Image-guidance and robotic technology to support surgery on the lateral skull base

The lateral skull base embeds important anatomy such as the hearing and balance organs, facial and taste nerves as well as blood supply for the brain, many of which structures are at submillimetric scale. Surgery at the lateral skull base is at the limits of human perception and dexterity, thus increasing chances for side effects and complications such as destruction of residual hearing or nerves. The geometric scale and fragility of lateral skull base anatomy requires constant visual access, and dexterity with haptic feedback with resolutions of <<0.5 mm (Krombach et al. 2005) and <<1mN (Schurzig et al. 2010) respectively. To overcome human limitations and improve surgical outcomes, the use of image based 1) intervention planning for 2) image-guidance of surgical tools and 3) surgical robotic systems that can carry out tasks at this scales automatically, manipulate in the micrometer range and feel in the micronewton range has been proposed. Software based annotation of anatomical structures in lateral skull base (Nobel et al. 2009), planning of cochlear access procedures (Klenzner et al. 2014, Gerber et al. 2014) and elements of photo realistic rendering (Tsai et al. 2019) have been proposed and made their way to clinics. In contrast, commercially available ENT navigation systems have been demonstrated to be of very limited use due to inaccuracies present (Labadie et al. 2004, Majdani et al. 2009). Robotic technology has been proposed and investigated for automated drilling and milling tasks in the temporal bone (Baron et al. 2010, Bell et al. 2012) with successful clinical introduction (Weber & Caversaccio et al. 2017). In addition, head mounted and patient individual template systems have been successfully applied in clinics (Labadie et al. 2014). With this contribution, a general overview of the state of the art image-guidance and robotics for microsurgery in the lateral skull base will be given with an outlook of what can be expected in the near future.