Page 397 - Flexible Robotics in Medicine

390 Chapter 17

requires incisions through the skin. Therefore it is still relatively more invasive of a process
as compared to performing the natural orifice transluminal endoscopic surgery (NOTES)
with a robotic endoscopic surgical system, which only requires insertion through a natural
orifice such as a mouth, with no incisions for entry [1].
The current surgical instruments for NOTES [2,3] are operated by surgeons directly, which
requires high-level surgical skills as the natural orifice is long and narrow. The endoscopy
system has been a reliable mode of minimally invasive instrument [4] that are easily accessible.

Conventional endoscopy systems have limited accessibility to target tissue that is inhabited
in the flexure of the colon, as in the case of endoscopic submucosal dissection (ESD)
procedure [4]. This limitation is attributed to the substantial stiffness constant possessed
by conventional endoscopic manipulators, thus resulting in a limited bending angle of the
manipulators. Therefore the manipulators are unable to access target tissues in a confined
surgical space [5].

Furthermore, conventional endoscopy systems exhibit a lack of a multitasking manipulator
platform, whereby only a single instrument (i.e., forceps or snare tool) can be inserted one
at a time into the gastrointestinal (GI) tract, resulting in time-consuming manual swapping
of devices. Moreover, repeated removal and insertion of the endoscope increase rates of
perforation and bleeding.

A robotic endoscopy system performs the main functions of a conventional endoscopy
system, such as to visualize the interior of the GI tract to expose target tissue. Additionally, it
can remove the target tissue through natural orifices such as the oral or anal cavity, depending
on the locality of the tissue. A distinguishing factor that sets the robotic endoscopy system
apart from the conventional endoscopy system is the master-slave configuration. A surgeon
controls the master unit such that this would translate into the corresponding movement of the
endoscopic instruments in the slave unit, as opposed to directly controlling the movements of
the endoscope in the case of the conventional system [2].
During the NOTES operation, sufficient stiffness of the manipulator is ideal for adequate
accuracy, while low-stiffness compliance is also necessary for the safety consideration [6].
It is useful for surgical robots with both rigidness and compliance to address the above
issues [7 9]. For the operation in a narrow space with a limited field of view, a positioning
accuracy in the submillimeter level is usually necessary [10]. The workspace of the surgical
robotics depends on the specific environment of the NOTES, which should cover the range
of the target area. The surgical robotics should avoid secondary injury to the human body
when being manipulated. Collision avoidance among the arms of the devices, compliant
mechanisms, and the stable system has the benefits to increase the level of safety [11].
The standard medical process, such as pasteurization, can be conducted if the materials of
the surgical robotics support this method. Alternatively, surgical robots can be covered by