Preliminary User Studies of A Virtual Reality Medical Training System for Bone
Drilling Procedures
Hasan Esen, Ken’ichi Yano, Martin Buss
 Institute of Automatic Control Engineering, Technische Universit¨at M¨unchen,
Munich, Germany, Emails: hasan.esen@ei.tum.de, mb@tum.de
 Department of Mechanical and Systems Engineering, Gifu University,
Gifu, Japan, Email: yano-k@cc.gifu-u.ac.jp
Abstract— In this work, a prototype medical training system
(MTS) for teaching bone drilling is proposed. The MTS
contains 3D graphical and 3D haptic displays. For teaching
purposes, a control algorithm is developed and presented.
Results of preliminary user tests suggest that proposed
medical training system is a powerful tool for training core
skills of a bone drilling procedure.
I. INTRODUCTION
Classical surgery training methods, such as observing
an expert surgeon, experiments on cadavers or animals
have some weaknesses. For example observations do not
provide with the haptic feeling of the surgery, whereas
cadaver or animal experiments introduce ethical problems
and they are not realistic enough in many cases. Therefore
developing alternative training methods in a virtual
environment (VE) has become a challenging research area
recently.
Although there are several works on developing simulators
for minimally invasive surgery (MIS) [1]–[4], there are
rather few works concerning surgery for cutting, burring,
and drilling of bones. Most of the works in the area of
bone surgery simulation deal with reading and transferring
the real surgery data and haptic rendering algorithms.
Schmidt concentrates on visualization of vertebrae drilling
surgery using real CT data [5]. The work of Zorcolo et al.
deals with bone dissection and burr cleaning simulation
problems [6], whereas Luewer et al. underlines the
importance of multi-point based collision detection and
volume based modeling for the bone petrous surgery [7].
Some other works discussing important parameters for
drilling into bone are [8]–[10].
Taking into account that bone drilling is needed prior
to many orthopedical operations and it requires a high
surgeon skill, this work is directed to develop a virtual
reality (VR) medical training system (MTS) that helps
novice surgeon and medical students in training the core
skills of a bone drilling operation. These core skills
are: Recognizing drilling end - point; applying constant,
sufficient but non-excessive thrust force and feeding
velocity. Bone drilling forces are investigated by Udiljak
et al. and they emphasized that the necessary force to drill
into a bone may be as large as 220 N [10]. Especially
learning to apply large forces appropriately is crucial for
novice surgeons. Therefore in this project, it is aimed to
teach as large forces as the used hardware allows. The
developed MTS comprises a 3 DOF haptic display and
two different graphical user interfaces (GUIs) which are
discussed in section II and III respectively. The system
improved by adding acoustic feedback that is discussed in
section IV. The novel controller algorithm developed by
Esen et al. for teaching bone drilling with 1 DOF haptic
feedback, is improved for 3 DOF haptic feedback and
presented in section V. The concept of the training system
can be seen in figure 1.
Several user tests are performed to check the developed
MTS whether it helps improving the bone drilling skill of
the users or not. For this work, haptic, visual, and acoustic
feedbacks are all in use during user tests, whereas in
previous works acoustic feedback was not available [11].
Visual and Acoustic  
Feedback
Haptic Feedback
Fig. 1. Concept of the bone drilling medical training system
II. HAPTIC DEVICE: VISHARD3
The haptic device VISHARD3 has been developed at
Technical University of Berlin, while all authors were in
Berlin [12]. As it is seen in figures 1 and 2, it has 3
active DOF, but there is a possibility to add 3 more passive
DOF by an end-effector design. Preliminary user tests are
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