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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_612_Библиотеки_им_академика_М_И_Перельмана
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tray should include micro or jeweler’s forceps, straight and curved
microscissors, dilators, needle drivers, microvascular Acland clamps,
and vein sizer (Figure 5.3A). Common microsurgical backgrounds
used during the anastomosis include neuro patties and colored
silicone background mats (Figure 5.3B). A sterile doppler ultrasound
should be available for intraoperative assessment of perfusion and to
confirm an external doppler signal at the end of the case.
Heparinized saline irrigation should be available in a 3-mL syringe
with an anterior chamber needle or 26-gauge angiocatheter tip.
FIGURE 5.3. A. Instrumentation. B. Example of a green-
colored microsurgery background mat, with each cubic
square indicating 1 mm for sizing of the vessel.
The microvascular anastomotic coupler (Synovis Micro
Companies Alliance, Birmingham, AL, USA) (Figure 5.4) is a singleuse implantable device used in the anastomosis of veins of calibers
ranging from 1.5 mm and greater. The coupler provides intima-tointima contact without intraluminal suture material. The vein is sized
appropriately using the sizer instrument. After loading the coupling
device with the appropriate size ring, the flap pedicle vein is passed
through the polyethylene ring, everted, and evenly secured to the
pins. Care is taken to avoid nearby valves for potential risk of
thrombosis. Next, the recipient vein is passed through the opposing
ring and secured in a similar manner. The coupler device is then
closed completely. A clamp can be used to ensure complete closure
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and approximation of both plastic rings. The coupler is proven to be
at least as efficacious as hand-sewn techniques and reduces
operative time.
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FIGURE 5.4. A. Anastomotic coupling device. B. Use of
an anastomotic coupling device. With the device’s lateral
wings open, each vessel is passed through a plastic ring,
and the vessel walls are everted and impaled on pins
mounted on the rings. C. After both vessels are mounted,
the knob is turned to close the wings and secure the rings
with the vessels in opposition. The rings are securely
attached to each other by the pins of one ring interlocking
with the opposite plastic ring. After the anastomosis, the
coupled rings are released in the direction of the arrow by
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continuing to turn the knob. (From Yap LH, Butler CE.
Chapter 8: principles of microsurgery. In: Thorne CH,
Bartlett SP, eds. Grabb and Smith’s Plastic Surgery, 6th
ed. Lippincott Williams & Wilkins; 2006:66-72, Figures 8.1-
8.8.)
Monofilament, nonabsorbable suture, usually nylon, is used to
perform anastomoses. Size ranges from 8- to 9-0 suture for standard
anastomoses of the breast, H&N, and limb salvage cases, up to 11-0
for lymphatic cases and digital replantation. Microneedles have a
sharp tapered tip and flat body, 50 to 130 μm in diameter.
Magnification
Microsurgical outcomes are less dependent on the method of
magnification used (ie, loupes vs microscope) (Figure 5.5A and B)
and more so related to surgeon experience and comfort with their
choice.25 When using loupes for microsurgery, most surgeons use
3.5× to 4.5× magnification, with up to 6× to 8× being use for smaller-
than-typical vessel and nerve work. Loupes provide an advantage
when operating at an angle or in a deep field. Expanded field options
prove helpful when performing the flap dissection and harvest. A
head light proves useful particularly when using loupes for
microsurgery, and this can be mounted onto the loupes or used as a
separate head piece.
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FIGURE 5.5. A. Standard 3.5× loupes, Xenosys, with
mounted headlight used for perforator dissection and
anastomosis. B. Conventional microscope used for the
microsurgical anastomoses. C. Symani Surgical System
robot being trialed.
The dual-surgeon operating microscope magnification typically
ranges from 6× to over 40×. A benefit of the microscope is the ability
to adjust the magnification with the press of a button. The xenon or
halogen light tends to be bright and completely illuminates the field
of focus, and the light brightness may also be adjusted. Most
microscopes also have video capabilities that allows others to view
what is happening in the field of focus. The microscope does require
sterile draping and it is best to initiate this process well in advance of
when it is needed so as to avoid unnecessary delays. The Mitaka
MM51 microscope is typically used at centers performing high
volumes of lymphedema surgery. It is the highest resolution
microsurgery microscope, with twice the resolution and magnification
of other surgical microscopes (42× magnification, 4K camera and
monitor, 8:1 zoom). It also offers multispectral ICG imaging with an
option to add fluorescein imaging capabilities.
Robotic Microsurgery
The concept of robotic assistance in microsurgery has been around
for several decades. Such a system like the Italian-designed Symani
Surgical System by Medical Microinstruments (Figure 5.5C) has the
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appeal of potentially greater precision, reproducibility, and efficiency
than standard microsurgical techniques.
MICROSURGICAL TECHNIQUES
The plan for first and backup flap choice, recipient site exposure,
patient positioning, and microscope positioning should be clearly
verbalized with all involved parties. Anesthesia and nursing
colleagues should be aware of suitable sites for intravenous and
arterial access that will not interfere with the operation, flap harvest,
or patient positioning. Given the duration of these cases, it is
particularly important to make sure that the patient is properly
positioned and that all pressure points are padded. A resulting
neuropraxia or wound from improper positioning should be never
events.
Anesthesia
An open discussion with the anesthesiology team should begin
preoperatively and continue throughout the operation. Anesthesia
goals should center around ensuring a safe airway that is best
positioned with respect to the operative site, maintaining
normothermia, ensuring adequate circulatory volume, mean arterial
blood pressure, and avoiding peripheral vasoconstriction. The type
of airway and where best to secure it should be confirmed prior to
intubation.
Both parties should agree with regard to need for invasive
hemodynamic monitoring, analgesic blocks and infusion catheters,
and method used for temperature monitoring. Various methods for
maintaining temperature homeostasis include under body Bair
Hugger, blankets, warmed intravenous fluids and surgical irrigation,
and controlling room temperature. Temperature control is as
important postoperatively as it is intraoperatively. Hypothermia
impairs the patient’s immune response and results in increased
blood viscosity and low-flow state, all of which are suboptimal in
microvascular reconstruction and recovery.
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Fluid underresuscitation intraoperatively may place the patient at
an increased risk of postoperative flap thrombosis, and urine output
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should be used to guide management. After ensuring adequate fluid
resuscitation, if a patient remains hypotensive, vasopressors may be
used with likely no impact on thrombotic events or flap loss.
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Ischemia Time
The time of flap pedicle ligation should be recorded as start of
ischemia time, and the duration from then until completion of the
anastomosis and reperfusion should be recorded as total ischemia
time. Muscle has less tolerance to ischemia when compared to
fasciocutaneous flaps, whereas bone flaps have the greatest ability
to withstand hypoxia.
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Anastomosis
The authors minimally excise adventitia and periadventitial tissue
from the edges of the vessels to be anastomosed for 1 to 2 mm of
length, as there is the potential for thrombus formation if the
adventitia becomes trapped in the vessel lumen (Figure 5.6). Less, if
any, adventitial trimming is performed of radiated vessels as they are
more fragile and more likely to delaminate and tear with excessive
trimming. The recipient vessels are then doubly clamped and divided
with enough resulting length such that the vessels can be swung into
a good position for the microsurgical anastomoses. It is best to
ensure a long vessel length and unimpeded surgical field when
preparing and ligating the recipient vessels. Retractors should be
placed and positioned such that the recipient and flap vessels are
widely visible and the overhead light can uninhibitedly illuminate the
field. For breast reconstruction, a generous stump of retrograde
vessels can be left in the event that these backup recipients become
necessary when the antegrade vessels are suboptimal or injured.
The authors do not routinely irrigate their flaps prior to anastomosis,
but the recipient vessels can be flushed to test the inflow to the flap
and remove any clot. Next a double-approximating microvascular
clamp is applied such that both vessel ends are “kissing” in a
tension-free manner (Figure 5.7).
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FIGURE 5.6 Donor and recipient vessel preparation. The
excess adventitial tissue near the cut edge of the vessel is
removed with dissecting scissors to prevent intrusion into
the lumen during the anastomosis. Care is taken to avoid
excessive thinning, which can result in vessel tears during
the placement of sutures. (From Yap LH, Butler CE.
Chapter 8: principles of microsurgery. In: Thorne CH,
Bartlett SP, eds. Grabb and Smith’s Plastic Surgery, 6th
ed. Lippincott Williams & Wilkins; 2006:66-72, Figures 8.1-
8.8.)
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FIGURE 5.7 Use of double-approximating microvascular
clamps. The donor and recipient vessels are placed within
the clamps, and the vessel ends are approximated along
the direction of the arrows. This technique maintains the
correct orientation of the vessels and facilitates suture
placement. After the anterior suture line is complete, the
clamps are turned over to allow access to the posterior
suture line. (From Yap LH, Butler CE. Chapter 8: principles
of microsurgery. In: Thorne CH, Bartlett SP, eds. Grabb
and Smith’s Plastic Surgery, 6th ed. Lippincott Williams &
Wilkins; 2006:66-72, Figures 8.1-8.8.)
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The end-to-end arterial anastomosis is familiar to all
microsurgeons and end-to-side proves useful for extremity
microsurgery to preserve distal limb perfusion (Figure 5.8). There are
several techniques used for suturing an end-to-end arterial
anastomosis, most commonly by first placing two separate orienting
sutures 180° apart through the recipient and donor vessel walls,
followed by three to four interrupted sutures evenly spaced in
between on the front and back wall. When suturing an end-to-side
anastomosis, a “heel” and “toe” stitch are first placed and tied to
approximate the flap vessel to the opening in the recipient vessel
wall, again followed by interrupted or running sutures on the front
and back wall to ensure complete intima to intima opposition without
gaps. Interrupted sutures are preferred in cases of size mismatch
between recipient and flap vessels. Differences in outcomes are less
related to interrupted versus continuous methods of suturing, but
more dependent on surgeon experience and comfort with the
technique employed.
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