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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_605_Библиотеки_им_академика_М_И_Перельмана.pdf
374
Biomedical Engineering in Gastrointestinal Surgery
Figure 9.23 The commercially available OverStitch suturing system. Head of the
instrument. Inset: Handling system mounted to the endoscope. From Apollo
Endosurgery.
Figure 9.24 Flexible endoscopic stapler device. From Sodergren M, Clark J, Beardsley
J, Bryant T, Horton K, Darzi A, et al. A novel flexible endoluminale stapling device for use
in NOTES colotomy closure: a feasibility study using an ex vivo porcine model. Surg
Endosc 2011;25:326672
[20].
Combined Laparoscopic-Endoscopic Procedures and NOTES
Figure 9.25 The GERDX system: (A) The handling of the device which is guided by
means of a small bore gastroscope introduced via the camera channel. (B) The arms
at the distal end are opened and closed manually using a microhydraulic system.
(C) The pledgeted pretied sutures applied to a model. All from G-SURG GmbH.
375
developed at that time actually survived. One of them is the so-called plicator principle: by means of specially designed fixation elements (clips,
sutures, rivets), the fornix wall of the stomach is approximated to the lower
esophageal sphincter. This principle was also used to occlude gastric perforation as well as for the closure of the NOTES entry site.
One or two applications are usually sufficient to occlude the NOTES
entry site in the stomach. Currently, two systems are commercially available. The GERDX system (
Fig. 9.25) from G-SURG, Germany, and the
MUSE from Medigus, Israel.
9.2.5 Rivets
The riveting principle was applied in an experimental design.
The endorivet was primarily designed for gastric lesions. Since the
sharp tip of the needle is produced from magnesium, it will be soon
destroyed by gastric acid, thus becoming unable to hurt the mucosa
(
Fig. 9.26).
Much has already been attained in the closure of enterotomies after
NOTES, but there is still a need for further advances. In particular, low
diameter, fully flexible stapling devices could become extremely helpful.
9.3 SPATIAL ORIENTATION
Commercially available flexible endoscopes were developed for use in
cavities of relatively small diameter like the stomach or the colon. As
compared to these lumina, the abdominal cavity is a huge space, bringing
the effectiveness of normal endoscopes to their limit (
Fig. 9.27).
376
Biomedical Engineering in Gastrointestinal Surgery
Figure 9.26 The endorivet: (A) The sharp tip of the rivet is inserted into the proximal
edge of the lesion. (B) As soon as it has perforated the distal edge, the distal stopper is
unfolded. (C) The proximal stopper is unfolded. (D) By approximation of the stopper,
the distance between the two edges is gradually reduced until the lesion is occluded.
(E) The rivet is set free. (F) Application of the next rivet. All from MITI & Institute of Micro
Technology and Medical Device Technology (MiMed), Technische Universität München.
Figure 9.27 Limits of normal endoscopes: Image distortion. At larger distances, the
shape of anatomical structures is falsified. All from MITI.
The illumination of flexible endoscopes is not optimized for these
large spaces in combination with the wide-angle lenses. Therefore, only
organs comparatively close to the endoscope are clearly visible which
makes orientation and surgical manipulation even more difficult.
Spatial orientation depends on visualization. Visualization is the sum
of sufficient insufflation to create the necessary space, a powerful illumination, and a high-quality camera system. In addition, endoscopes have to
be steerable under strictly controlled and reliable conditions.
The most relevant needs should be briefly addressed.
9.4 ILLUMINATION
Flexible glass fibers are limited in delivering the amount of light which
is required in the peritoneal cavity. An alternative could be the use of
Combined Laparoscopic-Endoscopic Procedures and NOTES
Figure 9.28 The problem of homogenous brightness: The image might be either too
dark (A) or overexposed (B). Most often it is a combination of both with a too bright
center and darkness in the periphery. (C) High dynamic range sensors lead to a better visibility. From MITI.
377
light-emitting diodes since they are comparatively small. Since only thin
cables are required for power supply, the diameter of the instrument can be
kept small. However, some drawbacks like heat production still have to be
solved. Theoretically , the use of satellite cameras (see Chapter 7.3:
Minilaparoscopic Procedures) could be an additional option. Last but not least,
it can be expected that the progress in photonics will lead to more efficient
optical sensors. High dynamic range sensors would be able to provide better
visibility of both objects in the center as well as in the periphery (
Fig. 9.28).
9.5 FOG/MIST ELIMINATION
The negative effect of fog and mist on visualization has already been mentioned before (see Chapter 7.2.9: Laparoscopic Ultrasound Dissection). In
NOTES this problem is even more relevant. Gas exchange is less rapidly
feasible than during laparoscopy
[21]. Accordingly, new technologies to
eliminate the mist problem would be of particular value for NOTES.
9.6 STABILIZATION OF THE HORIZON
In flexible endoscopy it is impossible to maintain a strictly horizontal
view which is of minor importance in endoluminal endoscopy. In
NOTES, however, this becomes a serious problem since the perception
of the surgical site is massively impaired.
378
Biomedical Engineering in Gastrointestinal Surgery
Figure 9.29 Rectification of the horizon. Left: Native image showing the esophagogastric junction. Usually, one expects the junction (arrow) at the top. The oblique
view deteriorates intuitive perception of the anatomical plane. Right: After rectification. From MITI.
The automatic rectification is technically already feasible today as
shown in Chapter 11.6: Inertial Tracking Systems (
Fig. 9.29).
9.7 VIEW EXTENSION
The problem of a limited field of view could be overcome by mosaicing
or image stitching procedures. Since the field of view is particularly small
in NOTES, view extension would be extremely helpful.
9.8 THREE-DIMENSIONAL STEREOSCOPY
Up to today, no stereoscopic flexible endoscopes are commercially available . It
is conceivable that 3D vision could additionally ease NOTES performance.
9.9 MULTIFUNCTIONAL ENDOSCO PES AND MECHANICAL PLATFORMS
Beyond of the problems described above, a wide range of additional technical challenges has still to be mastered. All of them relate to the surgical platform. Initially it was thought that just something as a new “superendoscope”
would be required. Today it has become clear that more than an upgraded
endoscope is necessary. Soon, quite a number of dedicated designs appeared.
Before they are discussed in detail, a brief overview upon currently
existing systems is given. The considerable number of different platforms is
classified according to the EURO-NOTES classification (
Table 9.3) [22] .
Table 9.3 Classification of NOTES platforms [22]
Mechanical platforms,
e.g.
Computer-assisted
platforms
379Combined Laparoscopic-Endoscopic Procedures and NOTES
Nontethered systems
(“capsules”)
R-scope
NeoGuide
Transport
Cobra
Direct drive
endoscopic system
EndoSamurai
Anubis
MASTER
mod. DaVi nci
HVSPS
IREP
Viacath
Mechanical capsules
Magnetic capsules
Oleynikov device
The EURO-NOTES did not leave doubts that mechanical platforms
most probably will not be suitable to respond to the specific technical
challenges of advanced NOTES. The group strongly recommended
computer-assisted platforms.
Notwithstanding, several mechanical platforms had already been
created by industry.
Bardaro and Swanstro¨m did define some specific requirements for this
type of mechanical platform (
Table 9.4).
Supposedly the first was the “R-scope” of Olympus.
The R-scope was the first response of Olympus to meet the require-
ments of stability and triangulation for NOTES interventions (
Fig. 9.30).
The endoscope has a diameter of 13.5 mm with two articulated 2.8-
mm working channels with vertical and horizontal lifting gates. The
channels are arranged at right-angles to each other enabling simultaneous
separate movements of the instruments in perpendicular planes. This
allows off-axis movements, thereby improving tissue handling and raising
the potential for its use in transluminal settings
[23].
9.9.1 Endosamurai
The next coup of Olympus was the Endosamurai design.
The system consists of an endoscopic unit, an overtube, and two flexible
arms. The overtube stabilizes the device once locked into place (
The two arms are in parallel during insertion of the endoscope and can
be opened out and controlled with laparoscopic-like handles. The manipulator arms have working channels through which flexible instruments can
be deployed and an additional channel through the working shaft.
Fig. 9.31).
380 Biomedical Engineering in Gastrointestinal Surgery
Table 9.4 Requirements for endoscopes to be used for NOTES
Size The shaft should be between 18 and 22 mm in diameter
and should contain at least three channels ranging in
size from 3 to 6 mm. One channel for imaging and at
least two other channels to maneuver instruments.
Image The image should have sufficient resolution and adequate
illumination to distinguish different anatomical
structures. These requirements can be met with the
current state of digital imaging used in present day
endoscopes and laparoscopes.
Insufflation The device should have high flow CO
create sufficient pneumoperitoneum so that there is
adequate space to maneuver the instruments safely.
Because intraperitoneal pressures in excess of 15 mmHg
are injurious, systems that control intraperitoneal
pressure are needed.
Suction/irrigation The device should be able to efficiently remove blood,
blood clots, and fluids from the surgical field. Managing
potential complications require their prompt
recognition and proper instrumentation for timely
intervention.
Maneuverability The tip of the device should have the ability to maneuver
in all planes: vertical, horizontal, and lateral and the
shaft should have the ability for 180˚ retroflexion.
Stability The device should allow complete flexibility for insertion
and positioning with subsequent rigidity of the shaft
and continued flexibility of the tip. ShapeLock
technology currently available could solve this
requirement.
Triangulation It should give the surgeon the ability to manipulate tissue
with tract ion and countertraction in all planes. In order
to accomplish this task, efficient grasping technology
and a wide multitasking platform need to be developed.
insufflation to
2
9.9.2 Anubis
Anubis was the answer of STORZ to the NOTES challenge.
It consists of a four-way articulating endoscopic shaft 16 mm in
diameter and 110 cm long with a 16-mm vertebrae flexible section. The
18-mm distal tip of the device is tulip-shaped and acts as a blunt trocar
tip during insertion, preventing injury to surrounding structures. When
at the site of interest, the wings comprising the tulip-shaped distal tip
Combined Laparoscopic-Endoscopic Procedures and NOTES
Figure 9.30 R-scope: The first “super-scope” (Olympus, Tokyo, Japan): (A) Schematic
drawing. (B) View of the R-scope. From MITI.
381
Figure 9.31 The Olympus “Endosamurai”: Handling system.
open out, allowing two opposing flexible arms to emerge from working
channels located within the wings.
Interchangeable tools can be deployed down the working channels of
the arm and a central working channel in the shaft device enables triangulation of up to three instruments. The wings limit the use of the device
in confined workspaces (
Fig. 9.32).
9.9.3 SPOT (Single Port Overtube System), Technische Universität München
This is a new development for endoluminal endoscopy and NOTES
which was developed at the Technische Universita¨tMu¨nchen, Germany
(
Fig. 9.33). This overtube with two manipulating arms and a camera arm
is produced by 3D printing. The fully flexible structure envelopes the
commercially available dual-channel endoscope.
382
Biomedical Engineering in Gastrointestinal Surgery
Figure 9.32 The STORZ Anubis system: (A) Handling system; (B) Tip of the instrument. Courtesy: KARL STORZ GmbH & Co. KG.
Figure 9.33 Design of the Single Port Overtube System: (A) (1) Entire overtube consisting of the central channel for the endoscope (2) and the surgical tip (3) with two
flexible manipulation arms (4) with working channels for exchangeable instruments
and an additional arm for the camera (5). (B) Transfer of a lightweight object from A
to B (Inset: Mechanical handlings). From (A) MITI and (B) r D. B. Roppenecker, Y. S.
Krieger, S. V. Brecht, T. C. Lueth, Institute of Micro Technology and Medical Device
Technology (MiMed), Technische Universität München.
Mechanical control is provided by a harness-like unit worn by the
endoscopist.
All commercially available flexible instruments can be used to perform
the required steps of the surgical manipulation (
Fig. 9.34).
3D plotting enables low cost production. The SPOT is for single use,
thus avoiding the problems of postprocessing. Custom-made issues (e.g.,
diameter of the “mother” endoscope) can easily be provided.
The enumeration of mechanical systems is not at all complete.
Numerous similar prototypes are under research in laboratories all over
the world. Nonetheless, none of the devices have become part of routine
patient care up to now.
Computerized platforms (“robots”) and nontethered systems are
described in Chapter 10, Mechatronic Support Systems and Robots.
Combined Laparoscopic-Endoscopic Procedures and NOTES
Figure 9.34 (A) Specially designed mechanical interfaces for SPOT: The working conditions are similar to (conventional) endoscopy. (B) Experimental endoscopic submucosal
resection (ESD). All: Courtesy: Prof. Dr. A. Meining, University of Ulm.
383
9.10 OUTLOOK
Though the advances in R&D were impressive up to now, the instruments and devices which are currently available for NOTES are still far
away from being perfect. Retrospectively, the technological challenges
and pitfalls were certainly underestimated in the beginning
compared to the introduction of laparoscopy, the introduction of NOTES
is proceeding far more slowly (
Fig. 9.35).
In addition, patient request for the new procedure is not as strong as
seen with laparoscopic cholecystectomy 25 years ago and is lacking as a
major driving force for development. There is no doubt that the initial
euphoria of the years 20079 has vanished
[26] but more recent
figures indicate again a growing interest.
The best overview on the development of NOTES is probably provided in Germany due to a very systematic registration of almost all cases
in the German NOTES registry. At the beginning of 2016, more than
4000 cases were included, in the majority cholecystectomies and appendectomies via the transvaginal route (
Fig. 9.36).
The development in NOTES resembles the well-known hype cycle of
innovation: after phase 1 (until 2007) the second phase of inflated expectations began in 2008 and lasted until 201113 ending in the trough of disillusionment. There are some hints that we are now entering the slope of
enlightenment. Most remarkably, this is not due to advances in the initial
fields like appendectomy or cholecystectomy, but due to surprising new
applications such as the treatment of achalasia (peroral endoscopic myotomy)
or transanal surgeries
[27]. The last phase—the plateau of productivity—can
only be reached by further support of BME.
[24,25].As