Page 413 - Flexible Robotics in Medicine

EndoGoose: a flexible and steerable endoscopic forceps 407

Regarding the materials used for the prototype, the connected beads and springs and
gooseneck tubes are to be manufactured with medical-grade austenitic stainless steel as it
provides excellent mechanical properties, high corrosion resistance, and east formability.
The forceps can be manufactured with alloys (Table 18.1) due to the excellent wear and
corrosion resistance and good fatigue strength. Assembling the forceps and the bending
segment, the distal end is shown in Fig. 18.3.

The biopsy forceps jaw assembly comprising of rectangular cupped opposed similar jaws,
each jaw having a plurality of teeth around the sides, and a sharpened front edge with the
shape of a pyramid. The jaws close when the distal end of actuating means is pulled by the
operator. The jaws are connected to the front joint of the flexible main body and to each
other by a hinge, with a spring in a perpendicular direction with respect to the hinge, fitted
through depressions in the forceps end and connected to each jaw. Forceps with alligator
jaws along the side edges have a sharp front edge that mimics the jaws of a nail-clipper.
The forceps jaws are symmetrical, supported by a hinge and a spring in between its ends to
keep it open. The current prototype allowed the operator to steer the forceps in the direction
of the tissue, giving more range of motion. The motor connected to the forceps makes the
prototype more straightforward to use, as one can control the direction of movement via a
joystick. Furthermore, with the flexible spine being able to stay in place after bending to the
desired angle, there is no need to continue holding on to the joystick while opening and
closing the forceps to perform the biopsy. The essential part of EndoGoose is the distal
biopsy portion, with razors acting as clippers. This is meant to cut through the tissue to ease
the withdrawal of the tissue because the biopsy sample has been cut out of the whole tissue,
as compared to the current method of just grasping a portion of the tissue and pulling it out
without first cutting the small portion.

18.2.3 Control box

At the proximal end, there is a control box for endoscope tool manipulation, as shown in
Fig. 18.4. It houses the stepper motors used to provide the torque needed to steer the
bending segment. An Arduino Uno programs the way the stepper motor will turn in order to
steer the bending segment. On top of the control box, the joystick is mounted, as well as a
knob to close the forceps. Forceps is in a default open mode, and it is held open by a
spring. The stepper motor is controlled by a joystick and then wired for the forceps to
bend in the direction of the joystick turning. The control box also holds the batteries to
power the system. The actively bending section can be controlled using a joystick that is
present on the control box. The forceps can be opened and closed via a slider present on
the control box. The forceps is open by default, and pulling the slider will close the forceps,
to grab the tissue. The EndoGoose also requires a power source of 12 V to operate most
effectively.