatments in the NF2 inpatient population. Further studies are warranted to better understand the risk factors for higher costs, so that patients with NF2 may continue to receive life-long quality care in a cost-effective manner.

In search of the most cost-effective monitoring strategy for vestibular schwannoma: A decision analytical modelling study.

OBJECTIVES: To assess the cost-effectiveness of frequently used monitoring strategies for vestibular schwannoma (VS). DESIGN: A state transition model was developed to compare six monitoring strategies for patients with VS: lifelong annual monitoring; annual monitoring for the first 10 years after diagnosis; scanning at 1-5, 7, 9, 12, 15 years after diagnosis and subsequently every 5 years; a personalised monitoring strategy for small and large tumours; scanning at 1, 2 and 5 years after diagnosis and no monitoring. Input data were derived from literature and expert opinion. Quality-adjusted life years (QALYs) and healthcare costs of each strategy were modelled over lifetime. Net monetary benefits (NMBs) were calculated to determine which strategy provided most value for money. Sensitivity analyses were performed to address uncertainty. RESULTS: Omitting monitoring is least effective with 18.23 (95% CI 16.84-19.37) QALYs per patient, and lifelong annual monitoring is most effective with 18.66 (95% CI 17.42-19.65) QALYs. Corresponding costs were €6526 (95% CI 5923-7058) and €9429 (95% CI 9197-9643) per patient, respectively. Lifelong annual monitoring provided the best value with a NMB of €363 765 (339 040-383 697), but the overall probability of being most cost-effective compared to the other strategies was still only 23%. Sensitivity analysis shows that there is large uncertainty in the effectiveness of all strategies, with largely overlapping 95% confidence intervals for all strategies. CONCLUSIONS: Due to the largely overlapping 95% confidence intervals of all monitoring strategies for VS, it is unclear which monitoring strategy provides most value for money at this moment.

Assessment of costs in open surgery and stereotactic radiosurgery for vestibular schwannomas.

OBJECTIVE: Microsurgical resection and radiosurgery remain the most widely used interventions in the treatment of vestibular schwannomas. There is a growing demand for cost-effectiveness analyses to evaluate these two treatment modalities and delineate the factors that drive their total costs. Here, the authors evaluated specific cost drivers for microsurgical and radiosurgical management of vestibular schwannoma by using the Value Driven Outcomes system available at the University of Utah. METHODS: The authors retrospectively reviewed all cases involving microsurgical and radiosurgical treatment of vestibular schwannomas at their institution between November 2011 and September 2017. Patient and tumor characteristics, subcategory costs, and potential cost drivers were analyzed. RESULTS: The authors identified 163 vestibular schwannoma cases, including 116 managed microsurgically and 47 addressed with stereotactic radiosurgery (SRS). There were significant differences between the two groups in age, tumor size, and preoperative Koos grade (p < 0.05), suggesting that indications for treatment were markedly different. Length of stay (LOS) and length of follow-up were also significantly different. Facility costs were the most significant contributor to both microsurgical and SRS groups (58.3% and 99.4%, respectively); however, physician professional fees were not specifically analyzed. As expected, microsurgical treatment resulted in an average 4-fold greater overall cost of treatment than for SRS cases (p < 0.05), and there was a greater variation in costs for open cases as well. Costs remained stable over time for both open resection and SRS. Multivariable analysis showed that LOS (ß = 0.7, p = 0.0001), discharge disposition (ß = 0.2, p = 0.004), nonserviceable hearing (ß = 0.1, p = 0.02), and complications (ß = 0.2, p = 0.005) affected cost for open surgery, whereas no specifically examined factor could be identified as driving costs for SRS. CONCLUSIONS: This analysis identified the fact that facility utilization constitutes the majority of total costs for both microsurgery and SRS treatment modalities of vestibular schwannomas. LOS, discharge disposition, nonserviceable hearing, and complications contributed significantly to the total costs for the microsurgical group, whereas none of the factors could be identified as driving total costs for the SRS group. This information may be used to establish policies and protocols to reduce facility costs, with the goal of decreasing the total costs without jeopardizing patient care.

Audiologist-led screening of acoustic neuromas in patients with asymmetrical sensorineural hearing loss and/or unilateral tinnitus: our experience in 1126 patients.

OBJECTIVE: To determine whether patients within an otolaryngology department presenting with asymmetrical sensorineural hearing loss and/or unilateral tinnitus can be safely and cost-efficiently screened for acoustic neuroma by audiologists as a first or only point of contact. METHODS: A prospective case series and cost analysis were conducted at a tertiary referral centre. Between April 2013 and March 2017, 1126 adult patients presented to the audiology department with asymmetrical sensorineural hearing loss and/or unilateral tinnitus. All were screened for acoustic neuroma with magnetic resonance imaging, based on pre-determined criteria. The main outcome measure was the presence of acoustic neuroma or other pathology on magnetic resonance imaging. RESULTS: Twenty-five patients (2.22 per cent) were found to have an acoustic neuroma (size range: 3-20 mm) and were referred to the otolaryngologist for further assessment. The remaining patients were appropriately managed and discharged by the audiologists without ENT input. This resulted in an overall cost saving of £164 850. CONCLUSION: Patients with asymmetrical sensorineural hearing loss and/or unilateral tinnitus can be safely screened for acoustic neuroma and independently managed by audiologists as a first or only point of contact, resulting in considerable departmental cost savings.

A standardised pathway for the surveillance of stable vestibular schwannoma.

Introduction Conservative management of patients with a stable vestibular schwannoma (VS) places a significant burden on National Health Service (NHS) resources and yet patients' surveillance management is often inconsistent. Our unit has developed a standardised pathway to guide surveillance imaging of patients with stable VS. In this article, we provide the basis for our imaging protocol by reviewing the measurement, natural history and growth patterns of VS, and we present a cost analysis of implementing the pathway both regionally and nationally. Methods Patients with an extrameatal VS measuring ≤20mm in maximal diameter receive magnetic resonance imaging (MRI) six months after their index imaging, followed by three annual MRI scans, two two-year interval MRI scans, a single three-year interval MRI scan and then five-yearly MRI scans to be continued lifelong. Patients with purely intrameatal tumours follow the same protocol but the initial six-month imaging is omitted. A cost analysis of the new pathway was modelled on our unit's retrospective data for 2015 and extrapolated to reflect the cost of VS surveillance nationally. Results Based on an estimation that imaging surveillance would last approximately 25 years (+/- 10 years), the cost of implementing our regional surveillance programme would be £151,011 per year (for 99 new referrals per year) and it would cost the NHS £1,982,968 per year if implemented nationally. Conclusions A standardised surveillance pathway promotes safe practice in the conservative management of VS. The estimated cost of a national surveillance programme compares favourably with other tumour surveillance initiatives, and would enable the NHS to provide a safe and economical service to patients with VS.

Potential savings in the diagnosis of vestibular schwannoma.

INTRODUCTION: Magnetic resonance imaging (MRI) is used to screen patients at risk for vestibular schwannoma (VS). These MRIs are costly and have an extremely low yield; only 3% of patients in the screening population has an actual VS. It might be worthwhile to develop a test to predict VS and refer only a subset of all patients for MRI. OBJECTIVE: To examine the potential savings of such a hypothetical diagnostic test before MRI. DESIGN: We built a decision analytical model of the diagnostic strategy of VS. Input was derived from literature and key opinion leaders. The current strategy was compared to hypothetical new strategies, assigning MRI to the following: (i) all patients with pathology, (ii) all patients with important pathology and (iii) only patients with VS. This resulted in potential cost savings for each strategy. We conducted a budget impact analysis to predict nationwide savings for the Netherlands and the United Kingdom (UK), and a probabilistic sensitivity analysis to address uncertainty. RESULTS: Mean savings ranged from €256 (95%CI €250 - €262) or approximately US$284 (95%CI US$277 - US$291) per patient for strategy 1 to €293 (95%CI €290 - €296) or approximately US$325 (95%CI US$322 - US$328) per patient for strategy 3. Future diagnostic strategies can cost up to these amounts per patient and still be cost saving. Annually, for the Netherlands, €2.8 to €3.2 million could be saved and €10.8 to €12.3 million for the UK. CONCLUSIONS: The model shows that substantial savings could be generated if it is possible to further optimise the diagnosis of VS.

Cost analysis of vestibular schwannoma screening with contrast-enhanced magnetic resonance imaging in patients with asymmetrical hearing loss.

BACKGROUND: Vestibular schwannomas are a rare cause of asymmetrical hearing loss, and routine screening with magnetic resonance imaging can be costly. This paper reports results on vestibular schwannoma screening at our institution and compares the cost of screening to a utility of hearing benefit. METHOD: All screening examinations with magnetic resonance imaging performed for asymmetrical hearing loss between 2006 and 2011 were retrospectively reviewed. The cost per new vestibular schwannoma diagnosis was calculated. The cost per patient for those who benefitted from intervention was estimated based on rates of hearing preservation reported in the literature. RESULTS: Forty-five (4.3 per cent) of 1050 screening examinations with magnetic resonance imaging performed for asymmetrical hearing loss were positive for vestibular schwannoma, and the cost per new diagnosis was $11,436. The estimated screening cost per patient for those who benefitted from surgery or radiation was $147,030, while US federal compensation for unilateral hearing loss was $44,888. CONCLUSION: Although we achieved a lower screening cost per new diagnosis than reported in the current literature, there remains disparity between the screening cost per benefitted patient and the 'benefit' of hearing.

A cost comparative study of Gamma Knife radiosurgery versus open surgery for intracranial pathology.

Resection is the traditional treatment for common intracranial pathologies including brain metastases, arteriovenous malformations (AVM), and acoustic neuromas. However, more recently Gamma Knife radiosurgery (GKRS; Elekta AB, Stockholm, Sweden) has emerged as an effective, alternative treatment modality. There are limited data investigating the cost effectiveness of these two treatment modalities. In this study, we compare the costs of GKRS and open surgical excision. This was a retrospective study including all patients at a single-institution across a 3 year period with at least 12 months of post-resection follow-up for brain metastases, acoustic neuromas, or AVM. The costs of care were then totaled and compared to known average costs for GKRS at the same institution. The average 12 month costs of treating patients with brain metastases, acoustic neuromas, and AVM using open surgery were USD$55,938, $67,538, and $78,332, respectively. The average 12 month costs of treating brain metastases, acoustic neuromas, and AVM with GKRS were USD$23,069, $37,840, and $46,293, respectively. This shows that GKRS was on average 58.8%, 44.0%, and 40.9% of the cost of open surgery for brain metastases, acoustic neuromas, and AVM, respectively. GKRS is a cost effective, first-line, alternative to open surgery for treatment of brain metastatic lesions, acoustic neuromas, and AVM in selected patients. This result conforms to previous studies, which also demonstrate that radiosurgery is the more cost-effective treatment for brain metastases and acoustic neuromas when patients are well suited for either approach. Further prospective studies are needed to show that this result is valid at other institutions.

Cost-effective analysis of unilateral vestibular weakness investigation.

OBJECTIVES: To evaluate the cost-effectiveness of obtaining a magnetic resonance imaging (MRI) in patients with abnormal electronystagmography (ENG) or videonystagmography (VNG) results. STUDY DESIGN: Retrospective chart review. SETTINGS: Academic specialty center. PATIENTS: Patients presenting with vertigo between January 1, 2010, and August 30, 2013. METHODS: Patients who fit the following abnormal criteria were included in the study: unilateral caloric weakness (≥20%), abnormal ocular motor testing, and nystagmus on positional testing. Patients with abnormal findings who then underwent MRI with gadolinium were evaluated. RESULTS: Of the 1,996 charts reviewed, there were 1,358 patients who met the inclusion criteria. The average age of these patients was 62 years (12-94 yr). The male:female ratio was approximately 1:2. Of the 1,358 patients, 253 received an MRI with the following pathologies: four vestibular schwannomas, three subcortical/periventricular white matter changes suspicious for demyelinating disease, four acute cerebellar/posterior circulation infarct, two vertebral artery narrowing, one pseudomeningocele of internal auditory canal, and two white matter changes indicative of migraines. The positive detection rate on MRI was 5.5% based on MRI findings of treatable pathologies causing vertigo. Average cost of an MRI is $1,200, thereby making the average cost of identifying a patient with a positive MRI finding $15,180. CONCLUSION: In our study, those patients with a positive MRI had a constellation of symptoms and findings (asymmetric sensorineural hearing loss, tinnitus, vertigo, and abnormal ENG/VNG). Cost-effectiveness can be improved by ordering an MRI only when clinical examination and VNG point toward a central pathology. Clinical examination and appropriate testing should be factored when considering the cost-effectiveness of obtaining an MRI in patients with abnormal ENG/VNG findings.

Trends in demographics, charges, and outcomes of patients undergoing excision of sporadic vestibular schwannoma.

OBJECTIVE: To assess demographics, charges, and outcome measures by temporal and volume analysis in the treatment of vestibular schwannoma. DESIGN: Cross-sectional analysis. SETTING, SUBJECTS, AND METHODS: The California Hospital Inpatient Discharge Databases from 1996 to 2010. RESULTS: A total of 6545 cases from 1996 to 2010 were identified. Of these, 86.2% occurred at high-volume centers (HVCs), and the number of annual cases decreased by 28.5%. Patients presenting for surgery were increasingly younger, non-Caucasian, and likely to have comorbidities. Total charges significantly increased over time (P < .001), with the median total charge in 2006-2010 being $91,338 compared with $38,607.92 in 1996-2000 after adjusting for inflation. Routine discharges (home or residence) were more likely at HVCs (odds ratio [OR] 5.48, P < .001) and less likely if patients had Medicaid (Medi-Cal; OR 0.51, P = .002) or Medicare (OR 0.55, P = .022), were 65 years or older (OR 0.56, P = .025), or had comorbidities (OR 0.54, P < .001). Shorter hospital stays were more likely at HVCs (OR 3.77, P < .001) and less likely if patients had Medicaid (OR 0.36, P < .001) or comorbidities (OR 0.61, P < .001). Lesser total charges were more likely at HVCs (OR 2.12, P = .002) and less likely if patients had comorbidities (OR 0.70, P < .001). Mortality was less likely at HVCs (OR 0.10, P = .011). CONCLUSION: The profile of patients undergoing vestibular neuroma excision is changing. Surgical volume is decreasing, suggesting a trend toward more conservative management or stereotactic radiation. Patients are best served at HVCs, where routine discharges, shorter length of stay, decreased mortality, and lower total charges are more likely.

Conservative management, surgery and radiosurgery for treatment of vestibular schwannomas: a model-based approach to cost-effectiveness.

OBJECTIVE: To undertake a cost-effectiveness analysis comparing conservative management, surgery and radiosurgery for treating small-to-medium (1-20 mm)-sized vestibular schwannomas. DESIGN: Model-based economic evaluation using individual-level data from a Birmingham-based longitudinal patient database and from published sources. Both a decision tree and state-transition (Markov) model were developed, from an National Health Service (NHS) perspective. Sensitivity analyses were also carried out. SETTING: Secondary care treatment for patients with small-to-medium-sized vestibular schwannomas. PARTICIPANTS: Three hypothetical cohorts of adult patients receiving conservative management, radiosurgery or surgery treatment, aged 58 years as starting age within model. MAIN OUTCOME MEASURES: Cost-effectiveness based on cost per quality-adjusted life year (QALY). RESULTS: Conservative management is the preferred strategy for the treatment of small-to-medium-sized vestibular schwannomas. Conservative management is both cheaper (-£ 722 and -£ 2764) and more effective (0.136 and 0.554 quality-adjusted life years) than both radiosurgery and surgery, respectively. A conservative strategy can therefore be considered as highly cost-effective. This result is sensitive to the assumed quality-of-life parameters in the model. Sensitivity analysis suggests that the probability of a conservative strategy being the most cost-effective approach compared with surgery and radiosurgery at a willingness to pay of £ 20 000/quality-adjusted life year gained is 80% and 55%, respectively. CONCLUSIONS: A conservative approach is the preferred strategy for treatment of small-to-medium vestibular schwannomas. This result is sensitive to quality-of-life values used in the analysis. More research is required to assess the impact of treatment upon patients' health-related quality of life over time.

Surgery is cost-effective treatment for young patients with vestibular schwannomas: decision tree modeling of surgery, radiation, and observation.

OBJECT: Vestibular schwannomas (VSs) are managed in 3 ways: observation ("wait and scan"); Gamma Knife surgery (GKS); or microsurgery. Whereas there is considerable literature regarding which management approach is superior, there are only a few studies addressing the cost of treating VSs, and there are no cost-utility analyses in the US to date. METHODS: In this study, the authors used the University of California at San Francisco medical record and hospital accounting databases to determine total hospital charges and costs for 33 patients who underwent open surgery, 42 patients who had GKS, and 12 patients who were observed between 2010 and 2013. The authors then performed decision-tree analysis to determine which treatment paradigm produces the highest quality-adjusted life years and to calculate the incremental cost-effectiveness ratio, depending on the patient's age at VS diagnosis. RESULTS: The average total hospital cost over a 3-year period for surgically treated patients was $80,074 (± $49,678) versus $9737 (± $5522) for patients receiving radiosurgery and $1746 (± $2792) for patients who were observed. When modeling the most debilitating symptoms and worst outcomes of VSs (vertigo and death) at different ages at diagnosis, radiation is dominant to observation at all ages up to 70 years. Surgery is cost-effective when compared with radiation (incremental cost-effectiveness ratio < $150,000) at younger ages at diagnosis (< 45 years old). CONCLUSIONS: In this model, surgery is a cost-effective alternative to radiation when VS is diagnosed in patients at < 45 years. For patients ≥ 45 years, radiation is the most cost-effective treatment option.

The impact of comorbidities, regional trends, and hospital factors on discharge dispositions and hospital costs after acoustic neuroma microsurgery: a United States nationwide inpatient data sample study (2005-2009).

OBJECT: Hospitalization cost and patient outcome after acoustic neuroma surgery depend on several factors. There is a paucity of data regarding the relationship between demographic features such as age, sex, race, insurance status, and patient outcome. Apart from demographic factors, there are several hospital-related factors and regional issues that can affect outcomes and hospital costs. To the authors' knowledge, no study has investigated the issue of regional disparity across the country in terms of cost of hospitalization and discharge disposition. METHODS: The authors analyzed the Nationwide Inpatient Sample (NIS) database over the years 2005-2009. Several variables were analyzed from the database, including patient demographics, comorbidities, and surgical complications. Hospital variables, such as bedsize, rural/urban location, teaching status, federal or private ownership, and the region, were also examined. Patient outcome and increased hospitalization costs were the dependent variables studied. RESULTS: A total of 2589 admissions from 242 hospitals were analyzed from the NIS data over the years 2005-2009. The mean age was 48.99 ± 13.861 years (± SD), and 304 (11.7%) of the patients were older than 65 years. The cumulative cost incurred by the hospitals from 2005 to 2009 was $948.77 million. The mean expenditure per admission was $76,365.09 ± $58,039.93. The mean total charges per admission rose from $59,633.00 in 2005 to $97,370.00 in 2009. The factors that predicted most significantly with other than routine (OTR) disposition outcome were age older than 65 years (OR 2.22, 95% CI 1.411-3.518; p < 0.001), aspiration pneumonia (OR 16.085, 95% CI 4.974-52.016; p < 0.001), and meningitis (OR 11.299, 95% CI 3.126-40.840; p < 0.001). When compared with patients with Medicare and Medicaid, patients with private insurance had a protective effect against OTR disposition outcome. Higher comorbidities predicted independently for OTR disposition outcome (OR 1.409, 95% CI 1.072-1.852; p = 0.014). The West region predicted negatively for OTR disposition outcome. Large hospitals were independently associated with higher hospital charges (OR 4.269, 95% CI 3.106-5.867; p < 0.001). The West region had significantly higher (p < 0.001) mean hospital charges than the other regions. Patient factors such as meningitis and aspiration pneumonia were strong independent predictors of increased hospital charges (p < 0.001). Higher comorbidities (OR 1.297, 95% CI 1.036-1.624; p = 0.023) and presence of neurofibromatosis Type 2 (OR 2.341, 95% CI 1.479-3.707; p < 0.001) were associated with higher hospital charges. CONCLUSIONS: The authors' study shows that several factors can affect patient outcome and hospital charges for patients who have undergone acoustic neuroma surgery. Factors such as younger age, higher ZIP code income, less comorbidity, private insurance, elective surgery, and the West region predicted for better disposition outcome. However, the West region, higher comorbidities, and weekend admissions were associated with higher hospitalization costs.

Evaluation of cost effectiveness for conservative and active management strategies for acoustic neuroma.

OBJECTIVE: To determine whether economic costs associated with a conservative management strategy for unilateral acoustic neuroma offer an economic advantage over active management options. DESIGN: Cost and sensitivity analysis on a prospective cohort. SETTING: Single centre study within a tertiary referral centre in Toronto, Canada. PARTICIPANTS: 72 patients (32 males, 40 females) aged 36 to 78 years with unilateral acoustic neuroma were assigned initially to a conservative management strategy. Entry criteria were small tumour size (less than 15 mm in the cerebellopontine angle), patient preference and/or significant co-morbidity. INTERVENTIONS: MRI scanning was performed every 6 months for the first year, annually subsequently and then every 2-3 years as required. Clinical review occurred every 6 months. Failure of conservative management led to active treatment. MAIN OUTCOME MEASURES: Cost analysis was performed to determine the mean total cost per patient for continued conservative management over the follow up period compared to the mean upfront total cost per patient undergoing active intervention. RESULTS: Cost analysis within the Canadian health care system determined the mean total cost per patient for microsurgical removal at CAD$22,402 (12,545 pounds; 14,561 euros), for gamma knife radiotherapy at CAD$27659 (15,489 pounds; 17,978 euros), for LINAC radiotherapy at CAD$9,003(5,041 pounds; 5,852 euros) and for conservative management at CAD$9,651 (5,405 pounds;6,273 euros) over the follow-up timeframe. CONCLUSION: An economic advantage can be demonstrated for the conservative management of acoustic neuromas compared to microsurgical removal and gamma knife radiotherapy on the proviso that no increase in active treatment complications arose from continued tumour growth during the period of observation.

The role of magnetic resonance imaging in the identification of suspected acoustic neuroma: a systematic review of clinical and cost effectiveness and natural history.

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.

Comparison of the surgical and follow-up costs associated with microsurgical resection and stereotactic radiosurgery for vestibular schwannoma.

OBJECT: The best approach to the management of vestibular schwannoma (VS) remains controversial. The aim of this study is to analyze the initial and follow-up costs of resection and stereotactic radiosurgery for patients with VS. METHODS: Initial and follow-up costs in 53 cases in which patients with unilateral, previously unoperated VSs > 3 cm underwent resection (21 cases) or radiosurgery (32 cases) at the Mayo Clinic from June 2000 until July 2002 were analyzed for 36 months. Follow-up treatment-specific utilization records were gathered prospectively for patients not returning to the Mayo Clinic after treatment. Six-month moving averages of incremental follow-up costs were calculated for the 2 patient groups. RESULTS: The mean cost of surgery in the microsurgery group was $23,788 (95% confidence interval $22,280-$24,842) compared with $16,143 (95% confidence interval $15,277-$17,545) for the radiosurgical group. Mean incremental follow-up costs per month for patients in the microsurgery group started just > $1,000 per month, decreased steadily, and remained < $70 per month by the 10th month of follow-up. Mean incremental follow-up costs per month for patients in the radiosurgery group were <$10 per month for the first few months and thereafter increased to as much as $200 per month. CONCLUSIONS: Although the total cost of microsurgery is higher due to the costs of hospitalization, follow-up costs for radiosurgery are greater in general. From a societal perspective, radiosurgery is less expensive than microsurgical resection provided that the rate of tumor progression after radiosurgery remains low with long-term follow-up.

The stacked ABR: a sensitive and specific screening tool for detecting small acoustic tumors.

The failure of standard ABR measures to detect small (< or =1 cm) acoustic tumors has led to the use of enhanced magnetic resonance imaging (MRI) as the standard to screen for small tumors. This study investigates the suitability of the stacked ABR as a sensitive screening alternative to MRI for small acoustic tumors (SATs). The objective of the study was to determine the sensitivity and specificity of the stacked ABR technique for detecting SATs. A total of 54 patients with acoustic tumors identified by MRI that were either < or =1 cm in size or undetected by standard ABR methods, irrespective of size, were studied. A control population of 78 nontumor normal-hearing subjects was also tested. For comparison, two standard ABR measures (IT5 and I-V delay) were also analyzed. The stacked ABR demonstrated 95% sensitivity and 88% specificity; 100% sensitivity was obtained at 50% specificity. Standard ABR measures were much poorer in detecting these tumors. In conclusion, the stacked ABR can be used as a sensitive, widely-available, cost-effective, and comfortable tool for screening SATs.