Force of Cochlear Implant Electrode Insertion Performed by a Robotic Insertion Tool

Abstract

Objective Robotic cochlear implant electrode array insertion offers substantial potential advantages, namely repeatability and minimization of insertion forces leading to decreased intracochlear trauma. Using such a robotic insertion tool, we sought to analyze force profiles during deployment of stylet-containing electrode arrays using either traditional insertion, in which the stylet is withdrawn after complete insertion of the electrode, or Advance Off-Stylet (AOS) insertion, in which the stylet is withdrawn simultaneous with electrode array insertion. Study design Prospective. Setting Tertiary referral center. Intervention(s) A robotic cochlear implant insertion tool coupled with a force sensing carriage was used to perform electrode array insertions into an anatomically-correct, 3-dimensional scala tympani model during either straight insertion (n=4) or AOS insertion (n=4). Main outcome measure(s) Both insertion techniques begin with a 7mm straight insertion during which forces were similar averaging approximately 0.006N. For insertion from 7–17mm, traditional insertion forces averaged 0.046 ± 0.027N with a peak of 0.093N and AOS insertion forces averaged 0.008 ± 0.006N with a peak of 0.034N. Beyond 9.74 mm, the difference between traditional and AOS insertion forces were highly significant. Conclusions With the use of a robotic insertion tool, which minimizes operator variability and maximizes repeatability, we have shown that cochlear implant electrode insertion via AOS is associated with lower average and maximum insertion forces, compared to traditional insertion. These findings support the use of AOS over traditional, straight insertion.

Characterization of Intracochlear Rupture Forces in Fresh Human Cadaveric Cochleae

“…9 Furthermore, preliminary data on electrode insertion forces generated during robotic insertion demonstrate significant differences between standard insertion techniques and those guided by stylets to avoid collision with the cochlear walls. 10 Prior to the work described herein, the clinical significance of these findings were speculative at best. We conclude that minimizing insertion forces will reduce the risk of translocation of a CI electrode array, and lead to improved audiological outcomes.…”

Postinsertional Cable Movements of Cochlear Implant Electrodes and Their Effects on Intracochlear Pressure

“…The development of atraumatic opening of the round window has led to the development of specific opening tools [6]. Insertional factors have been observed experimentally under force aspects [7] and even under the point of pressure occurrence in terms of speed [8], moisturized insertions [4], and tremor aspects [9]. Different studies have shown the clinical relevance of these findings [10–12].…”

Three-dimensional histological specimen preparation for accurate imaging and spatial reconstruction of the middle and inner ear

“…There are various reasons why CI surgery seems to be predestined for computer-assisted improvements regardless of whether the research is focussed on one or more of the steps involved in CI surgery, such as:milling the implant bed [24, 25, 72];performing the mastoidectomy [35, 36, 73, 98, 99, 116];performing the cochleostomy through a minimally invasive access [5–7, 20, 23, 51–53, 58, 64–66, 114]; orautomated insertion of the electrode array [42, 67, 79, 90, 91]. …”