Page 118 - Flexible Robotics in Medicine

104 Chapter 5

intubation scopes used during PT procedures for better visualization. These endoscopes
are usually flexible and can bend freely to about 180 degrees upward and downward.
The insertion diameter of the endoscopes varies. The diameter of the Olympus LF TP
is 5.2 mm, that of the Ambu aScope 4 Broncho Slim varies from 3.8 to 4.3 mm, and
that of the Pentax FI-7RBS is 2.4 mm. The working length of these endoscopes is
60 mm, as they are often used as bronchoscopes. While the Olympus LF TP and the
Pentax FI-7RBS are controlled manually and can be used repeatedly after sterilization,
the Ambu aScope 4 Broncho Slim is controlled using a controlled lever, and its insertion
tube is designed for one-time use only. This feature is an advantage since the
endoscopist can view the real-time image and control the endoscope simultaneously and
in a shorter period. Inserting an endoscope into the body is tedious as the endoscopist
needs to have a firm hand while inserting the fiberscope slowly.
We have used these devices as references to the modular origami joint operator (MOJO),
which has increased stability and can perform a minimally invasive tracheostomy
procedure. MOJO utilizes controlled forces and a manual actuation mechanism to provide
stability to the device. The tracheostomy technique and device shall be able to reduce the
complications of PT, apply a controlled force to the needle, and provide stability and
guidance for needle puncture through the tissue.

5.1.4 Summary of prior art in endoscopic manipulators

Tracheostomies are required in cases such as when there is a need for extended
intubation, a need for facilitation of ventilation, excess secretions by the lungs, or
airway obstruction. This process is a form of surgery usually performed using surgical
tools such as scalpels. In the case of OT, blunt dissection is performed below the second
tracheal ring, and in the case of PT, an incision is made using a scalpel and further
dilated by a bronchoscope. Current bronchoscopes and devices purposed for endoscopic
surgery consist of long cables and tubes with a controllable distal tip. Endoscopes have
progressed from being used in diagnostic and imaging operations to interventional
operations such as biopsies.

The curvilinear steering property of the MOJO’s design can be applied to accommodate
other tools such as cauterizers, electrosurgical excision loops, and other surgical tools
required to navigate complex paths in MIS.

Endoscopic manipulators such as tubular continuums, microactuators, shape memory alloys,
and remotely actuated hinge joints are examples of techniques used to provide mobilities as
well as constraints to limit the degree of freedom (DOF) of steerable sections [8]. For the
purpose of the MOJO device, we will be focusing on the method of providing mobility and
stability to endoscopes rather than a method of actuation. One study outlines the design of
flexible hinge joints for steerable medical devices [9].