Management of transmodiolar and transmacular cochleovestibular schwannomas with and without cochlear implantation.

INTRODUCTION: Hearing rehabilitation with cochlear implants has attracted increasing interest also for patients with cochleovestibular schwannoma. The authors report their experience with the surgical management of tumors with rare transmodiolar or transmacular extension and outcomes after cochlear implantation (CI). METHODS: This retrospective case series included nine patients with either primary intralabyrinthine tumors or secondary invasion of the inner ear from the internal auditory canal. The primary endpoint with CI, performed in six patients, was word recognition score at 65 dB SPL (sound pressure level). Secondary endpoints were intra- and postoperative electrophysiological parameters, impedance measures, the presence of a wave V in the electrically evoked (via the CI) auditory brainstem responses, the specifics of postoperative CI programming, and adverse events. RESULTS: Hearing rehabilitation with CI in cases of transmodiolar tumor growth could be achieved only with incomplete tumor removal, whereas tumors with transmacular growth could be completely removed. All six patients with CI had good word recognition scores for numbers in quiet conditions (80-100% at 65 dB SPL, not later than 6 to 12 months post CI activation). Four of these six patients achieved good to very good results for monosyllabic words within 1-36 months (65-85% at 65 dB SPL). The two other patients, however, had low scores for monosyllables at 6 months (25 and 15% at 65 dB SPL, respectively) with worsening of results thereafter. CONCLUSIONS: Cochleovestibular schwannomas with transmodiolar and transmacular extension represent a rare entity with specific management requirements. Hearing rehabilitation with CI is a principal option in these patients.

[Management of transmodiolar and transmacular cochleovestibular schwannomas with and without cochlear implantation. German version]. / Management transmodiolärer und transmakulärer Vestibularis- und Cochlearisschwannome mit und ohne Cochleaimplantation.

INTRODUCTION: Hearing rehabilitation with cochlear implants has attracted increasing interest also for patients with cochleovestibular schwannoma. The authors report their experience with the surgical management of tumors with rare transmodiolar or transmacular extension and outcomes after cochlear implantation (CI). METHODS: This retrospective case series included nine patients with either primary intralabyrinthine tumors or secondary invasion of the inner ear from the internal auditory canal. The primary endpoint with CI, performed in six patients, was word recognition score at 65 dB SPL (sound pressure level). Secondary endpoints were intra- and postoperative electrophysiological parameters, impedance measures, the presence of a wave V in the electrically evoked (via the CI) auditory brainstem responses, the specifics of postoperative CI programming, and adverse events. RESULTS: Hearing rehabilitation with CI in cases of transmodiolar tumor growth could be achieved only with incomplete tumor removal, whereas tumors with transmacular growth could be completely removed. All six patients with CI had good word recognition scores for numbers in quiet conditions (80-100% at 65 dB SPL, not later than 6 to 12 months post CI activation). Four of these six patients achieved good to very good results for monosyllabic words within 1-36 months (65-85% at 65 dB SPL). The two other patients, however, had low scores for monosyllables at 6 months (25 and 15% at 65 dB SPL, respectively) with worsening of results thereafter. CONCLUSIONS: Cochleovestibular schwannomas with transmodiolar and transmacular extension represent a rare entity with specific management requirements. Hearing rehabilitation with CI is a principal option in these patients.

[The infracochlear approach for diagnostic petrous apicotomy]. / Der infracochleäre Zugang zur Felsenbeinspitze aus diagnostischer Indikation.

Diagnostic and therapeutic approaches to the petrous apex involve sub-/transtemporal, retrosigmoidal, infratemporal and-lesser invasive-e. g. infracochlear, infralabyrinthine or under favourable anatomic conditions, transsphenoidal surgical pathways. For diagnostic purposes, minimally invasive approaches should be preferred due to their lesser morbidity. This article illustrates the infracochlear approach to the petrous apex in the case of a diagnostic indication in a patient with an incidental, asymptomatic tumorous lesion of the right petrous apex with bony erosion. After the bone of the floor of the ear canal and the hypotympanum was removed, the carotid artery and the jugular bulb were identified using a diamond burr. The route to the petrous apex is triangled by the cochlea superiorly, the jugular bulb posteriorly, and the carotid artery anteriorly. After opening the petrous apex lesion, biopsies were taken. The defect in the floor of the ear canal and the hypotympanum was reconstructed with cartilage and temporalis fascia. The patient recovered quickly from surgery without vertigo or hearing loss. Histological evaluation showed a chondrosarcoma. The patient opted for primary radiation therapy (C12, 63 Gy). The infracochlear approach is minimally invasive and can offer access to the petrous apex with minimal morbidity. The pathway, however, is narrow and deep and bounded by the jugular bulb and the carotid artery. The available space can be estimated from preoperative CT scans and, if possible, with 3D reconstructions. Navigation can additionally enhance safety.

Intralabyrinthine schwannomas : Surgical management and hearing rehabilitation with cochlear implants.

Intralabyrinthine schwannomas (ILS) are a rare differential diagnosis of sudden hearing loss and vertigo. In an own case series of 12 patients, 6 tumors showed an intracochlear, 3 an intravestibular, 1 a transmodiolar including the cerebellopontine angle (CPA), 1a transotic including the CPA, and 1 a multilocular location. The tumors were removed surgically in 9 patients, whereas 3 patients decided for a "wait-and-test-and-scan" strategy. Of the surgical patients, 3 underwent labyrinthectomy and cochlear implant (CI) surgery in a single-stage procedure; 1 patient had extended cochleostomy with CI surgery; 3 underwent partial or subtotal cochleoectomy, with partial cochlear reconstruction and CI surgery (n = 1) or implantation of electrode dummies for possible later CI after repeated MRI follow-up (n = 2); and in 2 patients, the tumors of the internal auditory canal and cerebellopontine angle exhibiting transmodiolar or transmacular growth were removed by combined translabyrinthine-transotic resection. For the intracochlear tumors, vestibular function could mostly be preserved after surgery. In all cases with CI surgery, hearing rehabilitation was successful, although speech discrimination was limited for the case with subtotal cochleoectomy. Surgical removal of intracochlear schwannomas via partial or subtotal cochleoectomy is, in principle, possible with preservation of vestibular function. In the authors' opinion, radiotherapy of ILS is only indicated in isolated cases. Cochlear implantation during or after tumor resection (i. e., as synchronous or staged surgeries) is an option for hearing rehabilitation in cartain cases and represents a therapeutic approach in contrast to a "wait-and-test-and-scan" strategy.

Intracochlear schwannoma : Tumor removal via subtotal cochleoectomy and partial cochlear reconstruction with preservation of semicircular canal function.

We report about a patient, who in 2005, as a 37-year-old, experienced a sudden, mild to moderate, mid-frequency sensorineural hearing loss in the right ear, along with tinnitus and mild dizziness. MRI of the temporal bone revealed a very small (1 mm) enhancing lesion in the second turn of the right cochlea after injection of contrast medium. Hearing gradually deteriorated, with complete hearing loss in 2015. At this time, an MRI scan showed a lesion completely filling the cochlea.The tumor was removed through a subtotal cochleoectomy. The cochlea was partially reconstructed with cartilage and fascia. A cochlea implant dummy electrode was inserted as a placeholder in order to try to preserve a channel within the most likely fibrosing "neocochlea" during follow-up MRI examinations.Vestibular function tests 2 months postoperatively showed preserved caloric excitability and a normal vestibulo-ocular reflex (video head impulse test, vHIT) in all three planes. The patient is free of vertigo.Intralabyrinthine schwannomas (ILS) are a rare differential diagnosis of sudden hearing loss. Surgical removal of an intracochlear ILS through partial or subtotal cochleoectomy with preservation of vestibular function is possible.

[Intracochlear schwannoma : Tumor removal via subtotal cochleoectomy and partial cochlear reconstruction with preservation of semicircular canal function. German version]. / Intracochleäres Schwannom : Tumorentfernung über subtotale Cochleoektomie und partielle Rekonstruktion der cochleären Kapsel unter Erhalt der Bogengangsfunktion.

We report about a patient who in 2005, aged 37 years, experienced sudden mild to moderate, mid-frequency sensorineural hearing loss in the right ear along with tinnitus and mild dizziness. MRI of the temporal bone revealed a very small (1 mm) contrast-enhancing lesion in the second turn of the right cochlea. Hearing gradually deteriorated with complete hearing loss in 2015. At this time, an MRI scan showed a lesion completely filling the cochlea.The tumor was removed via transmeatal subtotal cochleoectomy. The cochlea was partially reconstructed with cartilage and fascia. A cochlea implant dummy electrode was inserted as a placeholder in order to prevent complete fibrosis of the "neocochlea" during follow-up MRI examinations.Vestibular function tests 2 months postoperatively showed preserved caloric excitability and a normal vestibulo-ocular reflex (vHIT) in all three planes. The patient is free of vertigo.Intralabyrinthine schwannomas (ILS) are a rare differential diagnosis of sudden hearing loss, which should be specifically checked for in MRI. Surgical removal of an intracochlear ILS through partial or subtotal cochleoectomy with preservation of vestibular function is possible in principle.

[Intralabyrinthine schwannomas : Surgical management and hearing rehabilitation with cochlear implants. German version]. / Intralabyrinthäre Schwannome : Chirurgisches Management und Hörrehabilitation mit Cochleaimplantaten.

Intralabyrinthine schwannomas (ILS) are a rare differential diagnosis of sudden hearing loss and vertigo. In an own case series of 12 patients, 6 tumors showed an intracochlear, 3 an intravestibular, 1 a transmodiolar including the cerebello-pontine angle (CPA), 1 a transotic including the CPA and 1 a multilocular location. The tumors were removed surgically in 9 patients, whereas 3 patients opted for a "wait-and-test-and-scan" strategy. Of the surgical patients, 3 underwent labyrinthectomy and cochlear implant (CI) surgery in a single stage procedure; 1 patient received extended cochleostomy with CI surgery; 3 underwent partial or subtotal cochleoectomy, with partial cochlear reconstruction and CI surgery (n = 1) or implantation of electrode dummies for possible later CI following repeated MRI follow-up (n = 2); and in 2 patients, the tumors of the internal auditory canal and cerebellopontile angle exhibiting transmodiolar or transmacular growth were removed by combined translabyrinthine-transotic resection. For the intracochlear tumors, vestibular function could mostly be preserved after surgery. In all cases with CI surgery, hearing rehabilitation was successful, although speech discrimination was limited for the case with subtotal cochleoectomy. Surgical removal of intracochlear schwannomas via partial or subtotal cochleoectomy is, in principle, possible with preservation of vestibular function. In the authors' opinion, radiotherapy of ILS is only indicated in isolated cases. Provided performed early enough, cochlear implantation after surgical removal of ILS is an option for auditory rehabilitation, thus representing-in contrast to the "wait-and-test-and-scan" strategy-a therapeutic approach.

[Modern imaging of the temporal bone]. / Moderne Schläfenbeinbildgebung.

This article describes the current significance of computed tomography (CT), magnetic resonance imaging (MRI), cone beam CT, digital subtraction angiography (DSA), and special X­rays in the diagnostics of temporal bone diseases. The latter is obsolete for diagnostic intentions. Possibilities and limitations in terms of detection and/or depiction of the extent of inflammatory, traumatic, tumorous, and postoperative pathologies are discussed. A concrete question and conveyance of clinical findings influence the choice of the method to be applied in the individual case. Malformations of the middle ear can only be detected noninvasively by CT or cone beam CT. These are also the methods that may support the diagnosis of otosclerosis in clinically unclear cases. MRI is the method of choice for pathologies of the inner ear and internal auditory canal, including inner ear malformations. At present, only in few institutions is a successful visualization of endolymphatic hydrops in Menière's disease realized.

Visualisation of passive middle ear implants by cone beam and multi-detector computed tomography: a comparative in vitro study.

OBJECTIVES: Modern passive middle ear titanium prostheses are filigree structures, resulting in poorer depiction on CT compared to prostheses used in the past. We compared the visibility of newer prostheses on cone beam CT (CBCT) to multi-detector CT (MDCT) with standard and lower dose in vitro, and analysed image noise and metal artefacts. METHODS: Six different titanium middle ear prostheses (three partial and one total ossicular replacement prostheses, two stapes prostheses) were implanted twice in formalin-fixed head specimens-first correctly and then with displacement. Imaging was performed using standard CBCT and MDCT as well as MDCT with lower dose (36 single imaging investigations). Images were analysed with knowledge of the used types of middle ear prostheses, but blinded with respect to the positioning in the specific case. RESULTS: On all images the type of prostheses and their positions could be clearly recognized. Their identifiability including their details was rated as statistically significantly higher for all CBCT investigations than for MDCT. MDCT with lower dose showed the worst results. No statistical differences were found in image noise and metal artefacts. CONCLUSIONS: If available, CBCT should be preferred over MDCT in diagnostic evaluation of passive middle ear prostheses. KEY POINTS: • Middle ear prostheses became more filigree, leading to poorer visibility on CT. • High spatial resolution and paraxial reconstructions are necessary requirements for imaging evaluation. • CBCT and MDCT can identify type and positioning of titanium prostheses. • Metal artefacts play a minor part in filigree titanium prostheses. • Regarding visualisation of prostheses details, cone beam CT aids the evaluation.

[Visualization of subtle temporal bone structures. Comparison of cone beam CT and MDCT]. / Darstellung subtiler Schläfenbeinstrukturen. In-vivo-Vergleich digitale Volumentomographie vs. Multidetektor-CT.

PURPOSE: The purpose of this study was to compare the visualization of subtle, non-pathological temporal bone structures on cone beam computed tomography (CBCT) and multi-detector computed tomography (MDCT) in vivo. MATERIALS AND METHODS: Temporal bone studies of images from 38 patients archived in the picture archiving and communication system (PACS) were analyzed (slice thickness MDCT 0.6 mm and CBCT 0.125 mm) of which 23 were imaged by MDCT and 15 by CBCT using optimized standard protocols. Inclusion criteria were normal radiological findings, absence of previous surgery and anatomical variants. Images were evaluated blind by three trained observers. Using a five-point scale the visualization of ten subtle structures of the temporal bone was analyzed. RESULTS: Subtle middle ear structures showed a tendency to be more easily distinguishable by CBCT with significantly better visualization of the tendon of the stapedius muscle and the crura of the stapes on CBCT (p = 0.003 and p = 0.033, respectively). In contrast, inner ear components, such as the osseus spiral lamina and the modiolus tended to be better detectable on MDCT, showing significant differences for the osseous spiral lamina (p = 0.001). The interrater reliability was 0.73 (Cohen's kappa coefficient) and intraobserver reliability was 0.89. CONCLUSION: The use of CBCT and MDCT allows equivalent and excellent imaging results if optimized protocols are chosen. With both imaging techniques subtle temporal bone structures could be visualized with a similar degree of definition. In vivo differences do not seem to be as large as suggested in several previous studies.

[Comparison of quality on digital X-ray devices with 3D-capability for ENT-clinical objectives in imaging of temporal bone and paranasal sinuses]. / Qualitätsvergleich digitaler 3D-fähiger Röntgenanlagen bei HNO-Fragestellungen am Schläfenbein und den Nasennebenhöhlen.

PURPOSE: Comparison of dosage and spatial resolution of digital X-Ray devices with 3D-capability in head and neck imaging. MATERIALS AND METHODS: Three on-site X-Ray devices, a general purpose multi-slice CT (CT), a dedicated cone-beam CT (CBCT) and the CT-mode of a device for digital angiography (DSA) of the same generation were compared using paranasal sinus (PNS) and temporal bone imaging protocols. The radiation exposure was measured with a puncture measuring chamber on a CTDI head phantom as well as with chip-strate-dosimeters on an Alderson head phantom in the regions of the eyes and thyroid gland. By using the Alderson head phantom, the specific dosage of the X-Ray device with regard to different protocols was read out. For the assessment of the high-contrast resolution of the devices, images of a self-made phantom were qualitatively analysed by six observers. RESULTS: The three devices showed marked variations in the dosage and spatial resolution depending on the protocol and/or modus. In both parameters, CBCT was superior to CT and DSA using standard protocols, with the difference being less obvious for the investigation with PNS. CONCLUSION: For high-contrast investigations CBCT CT is a remarkable option in head and neck radiology.