The term is often used inappropriately to describe any cochlear abnormality, rather than a specific type of cochlear hypoplasia. Thus, most would favour not using the term, except perhaps in cases where the findings exactly match those described by Mondini.
Patients have sensorineural hearing loss, which is usually bilateral as the basal turn of the cochlea is intact, high-frequency hearing is generally preserved.
The abnormality is thought to result from a relatively late insult during the 7th week of embryological development when most of the inner ear has already formed. Earlier insults result in more severe abnormalities (Michel deformity, cochlear aplasia and cochlear hypoplasia).
There are only 1.5 turns to the cochlea instead of the expected 2.5. The interscalar septum between the middle and apical segments also fails to form leading to a confluent, sac-like cochlea
Mondini dysplasia has been associated with thalidomide and rubella embryopathies as well as a number of syndromes:
- Pendred syndrome: bilateral sensorineural hearing loss and goitre 3,5
- CHARGE syndrome 4
- Klippel-Feil syndrome 5
- DiGeorge syndrome 5
- Wildervanck syndrome 5
Some publications have suggested a link between Mondini malformation and spontaneous CSF fistulae and meningitis; however, this appears to be only the case with more severe forms of cochlear hypoplasia, and not with a true isolated Mondini malformation 1,4.
The Mondini abnormality consists a triad 1:
- abnormal cochlea
- only 1.5 turns (instead of the normal 2.5 turns)
- normal basal turn with a cystic apex in place of the distal 1.5 turns
- enlarged vestibule with normal semicircular canals
- enlarged vestibular aqueduct containing a dilated endolymphatic sac
Additionally, complete or partial absence of the normal interscalar septum is also present, which can now be demonstrated on high-resolution MRI 4.
Treatment and prognosis
Hearing can be improved by implantation of a multichannel cochlear implant 6.
There is an increased risk of:
History and etymology
It was first described in Latin by Carlo Mondini (1729-1803), an Italian anatomist, in 1791 1,2.
- 1. Lo WW. What is a 'Mondini' and what difference does a name make? AJNR Am J Neuroradiol. 1999;20 (8): 1442-4. AJNR Am J Neuroradiol (full text) - Pubmed citation
- 2. Carlo Mondini from whonamedit.com, the dictionary of medical eponyms. Carlo Mondini
- 3. Goldfeld M, Glaser B, Nassir E et-al. CT of the ear in Pendred syndrome. Radiology. 2005;235 (2): 537-40. doi:10.1148/radiol.2352031583 - Pubmed citation
- 4. Som PM, Curtin HD. Head and Neck Imaging, Volume 1 und. Mosby. (2003) ISBN:0323009425. Read it at Google Books - Find it at Amazon
- 5. Gorlin RJ, Toriello HV, Cohen MM. Hereditary hearing loss and its syndromes. Oxford University Press, USA. (1995) ISBN:0195065522. Read it at Google Books - Find it at Amazon
- 6. Bluestone CD, Stool SE, Alper CM et-al. Pediatric Otolaryngology, 2-Volume Set. W.B. Saunders Company. (2003) ISBN:0721691978. Read it at Google Books - Find it at Amazon
Inner ear pathology
inner ear anatomy
- enlarged vestibular aqueduct
- semicircular canal dysplasia
- classification of cochlear anomalies
- infection and inflammation
- trauma and miscellaneous