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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.
1301
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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
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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
1304 PLASTIC AND RECONSTRUCTIVE SURGERY, April 1, 2002
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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.
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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
1306 PLASTIC AND RECONSTRUCTIVE SURGERY, April 1, 2002
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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.
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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-
1308 PLASTIC AND RECONSTRUCTIVE SURGERY, April 1, 2002
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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
part29for 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]
ACKNOWLEDGMENTSWe 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.
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