InitRech 2015/2016, sujet 8

Summary

With the aim of training new surgeon-students, HAL proposes a computer-based training system for cataract surgery in this paper. Indeed, this operation, to be well done, needs a lot of practice. However, sutends can't train themselves with real patients. Moreover, this training system allows students to make some mistakes and keep training, which is not the case in reality.

The system described is thought to be as realistic as possible, for instance there is a 3D mannequin to realize operations, a full environment which looks like a true surgery room (with mmonitors, surgery tools, ...). This training system is based on a software: SOFA. In this, all is calculated and close to the reality: real values are used to configure the tools, the deformation of the capsule or the lens isn't random but genuine.

Firstly, the deformation of the lens is represented thanks to a co-rotational FEM (Finite element models) formulation with linear elasticity and tetrahedral mesh tessellated in order to produce small elements. With this method, all the calculations aren't done so it dosen't need a lot of time to change the topology of this mesh, that's why it's interessant. Moreover, the surgeon-student can use the phacoemulsifier in two different ways: Aspiration or Fragmentation. The aspiration is used to move liquids from the eye to the tip whereas fragmentation breaks the lens due to the tip's vibrations. During an operation, the quantity of light that is bouncing back from the retina through the lens is a really important signal for the surgeon, this effect can be reproduced thanks to 'Projected Tetrahedra'.

Secondly, they focused on Continuous curvilinear capsulorhexis, which its main aim is to create a perfect opening avoiding some tear during the surgery.To model the deformation and tearing of thin soft tissue, a transversely isotropic elastic model is used. Thanks to this model, the direction of tear's propragation can be known.

mesh=grillage/réseau coarse=épais tip=bout cue=signal shaders=ombreurs? tessellated=mosaïque

Main contribution

This article's main aim is to introduce us a Computer-based training system in the field of surgery. More precisely, the main contribution of this project is to help new surgeons for the cataract surgery. This project is really usefull and interesting because the students can train themselves with a very realistic environment and a 3D mannequin. The cataract surgery is more difficult than other some operations and thanks to this project, the new profesionnals can make some mistakes, fail, but they can do this simulation again and again in order to improve their skills. We all know that a simulation isn't the reality and that all hazards can't be reproduced with this training but it can be usefull for the student, in my opinion, to practice himself before doing a real operation with real risks at the first error. In this project, everything is taken into account in order to make this system of training as close of the reality as possible, that's why after exercising with this simulator, the students will be able to do a real surgery without significant changes except exceptional situations.