MISIT to empower minimally invasive surgeon with new protocols and innovative tools

Amsterdam 11 December 2000During the National Demonstration Day for Visualisation and Virtual Reality (VIS), which was organised by the Dutch Platform for High Performance Computing and Networking, the Delft University of Technology (DUT) showcased MISIT, a multi-disciplinary project on Minimally Invasive Surgery and Interventional Techniques. This extensive research programme consists of six separate sub-projects in which several faculties of the DUT are collaborating with a number of hospitals in The Netherlands, as well as the Dutch biomedical industry. The co-ordinating clinical partner in MISIT is the Academic Medical Centre (AMC), based in Amsterdam.

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The primary goal of MISIT is to optimise the surgical protocols as applied in minimally invasive surgery, a fairly young technique which still is in full development. The programme aims to reduce the negative effects and limitations as well as enhance the surgeon's overall performance in this type of surgery where a camera and special instruments are inserted via natural openings or small incisions in the patient's body. The procedure causes less pain and damage to the patient but requires advanced skills from the doctor, such as a great motoric dexterity and an optimised strategy to overcome the lack of feedback for a natural eye-hand co-ordination and the loss of control during catheter interventions over their mechanical steerability.

Within MISIT, both medical and technical disciplines have to be integrated to come up with technical solutions that can be accepted for clinical use in the operating theatre. The first sub-project therefore constitutes a task analysis to identify the bottlenecks in the pre- and per-operative surgical process and to determine the efficiency and safety of suggested new tools and methods in an evaluation study. Different image modalities, including endoscopy, x-ray, ultrasound, computed tomography (CT), and magnetic resonance (MRI) are applied to collect pre-operative data on the patient. The surgical process is quantitatively analysed through combined video-images, obtained from the laparoscope, a CCD camera, installed in the operating theatre, and relevant images from other sources to evaluate the interventions. The recordings will help the team search for improved protocols and tools where needed, as well as support the researchers in forecasting the effectiveness of new methods.

In the second sub-project, virtual reality techniques are used to improve the surgeon's eye-hand co-ordination. During minimally invasive procedures, the camera's line of sight produces 2D images of the operative field in which the surgeon has to perform a 3D task without having any tactile, proprioceptive nor olfactory cues. The MISIT team therefore wants to study the possibilities for introducing a 3D display of the patient data obtained from the camera, as well as a tele-manipulator, that has to enable the surgeon to directly control the camera. In addition, specific surgical instruments need to be developed for MIS interventions. The DUT researchers expect that the concept of tele-manipulation will only break through in the operating room within five to ten years from now.

The team also wants to integrate pre- and real time per-operative inner body data acquired from different modalities like CT, MRI, Single Photon Emission CT (SPECT), or Positron Emission Tomography (PET), into one single 3D data set. To this purpose, real time transformation algorithms and presentation techniques will be designed in the third sub-project. The three challenges are to visualise the tissue behind the organ surface by use of augmented reality for the surgeon to avoid critical structures like vessels, nerves and tumours; to enable steering of the surgical tools in catheterisation procedures, using x-ray, MRI or ultrasound, based on physiological signals; and to manipulate diagnostic information components in their mutual spatial relation.

The minimally invasive surgeon still has to work with surgical instruments of insufficient quality due to a limited freedom of movement and high degree of friction that eliminates the tactile feedback. The fourth sub-project in MISIT deals with the design of suitable tools for suturing, performing anastomoses or blood vessel connections, gripping of soft tissue, and orthopaedic surgery. The new tools will be quantitatively tested in a simulator environment and, if success is proven, prototypes will be developed to be clinically evaluated in the operating theatre. The fifth sub-project will develop prototype catheters with reduced diameter and optimised mechanical properties for a controlled steerability to be used in new clinical procedures.

The reduction of the catheter diameters has direct implications for the size of both actuators and sensors that are placed at the catheter tip to monitor the internal state of the patient by measuring physical quantities like pressures, temperatures, voltages, and ultrasound reflections or to visualise inner body structures. Researchers in the sixth sub-project will develop miniaturisation methods for sensors and actuators, as well as implement innovative interface techniques. The new protocols, instruments and technologies which are to be designed for minimally invasive surgery, will be evaluated in a broad range of medical specialities including cardiology, gynaecology, orthopaedics, urology, anaesthesiology, and interventional radiology. More detailed information on the project is available at the MISIT Web site.


Leslie Versweyveld

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