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.