Comparison on intracochlear disturbances between drilling a manual and robotic cochleostomy

Abstract

In hearing preservation cochlear implantation (HPCI), it is considered that minimizing disturbances in hearing organ are likely to reduce trauma and protection of the underlying endosteal membrane of the cochlea is an important factor in cochleostomy formation. The robotic micro-drill system tested in this paper is the first example of an autonomous surgical drill successfully producing a cochleostomy, which keeps the underlying endosteal membrane intact. This study compares induced vibrations within the cochlea during formation of the cochleostomy between using the robotic micro-drill and conventional manual drilling. The vibration of the endosteal membrane is measured using a Microscope Scanning Vibrometer (MSV) at a third window, produced in the cochlea. Results show that the highest velocity amplitude measured was associated with the manual drilling. The robotic micro-drill produced only about 1% of the peak velocity amplitude seen in manual drilling and exhibited much more uniform behaviour, while keeping the underlying membrane intact. The technique applied when using the robotic drill could be a major step in reducing the trauma to the cochlea, by reducing disturbance levels.