The vestibulocochlear nerve: aplasia and hypoplasia in combination with inner ear malformations

Giesemann, Anja; Kontorinis, Georgios; Zajaczek, J. E. W.; Lenarz, Thomas; Lanfermann, Heinrich; Goetz, Friedrich

doi:10.1007/s00330-011-2287-z

Cited by 37 publications

(20 citation statements)

References 13 publications

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“…In accordance with Giesemann et al [29] the present study found that IP-I malformations can be associated with hypoplastic/aplastic cochlear nerves. Hence, the diameter of the cochlear nerve was normal in all patients with IP-II and IP-III malformations in this study.…”

Section: Discussionsupporting

confidence: 93%

Audiological and Radiological Characteristics in Incomplete Partition Malformations

Batuk¹,

Çınar²,

Özgen³

et al. 2017

Int Adv Otol

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OBJECTIVE:To compare the audiological and radiological findings of patients with incomplete partition malformations (IPs) and analyze the relationship between the audiological and radiological findings. MATERIALS and METHODS:The study included 84 patients (168 ears) with IPs as follows: 26 patients with Type I;IP-I (41 ears), 54 patients with Type II;IP-II (108 ears), and 4 patients with Type III;IP-III (8 ears). Remaining 11 ears were diagnosed with other inner ear malformations. Air and bone conduction thresholds were determined with pure tone audiometry, and the air bone gap was recorded in all patients with IPs. Magnetic resonance imaging studies and computerized tomography scans of the temporal bones were analyzed using the PACS system of our university. RESULTS:It was found that all the ears with IP-I were diagnosed with severe to profound hearing loss. The degree of the hearing loss varied from mild to severe/profound in patients with IP-II. Severe to profound mixed hearing loss (MHL) was determined in all ears with IP-III. The air bone gap was larger in the lower frequencies in the IP-II cases diagnosed with MHL. There was not a significant difference between the air bone gap and the size of the vestibular aqueduct in ears with IP-II (p>0.05).CONCLUSION: Each type of IP has different audiological findings. Depending on the type and degree of the hearing loss, it is possible to choose the appropriate audiological intervention. Patients with IP should be evaluated according to the type of malformation.

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Section: Discussionsupporting

confidence: 93%

Audiological and Radiological Characteristics in Incomplete Partition Malformations

Batuk¹,

Çınar²,

Özgen³

et al. 2017

Int Adv Otol

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“…Although it is best to perform both CT and MRI for cochlear implant candidates, in special situations in which there are financial constraints, CT should be performed and MRI done selectively in cases where cochlear nerve deficiency is suspected. Previous studies [Casselman et al, 1997;Giesemann et al, 2012] and this study show that CVM may be accompanied by cochlear nerve deficiency, suggesting that MRI should be done to assess cochlear nerve deficiency in candidates for cochlear implantation who have CVM. We found a high incidence of cochlear nerve deficiency in children with CVM type C or type D, so our data suggest that MRI should be considered essential for patients who have CVM type C or type D on TBCT.…”

Section: Discussionmentioning

confidence: 99%

“…MRI is the choice of imaging modality to identify the status of the cochlear nerve [Casselman et al, 1997;Glastonbury et al, 2002], but MRI cannot depict the detailed mastoid anatomy as well as CT can, because of the limitation of its resolution. Furthermore, the incidence of cochlear nerve deficiency is very low in children with normal inner ear morphology [Miyasaka et al, 2010;Giesemann et al, 2012] so it is not cost-effective to undertake MRI for all cochlear implant candidates. Although it is best to perform both CT and MRI for cochlear implant candidates, in special situations in which there are financial constraints, CT should be performed and MRI done selectively in cases where cochlear nerve deficiency is suspected.…”

Section: Discussionmentioning

confidence: 99%

“…With the improved resolution of TBCT, objective measurement of cochlear dimensions can complement visual analysis and improve the detection of subtle cochlear malformations [Chen et al, 2008]. The identification of CVM before cochlear implantation is very important because it is associated with a malformed cochlear structure, abnormal distribution of spiral ganglion neurons [Graham et al, 2000], and cochlear nerve deficiency [Giesemann et al, 2012], which can result in less favorable postimplantation speech perception ability and increased surgical risk including intraoperative cerebrospinal fluid gusher [Miyamoto et al, 2002;Adunka et al, 2012] and persistent cerebrospinal fluid leakage [Page and Eby, 1997], electrode misinsertion into the IAC [Tucci et al, 1995] or facial nerve injury [Molter et al, 1993;Hoffman et al, 1997].…”

Section: Introductionmentioning

confidence: 99%

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A New Classification of Cochleovestibular Malformations and Implications for Predicting Speech Perception Ability after Cochlear Implantation

Jeong

Kim²

2015

Audiol Neurotol

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Objectives: The aims of this study were to introduce a new classification of cochleovestibular malformation (CVM) and to investigate how well this classification can predict speech perception ability after cochlear implantation in children with CVM. Methods: Fifty-nine children with CVM who had used a cochlear implant for more than 3 years were included. CVM was classified into 4 subtypes based on the morphology of the cochlea and the modiolus on temporal bone computed tomography (TBCT): normal cochlea and normal modiolus (type A, n = 16), malformed cochlea and partial modiolus (type B, n = 31), malformed cochlea and no modiolus (type C, n = 6), and no cochlea and no modiolus (type D, n = 6). Speech perception test scores were compared between the subtypes of CVM using analysis of covariance with post hoc Bonferroni test. Univariate and multivariate regression analyses were used to identify the significant predictors of the speech perception test scores. Results: The speech perception test scores after implantation were significantly better in children with CVM type A or type B than in children with CVM type C or type D. The test scores did not differ significantly between the implanted children with CVM type A or type B and those without CVM. In univariate regression analysis, the type of CVM was a significant predictor of the speech perception test scores in implanted children with CVM. Multivariate regression analysis revealed that the age at cochlear implantation, cochlear nerve size and preimplantation speech perception test scores were significant predictors of the postimplantation speech perception test scores. The chance of cochlear nerve deficiency increased progressively from CVM type A to type D. Conclusion: The new classification of CVM based on the morphology of the cochlea and the modiolus is simple and easy to use, and correlated well with postimplantation speech perception ability and cochlear nerve status. This simple classification of CVM using TBCT with cochlear nerve assessment by magnetic resonance imaging is helpful in the preoperative evaluation of children with CVM.

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“…Hypoplasia and aplasia of the vestibulocochlear nerve (VCN) is most often found in combination with certain inner ear malformations, but can also occur separately with a morphologically intact inner ear as viewed on CT scans [8]. In 1997, Casselman et al [2] classified VCN aplasia and hypoplasia as follows: type 1 as an aplasia of the VCN associated with stenosis of the internal auditory canal; type 2a as an existing common VCN with aplasia or hypoplasia of its cochlear branch and with labyrinthine malformation present; and type 2b in combination with a normal labyrinth.…”

Section: Hypoplasia and Aplasia Of The Vestibulocochlear Nerve (Vcn)mentioning

confidence: 99%

Some Remarks on Imaging of the Inner Ear: Options and Limitations

Giesemann

Hofmann

2015

Clin Neuroradiol

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The temporal bone has a highly complex anatomical structure, in which the sensory organs of the cochlea and the vestibular system are contained within a small space together with the sound-conducting system of the middle ear. Detailed imaging is thus required in this anatomical area. There are a great many clinical aims for which the highest-possible spatial resolution is required. These include the localization of cerebrospinal fluid fistulas, the detection of malformations of the middle and inner ear and the vestibulocochlear nerve, an aberrant course of the facial nerve and anomalies of the arterial and venous structures, the confirmation of dehiscence of the semicircular canals and finally, the verification of endolymphatic hydrops in cases of Ménière's disease. However, the term 'high resolution' is very time dependent. Two milestones in this respect have been (in 1991) the 3D visualization of the inner ear by means of maximum-intensity projection (MIP) of a T2-weighted constructive interference in steady state (CISS) sequence of a 1.5-tesla magnetic resonance imaging (MRI) scanner (Tanioka et al., Radiology 178:141-144, 1991) and (in 1997) imaging of the vestibulocochlear nerve for the diagnosis of hypoplasia inside the internal auditory canal using the same sequence (Casselman et al., Radiology 202:773-781, 1997).The objective of this article is to highlight the options for, and the challenges of, contemporary imaging with regard to some clinical issues relating to the inner ear.

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The vestibulocochlear nerve: aplasia and hypoplasia in combination with inner ear malformations

Cited by 37 publications

References 13 publications

Audiological and Radiological Characteristics in Incomplete Partition Malformations

Audiological and Radiological Characteristics in Incomplete Partition Malformations

A New Classification of Cochleovestibular Malformations and Implications for Predicting Speech Perception Ability after Cochlear Implantation

Some Remarks on Imaging of the Inner Ear: Options and Limitations

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