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_612_Библиотеки_им_академика_М_И_Перельмана
.pdf
site. In 2006, Hallock demonstrated the perforator-based propeller flap,
in which the island skin flap can be rotated up to 180° around a
skeletonized perforator.
12
Described by Behan in 2003, the keystone flap is a curvilinear
trapezoidal flap comprised of two opposing V-Y advancement flaps
oriented parallel to the longitudinal axis of the defect.13 It is essentially
a type A multiperforator fasciocutaneous flap that is designed by
creating a right angle at the limits of the defect and marking a width that
is equivalent to the width of the defect. The ends are closed in a V-Y
fashion to relax the horizontal tension. Blunt dissection is performed
around the limits of the flap, taking care to avoid dissection underneath
the flap to preserve the perforators. Adjunctive maneuvers, such as
release of the deep fascia along the outer curvature, skin grafting of the
donor site, the use of an identical keystone flap on the opposite side of
the defect, and rotation with partial subfascial undermining, can also be
utilized.
Chimeric Flaps
Greater agility with perforator flaps paved the way for chimeric flaps,
which are composite and compound flaps in which different tissue
types (such as skin, muscle, and bone) are independently mobile with
separate blood supplies all based on a single mother pedicle.14 Such
flaps are well suited for complex, three-dimensional defects involving
multiple components. The presence of a single source vessel is
particularly useful if there is a paucity of recipient vessels because of
oncologic resection, trauma, radiation, or the need to preserve vessel
runoff in an extremity. Disadvantages to chimeric flaps include
increased operative time, steep learning curve, potential perforator
variations requiring alterations in surgical planning, limitations because
of tension between components, the possible need for additional
venous drainage, and donor site morbidity resulting from excessive
tissue harvest from a single location.
FREESTYLE FLAPS
Building upon their experience with perforator flaps, Wei and Mardini
used Doppler ultrasonography to map out cutaneous vessels and
develop freestyle flaps with skin islands designed over an identified
https://t.me/med1917
perforator or cutaneous vessels.15 In this technique, retrograde
dissection is utilized to trace a cutaneous vessel identified by Doppler
to a vascular pedicle of adequate vessel length and/or size. This
method permits the harvest of cutaneous islands without regard for the
course of the source vessel, thereby providing greater versatility in flap
choice and design. They can be performed either as pedicled or free
flaps and may theoretically be based on any of the hundreds of
perforators previously identified by Taylor and Palmer.
2,16
SUPERMICROSURGERY
Supermicrosurgery is defined as the dissection and anastomosis of
small vessels ranging from 0.3 to 0.8 mm and single nerve fascicles.
17
First introduced by Koshima in 1997, this technique has further pushed
the boundaries of reconstruction with seemingly infinite ability for flap
customization with minimal donor site morbidity and increased
functional recovery.18 Perforator-to-perforator anastomosis may permit
shorter operative time in some instances given the limited dissection
required, as well as the harvest of flaps from easily concealed areas. It
has revolutionized lymphedema treatment, distal fingertip amputation
salvage, and nerve reconstruction; the applications are nearly
endless.
19
CLINICAL EXAMPLES
The following examples provide a brief overview of some of the more
common flaps, organized by body area, proximal to distal. All of these
flaps are critical components of a reconstructive surgeon’s
armamentarium.
Pectoralis Major Muscle Flap
The pectoralis major originates along the anterior surface of the medial
clavicle, the anterior surface of the sternum, the costal cartilages of ribs
1 to 6, and the anterior layer of the rectus sheath; it inserts at the crest
of the greater tubercle of the humerus. It is a Mathes and Nahai type V
muscle.5 Its major blood supply arises from the thoracoacromial artery,
with secondary supply from the lateral thoracic artery, branches of the
internal mammary artery, and perforating branches of the anterior
intercostal arteries. The course of the thoracoacromial artery is
https://t.me/med1917
approximated by a line from the acromion to the xiphoid process. The
overlying skin is supplied by branches of the internal mammary and
anterior intercostal arteries primarily.
Indications
The pectoralis major muscle or myocutaneous pedicled flap is a
workhorse flap first described by Hueston and McConchie for sternal
reconstruction and Ariyan for head and neck coverage.
20,21
The advent
of microvascular free flaps has led to its use as a last resort or salvage
technique in the head and neck, but it often remains as the first choice
for sternal wound defects. It is possible to utilize the pectoralis major
muscle as a free flap, but it is rarely done as other flaps with longer and
larger pedicles with less donor site morbidity are often available.
Surgical Technique
Sternal reconstruction is often achieved with unilateral or bilateral
muscle advancement based on the thoracoacromial artery. The muscle
is accessed through the wound, which may be extended if needed for
complete dissection of the superior, medial, inferior, and lateral muscle
borders. If necessary, the muscle can be disinserted from the humerus,
often through a counterincision, for additional medial advancement.
Alternatively, the pectoralis muscle can be utilized as turnover flap
based on multiple medial intercostal perforators. This can be
particularly useful if bulkier muscle is required.
For head and neck reconstruction, the pectoralis major muscle is
most commonly rotated superiorly on the thoracoacromial artery.
Several factors need to be considered in terms of flap design, including
the need for a cutaneous component (single or double skin paddles
have been described) and breast size and shape in female patients. It
can also be combined with other flaps or manipulated through a variety
of previously described methods to customize the flap to the patient’s
needs. In general, if just the muscle is being harvested, the incision is
usually made in the inframammary fold in women or along the inferior
border of the muscle in men. If a myocutaneous flap is required, the
skin paddle is most often centered over the inferior portion of the
muscle. The skin is elevated from the underlying muscle (except for the
skin island in the case of a myocutaneous flap) and the muscle is
https://t.me/med1917
dissected off the chest wall. Care should be taken to preserve the
thoracoacromial pedicle, which lays along the undersurface of the
muscle. A counterincision is often made just below and parallel to the
clavicle to facilitate the skin tunnel to the defect superiorly.
Donor Site Considerations
The scar from flap harvest may be easily covered by clothing, but
harvest may result in breast asymmetry in female patients. In addition,
patients may endure decreased shoulder and upper extremity range of
motion and function as a result of muscle loss.22 It is also possible that
pectoralis major harvest may result in compromised pulmonary
function, although it is likely to only be evident in those with severe
pulmonary disease.
23
Rectus Abdominis, Deep Inferior Epigastric, and
Superficial Inferior Epigastric Flaps
The abdomen is one of the most common donor sites for flap harvest,
particularly for breast and pelvic reconstruction. The rectus abdominis
originates on the public symphysis and crest and inserts on the xiphoid
cartilage and the costal cartilages of ribs 5 to 7. It is a Mathes and
Nahai type II muscle with a dual blood supply originating from the deep
and superficial inferior epigastric arteries (SIEAs), with the deep system
being more reliable.5 The muscle can be harvested alone or as
myocutaneous flap with the skin paddle oriented vertically (vertical
rectus abdominis myocutaneous [VRAM] flap) or transversely
(transverse rectus abdominis myocutaneous [TRAM] flap). If muscle is
not required, perforator flaps may be raised on either the deep or
superficial inferior epigastric systems.
Indications
The rectus abdominis muscle flap is a reliable flap that can be used to
provide bulk for defects throughout the body. It is most commonly
applied as a pedicled VRAM flap for perineal reconstruction but can
also be a good option as a free flap for head and neck reconstruction.
The pedicled or free TRAM was a workhorse flap for breast
reconstruction but has since been replaced by the deep inferior
https://t.me/med1917
epigastric perforator (DIEP) flap as the standard of care.24 The SIEA
perforator flap is an alternate for breast reconstruction, but is less
reliable because of anatomic variability in pedicle diameter, pedicle
length, and arterial adequacy with a consequent higher risk of arterial
thrombosis.
25
Surgical Technique
The procedure begins with an incision along one side of the flap down
to the anterior rectus fascia. If a cutaneous component is required, the
skin paddle should be designed to permit the appropriate closure of the
abdominal skin without tension. In the case of the SIEA flap, the vein is
often found 0 to 8 cm from the midline and relatively superficial, so it is
important to avoid injury during the initial incision; the artery is often
slightly deeper and more lateral.26 The tissue is elevated superficial to
the anterior rectus fascia if starting in the midline (eg, with a VRAM) or
the external oblique fascia (eg, with a TRAM, DIEP, or SIEA flap).
DIEPs are identified coursing through anterior rectus fascia into the
tissue. These are ligated if a SIEA flap is performed (once it is
confirmed that the superficial system is adequate). If a muscle flap is
used, the borders of the rectus muscle are identified, and a portion of
the overlying anterior fascia is resected with the muscle. The amount of
fascia can be minimized if desired by designing the lateral fascial
incision as close to the DIEPs as possible. The deep inferior epigastric
vessels are identified lateral to the muscle and traced down to their
origin. In the case of DIEP flap, the selected perforators are dissected
away from the muscle, allowing the tissue to be harvested without the
muscle.
Donor Site Considerations
The most important potential adverse effects are abdominal weakness,
bulge, and hernia. This risk is the highest with muscle or myocutaneous
flaps and lowest with SIEA flap, which does not require any incision of
the rectus abdominis muscle or fascia.
24,25
In some cases, surgeons
may choose to reinforce the fascia with mesh to diminish this risk.
Rectus muscle or fascial harvest may also require formal abdominal
wall reconstruction. Increased intra-abdominal pressures from closures
https://t.me/med1917
following flap harvest may also potentially negatively affect pulmonary
function.
Latissimus Dorsi Muscle and Thoracodorsal Artery
Perforator Flaps
The latissimus dorsi is a triangular-shaped muscle that originates on
the iliac crest and thoracolumbar fascia and inserts into the humerus.
Mathes and Nahai classified it as a type V muscle, with a dominant
blood supply from the thoracodorsal artery and secondary segmental
circulation from the posterior intercostal perforators.5 The muscle can
be harvested alone or with a skin paddle, which can be oriented
anywhere along the broad muscle depending on the size and shape of
the defect but is often designed along resting skin lines for easy
closure. If a large cutaneous component is required, skin grafts may be
used for donor site coverage. If only skin and soft tissue are only
needed, a thoracodorsal artery perforator (TDAP) flap may be raised
on one or more perforators. Using fresh cadavers, Heitmann et al
identified 64 musculocutaneous perforators larger than 0.5 mm, slightly
more than half of which originated from the descending branch and the
remainder of which from the transverse branch of the thoracodorsal
artery.
27
Indications
The latissimus dorsi muscle is the largest muscle in the body, so it is
particularly useful for reconstruction of broad wounds. It can even be
combined with serratus, scapular, or parascapular flaps to extend its
size. It is also beneficial because its thinness permits it to be easily
draped over irregular wounds. In addition, it can be utilized as a
functional muscle if reinnervated with the thoracodorsal nerve. The
reach of a pedicled latissimus flap is variable depending on the
patient’s body habitus, but it is a common choice for coverage in the
chest or neck. It is particularly useful for breast reconstruction with or
without an implant. In addition, the latissimus dorsi or TDAP flap can be
utilized virtually anywhere as a free flap. Furthermore, because the
subscapular system from which the thoracodorsal artery originates has
a relatively consistent anatomy, it is also possible to design TDAP flaps
https://t.me/med1917
with multiple skin paddles or chimeric flaps with separate cutaneous,
muscle, and bony components.
Surgical Technique
Muscle or myocutaneous flap harvest typically requires the patient to
be placed in lateral decubitus or prone position if bilateral flaps are
required. The ipsilateral arm should be prepped in anticipation of free
movement around the surgical field. The incision is typically designed
from the axilla, or the posterior axillary fold then extended inferiorly and
medially over the muscle. Alternatively, an inferomedial incision with or
without a skin paddle can be designed with a separate incision near the
axilla to minimize scar burden. Skin and soft-tissue flaps are raised
inferior and superior to the incision to expose the muscle and its fascia.
The muscle is then elevated and dissected from its superior, medial,
and inferior attachments with care not to include the serratus muscle
laterally if not required. The serratus muscle is most easily identified at
the superior edge of the latissimus dorsi muscle at the inferior angle of
the scapula. The thoracodorsal vessels are found along the deep
surface of the muscle near the thoracodorsal nerve. The serratus
branch and the humeral insertion may be divided to achieve adequate
pedicle length and proximal dissection.
If muscle is not required, the TDAP flap can be designed based on
perforators either from the descending or transverse branch of the
thoracodorsal artery. Perforators from the descending branch are
typically identified 8 to 10 cm inferior to the posterior axillary fold and 2
to 4 cm posterior to the free lateral edge of the latissimus dorsi muscle.
There are also perforators anterior to the free muscle edge that arise
directly from the thoracodorsal artery or other source vessels that may
be identified using handheld Doppler. TDAP harvest is generally
performed in the lateral decubitus position but may potentially be
performed supine in some cases depending on flap design.
Donor Site Considerations
The latissimus dorsi adducts, extends, and medially rotates the
humerus, in addition to securing the tip of the scapula against the chest
wall, but is generally considered expendable if the shoulder girdle
muscles are preserved. Patients may experience impaired shoulder
https://t.me/med1917
motion, strength, and function, but studies demonstrate that these
symptoms typically improve by 12 months postoperatively.28 Scarring
from either the muscle, myocutaneous, or TDAP flap can be favorable
as it can be designed to be hidden with clothing, even in a bathing suit
in some cases.
Radial Forearm Flap
Previously known as the Chinese flap because of the country where it
was first performed, the radial forearm flap was first described by Yang
et al as a reliable fasciocutaneous flap.29 As its name suggests, it is
based on perforators of the radial artery with drainage from its
associated vena comitans, although the cephalic vein may also be
used for venous outflow. If required, the flap can include a portion of
the radius for bony reconstruction, the lateral antebrachial cutaneous
nerve for neurotization, or the palmaris longus tendon for functional
purposes. It can also be harvested as just fascia-only if skin is not
required.
Indications
The radial forearm flap is useful for the reconstruction of small-tomoderate defects requiring thin and pliable tissue. As such, the radial
forearm free flap (RFFF) is considered a workhorse free flap for head
and neck reconstruction. Its thinness makes it well suited for intraoral
defects, cutaneous defects of the scalp and face, and pharyngeal
reconstruction. It can also be made into a tube, making it the most
common choice for phalloplasty.30 In addition, the reverse radial
forearm flap can be a good option for defects along the dorsal or volar
hand.
31
Surgical Technique
A tourniquet is generally used to aid flap elevation. The skin paddle
should be designed over the radial vessels with a shift laterally if there
is a plan to include the cephalic vein. The distal border is typically
incised first, and the radial vessels are identified between the muscle
bellies of the brachioradialis and flexor carpi radialis muscles. The
vessels are ligated distally, and the remainder of the incisions are made
with subsequent elevation of the flap distally to proximally with care to
https://t.me/med1917
protect the sensory branches of the radial nerve. It is important to
preserve the fascial covering over the tendons to maximize subsequent
skin graft take for donor site coverage. Once the skin paddle is
elevated, the vessels are dissected proximally to adequate vessel
diameter and pedicle length. After the tourniquet is released, it is
important to assess not only the viability of the flap but also the
perfusion of the hand. If needed, reconstruction of the radial artery can
be performed with a reversed vein graft.
Donor Site Considerations
Prior to performing a radial forearm flap, it is necessary to perform an
Allen test to elucidate the continuity of the palmar arch and determine if
radial artery insufficiency would result in inadequate blood flow to the
hand. It is also important to document the patient’s handedness, as it is
preferable to harvest the flap from the patient’s nondominant arm to
minimize the effects of any potential resultant functional deficits. The
overall donor site morbidity is low, but not negligible as patients may
experience cold intolerance, decreased range of motion, and
decreased grip strength.32 Furthermore, scarring in the donor site,
which typically requires a skin graft to close, is a notable consideration,
as it is not in an area that is easily hidden.
Gracilis and Profunda Artery Perforator Flaps
The gracilis is a Mathes and Nahai type II muscle with a dominant
blood supply from the descending branch of the medial circumflex
femoral artery via the profunda femoris artery.5 It runs in the medial
thigh, originating from the pubic symphysis, inferior pubic ramus, and
ischium and inserting into the medial condyle of the knee. It can be
harvested as a pedicled or free muscle or myocutaneous flap with the
skin paddle designed transversely (transverse upper gracilis [TUG]
flap) or diagonally (diagonal upper gracilis [DUG] flap).33 The obturator
nerve may also be included for functional muscle transfer. If muscle is
not required, a fasciocutaneous flap may be harvested based on the
posterior thigh profunda femoris perforators (profunda artery perforator
[PAP] flap).
34
Indications
https://t.me/med1917
Given their location, pedicled upper thigh flaps are frequently used for
perineal reconstruction although abdominal-based flaps are typically
used if greater dead space obliteration is required. The pedicled
posteriorly based PAP flap may also be useful for pressure sore
reconstruction. These upper thigh flaps are particularly valuable as free
flaps. Free functional gracilis transfer is commonly used for facial
reanimation and restoration of upper extremity range of motion, such
as for elbow flexion after brachial plexus injury. Nonfunctional free
gracilis transfer can be utilized for a variety of defects throughout the
body, but the TUG, DUG, and PAP flaps are most commonly described
as alternative flaps for autologous breast reconstruction.
Surgical Technique
Patients are typically placed in “frog leg” position for adequate access
to the medial and posterior thigh. The gracilis muscle is generally 2 to
3 cm posterior to the adductor longus, which should be palpable in the
frog leg position. If required, the skin paddle is designed with the
superior incision in the groin and buttock crease for the TUG flap or
along Langer lines with the anterior border oriented along the
prominence of the adductor longus for the DUG flap.33 The skin island
may be elevated by traveling posteriorly in the subfascial plane to
identify the intermuscular septum between the adductor longus and
gracilis, within which the pedicle can be identified approximately 10 cm
distal to the ischium and followed. If a skin paddle is not required, the
scar burden may be minimized by using a small incision distally to
disinsert the gracilis.
The PAP flap was first described with a transverse skin paddle
marked along the posterior thigh 1 cm below the gluteal crease, but
modifications have described a vertically based and diagonally based
skin paddles, the latter of which may be preferred for breast
reconstruction.
34,35
Perforators are identified within 8 cm of the gluteal
crease, between adductor magnus and semitendinosus. These
perforators typically have a short intramuscular course through the
adductor magnus that requires dissection for harvest of the vessels at
the origin.
Donor Site Considerations
https://t.me/med1917
Соседние файлы в папке Библиотека им академика М.И. Перельмана