How to predict cochlear length before cochlear implantation surgery

Abstract Conclusions: The basal turn diameter of the human cochlea predicts the outer wall length of the basal and two first turns relatively well but there was less correlation for the total cochlear length. The linear regression graph defines the length of the basal turn within an error of ± 1 mm and could be used clinically to distinguish small and large cochleae. Objective: The human cochlea varies in size. The preoperative assessment of cochlear length can be crucial for non-traumatic electrode insertion and hearing preservation. In this study, we estimated the external cochlear wall length by assessing the basal turn diameter. Methods: A total of 51 non-selected, human inner ear moulds were analysed. A line was drawn from the midpoint of the round window through the cochlear mid-portion to the opposite side (A) and correlated to the cochlear turn lengths. Linear regression analyses were carried out. Results: Mean diameter A was 9.3 mm. The mean basal turn length was 22.8 mm, the two first turns were 35.1 mm and the total length was 41.2 mm. Linear regression analyses indicated a coefficient of determination (R2) of 0.74 for diameter A and the basal turn length, R2 = 0.70 for the two-turn length and R² = 0.39 for the total length.

[1]  Marco Pelizzone,et al.  Acoustic to Electric Pitch Comparisons in Cochlear Implant Subjects with Residual Hearing , 2006, Journal of the Association for Research in Otolaryngology.

[2]  Patricia A. Leake,et al.  Frequency Map for the Human Cochlear Spiral Ganglion: Implications for Cochlear Implants , 2007, Journal for the Association for Research in Otolaryngology.

[3]  Mary Hardy,et al.  The length of the organ of Corti in man , 1938 .

[4]  A. Wright,et al.  Hair cell distributions in the normal human cochlea. , 1987, Acta oto-laryngologica. Supplementum.

[5]  John K. Niparko,et al.  Cochlear Coiling Pattern and Orientation Differences in Cochlear Implant Candidates , 2011, Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology.

[6]  D. D. Greenwood.  Critical Bandwidth and the Frequency Coordinates of the Basilar Membrane , 1961 .

[7]  Graeme M. Clark,et al.  Computer-Aided Three-Dimensional Reconstruction in Human Cochlear Maps: Measurement of the Lengths of Organ of Corti, Outer Wall, Inner Wall, and Rosenthal's Canal , 1996, The Annals of otology, rhinology, and laryngology.

[8]  Johan H. M. Frijns,et al.  Cochlear Coordinates in Regard to Cochlear Implantation: A Clinically Individually Applicable 3 Dimensional CT-Based Method , 2010, Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology.

[9]  Johan H. M. Frijns,et al.  Consensus Panel on a Cochlear Coordinate System Applicable in Histologic, Physiologic, and Radiologic Studies of the Human Cochlea , 2010, Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology.

[10]  G M Clark,et al.  Improved and simplified methods for specifying positions of the electrode bands of a cochlear implant array. , 1996, The American journal of otology.

[11]  D. D. Greenwood.  A cochlear frequency-position function for several species--29 years later. , 1990, The Journal of the Acoustical Society of America.

[12]  Helge Rask-Andersen,et al.  Variational Anatomy of the Human Cochlea: Implications for Cochlear Implantation , 2009, Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology.

[13]  K. Wadin.  Radioanatomy of the high jugular fossa and the labyrinthine portion of the facial canal. A radioanatomic and clinical investigation. , 1988, Acta radiologica. Supplementum.

[14]  J. C. Farmer.  Diving Injuries to the Inner Ear , 1977, Lancet.

[15]  J. Stahle,et al.  Human Cochlear Aqueduct and its Accessory Canals , 1977, The Annals of otology, rhinology & laryngology. Supplement.

[16]  C. Muren,et al.  Anatomic Variations of the Cochlea and Relations to other Temporal Bone Structures , 1990, Acta radiologica.

[17]  H. Rask-Andersen,et al.  The Vestibular Aqueduct and the Para-Vestibular Canal , 1974, Acta radiologica: diagnosis.

[18]  Bernard Fraysse,et al.  The Size of the Cochlea and Predictions of Insertion Depth Angles for Cochlear Implant Electrodes , 2006, Audiology and Neurotology.

[19]  Luboš Voldřich,et al.  Correlative study of sensory cell density and cochlear length in humans , 1987, Hearing Research.

[20]  G M Clark,et al.  Cochlear view: postoperative radiography for cochlear implantation. , 2000, The American journal of otology.