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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_605_Библиотеки_им_академика_М_И_Перельмана.pdf
302
Biomedical Engineering in Gastrointestinal Surgery
Graspers enable the surgeon to hold and manipulate organs and tissue,
comparable to forceps in open surgery. The design of the tip is always
a compromise between a firm fixation and the avoidance of tissue lesions
due to excessive compression.
To get a firm grip graspers with teeth are used, especially for robust
anatomical structures (
atraumatic forceps are available (
Fig. 7.40). For more delicate tissues, so-called
Fig. 7.41).
Atraumatic forceps allow for a more gentle fixation of soft tissue,
in particular the small and large bowel.
7.2.2 Dissectors
The dissector is used to “split” tissue bluntly—comparable to an Overholt
in open surgery (
Fig. 7.42). So-called “blunt dissection” is frequently used
Figure 7.40 Unilateral grasping forceps with a robust stable articulation of one
movable branch (e.g., for the stomach or a thickened gallbladder wall): (A) opened;
(B) closed. Note the space between the branches. From MITI.
Figure 7.41 Atraumatic forceps: The long, slim, and blunt branches enable to fix soft
tissue securely without the danger of laceration. From MITI.
Operative (Surgical) Laparoscopy
Figure 7.42 Dissector: The tip has a bent shape to enable very delicate dissection.
The angle of the tip varies, but is limited by the inner lumen of the trocar. Dissectors
are usually connected with the electrosurgical generator to apply electrocoagulation
if required. From MITI.
303
to divide different tissue layers without bleeding. Vessels are isolated and
selectively coagulated.
The majority of laparoscopic procedures require a mixture of sharp
and blunt dissection techniques. Blunt dissection avoids bleeding reliably,
if the proper layers are respected.
7.2.3 Scissors
As compared to open surgery, the use of scissors in minor access surgery
is more limited. They require greater skill since they are potentially
harmful.
Scissors are offered with straight, curved, or hook blades. The edges
can be serrated to prevent tissue slipping out of the blades (
Curved scissors allow a better visual control during cutting and are
generally preferred in laparoscopic surgery. To some degree they are
similar to the Metzenbaum scissors of open surgery.
A type of scissors almost exclusively used in laparoscopic surgery are
hook scissors. The blades encircle the object to be cut before it is dissected
(
Fig. 7.44).
The hook scissor is the only scissors that severs the tissue from distal
to proximal. Thus, tissue slipping out of the branches is impaired.
Scissors may also be used to apply (monopolar) electrocoagulation
to (small) vessels. However, the blades soon loose sharpness. If
electrocautery has to be used often dur ing one procedure, the use of
Fig. 7.43).
304
Biomedical Engineering in Gastrointestinal Surgery
Figure 7.43 Curved scissors with serrated blades. The fine teeth prevent tissue slipping out of the scissors when the blades are closed. From MITI.
Figure 7.44 Hook scissors: Both blades are excavated. Robust anatomical structures
can be cut easily, but they are less suitable for delicate tissue preparation. From MITI.
disposable scissors is preferable (Fig. 7.45). The selection of blades is
limited with d isposable scissors.
As compared to high quality reusable scissors, disposable ones do not
offer the very smooth and sensitive function as one is accustomed to in
the other case. Nevertheless they are well suited for clinical use.
7.2.4 Needle Drivers
Needle drivers are tools to enable to sew and tie sutures in laparoscopic
surgery. They have to transport the sutureneedle combination into the
abdominal cavity and must fix the needle in a stable position when the
needle is pierced through the tissue (
The gilding indicates that the jaws of the tip are of supreme quality.
They can be exchanged when worn out.
As in all needle holders, an easy and reliab le locking mechanism is decisive.Incontrasttoopensurgery,laparoscopic needle holderhandlings/locking mechanisms of various different types are availabl e (
Fig. 7.46).
Fig. 7.47).
Operative (Surgical) Laparoscopy
Figure 7.45 Disposable curved scissor. Inset: Clearly recognizable: The blades are
simple stamped parts. From MITI.
Figure 7.46 Curved needle in the jaws of the needle holder. Tilting of the needle
must be reliably prevented as well as mechanical damage to the needle. From MITI.
305
Figure 7.47 Needle holders: (A) With “inline” handling; (B) with typical laparoscopic
angulated handling. From MITI.
To ensure a firm grip of the needle without causing damage, the surface
of the jaws requires particular craftsmanship. Accordingly, they are expensive.
7.2.5 Retractors
In laparoscopic surgery, the task of creating enough space for the surgical
manipulation is certainly even more difficult than in open surgery.
Retractors are designed to keep aside the adjacent anatomical structures.
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Biomedical Engineering in Gastrointestinal Surgery
Figure 7.48 Various types of laparoscopic retractors: (A) Disposable 10-mm retractor,
opened by turning the knob; (B) reusable retractor, opened by shifting the sleeve.
From MITI.
Due to the peculiarities of laparoscopic surgery, they differ in shape significantly from those used in open surgery (see Chapter 6.1.5: Retractors)
(
Fig. 7.48).
The challenge is to insert the retractor through a trocar of limited diameter and to unfold afterward a retracting surface as large as possible. Up to
now, much potential is existing for the development of better designs.
7.2.6 Laparoscopic Electrosurge ry
As in open surgery, electrosurgery is a valuable tool to make surgery safer
and faster.
Of course, the disruptive processes that result from electric current
running through tissue are identical in both cases, but laparoscopic application requires specially designed application tools. Again, monopolar and
bipolar modes are in use. Monopolar instruments may be applied in the
cut or the coagulation mode. In addition to specially designed unipolar
electrodes like hooks or spatula (
graspers or bilaterally movable instruments as scissors (see
Scissors) can also be used for electrocautery (
In laparoscopic surgery, bipolar instruments are even more popular
than in conventional surgery. Bipolar coagulation devices are typically
designed as forceps with isolated electrodes in the beak (
However, the power which can be applied is comparatively lower.
Smaller blood vessels can be successfully sealed.
Fig. 7.49), single usable instruments like
Section 7.2.3:
Fig. 7.50).
Fig. 7.51).
Operative (Surgical) Laparoscopy
Figure 7.49 Unipolar curved hook: Many different designs are available for the
same purpose: To elevate or to pull an anatomical structure selectively in order to
cut/coagulate it. From MITI.
Figure 7.50 Additional unipolar electrosurgery tools: (A) Grasping forceps; (B) suction/
irrigation probes. From MITI.
307
The generator/control unit is identical to those used in open surgery
(see Chapter 6.2: Electrosurgery).
7.2.7 Clips and Clip Appliers
Tubular structures like blood vessels or the cystic duct are commonly occluded
by ligatures in open surgery. Principally this could be done in laparoscopic
surgery as well, but since it is easier and faster, the v ast majority of closures are
performed with clip appliers. Reusable clip appliers deliver one clip at a time
(size varies approximately from 7 to 9 mm) and must then be taken out and
reloaded. When clip applie rs are used in pairs, the scrub nurse alw a ys has one
loaded, ready to exchange for the empty one which the surgeon withdraws.
It is cost-effective and causes minimal delay. Most disposable clip appliers
come loaded with 20 clips per unit, which can be applied in rapid succession
without removing the instrument fr om the abdominal cavity (
Absorbable clips are typically made of polydioxanon. Metal clips are
produced of titanium. It does not react with the human body and can be
left without problems at its site (
Fig. 7.53).
Fig. 7.52).
308
Biomedical Engineering in Gastrointestinal Surgery
Figure 7.51 Bipolar laparoscopic coagulation forceps. The “active” electrode and
the “return” electrode are more or less symmetrical and close together. At the tip
the blue isolators between the blades are clearly visible (Inset: arrow). From MITI.
Figure 7.52 Laparoscopic clips: (A) The absorbable clips have an integrated locking
mechanism, while (B) titanium clips are simply closed by deformation. From MITI.
However, metal clips may migrate in the postoperative course.
Perforation into the bile duct or the bladder have been published
[10].
In more complex surgeries with multiple vessel dissections, multifire
clip appliers are more economical. Repetitive clip application is by far
more rapid than reloading each single clip (
Fig. 7.54).
7.2.8 Laparoscopic Stapling Devices
Basically, laparoscopic stapling devices are more or less technically similar to
those as used in open surgery (see Chapter 6.5: Stapling Devices).
Modifications in design, however, were inevitable to insert them through
trocars.
Operative (Surgical) Laparoscopy
Figure 7.53 Clip applier for absorbable clips. Inset: The jaws are designed to make
the clips to start occlusion at its tips. Thus, tissue is prevented from slipping out.
From MITI.
Figure 7.54 Disposable clip applier with consecutively applicable clips. From MITI.
309
Currently available linear staplers are highly sophisticated devices
which enable the surgeon even to rotate and to bend the shaft (
Fig. 7.55).
As soon as the first linear staplers became available, the range of laparoscopic surgery was significantly widened. Even the creation of circular
(triangulated) anastomoses was attempted.
Circular staplers, however, are identical to those of open surgery
(
Fig. 7.56).
Accordingly, their use is confined to the distal end of the colorectum.
For more than a decade laparoscopists have been waiting for a flexible
anastomotic device which could be applied in all sections of the gastrointestinal tract. Former approaches did not function reliably and had to be
taken away from the market.
7.2.9 Laparoscopic Ultrasound Dissection
Even more than in open surgery, bleeding has to be avoided in minimally
invasive surgery since the removal of blood out of the surgical field is
considerably more cumbersome. Accordingly, the introduction of ultrasonic dissection devices was a significant leap forward, extending once
more the range of laparoscopic procedures.
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Biomedical Engineering in Gastrointestinal Surgery
Figure 7.55 Linear stapling device: The length of the stapling line may vary from 30
to 50 mm (in this case: 45 mm). If the white lever is activated, the instrument
is closed: the flat, mobile anvil is pressed against the magazine part. The tissue
in between is compressed but still left intact. If necessary, the device can be opened
again and brought into a better position. If the dark lever is pushed, the clamps
(clips) are compressed and the tissue is severed. From MITI.
Figure 7.56 Circular stapling device (see Chapter 6.5: Stapling Devices). The
clamps are located in the main device, after firing these are bent in the removable anvil, at the same time a circular kni fe (not visible) opens the lume n inside
the stapled colon. From MITI.
Ultrasonic cutting is based upon a mechanical impact on the tissue (see
Chapter 6.3: Ultrasound Dissection). Accordingly, it can be used even in
patients with cardiac pacemakers in whom electrosurgery has to be avoided.
Since laparoscopic ultrasound devices have to be inserted into the
abdomen via a trocar, their design has to be accordingly adopted. The
instrument has to be longer and has to have a smaller diameter (5 mm)
than in open surgery (
Ultrasonic scissors are suitable not only for cutting (
also for blunt dissection (
Fig. 7.57).
Fig. 7.58A) but
Fig. 7.58B).
As already mentioned in Chapter 6.3: Ultrasound Dissection, ultrasound
dissection inevitably produces surgical plume
space is soon full of plume deteriorating significantly visibility
[11]. The confined abdominal
[12].
Operative (Surgical) Laparoscopy
Figure 7.57 Disposable ultrasonic shears. The blade is vibrating against the mobile
branch which is covered by synthetics or ceramics (on reusable shears). (A)
Completely assembled instrument; (B) Tip: The mobile arm is in an oblique (open)
position. From MITI.
Figure 7.58 Laparoscopic ultrasound dissection: (A) Dissection of the short gastric
vessels; (B) excision of the gallbladder. All from MITI.
311
Both the amount and the movement of plume are pivotal [13].Currently
available remedies are less than satisfactory .
The change of the intraabdominal gas is time-consuming and tedious.
The options of modifying the blade design are limited
cessing may be helpful (
Fig. 7.59).
[14]. Image pro-
7.2.10 Impedance-Guided Dissection
Conventional electrosurgery has the main drawback that it is self-limiting.
Desiccated and charred tissue gains increasingly resistance and stops the
influx of power.
As described in detail in Chapter 6.2: Electrosurgery, the problem of
self-insulation is overcome by impedance-controlled electrocoagulation.
The first designs of impedance-controlled vessel sealing systems were
produced for laparoscopic surgery (
Impedance-controlled vessel sealing systems act in the bipolar mode.
Per se, they are unable to achieve more than—though very effective—
welding of the tissue and vessels. Dissection has to be done by a blade
integrated into the device. As soon as the coagulation process is finished
Fig. 7.60).