Classification and Current Management of Inner Ear Malformations
| I-INNER EAR MALFORMATIONS | SUBTYPE |
| 1- Complete Labyrinthine Aplasia (Michel Deformity) | a- CLA with hypoplastic or aplastic petrous bone b- CLA without otic capsule c- CLA with otic capsule |
| 2- Rudimentary Otocyst | Incomplete milimetric representations of the otic capsule (round or ovoid in shape) without an IAC, an anomaly between a Michel deformity and common cavity (CC) |
| 3- Cochlear Aplasia | a- Cochlear aplasia with normal labyrinth b- Cochlear aplasia with a dilated vestibule (CADV) |
| 4- Common Cavity | A single, ovoid or round chamber, representing cochlea and vestibule, IAC usually enters the cavity at its center |
| 5- Cochlear Hypoplasia | a- CH-I (Bud-like cochlea) b- CH-II (Cystic hypoplastic cochlea) c- CH-III (Cochlea with less than 2 turns) d- CH-IV (Cochlea with hypoplastic middle and apical turns) |
| 6- Incomplete Partition of the Cochlea | a- Incomplete partition type I (IP-I) b-Incomplete partition type II (IP-II) c- Incomplete partition type III (IP-III) |
| 7- Enlarged Vestibular Aqueduct (EVA) | The midpoint between posterior labyrinth and operculum is larger than 1.5 mm on axial sections. |
| 8- Cochlear Aperture Abnormalities | Bony cochlear nerve canal<1.4mm |
| II- COCHLEAR NERVE ABNORMALITIES | SUBTYPE |
| 1- Normal cochlear nerve (CN) | CN located in the anterior inferior part of the IAC, entering the cochlea in parasaggital sections |
| 2- Hypoplastic CN | Present separate CN but the size is less than the contralateral normal CN or ipsilateral normal facial nerve |
| 3- Absent CN | No nerve in the anteroinferior part of the IAC |
| 4- Normal CVN | Normally cochlear and vestibular nerves originate at the brainstem together forming the CVN |
| 5- Hypoplastic CVN | CVN is smaller than contralateral CVN or ipsilateral FN |
| 6- Absent CVN | CVN is absent , Only facial nerve can be identified |
Sennaroğlu L, Bajin MD. Classification and current management of inner ear malformations. Balkan Med J. 2017;34(5):397-411. doi:10.4274/balkanmedj.2017.0367