male perineogenital anatomy and clinical applications in genital reconstructions...

Male Perineogenital Anatomy and ClinicalApplications in Genital Reconstructions andMale-to-Female Sex Reassignment SurgeryFrancisco Giraldo, M.D., Ph.D., María José Mora, M.D., Ph.D., Ana Solano, M.D., Ph.D.,Carlos González, M.D., and Víctor Smith-Fernández, M.D., Ph.D.Málaga, Spain

To determine the possibility of providing alternativesurgical techniques for male genital reconstruction andfor male-to-female sex reassignment surgery, the authorsundertook an anatomic investigation of the perineogeni-tal region in male cadavers. Anatomic dissection was per-formed on 14 male adult human cadavers (fresh andformalin-preserved) studying the main afferent vessels tothe anterior perineal region and their mean internal di-ameters: deep external pudendal artery (0.60 mm), su-perficial perineal artery (0.50 mm), and funicular artery(0.37 mm). We established their exact topography, to-gether with vascular anatomic variations, main vascularanastomosis circuits (base of the penis, scrotal septum,and perineal fat and lateral spermatic-scrotal fascia), an-giosomes, anatomy of the rectovesical septum cavity, andtheir “critical” key points of dissection. The authors dis-cuss the clinical possibility of elevation of a “tree” of pre-viously described paragenital-genital flaps includingmainly those based on the terminal branches of the in-ternal pudendal vascular system, the erectile tissue pedi-cled flaps, and finally, flaps of the external pudendal sys-tem. The authors indicate the concrete vascularizationsystem for each flap. (Plast. Reconstr. Surg. 109: 1301,2002.)

Although gross anatomy is well knownthrough classic treatises, most scientific ad-vances in the field of plastic surgery have comeabout as a result of investigation in the area ofcutaneous vascularization patterns in both hu-man cadavers and clinical practice. This re-search has resulted in impressive progress anddevelopment over the past 100 years, and prob-ably no other surgical specialty has achieved

such evolution, creativeness, and perfectionismin so short a period of time as has plastic andreconstructive surgery.

Either as a consequence of the lack of avail-ability of human cadavers for scientific investi-gation or difficulties secondary to technical ap-proaches in the zones concerned, the genitalsand the perineum remain two neglected areasof anatomic study, with a relatively limitednumber of publications to date, so that furtherwork in this area is necessary.

In 1991, we initiated an anatomic investiga-tion in female cadavers of perineogenital softtissues. The findings of these studies enabledus to successfully apply new techniques andapproaches in vaginal reconstructive sur-gery.1–4 We have since undertaken a similarinvestigation in male cadavers, to determinethe possibility of providing alternative surgicaltechniques to those already described for gen-ital reconstruction and for sex reassignmentsurgery.

The main afferent vessels to the skin of thegenitals and the anterior perineal region in themale anatomy are the anterior scrotal arteries,which are direct branches from the femoralvascular system; and the posterior scrotal arter-ies, which are terminal branches of the super-ficial perineal vessels from the internal iliacvascular system. In addition, there is anothervascular structure which we consider to be rel-evant in this field, the funicular artery, a prox-

From the Plastic and Reconstructive Unit, “Carlos Haya” Regional Hospital; and the Normal and Pathologic Morphology Department of theFaculty of Medicine, Málaga University. Received for publication May 1, 2001.

This work was supported by a grant (Project Exp. 0686/98) from the Fondo de Investigación Sanitaria (FIS), Instituto de Salud Carlos III,Ministerio de Sanidad y Consumo.

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FIG. 1. (Above, left) Deep external pudendal system. (1) Deep external pudendal artery, (2) internal anterior scrotal arteries,(3) external anterior scrotal arteries, (4) superficial cutaneous arteries of the penis, (5) great saphenous vein, (6) superficialexternal pudendal artery, (7) superficial vein draining the penile shaft, (8) deep dorsal neurovascular pedicles of the penis, (9)aponeurosis of the adductor longus muscle, (10) adductor longus muscle, (11) gracilis muscle, and (12) spermatic cord. (Above,right) Deep external pudendal system with the deep external pudendal arteries crossing over the saphenous hiatus. (1) Deep

1302 PLASTIC AND RECONSTRUCTIVE SURGERY, April 1, 2002

imal branch of the inferior deep epigastricartery from the external iliac system.

In this work, we report our experience in aseries of human dissections of the perineogeni-tal region in male cadavers. We describe themain vascular trunks arriving at this region, itsexact topography and anatomic variations, andthe principal anastomotic vascular circuits andtheir relation with spermatic-scrotal fascias.The internal diameters of these arteries mea-sured by means of image analysis suggested thepossibility of elevation of a “tree” of genitalflaps based on these vascular axes and theirterminal branches for applications in genitalreconstructions and male-to-female sex reas-signment surgery.

MATERIALS AND METHODS

Anatomic dissection was performed on 14male adult human cadavers (12 formalin-preserved and two fresh), useful for teachingand investigation, from the Normal and Patho-logic Morphology Department, Faculty of Med-icine, Málaga University, Spain. External exam-ination of the cadavers revealed no scars oranomalies in the perineal, genital, and ingui-nal regions. By means of macro-micro dissec-tion, the main afferent and efferent vascularstructures to the skin of the genitals and ante-rior perineal region were identified. We ana-lyzed 16 vascular pedicles (eight right, eightleft) of the superficial perineal, deep externalpudendal, and funicular arteries, and deter-mined their relation to certain anatomic land-marks, their main vascular anastomosis cir-cuits, and the internal diameters of each artery.In addition, in six cadavers, angiosomes of themain cutaneous arteries of the anterior peri-neal region were studied, and neurovascularstructures of the dorsum of the penis, the vas-cularization system of the scrotal septum, and

the anatomy of the rectovesical septum, withidentification of the “critical” key points of dis-section of the rectovesical virtual space. Neu-rovascular structures were dissected bilaterallyusing magnifying glasses (�3.5), and high-resolution photographs of the origin, distribu-tion, and topography of the vascular structureswere taken.

Arteriectomy specimens 1 cm long were har-vested from the proximal segment of the mainarteries (superficial perineal, deep external pu-dendal, and funicular) to determine their in-ternal diameters. These arterial specimenswere processed and image-system analyzed fol-lowing the same systematic procedure usedpreviously.3 The deep external pudendal arterywas isolated and cannulated unilaterally in twocadavers, and its corresponding angiosomeswere visualized by means of the intraarterialinjection of 20 ml of methylene blue, andthe stained cutaneous territories werephotographed.

RESULTS

Afferent Vessels to the Anterior Perineal Region andtheir Distribution

In eight anatomic dissections, the unvaryingpresence of three main vascular axes was de-termined (Fig. 1) as follows:

1. Deep external pudendal artery, a directbranch of the femoral artery arriving at theanterior perineal region, crossing under thegreat saphenous hiatus in seven of eightdissections (87.5 percent), and over this ve-nous structure in one case (12.5 percent) inour series. At the spermatic cord the deepexternal pudendal artery gives off thefollowing:a. Internal anterior scrotal arteries crossing

external pudendal arteries, (2) internal anterior scrotal arteries, (3) external anterior scrotal arteries, (4) saphenous hiatus, (5)superficial cutaneous arteries of the penile shaft, and (6) right testicle. (Center, left) Superficial perineal neurovascular system.(1) Superficial perineal neurovascular pedicle, (2) external posterior scrotal arteries, (3) internal posterior scrotal arteries, (4)corpus spongiosum, (5) bulbocavernosus muscle, (6) right testicle, (7) left testicle, (8) penis, (9) scrotal-spermatic fascias. (Center,right) Superficial perineal neurovascular system. (1) Superficial perineal neurovascular pedicle, (2) external posterior scrotalarteries, (3) internal posterior scrotal arteries, (4) transperineal vessels communicating both superficial perineal pedicles, and(5) bulbocavernosus muscle. (Below, left) Lateral scrotal-spermatic vascular anastomotic circuit. (1) Deep external pudendalartery, (2) internal anterior scrotal arteries, (3) external posterior anterior arteries, (4) superficial perineal neurovascular pedicle,(5) internal posterior scrotal arteries, (6) external posterior scrotal arteries, (7) lateral scrotal-spermatic fascias, (8) obturatorartery perforator, (9) penis, (10) adductor longus muscle, (11) gracilis muscle, and (12) “choke” anastomoses between theexternal posterior and anterior scrotal arteries. (Below, right) Main afferent vessels to the anterior perineal region and theirrelations with the scrotal-spermatic fascias. (1) Deep external pudendal artery, (2) internal anterior scrotal arteries, (3) externalanterior scrotal arteries, (4) superficial cutaneous artery of the penile shaft, (5) superficial perineal vascular pedicle, (6) internalposterior scrotal arteries, (7) external posterior scrotal arteries, (8) transperineal vessel, (9) funicular artery, (10) vascular circuitaround the base of the penis, (11) bulbocavernosus muscle, and (12) scrotal-spermatic fascias.

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medially over the spermatic cord and ar-riving at the base of the penis in a hori-zontal path from the origin of the deepexternal pudendal artery to the penile-pubic angle (the terminal branches to-ward the base and dorsum of the penis,ventral scrotal septum, perineal fat lo-cated between the penis and spermaticcord, and the anteromedial spermatic-scrotal fascia).

b. External anterior scrotal arteries extend-ing along the lateral scrotum (the termi-nal branches nourish the anterolateralspermatic-scrotal fascia and the soft tis-sues of the inguinocrural regions).

2. Superficial perineal artery, a terminalbranch of the internal pudendal arterywhich superficially to the perineal superfi-cial transverse muscle and the superficialperineal aponeurosis, lateral to the bulbo-cavernous muscle and 1 to 1.5 cm distantfrom the middle perineal raphe, gives offbranches at the scrotal space between theexternal spermatic fascia and the tunica dar-tos. These terminal vessels are as follows:a. Internal posterior scrotal arteries that

course along each side of the middlescrotal raphe (the terminal branchesnourishing the dorsal scrotal septum,posteromedial spermatic-scrotal fascia,and the perineal fat).

b. External posterior scrotal arteries (thedistal branches nourishing the postero-lateral spermatic-scrotal fascia).

c. Transperineal arteries, originating fromthe internal posterior scrotal arteries ordirectly from the superficial perineal ar-tery, crossing transversally over the dorsalsurface of the bulbocavernous muscle, es-tablishing vascular interconnections be-tween both superficial perineal pedicles.

3. Funicular artery, a proximal branch of thedeep inferior epigastric artery that, crossingbelow the inguinal ligament, comes to theanterior perineum joined to the surface ofthe spermatic cord giving off terminalbranches to the cord, the base of the penis,perineal fat, and the posteromedial sper-matic-scrotal fascia.

Venous Drainage of the Anterior Perineal Region

There are venae comitantes to the threemain arterial axes as previously described, al-though superficial cutaneous venous drainageof the penile shaft may basically either go lat-

erally toward the deep external pudendal ve-nous system or ventrally toward the infraum-bilical venous plexus and both superficialinferior epigastric and external pudendal ve-nous systems just over the abdominal Scarpafascia (Fig. 1).

Vascular Anastomotic Circuits

In all eight specimens studied, three termi-nal vascular anastomotic zones were identified(Fig. 1) as follows:

1. Base of the penis. This vascular circuit isbasically formed by the bilateral confluenceof the terminal branches of the internalanterior scrotal arteries, funicular arteries,and internal posterior scrotal arteries. Inaddition, fine terminal branches of the su-perficial external pudendal artery often de-scend toward the penopubic skin fold.

2. Scrotal septum and perineal fat. This circuitis composed of afferent vessels, basicallyfrom the internal posterior scrotal arteries,and also by additional blood supply fromdistal branches of the internal anterior scro-tal, transperineal, and funicular arteries.

3. Lateral spermatic-scrotal fascia. Adhered in-timally to the external and internal spermat-ic-scrotal fascias, the internal and externalpudendal arterial systems branch off form-ing, respectively, a dorsal and ventral ar-borization pattern or a vascular mesh fromthe proximal to the distal scrotal sac. Thisanastomotic circuit is well defined and par-ticularly important at the lateral portion ofthe scrotal sac, and it is basically formed bythe anterior and lateral branches of thedeep external pudendal artery and the lat-eral and posterior branches of the superfi-cial perineal artery. This represents an anas-tomotic circuit between the lateral terminalbranches of both pudendal systems, the in-ternal and the external. Secondary muscu-locutaneous perforants from the medial ad-ductor muscle (lateral femoral circumflexartery) and gracilis muscle (obturator ar-tery) complete this vascular circuit. Bothanterior and posterior scrotal arteries arelocated between the spermatic-scrotal fas-cias and the dartos muscle of the scrotum(the so-called scrotal space).

Arterial Diameters

Accurate measurement of the internal arte-rial diameters was accomplished by means of


image-system analysis, obtaining the followingaverage calibers: deep external pudendal ar-tery, 0.60 mm; superficial perineal artery, 0.50mm; and funicular artery, 0.37 mm. In all eightspecimens, the results on both right and leftsides were homogeneous.

Vascular Injection Studies

Cannulation of the deep external pudendalartery at its origin from the femoral artery wascarried out in two fresh cadavers, and 20 ml ofmethylene blue was injected to visualize thestained cutaneous pattern and the potentialextension of its angiosome (Fig. 2).

Penile Shaft Cutaneous Blood Supply

The previously described vascular circuitaround the base of the penis was identified anddissected in eight cadavers (Figs. 1 and 2). Thiscircuit is basically responsible for the nourish-ing system of the penile cutaneous coverage,with additional fine dorsal afferent vessels fromthe terminal branches of the superficial exter-nal pudendal artery. The vessels coming fromproximally (base) to distally (foreskin), are lo-cated in the areolar connective tissue (superfi-cial penile fascia) under the dartos and thepenile skin; the venous system is located super-ficially with respect to the superficial cutaneousarteries of the penis (terminal branches of theinternal anterior scrotal arteries), basicallypaired on the dorsal skin with further finebranches coming to the lateral and ventral cu-taneous coverage of the penis.

Lateral Scrotal-Perineal Paired Flaps

The wall of the scrotum is composed of thefollowing layers, starting at the surface: skin,dartos, external spermatic fascia, cremaster, in-ternal spermatic fascia, and vaginal (Fig. 2).The vascular and topographic study of the softtissues of the anterior perineal region in themale cadavers suggested the possibility of ele-vation of lateral scrotal-perineal paired flaps,posteriorly pedicled and connected to the su-perficial perineal neurovascular pedicle (exter-nal posterior scrotal arteries). The posteriorhalf of these flaps (under the ischiopubic bonyrami) has a fasciocutaneous vascularizationpattern with the following histologic strata: thesuperficial and medial (Colles’ fascia) perinealaponeuroses including the neurovascular pedi-cle, the posterolateral spermatic-scrotal fascias,the gracilis muscle aponeurosis, the smoothmuscular fibers of the dartos, and the supraad-

jacent scrotal-perineal skin. Complete eleva-tion of this flap requires transection of theproximal perforator of the gracilis muscle, lo-cated near the ischiopubic bone, and comingfrom the obturator artery.

The anterior half of the lateral scrotal-perineal flaps (over the ischiopubic bony rami)has a direct vascularization pattern formed byanastomosis with the external anterior scrotalarteries, terminal branches of the deep exter-nal pudendal artery. To avoid injuries to thesevessels, it is necessary to elevate the adductormuscle aponeurosis at the deep plane of thelateral scrotal-perineal flap, cauterizing thefine myocutaneous perforators piercing the ad-ductor muscle and coming from the lateralfemoral circumflex artery.

The lateral scrotal-perineal flaps may be ven-trally extended to the deep external pudendalangiosome, although we advise not going be-yond the greater saphenous vein distally. Cuta-neous nerves coming from the internal puden-dal nerve accompany the lateral scrotal-perineal vessels, so the posterior one-third ofthe flaps is sensate.

Penile Glans Neurovascularization

In all our dissections, we found the typicallydescribed double neuroarterial system with acommon venous drainage (Fig. 2). Emergingfrom the distal Alcock’s canal approximately1.5 cm from the pubic symphysis on both sidesare paired neuroarterial pedicles—terminalstructures from the internal pudendal pedi-cle—running along the penis beneath Buck’sfascia and over the albuginea of the corporacavernosa. The deep dorsal venous system iscomposed of a unique vein in the middle ofthe penile dorsum between both corporacavernosa bodies, although this vessel maydivide proximally at the decussation of thecrura and also give off one or two perforantswith the superficial suprapubic venous plexus.In most specimens, the neurovascular struc-tures on the dorsum of the penis are locatedaccording to the palindrome “NAVAN”(nerve-artery-vein-artery-nerve).

Finally, the deep dorsal arteries of the penisgive off short perforants that pierce the albug-inea and bilateral lateral branches, which forma deep vascular circuit around the penis. Thedorsal nerves run over these circumflex vesselsfrom proximal to distal.


FIG. 2. (Above, left) Intraarterial injection (methylene blue) of the deep external pudendal artery showing the angiosome thatcan potentially be captured by flaps based on the terminal branches of the internal pudendal vessels. (Above, right) The skin oflateral scrotal-perineal fasciocutaneous flaps has been removed, showing the lateral scrotal-spermatic fascias, the lateral anas-tomotic circuit, and the anterior extension of these flaps. (Center, left) In a fresh cadaver, the deep dorsal neurovascular pediclesof the penis have been dissected, opening Buck’s fascia to show the anatomic disposition following the palindrome “NAVAN”(nerve-artery-vein-artery-nerve). (Center, right) A neurovascular island flap of the glans penis has been elevated, skeletonizing the


Rectovesical Space

Midline sagittal sections of the whole pelvisin two male cadavers were carried out to studythe length of this virtual cavity, and the “criti-cal” key points of dissection of the rectovesicalspace (Fig. 2). The mean distance from theperineal skin to the peritoneal inferior reflec-tion (Douglas pouch) was 11.5 cm, addition offurther length by means of blunt digital dissec-tion being difficult. The key point for adequateopening of this space, without risking perfora-tion of the urethra and/or the rectum, is care-ful sharp dissection of the rectourethral mus-cle. This structure is formed of densefibromuscular tissue closely adhering the mem-branous urethra to the anterior convexity ofthe rectum ampule, and it is found behind thecorpus spongiosum 4 to 5 cm deep with respectto the perineal skin. Surgical division of thisfibromuscular structure requires sharp dissec-tion with fine scissors once the two lateral rec-tal spaces have been dissected easily by meansof blunt digital dissection.

DISCUSSION

The anatomy of the perineum and the gen-itals has been well described in classic treatises,although recent studies of its cutaneous vascu-larization system have been decisive for en-hancement of genital reconstructive surgery.However, there has been very little scientificinvestigation concerning the exact topo-graphic anatomy of the main afferent and ef-ferent vessels of the perineogenital skin, to-gether with their corresponding clinicalapplications in the field of surgery.

Although many useful genital and parageni-tal flaps have been described over the years byauthors who have focused their efforts on thisinteresting and challenging area, from time totime reconstructions are reported using newgenital flaps based on different terminal vesselsof the main vascular systems afferent to thegenitoperineal region. During the past two de-cades, the internal pudendal artery and its ter-minal branches have possibly been the most

frequent objects of investigation, and many dif-ferent perineal axial flaps have been used forreconstruction of congenital malformations,for acquired genital defects, and for sex reas-signment surgery.

In female patients, and as far as we areaware, Morton et al.5 in 1986 were the first touse labioscrotal fasciocutaneous flaps based onthe superficial perineal artery for treatment ofsevere vaginal stenosis in two patients with ad-renogenital syndrome. Hagerty et al.6,7 usedsimilar triangular flaps for acquired vaginal de-fects. Wee and Joseph8 in 1989 described the“Singapore flap” or neurovascular pudendal-thigh flap for complete vaginal reconstruction,and Woods et al.9 in 1992 used the “modifiedSingapore flap” for complex postoncologic re-constructions. Giraldo et al.1,2 described the“Málaga flap” or vulvoperineal fasciocutaneousflap for reconstruction of neovaginas in theMayer-Rokitansky-Kuster-Hauser syndrome.Further experience has been accumulated byothers who have achieved satisfactory out-comes with flaps based on the superficial per-ineal artery.

In male patients, the terminal vessels of theinternal pudendal vascular system have alsobeen used for genital reconstructions, basicallyfor coverage of acquired perineogenital de-fects and sex reassignment surgery in male-to-female transsexuals. Since the initial descrip-tion of Jones et al.10 in 1968, many others haveused the posterior scrotal flap for vaginoplastyin male-to-female transsexuals. Huang11 in1995 used two neurovascular inguinopudendalflaps combined with a penile skin flap for vag-inoplasty in sex reassignment surgery. Karim etal.12 and Hage13 reported a very large and suc-cessful series of vaginoplasties in male transsex-uals, adding to the anteriorly based penile cu-taneous flap a triangular perineoscrotal middleflap (3 � 10 cm) to complete the posteriorneovaginal wall. Knol and Hage14 in 1997 pub-lished the infragluteal skin flap, based on theanterior perineum, for reconstruction of rec-

neurovascular structures. (1) Transversal section of the penis at the bifurcation of the corpora cavernosa, (2) corpora cavernosa,and (3) corpus spongiosum. (Below, left) Sagittal section of a pelvis in a male cadaver. (1) Penis with corpora cavernosa andalbuginea, (2) corpus spongiosum or bulb of penis, (3) scrotal septum, (4) anal canal, (5) rectum, (6) prostate, (7) urinarybladder, (8) pubic symphysis, (9) retropubic space with venous plexus, and (10) sigmoid colon. (Below, right) Close-up view ofthe key points of dissection of the rectovesical space. (1) Corpus spongiosum, (2) rectum, (3) urogenital diaphragm withmembranous urethra, (4) rectourethral muscle, (5) anterior wall of the rectum, (6) Denonvilliers aponeurosis, (7) rectovesicalspace, (8) Douglas pouch, (9) prostatic urethra, (10) urinary bladder, (11) interpubic disc, and (12) retropubic space showingsection of the deep dorsal vein of the penis and the prostatic vascular plexus.


tovaginal fistulas in female patients and male-to-female transsexuals.

As a result of our anatomic study of thecutaneous angiosomes of the anterior perinealregion in human male cadavers, we considerthe following clinical applications to be ofinterest:

Flaps Based on the Internal Pudendal System

1. Cutaneous and fasciocutaneous flaps.a. Scrotal flaps based on both superficial per-

ineal arteries. Internal and external poste-rior scrotal arteries are final divisions of thesuperficial perineal artery and these termi-nal vessels nourish the internal pudendalcutaneous angiosome, which is integratedbasically by the posterior half of the scro-tum and the adjacent crural skin. A cen-trally pedicled or island scrotal sensate flapas large as 5 cm wide by 10 to 12 cm longincludes the superficial perineal artery to-gether with its internal and external poste-rior scrotal arteries and complementaryvascularization from the superficial peri-neal transverse artery, which runs along thecentral perineum between the anus andthe perineum-scrotum; this is the vascularanatomic basis of the biaxial scrotal flaps ofJones,10 Small,15 Eldh,16 and Van Noort andNicolai.17 Finally, the cutaneous shaft of thepenis can be included in continuity withthe posteriorly pedicled scrotal flap, as de-scribed by Edgerton and Bull18 for vagino-plasty in sex reassignment surgery, the vas-cular circuit at the base of the penis beingresponsible for its reliable distal perfusion.

b. Scrotal-perineal flaps based on the internalposterior scrotal arteries. The neurovascu-lar inguinopudendal flap as described byHuang11 is typically designed in an oblongfashion, including the inferolateral tissuesof the scrotal sac and, at its base, the inter-nal posterior scrotal and the superficialperineal transverse arteries; this is an axialflap, at least in its posterior third, but notso distally. The central perineoscrotal flapof Karim et al.12 and Hage13 includes thescrotal septum, and even though it is verylong and has a limited width (3 � 10 cm),this is a secure and robust flap because ofits biaxiality specifically nourished by bothinternal posterior scrotal arteries. Thesame vascular basis is present in the biaxialepilated scrotal flap, as described by Gil-Vernet et al.19 in 1997 for treatment of

proximal bulbar and bulbomembranoustranssphincteric strictures or panurethralstrictures. The two latter flaps are alsosensate.

c. Scrotal-perineal flaps based on the externalposterior scrotal artery. Anatomically andclinically, we have gathered evidence of thepossibility of elevation of scrotal-perinealflaps20,21 including the scrotal skin, dartos,and both spermatic and perineal fasciasproximally, and the scrotal-inguinal skinand the aponeuroses of the gracilis andmedial adductor muscles distally. The mainvascular system is the external posteriorscrotal and the perineal superficial trans-verse arteries. Thus, this is an axial flap, atleast in its posterior two-thirds, whereas thecirculation at its distal third is guaranteedby the “choke” anastomoses between theinternal and external pudendal angio-somes. These flaps retain sensation at theirproximal segments.

d. Paraperineal flaps based on the perinealsuperficial transverse and inferior rectal ar-teries. Flaps mainly nourished by these lat-eral vessels branching off the internal pu-dendal artery have in common the fact thatthey include at their base the soft tissues ofthe central perineum. Examples includethe “lowermost” lotus petal flap describedby Yii and Niranjan22 in 1996, and the sim-ilar infragluteal skin flap described by Knoland Hage14 in 1997. Only the base of thisflap is sensate.

2. Erectile tissue pedicled or island flaps.a. Dorsally pedicled sensory island flap of the

glans penis. This is a sensate and erectileflap nourished and innervated by the ter-minal branches of the internal pudendalartery, the dorsal neurovascular pedicles ofthe penis. This is a well-known flap de-scribed initially by Hinderer23,24 in 1974 forneoclitoral reconstructions in the adreno-genital syndrome, and later used byBrown25,26 for neoclitoroplasty in male-to-female transsexuals. It is recognized todayas the best choice for neoclitoroplasty andthe “gold standard” against which otherprocedures are compared.

b. Pedicled urethrobulbar flaps. These flapsinclude the whole urethra, with or withoutthe glans, and are vascularized by the bul-bar arteries, which are the first branches ofthe common penile artery at the penilehilum and penetrate the corpus spongio-


sum at the 2-o’clock and 10-o’clock posi-tions, according to the fine anatomic studyof Martínez-Piñeiro et al.27 A tubular ure-thra and corpus spongiosum design withthe glans anchored at its distal apex28 hasbeen used for neoclitoroplasty and a dor-sally spatulated ureterobulbar flap with theventral glans anchored at its distal part29

for neovaginoplasty with a “pseudocervix”in male-to-female transsexuals.

Flaps of the External Pudendal System

Dorsally pedicled penile skin flap. This is anaxial flap basically nourished by the internalanterior scrotal arteries, terminal branches ofthe deep external pudendal artery.30 Additionalvascularization comes from the terminal vesselsof the posterior scrotal arteries and fine termi-nal branches of the funicular artery. Therefore,this tubular cutaneous flap, either ventrally ordorsally pedicled, has a robust and secure vas-cularization formed by distal anastomoses (atthe base of the penis) of three different vascularsystems: deep and superficial external puden-dal, internal pudendal, and deep inferior epi-gastric arteries.

When an abdominally pedicled penile shaftflap is used in transsexual surgery, to achievemaximum neovaginal depth we need a poste-rior advancement of this flap from the supra-pubic skin to the cavernosa stumps, anchoredwith two stitches, placed 2 cm ventrally of thepenopubic angle, to prevent vascularizationproblems derived from trapping of the afferentvessels of the penile shaft flap. For many goodreasons, this is the most frequently used flapand the gold standard for neovaginal recon-struction in male-to-female transsexuals. Ouranatomic study of the anterior perineal regionin male cadavers provides an approximation tothe accurate knowledge of the vascular basis ofthe perineogenital skin that may allow easierunderstanding and reliable design and man-agement of flaps in genital reconstructions andin sex reassignment surgery.

Francisco Giraldo, M.D., Ph.D.Plastic and Reconstructive UnitCarlos Haya Regional Hospital29010 Málaga, [email protected]

ACKNOWLEDGMENTS

We would like to express our gratitude to Dr. José M.Smith-Agreda, chief of the I Morphologic Sciences Depart-ment at the Faculty of Medicine, and our fondest apprecia-tion to Manuel Villena, María D. Villatoro, and María Victoria

Anaya for their support in dissections and help in histologicpreparations. We thank Ian Johnstone for his help with theEnglish language version of the manuscript.

REFERENCES

1. Giraldo, F., Gaspar, D., González, C., et al. Treatmentof vaginal agenesis with vulvoperineal fasciocutaneousflaps. Plast. Reconstr. Surg. 93: 131, 1994.

2. Giraldo, F., Solano, A., Mora, M. J., et al. The Malagaflap for vaginoplasty in the Mayer-Rokitansky-Kuster-Hauser syndrome: Experience and early-term results.Plast. Reconstr. Surg. 98: 305, 1996.

3. Giraldo, F., Mora, M. J., Solano, A., et al. Anatomicstudy of the superficial perineal neurovascular pedi-cle: Implications in vulvoperineal flap design. Plast.Reconstr. Surg. 99: 100, 1997.

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male perineogenital anatomy and clinical applications in genital reconstructions...

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