1 Department for Pediatric Surgery, Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands; Technical Medicine, Faculty of Science and Technology, University of Twente, Enschede, the Netherlands.
2 Department for Pediatric Surgery, Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands.
3 Robotics and Mechatronics, University of Twente, Enschede, the Netherlands.
4 Department for Pediatric Surgery, Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands. Electronic address: A.F.W.vanderSteeg@prinsesmaximacentrum.nl.