Magnus Teschner

Cochlear implantation in different health-care systems: disparities between Germany and the United States.

Introduction Cochlear implantation is a popular procedure to restore hearing in patients with severe-to-profound hearing loss. Despite the widespread acceptance of the intervention, many variables exist in the evaluation for and implementation of this technology throughout the world. The primary aim of this investigation is to analyze treatment disparities between Germany and the United States in cochlear implantation. Materials and Methods Cochlear implant recipients in 2 representative cochlear implant centers in the United States and Germany were retrospectively analyzed. Differences in preoperative, perioperative, and postoperative treatment paradigms as well as the disparities in the follow-up were recorded. Objective measures included demographic data, length of hospitalization, minor and major complication rates, and speech scores within the first 3 years. Moreover, a cost analysis comparison between both centers was performed. Results A number of differences in treatment were noted between the two centers. The primary difference was that in Germany the procedure was inpatient with an average 4-day hospital stay, whereas in the United States, it was an outpatient procedure. Despite these differences, only small differences were noted in the category of minor complications, and no differences were seen in the category of major complications between the 2 centers. Comparing the results of monosyllabic speech tests, no major differences could be detected. Cost analysis between the 2 centers demonstrates that, whereas in Germany, all charges are covered by the statutory health insurance, in the United States, the reimbursements are significantly lower than the charges. Discussion Despite differences in the clinical approach to cochlear implants in Germany versus the United States, no significant differences in outcomes were seen in the 2 groups, and the complication rates were nearly identical. Interestingly, although the procedure in Germany is associated with a 4-day hospital stay, the charges for the entire procedure in Germany are approximately ½ as compared with those in the United States, although the actual reimbursement for this procedure may be lower in the United States than in Germany.

Diffusion-Weighted MRI in the Diagnosis of Cholesteatomas

Objective: The diagnosis of a cholesteatoma can be difficult in cases with an intact tympanic membrane. The aim of our study was to examine whether diffusion-weighted MRI can confirm the diagnosis of a cholesteatoma. Study Design: A preoperative diffusion-weighted MRI (echo-planar imaging) scan of the temporal bone was performed in 31 patients with clinically suspected cholesteatoma. The diagnosis was confirmed by pathohistological examination in 18 cases, while the majority of the remaining patients showed chronic otitis media without cholesteatoma. Results: In 3 out of 18 patients with histologically confirmed cholesteatoma, diffusion-weighted imaging produced a hyperintense signal. Another 4 of the 18 cases had a questionable positive result. No increased signal was observed in 11 of these 18 patients. Of 12 patients without a cholesteatoma, 2 showed a positive signal while a questionable hyperintense signal was observed in 5 patients. Conclusions: According to our present findings, diffusion-weighted MRI (echo-planar imaging) can – with a low sensitivity and specificity – be helpful in individual cases in provisionally diagnosing a cholesteatoma in association with standard MRI and high-resolution CT, even though the lack of a hyperintense signal in diffusion-weighted MRI does not exclude a cholesteatoma.

Minimized rotational vestibular testing as a screening procedure detecting vestibular areflexy in deaf children: screening cochlear implant candidates for Usher syndrome type I.

Morbus Usher (USH), a combination of sensorineural hearing loss and retinal visual impairment, is classified into group I–III. USH I patients are born deaf. Within the first 10 years of life, they develop a severe vision impairment due to progressive retinal dystrophy (retinitis pigmentosa). USH I patients show vestibular deficits. The incidence of USH I among congenitally deaf children is assumed to be as high as 10%. We intend to create a simple examination procedure for screening congenitally deaf children for vestibular deficiency and subsequently USH I. The examination procedure is named “Minimized Rotation”. The vestibular function of deaf children was examined by Minimized Rotation during their preoperative cochlear implant candidacy examination. A lack of postrotational nystagmus was seen as an indication for vestibular deficit. Subsequently some of these patients were examined under general anaesthesia by electroretinography (ERG) at the Department of Ophthalmology. A total of 117 children were examined by Minimized Rotation. In 19 children (16.2%) no rotational nystagmus was found. Six of these children were additionally examined at the Department of Ophthalmology using Ganzfeld ERG. Three of them (50%) showed generalized dysfunction of the retina; 8.1% of the children undergoing preoperative evaluation for cochlear implatation are assumed to show abnormalities of the retina. Rotational examination seems to be an appropriate screening method to detect vestibular deficits, which is one sign of USH I. The results always have to be verified by Ganzfeld-ERG or further genetic investigations. Children with USH I are threatened by progressive reduction of vision. We, therefore, consider USH I children always to be implanted bilaterally with a cochlear implant to maximize the benefit of auditory rehabilitation.

Comparison of two different titanium couplers for an active middle ear implant.

Objective To compare surgical methods, functional gain, and speech discrimination using two different coupling methods for an active middle ear implant. Of several couplers enabling placement of the active element at various locations, two function directly at a cochlear membrane, bypassing a missing or malformed ossicular chain. This study evaluates whether either of these methods is more beneficial. Study design Retrospective case review. Setting ENT surgical clinic. Patients Forty-seven German-speaking patients with moderate to severe mixed hearing loss. Interventions Records of patients implanted with either a round window (RW) or oval window (OW) coupler and active implant were examined. Preoperative and postoperative bone and air-conduction thresholds, auditory gain, and speech perception were compared. Main outcome measures Functional gain, Freiburger monosyllables in quiet. Results The range of hearing benefit shown by functional gain in patients implanted with the RW coupler (median) was between 22.5 dB (at 0.25 kHz) and 52.5 dB (2 and 3 kHz). In the OW group, improvement was similar, ranging from 21 dB (at 8 kHz) to 50 dB (1 and 2 kHz). Patients in both groups showed a similar improvement in speech recognition. Median preoperative unaided word recognition was 0% at 60 dB HL for both patient groups, improved postoperatively in both groups to median 85% correct at 65 dB HL and 95% at 80 dB HL. Conclusion Placement of an active middle ear implant using the RW and the OW coupler was found to be safe, although the surgical methods differ. Safety and efficacy of both couplers present no significant differences.

Validity of Cochlear Microphonics at High Sound Pressure Levels as an Important Clinical Aspect

Introduction: Cochlear microphonics are electrical stimulus responses of the inner ear, generated by mechanical displacement of the hair cells caused by acoustic stimulation. As cochlear microphonics are often used in the diagnosis of hearing impairment and deafness, in preliminary investigations it was seen that obliteration or ossification have no effect on the extent to which cochlear microphonics can be recorded at high sound pressure levels. As artifacts at high sound pressure levels suggested, measurements were subsequently conducted using temporal bone specimens. Methods: In a test setup equivalent to that for electrocochleography, a needle electrode was placed on the cochlear promontory and used to record potentials following application of an acoustic stimulus. Results: Curves comparable to cochlear microphonics were registrable down to a threshold of 80 dB HL. Additional measurements conducted on damp cloths yielded comparable findings. Conclusions: Registration of cochlear microphonics at high sound pressure levels does not serve as an indicator of hair cell function, but should instead be regarded as artifacts. The possible sources are discussed.

The influence of post-meningitic obliteration and ossification of the cochlea on cochlear microphonics

Cochlear microphonics are electrical stimulus responses of the inner ear. They are generated by mechanical displacement of the hair cells caused by acoustic stimulation and can be recorded from the cochlear promontory via a needle electrode. In individuals with post-meningitic deafness, fibrous obliteration or ossification of the cochlea may occur. The aim of the present investigation was to establish whether obliteration or ossification leads to any alteration in the extent to which cochlear microphonics can be recorded (as compared with that in patients with a fluid-filled cochlea whose deafness was not post-meningitic), as an indication of changes in the mechanical displacement of the remaining hair cells. Cochlear microphonics in 15 individuals with proven obliteration or ossification of the cochlea were compared with those in 15 control subjects (deaf individuals whose hearing loss was not post-meningitic, and who had a fluid-filled cochlea). Our findings reveal no statistically significant differences between the two groups in the degree to which cochlear microphonics can be recorded. This study does not demonstrate evidence of a change in this property due to ossification or obliteration of the cochlea.

[Tuberculous Otitis media - a rare differential diagnosis in Germany].

A 28-year-old female patient with a migrant background presented for surgery with a suspected cholesteatoma in the left ear. The patient reported having had an aural discharge for several months; otoscopic examination revealed a runny ear, and discrete granulation tissue was seen. Pure-tone audiometry showed conduction hearing loss of 30-40 dB across all frequencies in the left ear; high-resolution computed tomography of the temporal bone revealed that the mastoid and tympanic cavity were completely obscured. The intraoperative finding showed a caseous space-occupying mass that completely filled the tympanic cavity. The suspected diagnosis of tuberculosis was corroborated by pathohistological, microbiological and molecular biological tests. Tuberculostatic therapy was initiated at a different location. Although tuberculosis of the middle ear is a rare condition in Germany, it should nevertheless be considered when making a differential diagnosis, especially in high-risk patients where cholesteatoma is suspected on clinical and radiological evidence or in patients with a chronic middle ear process.

Impact of Elevation of Temporal Lobe During Middle Fossa Acoustic Neuroma Surgery on Contralateral Speech Discrimination.

Aim: For middle fossa acoustic neuroma approach, retractors are needed to elevate the temporal lobe to be able to access the internal auditory meatus. The temporal lobe hosts the primary and secondary auditory fields. The question arises regarding whether this elevation affects the functionality of the auditory cortex. Material and Methods: In patients, who underwent acoustic neuroma surgery, contralateral speech discrimination was tested pre- and postsurgery using different speech discrimination tests. Results of patients with a middle fossa approach were compared with patients with a translabyrinthine approach. Results: No major differences between the translabyrinthine and the middle fossa approach could be detected. Conclusion: Elevation of the temporal lobe during middle fossa approach for acoustic neuroma surgery does not lead to short-term impaired contralateral speech discrimination compared with translabyrinthine approach.

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A 58-year-old patient presented after having undergone radiation therapy, afterloading therapy and chemotherapy of a T4 nasopharynx carcinoma. On the basis of the MRI findings, local tumour recurrence was suspected. The samples taken from the nasopharynx and the left maxillary sinus confirmed this diagnosis. Neuroradiological imaging showed that the tumour extended into the area around the left skull base and also revealed an irregular formation located in the left temporal flap. Therefore not only tumour resection (Fisch approach type C) but also a temporal craniotomy was indicated in order to determine the degree of intracerebral tumour extension. The dura mater, which had been intact, was intraoperatively opened and revealed vital brain tissue, i.e. tumour infiltration had not reached the brain. It was concluded that the radiological findings probably indicated a postradiogenic necrosis of the temporal flap. The presented case illustrates the rare differential diagnostic procedure carried out in a patient with radiogenic necrosis while taking into account the possibility of local tumour infiltration into the brain parenchyma.