Restudy of malformations of the internal auditory meatus, cochlear nerve canal and cochlear nerve

Youjin Li, Jun Yang, Jinfen Liu, Hao Wu, Youjin Li, Jun Yang, Jinfen Liu, Hao Wu

Abstract

The present study aims to restudy the correlation between the internal auditory meatus (IAM), the cochlear nerve canal (CNC), the cochlear nerve (CN) and inner ear malformations. In this retrospective study design, the abnormal diameter of the IAM, CNC and CN in patients with any kind of inner ear malformations was evaluated using multi-slice spiral computed tomography (MSCT) (37 patients) and magnetic resonance imaging (MRI) (18 patients). Of 37 MSCT-diagnosed patients, 2 had IAM atresia, 11 IAM stenosis, 22 enlarged IAM, and 2 normal IAM with an abnormal CN. MRI diagnoses of 18 patients revealed 8 cases of aplastic CN, 6 hypoplastic CN, and 4 normal CN. CNC stenosis was associated with CN hypoplasia (P < 0.001). Patients with absent or stenotic IAM had less CN development than those with normal or enlarged IAM (P = 0.001). We propose a modification of the existing classification systems with a view to distinguishing malformations of the IAM, CNC and CN.

Figures

Fig. 1
Fig. 1
Stenosis of bilateral IAMs with an undetected CN. Male, 4 years old. Total hearing loss in the right ear, moderately severe hearing loss in the left ear. a, b, d CT shows bilateral stenosis of IAM, normal development of the cochlea (arrow). The diameters of the CNC are 0.9 and 0.6 mm. c, e Undetected CN with oblique sagittal reconstruction of MRI
Fig. 2
Fig. 2
Enlargement of bilateral IAMs with CN hypoplasia. Male, 6 years old. Bilateral severe hearing loss. a, b Enlargement of the IAM, binaural enlarged vestibular aqueducts. The CNC on the right side is 1.9 mm (a), whereas 1.8 mm on the left side (b). c, d Oblique sagittal reconstruction of MRI imaging shows normal development of the right CN, FN and vestibular nerve in the IAM (c); the diameter of the left CN is smaller than that of the FN, suggesting CN hypoplasia (d)
Fig. 3
Fig. 3
Enlargement of the IAM, with normal CN. Female, 2 years old. Bilateral severe hearing loss. a, b Axial CT shows an enlarged IAM. The CNC on the right side is 2.1 mm (a); 2.2 mm on the left side (b). c, d Oblique sagittal reconstruction of an MRI image shows normal development of the facial nerve in the IAM, the vestibular nerve, and the CN
Fig. 4
Fig. 4
Normal IAM with an aplastic CN. Female, 2 years old. The right ear has total hearing loss and the left ear has normal hearing. a Axial CT shows a normal IAM. The diameter of the CNC is 0.8 mm (arrow). b Oblique sagittal reconstruction of an MRI shows the FN and vestibular nerve in the IAM. The CN is absent

References

    1. Mehl AL, Thomson V. The Colorado newborn hearing screening project, 1992–1999: on the threshold of effective population-based universal newborn hearing screening. Pediatrics. 2002;109:E7. doi: 10.1542/peds.109.1.e7.
    1. Marazita ML, Ploughman LM, Rawlings B, Remington E, Arnos KS, Nance WE. Genetic epidemiological studies of early-onset deafness in the US school-age population. Am J Med Genet. 1993;46:486–491. doi: 10.1002/ajmg.1320460504.
    1. Scheich H, Baumgart F, Gaschler-Markefski B, et al. Functional magnetic resonance imaging of a human auditory cortex area involved in foreground-background decomposition. Eur J Neurosci. 1998;10:803–809. doi: 10.1046/j.1460-9568.1998.00086.x.
    1. Jackler RK, Luxford WM, House WF. Congenital malformations of the inner ear: a classification based on embryogenesis. Laryngoscope. 1987;97:2–14. doi: 10.1002/lary.5540971301.
    1. Sennaroglu L, Saatci I. A new classification for cochleovestibular malformations. Laryngoscope. 2002;112:2230–2241. doi: 10.1097/00005537-200212000-00019.
    1. Casselman JW, Offeciers EF, De Foer B, Govaerts P, Kuhweide R, Somers T. CT and MR imaging of congenital abnormalities of the inner ear and internal auditory canal. Eur J Radiol. 2001;40:94–104. doi: 10.1016/S0720-048X(01)00377-1.
    1. Stjernholm C, Muren C. Dimensions of the cochlear nerve canal: a radioanatomic investigation. Acta Otolaryngol (Stockh) 2002;122:43–48. doi: 10.1080/00016480252775724.
    1. Kim HS, Kim DI, Chung IH, Lee WS, Kim KY. Topographical relationship of the facial and vestibulocochlear nerves in the subarachnoid space and internal auditory canal. AJNR Am J Neuroradiol. 1998;19:1155–1161.
    1. Olivares FP, Schuknecht HF. Width of the internal auditory canal. A histological study. Ann Otol Rhinol Laryngol. 1979;88:316–323. doi: 10.1177/000348947908800303.
    1. Sakashita T, Sando I. Postnatal development of the internal auditory canal studied by computer-aided three-dimensional reconstruction and measurement. Ann Otol Rhinol Laryngol. 1995;104:469–475. doi: 10.1177/000348949510400610.
    1. Cho YS, Na DG, Jung JY, Hong SH. Narrow internal auditory canal syndrome: parasagittal reconstruction. J Laryngol Otol. 2000;114:392–394. doi: 10.1258/0022215001905661.
    1. Ozeki M, Kato Z, Sasai H, et al. Congenital inner ear malformations without sensorineural hearing loss in children. Int J Pediatr Otorhinolaryngol. 2009;73:1484–1487. doi: 10.1016/j.ijporl.2009.07.013.
    1. Swartz JD, Harnsberger HR. The otic capsule and otodystrophies. In: Swartz JD, Harnsberger HR, editors. Imaging of the temporal bone. New York: Thieme; 1998. pp. 240–266.
    1. Shelton C, Luxford WM, Tonokawa LL, Lo WW, House WF. The narrow internal auditory canal in children: a contraindication to cochlear implants. Otolaryngol Head Neck Surg. 1989;100:227–231.
    1. McClay JE, Tandy R, Grundfast K, et al. Major and minor temporal bone abnormalities in children with and without congenital sensorineural hearing loss. Arch Otolaryngol Head Neck Surg. 2002;128:664–671. doi: 10.1001/archotol.128.6.664.
    1. Bonaldi LV, do Lago A, Crema LC, Fukuda Y, Smith RL. Internal auditory canal: pre- and postnatal growth. J Otolaryngol. 2004;33:243–247. doi: 10.2310/7070.2004.02006.
    1. Fatterpekar GM, Mukherji SK, Alley J, Lin Y, Castillo M. Hypoplasia of the bony canal for the cochlear nerve in patients with congenital sensorineural hearing loss: initial observations. Radiology. 2000;215:243–246. doi: 10.1148/radiology.215.1.r00ap36243.
    1. Miyasaka M, Nosaka S, Morimoto N, Taiji H, Masaki H. CT and MR imaging for pediatric cochlear implantation: emphasis on the relationship between the cochlear nerve canal and the cochlear nerve. Pediatr Radiol. 2010;40:1509–1516. doi: 10.1007/s00247-010-1609-7.
    1. Kono T. Computed tomographic features of the bony canal of the cochlear nerve in pediatric patients with unilateral sensorineural hearing loss. Radiat Med. 2008;26:115–119. doi: 10.1007/s11604-007-0204-9.
    1. Teissier N, Van Den Abbeele T, Sebag G, Elmaleh-Berges M. Computed tomography measurements of the normal and the pathologic cochlea in children. Pediatr Radiol. 2010;40:275–283. doi: 10.1007/s00247-009-1423-2.
    1. Komatsubara S, Haruta A, Nagano Y, Kodama T. Evaluation of cochlear nerve imaging in severe congenital sensorineural hearing loss. ORL J Otorhinolaryngol Relat Spec. 2007;69:198–202. doi: 10.1159/000099231.
    1. Adunka OF, Roush PA, Teagle HF, et al. Internal auditory canal morphology in children with cochlear nerve deficiency. Otol Neurotol. 2006;27:793–801. doi: 10.1097/01.mao.0000227895.34915.94.
    1. Zhang Z, Li Y, Hu L, Wang Z, Huang Q, Wu H. Cochlear implantation in children with cochlear nerve deficiency: a report of nine cases. Int J Pediatr Otorhinolaryngol. 2012;76:1188–1195. doi: 10.1016/j.ijporl.2012.05.003.
    1. Thai-Van H, Bernard F, Isabelle B, et al. Functional magnetic resonance imaging may avoid misdiagnosis of cochleovestibular nerve aplasia in congenital deafness. Am J Otology. 2000;21:663–670.

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