Flexible endoscopes are used for diagnostic and therapeutic interventions in the human body for their ability to be advanced through tortuous trajectories. However, this very same property causes difficulties as well. For example, during surgery, a rigid shaft would be more beneficial since it provides more stability and it allows for better surgical accuracy. In order to keep the flexibility and to obtain the rigidity when needed, a shaft-guide with controllable rigidity could be used. In this article, we introduce the plastolock shaft-guide concept, which uses thermoplastics that are reversibly switched from rigid to compliant by changing their temperatures from 5°C to 43°C. These materials are used to make a shaft that can be rendered flexible to follow the flexible endoscope and rigid to guide it. To find polymers that are suitable for the plastolock concept, an extensive database and internet search was performed. The results suggest that many suitable materials are available or can be custom synthesized to meet the requirements. The thermoplastic polymer Purasorb® PLC 7015 was obtained and a dynamic mechanical analysis showed that it is suitable for the plastolock concept. A simple production test indicated that this material is suitable for prototyping by molding. Overall, the results in this article show that the plastolock concept can offer simple, scalable solutions for medical situations that desire stiffness at one instance and flexibility at another.

1.
Baillie
,
J.
, 2007, “
The Endoscope
,”
Gastrointest. Endosc.
0016-5107,
65
(
6
), pp.
886
893
.
2.
Church
,
J. M.
, 1993, “
Ancillary Colonoscope Insertion Techniques—An Evaluation
,”
Surg. Endosc.
,
7
(
3
), pp.
191
193
.
3.
Cotton
,
P. B.
,
Williams
,
C. B.
,
Hawes
,
R. H.
, and
Saunders
,
B. P.
, 2009,
Practical Gastrointestinal Endoscopy: The Fundamentals
,
6th ed.
,
Wiley-Blackwell
,
Chichester, UK
.
4.
Hawes
,
R. H.
,
Rattner
,
D. W.
,
Fleischer
,
D.
,
Gostout
,
C. J.
,
Kalloo
,
A.
,
Kochman
,
M.
,
Marohn
,
M.
,
Ponsky
,
J.
,
Rothstein
,
R.
,
Schwaitzberg
,
S.
,
Smith
,
C. D.
,
Swantsrom
,
L.
,
Talamini
,
M.
, and
Thompson
,
C. C.
, 2008, “
Notes : Where Have We Been and Where Are We Going?
,”
Gastrointest. Endosc.
0016-5107,
67
(
6
), pp.
779
780
.
5.
Hull
,
T.
, and
Church
,
J. M.
, 1994, “
Colonoscopy—How Difficult, How Painful?
,”
Surg. Endosc.
,
8
(
7
), pp.
784
787
.
6.
Lee
,
S. -H.
,
Chung
,
I. -K.
,
Kim
,
S. -J.
,
Ko
,
B. -M.
,
Hwangbo
,
Y.
,
Kim
,
W. H.
,
Park
,
D. H.
,
Lee
,
S. K.
,
Park
,
C. H.
,
Baek
,
I. -H.
,
Park
,
D. I.
,
Park
,
S. -J.
,
Ji
,
J. -S.
,
Jang
,
B. -I.
,
Jeen
,
Y. -T.
,
Sheen
,
J. E.
,
Byeon
,
J. -S.
,
Eun
,
C. -S.
, and
Han
,
D. S.
, 2008, “
An Adequate Level of Training for Technical Competence in Screening and Diagnostic Colonoscopy: A Prospective Multicenter Evaluation of the Learning Curve
,”
Gastrointest. Endosc.
0016-5107,
67
(
4
), pp.
683
689
.
7.
Leung
,
F. W.
, 2008, “
Methods of Reducing Discomfort During Colonoscopy
,”
Dig. Dis. Sci.
0163-2116,
53
(
6
), pp.
1462
1467
.
8.
Rattner
,
D.
, and
Kalloo
,
A.
, 2006, “
Asge/Sages Working Group on Natural Orifice Translumenal Endoscopic Surgery: October 2005
,”
Surg. Endosc.
,
20
(
2
), pp.
329
333
.
9.
Shah
,
S. G.
,
Saunders
,
B. P.
,
Brooker
,
J. C.
, and
Williams
,
C. B.
, 2000, “
Magnetic Imaging of Colonoscopy: An Audit of Looping, Accuracy and Ancillary Maneuvers
,”
Gastrointest. Endosc.
0016-5107,
52
(
1
), pp.
1
8
.
10.
Shih
,
S. P.
,
Kantsevoy
,
S. V.
,
Kalloo
,
A. N.
,
Magno
,
P.
,
Giday
,
S. A.
,
Ko
,
C. –W.
,
Isakovich
,
N. V.
,
Meireles
,
O.
,
Hanly
,
E. J.
, and
Marohn
,
M. R.
, 2007, “
Hybrid Minimally Invasive Surgery—A Bridge Between Laparoscopic and Translumenal Surgery
,”
Surg. Endosc.
,
21
(
8
), pp.
1450
1453
.
11.
Wehrmeyer
,
J. A.
,
Barthel
,
J. A.
,
Roth
,
J. P.
, and
Saifuddin
,
T.
, 1998, “
Colonoscope Flexural Rigidity Measurement
,”
Med. Biol. Eng. Comput.
0140-0118,
36
(
4
), pp.
475
479
.
12.
Brooker
,
J. C.
,
Saunders
,
B. P.
,
Shah
,
S. G.
, and
Williams
,
C. B.
, 2000, “
A New Variable Stiffness Colonoscope Makes Colonoscopy Easier: A Randomised Controlled Trial
,”
Gut
0017-5749,
46
(
6
), pp.
801
805
.
13.
Rex
,
D. K.
,
Khashab
,
M.
,
Raju
,
G. S.
,
Pasricha
,
J.
, and
Kozarek
,
R.
, 2005, “
Insertability and Safety of a Shape-Locking Device for Colonoscopy
,”
Am. J. Gastroenterol.
0002-9270,
100
(
4
), pp.
817
820
.
14.
Swanstrom
,
L. L.
,
Kozarek
,
R.
,
Pasricha
,
P. J.
,
Gross
,
S.
,
Birkett
,
D.
,
Park
,
P. -O.
,
Saadat
,
V.
,
Ewers
,
R.
, and
Swain
,
P.
, 2005, “
Development of a New Access Device for Transgastric Surgery
,”
J. Gastrointest Surg.
1091-255X,
9
(
8
), pp.
1129
1137
.
15.
Saadat
,
V.
,
Rothe
,
C. A.
,
Ewers
,
R. C.
,
Maahs
,
T. D.
, and
Michlitsch
,
K. J.
, 2006, “
Endoluminal Tool Deployment System
,” U.S. Patent No. 2006/0178560.
16.
Ota
,
T.
,
Degani
,
A.
,
Schwartzman
,
D.
,
Zubiate
,
B.
,
McGravey
,
J.
,
Choset
,
H.
, and
Zenati
,
M. A.
, 2009, “
A Highly Articulated Robotic Surgical System for Minimally Invasive Surgery
,”
Ann. Thorac. Surg.
0003-4975,
87
(
4
), pp.
1253
1256
.
17.
Eickhoff
,
A.
,
Van Dam
,
J.
,
Jakobs
,
R.
,
Kudis
,
V.
,
Hartmann
,
D.
,
Damian
,
U.
,
Weickert
,
U.
,
Schilling
,
D.
, and
Riemann
,
J. F.
, 2007, “
Computer-Assisted Colonoscopy (the Neoguide Endoscopy System): Results of the First Human Clinical Trial (“Pace Study”)
,”
Am. J. Gastroenterol.
0002-9270,
102
(
2
), pp.
261
266
.
18.
Ikuta
,
K.
,
Tsukamoto
,
M.
, and
Hirose
,
S.
, 1988, “
Shape Memory Alloy Servo Actuator System With Electric Resistance Feedback and Application for Active Endoscope
,”
Proceedings of the IEEE International Conference on Robotics and Automation
, pp.
427
430
.
19.
Yagi
,
A.
,
Matsumiya
,
K.
,
Masamune
,
K.
,
Liao
,
H.
, and
Dohi
,
T.
, 2006, “
Rigid-Flexible Outer Sheath Model Using Slider Linkage Locking Mechanism and Air Pressure for Endoscopic Surgery
,”
Medical Image Computing and Computer-Assisted Intervention—MICCAI 2006
, pp.
503
510
.
20.
Rösler
,
J.
,
Bäker
,
M.
, and
Harders
,
H.
, 2007, “
Mechanical Behaviour of Polymers
,”
Mechanical Behaviour of Engineering Materials
,
Springer-Verlag
,
Berlin Heidelberg
, pp.
257
293
.
21.
Jenkins
,
C. H.
, 2001,
Gossamer Spacecraft: Membrane and Inflatable Structures Technology for Space Applications
,
AIAA
,
Reston, VA
.
22.
Scarborough
,
S. E.
, and
Cadogan
,
D. P.
, 2006, “
Applications of Inflatable Rigidizable Structures
,”
Proceedings of the International SAMPE Symposium and Exhibition
.
23.
Griffin
,
S.
, 2006, “
Selectively Flexible Catheter and Method of Use
,” WO Patent No. 2006/060312.
24.
Kreyberg
,
L.
, 1949, “
Development of Acute Tissue Damage Due to Cold
,”
Physiol. Rev.
0031-9333,
29
(
2
), pp.
156
167
.
25.
Bell
,
G. D.
, and
Burn
,
K.
, 2001, “
Measurement of the Stiffness of Endoscopes—A Plea for Commonality
,”
Gut
0017-5749,
49
(
1
), p.
154
.
26.
Ellis
,
B.
, 2007,
Polymers: A Property Database
,
Taylor & Francis
,
London
.
27.
2009, “
Campus Plastics
,” CES Edupack Software.
28.
2009, “
Ides Plastics
,” CES Edupack Software.
29.
2009, “
Matweb Materials Property Database
,” Matweb, http://www.matweb.comhttp://www.matweb.com
30.
Foreman
,
J.
, 1997, “
Dynamic Mechanical Analysis of Polymers
,”
Am. Lab. (Shelton, Conn.)
0044-7749,
29
(
1
), pp.
21
24
.
31.
Allin
,
S. B.
, 2001, “
Introduction to Physical Polymer Science, 3rd Edition (Sperling, L. H.)
,”
J. Chem. Educ.
0021-9584,
78
(
11
).
32.
Chartoff
,
R. P.
,
Weissman
,
P. T.
, and
Sircar
,
A.
, “
Application of Dynamic Mechanical Methods to Tg Determination in Polymers: An Overview
,”
Proceedings of the ASTM Special Technical Publication
,
ASTM
,
Philadelphia
, pp.
88
107
.
35.
Biogeneral, Inc.
, 2009, “
Biogeneral—Bioabsorbable Medical Tubing and Monofilament
,” http://www.biogeneral.comhttp://www.biogeneral.com
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