Magnetic resonance imaging: a cost-effective first line investigation in the detection of vestibular schwannomas

Cost of Vestibular Schwannoma Treatment: A Systematic Review and Meta-Analysis

Introduction  Research furthering treatment efficacy for microsurgical resection and stereotactic radiosurgery for vestibular schwannoma (VS) is ever-growing; however, there remains a paucity of research addressing treatment costs. Our aim is to define the reported costs of different treatment modalities used for VS. Methods  A systematic review of the literature for VS treatment cost was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using PubMed and Web of Science databases. Literature that presented cost of VS treatment specific to the modality was included. Articles from 1990 to present day in English were considered. Cost was corrected for inflation to April 2022 dollars using the US Bureau of Labor Statistics Inflation Calculator. Results  A total of 407 articles were included in the analysis. After review, eight articles provided data on cost of treatment. In total, 687 patients were included across seven studies, with study dates ranging from 1997 to 2020. The average cost of resection was $54,321.99 (range = $10,243-95,590, n  = 8), radiosurgery $27,837.92 (range = $6,281-51,676, n  = 6), and observation $6,304.88 (range = $2,149-11,886, n  = 3). Conclusion  Our findings describe the limited and significant variability of data on published costs for the treatment of VS. Given the relative clinical equipoise between treatment modalities in some scenarios, better understanding of this end-point will help physicians make more responsible recommendations in the resource-constrained environment of modern healthcare and this analysis should serve as a starting point for more robust analysis into cost-effectiveness of treatment for VS.

Primary tumors of the facial nerve misdiagnosed: a case series and review of the literature

CONCLUSION

Unusual primary tumors of the facial nerve should be considered in patients with progressive facial paralysis, especially if this is accompanied by hearing loss or vertigo. Misdiagnosis could increase the difficulties of operation, diminish the chance of facial nerve reconstruction, and increase the likelihood of poor reconstructive outcomes.

OBJECTIVE

This paper was to determine the characteristics of facial nerve primary tumors misdiagnosed as tumor-free conditions many years prior, and to describe appropriate treatments.

METHODS

The cases of 11 Chinese patients with misdiagnosed primary tumors of the facial nerve were reviewed; every one had been misdiagnosed for more than 8 years. All patients presented with progressive or complete facial paralysis and hearing loss, with or without vertigo. The pre- and post-operative images (including CT scans of the temporal bone) and MRI data were reviewed.

RESULTS

All tumors were completely resected using the translabyrinthine or transmastoid approach and were confirmed to be primary tumors of the facial nerve. Facial-hypoglossal nerve anastomosis failed because fibrosis developed at the end of the facial nerve in one patient whom this study sought to manage in two stages. One patient accepted facial-hypoglossal nerve anastomosis of two-stage and patient status improved to House-Brackmann (H-B) grade V from H-B grade VI. The other nine patients chose not to undergo reconstruction.

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.

Magnetic resonance imaging screening in acoustic neuroma

OBJECTIVES

Magnetic resonance imaging (MRI) is the definitive investigation for detection of an acoustic neuroma. It is however an expensive resource, and pick-up rate of a tumor can be as low as 1% of all patients scanned. This study aims to examine referral patterns for MRI screening for patients presenting with asymmetrical sensorineural hearing loss (ASHL). A second aim was to suggest appropriate screening criteria.

METHOD

All 132 MRI scans performed for ASHL in the year 2005 were reviewed retrospectively along with their case records and audiograms. In addition, MRI scans and case records were reviewed for the last 30 patients diagnosed with acoustic neuromas. Information was analyzed using 2 published protocols and additional frequency-specific defined criteria.

RESULTS

Two acoustic neuromas were picked up out of 132 scans performed. Of the scans performed for ASHL, a third did not fit with any of the published criteria. Of the 30 positive scans for a tumor, the patients/audiograms revealed that 10% did not fit the published criteria despite the patients having no other audiovestibular symptoms.

CONCLUSIONS

There appears to be no universally accepted guidelines on screening in ASHL with clinical acumen being used by most ENT consultants in this region. Applying protocols may reduce the amount of scans performed, but up to 10% of tumors may be missed by this approach.

A clinical, genetic and audiological study of patients and families with unilateral vestibular schwannomas. II. Audiological findings in 93 patients with unilateral vestibular schwannomas

Ninety-three patients with histolofically or radiolofically confiemd unilateral vestibular schwannomas were recruited. Audiological testing for retrocochelar pathology was undertaken. Patients' hospital records were examined for previous audiological and radiological results.

The audiometric configuration was designated as one of the following normal, sloping, low frequency, peak, through or falt. A sloping sensorneural audiometric configuration was present in 68 pec cent of cases. No significant correlation was found between tumour size and average pure tone threshold 500 HZ to 4000 HZ, optimum discrimination score or interaural differences for wave V. Ninety-one per cent of cases had abnoramalities on auditory evoked potential; 92 per cent of cases showed abnormalities on stapedial reflex testing.

The limitations of audiologica testing in the investigation of patients with suspected unilateral vestibular schwannomas are discussed. A protocol for the investigation of such patients is presented.

Molecular genetic analysis of the NF2 gene in young patients with unilateral vestibular schwannomas

Neurofibromatosis type 2 (NF2) must be suspected in patients presenting with a unilateral vestibular schwannoma at a young age who are therefore at theoretical risk of developing bilateral disease. We identified 45 patients aged 30 years or less at the onset of symptoms of a unilateral vestibular schwannoma. Molecular genetic analysis of the NF2 gene was completed on peripheral blood samples in all 45 and on 28 tumour samples. No pathogenic NF2 mutations were identified in any of the blood samples. NF2 point mutations were identified in 21/28 (75%) tumour samples and loss of heterozygosity (LOH) in 21/28 (75%) tumour samples. Both mutational hits were identified in 18/28 (65%) tumour samples. In one multilobular tumour, one (presumably first hit) mutation was confirmed which was common to different foci of the tumour, while the second mutational event differed between foci. The molecular findings in this patient were consistent with somatic mosaicism for NF2 and the clinical diagnosis was confirmed with the presence of two meningiomas on a follow up MRI scan. A further patient developed a contralateral vestibular schwannoma on a follow up MRI scan in whom neither of the truncating mutations in the vestibular schwannoma were present in blood. It is important when counselling patients with unilateral vestibular schwannomas to identify (1) those at risk of bilateral disease, (2) those at risk of developing other tumours, and (3) other family members at risk of developing NF2. Comparing tumour and blood DNA cannot exclude mosaicism in the index case and cannot, therefore, be used to predict those at risk of developing further tumours. However, identification of both mutations or one mutation plus LOH in the tumour and exclusion of those mutations in the blood samples of the sibs or offspring of the affected case may be sufficient to render further screening unnecessary in these relatives.

[Magnetic resonance: first choice test in the screening of internal auditory canal and cerebellopontine angle tumors]

Although internal auditory canal (IAC) and cerebellopontine angle (CPA) tumors are rare, their clinical suspicion is quite common in the otolaryngology office. MRI is the imaging modality of choice in diagnosing these tumors. Perceived high costs may prevent clinicians from using it as a screening tool. A protocol designed to improve cost-effectiveness in such diagnosis results in a more rationale clinical practice. Our aim was to evaluate the usefulness of MRI as screening tool in diagnosis of IAC and CPA tumors in our population. Between March 1998 and March 2000, a prospective series of 200 cases had a MRI screening requested. MRI were performed following Fast Spin Echo technique, providing T2-weighted images. Gadolinium enhanced MRI was reserved for selected cases. We report on 190 MRI done. We found 7 neuromas (3.5%), one CPA metastasis, one epidermoid cyst and 9 IAC vascular anomalies. Only 138 cases (69%) had normal MRI images. When used following a designed protocol, MRI is our procedure of choice while screening IAC and CPA tumors because it is a cost-effective tool.

MRI screening for acoustic neuroma: a comparison of fast spin echo and contrast enhanced imaging in 1233 patients

Gadolinium enhanced MRI is the gold standard investigation for the detection of acoustic neuroma. Non-contrast MRI sequences have been suggested as an alternative for screening examinations. In order to determine the utility of fast spin echo imaging, both gadolinium enhanced T1 weighted images and fast spin echo T2 weighted images were acquired in 1233 consecutive patients referred for exclusion of acoustic neuroma. Two radiologists independently recorded their findings. Fast spin echo T2 weighted images were evaluated with respect to the visibility of nerves within the internal auditory canals and allocated a confidence score for the presence or absence of acoustic neuroma. 33 acoustic neuromas were identified. Only 56% were confidently identified on fast spin echo T2 weighted images alone; gadolinium enhanced T1 weighted images were required to confirm the diagnosis in 44% of the cases, including 9 of the 10 intracanalicular tumours. However, when identification of two normal intracanalicular nerves is employed as the criterion of normality, the single fast spin echo T2 weighted sequence excluded acoustic neuroma in 59% of this screened population. It is concluded that an imaging strategy intended to identify small intracanalicular acoustic neuromas cannot rely on fast spin echo T2 weighted imaging alone. Gadolinium enhanced T1 weighted imaging could be restricted to patients where fast spin echo images do not exclude acoustic neuroma but this strategy requires continuous supervision by an experienced radiologist. In most practices the screening examination should continue to include a gadolinium enhanced sequence in order to optimize the detection of small acoustic neuromas.

Outcome of using magnetic resonance imaging as an initial screen to exclude vestibular schwannoma in patients presenting with unilateral tinnitus

The improved cost-effectiveness of gadolinium-enhanced magnetic resonance imaging (MRIg) as a diagnostic tool for vestibular schwannoma has resulted in smaller tumours being diagnosed. There has been a change in the clinical presentation of these tumours and up to four per cent may present with unilateral tinnitus. The limitation of auditory brain stem response (ABR) as a screening tool that detects small tumours is recognized and there is a strong argument for using MRIg as the initial investigation. Various screening guidelines have been proposed, some include submitting patients with unilateral tinnitus for MRIg. This report describes the findings in a group of 174 patients presenting with unilateral tinnitus who underwent MRIg as part of a guideline-directed screen to exclude vestibular schwannoma. Five patients had a cause for their tinnitus diagnosed, one a vestibular schwannoma. Two had intracranial aneurysms and another three had pathology revealed that merited onward referral. A further nine patients had incidental findings that neither accounted for their symptoms nor needed further investigation or referral. The rationale for screening these patients with MRIg is discussed.

Audit of regional screening guidelines for vestibular schwannoma

An audit of 334 patients who underwent magnetic resonance imaging (MRI) as investigation for a possible diagnosis of vestibular schwannoma was carried out to assess adherence to previously agreed screening guidelines. This represents one year's activity. A posterior fossa tumour was identified in 12 patients. Scan requests were judged to be inappropriate for 28 cases. The issues surrounding the screening for acoustic neuroma are discussed.

Economic analyses of radiological procedures: a methodological evaluation of the medical literature

OBJECTIVE

Increasing pressure to curb health care costs has led to considerable interest in economic analyses, including both cost-effectiveness and cost-benefit analyses. Numerous economic analyses of radiological procedures have appeared in both the radiology and non-radiology literature. The objective of this study was to evaluate the methodological quality of economic analyses of radiological procedures published in the non-radiology medical literature during the years 1990 1995.

METHODS

Original investigations from the medical (non-radiological) literature that include economic analyses of radiological interventions were identified from a computerized literature search. Each economic analysis article was evaluated by two independent reviewers for adherence to ten methodological criteria. The criteria were derived from review of the medical and radiological economic analysis methodology literature and consisted of the following: (1) Comparative options stated; (2) perspective of analysis defined; (3) outcome measure identified; (4) cost data included; (5) source of cost data stated; (6) long term costs included; (7) discounting employed; (8) summary measure provided; (9) incremental computation method used; and (10) sensitivity analysis performed. The results were compared to a previous study that evaluated the radiological literature.

RESULTS

Of the 56 articles in the medical literature that included economic analyses of radiological procedures, only eight (14%) conformed to all ten methodological criteria. The cost data (98%) and comparative options (89%) criteria exhibited high compliance, while the perspective of analysis (25%) and discounting (32%) criteria had relatively low compliance. Agreement between the reviewers was excellent (kappa = 0.88).

CONCLUSIONS

Published economic analyses of radiology procedures usually do not meet accepted methodological standards.

A cost effective screening protocol for vestibular schwannoma in the late 90s

Magnetic resonance imaging (MRI) is the imaging modality of choice in diagnosing vestibular schwannoma (VS). Perceived high costs have prevented clinicians from using it as a screening investigation, although MR scanners are now widely available in the United Kingdom. In a retrospective study, the clinical records of all the patients who presented to the ENT department of Taunton and Somerset NHS Trust with suspected symptoms of VS during the year 1994 were analysed. The cost of confirming or refuting the diagnosis of VS in each patient ranged from 220.72 pounds to 580.31 pounds depending on the number of hospital visits and investigations performed. This study shows that the routine use of MR scanning for detection of VS is cost effective and more effective than the use of conventional tests.