PhiliPPine Journal of otolaryngology-head and neck Surgery  41

PhiliPPine Journal of otolaryngology-head and neck Surgery                                                       Vol. 25  no. 1  January – June 2010

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A 5-year-old female with bilateral profound hearing loss underwent computerized 
tomographic imaging of the temporal bone as part of the work-up to determine the etiology 
of her deafness and to delineate middle and inner ear anatomy prior to cochlear implantation. 
The examination revealed an inner ear malformation which based on the newest classification 
of cochleovestibular malformations by Sennaroglu and Saatci, is called an incomplete partition 
type I (IP-1) or cystic cochleovestibular malformation. This condition is characterized by: (1) a 
cochlea that is lacking the entire modiolus and cribriform area resulting in a cystic appearance; 
and (2) a large cystic vestibule.1

Cystic Cochleovestibular Malformation 
(Incomplete Partition Type 1)

Nathaniel W. Yang, MD

Department of Otorhinolaryngology
College of Medicine – Philippine General Hospital
University of the Philippines Manila

Philippine National Ear Institute
National Institutes of Health
University of the Philippines Manila

Department of Otorhinolaryngology
Head and Neck Surgery
Far Eastern University–Nicanor Reyes Memorial
Foundation Medical Center

Correspondence: Nathaniel W. Yang, MD
Department of Otorhinolaryngology
Ward 10, Philippine General Hospital
Taft Avenue, Ermita, Manila 1000
Philippines
Phone: (632) 526 4360
Fax: (632) 525 5444
Email: nwyang@gmx.net
Reprints will not be available from the author. Philipp J Otolaryngol Head Neck Surg 2010; 25 (1): 41-42 c  Philippine Society of Otolaryngology – Head and Neck Surgery, Inc.

Figure 1. Axial view of the abnormal inner ear showing the cystic cochlea (+) and the cystic vestibule (*) 
without the central bony island usually found in the horizontal semicircular canal.



                                PhiliPPine Journal of otolaryngology-head and neck Surgery                                                          Vol. 25  no. 1  January – June 2010   

42  PhiliPPine Journal of otolaryngology-head and neck Surgery

FROM THE VIEWBOX

REFERENCES 
1. Sennaroglu L, Saatci I. A new classification for cochleovestibular malformations. Laryngoscope 

2002; 112: 2230-2241.
2. Preciado DA, Lawson L, Maden C, et al. Improved diagnostic effectiveness with a sequential 

diagnostic paradigm in idiopathic pediatric sensorineural hearing loss. Otology & Neurotology 
2005; 26: 610-615.

3. Park AH, Kou B, Hotaling A, et al. Clinical course of pediatric congenital inner ear malformations. 
Laryngoscope 2000; 110: 1715-1719.

Figure 2. Axial view of a normal inner ear at the same level as Figure 1,  showing the “signet ring” 
configuration of the horizontal semicircular canal and vestibule (*) and the first turn of the cochlea (+).

Temporal bone imaging is among the most useful examinations in the 
etiological investigation of idiopathic sensorineural hearing loss in children, with up 
to 30%2 of the imaging studies showing an abnormality. The detection of inner ear 
malformations is important as some abnormalities are associated with an increased 
risk of meningitis or progressive hearing loss following head trauma.3 Likewise, the 
approach to cochlear implantation may be influenced by the type of malformation. 
In this particular patient, the use of a cochlear implant with a full-band electrode 
design may be more appropriate, as the location of the neural elements within the 
cystic cochlea is not definitely known.