Page 482 - Flexible Robotics in Medicine

476 Chapter 21

curvature of the distal end is controlled by a lever located at the proximal end of the
flexible endoscopic manipulator. By rotating the lever forward and backward, the distal end
of the endoscopic manipulator curves downward and upward, respectively. However, the
curvature of the distal end is only in a single plane, granting the flexible endoscopic
manipulator only one degree of freedom (DOF). Curvature along a single plane reduces
maneuverability because the operator will need to rotate the entire endoscopic manipulator
to achieve curvature along a different plane, thereby causing the endoscopic manipulator
body to rotate about its primary axis. The rotation of the entire endoscopic manipulator will
cause more significant discomfort to the patient, as the entire working length of the
endoscopic manipulator, which is in contact with the patient’s nasal cavity, will also rotate
and rub against the nasal cavity. Rotation will also result in the operator having to dorsiflex
or palmar flex his/her wrists. The awkward positioning may make the procedure more
difficult for the operator, thereby increasing the risk of error and damage to healthy tissue.
The collection of biopsy samples also requires the assistance of a nurse because the
operator requires both hands to support and manipulate the flexible endoscopic manipulator.
The nurse is needed to insert the forceps tool through the instrument channel and operate
the opening and closing of the forceps jaws to collect the sample. The nurse relies mainly
on the operator’s verbal commands, as he/she is the one who has spatial awareness of the
nasopharynx as he/she views through the camera. Therefore miscommunication and
disorientation are possible causes of error.
The forceps tool through the instruments channel is usually a passive flexible tool. The tool
bends according to the curvature of the flexible endoscopic manipulator. Because of its
compliant nature, the forceps rely on the endoscopic manipulator for support. Overextension
of the forceps too far beyond the distal orifice of the endoscopic manipulator will subject
the forceps to external forces and prevent the effective use of the forceps. Therefore the
forceps are limited by their compliant nature, and the operator has to bring the end of the
endoscopic manipulator very close to the target tissue for the forceps to work effectively.
Doing so affects the range of view of the camera.

21.1.4 The objective of the present study

The concern and challenges in the diagnosis of NPC motivate this flexible endoscopic
manipulator with a biopsy forceps for in vivo procedures. The features of OmniFlex include
(1) ease and convenient usage; (2) purely mechanical, simple, and intuitive control; (3)
lightweight and portable. In addition to NPC, there is also a pronounced need for regular
monitoring and feedback of tumor progression and characterization based on mechanical
pliability, stiffness, and elasticity [18 20]. With the shortcomings of current endoscopic
manipulators in mind, OmniFlex’s unique features will improve patients with NPC and the
operators, in specific, the ENT specialists.