Perforator-to-Perforator MusculocutaneousAnterolateral Thigh Flap for Reconstructionof a Lumbosacral Defect Using the LumbarArtery Perforator as Recipient VesselMarc A.M. Mureau, M.D., Ph.D.1 and Stefan O.P. Hofer, M.D., Ph.D., F.R.C.S.(C)1,2

ABSTRACT

Reconstruction of large-sized lumbosacral or sacral defects often is not possibleusing local or regional flaps, making the use of free flaps necessary. However, the difficultyof any microsurgical procedure in this region is complicated by the need to search forpotential recipient vessels to revascularize the flap. In the present case, a free musculocuta-neous anterolateral thigh flap to cover a large-sized and deep lumbosacral defect was used.Arterial anastomosis was performed, connecting the cutaneous anterolateral thigh (ALT)perforator to the perforator of the second lumbar artery. In this fashion, the arterialcirculation through the flap was flowing reversely through the muscle. The concomitantvein of the descending branch of the lateral circumflex femoral artery was hooked up to thethoracodorsal vein using a long interposition vein graft because the perforator of the secondlumbar vein was too small. Postoperative healing was uneventful. In conclusion, asuccessful reconstruction of a lumbar defect has shown that local perforators in the lumbararea may be accessible for easier perforator-to-perforator anastomoses and that themuscular part of the musculocutaneous ALT flap can survive on retrograde arterialperfusion from a perforator of the skin island.

KEYWORDS: Lumbosacral defect, perforator, free flap, recipient vessel

Reconstruction of large-sized lumbosacral orsacral defects can often be difficult because of theanatomic features of the local tissue: it is relatively thick,adheres strongly to the underlying layers, and is relativelyinelastic.1 Therefore, attempts to cover such large defectsusing local or regional flaps often will result in necrosis offlap edges, caused by excessive tension with consequentrisk of infection and unstable wounds.1 Consequently,free flaps will often be necessary to reconstruct large-sized defects in the lumbosacral or sacral area. However,

the difficulty of any microsurgical procedure in thisregion is complicated by the need to search for potentialrecipient vessels to revascularize the flap. Some havetried to overcome this problem by connecting free flapsto the thoracodorsal1,2 or femoral vessels1,3,4 usinginterposition vein grafts or loops; others have usedthe superior gluteal,4,5 inferior gluteal,6 or intercostalvessels.7

In the present case, a free musculocutaneousanterolateral thigh (ALT) flap was used to cover

1Department of Plastic and Reconstructive Surgery, Erasmus MedicalCenter Rotterdam, Rotterdam, The Netherlands; 2Division of PlasticSurgery, University of Toronto, University Health Network, Toronto,Ontario, Canada.

Address for correspondence and reprint requests: Marc A.M.Mureau, M.D., Ph.D., Department of Plastic and ReconstructiveSurgery, Erasmus Medical Center Rotterdam, P.O. Box 2040, 3000

CA Rotterdam, The Netherlands.J Reconstr Microsurg 2008;24:295–300. Copyright # 2008 by

Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY10001, USA. Tel: +1(212) 584-4662.

Accepted: September 10, 2007. Published online: June 11, 2008.DOI 10.1055/s-2008-1080532. ISSN 0743-684X.

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a large-sized and deep lumbosacral defect (25� 10�8 cm). Arterial anastomosis was performed connectingthe cutaneous ALT perforator to the perforator of thesecond lumbar artery. The concomitant vein of thedescending branch of the lateral circumflex femoralartery was hooked up to the thoracodorsal vein using along interposition vein graft because the perforatorof the second lumbar vein was too small. To our knowl-edge, this procedure has not been previously described inliterature.

CASE REPORTA 43-year-old male patient presented with a large-sizedand deep lumbosacral defect after irradical resection of apulmonary metastasized small blue round cell sarcoma,not otherwise specified. A few months preoperatively, hehad received six cycles of induction chemotherapy(adriamycin/ifosfamide and doxorubicin/ifosfamide/eto-poside) with a good response, after which en block tumorresection and a dorsal L2 to S1 spondylodesis usingcancellous bone grafts were performed. Postoperatively,he had received local radiotherapy (total cumulativedose: 39 Gy), complicated by a deep infection of thedorsal spondylodesis for which abscess drainage had tobe performed, resulting in a deep lumbosacral defectwith exposed hardware (Fig. 1). In addition, his medicalhistory included multiple sclerosis (since 1983) withparaplegia (since 1998) and a pulmonary embolism.

After two additional debridements and high-doseintravenous antibiotic treatment, the patient was sched-uled for radical excision of the radiodermatitis areaand reconstruction with a local pedicled lumbar arteryperforator (LAP) flap. Preoperatively, the left perforatorof the second lumbar artery was localized using ahandheld Doppler (Multidopplex II, Huntleigh Health-care, Cardiff, UK). After radical debridement, the defect

measured 25� 10� 8 cm, and the subcutaneous fatthickness of the LAP flap measured only a few centi-meters (Fig. 2). Therefore, it was decided to harvest afree musculocutaneous ALT flap from the left upper legincluding the total vastus lateralis muscle to obliteratethe entire lumbosacral cavity. In search for more adjacentrecipient vessels, the cutaneous perforators of the secondlumbar artery and concomitant veins were dissectedthrough an exploring incision, and the arterial flow waschecked and found to be adequate (Fig. 3). Because theperforator of the second lumbar artery was rather small(1 mm) and did not match the descending branch ofthe lateral circumflex femoral artery (3.5 mm), it wasanastomosed end-to-end to the most cranial of threecutaneous perforators of the ALT flap (after it wasdissected and transected). In this fashion, the arterialcirculation through the flap was flowing reversely

Figure 1 Chronic lumbosacral defect after previous de-

bulking of a small blue round cell sarcoma followed by a

dorsal L2 to S1 spondylodesis and postoperative radiother-

apy (39 Gy) complicated by a deep abscess formation, which

had to be drained.

Figure 2 Lumbosacral defect after radical debridement

measuring 25� 10� 8 cm. The proximal base of a left-sided

lumbal artery perforator (LAP) flap is flipped, laterally expos-

ing the perforating vessels of the second lumbar artery and

veins. Please note that the LAP flap is only a few centimeters

thick, making it unsuitable to obliterate the defect.

Figure 3 Magnification of the perforating vessels of the

second lumbar artery and veins. The deep fascia and latissi-

mus dorsi muscle fibers are split, exposing the left erector

spinae muscle through which the lumbar perforating vessels

run.

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through the muscle (Fig. 4). Next, an attempt was madeto anastomose one of the concomitant perforating veinsof the second lumbar vein to the vein accompanyingthe arterial cutaneous ALT perforator. However, after15 minutes, the flap became severely congested despite arevision of the venous anastomosis. The venous con-gestion resolved after opening the concomitant vein ofthe descending branch of the lateral circumflex femoralartery. Therefore, the latter vein was connected to thethoracodorsal vein using a 35-cm-long greater saphe-nous vein interposition graft, which was subcutaneouslytunneled to the left axilla (Figs. 4 and 5).

Postoperatively, the patient was nursed in a rightdecubital position for 4 weeks and high-dose intravenousantibiotic treatment was continued. After 4 weeks, thepatient was allowed to sit in his wheelchair with adjustedbackrest, and after 6 weeks, he was allowed to lift himselfusing both arms forcefully to make transfers. All wounds

healed uneventfully (Figs. 6 and 7), and the patient waskept on oral antibiotics for a period of 6 weeks.

DISCUSSIONLarge-sized lumbosacral or sacral defects are encoun-tered relatively infrequently. These large defects some-times can be closed using large bilateral myocutaneous or

Figure 4 Schematic drawing of microsurgical anasto-

moses and blood flow directions of perforator-to-perforator

myocutaneous anterolateral thigh flap. LAP, lumbal artery

perforator; ALT-P, anterolateral thigh flap perforator; VL,

vastus lateralis muscle; DB-LCFA, descending branch of

lateral circumflex femoral artery; VG, vein graft; TDV, thor-

acodorsal vein.

Figure 5 Direct postoperative result after reconstruction

of the lumbosacral defect with a myocutaneous anterolateral

thigh free flap. The perforator of the second lumbar artery

was anastomosed to the most cranial cutaneous perforator

of the anterolateral thigh flap. The concomitant vein of the

descending branch of the lateral circumflex femoral artery

was connected to the thoracodorsal vein using a 35-cm-long

greater saphenous vein interposition graft, which was sub-

cutaneously tunneled to the left axilla.

Figure 6 Result 3 weeks postoperatively, showing a small

fistula at the caudal side of the flap, which closed sponta-

neously.

Figure 7 End result 4 months postoperatively, showing a

completely healed wound without signs of a chronic or deep

infection.

PERFORATOR-TO-PERFORATOR MUSCULOCUTANEOUS ALT FLAP/MUREAU, HOFER 297

fasciocutaneous transposition flaps if the gluteal vesselsare intact and the area has not been irradiated previously.A disadvantage of traditional myocutaneous flaps, aswith the gluteus maximus V-Y advancement flaps, isthe need to damage the gluteus maximus muscles withpossible muscle strength reduction and gait disturbancesin ambulatory patients.8,9 A disadvantage of traditionalfasciocutaneous gluteal rotation flaps is the need toundermine these flaps extensively, ligating many perfo-rators, which makes the vascularization of these flaps lessreliable with a high risk for flap edge necrosis.1,9 Thisrisk for wound-healing complications after using localor regional flaps is even higher after previous localradiotherapy.4

Since the introduction of perforator flaps, ouranatomic knowledge on the vascularization of skinterritories has risen dramatically and many new pedicledas well as free perforator flaps have been described. Forlumbosacral defects, several unilateral and bilateral flapsbased on perforators of the lumbosacral region have beenpublished.9–12 Anatomic studies and clinical serieshave proven the reliability of such local pedicled islandperforator flaps, which can be as large as 12� 27 cm witha skin territory extending from the posterior midline tothe lateral border of the rectus sheath.9–12

Initially, we planned a pedicled LAP flap for ourpatient, as the defect was located too cranial to be closedwith conventional (myo)cutaneous gluteal transpositionflaps or gluteal artery perforator flaps. After radicaldebridement, however, the size of the wound measured25� 10� 8 cm and was deemed to be too large to beobliterated with this local flap, which was only a fewcentimeters thick. Therefore, a free myocutaneous ALTflap was chosen including the vastus lateralis muscle tofill the defect because of its bulk, reliability, long vascularpedicle, and minor donor site morbidity.2,13 Because thesecond lumbar perforators had already been dissectedand appeared to be suitable for microvascular anastomo-sis, an attempt was made to preclude the need for veingrafts to distant recipient vessels. However, there wasa major diameter incongruence between the arteriallumbar perforator (1 mm) and the descending branchof the lateral circumflex femoral artery (3.5 mm). There-fore, it was anastomosed to the most cranial cutaneousperforator of the ALT flap, making it a perforator-to-perforator free flap14 with retrograde arterial flowthrough the muscular part of the flap. Unfortunately,the concomitant perforating veins were too small todrain the venous outflow of the large myocutaneousALT flap, which became severely congested despite arevision of the venous anastomosis. Maybe these veinswere too small for regular microsurgical techniques,making supermicrosurgical techniques and instrumentsnecessary.14 Therefore, the concomitant vein of thedescending branch of the lateral circumflex femoralartery was connected to the thoracodorsal vein using

a 35-cm-long greater saphenous vein interpositiongraft.

This case report makes two interesting points:first, it raises the possibility to connect a flap in the barrenlumbar vascular territory to a recipient perforator. Aperforator is far easier to find and anastomose to thanits source vessels, which have a deep course underneaththe bulky muscles in this area.5,6,15 Unfortunately, in thiscase it was only possible for the artery because theconcomitant veins were too small to sufficiently drainthe flap and/or for standard microsurgical techniques andinstruments. Second, the muscular part of this muscu-locutaneous ALT flap was perfused retrogradely througha skin island perforator. This gives further evidence of thevascular plasticity of free flaps as has been reported pre-viously for other uncommon modes of retrograde, arte-rialized, or venous blood supplies to different flaps.16–18

In conclusion, a successful reconstruction of alumbar defect has shown that local perforators in thelumbar area may be accessible for easier perforator-to-perforator anastomoses and that the muscular part of themusculocutaneous ALT flap can survive on retrogradearterial perfusion from a perforator of the skin island.

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