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Unlike
historical surgical techniques, endoscopic surgery exploits
smaller tools that are manipulated from outside the patient.
Since the surgeon's hands aren't inside the patient, you
don't need a large opening into the body. A small tube
that is "snaked" into place delivers the tiny surgical
tools to the site of the surgery. But this type of surgery
provides some real challenges in orientation. Much like
sailors using a tiller to steer a sailboat, a surgeon
must learn how to manipulate these devices within the
body cavity "backwards," and therefore in an unfamiliar
way. As you saw in the segment "Robot
Heart Surgeon" , some recent improvements in
this technology now offer surgeons the richness of three-dimensional
views, along with images that help maintain the right/left
orientation of the subject.
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OBJECTIVE
This activity page will offer:
- A
lab experience during which students construct a basic electric
circuit and use it to explore dexterity skills
- A
chance to construct and operate a tool that extends a person's
grasping ability and to model endoscopic surgery
- An
opportunity to design and create an improved remote tool
MATERIALS
-
Bell or light circuit (light, wire, cell (a.k.a. battery),
and cell holder)
- Aluminum
foil
- Inexpensive
metal tweezers
- modeling
clay
- scissors
- heavy
stock paper
- brass
fasteners
- hole
punch
- tape
- bell
wire (insulation removed from ends)
- packing
cardboard
Part
1- Constructing The Challenge
PROCEDURE
-
Work with a partner. Assemble a circuit using copper insulated
wire, a lamp or bell, battery holder and appropriate cell.
Test the circuit to make sure that all components are functional.
Once this basic circuit has been tested, it's ready to be
used in creating an "operation" game.
-
Soften a small lump of clay. Use your fingers to shape a
well that is slightly larger than a metal paper clip. This
depression should be about 1 centimeter deep and be just
large enough to accept a paperclip.
-
Line the walls of this depression with a strip of aluminum
foil. The floor of the depression should remain free of
any foil.
- Disassemble
one of the circuit wires. Attach this exposed lead to the
aluminum foil. Use the other wire to connect the open part
of the circuit to metal tweezers as shown in the diagram
below.
- Test
your circuit by touching the tweezers to the foil. The light/bell
should operate.
-
Position the clip in the center of the depression. Make
sure that it does not touch any foil.
- Challenge
your partner to remove the paper clip without touching the
sides of the cavity. Once each of you has perfected the
technique, move on to the endoscopic challenge.
PART
2 - Building A Remote Manipulator
- Work
with a partner. Cut out four strips of heavy stock paper.
Each strip should be about 15 centimeters long and 2 centimeters
wide.
-
Use a hole punch to place two holes in each strip. One hole
should be positioned in the center of the strip. The other
hole should be positioned about 2 cm from the edge as shown
here in the diagram.
-
Assemble the expandable arm as shown here. Use brass fasteners
to secure the joints at which movement occurs.
- Straighten
two paper clips. Attach one clip to each of the two ends
of the manipulator. Use tape to secure the clips. Open and
close the arm. Place a small bend in each clip so the tips
of these metal extensions meet when the arm is extended.
-
Detach the tweezers from the bell circuit. Attach this free
wire to either of the two paper clips. Test the bell circuit
by touching the "hot clip" to the aluminum foil wall. If
the bell does not sound, recheck the connections.
PART
3- The Challenges Of Endoscopic Surgery
- Cut
a 7-centimeter diameter hole in the center of a sheet of
packing cardboard.
- Insert
this sheet into a lump of clay and position it upright in
front of the operating stage as shown below.
- Challenge
the "surgeon" to remove the clip without sounding the bell.
Although the tool must be manipulated through the hole,
the surgeon is allowed any view to observe the action of
the tool, such as over the top or around the sides of the
screen.
- Once
you have finished your endoscopic challenge, exchange roles
with your partner so that you each have the opportunity
to experience this model of remote surgery.
Analyze
Your Model
Compare
and contrast this classroom experience with endoscopic surgery.
How is it similar? How is it different? How might you better
model the surgeons limited view of the operation? Can you
design a more realistic surgery using other materials?
Build
A Better Manipulator
Can
you improve the design of this manipulator? If so, how? What
changes would increase the dexterity of the grabber? Make
a sketch of your improved device. With you instructor's approval
build your endoscopic tool. Test your tool against devices
created by classmates.
Web
Connection
Medical
Robotics
See various manipulator tools that perform endoscopic surgery.
Yale
University School of Medicine Heart Book
An incredibly rich and extensive site from Yale University
on all aspects of the heart and heart disease. of risk factors
associated with heart disease.
The
activities in this guide were contributed by Michael DiSpezio,
a Massachusetts-based science writer and author of "Critical
Thinking Puzzles" and "Awesome Experiments in Light & Sound"
(Sterling Publishing Co., NY).
Academic
Advisors for this guide
Corrine Lowen, Science Department, Wayland Public Schools,
Wayland, MA
Suzanne Panico, Science Department, Fenway High School, Boston,
MA
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