μRALP and Beyond: Micro-Technologies and Systems for Robot-Assisted Endoscopic Laser Microsurgery

Abstract

Laser microsurgery is the current gold standard surgical technique for the treatment of selected diseases in delicate organs such as the larynx. However, the operations require large surgical expertise and dexterity, and face significant limitations imposed by available technology, such as the requirement for direct line of sight to the surgical field, restricted access, and direct manual control of the surgical instruments. To change this status quo, the European project μRALP pioneered research towards a complete redesign of current laser microsurgery systems, focusing on the development of robotic micro-technologies to enable endoscopic operations. This has fostered awareness and interest in this field, which presents a unique set of needs, requirements and constraints, leading to research and technological developments beyond μRALP and its research consortium. This paper reviews the achievements and key contributions of such research, providing an overview of the current state of the art in robot-assisted endoscopic laser microsurgery. The primary target application considered is phonomicrosurgery, which is a representative use case involving highly challenging microsurgical techniques for the treatment of glottic diseases. The paper starts by presenting the motivations and rationale for endoscopic laser microsurgery, which leads to the introduction of robotics as an enabling technology for improved surgical field accessibility, visualization and management. Then, research goals, achievements, and current state of different technologies that can build-up to an effective robotic system for endoscopic laser microsurgery are presented. This includes research in micro-robotic laser steering, flexible robotic endoscopes, augmented imaging, assistive surgeon-robot interfaces, and cognitive surgical systems. Innovations in each of these areas are shown to provide sizable progress towards more precise, safer and higher quality endoscopic laser microsurgeries. Yet, major impact is really expected from the full integration of such individual contributions into a complete clinical surgical robotic system, as illustrated in the end of this paper with a description of preliminary cadaver trials conducted with the integrated μRALP system. Overall, the contribution of this paper lays in outlining the current state of the art and open challenges in the area of robot-assisted endoscopic laser microsurgery, which has important clinical applications even beyond laryngology.

Keywords: augmented reality; cancer imaging; cognitive surgical system; computer-assisted surgery; flexible robotic endoscope; laser microsurgery; micro-robot; surgeon-robot interface.

FIGURE 1

User interfaces for laser surgery. (A) Elevate ENT handpiece, an optical scalpel commercialized by OmniGuide Surgical. (B) EasySpot Hybrid, a manual laser micromanipulator by DEKA for surgical microscopes. (C) Intuitive Surgical’s da Vinci system and (D) Medrobotics Flex robotic system, both of which can include an optical fiber for laser surgeries. (E) K.U. Leuven’s interface for robot-aided laser surgery based on a graphics tablet (Tang et al., 2006). (F) IIT’s Virtual Scalpel interface based on a tablet PC (Mattos et al., 2011). (G) µRALP’s Virtual Microscope and tablet-based laser controller (Deshpande et al., 2014).

FIGURE 2

Core technologies of endoscopic laser microsurgery systems reviewed in this paper. These technologies can be integrated to create advanced robotic systems for delicate and high precision operations, such as demonstrated by the µRALP system for robot-assisted laser phonomicrosurgery shown on the right (Tavernier et al., 2017).

FIGURE 3

Micro-robotic laser micromanipulators developed during µRALP. (A) Squipabot (Rabenorosoa et al., 2014). (B) PIBOT (Lescano, 2015). (C) Micro Agile-Eye (Lescano, 2015).

FIGURE 4

Magnetically actuated laser scanners for endoscopic microsurgery. (A) Concept (B) Prototype based on a standard silicon optical fiber (Acemoglu et al., 2019). (C) Prototype based on a CO₂ laser waveguide (Acemoglu and Mattos, 2018).

FIGURE 5

Further laser steering devices for endoscopic surgery. (A) A biocompatible conducting polymer continuum robot (Chikhaoui et al., 2018) (B) A flexible steerable instrument (O’Brien et al., 2019). (C) A cable-driven parallel robotic system (Zhao et al., 2020). (D) A millimeter-scale tip/tilt laser-steering system (Bothner et al., 2019). (E) Microrobotic laser steering system (York et al., 2021).

FIGURE 6

(A) Extensible hollow core continuum robot for non-contact laser surgery (Kundrat et al., 2019). (B) High power laser auto-focusing system based on a hydraulically actuated MEMS varifocal mirror (Geraldes et al., 2019).

FIGURE 7

(A) the µRALP endoscope tip with integrated dual imaging system (Tavernier et al., 2017). (B) and (C) white-light images acquired at 600 fps. (D) Fluorescence image acquired with the same imaging bundle.

FIGURE 8

The µRALP teleoperation interface and its components (Deshpande et al., 2014).

FIGURE 9

Examples of intra-operative planning of incisions paths, ablation patterns, and safety regions based on graphic overlays (Deshpande et al., 2014). The high-power surgical laser was only enabled within the defined safe region.

FIGURE 10

(A) Schematic view of a trifocal laser visual servoing system with two cameras (Tamadazte et al., 2018). (B) Trajectory following test on a 2D surface (Seon et al., 2015). (C) Intraoperative scene during laser visual servoing on the vocal cord of a cadaver (Andreff and Tamadazte, 2016).

FIGURE 11

The Haptic Laser Scalpel, developed to bring the sense of haptics to contactless laser surgeries (Olivieri et al., 2018). (A) Surgeon interface (B) 3D visualization of the surgical site with a virtual haptic scalpel avatar.

FIGURE 12

Real-time stereoscopic methods for (A) 3D reconstruction (Schoob et al., 2015). (B) intraoperative incision planning and visualization (Schoob et al., 2017), and (C) laser focus adjustment (Schoob et al., 2016).

FIGURE 13

Results from research on cognitive modeling and control of laser-tissue interactions. (A) Real-time estimate of superficial tissue temperature during high-power laser scanning (Pardo et al., 2014). (B) Autonomous laser incision depth control along incision paths (Acemoglu et al., 2019). (C) Autonomous tissue volume vaporization by laser ablation (Fichera et al., 2015b). (D) Augmented reality gauge for displaying the laser incision depth progression in real-time (Fichera et al., 2016).

FIGURE 14

The integrated µRALP surgical system prototype under evaluation in a human cadaver (Tavernier et al., 2017).