Latissimus dorsi flapGnter Germann and Markus
hlbauerIntroductionThe latissimus dorsi flap was introduced by
Tansini in 1906for the coverage of extensive mastectomy defects.
Subsequentlyforgotten, it was re-described by Olivari in 1976for
the coverage of large radiation ulcers of the chest wall.Boswick
(1978) adopted Olivaris idea and developed alatissimus island flap
for breast reconstruction. A furtherdevelopment, together with the
technical progress of microsurgery,was its use as a free
musculocutaneous flap.The latissimus dorsi flap, either as pedicled
or as microvascularfree tissue transfer, is one of the most
commonlyused flaps in reconstructive surgery, with large vessel
diametersand a long reliable pedicle. Its size and versatility
makeit an extraordinary graft that has been a workhorse in
reconstructivesurgery for more than two decades.It can be elevated
as a muscle, a musculocutaneous or anosteomyocutaneous flap. As a
composite graft including variableamounts of muscle, skin, and
subcutaneous tissue, itcan be used in any variety for
reconstruction in every area ofthe body. The harvested flap can be
as large as 20 35 cm,but numerous combinations with other flaps
nourishedby the subscapular system are possible to
simultaneouslyreconstruct more complex defects with several flaps,
basedon a single pedicle.Regional anatomy (Figure 23.1)The
latissimus dorsi muscle is the mirror image of the pectoralismajor
muscle. Its aponeurotic origin arises froma broad front, extending
from the seventh and lower thoracicvertebrae spine, the lumbar and
sacral spine processes,to the posterior and middle outer rim of the
iliac crest viathe thoracodorsal fascia. The superior portion of
the medialaspect of the latissimus muscle is covered by the
trapeziusmuscle; otherwise, the latissimus muscle is superficial
toall other muscles in the back. The latissimus muscle coversa
portion of the paraspinal muscle and the majority ofthe serratus
anterior muscle. In the middle portion there isa rather tight
attachment to the 10th, 11th, and 12th ribsand to the fibers that
interdigitate with fibers of the serratusanterior muscles.
Superiorly it is adherent to the inferiorborder of the teres major
muscle. Its triangular large and flatmuscle belly converges into a
flat, broad tendon. Near itsinsertion into the lesser tubercle and
the medial lip of theintertubercular groove of the humerus (Figure
23.2) it spirals180 around and travels anterior to the tendon of
theteres major muscle.There are numerous important functions of the
latissimusdorsi muscle. Primarily it acts as an extender,
adductor,and medial rotator of the humerus. It holds the
inferiorangle of the scapula against the chest wall and stabilizes
andelevates the pelvis when bringing the lower extremity forward.It
aids in coughing and, unduplicated by other muscles,it pulls the
arm posteriorly, directly behind the back,a motion that is best
described by the terminal action ofpushing off with a ski
pole.Arterial anatomy of the region (see Figures 23.1, 23.2)The
latissmus dorsi muscle is a class V muscle with a dominantpedicle
(thoracodorsal artery and vein) and secondaryblood supply from the
posterior intercostal perforators.The thoracodorsal artery arises
from the subscapular arteryand divides within 23 cm of its origin
from the third segmentof the axillary artery, into the
thoracodorsal and circumflexscapular arteries (see Figure 23.2).
The subscapularartery may arise from the axillary artery as a
commontrunk with the posterior circumflex humeral in about 30%of
cases. In approximately 3% of patients, the circumflexscapular
artery arises directly from the axillary artery; inalmost 1000
clinical cases, we have seen this to be true forthe thoracodorsal
artery in approximately 2%. The thoracodorsalartery, shortly before
entering the latissimus dorsimuscle, may send up to three branches
to the serratus anterior;these branches are present in the majority
(more than75%) of cases. They will be relevant later when
harvestingthe serratus flap as part of a chimeric unit. When
present,these vessels are 12 mm in diameter and are usually
eachaccompanied by two veins. This serratus anterior collateralmay
become significant in supplying blood to the latissimusdorsi muscle
when the thoracodorsal artery has beendivided during axillary
dissection in mastectomy.A further but less significant possible
source of collateralsupply to the latissimus dorsi comes from the
circumflexscapular and dorsal scapular vessels reaching the teres
major.Before the take-off to the branch to the serratus muscle,the
angular branch supplying the tip of the scapula canpotentially
serve as a vascular pedicle for a bony segmentof the scapula. The
emergence of the vascular bundle in thefibrofatty tissue is
identified, with care taken not to dividethe small, easily observed
branches to the bone over thescapular border.Venous anatomy of the
regionThe subscapular vein is large in caliber (9 mm) and has
anaverage length of 2 cm. It courses in the middle of the
axillaparallel and inferior to the edge of the latissimus dorsi
muscleto the axillary vein.The circumflex scapular vein usually
drains into the subscapularvein, but can also drain directly into
the axillaryvein. The circumflex scapular vein is usually formed
immediatelybefore entering the subscapular vein by two
concomitantveins, both with a caliber that allows
microvascularanastomosis. Concomitant veins running parallel to the
arteriesdrain the latissimus dorsi muscle. Towards the inferiorend
of the muscle insertion, several venous arcades are foundthat are
connected to the serratus anterior muscle and mustbe divided when
the flap is elevated.The thoracodorsal veins are predominantly
present inpairs up to the branching of the circumflex scapular
vein,but then unite to form a single accompanying vein.Nerves in
the regionThe thoracodorsal nerve accompanies the pedicle
lateroinferiorlyand divides into a lateral and a medial
branch.Closely intimate with the thoracodorsal bundle, it mustoften
be divided during flap harvest.The long thoracic nerve is tightly
connected to the serratusfascia in its lower part, whereas its
upper part is onlyloosely attached when passing through the
axillary space.Cutaneous branches of the intercostal nerves and
lateralbranches of the posterior rami provide sensibility of the
lateraltrunk.Flap anatomyArterial supply of the flap (see Figures
23.1, 23.2)The latissimus dorsi muscle has a dual blood supply
fromthe subscapular artery and the posterior paraspinous
perforators.Both circulatory systems are diffusely interconnectedso
that the muscle can survive in its entirety if either pedicleis
interrupted.Dominant: thoracodorsal artery, a branch of
thesubscapular arteryLength: 8.5 cm (range 6.512 cm)Diameter: 3 mm
(range 24 mm)The thoracodorsal artery courses from the axilla along
theanterior border of the latissimus dorsi muscle, enters themuscle
from underneath, and spreads into two or threemajor branches at the
undersurface of the muscle. Anatomicvariations can be seen where
the thoracodorsal artery canarise directly from the axillary artery
or even from the lateralthoracic artery in 35% of patients.Heitmann
et al revisited the latissimus dorsi muscle toprovide a
comprehensive synopsis of its anatomy. The neurovascularhilus was
found on the deep surface of the latissimusdorsi muscle
approximately 4 cm distal to the inferiorscapular border and 2.5 cm
lateral to the medial border ofthe latissimus muscle. At that point
there was a constantbifurcation into a horizontal (medial or
transvere) branchand a descending (lateral or vertical) branch, but
there areinterconnections between the horizontal and
descending/lateral branches.In more than 90% of cases the
thoracodorsal arterybifurcates into the medial and the slightly
larger lateralbranch. The lateral branch characteristically
parallels thelateral border of the muscle, running approximally 2.5
cmfrom its edge. The upper or medial branch separates fromit at an
angle of about 45 and parallels the upper muscleborder. Within the
muscle both branches divide into lesserbranches which run medially
and anastomose with perforatorsfrom intercostals and lumbar
arteries. A very significantfeature of these anastomoses is their
large diameter.In the remaining cases the neurovascular tree splits
intothree or four major branches. Both branching patterns supplythe
muscle with long, parallel neurovascular brancheswhich run in the
fascia between bundles of muscle fibersand thereby enable the
muscle to be split into independentvascularized innervated
units.Cutaneous perforator vessels could be traced to the
thoracodorsalartery and had a caliber greater than 0.5 mm.They were
always found in proximity to the horizontal orthe lateral branch.
All thoracodorsal cutaneous perforatorsoriginated within a distance
of 8 cm distal to the neurovascularhilus.The thoracodorsal artery
supplies predominantly the latissimusdorsi muscle but also gives
branches to the serratusanterior muscle, the axillary skin, the
subscapular and teresmajor muscles.The thoracodorsal artery gives
off one to three branchesof about 1 mm diameter to the serratus
anterior which penetratethe muscle in its midportion along the
course of thelong thoracic nerve. Reversal of flow may take place
in thesevessels and also in vessels from teres major in the
paratenonaround the insertion and perhaps in other direct
vesselsentering from axillary and intercostal vessels.The
thoracodorsal artery also gives off a cutaneousbranch in about 75%
of cases, before it continues on topenetrate and supply the
latissimus dorsi. The cutaneousbranch arises between 0.5 and 2 cm
beyond the bifurcationof the subscapular artery.The subscapular
artery arises in general as a branch ofthe third portion of the
axillary artery. Its average externaldiameter at its origin at the
axillary artery is about 6 mmand its average length to the origin
of the circumflex scapularartery is about 2.2 mm.Usually the
circumflex scapular artery (average length4 cm, average diameter 4
mm) is found to be the first branchof the subscapular artery but in
about 3% the circumflexscapular artery is a direct branch of the
axillary artery.The second major branch of the subscapular artery
is thethoracodorsal artery.Minor: perforating posterior branch of
the posteriorintercostal arteriesLength: 2 cm (range 1.52.5
cm)Diameter: 1.5 mm (range 12.1 mm)The ninth, 10th, and 11th
intercostal vessels provide the threelargest medial dorsal branches
and have been the major vascularpedicles for the reverse latissimus
dorsi musculocutaneousflap. In contrast, the lateral branches
initially were onlyoccasionally mentioned as a source of pedicled
flaps, but laterthey were also used as donor vessels for the
reverse latissimusdorsi flap. Because of their short pedicle, both
the medialand lateral dorsal branches have been confined to their
useas pedicled flaps. Even if the vascular pedicle is of
sufficientlength for a free flap, the difficult and harmful
preparation ofthe vessels through the thick package of paraspinous
musclesdown to the source vessels is justified only
exceptionally.These vessels predominantly supply the distal part of
thelatissimus dorsi muscle. They are found in two rows as
segmentalvessels 510 cm from the dorsal midline. There areusually
four to five vessels in each segmental row. The lateralrow derives
its blood supply from branches of the posteriorintercostal artery
and the medial row derives its bloodsupply from the lumbar
artery.Venous drainage of the flapAccompanying veins follow the
arteries.Primary: thoracodorsal veinLength: 9 cm (range 7.510
cm)Diameter: 3.5 mm (range 25 mm)Usually the thoracodorsal vein
originates from the subscapularvein. Anatomic variations in venous
anatomy arepresent in 35%. Most often the thoracodorsal vein is
doubledor originates direct from axillary vein.Usually the
subscapular vein and artery arise adjacentto each other but in
about 10% of cases the axillary arteryarises proximal to the
subscapular vein. The length of thesubscapular vein averages 2 cm,
with an average diameter of9 mm. The circumflex scapular vein can
arise directly fromthe axillary vein; usually two veins are found,
both with adiameter that allows
microanastomosis.SecondaryConcomitant veins, running with the
perforating arterialvessels, provide secondary venous
drainage.Length: 2 cm (range 1.52.5 cm)Diameter: 2 mm (range 1.12.7
mm)The venous drainage of the muscle parallels the arterial
supplybut the presence of venous valves has important
implicationsfor flap design. The lower and medial parts of the
muscle preferentiallydrain through the intercostals and lumbar
venoussystem and not via the thoracodorsal system. Valves withinthe
vein ensure this direction of flow. Also, the circumflexscapular
vein can provide secondary drainage of the flap. Incases where a
pedicled latissimus flap is performed based onretrograde flow from
the circumflex scapular artery, the veincan provide adequate
drainage to the flap.Whereas in the arteries reversal of flow can
easily takeplace and blood can reach the extreme parts of the
muscle,on the venous side there are problems in draining
theinferior end of the muscle into the thoracodorsal system.The
result is that the muscle-only flap suffers venous compromisein its
lower part and any areas that appear suspectafter reperfusing a
free flap should be excised as experiencehas shown that these
areas, which initially have an arterialinflow but which ooze dark
deoxygenated blood, do notsurvive. By contrast, the
musculocutaneous flap fares betterin its distal part, perhaps
because venous blood from themuscle can find an additional pathway
of return throughthe subcutaneous venous network.Flap innervation
(see Figure 23.1; see also Figure 21.1)Sensory innervationThe
posterior branches of the lateral cutaneous branches ofthe
intercostal nerves provide cutaneous sensibility laterally,and
lateral branches of the posterior rami (VI through XII)posteriorly.
Usually these branches are not used to reinnervatethe flap, but in
the special case when a reverse pedicledflap is performed based on
the posterior intercostal vessels,its sensory innervation can be
preserved and so the sensoryinnervation can be maintained.Motor
innervationThe thoracodorsal nerve arises from the posterior cord
ofthe brachial plexus and travels latero-inferiorly behind
theaxillary artery and vein. It is usually located 3 cm medial
tothe origin of the subscapular artery in the axilla. The
thoracodorsalnerve accompanies the vascular pedicle moreclosely,
approaching the entrance of the neurovascular bundle,and it is
sometimes difficult to preserve the nerve duringelevation of the
flap. Even if only a small portion of muscleis included, the entire
muscle is denervated. The nervedivides into lateral and medial
branches approximately1.3 cm proximal to the neurovascular hilus
and each branchruns with its vascular counterpart.Some authors have
described an intramuscular dissectionof the nerve that allows for
preservation of it. So ifthe intention is to split the muscle and
retain half of it onthe chest with an intact nerve supply, then the
dissection isobviously more complicated. The vascular basis for
splittingthe flap is the known bifurcation of the
thoracodorsalartery within the muscle which enables either the
superiorhorizontal part of the muscle or the anterior vertical part
tobe harvested on the thoracodorsal pedicle. In this situationthe
part of the muscle left on the chest is detached from
thethoracodorsal pedicle and receives its blood supply fromthe
intercostal perforators. If this part of the muscle is leftin
continuity with the tendon of insertion and its innervationis
preserved, then some function should be retained init. The
bifurcation of the thoracodorsal artery is on average8.7 cm from
the point where the subscapular artery arisesfrom the axillary
artery.Proprioceptive nerve fibers accompany motor fascicles ofthe
thoracodorsal nerve. This may be the reason why somestudies report
deep sensation of a transferred latissimusdorsi flap up to 18
months after coaptation of the thoracodorsalnerve to a sensory
recipient nerve.Flap componentsThe latissimus dorsi flap can be
raised as a muscle, a musculocutaneous,an osteomusculocutaneous, or
even a perforatorflap (TDAP). The skin is nourished via the fascia
and theperforator vessels, which therefore must be taken with
themuscle in musculocutaneous flaps.Combinations and extensions are
possible with anycomponent from the subscapular system (i.e. bone,
skin,fascia, muscle). On the same pedicle it can be elevated
withthe serratus fascia or the serratus muscle, the accompanyingrib
or part of the scapula, or with a scapular or parascapularflap. In
this way it is possible to harvest multicomponentflaps to
simultaneously reconstruct complex defects withseveral flaps based
on a single pedicle.Advantagesl Latissimus dorsi dissection is
rapid, easy, and safebecause of the reliable anatomy of the
thoracodorsaland subscapular vessels.l Microvascular transfer is
facilitated by the long pedicleand large caliber of the vessels.
The robust viability ofthis large muscle flap constitutes its major
commendingfeature.l A skin island can be orientated vertically,
obliquely ortransversely as desired or required by the defect.l The
latissimus dorsi flap is the largest single flap that itis possible
to harvest in the body. It can be tailored toalmost any size and
shape. The flap can extend from theaxilla to almost the iliac
crest. Elevating the latissimusdorsi flap so far distal will result
in an extremely longvascular pedicle, making the flap especially
suitable forlarge skin defects or anastomotic sites remote from
thedefect.l As a pedicled flap, it is certainly one of the most
versatileflaps for reconstructive problems of the chest wall and
theupper arm. The pedicled muscle flap alone will also
supplycoverage for massive defects of the head and neck areaas well
as the shoulder.l Where large areas of a thinner flap coverage
arerequired, the muscle alone can be transferred microsurgicallyand
then skin grafted to avoid excessive bulk atthe recipient area, and
to avoid a large secondary skindefect in the donor area.l The
musculocutaneous latissimus flap may be advantageousin providing
bulk for the correction of contourdefects.Numerous combinations are
possible. Combined (chimeric)flaps with other components from the
subscapularsystem can be designed, vascularized bone can be
harvestedas rib grafts with the latissimus or on a common pedicle
fromthe scapula, fascia can be added from the serratus muscle.The
thoracodorsal nerve can be included so that the musclecan be
reinnervated for restoration of motor function.If the latissimus
dorsi flap is harvested correctly, severalflaps such as the
scapular flap or the serratus muscle/fasciaflap are still possible,
although with smaller vessel diameters.Overall, the usefulness of
this remarkable flap far outweighsits recognized
disadvantages.Disadvantagesl This flap, especially the
musculocutaneous type, is generallybulky, depending on the general
physical constitutionof the patient. Exact intramuscular dissection
withtailoring of the flap to the defect size can
significantlydecrease the amount of muscle harvested. Even
thoughthe muscle atrophies to some degree, skin islands
inmusculocutaneous flaps are usually also bulky andrequire
secondary thinning and contour correction forsatisfactory aesthetic
results.l Surprisingly, the functional deficit of shoulder and
armfunction from loss of the latissimus dorsi muscle is estimatedto
average approximately 7% in most individuals.If all the other
muscles of the shoulder girdle areintact, the loss of the
latissimus dorsi muscular functionis rarely noticeable in normal
activities. Occasionally,the harvest of this muscle will result in
some winging ofthe scapula, even though the serratus anterior
muscle isintact. It can also compromise the motion of
posteriorpush, an important function in skiing, where the handis
pulling the body weight forward. Also loss of thelatissimus in
paraplegics may seriously weaken upperextremity function like
crutch-walking or bed-to-wheelchairtransfer. Similarly in patients
with poliomyelitisor other neuromuscular diseases, loss of the
latissimusdorsi muscle may seriously weaken pelvic stability.l
Other disadvantages are directly related to donorsite
complications. Pains at the donor site and seromaformations are
occasionally seen. Most of thesesymptoms disappear over time, and
persistentcomplaints are rare.Preoperative preparationNo
preoperative vessel identification is necessary. In cases
ofprevious axilla dissection or radiation, muscle function hasto be
evaluated preoperatively. If muscle function is intact,the vessels
are usually not violated. If the muscle functiondoes not seem to be
good, further studies such as the Dopplerprobe can be performed to
see if the muscle is viableand can be used for wound coverage.A
donor site for possible skin grafting is also preppedand draped.
Preoperative antibiotics are not given routinelyand the decision is
based on the recipient site and the conditionof the patient.Flap
designAnatomic landmarks (Figure 23.3)The margins of the latissimus
dorsi muscle extend fromthe tip of the scapula to the midline of
the back posteriorlyand with its fascial extension to the iliac
crest inferiorly.The anterior border of the muscle passes on an
oblique linefrom the midpoint of the iliac crest to the axilla.
This prominentborder forms the posterior axillary fold together
withthe subscapular and the teres major muscles.General thoughts
about flap designThe design of the latissimus dorsi flap can be
varied accordingto the requirements for skin or muscle. Therefore
thelocation and proportion of the skin island must be
exactlydetermined during preoperative planning. If more skin
thanmuscle is needed, then the skin island should be basedtowards
the anterior edge of the muscle.Several areas of skin can be raised
separately on the samemuscle flap, so that many reconstruction
possibilities areavailable. The anterior edge of the muscle should
always beincluded because the greatest number of perforating
vesselssupplying the skin is found there.Special
considerationsBreast reconstructionFor breast reconstruction, the
island over the upper free muscleborder is preferable, as the
secondary defect, when closed,leaves a transverse scar that is
easily concealed by a brassiere.Head and neck reconstructionFor
head and neck reconstruction, a skin island along theanterolateral
margin of the muscle is necessary because thetransverse island will
not reach. Elevation of a muscle flapmay be done through either
incision.Soft tissue defect of the lower extremity witha bone
defectWhen raising the flap with bone from the scapula there
arevariations in the anatomy to be considered. The generalscheme is
shown with the angular branch supplying thelower pole and the
circumflex scapular artery the middleand upper thirds of the
lateral border. The angular brancharises directly from the
thoracodorsal artery just proximal tothe origin of the branch of
serratus.In a small percentage of patients, the latissimus
musclemay play a significant role in raising the pelvic bone
whilewalking. In patients with spinal cord injuries affecting
thisarea, the dimensions and thickness of the muscle may bequite
small.The latissimus dorsi muscle can be carried on the
highestbranch of the circumflex scapular artery, even if the
thoracodorsalartery is sacrificed. This smaller vessel
usuallyprovides a reliable blood supply for the muscle with
theexception of the most distal aspects.Differences in design when
performing the flapas pedicled or freePedicled flapIn planning the
pedicled flap, Chandra uses the horizontalcontinuation of a line
drawn through the nipples (with thearm by the side) to surface mark
the base of the flap. Thelong axis of the flap then has its center
line 1 cm anteriorand parallel to the edge of the latissimus dorsi.
The largestflap described by Chandra was 7 20 cm and all donorsites
were capable of direct closure.Flap dimensionsMuscle
dimensionsLength: 35 cm (range 2142 cm)Width: 20 cm (range 1426
cm)Thickness: 1.5 cm (range 0.54.5 cm)The average dimensions are 46
cm more in male patientsthan in female patients.Skin island
dimensionsLength: 18 cm (range up to 35 cm)Width: 7 cm (range up to
20 cm)Maximum to close primarily: 89 cmThickness: 2.5 cm (range 15
cm)The latissimus dorsi flap can be tailored to almost any sizewith
a maximum dimension of 20 35 cm. Primary closureof the donor site
can be achieved when the width isless than 89 cm.Bone
dimensionsLength: 5 cm (range 1.58 cm)Width: 2 cm (range 15
cm)Thickness: 2 cm (range 13 cm)Flap markings (Figure 23.4)Design
of over- and underlying structures that can beincluded with the
flap:1 The scapular flap2 The parascapular flap3 The serratus
fascia flap4 The serratus anterior muscle flap5 The lateral edge
and also the inferior edge of scapula are particularlywell suited
as a donor site for a segment of bone.Markings of the flap:6 The
transverse skin island of latissimus dorsi myocutaneousflap7 The
vertical skin island of latissimus dorsi myocutaneousflap8 For
breast reconstruction the island should always beoriented at right
angles to the scar on the anterior chestwall. Thus, a vertical skin
island is needed for a transversescar, while a more transverse
island is needed for a verticalscar.Before the operation the
anterior edge of the latissimusdorsi muscle has to be identified.
It can be seen and felteasily when the patients hands are placed on
the hips. Theanterior muscle border and tip of the scapula are
marked tooutline flap borders.Then a line is drawn from the middle
of the iliac crest tothe posterior axillary fold. On this line the
entry of the pedicleinto the muscle 1012 cm below the axilla is
marked.After the size of the skin island has been determined, itis
drawn on the skin with the help of a template. Careshould be taken
to position the skin island so that a sufficientnumber of
perforator vessels is included. Thereforesome surgeons use the
Doppler probe for design of the skinisland. This will eliminate any
concern about perfusion ofthe flap and the skin island. The Doppler
is particularly usefulwhen a small skin island is planned as it
becomes morecritical to make sure that there is at least one skin
vessel supplyingthe skin island.Patient positioningMost surgeons
would agree that a lateral decubitus positionis ideal for flap
harvest, although it is possible with thepatient in a prone or even
a supine position with a 45 lateraltilt. The arm is abducted to 90,
the elbow also flexed90. More abduction may stretch the brachial
plexus. Thearm is prepped sterile so that a limited mobility is
permitted.Wrapping with cotton bandages must also protect theulnar
nerve at the elbow. This position allows excellentaccess to the
vascular pedicle as well as the chest wall in caseof a pedicled
transfer.In cases of a free transfer to the lower extremity, the
flapis usually harvested from the contralateral side. The
ipsilateralleg is maximally flexed in the hip to allow a
two-teamapproach to the injured lower leg.Also in cases of a free
transfer to the upper extremity, theflap is usually harvested from
the contralateral side.Anesthetic considerationsGeneral anesthesia
is needed to harvest the latissimus dorsiflap.Technique of flap
harvest (Figure 23.5)The axis of the flap lies about 2 cm posterior
to the anterioredge of the latissimus dorsi muscle. The skin island
can beanterior to this edge of the muscle. Ideally the flap is
basedon the anterior edge of the muscle because of the
concentrationof perforating vessels (Figure 23.5A).The first
incision exposes the anterior edge of the latissimusdorsi muscle
between the axilla and the proximaledge of the flap. Then the
pedicle is easily found in the fattyconnective tissue medial to the
muscle and exposed up toits entry into the latissimus dorsi muscle
(Figure 23.5B).Once the pedicle is exposed, the skin island is
incisedaround its circumference and elevated anteriorly from
theserratus anterior muscle up to the ventral edge of the
latissimusdorsi. Next the latissimus dorsi muscle with itsoverlying
skin island is dissected bluntly from the serratusanterior muscle.
Caudally sometimes sharp dissection isneeded (Figure 23.5C).The
latissimus dorsi muscle is divided below and posteriorlybut remains
still attached above. In this area the relativelysmall muscle is
dissected free, protecting the pediclecarefully (Figure 23.5D).The
medial border of the muscle, which is always foundmore medially
than expected, should be identified by palpation.The incision
depends on the type of muscle harvestedand the type of
reconstruction planned. In breast reconstructionor musculocutaneous
flaps, the incision includesthe skin island and depends on the
position of the skinisland.The surgeon is positioned on either the
anterior orthe posterior aspect of the patient. The anterior
approachfacilitates access to the axilla and the pedicle, the
posteriorapproach permits a better overview of the dorsal
perforators.In the standard harvesting technique, an incision is
madefrom the posterior axillary fold postero-inferiorly towardsthe
iliac crest, 35 cm posterior to the medial border of themuscle. The
length of the incision correlates only roughlywith the size of the
muscle flap required. The entire musclecan be raised from a rather
short incision. We usuallyinclude a monitoring island, placed in
the course ofthe incision. Generally, the musculocutaneous
perforatorsfrom the latissimus dorsi are more numerous over
theproximal two-thirds of the muscle. Care should be taken tomake
this skin island large enough to allow reliable
clinicalmonitoring.The muscle is then separated from the serratus
fibers andthe medial border is followed cephalad. The pedicle
shouldbe identified first. The course of the pedicle is relatively
constant,about 12 cm behind the anterior edge of the muscle.By
following this route, the serratus branch can be identifiedand
securely spared. The neurovascular bundle lies inthe fatty
connective tissue between the undersurface of themuscle and the
chest wall. The pedicle is dissected towardsthe axilla. Minor
branches of the pedicle are clipped orcoagulated with a bipolar
coagulation at a location remotefrom the pedicle.The circumflex
scapular artery is left intact for possiblefuture use. Constant
large perforator vessels at the tip of thescapula are ligated. The
dissection of the pedicle is finalizedby splitting the fascial leaf
that separates the latissimus fromthe teres muscles from dorsal.
When ligating the branch tothe scapula, care must be taken not to
confuse this arterywith the second branch to the muscle. The
tendinous insertionis left intact until the dissection is
completed.After the pedicle has been identified, dissection
proceedsalong the medial border distally. The skin island is
incisedcircumferentially and the latissimus dorsi muscle is
liftedfrom the serratus anterior muscle by blunt dissection.
Toprevent the skin from shearing off the muscle, some staysutures
are applied. Meticulous hemostasis is mandatoryduring the entire
dissection. Smaller branches are coagulated;larger perforators are
clipped or even ligated. Themuscle is then divided distally by
diathermy. Dissectionnow moves towards the spine. At any point in
dissection theflap can be tailored to its required
shape.Function-preserving harvesting techniques are technicallymore
challenging. Here the pedicle has to be separated fromthe
thoracodorsal nerve. The flap can only comprise thosesegments that
are supplied by the vascular pedicle after thenerve has also
divided into segmental branches (see Figures23.1423.19).Latissimus
muscle or myocutaneous flappedicled transfer for breast or chest
wallreconstructionIn pedicled flap transfer, a tunnel is made
across the apex ofthe axilla to pass the flap from the back to the
front of thechest or to the upper arm. Drains are inserted in the
back and,after donor site closure, the patient is turned to the
supineposition, where the flap is arranged in the desired
positionTechnical tips to optimize outcomes andavoid
complicationsEven in a pure muscle flap, a skin island should be
taken asa monitoring point. This is of special importance in
largetraining units with a high number of residents. Clinical
flapmonitoring is significantly easier and unnecessary flap
failureresulting from poor judgment of the muscle perfusioncan be
avoided.l Additional skin should be harvested and stored in
therefrigerator. When the skin island is taken off after 510days,
stored skin can be transplanted as a bedsideprocedure.
Alternatively the skin can be harvestedfrom the monitoring island
before it is removed.l Muscle flaps usually shrink over time so
that contouringis only required in approximately 50% of cases.
Almostall musculocutaneous flaps tend to sag so that manyneed
contouring or flap correction. In the case of functionalmuscle
transfers, readjusting muscle tension issometimes required.l In
breast reconstruction we strongly recommend overcorrectionof the
desired breast size by 1520% and identificationof the thoracodorsal
vessels at the beginning ofthe operation, to determine their
integrity, because manypatients have undergone axillary dissection
or irradiation.l The length and diameter of the pedicle can be
increasedby 2 cm for length and to 6 mm diameter by includingthe
subscapular artery.l Identify the thoracodorsal artery before
dividing the serratusbranch. It is easy to take the serratus muscle
withthe latissimus muscle in that area.Postoperative
careGeneralPostoperative nursing care in the first hours allows
recognitionof vascular complications. The classic picture of a
venousthrombosis is the blue flap. The phase of venous thrombosisis
marked by an increase in the number of petechiae on thesurface of
the skin. The longer the occlusion is present, themore they
increase, particularly at the edges of the transplant.The flap
becomes red, then purple, and finally blue.Arterial thrombosis is
rarer than venous thrombosis andarises during the first few hours
after the operation. The typicalsign of arterial thrombosis is that
the flap becomes white.This complication is easier to recognize in
myocutaneousthan muscle flaps. The signs of capillary filling are
absent:after local pressure is applied to the flap, the
appearancedoes not change. When the pressure is removed, the
capillaryfill is not visible, the white flap becomes patchy
andgray-blue, pale in the middle, and, after a few days,
necrotic.Vascular spasm is common during operation of the
leg.Normally the spasm resolves spontaneously, but if it persistsit
can cause ischemia. To avoid vascular spasm, warmthcan help. Cold
is a well-recognized cause of flap loss andshould be avoided. The
body temperature can be maintainedby using warm ambient
temperature, heated inspiredair, heated intravenous fluids, a
heated blanket, extremitywraps, and arctic body bags. Even the
fluids used to washthe surface of the skin should be
heated.Recipient siteThe suction drains are removed after 35 days,
or when theyaccumulate less than 50 ml of fluid in 24 hours. The
skinclips or sutures are left for at least 14 days. Mesh grafts
aredressed until the fifth day after operation, and thereafter
thedressings are changed every second day. After 10 days thewound
can usually be left without dressing. Depending onthe flaps healing
process, the patients stay in hospital willbe about 23 weeks.Donor
siteThe suction drains are removed after 35 days, or when
theyaccumulate less than 50 ml of fluid in 24 hours. The skinclips
or sutures are left for at least 14 days because of thetension.
Especially when the skin has been continuouslysutured, the sutures
should not be removed before this.Mesh grafts are dressed until the
fifth day after operation,and thereafter the dressings changed
every second day. After10 days the wound can usually be left
without dressings.If the donor site has been closed under great
tension, carefulexercise of the affected shoulder can be started on
thethird day, because limitation in movement quickly sets inowing
to protective posturing, and not only in older
patients.OutcomesLong-term outcomesDepending on correct indication,
excellent outcomes can beachieved using a pedicled or free
latissimus dorsi flap. Severaltechnical aspects of the
reconstruction technique intended toenhance the functional and
aesthetic outcome and/or reducecomplications are believed to
contribute to good results, asmentioned above.Untoward
outcomesComplications are those that are general and likely to
beseen with any muscle flap. These include planning
errors,technical intraoperative errors, and postoperative care
errors,all of which can contribute to flap failure.Flap design
requires a precise knowledge of the topographicanatomy of the
muscle. Failure to align the skin territorycorrectly over the
muscle will result in necrosis of theskin flap. Obesity,
inexperience in flap design, and narrowmuscles are common causes of
inaccurate flap design.The arc of rotation of the flap is limited
by the location ofthe vascular pedicle and length of the flap. In
thin patientsthe flap will reach much further. These factors have
to betaken into account in preoperative planning. Furthermore,the
orientation of the overlying skin on the muscle is less precisein
obese patients.Donor siteThe donor site itself does not create any
significant surfacedepression or any excessive prominence of the
ribs, but ifmore than 5 cm of the skin is carried with the muscle,
awidened scar can be expected. If a skin graft is required
forclosure of the donor site, the resulting contour deformitycan be
remarkably unattractive, and it is difficult to achieveaesthetic
closure of these donor sites, particularly in obesepatients.Loss of
function is not noticeable in normal individuals.In patients
requiring the use of crutches, the effect is noticeable.Removal of
the muscle can also affect pelvic stability inparaplegic patients.
Also winging of the scapula is present insome patients. To avoid
this, care must be taken not to damageinnervation to the serratus
anterior muscle.The donor site constitutes the biggest disadvantage
ofthis flap because of the high incidence of seroma formation,which
occurs even with adequate suction drainage. Theseseromas are
occasionally difficult to eradicate and can resultin the formation
of a bursa. If this happens, it is usuallypossible to collapse the
cavity with a Penrose drain. After46 weeks this becomes an
intractable problem, and itmay be necessary to abrade or excise the
two surfaces of thebursa to obtain healing.IntroductionThe rectus
abdominis muscle (RAM) flap and its variationsare some of the most
important flaps used in reconstructivesurgery. Its popularity is
explained by the location of its skinisland in the inferior abdomen
which results in a skin resectionsimilar to that of conventional
abdominoplasties, especiallyin women undergoing breast
reconstruction.The RAM flap was first described by Holmstron in
1979who based the flap on its inferior pedicle, the deep
inferiorepigastric artery (DIEA). The RAM flap gained
popularitywith the work of Hartrampf, with its utilization as a
pedicledflap based on its superior pedicle, the superior
epigastricartery, in breast reconstructions.With the objective of
reducing the sequelae resultingfrom harvesting it from the
abdominal wall, Koshima in1989 proposed its use with complete
preservation of the rectusmuscle and its innervation, a flap which
is now termedthe deep inferior epigastric artery perforator (DIEP)
flap.Currently, the DIEP is considered the gold standard in
breastreconstructions in which large flaps are required.Regional
anatomy (Figure 19.1)A thorough knowledge of the anatomy of the
abdominalwall can aid in harvesting different combinations of
tissues,based on different sources of blood supply, while
producingreliable reconstructions with minimal chances ofhernia
formation and aesthetically displeasing results at thedonor
site.The subcutaneous tissue of the abdominal wall is composedof
superficial and deep fat separated by the superficialfascia. This
superficial fascia itself has two layers: a superficiallayer called
Campers fascia which is difficult to visualizeduring flap
dissection, and a deep layer termed Scarpas fascia,which is
clinically visible during dissection of the flap.The rectus
abdominis is a thin and flat muscle whichoriginates from the
anterior aspect of the costal cartilages(sixth, seventh, and
eighth) and the xiphoid process. Itinserts on the pubic symphysis
and body. At its origin themuscle is 67 cm wide and at its
insertion it is approximately3 cm wide. Three tendinous
intersections are presentin the upper half of the muscle which are
attached to theanterior rectus sheath only, not the posterior
rectus sheath.The rectus muscle is covered anteriorly and
posteriorlyby the rectus sheath, which is composed of several
layersformed by contributions from the aponeurosis of theabdominal
wall muscles.Lateral to the rectus muscles, the abdominal wall
musclesfrom superficial to deep are the external oblique,internal
oblique, and transversus abdominis. The pyramidalismuscle is a
small triangular muscle which originatesfrom the pubic body below
the insertion of the rectus andinserts into the linea alba around
the umbilicus. The externaloblique is the most superficial layer of
the anterior rectussheath throughout. Above the arcuate line, the
internaloblique splits to form part of the anterior and posterior
rectussheath. Below the arcuate line, the internal oblique doesnot
split and travels below the external oblique to form thesecond
layer of the anterior rectus sheath.The external oblique muscle
originates from the lowereight ribs and inserts on the anterior
half of the crest ofthe iliac bone as well as the linea
semilunaris. This muscleis supplied by the 7th12th intercostal
nerves and receivesblood supply from the lateral cutaneous branches
of theinferior eight posterior intercostal arteries.The internal
oblique muscle originates from the lateralpart of the inguinal
ligament, the anterior part of theiliac crest and the posterior
aponeurosis of the transversusabdominis muscle. The insertion is on
the inferior border ofthe lower four ribs and on the rectus sheath.
It is suppliedby the ascending branch of the deep circumflex iliac
arteryand lateral branches of the deep inferior epigastric
artery.The internal oblique aponeurosis contributes to the
anteriorrectus sheath below the level of the ninth rib. From
thatpoint inferiorly to the level of the arcuate line, the
aponeurosisof the internal oblique splits and contributes to
boththe anterior and posterior rectus sheath. Below the
arcuateline, the aponeurosis of the internal oblique does not
splitand contributes to the anterior rectus sheath only.The
transversus abdominis muscle originates from theinner part of the
iliac crest, lateral part of the inguinal ligament,the lower six
costal cartilages, and the transverseprocesses of the lumbar
vertebrae. It travels medially andcontributes to the formation of
the posterior rectus sheath.The transversalis fascia forms the
innermost layer of the posteriorrectus sheath throughout.The RAM
and its aponeurotic margin possess two mainfunctions: tensioning
the abdominal wall, maintaining itscontents, and flexioning the
first 30 when passing from thesupine to the sitting
position.Arterial anatomy of the regionThe thoracic and abdominal
aorta provide the blood supplyof the abdominal wall through two
main sources: the deepsuperior epigastric artery (DSEA) and DIEA.
There are alsosecondary sources of blood supply provided by the
posteriorintercostal arteries, subcostal artery, and lumbar
arteries. Theaortic branches follow the nerve branches along a
posterioranterior path. There exists a superficial superior
epigastricartery, another branch of the internal mammary artery.
Thisapparently provides blood supply to the superficial layer ofthe
fat in the same manner as the superficial inferior
epigastricartery.The internal mammary artery branches into the
DSEAand the musculophrenic artery deep to the sixth
intercostalspace on each side. The deep superior epigastric artery
thenruns from the plane superficial to the transversus
thoracismuscle inferiorly to pass between the diaphragmatic
originson the xiphoid process and costal margin, respectively.
Ithas three branches: the medial and lateral branches and alateral
segmental branch which becomes the eighth anteriorintercostal
artery. The DSEA gives off the superficial superiorepigastric
artery. This artery perforates the anterior rectussheath and
travels in the subcutaneous tissue parallel to theeighth anterior
intercostal artery.The deep superior epigastric vessels run
inferiorly deep tothe rectus abdominis and superficial to the
fibrous layer thatforms the posterior leaflet of the rectus sheath.
Normally,the superior epigastric artery runs medial to the middle
ofthe muscle (approximately 2.54 cm from the midline).Within this
layer it ramifies to widely anastomose with theinferior epigastric
artery. The superior epigastric artery suppliesthe peripheral
portion of the anterior diaphragm andthe superficial muscles of the
anterior abdominal wall.The inferior epigastric artery arises from
the external iliacartery, immediately above the inguinal ligament.
The originmay occur at any part of the external iliac artery
betweenthe inguinal ligament and a point 6 cm above it, or it
mayarise below this ligament, from the femoral artery. It
frequentlysprings from the external iliac artery, by a commontrunk
with the obturator artery. Sometimes it arises fromthe obturator
artery, the latter vessel being furnished by thehypogastric artery,
or it may be formed by two branches,one derived from the external
iliac artery, the other fromthe hypogastric artery. It curves
forward in the subperitonealtissue, and then ascends obliquely
along the medialmargin of the abdominal inguinal ring; continuing
itscourse upward, it pierces the transversalis fascia
(approximatelyat the level of the anterior iliac spine) and,
passingin front of the linea semicircularis, ascends between
therectus abdominis and the posterior lamella of its sheath.
Itfinally divides into numerous branches which anastomose,above the
umbilicus, with the superior epigastric artery andwith the lower
intercostal arteries. As the inferior epigastricartery passes
obliquely upward from its origin, it lies alongthe lower and medial
margins of the abdominal inguinalring, and behind the commencement
of the spermatic cord.The ductus deferens, as it leaves the
spermatic cord in themale and the round ligament of the uterus in
the female,winds around the lateral and posterior aspects of
theartery.The main branches of the DIEA are: the external
spermaticartery, which accompanies the spermatic cord; a
pubicbranch that runs along the inguinal ligament and thendescends
along the medial margin of the femoral ring tothe back of the pubis
and there anastomoses with the pubicbranch of the obturator artery;
muscular branches, some ofwhich are distributed to the abdominal
muscles and peritoneumanastomosing with the iliac circumflex and
lumbararteries; and branches which perforate the tendon of
theobliquus externus and supply the integument, anastomosingwith
branches of the superficial epigastric artery.Flap anatomyArterial
supply of the flap (see Figure 19.1)The RAM exhibits double
nourishment (type III Mathes/Nahai) and is supplied superiorly by
the superior epigastricartery, a branch of the internal thoracic
artery, and by theDIEA, a branch of the external iliac artery.
These two vesselscomprise an intramuscular anastomotic network with
eachother above the level of the umbilicus. This vascular
systemalso anastomoses with the intercostal branches. Alongits
course, these arteries emit perforating branches directedtoward the
skin to irrigate it.Dominant: deep inferior epigastric artery(see
Figure 19.1)Length: 7 cm (range 68 cm)Diameter: 3.5 mm (range 35
mm)The inferior epigastric artery arises superior to the
inguinalligament and passes superomedially in the layer superior
tothe peritoneum but deep to the transversalis fascia. Medially,it
passes deep to the conjoint tendon. At the level ofthe arcuate line
(46 cm above the pubic bone), it passessuperiorly and superficially
to perforate the posterior leafletof the rectus sheath. Clinically,
the arcuate line is importantas the site of entry of the inferior
epigastric artery intothe rectus sheath. The DIEA enters the rectus
muscle in itslateral third and divides into a medial and lateral
branch.These branches provide perforators to the skin at
variouslocations. Within the rectus sheath, the inferior
epigastricartery passes superiorly and ramifies to anastomose
withthe superior epigastric artery. It lies within the
neurovascularplane of the transversalis fascia and transversus
abdominisaponeurosis.After entering the RAM, the DIEA divides into
a medialand a lateral branch. Perforating branches responsible
fornourishment of the skin of the inferior abdominis flap
originatefrom these branches. Two types of perforating vesselsare
visible:l Perforators with a straight intramuscular path located
inthe intermuscular septum in the direction of the
subcutaneoustissue. In this case the intramuscular course of
thevessel is short and perpendicular to the muscle fibers.l
Perforators with an oblique intramuscular course. Theperforating
vessel crosses two or more septa on its wayto the subcutaneous
tissue, making dissection difficultbut increasing pedicle length.
In the lateral row, 79.2%of the vessels display a rectilinear
course, whereas inthe middle row only 18.2% of the vessels present
thispattern.Dominant: deep superior epigastric arteryLength: 3 cm
(range 24 cm)Diameter: 1.5 mm (range 12.5 mm)The superior
epigastric artery is a branch of the internal thoracicartery on
each side. It forms deep to the sixth intercostalspace on each
side. The superior epigastric artery thenruns from the plane
superficial to the transversus thoracismuscle inferiorly to pass
between the diaphragmatic originson the xiphoid process and costal
margin, respectively.The superior epigastric vessels run inferiorly
deep to rectusabdominis and superficial to the fibrous layer that
formsthe posterior leaflet of the rectus sheath. Within this
layerthey ramify to widely anastomose with the inferior
epigastricartery.The superior epigastric artery is a branch of the
internalthoracic artery. In myocutaneous or perforating flaps
withinfraumbilical skin flap, the superior epigastric artery has
asecondary function in comparison to the inferior epigastricartery.
The superficial inferior epigastric artery also co-operatesin
nourishment of the anterior skin of the abdomen.The artery emerges
beneath the chest wall along the posteriorand medial aspect of the
muscle.Minor: subcostal and intercostal arteries andvenae
comitantesLength: 2 cmDiameter: 0.51 mmBranches from the thoracic
aorta, inferior vena cava, andintercostal pedicles run immediately
below each correspondingrib. At the anterior portion of each costal
arch,the vascular pedicles, associated with the intercostal
nerves,perforate the transversalis fascia, in its lateral aspect.
Thesepedicles anastomose with the superior epigastric artery
andvein within the deep surface of the rectus muscle. Althoughthere
is a real vascular anastomosis between these vessels,they play a
smaller role in the nourishment of the rectusmuscle.Flap
componentsThe flap can be dissected as a pure muscle flap, as a
segmentalmuscle flap with preservation of part of the muscle, asa
myocutaneous flap with a transverse, oblique or verticalskin island
flap, as a myocutaneous flap with muscle preservationor as a
perforator flap, with preservation of all musclesand
innervations.The seventh, eighth, ninth, and/or tenth ribs can
beincluded in a rectus abdominis flap. They are nourished bythe
seventh, eighth, and ninth intercostal vessels, which jointhe
costomarginal artery along the inferior border of thecostal margin.
The costomarginal artery then forms an anastomosiswith the superior
epigastric artery along the deepsurface of the rectus abdominis
muscle. This flap is useful inthree-dimensional reconstructions of
bony and soft tissuedefects of the face.Advantagesl The position of
this flaps skin island in the inferiorabdomen, especially in women
who have alreadybeen pregnant, is advantageous. Dissection of the
flapcan lead to a skin resection similar to a
conventionalabdominoplasty, resulting in not only a well-placed
scarbut also an improvement in body contour.l Since the flap is
dissected in the supine position, reconstructionof defects in the
anterior trunk as well as theupper and lower extremities can be
performed without achange in position during the procedure.l The
vascular anatomy is uniform and reliable. The pedicleis long and
has large-diameter vessels, simplifyingmicrovascular anastomoses.l
If it is transferred based on its superior pedicle, thewhole length
of the pedicle included in the rectus musclewill greatly increase
its rotational arc.l The design of the skin island is very
versatile. It can betransverse, vertical, and/or oblique.l In large
three-dimensional defects, the flap can befolded on itself,
providing good coverage in complexhead and neck resections.l A
muscle flap, without a skin island, can be harvestedthrough a low
transverse abdominal incision, resultingin a well-positioned
scar.DisadvantagesSince the posterior rectus sheath caudal to the
arcuate lineis composed of transversalis fascia only, weakening of
theabdominal wall after flap harvest may be seen with variationsof
the flap that include a significant part of the anteriorrectus
sheath. If only a small part of the anterior fasciaand the
abdominal wall layers are closed appropriately,weakening of the
abdominal bulgings or hernia will be lesslikely to happen.l The
removal or denervation of the RAM can create aslight functional
deficit, especially upon flexing thetrunk. However, utilizing the
perforator form of the flapminimizes this deficit (see Chapter
35).l In obese patients, the myocutaneous form of the rectusflap is
very likely to be bulky for resurfacing objectives.l This muscle
does not function well as a functional muscletransfer since its
excursion is minimal and its innervationis segmental.Preoperative
preparationPreoperative evaluation is of fundamental importance.
Adetailed history and physical examination can reveal
importantaspects of the surgical procedure. Previous abdominalor
pelvic surgeries can damage the vascularization of theflap.
Previous irradiation of the internal thoracic vessels candiminish
its blood flow. If one suspects injury of the pedicles,additional
studies should be performed.One should be aware of prior abdominal
scars, especiallytransverse ones, which can indicate previous
injuryto the pedicle. For instance, the Kocher (subcostal)
incisionusually divides most of the rectus muscle, so that the
proximallybased RAM flap may be contraindicated, though
Dopplerultrasonography may be used to check the integrity ofthe
pedicles.Prior undermining of the skin flap of abdominoplastiesis a
relative contraindication. Although reports in the
literaturemention that patients with prior abdominoplasties
havebeen subjected to harvesting of myocutaneous RAM flapswithout
complications, we do not recommend it. If one stillwants to use an
abdominal skin flap, a thorough history anddiscussion with the
previous surgeon may aid in determiningthe level and extent of
dissection during the abdominoplasty.Also, careful delay procedures
can be helpful.In obese patients, fat necrosis is a major
probabilitywhen the superiorly based pedicled form is utilized.
Microsurgicalinferiorly based flaps or delay procedures can
beindicated in this situation.If the proposed flap requires
dissection of its perforators,prior location of the pedicles with a
duplex ultrasoundstudy is recommended. Hand-held unidirectional
Dopplercan be used, although its sensibility and specificity
arelower. Although not mandatory, knowledge of the pediclesexact
location permits a speedier and accurate dissection ofthe flap.A
detailed physical examination should be performedin every patient.
One should look for abdominal muscleweakness or herniations that
should be dealt with intraoperatively.Patients in whom the internal
mammary artery hasbeen used for cardiac revascularization should
not use asuperiorly based flap. Although there is an anastomosis
ofthe costomarginal artery with the superior epigastric
artery,distal to the internal mammary artery, that may supply
therectus muscle, there are not currently sufficient data to
showthat this vessel can nourish the whole flap.Flap designAnatomic
landmarks (Figure 19.2)The RAMs are located in the anterior abdomen
with theirmedial limits situated in the midline, except in
multiparouswomen who present with diastasis of the rectusmuscles,
separating them from the midline. The superiorlimit is the rib
cage, as the muscle arises from the fifth,sixth, and seventh costal
cartilages and the inferior limitis its insertion at the pubis (see
Figure 19.1). Palpation ofthe contracted muscle easily determines
its location in thinpatients.Flap marking and general thoughts
aboutflap design and dimensionsThe design and size of the flap vary
greatly depending onthe surgical technique utilized and the
characteristics of thedonor and recipient areas. Therefore, each
transfer will beexplained individually.Our preference is to include
periumbilical perforatorsin the design of the skin paddle whenever
possible. Theseperforators are larger and provide better supply to
the skinof the abdominal wall. However, in some cases, in orderto
preserve a majority of periumbilical perforators, a
supraumbilicalincision should be used as the superior marginof the
flap. Closure of the donor site in that situation maynot allow for
the inferior incision to be placed immediatelyabove the pubic
hairline. In those situations, the inferiorincision is placed
higher in the abdomen, in a visiblelocation. The other alternative
is to place the superior incisionlower than the umbilicus and
sacrifice some of theperiumbilical perforators, allowing for a more
aestheticallypleasing incision line.Chest wall and breast
reconstructionThe most commonly employed design of the skin
portionof the flap is the transverse lower abdominal skin flap,
similarto the skin resection of an abdominoplasty. The
superiormargin of the skin island is usually 2 cm above the
umbilicus(in order to include the periumbilical perforators) andthe
inferior margin is above the pubic hairline. When thelower
abdominal skin is harvested as a myocutaneous flapbased on blood
supply traversing the rectus muscle withinclusion of the muscle in
the flap, this is called a transverserectus abdominus myocutaneous
(TRAM) flap. Thisdesign permits dissection of a thick flap, since
it is a regionthat usually accumulates some excess fat, and it
confers apleasing aesthetic result to the donor area. Variations in
flapdesign depend on the type of flap dissection
utilized.Superiorly based unipedicled myocutaneous flapThis kind of
flap dissection provides a reliable blood supplyto the ipsilateral
skin and part of the contralateral skin.However, the remaining
contralateral skin island should beresected to achieve abdominal
symmetry.Superiorly based bipedicled myocutaneous flapIf a large
amount of tissue is required, the flap based onboth RAMs may be
employed. In this case a larger flap canbe designed, because there
will be two vascular pediclesnourishing the flap. If necessary, the
flap can be designedmore proximally, although it should be borne in
mind thatin this case the resulting scar will also be higher
up.Free myocutaneous flap based on the DIEAWhen this type of
reconstruction is employed, its vascularizationis abundant and
reliable, permitting use of the entireinferior abdominal
skin.Perforator flap based on the deep inferiorepigastric
arteryDespite its sufficient arterial supply, venous congestion
isoccasionally noted on the opposite side of the DIEA.
Therefore,the fusiform design is the most recommended
perforatorflap centered on the side of the pedicle or consideration
isgiven to including the contralateral superficial inferior
epigastricvein with the flap.Other reconstructions (Figure 19.3)In
other types of reconstructions, the flap design willdepend on the
defect to be repaired. Flaps with vertical oroblique skin islands
can be utilized or even separate distinctskin islands, based on
perforator pedicles. If the design isoblique, it is possible to
utilize the skin portion abovethe rib cage that has the advantage
of being thinner andconsequently more suitable for modeling the
flap. Thisflap is designed transversely over the anterior portionof
the lower costal margin laterally all the way to the levelof the
midaxillary line. On the other hand, if volume isnecessary, a major
or minor portion of the rectus musclecan be included in the flap,
always bearing in mind thefact that about 2030% of the muscle
volume is usuallylost due to denervation of the muscle. If the
planned flapis purely muscular, it can be dissected through a
paramedianincision placed longitudinally and centered over
therectus muscle with a lateral extension in the caudal portionthat
aids in exposure of the DIEA. Or alternatively, via alow transverse
incision, followed by undermining of anabdominal flap and
dissection of the muscle flap below it.Differences in design when
performingthe flap as pedicled or freeThe placement of the skin
island may differ slightly if apedicled flap is to have an extended
reach; otherwise, theprinciples are similar and the designs
described can be usedfor both pedicled and free flaps.Flap
dimensionsSkin island dimensions: lower abdominalskin flapLength:
13 cm (range 1020 cm)Maximum to close primarily: 20 cmWidth: 25 cm
(range 2040 cm)Superiorly based pedicled TRA M flapThe dissection
begins with a superior incision followed byundermining of the upper
abdomen. Above the level of thesuperior incision, extensive
undermining laterally to the rectusmuscles should not be performed
in order to protect thenourishment of the abdominal skin flap. The
patient is thenplaced in a sitting position and by caudal traction
of theupper abdomen; the inferior limit of the flap is marked.
Thelower skin incision is completed and the skin of the flap
isundermined from lateral to medial above the plane of theexternal
oblique and its aponeurosis. Skin and subcutaneoustissue are lifted
off the external oblique muscle up to thelateral border of the
rectus abdominis muscle on both sidesof the abdomen. Normally, we
start the elevation of the flapon the contralateral side of the
abdomen first in order todetermine the location of the perforators
which would aidin defining the exact location of the vessels on the
ipsilateralside. Once a perforator vessel is found, the
subcutaneous fataround it is immediately dissected through the
fascia. Theanterior rectus sheath through which the perforator
passedis opened, and we continue to search for other perforators.In
the DIEP flap dissection, the perforator vessel is dissectedfrom
the rectus muscle fibers through a longitudinal directionsplit.This
dissection extends up to the lateral margin of theRAM. After the
medial and lateral aspect of the anteriorrectus sheath is
completely exposed, the anterior fascia isincised on its medial and
lateral aspect to expose the underlyingrectus muscle. The lateral
aspect is easily determinedby the location of the largest
perforator previously identified.However, the medial aspect is
calculated in order topreserve the maximum extension of the fascia
to performan adequate and tension-free abdominal wall closure.
Normally,the medial incision is situated 1.53 cm from themedial
aspect of the rectus muscle. The muscle can then beapproached
starting from these perforators, thereby sparingan amount of fascia
that will simplify closure of the abdominalwall.The rectus muscle
is undermined from its posteriorsheath by blunt dissection in this
loose areolar tissue plane.At the tendons intersection, the muscle
adheres to the anterioraponeurosis, so dissection becomes more
difficult. Oncethe muscle is isolated, it is sectioned, carefully
isolating andligating the DIEA. Usually, when performing a pedicled
rectusmuscle or myocutaneous flap based on the superior
epigastricvessels and there is no plan to supercharge the
deepinferior epigastric vessels, the DIEA is located at the
lateraledge of rectus sheath and divided. When additional bloodflow
is required or needed and the surgeon plans to augmentblood inflow
or venous outflow through superchargingeither the artery or the
vein, the DIEA and DIEV can bedissected to the level of the
inguinal ligament and divided.This approach permits an increase of
36 cm in pediclelength and the DIE vessels can serve as an optional
sourceof flap vascularization if an additional anastomosis is
performedbetween the divided DIE vessels and the recipientsite.
From this point on, the flap is elevated and any remainingadhesions
are cut. A tunnel in the subcutaneous plane isutilized to transfer
the flap to the thorax.In the majority of cases, the subcostal (T8)
and the sixor seven intercostal arteries represent the minor
pediclesof the superiorly based flap. Usually the subcostal
pedicleis the largest pedicle of these segmental minor pedicles
andpresents 23 cm length and a diameter between 0.5 and1 mm. This
vessel enters the midportion of the deep surfaceof the rectus
muscle at the level of the sixth and seventhcostal cartilages and
anastomoses with the superior epigastricvessels. Normally, the
subcostal pedicle associated withthe motor nerve is divided in
order to permit an adequatearc of rotation to the anterior chest.
In the situation of priorligation of the internal mammary artery
(coronary revascularization),care must be taken to preserve the
minor pediclesand especially the subcostal artery in order to
maintainthe retrograde flow to the superior epigastric artery. In
general,our experience has demonstrated that the rectus
muscleassociated with a transverse or longitudinal superior
skinisland survives when transposed based on minor
pedicles.However, the conventional superiorly based TRAM flapusing
the minor pedicles should be avoided as the vascularflow may be
unpredictable.At the beginning of flap dissection, the umbilicus is
circumscribedas a circle. Usually, the skin is incised downto the
rectus abdominis muscle fascia in order to performcomplete
isolation of the umbilicus. After donor site closureand inferior
traction of the superior abdominal flap,the new point of the
umbilicus is calculated. For thispurpose, a vertical incision
passing through this pointand equal in length to that of the
original umbilicus isperformed. The skin is incised and small
ellipses of fullthicknessskin and fat of the superior abdominal
flap areresected on either side of the vertical line to recreate
thegap in which to inset the horizontal dimension of theumbilicus.
After hemostasis, the umbilicus is exteriorizedand the 6-oclock
position of its stalk is plicated inferiorlywith non-absorbable
sutures on the rectus fascia and theedges of the navel are sutured
to the skin with 5-0 nylonsutures.Harvest of the transverse
superior skin islandand the submammary portion of the flapUsually,
the entire central abdominal wall receives vascularcontributions
from the paired rectus muscles. Thus, multipleoptions of skin
designs are possible for a rectus musculocutaneousflap. The
transverse superior skin island or thesubmammary portion of the
flap is typically located at theepigastric and subcostal regions.
The skin territory dimensionis determined by the ability to achieve
direct donor siteclosure. Although the skin island may be extended
acrossthe abdominal wall, the flap vascularization is
unpredictablebetween the midclavicular and anterior axillary
lines,especially on the contralateral side of the abdomen. The
flapcan be based on the inferior or superior pedicle and
dissectionis similar to the conventional TRAM flap. In the
inferiorlybased flap the superior muscle is divided at the
costalmargins and the DSEA is divided at the superior limit of
theskin island at the deep medial surface of the rectus muscle.In
the superiorly based flap, the inferior rectus muscle canbe divided
at the pubis if a large amount of muscular tissueis required.
Otherwise, the rectus muscle can be dividednear the inferior limit
of the skin island as a conventionalinferior TRAM
flap.Postoperative careGeneralWhen the lower abdominal skin is
included with the flap,as with breast reconstructions, positioning
the patient in asemi-Fowler position reduces skin tension on the
donor area.Excessive efforts, chiefly those that increase abdominal
pressuresuch as lifting or carrying weight, should be avoided forat
least 1 month. Drains are kept in place for about 3 daysand
hospitalization is about 5 postoperative days.Recipient siteIn
breast reconstructions, the use of a surgical brassiere is
recommendedfor about 1 month to avoid excessive tension onthe
vascular pedicle and to provide a suitable shape to the flap.In
lower extremity reconstructions, the patient must keepthe
reconstructed limb elevated for 1 week and, after thisperiod, is
encouraged to maintain the elevation when resting.Donor siteIn
breast or facial reconstructions, the patient is encouragedto
ambulate on the first postoperative day. Abdominalbinders are
recommended for 1 month. In lower extremityreconstructions, the
patient can ambulate for short distancesafter 7
days.OutcomesExpected outcomesGeneralThe RAM flap has a very
constant and reliable anatomy. Themost frequent problems are
related to partial necrosis withsuperiorly based pedicled flaps or
abdominal wall closuredefects, especially when including large
quantities of musclewith the flap.Breast reconstructionThe flap can
be shaped with sutures and resections, thusachieving an excellent
fit to the new breast. Usually thereconstructed breast has a better
shape than the oppositeone, so that a pexy or breast reduction is
needed to providesymmetry.In breast reconstructions, pedicled flaps
can cause lossof definition of the reconstructed mammary sulcus,
due tothe passage of the muscle pedicle through the
subcutaneouspath. Microsurgical flaps achieve a better definition
of themammary sulcus.Donor siteWhen a transverse design of the skin
island is used inwomen with abdominal laxity, an improvement of the
contourof the abdomen is expected, since the excess of soft
tissueis resected.Untoward outcomesGeneralThe RAM flap is very safe
as long as one respects its vascularanatomy. Small necroses of the
flap are usually related toinsufficient venous drainage and are
located at the marginsof the flap. Total flap losses are related to
technical problemswith the vascular anastomosis rather than
problemswith the dissection of the flap.The presence of small hard
nodules in the subcutaneous tissueof the flap is related to fat
necrosis. They are more commonin breast reconstructions with
superiorly based pedicled flaps.Donor siteSmall areas of necrosis
of the abdominal flap and poorumbilical scarring rarely occur, and
are probably related toextensive undermining or aggressive
dissection. They areusually treated with minor local debridement
and dressings.Seromas in the undermined areas are rare due to the
useof suction drains. However, if they should occur, they can
betreated by needle aspiration or surgical drainage.Long-term
outcomesGeneralThe RAM flap is sometimes heavy. In the long term,
theremay be a variable degree of ptosis that may require
repositioningof the flap.When the RAM flap is used in contour
restoration, onemust bear in mind that the muscle segment of the
flap willatrophy by about 2030% due to denervation.Breast
reconstructionSurgeries for remolding or repositioning of the flap
with orwithout reduction or pexy of the opposite breast are
eventuallynecessary. The flap tends to grow proportionally to
thepatients weight gain but there is generally less tendency
toptosis than in the normal breast.Postoperative radiotherapy can
reduce the size of thereconstructed breast; therefore, it is
recommended that treatmentbe concluded before procedures to achieve
symmetryare scheduled.Approximately half the patients undergoing
breast reconstructionutilizing the myocutaneous flap achieve
somespontaneous return of sensibility. This return increasesif the
perforating form of the flap is dissected, even more ifsensory
reinnervation by microsurgical nerve anastomosis
isperformed.222Section TWO Conventional workhorse flapsCase 1This
patient was diagnosed with breast cancer and underwenta
nipple-sparing mastectomy. She was reconstructedwith a free TRAM
flap based on the inferior epigastricvessels. At long-term
follow-up she was cancer freeand had maintained reasonable contour
of the breast(Figure 19.5).Donor siteHernias or bulges are not
uncommon. A careful closure ofthe aponeurotic layers can diminish
these problems. Reinforcementwith a non-absorbable mesh must be
used wheneverthere is tension on the sutures.The RAM and its
aponeurotic margin possess two mainfunctions: tensing the abdominal
wall, maintaining itscontents, and providing the first 30o of
flexion when passingfrom the supine to the sitting position. One
can expectpatient complaints related to these two functions
resultingfrom flaps that utilize the muscle, especially in patients
whoengage in intense physical activity. The utilization of
perforatorflaps, with preservation of muscles and local
innervation,seems to reduce these complaints.