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Cochlear duct length and cochlear distance on preoperative CT: imaging markers for estimating insertion depth angle of cochlear implant electrode

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An Editorial Comment to this article was published on 01 February 2021

Abstract

Objectives

Preoperative estimation of the insertion depth angle of cochlear implant (CI) electrodes is essential for surgical planning. The purpose of this study was to determine the cochlear size using preoperative CT and to investigate the correlation between cochlear size and insertion depth angle in morphologically normal cochlea.

Methods

Thirty-five children who underwent CI were included in this study. Cochlear duct length (CDL) and the diameter of the cochlear basal turn (distance A/B) on preoperative CT and the insertion depth angle of the CI electrode on postoperative radiographs were independently measured by two readers. Correlation between cochlear size and insertion depth angle was evaluated. Interobserver agreement was calculated using the intraclass correlation coefficient (ICC).

Results

The mean CDL, distance A, and distance B of 70 ears were 36.20 ± 1.57 mm, 8.67 ± 0.42 mm, and 5.73 ± 0.32 mm, respectively. The mean insertion depth angle was 431.45 ± 38.42°. Interobserver agreements of CDL, distance A/B, and insertion depth angle were fair to excellent (ICC 0.864, 0.862, 0.529, and 0.958, respectively). Distance A (r = − 0.7643) and distance B (r = − 0.7118) showed a negative correlation with insertion depth angle, respectively (p < 0.0001). However, the correlation between CDL and insertion depth angle was not statistically significant (r = − 0.2333, p > 0.05).

Conclusions

The CDL and cochlear distance can be reliably obtained from preoperative CT. Distance A can be used as a predictive marker for estimating insertion depth angle during CI surgery.

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Abbreviations

BTL:

Length of the cochlear basal turn

CDL:

Cochlear duct length

CI:

Cochlear implantation

CT:

Computed tomography

ICC:

Intraclass correlation coefficient

TBCT:

Temporal bone computed tomography

References

  1. Wanna GB, Noble JH, Gifford RH et al (2015) Impact of intrascalar electrode location, electrode type, and angular insertion depth on residual hearing in cochlear implant patients: preliminary results. Otol Neurotol 36:1343–1348

    Article  Google Scholar 

  2. Hochmair I, Arnold W, Nopp P, Jolly C, Müller J, Roland P (2003) Deep electrode insertion in cochlear implants: apical morphology, electrodes and speech perception results. Acta Otolaryngol 123:612–617

    PubMed  Google Scholar 

  3. Hochmair I, Hochmair E, Nopp P, Waller M, Jolly C (2015) Deep electrode insertion and sound coding in cochlear implants. Hear Res 322:14–23

    Article  Google Scholar 

  4. Roy AT, Penninger RT, Pearl MS et al (2016) Deeper cochlear implant electrode insertion angle improves detection of musical sound quality deterioration related to bass frequency removal. Otol Neurotol 37:146–151

    Article  Google Scholar 

  5. O’Connell BP, Cakir A, Hunter JB et al (2016) Electrode location and angular insertion depth are predictors of audiologic outcomes in cochlear implantation. Otol Neurotol 37:1016

    Article  Google Scholar 

  6. Adunka O, Kiefer J (2006) Impact of electrode insertion depth on intracochlear trauma. Otolaryngol Head Neck Surg 135:374–382

    Article  Google Scholar 

  7. Welling DB, Hinojosa R, Gantz BJ, Lee JT (1993) Insertional trauma of multichannel cochlear implants. Laryngoscope 103:995–1001

    Article  CAS  Google Scholar 

  8. Gstoettner W, Pok S, Peters S, Kiefer J, Adunka O (2005) Cochlear implantation with preservation of residual deep frequency hearing. HNO 53:784–790

    Article  Google Scholar 

  9. Erixon E, Rask-Andersen H (2013) How to predict cochlear length before cochlear implantation surgery. Acta Otolaryngol 133:1258–1265

    Article  Google Scholar 

  10. Dimopoulos P, Muren C (1990) Anatomic variations of the cochlea and relations to other temporal bone structures. Acta Radiol 31:439–444

    Article  CAS  Google Scholar 

  11. Avci E, Nauwelaers T, Lenarz T, Hamacher V, Kral A (2014) Variations in microanatomy of the human cochlea. J Comp Neurol 522:3245–3261

    Article  Google Scholar 

  12. Hardy M (1938) The length of the organ of Corti in man. Am J Anat 62:291–311

    Article  Google Scholar 

  13. Kawano A, Seldon HL, Clark GM (1996) 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. Ann Otol Rhinol Laryngol 105:701–709

    Article  CAS  Google Scholar 

  14. Ketten DR, Skinner MW, Wang G, Vannier MW, Gates GA, Gail Neely J (1998) In vivo measures of cochlear length and insertion depth of nucleus cochlear implant electrode arrays. Ann Otol Rhinol Laryngol Suppl 175:1–16

  15. Meng J, Li S, Zhang F, Li Q, Qin Z (2016) Cochlear size and shape variability and implications in cochlear implantation surgery. Otol Neurotol 37:1307–1313

    Article  Google Scholar 

  16. Würfel W, Lanfermann H, Lenarz T, Majdani O (2014) Cochlear length determination using cone beam computed tomography in a clinical setting. Hear Res 316:65–72

    Article  Google Scholar 

  17. Escudé B, James C, Deguine O, Cochard N, Eter E, Fraysse B (2006) The size of the cochlea and predictions of insertion depth angles for cochlear implant electrodes. Audiol Neurootol 11:27–33

    Article  Google Scholar 

  18. Koch RW, Ladak HM, Elfarnawany M, Agrawal SK (2017) Measuring cochlear duct length–a historical analysis of methods and results. J Otolaryngol Head Neck Surg 46:19

    Article  Google Scholar 

  19. Catmull E, Rom R (1974) A class of local interpolating splines. In: Computer aided geometric design. Academic Press, New York, pp 317–326

  20. Yuksel C, Schaefer S, Keyser J (2011) Parameterization and applications of Catmull–Rom curves. Comput Aided Des 43:747–755

    Article  Google Scholar 

  21. Alexiades G, Dhanasingh A, Jolly C (2015) Method to estimate the complete and two-turn cochlear duct length. Otol Neurotol 36:904–907

    Article  Google Scholar 

  22. Xu J, Xu S-A, Cohen LT, Clark GM (2000) Cochlear view: postoperative radiography for cochlear implantation. Otol Neurotol 21:49–56

    CAS  Google Scholar 

  23. Svrakic M, Friedmann DR, Berman PM, Davis AJ, Roland JT Jr, Svirsky MA (2015) Measurement of cochlear implant electrode position from intraoperative post-insertion skull radiographs: a validation study. Otol Neurotol 36:1486

    Article  Google Scholar 

  24. Rivas A, Cakir A, Hunter JB et al (2017) Automatic cochlear duct length estimation for selection of cochlear implant electrode arrays. Otol Neurotol 38:339–346

    Article  Google Scholar 

  25. Iyaniwura JE, Elfarnawany M, Riyahi-Alam S et al (2017) Intra- and interobserver variability of cochlear length measurements in clinical CT. Otol Neurotol 38:828–832

    Article  Google Scholar 

  26. Iyaniwura JE, Elfarnawany M, Ladak HM, Agrawal SK (2018) An automated A-value measurement tool for accurate cochlear duct length estimation. J Otolaryngol Head Neck Surg 47:1–8

    Article  Google Scholar 

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Acknowledgments

The authors would like to thank Prof. Sang Joon Park for his support to quantitative image analysis and Professor Emeritus In-One Kim for his support to manuscript editing.

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None.

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Authors and Affiliations

  1. Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro, Jongro-gu, Seoul, 03080, South Korea

    Jiseon Oh, Jung-Eun Cheon, Junghoan Park, Young Hun Choi, Yeon Jin Cho & Seunghyun Lee

  2. Institute of Radiation Medicine, SNUMRC (Seoul National University Medical Research Center), Seoul, South Korea

    Jung-Eun Cheon, Young Hun Choi, Yeon Jin Cho & Seunghyun Lee

  3. Department of Otorhinolaryngology-Head & Neck Surgery, Seoul National University College of Medicine, Seoul, South Korea

    Seung Ha Oh

  4. Department of Radiology, Seoul National University Seoul Metropolitan Government Boramae Medical Center, Seoul, South Korea

    Su-Mi Shin & Sun-Won Park

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  1. Jiseon Oh
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  4. Young Hun Choi
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Corresponding author

Correspondence to Jung-Eun Cheon.

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Jung-Eun Cheon.

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Statistics and biometry

No complex statistical methods were necessary for this paper.

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Written informed consent was waived by the Institutional Review Board.

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Institutional Review Board approval was obtained.

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• retrospective

• observational study

• performed at one institution

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Oh, J., Cheon, JE., Park, J. et al. Cochlear duct length and cochlear distance on preoperative CT: imaging markers for estimating insertion depth angle of cochlear implant electrode. Eur Radiol 31, 1260–1267 (2021). https://doi.org/10.1007/s00330-020-07580-4

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  • DOI: https://doi.org/10.1007/s00330-020-07580-4

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