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Bioloch studies performed in phase 1 of the
project
Marc O. Schurr, Daniel Kalanovic
Section for Minimally Invasive Surgery, University
of Tübingen
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Applicational force pattern measurement overview
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Mesenteric hazards of endoscopic BIOLOCH devices
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Colonic wall hazards of endoscopic BIOLOCH
devices
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Force pattern for walking devices
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Force pattern for creeping devices
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Applicational force pattern measurement overview
2
Mesenteric hazards of endoscopic BIOLOCH devices
3
Colonic wall hazards of endoscopic BIOLOCH
devices
4
Force pattern for walking devices
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Force pattern for creeping devices
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Description of force parameters of the colonic
tract in interaction with endoscopic devices and
techniques
Different experimental series have been performed
to describe the interaction of ttols and bowel.

• Parameters for
• walking inside
• the colon
• Forces
• Wall elasiticity

• Mesenteric hazards
• Tears
• Ruptures

Force pattern overview
Mesenteric resistance
Force / step ratio
Colonic wall resistance
Device advancement forces

• Paremeters for
• creeping inside
• the colon
• With tail
• Without tail

• Colonic hazards
• Perforation

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1
Applicational force pattern measurement overview
2
Mesenteric hazards of endoscopic BIOLOCH devices
3
Colonic wall hazards of endoscopic BIOLOCH
devices
4
Force pattern for walking devices
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Force pattern for creeping devices
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Mesenteric hazards.
Forces resulting in mesenteric tears or
perforation of the colon were studied.
Mesenteric damage
Bowel perforation
Force measurement gauge
Pushing against the bowel wall
Pulling on the mesentery
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Determination of threshold forces causing damage
to bowel and mesentery
Mesenteric lesions can be caused by excessive
radial forces exerted on the bowel holding
apparatus.
Formation of mesenteric tears as a result of
radial forces
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1
Applicational force pattern measurement overview
2
Mesenteric hazards of endoscopic BIOLOCH devices
3
Colonic wall hazards of endoscopic BIOLOCH
devices
4
Force pattern for walking devices
5
Force pattern for creeping devices
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Colonic wall hazards.
Depending on their size, components of an
endoscopic device can perforate the colonic
wall at relatively low forces. This implies, that
precaution has to be taken in all self-locomoting
mechanisms.
Perforation of colonic wall as a result of
perpendicular device collision
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1
Applicational force pattern measurement overview
2
Mesenteric hazards of endoscopic BIOLOCH devices
3
Colonic wall hazards of endoscopic BIOLOCH
devices
4
Force pattern for walking devices
5
Force pattern for creeping devices
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Force pattern for walking mechanisms.
In the measurements the force / step relationship
was determined in context with bowel
tissue elasticity .
At what force does a step of an imaginary walking
instrument get ineffective ?
Bowel wall displacement
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Force pattern for walking mechanisms.
In the first series of experiments, only the
mucosal layer was grasped (grasping leg).
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Force pattern for walking mechanisms.
With mucosal attachment, grasping legs seem not
to be able to transport sufficient loads (device
weight and friction).
Force / Step ratio, grasping leg, mucosal
attachment
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Force pattern for walking mechanisms.
In the second series of experiments, also the
muscular layer was grasped (grasping leg).
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Force pattern for walking mechanisms.
With muscular attachment, grasping legs can
transport multiples of the loads compared to
mucosal attachment.
Force / Step ratio, grasping leg, muscular
attachment
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Force pattern for walking mechanisms.
In the third series of experiments, mucosal
suction (suction leg) was used.
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Force pattern for walking mechanisms.
Suction legs did not yield more holding
capabilites than mucosal grasping.
Force / Step ratio, suction leg, mucosal
attachment
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Force pattern for walking mechanisms.
In comparison the value of mucosal involvement
into the locomotion process get clear.
Force / Step ratio, comparison
1. 1 cm 2. 1.5 cm 3. 2 cm 4. 2.5 cm
average values of 10 experiments
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1
Applicational force pattern measurement overview
2
Mesenteric hazards of endoscopic BIOLOCH devices
3
Colonic wall hazards of endoscopic BIOLOCH
devices
4
Force pattern for walking devices
5
Force pattern for creeping devices
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Force pattern for creeping mechanisms.
A dummy of a creeping mechanism (20 X 80 mm, 100
g) was used to study the forces involved for
passage of the different segments of the colon.
Set-up with animal tissue
Device dummy head pulled through the bowel
Two version with and without tail
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Forces related to the passage of a 20x80 mm
device through the colon
Measurement results help to understand the
bowel-device interaction better.
Comparison 20 x 80 mm device with and without
tail
1. Anus 2. Rectum 3. Sigmoid 4. Descending
colon 5. Transverse colon 6. Ascending colon
average values of 20 experiments
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Forces related to the passage of a 20x80 mm
device through the colon
Measurement results help to understand the
bowel-device interaction better.
20 x 80 mm device pulled through the large bowel
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Forces related to the passage of a 20x80 mm
device through the colon
Measurement results help to understand the
bowel-device interaction better.
20 x 80 mm device with tail pulled through the
large bowel
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Conclusions
Initial conclusions to be drawn from the
applicational force measurements.
1. Hazards for the colon wall and the mesentery
start at 3 - 6 N, respectively, depending on the
size of the device. 2. To overcome the basic
problem of inch-worm creeping devices, speed,
walking may be an option. The mechanical
restistance of the colonic wall allows to apply
forces of about 1 N to at ground displacement of
2 cm, provided, that the muscular layer is
involved. 3. Mechanisms, that only involve the
mucosal layer may be less effective. 4. The
pulling force required to move a creeping dummy
object through the colon can come up to 8 N. A
tail may easily double the force required to
move the object.
Clearance of the colonic wall to minimize
friction.
Walking legs for locomotion.