Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5183_Библиотеки_им_академика_М_И_Перельмана.pdf
13112 Basics of Suturing and Knotting in Ophthalmic Surgery
cd
Due to the limited surgical field that the
surgeon sees through the microscope, it is
absolutely necessary to ensure a secure grip
the curve of the needle holder. This allows the
needle to be guided precisely and securely dur-
ing tissue penetration.
of the needle in the needle holder to achieve
a safe guidance for gentle suturing with the
lowest possible penetration force.
to clamp the needle at an angle (Fig. 12.1). In
these cases, the needle can only be securely
grasped for suturing with a straight needle
holder.
12.2.2 Needle Holder and Needle
area during clamping, it results in damage to the
Suturing begins with the selection of the needle holder and the clamping of the needle. For
corneal and conjunctival sutures, needle holders without a lock have become established in
ophthalmology. Many surgeons prefer curved
needle holders. In this case, the needle must be
grasped so that the convex curvature of the needle holder and the needle tip point in the same
direction and the needle forms a right angle with
ab
tip, making it blunt and hindering gentle tissue
penetration.
In case of improper handling, for example,
In special situations, it may be necessary
If the needle is accidentally grasped at the tip
after touching or bumping the needle tip,
bead-like thickening can be observed under
the operating microscope (Fig. 12.2). In this
case, it is strongly advised to replace the
damaged needle!
Fig. 12.1 The needle must form a right angle with the guiding line of the needle holder (a) to guide the needle pre-
cisely and securely during tissue penetration. In special situations, it may be necessary to clamp the needle at an angle
(b–d). (Mod. after 2)
132 F. Wilhelm et al.
of the surgeon’s hand results in an arched move-
ment that follows the curvature of the needle,
allowing the tissue to be penetrated gently with
minimal pressure and without significant defor-
mation (Fig. 12.4).
In selected situations, it may be necessary to
suture “away from oneself.” For this, the needle
Fig. 12.2 Bead-like thickening results from damage to
the needle tip
is held in the backhand position, and the arched
movement is performed through the pronation of
the hand. (This approach is necessary, for exam-
ple, when suturing corneal transplants.)
Grasping the needle too far at the proximal,
round end leads to twisting and can cause bending or even breaking during the suturing process.
It is recommended to clamp it at the transition to
the rear third (Fig. 12.3), but the optimal point
Care must be taken to pierce perpendicu-
lar to the wound edge to avoid shifting the
wound surfaces and distorting the tissue
when tightening the knot.
for grasping the needle also depends on the curvature, bending and breaking strength, and the
consistency of the tissue to be sutured.
It has proven effective to first pierce the needle
through only one edge of the wound and then
release the needle so that the needle tip indicates
The firmer the consistency of the tissue to
be sutured, the closer to the middle the needle must be clamped.
the direction in which the thread must be guided
through the second wound lip to achieve an
exact adaptation of the opposing fixation points
(Fig. 12.5).
Then, the needle is grasped again behind the
12.2.3 Fundamentals of Microsurgical
Suturing
tip and precisely pierced through the second
wound lip in the predetermined direction. This
approach is generally recommended for beginners
During the suturing process, the penetration is
dictated by the curvature of the needle. Since
suturing is generally done “towards oneself,”
the needle is held in the “forehand” position. It
is distinguished whether the surgeon is suturing with the left or right hand. The supination
and for experienced surgeons in difficult initial sit-
uations with swollen corneal stroma, as it results
in a secure and precise wound closure and mini-
mizes the extent of suture-induced astigmatism.
An exception is the double continuous diago-
nal suture in penetrating keratoplasty according
Fig. 12.3 It is recommended to grasp the needle between the middle and rear third of the curve
13312 Basics of Suturing and Knotting in Ophthalmic Surgery
a
b
Fig. 12.4 The suturing movement follows the needle curvature: (a) vertical insertion of the needle tip, (b) gentle
penetration of the tissue through the arched supination movement of the surgeon with the needle
running superficially and the other deep, results
in a clean adaptation without gaping.
For individual sutures on the cornea, it is
important that the wound edges are adapted at
the same depth with the opposite side (Fig. 12.6).
The extent of the inner wound gap depends on
the depth of the suture guidance.
For this purpose, the surgeon can enlarge the
image under the operating microscope as needed
so that the boundary between the stroma and the
Descemet’s membrane is clearly visible in depth.
The needle can then be controlled to pierce in
and out closely in front of it, achieving a secure
Fig. 12.5 The needle is pierced through the first wound
lip and then released by the needle holder to indicate the
direction in which the suture must be guided through the
second wound lip, ensuring that there is no shifting of
the wound edges against each other after the knot is tied
wound closure over the entire corneal thickness.
Since gaping wounds on the eye sur-
face are filled with granulation tissue
and often colonized by bacteria, incomto Hoffmann [7]. In this case, the needle is
pierced in and out at an angle to the wound
edge. The guidance of the two sutures, one
plete adaptation results in fistulas and
step formations, which can cause a for-
eign body sensation with subsequent
134 F. Wilhelm et al.
ab c
Fig. 12.6 Exact adaptation of opposing wound edges deep lamellar before the DM (a) ensures a tight wound closure,
which is not the case with different stitch distances (b) or penetration depths (c). (Mod. after 9)
vascularization in the patient and induce
higher astigmatism!
12.2.4 The limbus suture is started
rst!
Before closing any wound, it must be clarified at
which point the suturing will begin. In the case of
a cornea-sclera wound due to an injury, the first
suture must always be the limbus suture [12].
After that, it can be decided how many sutures
will likely be needed. These should be distributed successively according to the wound course
to arrange the distances between the individual
sutures in such a way that no tissue overlap results
[4]. Distortions and folds of the wound edges,
which mainly affect the cosmetic result on the
skin, cause significant astigmatism on the cornea.
Beginners in ophthalmic surgery should definitely opt for single button sutures again: interrupted on the cornea, the conjunctiva and on the
skin.
It is important to arrange the stitches in such
a way that a secure wound closure is achieved
with as few sutures as possible (Fig. 12.7).
With increasing experience, the single button
sutures can then be replaced by continuous
Fig. 12.7 When adapted by EKN, the wound edges are
sealed only in the area compressed by the suture. Leaks
can result in between! (Mod. after 4)
13512 Basics of Suturing and Knotting in Ophthalmic Surgery
or cross sutures. In the case of swollen and
jagged wound edges, it may be necessary
to temporarily place individual sutures as
“assembly aids” or situational sutures to better
place the final adaptation threads afterward.
Subsequently, the situational sutures should be
removed again. Especially when placing sev-
eral single button sutures with the same direc-
tion of pull, loosening of previously placed
threads can occur after the corneal stroma has
de-swollen. In this case, it must be decided
which suture needs to be replaced.
12.3 Knots
When tying a knot, some basic rules must be
observed. The thread ends must be sufficiently
long to form the knot at all. The length of the
longer thread end required to execute the knot
and grasp the short end depends on the number
of planned turns (Fig. 12.8).
The second thread end should, if possible,
not be too long, as loops can form when pulling
through, which can tighten and may not be easily
loosened. The short thread end is grasped with
the needle holder, then the long end is wound
around the instrument, and the short thread end
is pulled through the loop resulting from the
winding [6]. To practice the movement sequence
for the instrument knot, dry exercises on suitable
models are recommended (Fig. 12.9).
The needle itself must not be used to tie the
knot! It should be placed within the microscope field so that it does not need to be
searched for after cutting.
When tying with instruments, special care
must be taken to ensure that the edges of
the needle holder and forceps are smooth,
as otherwise the vulnerable thread can easily be damaged. This is especially important
Fig. 12.8 When tying with instruments, the thread ends must be sufficiently long to form the knot at all!
136 F. Wilhelm et al.
ab c
12.3.1 The First Knot
The first knot should be placed exactly as a
surgical knot in a double winding to increase
the friction between the thread loops and thus
counteract the separation of the wound edges
due to tissue tension. This knot must always be
tightened in the “running direction” of the loop.
Then it must be checked whether the tension is
sufficient or whether the wound edges distance
themselves from each other again due to tissue
tension.
Fig. 12.9 The movement sequence for the instrument
knot can be practiced on the model in the dry lab
when very thin monofilament suture material is used. Monofilament threads should
never be stretched too much, as they can
twist and possibly break.
Depending on the direction in which the thread
is looped during the execution of the second
winding, a “granny knot” or a “reef knot” is
formed [1]. While the reef knot usually adapts
the wound edges very stably through two individual loops, the granny knot leaves the possibility open that it can be tightened even more after
forming the second throw (Fig. 12.10). The reef
knot is also known from sailing as a square knot
[5], in which the two overlapping thread windings lock each other.
If the wound edges gape apart, one end of
the thread can be passed under the opposing
thread again to achieve an additional wind-
ing. This is gentler than reopening and re-
looping the knot.
At this point, the question arises as to how many
windings are necessary for the knot at all.
12.3.2 Number of Windings
The number of windings depends on both the
type of suture material and the tension of the tissue to be sutured. With high tissue tension and
monofilament material, more windings are necessary for a tight wound adaptation.
In principle, a knot should be tied with the
smallest possible number of windings to make
Fig. 12.10 a,b a Granny knot. b Square knot. c Surgical knot. (Mod. after 1)
13712 Basics of Suturing and Knotting in Ophthalmic Surgery
it overall smaller. This is not significant for skin
sutures that are removed early. However, large
knots on the conjunctiva and cornea lead to pain
and blepharospasm due to the foreign body irritation and are often not tolerated by patients.
12.3.3 Smooth or Overhand Knot
When forming the knot, a distinction is made
between a smooth knot and an overhand knot in
the first winding (Fig. 12.11). If the threads are
not tightened in the running direction, the knot
overhands and slides on the second thread end
(Fig. 12.12).
In principle, the two consecutive loops of
a knot should differ by only one winding
(Fig. 12.10), otherwise it overhands when
tightened and does not hold. However, the
knot becomes bulkier due to the increased
use of suture material, which is why it is
also recommended to deviate from this rule
for corneal sutures if necessary [8].
12.3.4 Burying the Knot
Corneal threads should be buried. Therefore, it
is necessary to design the knot particularly carefully here, to tighten it securely, and to cut the
thread ends as short as possible. This is best
achieved by cutting the tightly held monofilament thread close to the knot. It is broken over
the edge of a microscalpel (Fig. 12.13). In doing
so, the surgeon can precisely determine the distance to the knot, whereas when using scissors,
the knot may be obscured by the branches of
this instrument, making it difficult to accurately
estimate the length of the thread ends at the
knot.
This approach is recommended exclusively
for monofilament sutures to shorten the
ends with a single, controlled action.
When using multifilament suture material on
the skin and conjunctiva, this makes little sense,
as the thread would otherwise split into its individual fibers. Here, a suitable pair of scissors
should be preferred (Fig. 12.14).
When sinking the knots into the corneal tissue, care should be taken to ensure that the
threads can be removed as gently as possible
later. Therefore, after the knot has been rotated
into the deeper stroma, it is then rotated back up
to just below the surface. This aligns the thread
ends in the direction of pull, whereas if this
retraction is omitted, they act like small barbs
that, after fibrosis has formed around the knot,
make it difficult to remove the threads at a later
time (Fig. 12.15).
138 F. Wilhelm et al.
a
b
c
d
Fig. 12.11 (a–d) left side smooth/square knot, right side overhand knot. (Mod. after 4)
13912 Basics of Suturing and Knotting in Ophthalmic Surgery
c
b
a
Fig. 12.12 a–c With monofilament suture material, an additional securing loop c follows the adaptation knot a and
the securing loop b. (Mod. after 4)
Fig. 12.13 To break the monofilament suture close to
the knot over the edge of the microscalpel, the thread
must be held tightly!
140 F. Wilhelm et al.
cd
Fig. 12.14 The shortening of the thread ends to the
appropriate length is done with scissors for skin and conjunctival sutures
ab
Fig. 12.15 a–c After tying, the knot is tightened a and rotated into the corneal stroma b. This aligns the thread ends
so that they act like barbs c, which, particularly due to fibrosis after remodeling processes during wound healing,
makes it difficult to remove the knots. Therefore, the knots are rotated back up to just below the corneal surface by
pulling the thread in the opposite direction, aligning the ends in such a way (d) that the thread along with the knot can
be more easily removed
References and Further Reading
1. Becker T (1989) Kurzgefasster Operationskurs.
Johann Ambrosius Barth Leipzig. 315 S
2. Castroviejo R (1968) Keratoplastik. Thieme, Stuttgart,
p 453 S
3. Domarus v D et al (1996) Trauma, Operationen und
Wundheilung des Auges. In: Naumann GOH (Eds)
Pathologie des Auges, Band I, pp 301–377. Springer,
Berlin
4. Eisner G (1978) Augenchirurgie. Einführung in die
operative Technik. Springer, Berlin
5. Friedrichsen W (1986) Das Segelhandbuch.
Hoffmann und Campe, Hamburg