Langerhans cell histiocytosis involving the temporal bone with destruction and subsequent reossification of the bony labyrinth boundaries.

PURPOSE: With an incidence between 1-9/100 000 per year, Langerhans cell histiocytosis (LCH) is a rather rare disease from the hemato-oncologic disease spectrum (Hayes et al. 2009). The tumorlike disease with proliferation of histiocytic cells may manifest as localized to one organ or disseminated with infiltration of a wide variety of organs. Approximately 25-30 % of these cases show involvement of the temporal bone (Ni et al. 2017). CASE DESCRIPTION: With vertigo persisting for three years, chronic mastoiditis, and acute progressive hearing loss bilaterally (r > l) for three weeks, a 41-year-old woman presented at an emergency department. The DVT showed extensive bony destruction of large parts of the temporal bone on both sides, involving the vestibular organ, the cochlea, and the internal auditory canal. To confirm the suspicion of a systemic inflammatory process, a PE was performed from the mastoid with bioptic confirmation of an LCH. Systemic therapy was initiated. Post-therapeutic imaging showed almost complete remission with reossification of the preexisting defect zones and the internal auditory canal and labyrinth structures again showed bony margins. Clinically, there was an improvement of the vegetative symptoms with remaining bilateral sensorineural hearing loss. DISCUSSION: LCH of the temporal bone is a rare and often misdiagnosed disease due to its nonspecific clinical presentation. Awareness of temporal bone LCH and its occurrence in adults is essential for accurate and consistent diagnosis. KEY POINTS: · LCH is a rather rare disease from the hemato-oncological spectrum. · Affection of the temporal bone, especially such an extensive one (as in this case report), is rather atypical in adulthood. · Use of systemic therapy resulted in remission. · There was complete reossification of the osseous structures post-therapy. · A cochlear implant was able to be implanted to compensate for hearing loss.

Vestibular Aqueduct Size Correlates With the Degree of Cochlear Hydrops in Patients With and Without Menière's Disease.

OBJECTIVE: To correlate the CT imaging findings of the visibility and size of the vestibular aqueduct (VA) with the degree of the cochlear hydrops determined in MRI late imaging of the hydrops. Study Design: Retrospective study. Setting: Tertiary referral center. Patients: A total of 127 patients (62 women, 65 men, average age 55.6 yrs): 86 of these were diagnosed with Menière's disease (American Academy of Otolaryngology-Head and Neck Surgery [AAO-HNS] criteria; 67 unilateral, 19 bilateral). INTERVENTIONS: Temporal bone CT and hydrops MRI were performed in all patients. MAIN OUTCOME MEASURES: Visibility/width of the VA in temporal bone CT and grade of cochlear hydrops evaluated by MRI. RESULTS: The width of the VA is significantly smaller in patients diagnosed with Menière's disease (30% non-visible VA), compared with the patients who did not fulfill the diagnostic criteria of Menière's disease (12% non-visible VA) (double sided Spearman correlation, p < 0.001). In all ears of patients diagnosed with Menière's disease the width of the VA was significantly correlated with the degree of the cochlear hydrops (in cases of non-visible VA 65% [34/52] ears presented with hydrops grade 3 or 4; 13% [7/52] ears presented with hydrops grade 1 or 2 and 21% [11/52] ears showed no hydrops) (Spearman correlation p = 0.001/p < 0.01). This is also true for all ears that can be summarized as hydrophic ear disease (symptomatic ears that present with a hydrops in MRI). CONCLUSIONS: The results of our study could confirm the importance of the VA in the pathogenesis of the endolymphatic hydrops in vivo.

Does severity of cerebral MRI lesions in congenital CMV infection correlates with the outcome of cochlear implantation?

The objective is to investigate whether there is a correlation between the severity of typical brain lesions in congenital cytomegalovirus (cCMV) infection and cochlear implant (CI) outcome. The design of the study is a retrospective single-institutional chart review (2005-2015), performed in a tertiary academic referral center. 23 children with typical signs of cCMV infection on cerebral magnetic resonance imaging (MRI) and bilateral severe-to-profound sensorineural hearing loss were retrospectively evaluated. They were graded in three groups according to the severity of brain involvement. The average implantation age of the first CI is 1.8 years (range 0.6-5.8). Five patients were implanted unilaterally, 18 bilaterally. The average follow-up time after implantation was 3.3 years (range 0.6-6.9). Hearing performance was assessed using the Categories of Auditory Performance (CAP), and speech development was assessed using Speech Intelligibility Rating (SIR). The outcome in each group showed great variation. The majority of children achieved moderate-to-good auditory and speech rehabilitation. The children with severe MRI changes had comparatively better auditory than speech scores. There were children with good auditory performance (CAP ≥6) both in grades II and III, while poor performers (CAP ≤3) were encountered in each group. The severity of brain lesions on its own does not directly correlate with the outcome of cochlear implantation. Despite good retrospective diagnostic evidence of cCMV infection through MRI patterns, this has no predictive role for future hearing and speech rehabilitation.

Aplasia of the cochlea: radiologic assessment and options for hearing rehabilitation.

OBJECTIVE: Hearing rehabilitation of patients with severe inner ear malformations remains controversial. Our objective was to describe the radiologic findings of aplasia of the cochlea (AC) and evaluate the existing therapeutic options in such patients. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: Pediatric and adult patients with AC evaluated at our institution from 1995 to 2010. INTERVENTIONS: The precise radiologic findings were identified using high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) scans of the inner ear. In cases of auditory implantation on the AC side, the achieved outcome was recorded using categories of auditory performance (CAP). Related surgical aspects were analyzed. RESULTS: Twenty-three patients (28 ears) with AC were found. In 5 patients AC was bilateral. The remaining unilateral cases had contralateral normal ears (2 patients), cochlea hypoplasia (5 patients), common cavity (6 patients), incomplete partition Type I (4 patients), and atresia of the internal auditory canal (1 patient). Four patients (3 bilateral, 1 unilateral ACs) were treated with cochlear implants in ears with AC, and 1 patient underwent auditory brainstem implantation. All implanted patients achieved speech perception with limited vocabulary (CAP scores between 4 and 5). CONCLUSION: AC is defined as the total absence of the cochlea, with a present, although malformed, vestibule. Although a distinct auditory nerve was not seen in these cases of AC, results following cochlear implantation suggest functional cochlear nerve fibers in the remaining dysplastic inner ear structures. In selected cases, cochlear implantation may be a reasonable option for the habilitation of deafness associated with AC.

Controlling the position and the dislocation of the middle ear transducer with high-resolution computed tomography and digital volume tomography: implications for the transducers' design.

A minimal tip dislocation of the middle ear transducer (MET(®), Otologics Ltd) may result in poor hearing performance. Our objective was to examine if a defined MET dislocation can be diagnosed by high-resolution computed tomography (HRCT) or digital volume tomography (DVT). A human cadaver head was sequentially implanted with different MET tips (incus application) including a ceramic tip (T 1c), a titanium tip (T 1t), a new, thinner titanium tip (T 2), and a spherical titanium tip (Ts). HRCT and DVT studies were performed. Afterward, the tips were pulled back 0.5 mm, so that they were not attached to the incus. HRCT and DVT scans were repeated to identify the dislocation. Using the best plain in HRCT images, the dislocation of the transducer could be measured reliably and reproducibly in half of the cases. In particular, the precise positioning and the dislocation could be identified when T 1t and Ts were implanted, with the Ts showing the best visibility. DVT failed in recognizing the dislocation in all cases. The identification of MET tip's dislocation with HRCT depends on the shape, size, and material of the tip. This knowledge is useful for the design of the implants, as determination of the right position of the middle ear transducer may be proven important for the hearing outcome. In some cases, however, surgical exploration may still be required. Although DVT represents a promising imaging method for the otologists, it can barely help when MET dislocation is suspected.

Radiological diagnosis of incomplete partition type I versus type II: significance for cochlear implantation.

OBJECTIVES: To investigate an extended cohort of patients with incomplete partition (IP) and examine the adequacy of the existing classifications based on radiological criteria and on their implications for cochlear implantation. METHODS: Patients with IP admitted to a tertiary referral centre during the period 2000-2010 were retrospectively examined. The subjects were initially classified into IP-I, IP-II and atypical cases. For cochlear implant recipients relevant aspects were analysed. RESULTS: Eighty-three ears (49 patients) with IP were found, 19 with IP-I, 54 with IP-II and 10 atypical. Thirty-three patients received a cochlear implant (11 with IP-I, 19 with IP-II and three atypical) achieving heterogeneous though mostly promising results. Cerebrospinal fluid gushing was the commonest surgical complication, particularly in cases of IP-I. In general, patients with IP-II performed better than those with IP-I. CONCLUSIONS: Cochlear implantation promises adequate hearing rehabilitation for most patients with IP. As we move from IP-I to IP-II better results and lower risk for gushing shall be expected. Based on radiological findings we suggest a modified classification into IP-I, atypical IP-I (with large vestibular aqueduct (LVA) and better partition), IP-II (Mondini deformity) and atypical IP-IIa (without LVA) and b (without LVA but with semicircular canal dysplasia). KEY POINTS: • Radiological (CT and MR) features are of crucial importance for cochlear implantation • Imaging can identify two types of incomplete cochlear partition and atypical cases • Detailed pre-operative radiological assessment can help predict complications and outcome • A more comprehensive radiological classification of these anomalies is proposed.

Persistent petrosquamosal sinus: high incidence in cases of complete aplasia of the semicircular canals.

PURPOSE: To determine the frequency and to describe the morphologic characteristics and associated skull base anomalies of the petrosquamosal sinus (PSS) in cochlear implant candidates with complete aplasia of the semicircular canals (SCCs). MATERIALS AND METHODS: Ethics committee approval was obtained. Index cases were retrospectively selected from an electronic database in which all inner ear malformations observed in patients presenting to a tertiary referral center between 1995 and 2010 were collected. Computed tomography (CT) data were reviewed by neuroradiologists. Clinical consequences of the neuroradiologic findings were analyzed. The Pearson χ(2) test and the Mann-Whitney U test were used to determine significant differences between the number of PSSs observed in cases of complete aplasia of the SCCs and the number observed in cases of other types of inner ear malformations. RESULTS: Inner ear malformations were analyzed in 241 patients. Thirty-one patients (13%) with bilateral SCC aplasia were identified. Among 31 patients, a uni- or bilateral PSS was observed in 25 (81%). In the ears with SCC aplasia, a PSS was observed in 40 (65%) of 62. The three cases in which these PSS occupy the largest area correlate with bilateral absence of the jugular foramen. In seven of eight ears with a PSS, the PSS inhibited surgical exposure or resulted in accidental opening of the PSS during surgery. In all other patients with inner ear malformations, a PSS was observed in 39 (9%) of 412 ears only. CONCLUSION: The PSS presents a risk for cochlear implant surgery that can be detected by the neuroradiologist in advance. Venous CT angiography is advisable in certain cases. The previous assumption that a persistent PSS is encountered more frequently in cases of skull base deformity can be affirmed in the special situation of complete aplasia of the SCCs.

From labyrinthine aplasia to otocyst deformity.

INTRODUCTION: Inner ear malformations (IEMs) are rare and it is unusual to encounter the rarest of them, namely labyrinthine aplasia (LA) and otocyst deformity. They do, however, provide useful pointers as to the early embryonic development of the ear. LA is characterised as a complete absence of inner ear structures. While some common findings do emerge, a clear definition of the otocyst deformity does not exist. It is often confused with the common cavity first described by Edward Cock. Our purpose was to radiologically characterise LA and otocyst deformity. METHODS: Retrospective analysis of CT and MRI data from four patients with LA or otocyst deformity. Middle and inner ear findings were categorised by two neuroradiologists. RESULTS: The bony carotid canal was found to be absent in all patients. Posterior located cystic structures were found in association with LA and otocyst deformity. In the most severe cases, only soft tissue was present at the medial border of the middle ear cavity. The individuals with otocyst deformity also had hypoplasia of the petrous apex bone. CONCLUSIONS: These cases demonstrate gradual changes in the two most severe IEMs. Clarification of terms was necessary and, based on these findings, we propose defining otocyst deformity as a cystic structure in place of the inner ear, with the cochlea, IAC and carotid canal absent. This condition needs to be differentiated from the common cavity described by Edward Cook. A clear definition of inner ear malformations is essential if outcomes following cochlear implantation are to be compared.