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Biomedical subjects

Jocelyne Troccaz

Publications and source records attributed to Jocelyne Troccaz.

14 recordsLinked to original sources
PubMed2006

Prostate biopsies guided by three-dimensional real-time (4-D) transrectal ultrasonography on a phantom: comparative study versus two-dimensional transrectal ultrasound-guided biopsies.

OBJECTIVE: This study evaluated the accuracy in localisation and distribution of real-time three-dimensional (4-D) ultrasound-guided biopsies on a prostate phantom. METHODS: A prostate phantom was created. A three-dimensional real-time ultrasound system with a 5.9MHz probe was used, making it possible to see several reconstructed orthogonal viewing planes in real time. Fourteen operators performed biopsies first under 2-D then 4-D transurethral ultrasound (TRUS) guidance (336 biopsies). The biopsy path was modelled using segmentation in a 3-D ultrasonographic volume. Special software was used to visualise the biopsy paths in a reference prostate and assess the sampled area. A comparative study was performed to examine the accuracy of the entry points and target of the needle. Distribution was assessed by measuring the volume sampled and a redundancy ratio of the sampled prostate. RESULTS: A significant increase in accuracy in hitting the target zone was identified using 4-D ultrasonography as compared to 2-D. There was no increase in the sampled volume or improvement in the biopsy distribution with 4-D ultrasonography as compared to 2-D. CONCLUSION: The 4-D TRUS guidance appears to show, on a synthetic model, an improvement in location accuracy and in the ability to reproduce a protocol. The biopsy distribution does not seem improved.

Humans↗
PubMed2006

A discrete soft tissue model for complex anatomical environment simulations.

Among the current challenges in human soft tissue modeling for medical purposes, the ability to model complex anatomical structures, their interactions and to accurately simulate them with physical realism are in the forefront of research. This paper describes a discrete soft tissue model which is geared toward solving these challenges. In this model, objects can be described as volumetric or surfacic sets of nodes depending on the level of precision required. Nodes have their own physical properties and a definition of their neighborhood. All these objects are submitted both to internal cohesive forces and to external attractive or interaction forces with other objects. Volume preservation is insured by a constraint. The model is applied to the simulation of the prostate and its surrounding organs.

Computer Simulation↗
PubMed2006

[Use of robotics in laparoscopic urological surgery: state of the art].

OBJECTIVE: To evaluate the current place of robotics in laparoscopic urological surgery. MATERIAL AND METHODS: A review of the international literature was conducted to evaluate the various available endoscope robot systems and telemanipulator robots and to establish their practical limitations and their contribution to surgery. RESULTS: Robotic systems are based on various structures, which each present specific disadvantages. Two types of systems can be distinguished: endoscope robots and telemanipulator robots (complete robotic systems) with different degrees of complexity, dimensions and costs. Each system is different in terms of service rendered. Endoscope robot systems (EndoAssist, AESOP, LapMan) are reliable and eliminate the need for an assistant to hold the camera. Man-machine interfaces can be manual, by pedal or by voice recognition. They are relatively large and expensive, limiting their diffusion at the present time. Complete instrument-handling robots (master-slave manipulators) are currently represented by 2 robots (Zeus and Da Vinci) which have demonstrated their efficacy in many difficult operations. Their very high cost and their large dimensions also constitute limitations to their diffusion, making them inaccessible to the majority of centres. The urological community has largely contributed to the evaluation of robots in laparoscopic operations, as reflected by the large number of publications. CONCLUSION: Considerable technological progress has been made over recent years to make laparoscopic surgery more accessible. Current robotized tools are still imperfect systems, but, in the future, may possibly facilitate difficult laparoscopic operations, particularly in urology.

Equipment Design↗
PubMed2006

[Preclinical development of the TIMC LER (light endoscope robot)].

INTRODUCTION: The authors participated in the development of an innovative endoscope robot in laparoscopic surgery designed by TIMC-GMCAO, providing a solution to the disadvantages of currently available systems, i.e. their cost and large dimensions. MATERIAL AND METHODS: A compact robot (LER) placed on the patient's skin that can be used in the lateral and dorsal supine position was tested on cadavres and laboratory pigs in order to allow successive modifications. The current control system is based on voice recognition. The amplitude of vision is 360 degrees with an angle of 160 degrees. Twenty three procedures were performed (2 radical prostatectomies, 4 pelvic lymph node dissections, 6 nephrectomies, 2 adrenalectomies, 3 cholecystectomies, 1 small bowel resection-anastomosis, 1 cystectomy, 1 splenectomy, and 3 appendicectomies). RESULTS: Among the various control systems tested, we adopted voice recognition on the basis of its intuitive nature and the fact that it leaves one hand free. In the light of these studies, several aspects of the prototype were modified: reliability, fixation, ergonomy and dimensions. The ease of installation, which takes only 5 minutes, and the easy handling of the robot allowed 21 out of 23 laparoscopic procedures to be performed without the need for an assistant. CONCLUSION: The LER robot is an endoscope robot guided by the surgeon's voice that can eliminate the need for an assistant to hold the camera during laparoscopic surgery in the lateral and dorsal supine positions. The ease of installation and manufacture should make this an effective and inexpensive system. The gain in operating time was not evaluated during these trials on cadavres and pigs, as various prototypes were tested and several problems of reliability were successively resolved. Ongoing randomized, prospective clinical trials should soon validate this robot prior to marketing.

Animals↗
PubMed2006

[Computer- and robot-assisted urological surgery].

The author reviews the computer and robotic tools available to urologists to help in diagnosis and technical procedures. The first part concerns the contribution of robotics and presents several systems at various stages of development (laboratory prototypes, systems under validation or marketed systems). The second part describes image fusion tools and navigation systems currently under development or evaluation. Several studies on computerized simulation of urological procedures are also presented.

Equipment Design↗
PubMed2005

CASPER, a Computer ASsisted PERicardial puncture system: first clinical results.

Pericardial puncture is the percutaneous insertion of a needle into the pericardial space to drain a pathological pericardial effusion. The challenge for the operating surgeon is to reach percutaneously a target zone in the vicinity of the mobile heart, in a soft-tissue environment. The surgeon's ability to accomplish this depends on his own mental picture of the effusion. CASPER is a navigation software using an optical localizer which assists the surgeon by enhancing the representation of the effusion and guiding the needle's progress. Using a localized and calibrated echographic probe, the surgeon acquires a set of images in the region of interest. This zone is then manually segmented on each image, a common zone is computed, and the surgeon defines a trajectory for the needle. During the puncture procedure, the surgeon follows the position of the localized needle on a computer monitor. After initial validation on an experimental phantom, a feasibility study was performed using canine and porcine models. The optical localization device was changed from an Optotrak to a Polaris device for easier use in the clinical setting. Prior to clinical application, various tests were performed concerning the mobility of the thoracic cage, the reproducibility of the thoracic position over several apneas, and the stability of anatomic structures relative to the thoracic cage. Finally, a first clinical application was successfully performed using this system. The present paper reports on these last two stages.

Echocardiography↗
PubMed2005

Development and testing of a compact endoscope manipulator for minimally invasive surgery.

OBJECTIVE: This report describes the design, development, and testing of a novel compact surgical assistant robot to control the orientation and insertion depth of a laparoscopic endoscope during minimally invasive abdominal surgery. In contrast to typical endoscope manipulators, the described robot is particularly compact and lightweight, is simple to set up and use, occupies no floor or operating table space, and does not limit access to the patient in any way. MATERIALS AND METHODS: The sterilizable endoscope manipulator is sufficiently small and lightweight at 625 g and 110 mm in diameter that it can be placed directly on the abdomen of the patient without interfering with other handheld instruments during minimally invasive surgery. It consists of an annular base, a clamp to hold an endoscope trocar, and two joints which enable azimuth rotation and inclination of the endoscope about a pivot point at the incision. The endoscope insertion depth is controlled by a cable winding acting against a compression spring on the endoscope shaft. Voice recognition and miniature keypad user command interfaces are provided, and the manipulator motors are backdriveable for manual repositioning. RESULTS: Endoscope camera trajectory-following accuracy and response-time results were measured using an optical localizer. Experimental results are given comparing the current prototype with the previous cable-driven prototype. The endoscope manipulator and its user interface were tested and evaluated by several surgeons during a series of minimally invasive surgical training procedures on cadavers and animals. CONCLUSIONS: The endoscope manipulator described has been shown to be a viable, practical device with performance and functionality equivalent to those of commercially available models, yet with greatly reduced size, weight, and cost.

Animals↗
PubMed2005

The mini-screen: an innovative device for computer assisted surgery systems.

In this paper we focus on the design of Computer Assisted Surgery (CAS) systems and more generally Augmented Reality (AR) systems that assist a user in performing a task on a physical object. Digital information or new actions are defined by the AR system to facilitate or to enrich the natural way the user would interact with the real environment. We focus on the outputs of such systems, so that additional digital information is smoothly integrated with the real environment of the user, by considering an innovative device for displaying guidance information: the mini-screen. We first motivate the choice of the mini-screen based on the ergonomic property of perceptual continuity and then present a design space useful to create interaction techniques based on a mini-screen. Two versions of a Computer ASsisted PERicardial (CASPER) puncture application, as well as a computer assisted renal puncture application, developed in our teams, are used to illustrate the discussion.

Computer Terminals↗
PubMed2004

MRI/TRUS data fusion for prostate brachytherapy. Preliminary results.

Prostate brachytherapy involves implanting radioactive seeds (I125 for instance) permanently in the gland for the treatment of localized prostate cancers, e.g., cT1c-T2a N0 M0 with good prognostic factors. Treatment planning and seed implanting are most often based on the intensive use of transrectal ultrasound (TRUS) imaging. This is not easy because prostate visualization is difficult in this imaging modality particularly as regards the apex of the gland and from an intra- and interobserver variability standpoint. Radioactive seeds are implanted inside open interventional MR machines in some centers. Since MRI was shown to be sensitive and specific for prostate imaging whilst open MR is prohibitive for most centers and makes surgical procedures very complex, this work suggests bringing the MR virtually in the operating room with MRI/TRUS data fusion. This involves providing the physician with bi-modality images (TRUS plus MRI) intended to improve treatment planning from the data registration stage. The paper describes the method developed and implemented in the PROCUR system. Results are reported for a phantom and first series of patients. Phantom experiments helped characterize the accuracy of the process. Patient experiments have shown that using MRI data linked with TRUS data improves TRUS image segmentation especially regarding the apex and base of the prostate. This may significantly modify prostate volume definition and have an impact on treatment planning.

Biophysical Phenomena↗
PubMed2004

A one-DOF freehand haptic device for robotic tele-echography.

Tele-echography may be an interesting alternative to conventional care when the medical expert is not close to the patient to be examined. In a system for tele-echography, medical expert proprioception and gesture feelings must be preserved to synchronize the ultrasound images with the motion made by the physician. It is why we develop a master-slave system for robotic tele-echography integrating force feedback. Because existing haptic devices are not fully adapted to this application--their workspace is often small and their basis is fixed--, we have developed a one-dimensional free-hand force feedback device. In this paper, we describe the design and a first evaluation of this new haptic device for robotic tele-echography.

France↗
PubMed2003

Robot-based tele-echography: the TER system.

This paper presents a master-slave robotized system enabling a remote echographic diagnosis. The expert holds a virtual probe placed on a haptic device; he moves this virtual probe in order to control the motion of the real probe positioned on the body of the patient located remotely. The real probe is placed on a lightweight and user-friendly slave robot and moved by it. The contact force between the probe and the patient is fed back to the operator allowing him to have a haptic virtual environment. The aim of this haptic control is to preserve the medical expert proprioception in order to the facilitate hand-eye coordination necessary to echographic examination. In this paper we present the architecture of the system and experimental results.

France↗
PubMed2002

Computer-aided hepatic tumour ablation: requirements and preliminary results.

Surgical resection of hepatic tumours is not always possible, since it depends on different factors, among which their location inside the liver functional segments. Alternative techniques consist in local use of chemical or physical agents to destroy the tumour. Radio frequency and cryosurgical ablations are examples of such alternative techniques that may be performed percutaneously. This requires a precise localisation of the tumour placement during ablation. Computer-assisted surgery tools may be used in conjunction with these new ablation techniques to improve the therapeutic efficiency, whilst they benefit from minimal invasiveness. This paper introduces the principles of a system for computer-assisted hepatic tumour ablation and describes preliminary experiments focusing on data registration evaluation. To keep close to conventional protocols, we consider registration of pre-operative CT or MRI data to intra-operative echographic data.

Humans↗
PubMed2002

A haptic virtual environment for tele-echography.

Having a haptic virtual environment for tele-echography will enable the medical expert with faster adaptation and especially facilitated immersion in what we could call a "virtual echographic examination cabinet". The innovation of this haptic control is to preserve medical expert proprioception and gesture feelings, which provide the users with indications that are synchronized with the echographic images. In this paper, we will focus on the telegesture module: we will detail several issues and solutions related to this particular problem of tele-robotic scan examination.

Communication↗