Philippe Cinquin

Mediatorless high-power glucose biofuel cells based on compressed carbon nanotube-enzyme electrodes

Enzymatic fuel cells use enzymes to produce energy from bioavailable substrates. However, such biofuel cells are limited by the difficult electrical wiring of enzymes to the electrode. Here we show the efficient wiring of enzymes in a conductive pure carbon nanotube matrix for the fabrication of a glucose biofuel cell (GBFC). Glucose oxidase and laccase were respectively incorporated in carbon nanotube disks by mechanical compression. The characterization of each bioelectrode shows an open circuit potential corresponding to the redox potential of the respective enzymes, and high current densities for glucose oxidation and oxygen reduction. The mediatorless GBFC delivers a high power density up to 1.3 mW cm−2 and an open circuit voltage of 0.95 V. Moreover, the GBFC remains stable for 1 month and delivers 1 mW cm−2 power density under physiological conditions (5×10−3 mol l−1 glucose, pH 7). To date, these values are the best performances obtained for a GBFC.

Computer-Assisted Spine Surgery: A Technique for Accurate Transpedicular Screw Fixation Using CT Data and a 3-D Optical Localizer

The computer-assisted spine surgery system presented in this paper follows the basic ideas which have been developed for computer-assisted medical interventions (CAMI) in our lab since 1985. There are three steps to insert a linear tool inside vertebral pedicles. First, the surgeon defines an optimal trajectory on pre-operative computed tomography. Second, this trajectory is reported in the operating room coordinate system using an intra-operative sensor and a registration algorithm. Third, a guiding system helps the surgeon follow the selected trajectory. In this paper, we present an implementation of this method that uses only a 3-dimensional optical localizer. Results on cadaver specimens and on the first seven patients are presented.

Single Glucose Biofuel Cells Implanted in Rats Power Electronic Devices

We describe the first implanted glucose biofuel cell (GBFC) that is capable of generating sufficient power from a mammals body fluids to act as the sole power source for electronic devices. This GBFC is based on carbon nanotube/enzyme electrodes, which utilize glucose oxidase for glucose oxidation and laccase for dioxygen reduction. The GBFC, implanted in the abdominal cavity of a rat, produces an average open-circuit voltage of 0.57 V. This implanted GBFC delivered a power output of 38.7 μW, which corresponded to a power density of 193.5 μW cm−2 and a volumetric power of 161 μW mL−1. We demonstrate that one single implanted enzymatic GBFC can power a light-emitting diode (LED), or a digital thermometer. In addition, no signs of rejection or inflammation were observed after 110 days implantation in the rat.

Image guided operating robot: a clinical application in stereotactic neurosurgery

Describes a system based on the combined use of medical imaging and robot positioning used in stereotactic neurosurgery. The types of interventions performed with the help of this system require a high precision (less than 1 millimeter) of positioning with respect to the patients brain with no direct visibility of the target; they are executed through a hole in the skull of 2.3 millimeters. A typical example is the placement of a stimulating electrode in a particular nucleus of the thalamus for patients suffering from Parkinsons disease. These interventions rely on the intensive use of medical imaging to define the operative strategy. The target is defined with respect to the images. A six-axis robot whose end-effector is a linear guide automatically reaches a configuration generated such that if the surgical instrument (needle, electrode, etc.) is introduced in the guide, the surgeon reaches the target using a linear displacement of the instrument. This system is operational and is in routine clinical use.<<ETX>>

A new robot architecture for tele-echography

This paper presents a slave robot carrying an ultrasound probe for remote echographic examination. This robot is integrated in a master-slave system called robotic tele-echography (TER). The system allows an expert operator to perform a remote diagnosis from echographic data he acquires on a patient located in a distant place. The originality of this robot lies in its architecture: the cable-driven robot is lightweight and semirigid, and it is positioned on the patient body. In this paper, we describe the clinical application, the system architecture, the second implementation of the robot, and experiments performed with this prototype.

Accurate calibration of cameras and range imaging sensor: the NPBS method

A method is presented for modeling and calibration of sensors, to reach an accuracy similar in magnitude to the resolution of the sensors. The authors focus on camera and range image calibration. They show the limitations of existing methods, and present an approach and camera calibration using mathematical B-Spline functions. This method is abbreviated as NPBS (N-Planes B-Spline). It is an extension of the two-planes method, but relies on pure mathematical modeling based on spline approximation theory. The mathematical modeling is combined with a calibration device that enables accurate data acquisition to calibrate a camera and a light plane independently. Experimental results are presented showing accuracy on the determination of a scattered plane.<<ETX>>

Computer-Assisted Knee Anterior Cruciate Ligament Reconstruction: First Clinical Tests

Anterior cruciate ligament reconstruction is a delicate task. The procedure of choice is the patellar tendon bone autograft, but an anisometric position of this tendon often leads to failure. We propose a method that allows positioning of the central part of the ligament graft at the least anisometric sites. The system uses a workstation and a three-dimensional optical localizer to create images that represent knee kinematics. The surgeon uses these images to guide the surgery. This technique has been validated on eight cadavers and 12 patients.

Computer-assisted spine surgery

When inserting screws into a vertebral pedicle, the surgeon usually exposes the back part of the vertebra and uses his or her anatomic knowledge to align the drill in the proper direction. A slight error in direction may result in an important error in the position of the tip of the screw. This is done with no direct visibility of crucial structures (spinal cord, pleura, vessels). Statistical analysis of a series of surgical procedures has shown that 10% to 40% of the screws are not installed correctly. To reduce the risk of complication, a computer assisted method is proposed that enables the surgeon to place a screw at a position preoperatively defined in 3 dimensions using computed tomography images. This allows the surgeon to align a standard surgical drill with the optimal position and direction. The depth of the pilot hole during drilling also is monitored by the system to prevent penetration of the anterior cortex of the vertebral body. Using this procedure, in vitro tests were performed and showed that an accuracy of less than 1 mm can be obtained. Clinical trials were done in 10 patients who suffered severe scoliosis or spondylolisthesis. The trajectory of the holes drilled in L2, L3, L4, and L5 vertebrae were checked for all clinical tests. Postoperative radiographs and computed tomography scans showed that the screws were well inserted in each plane for each pedicle. This technique also can be used to perform osteosynthesis at the thoracic and cervical levels.

Automated 3‐dimensional computed tomographic and fluoroscopic image registration

The registration of 3-dimensional (3-D) anatomical surfaces to sensor data such as intraoperative fluoroscopy is one of the basic problems in computer integrated surgery. The main objective is to find the relationship between 3-D preoperative computed tomographic images and a pair of intraoperative fluoroscopic images. Consequently, surgical navigation devices can use this relationship to provide improved surgical guidance. The proposed registration strategy presents a noninvasive anatomy-based (frameless) method for registration. In this article, we propose a cooperative approach between registration and contour segmentation on fluoroscopy. This approach is based on the duality between registration and segmentation in a model-based vision system. It associates a likelihood value to each pixel that corresponds to the probability that the pixel belongs to the contour of the object of interest. The registration is then achieved between backprojection lines stemming from likely contour pixels and the 3-D surface model of the object of interest. Then, in order to take into account the internal contour points extracted by the cooperative approach, we propose a new line to surface distance computation algorithm to be used during the data to model distance minimization step. Finally, we present the obtained results that demonstrate the validity of the proposed approach in carrying out accurate 3-D and 2-D registration.

Matching Of Medical Images For Computed And Robot Assisted Surgery

This paper adresses the application of matching techniques to Computer and Robot Assisted Surgery, where we desire to use in the surgical theater a treatment planning based on multi-modal data (mainly pre-operative images). We present a methodology based on geometrical matching of reference anatomical surfaces. Then we describe a new general method that enables to perform 3-D / 2-D matching and 3-D / 3-D matching with fast computation. Results are illustrated.