Development of steerable instruments for minimal invasive surgery in modular conception.

The augmenting complexity of minimal invasive interventions requests a continuous improvement of technologies. Extended endoscopic procedures, e.g. laparoscopic-transanal sigmoidectomy or thoracoscopic esophagus dissection require difficult surgical manipulations like mobilisation, sceletonization as well as ligatures and sutures. They are difficult to perform with the present endo-surgical instruments. A major instrumental weakness is represented by the restricted steerability because of the rigid shaft axis and the resulting low degrees of freedom (DOF). Therefore a series of steerable flexible instruments has been developed in interdisciplinary cooperation between surgeons and engineers. The prototypes provide a multi-joint working as the instrument's elbow, which allows to incline the tip around +/- 280 degrees. The second additional DOF is the rotation of the surgical tool. The prototypes have been experimentally tested in laparoscopy and thoracoscopy, showing a clear improvement in the carrying out of complex operative manipulations. The further development is performed in modular conception, including electric drives.