New Classification of Cochlear Hypoplasia Type Malformation: Relevance in Cochlear Implantation.

OBJECTIVES: This paper attempts to create a new classification type of cochlear hypoplasia (CH)-type malformation taking into consideration of vestibular section and internal auditory canal (IAC). MATERIALS AND METHODS: Preoperative computed-tomography (CT) scans of cochlear implant (CI) candidates (N=31) from various clinics across the world with CH type malformation were taken for analysis. CT dataset were loaded into 3D-slicer freeware for three-dimensional (3D) segmentation of the inner-ear by capturing complete inner-ear structures from the entire dataset. Cochlear size in terms of diameter of available cochlear basal turn and length of cochlear lumen was measured from the dataset. In addition, structural connection between IAC and cochlear portions was scrutinized, which is highly relevant to the proposed CH classification in this study. RESULTS: CH group-I has the normal presence of IAC leading to cochlear and vestibular portions, whereas CH group-II is like CH group-I but with some degree of disruption in vestibular portion. In CH group-III, a disconnection between IAC and the cochlear portion irrespective of other features. Within all these three CH groups, the basal turn diameter varied between 3.1 mm and 9.6 mm, and the corresponding cochlear lumen length varied between 3 mm and 21 mm for the CI electrode array placement. CONCLUSION: A new classification of CH mainly based on the IAC connecting the cochlear and vestibular portions is presented in this study. CI electrode array length could be selected based on the length of the cochlear lumen, which can be observed from the 3D image.

[The use of magnetic resonance in the study of sensorineural hearing loss in children]. / Utilidad de la rm en el estudio de la hipoacusia neurosensorial unilateral infantil.

Although newborn screening of congenital hearing loss through otoacustic emissions allow prompt recognition, imaging techniques, such as CT and MRI are needed to get a morphological diagnosis. Furthermore they can be very useful in unilateral cases, whose clinical presentation is belated and more insidious. Our aim is to show the utility of MRI in the study of inner ear congenital anomalies, whose presentation is belated. Thus from a series of 88 consecutive patients in which a MRI was performed as screening of assymetric sensorineural hearing loss, we selected 6 cases aged between 6 and 20. Four of them showed an inner ear anomaly on MRI. We present these anomalies commenting the findings on CT and MRI. Imaging techniques are required to start hearing rehabilitation programs early on patients with bilateral inner ear anomalies. But also they are very useful in the evaluation of unilateral assymetric sensorineural hearing loss, in young patients, even if only some frequencies are damned, to determine the nature of hearing loss.

Cochlear ossification after meningitis.

OBJECTIVE: This study aimed to assess the pathologic processes that result in ossification of the cochlear lumen after bacterial meningitis. STUDY DESIGN: The study design was a retrospective case review. SETTING: The study was conducted at a tertiary referral center. PATIENTS: Profoundly deaf postmeningitic patients who underwent cochlear implantation were studied. INTERVENTIONS: Diagnostic and therapeutic observations were performed. MAIN OUTCOME MEASURES: The extent of cochlear ossification is classified and related to age at which infection occurred, cerebrospinal fluid leukocyte count, Gram's stain, organism, and delay between meningitis and implantation. The extent of ossification noted on high-definition computed tomographic (CT) scan is compared with surgical findings and related to the time delays between meningitis, imaging, and surgery. RESULTS: Ossification fell into three groups: gross ossification of the scala tympani and variable amounts of the scala vestibuli; partial ossification localized to the basal turn of the scala tympani; and no ossification. There was no correlation between the extent of ossification and the age when infected, type of pathogen, cerebrospinal fluid leukocyte count, and time delay between meningitis and implantation. Visualization of bacteria on Gram's stain was a highly sensitive measure of ossification (0.93) but was not specific (0.6) with positive and negative predictive values of 0.76 and 0.86, respectively. High-definition CT underestimated the extent of ossification in 50% of cases when performed within 6 months of meningitis. CONCLUSIONS: Ossification is either gross or localized to the basal turn of the scala tympani. If ossification does occur, it is rapid and complete within a few months of infection. The visualization of bacteria on Gram's stain is a sensitive indicator for the presence of ossification but has low specificity. High-definition CT, if performed within the first 6 months of meningitis, can be an inaccurate diagnostic tool and therefore should be performed as close to the date of surgery as possible.

Effectiveness of hyperbaric oxygen therapy in patients with acute and chronic cochlear disorders.

Over the course of 18 months 359 patients with defined acute and chronic inner ear disorders who had not responded to treatment with medication were given hyperbaric oxygen (HBO) therapy. The inner ear diseases of the patients were divided, based on the duration of their conditions, into four symptomatic groups. Of the patients who had had hearing loss for less than 3 months, noticeable improvement or complete recovery was seen in 13% (20 dB in at least three test frequencies); 25.2% showed an improvement between 10 and 20 dB. Changes up to 10 dB or less were not considered to be positive. Patients with a pretreated hearing loss for more than 3 months had markedly less benefit from HBO therapy. Two percent regained normal hearing function. In 30% an improvement of more than 10 dB was achieved. For patients who had suffered from tinnitus for less than 3 months excellent improvement was seen in 6.7% and noticeable improvement in 44.3% expressed by means of a visual analog scale. In 44.3% the tinnitus was described as unchanged. Patients who had had tinnitus for more than 3 months before HBO therapy showed a less favorable response to HBO. In none of the patients did the tinnitus disappear; 34.4% of the patients described a noticeable improvement in their complaints.