The insertion speed of the CI electrode array essentially determines the insertion pressure

During electrode array insertion while cochlear implantation, the electrode array causes intense fluctuation in insertion pressure and therefore endocochlear mechanical trauma. Both, the impact of insertion speed on insertion pressure and the relationship between electrode insertion force and insertion pressure has not been investigated yet. In this study, the insertion pressure of a 31.5 mm standard cochlear electrode array was measured by a micro optical pressure sensor. The pressure measurement took place in a scala tympani model while recording the insertion force simultaneously. Insertion pressure und force have been acquired, depending on different insertion speeds (0.1, 0.5, 1.0, 1.5 and 2.0 mm/s). Within these experiments the insertion speed of 0.5 mm/s causes the lowest insertion pressure (0.73 ± 0.25 mmHg), the pressure rises to a maximum at 1.5 mm/s (1.08 ± 0.09 mmHg) and falls again at 2 mm/s (0.99 ± 0.08 mmHg). Similar patterns were observed for recorded insertion forces. These results assumed a high correlation between both insertion parameters. The present study reveals a non-linear increase in electrode array insertion pressure, when insertion speed raises, and a correlation between insertion pressure and insertion force. This dependence is a relevant future parameter to evaluate and reduce cochlear implant insertion trauma.

Poster-PDF A-1463.pdf

Publication History

Article published online:
13 May 2021