Haptic feedback in minamally invasive surgery

developed at KULeuven, Belgium

Minimally invasive surgery or endoscopy (laparoscopy (abdominal surgery), arthroscopy (orthopaedic surgery) and thoracoscopy (lung surgery)), is revolutionising the surgical practice. It enables access to internal anatomy via small incisions or orifices, minimising trauma to surrounding tissue and reducing recovery time, risk and costs. However, surgeons find it difficult to manually perform procedures that require dexterity and fine motion capability with minimally invasive techniques. Remotely controlled robotic manipulators are therefore being developed to increase dexterity and accuracy. These systems have some distinct drawbacks, such as: (i) lack of local manipulability of the tools, (ii) the absence of force and tactile feedback to the surgeon's hands and (iii) lack of a natural interface with the surgeon. It would be useful if the surgeon would have the same freedom to acquire information as he/she has in open surgery. By rubbing and palpating the tissue he/she gets information on texture and structure of the tissue, on blood stream pulsations through arteries, etc. The aim of this project is to restoring this kind of feeling during the robotic surgery (figure 1).

Figure 1

A teletactile system consists of three basic elements: (i) a tactile sensor, to remotely collect raw tactile data, (ii) a tactile-data processing system, and (iii) a 'tactile display', presenting the tactile information in a natural and realistic way to the surgeon. A telesurgical system with reliable force feedback can extend the application range of minimally invasive surgery to more complex procedures. For medical decisions that are primarily based on touch information, such as the localisation of a tumour or hidden arteries or the quality verification of a suture, surgeons mainly rely on their stiffness perception and discrimination abilities.

Figure 2 - click figure for movie.

An alternative way to develop a tactile sensor is to use the elastography. Elastography is a method that can ultimately generate a new kind of image called elastograms. These images have the caracteristic of been based on the stiffness of the organs. This is a new powerful way of diagnosis, for example a tumour will have a different stiffness of the surrounding tissue, this property can be easily identify with the elastography. This new idea can be applied also to the haptic feedback, a sensor based on elastography can record information on the stiffness of tissues and give to the surgeon these information in a "tactile way". A system was developed for the calculation of the stiffness of some volumes when the elastogram is given. The system was tested on four different phantoms with four different stiffnesses, these first experiments had shown a very good behaviour when used on homogeneus volumes. The next steps of the work will be the developing of a new sensor; this will be able to reconstruct the stiffness of a non homogeneous volume. Finally all the system will be implemented and tested on a real laparoscopic application (figure 2).

A work on Kinaesthetic feedback and enhanced sensitivity in robotic endoscopic telesurgery was done.This system restore the kynaestetic force feeling that is lost with the modern Surgeon Robots (e.g. how much the surgeon is pulling a tissue), this can leads to evident problems during the surgery, like the tissue damaging. The aim of this new system is to restore this feeling in the Robotic Laparoscopic Surgery (figure 2).

Figure 3

In collaboration with the Oslo partner a new robotic tool was built. Small tumour like prostate cancer, liver cancer and other tumours of the deep organs can be treated using the radio frequency ablation. This technique consists in a minimally invasive approach to the tumour healing. Using a long needle the surgeon reach the tumoural mass and injecting electrical current literally "burns" the tissue. From the literature was seen that a rotation performed during the insertion of the needle reduces the deformation of the tissues and organs. Here the idea of apply a rotation while inserting the needle was borne. From the collaboration between KuLeuven, Belgium and Interventional centre Oslo, Norway, the tool was designed and built (figure 3).

Kinematic demo