HelixFlex : bioinspired maneuverable instrument for skull base surgery
In 2013 I joined as visiting research fellow the lab of Prof. Paul Breedveld at the bio-mechanical department of in TU Delft (The Netherlands) where I worked on the design and development of a new instrument for improving dexterity during endonasal skull surgery. This experience taught me a lot about mechanical design and instrument manufacturing.
Endoscopic surgical treatment of most skull base pathologies, including certain pituitary tumors, is severely impaired by current instruments lack of maneuverability. In this context there is the need for instruments that are able to provide a stable shaft position, while both the orientation and the position of the end-effector can be independently controlled.
Conventional steerable designs, based on rigid links and hinged mechanisms, are best comparable with nature’s endo- or exoskeleton approach. These conventional designs have proven to be highly effective at large dimensions, as for example in the scales of an excavator. At the smaller dimensions needed for minimally invasive surgery, however, the fabrication of such hinged structures becomes increasingly difficult. The muscular hydrostatic skeleton in the arms of Loliginid squid consists out of differently orientated muscle layers (see Figure). Simultaneous contraction of these muscle layers results in a flexible, fluent motion. This led to the development of a new principle of steering via simultaneous actuation of multiple, differently orientated cable layers.
Inspired by nature’s hydrostatic skeleton approach, the multi-maneuverable tip of the HelixFlex consists of a single compliant segment, and incorporates three different cable layers: one with parallel cables and two with helically-oriented cables.
Simultaneous actuation of cable layers is accomplished via a similarly shaped joystick in the handle of the instrument. By manually controlling this joystick, the user can control the movement of HelixFlex’ tip in four Degrees of Freedom, resulting in a fluent motion that greatly reflects the motion of squid tentacles (check out this movie of the Helixflex skillfully maneuvered by Prof. Breedveld)
Gerboni, G., Henselmans, P.W.J., Arkenbout, E.A., van Furth, W.R., Breedveld, P. (2015), “HelixFlex: A Bioinspired Maneuverable Instrument for Skull Base Surgery.”Bioinspiration & Biomimetics 10, no. 6, 066013
Patent : WO 2015105421 A1, title "Industrial or medical tool with steering cables", inventors: P. Breedveld, P. Henselmans, G. Gerboni, E. Arkenbout, W. F. Wouter.
More info on BITE group website