Benoît Herman

Building Large Mosaics of Confocal Edomicroscopic Images Using Visual Servoing

Probe-based confocal laser endomicroscopy provides real-time microscopic images of tissues contacted by a small probe that can be inserted in vivo through a minimally invasive access. Mosaicking consists in sweeping the probe in contact with a tissue to be imaged while collecting the video stream, and process the images to assemble them in a large mosaic. While most of the literature in this field has focused on image processing, little attention has been paid so far to the way the probe motion can be controlled. This is a crucial issue since the precision of the probe trajectory control drastically influences the quality of the final mosaic. Robotically controlled motion has the potential of providing enough precision to perform mosaicking. In this paper, we emphasize the difficulties of implementing such an approach. First, probe-tissue contacts generate deformations that prevent from properly controlling the image trajectory. Second, in the context of minimally invasive procedures targeted by our research, robotic devices are likely to exhibit limited quality of the distal probe motion control at the microscopic scale. To cope with these problems visual servoing from real-time endomicroscopic images is proposed in this paper. It is implemented on two different devices (a high-accuracy industrial robot and a prototype minimally invasive device). Experiments on different kinds of environments (printed paper and ex vivo tissues) show that the quality of the visually servoed probe motion is sufficient to build mosaics with minimal distortion in spite of disturbances.

Laparoscopic optical biopsies: In vivo robotized mosaicing with probe-based confocal endomicroscopy

Probe-based confocal laser endomicroscopy is a promising technology for performing minimally-invasive optical biopsies. With the help of mosaicing algorithms, several studies reported successful results in endoluminal surgery. In this paper, we present a prototype for making robotized optical biopsies on a variety of organs inside the abdominal cavity. We chose a macro-micro association, with a macropositioner, a micropositioner and a passive mechanical compensation of physiological motion. The probe is actuated by three hydraulic micro-balloons and can be moved on the surface of an organ to generate a mosaic. This paper presents the design and experimental results of a first in vivo trial on a porcine model.

Mechatronic design of a hand-held instrument with active trocar for laparoscopy

Instruments used in many types of minimally invasive procedures, in particular laparoscopy, are rigid or only limitedly flexible and some tasks like suturing are difficult to perform with them. A novel hand-held, lightweight and ergonomic mechatronic instrument is presented in this paper. The instrument has a 3-DOF roll-pitch-roll end-effector controlled using an easy to use handle that provides the surgeon with a 6-DOF movement, including a distal circular movement which resembles the circular movement of stitching. The design of the instrument is based on a global study involving control, dexterity and ergonomic aspects, with the aim of developing an instrument that enhances the dexterity of the surgeon while having an intuitive and ergonomic interface. A proof of concept prototype was built and tested in vitro and in vivo.

Development and first in vivo trial of Evolap, an active laparoscope positioner.

To determine essential specifications for an active endoscope holder, a survey of laparoscopic procedures was conducted. A review of the literature highlighted the advantages and limitations of existing scope-holding systems. From this analysis, basic requirements were listed for such devices. Pursuant to this, an ergonomic and user-friendly laparoscope manipulator was designed to assist the surgeon. A first in vivo procedure demonstrated feasibility of the device and its value in clinical practice, enabling surgeons to work more comfortably.

Optimization of concentric-tube robot design for deep anterior brain tumor surgery

Most of existing works on the tubes design optimization of concentric-tube robot (CTR) do not include the elastic stability in the optimization criteria. The only work which formulates the elastic stability in the objective function is based on scalarization method which is used in existing multi-objective design optimization. The objective function is formed by a set of weighted objective functions. The selection of the weights is crucial as the optimization results are greatly affected by them and could be misleading if these weights are improperly chosen. As an alternative optimization technique, we use Pareto grid-searching method to avoid this problem and allow a straightforward interpretation of the results following the selection criteria for the parameters to be optimized. This paper shows a three-tube CTR design based on Pareto grid-searching method in order to optimize the reachability and elastic stability of the CTR within a specific curvature range dedicated to the deep anterior brain tumor removal surgery.

Requirements analysis and preliminary design of a robotic assistant for reconstructive microsurgery.

Microanastomosis is a microsurgical gesture that involves suturing two very small blood vessels together. This gesture is used in many operations such as avulsed member auto-grafting, pediatric surgery, reconstructive surgery - including breast reconstruction by free flap. When vessels have diameters smaller than one millimeter, hand tremors make movements difficult to control. This paper introduces our preliminary steps towards robotic assistance for helping surgeons to perform microanastomosis in optimal conditions, in order to increase gesture quality and reliability even on smaller diameters. A general needs assessment and an experimental motion analysis were performed to define the requirements of the robot. Geometric parameters of the kinematic structure were then optimized to fulfill specific objectives. A prototype of the robot is currently being designed and built in order to providing a sufficient increase in accuracy without prolonging the duration of the procedure.