Download SURGICAL ANATOMY OF RADICAL PROSTATECTOMY

Special Article
Arch. Esp. Urol. 2010; 63 (4): 255-266
SURGICAL ANATOMY OF RADICAL PROSTATECTOMY: PERIPROSTATIC FASCIAL
ANATOMY AND OVERVIEW OF THE URINARY SPHINCTERS
Fernando P. Secin and Fernando J. Bianco.
Urology Section. CEMIC. Buenos Aires. Argentina.
Columbia University Division of Urology. Mt. Sinai Medical Center. Miami Beach. USA.
Summary.- Advances in the understanding of prostate and pelvic anatomy in recent years made a substantial contribution to improve the surgical technique for
the treatment of prostate cancer (PC) with the potential
preservation of anatomic structures responsible for erectile and urinary function postoperatively. Knowledge of
these anatomic structures is key to achieve a complete
removal of the prostate and seminal vesicles while preserving the best possible quality of life. The literature on
prostate and pelvic anatomy has been reviewed and an
updated notion of the surgical anatomy is herein provided.
Keywords: Prostate cancer · Anatomy · Radical
prostatectomy
Resumen.- Los avances en la comprensión de la anatomía de la próstata y de la pelvis en los años recientes
han significado una contribución sustancial para mejorar la técnica quirúrgica en el tratamiento del cáncer
de próstata (CaP), con la preservación potencial de las
estructuras anatómicas responsables de las funciones
eréctil y urinaria postoperatoria. El conocimiento de estas estructuras anatómicas es la llave para conseguir
una extirpación completa de la próstata y las vesículas
seminales preservando a la vez la mejor calidad de
vida posible. Revisamos la literatura sobre la anatomía
de la próstata y la pelvis y hacemos una puesta al día
de la anatomía quirúrgica.
Palabras clave: Cáncer de próstata. Anatomía.
Prostatectomía radical.
INTRODUCTION
@
CORRESPONDENCE
Fernando P. Secin
Hospital Universitario CEMIC
Av. Galvan 4120 C1431 FWO
Ciudad Autónoma de Buenos Aires (Argentina)
[email protected]
Accepted for publication: May 30th, 2009
“In general surgeons who know the anatomy
protect the patient by virtue of less blood loss,
better margins of resection and greater functional
preservation” (Robert P. Myers) (1).
Radical prostatectomy (RP) is the only primary
treatment modality of localized prostate cancer (PC)
that has proved its effectiveness against watchful
waiting in a clinical randomized trial (2). Advances
in the understanding of prostate and pelvic anatomy
in recent years have contributed to improvements in
surgical technique that translated into outstanding long
term survival results with reasonably good, though
far from optimal, functional outcomes in experienced
hands, no matter what surgical technique was chosen,
that is, open, (3-7) laparoscopic (8-10) or robotic (1114) RP.
256
F. P. Secin y F. J. Bianco.
One aspect that is crucial to the understanding
of the complex anatomy of the male pelvis is its
significant individual variation. Some pelves are
wide, making the prostate easily accessible, whereas
other pelves are deep and narrow, complicating the
access to the prostate particularly at the moment of
performing a nerve-sparing surgery or a watertight
urethrovesical reconstruction (15).
Reference lists of retrieved articles were
scrutinized for additional relevant articles. One
hundred and three citations were selected for this
review based on their relevance, study size, study
design and overall contribution to the field.
The neurovascular structures surrounding the
prostate may also vary from patient to patient, and
the surgeon should be ready to understand those
variations in order to tailor the surgical technique to
the intraoperative findings (16-18).
Type and extent of cavernous nerves and neurovascular
“bundle” dissection (NVB)
The objective of this manuscript is to provide
an updated summary of the litera-ture on peri-prostatic
anatomy and the structures that are considered
crucial to achieving the five main objectives of
an ideal radical prostatectomy: complete cancer
removal with negative surgical margins, preservation
of urinary continence, early recovery of erectile
function, minimal blood loss and no perioperative
complications. However, on some occasions,
achieving one goal will affect achievement of one
or more of the others and vice versa. For instance,
patients with locally advanced tumors will require
resection of additional periprostatic tissue that will
hamper recovery of erectile function, and sometimes
urinary continence. In contrast, excessive obsession
with preserving the cavernous nerves may jeopardize
complete cancer resection, with the possibility of
leaving cancerous tissue behind. Additionally, the
surgeon may have to concede additional blood
loss in order to make an adequate preservation of
cavernous nerves.
Herein we will primarily focus on the
understanding of the periprostatic fascial anatomy
and the different extents of neurovascular bundle
dissection in relation to the location and distribution of
the cavernous nerves. Then, we provide an overview
of the configuration of the urinary sphincter and its
supporting structures.
METHODS
A literature search in English was performed
using the National Library of Medicine database
and the following key words: radical prostatectomy,
anatomy, neuro-vascular bundle, cavernous nerves,
fascia, Denonvilliers’ fascia, pelvis anatomy,
rectourethralis muscle, puboperinealis, levator ani
and urinary sphincter. A free-text strategy was applied
without limiting the year of publication. Anatomy text
books were also consulted.
RESULTS & DISCUSSION
Although the anatomical description of the
nerves responsible for erectile function dates back to the
19th century (19), Walsh and colleagues (20) were the
first to introduce the term “bundle” as the macroscopic
landmark to be used intraoperatively to identify and
preserve the cavernous nerves (CN). However, since
then, the terms NVB and cavernous nerves have been
often used interchangeably. More recently, Costello et
al emphasized that interchangeable use of those terms
was no longer appropriate because the “bundles”
contained not only the cavernous nerves but also part
of the neurovascular supply to the rectum, levator ani
muscle, urethra, prostate and seminal vesicles (16).
The NVB are composed of both sympathetic
and parasympathetic fibers coming from the pelvic
plexus (inferior hypogastric plexus). While the
former fibers are mostly responsible for ejaculation
and urinary continence, the latter mostly contribute
to erectile function (21). The pelvic plexus is situated
bilaterally within the fibro-fatty tissue of the lateral
aspect of the rectum at its junction with the urinary
bladder, spreading in a fan-like distribution with up
to 3 cm separating the anterior and posterior most
nerves. Its length is approximately 4 cm. It extends
from the sacrum ventrally as high as the rectovesical
cul-de-sac (21-23). The fibers located on the most
anterior aspect of the pelvic plexus are only millimeters
away from the lateral surfaces of the seminal vesicles,
the bladder neck and the prostate base (24, 25).
Although potential injury to the CN might be possible
in this area, the parasympathetic fibers, ultimately
responsible of erectile function, join the neurovascular
bundle 2 to 3 cm below the junction of the bladder
neck and prostate in a spray-like fashion (26, 27).
The nerves converge at the mid-level of the prostate
only to diverge once again when approaching the
prostate apex (16, 28, 29).
Notwithstanding, some authors describe the
area near the prostatic pedicle (23) and the seminal
vesicles (SV) to be the location where injuries to the
CN occur most frequently (21, 25). Others even
propose sparing the tips of the SVs in highly selected
patients, with very low risk of disease progression, as
SURGICAL ANATOMY OF RADICAL PROSTATECTOMY: PERIPROSTATIC FASCIAL ANATOMY...
a means of obtaining better erectile function results
postoperatively (30). The tips themselves are actually
contained in fascial pockets; the NVB is adherent to
the lateral surface of the SV just distal to the tips.
Studies have shown a high interindividual
variation of the nerve fiber count and distribution
surrounding the prostate (31-33). The bulk of
the neurovascular structures tend to be located
posterolaterally in the majority of patients, but may
not always form a bundle. A significant proportion of
fibers may lie away from the main nerve trunks, along
the lateral and posterior aspects of the prostate (34,
35). Controversy in the literature persists regarding
the role of NVB preservation in recovery of urinary
continence (36-40) (see below)
Having described the location of the CN
in relation to the NVB and periprostatic area,
understanding the location and distribution of the
fascias around the prostate and their relation to the
NVB becomes key to achieve the desired degree of
CN dissection. The following fascias are surgi-cal
landmarks that will help determine the layers that
should be incised in order to remove or preserve
different amounts of cavernous nerve tissue during RP
(41-44). There are 4 main distinct fascias surrounding
the prostate and the NVB: (17) (Figure 1)
257
all surfaces of bladder, prostate, seminal vesicles,
rectum, and pudendal vasculature. Its thickness
varies according to the amount of adipose tissue,
vessels and nerves it contains. The fascial tendinous
arch represents a thickening of parietal and visceral
components of the endopelvic fascia that extends
from the pubovesical (puboprostatic) ligaments to the
ischial spine bilaterally (45) (see below)
However, Myers and colleagues proposed a
simpler definition of endopelvic fascia, a definition
that conforms to the Terminologia Anatomica, 1998
and the preceding Nomina Anatomicas. The fascia
lateral to the fascial tendinous arch is called the
parietal endopelvic fascia, and the fascia medial to it,
as it sweeps over the anterior bladder and underlying
prostate, forms the visceral pelvic fascia (1).
Takenaka and colleagues (17) elegantly
confirmed in cadaveric studies what pioneering open
and laparoscopic prostatectomy surgeons traditionally
preached regarding the correct location to incise the
fascia medial to the fascial tendinous arch in order
to access the lateral aspects of the prostate without
leaving the levator ani fibers bare (3, 42) As depicted
in Figure 1 (shaded area), on some occasions, part
a. Endopelvic fascia, (levator ani fascia lateral to the
fascial tendinous arch).
b. Levator ani fascia (lateral pelvic fascia, as a
remnant of levator ani fascia on the lateral prostate
surface after incising the endopelvic fascia lateral to
the fascial tendinous arch of the pelvis)
c. Prostatic fascia
d. Denonvilliers’ fascia (prostato-seminal vesicular
fascia).
a- Endopelvic fascia:
The endopelvic fascia has two components:
parietal and visceral. The parietal layer (endopelvic
fascia) covers the levator ani lateral to the fascial
tendinous arch of the pelvis (45). Visceral fascia is
any fascia that covers a viscus, namely the fascia
medial to the fascial tendinous arch. This fascia covers
longitudinal smooth muscle of the bladder that forms
a discrete layer covering the entire anterior surface of
the underlying prostate.
According to Villers and colleagues (45), the
visceral pelvic fascia is composed of the connective fatty
tissue and neurovascular supply located underneath
the parietal fasciae. It covers and is adherent to
FIGURE 1. Fascial anatomy of the prostate in mid
prostate axial section. Note the shaded areas often
coalesce and needs to be dissected apart to access
the cul-de-sac where the endopelvic fascia reflects.
The deepest part of the endopelvic fascia is the
location where it should be incised in order to minimize
the risk of leaving levator ani muscles fibers bare. f.
fascia. m. muscle.
258
F. P. Secin y F. J. Bianco.
of the endopelvic fascia embracing the prostate
coalesces with that lying over the levator ani fascia
at its deepest point of reflection. This fusion of layers
needs to be detached for an adequate incision of the
endopelvic fascia. Applying countertraction on the
prostate facilitates identification and dissection of
the contour of fascial reflection where the endopelvic
fascia forms a cul-de-sac between the levator ani
fascia laterally and the prostatic fascia medially
(17). It is easier to identify and correctly incise this
cul-desac when this dissection is initiated close to the
base of the prostate (as opposed to close to the apex)
where the endopelvic fascia seems to be thinner and
the space between levator ani and the prostatic fascia
is wider. Having said that, not all prostates have
prostatic fascia, some just have a pseudocapsule,
and this kind of entry medial to the fascial tendinous
arch risks capsulotomy. (Myers, in press)
over the posterior aspect of the seminal vesicles (SVs)
and prostate to merge in the midline with the perineal
body; (44) (Figure 2) Although macroscopically
single-layered, DF is histologically composed in the
majority of cases, though not always, of 2 layers
that can be distinguished under microscope. Some
authors describe it as multilayered, particularly at its
most distal portion (44, 48, 52). DF often is in intimate
contact with the posterior aspect of the prostate in
the midline (48-52). More laterally, DF continues its
course around the rectum detaching itself from the
posterior aspect of the prostate pseudocapsule, to
form the posterior limit of the aforementioned triangle
(Figure 1). Depending on individual variations, a few
fibers of DF may still be linked in part to the prostate
pseudocapsule in this lateral area (48). DF continues
around the mesorectum, where it may become thin
and interrupted (47).
Levator ani fascia LAF
As an outer periprostatic fascia, LAF
(lateral pelvic fascia) covers the underlying, laterally
distributed levator ani muscle and therefore forms
the lateral boundary of the axial triangular space
occupied by the bulk of the cavernous nerves and
vessels, and varying amounts of fat. The medial and
posterior boundaries of such triangle are formed by
the pseudocapsule of the prostate (covered or not
by the prostatic fascia) and Denonvilliers’ fascia,
respectively (16, 17, 46-48). The LAF extends
posteriorly over the muscle fibers and continues
over the lateral aspect of the rectum to form the socalled pararectal fascia (16, 49, 50) which fuses
posteriorly with the presacral fascia (47) (Figure 1).
As previously mentioned, the LAF is variably adherent
to but not completely fused to the PF, thus, they can
be dissected apart generating a space in between
them, where the endopelvic fascia reflects forming a
cul-de-sac. Opening the endopelvic fascia medial to
this cul-de–sac and the fascial tendinous arch of the
pelvis will leave the levator ani fibers covered by its
own fascia. Occasionally the LAF may be adherent to
the prostato-urethral junction (27).
The origin of DF is controversial. While some
authors support the theory of fusion of the anterior
and posterior sheaths of the embryological cul-desac, other simply propose that DF originates from
condensation of loose areolar tissue (53).
Prostatic fascia (PF)
Beneath the outer, thin LAF fascia, the pros-tate
is variably covered by a second, inner periprostatic
fascia, the prostatic fascia (PF). The PF is fused with the
anterior fibromuscular stroma anteriorly (48), coming
into intimate contact with the prostate pseudocapsule
more laterally. Sometimes, PF is absent (Myers, in
press)
Denonvilliers’ fascia (DF)
Denonvilliers’
fascia
(prostato-seminovesicular fascia) (44, 51) is macroscopically composed
of a single, whitish layer of tissue that extends caudally
The description of the axially oriented,
triangular space containing the bulk of the NVB seems
somewhat simplistic and tries to be more didactic and
reproducible than anatomically realistic. Evidence of
this is the controversy in the literature regarding the
relationship between the LAF, DF and components of
the NVB.
For example, Villers and Myers described
the DF to divide at the posterolateral border of the
prostate into an ante-rior and posterior leaf around
the NVB. While the anterior leaf becomes PF, the
posterior continues its course on the rectum to limit the
triangle posteriorly (47). Based on this description,
they describe three types of NVB dissection: (44,
45)
a. Intrafascial plane: The pseudocapsule of the prostate
is rendered bare of any tissue. The aforementioned
anterior leaf of DF (PF) is left covering the medial
aspect of the NVB.
b. Interfascial plane: In this case, PF remains on the
posterolateral surface of the prostate. The anterior leaf
of DF or PF stays on the prostate side and the medial
aspect of the NVB becomes bare of any fascia. Here,
the likelihood of NVB damage might increase, but
gives the surgeon a safer oncologic margin, especially
at the posterolateral aspect of the prostate.
c. Extrafascial plane: The dissection is carried out
posterior to the NVB and out laterally to the LAF. The
SURGICAL ANATOMY OF RADICAL PROSTATECTOMY: PERIPROSTATIC FASCIAL ANATOMY...
prostate is then removed with all layers of visceral
fibrofatty sheath present on the specimen (wide
resection). The NVBs are excised completely or almost
completely.
Kour-ambas and colleagues (49) differ from
this version in that DF divides laterally into several
laminae and DF in not clearly defined at its lateral
edges. They show some compartmentalization of the
NVB by fascial strands in axial section. They described
that the DF represented the horizontal bar of an Hshaped fascial structure, leaving the prostate anterior
and the rectum posterior. The anterior extension of
the H was represented by the left and right LAF and
the lower parts by the para-rectal fascia (continuation
of LAF). Notwithstanding, there is PF anterior to NVB
and a layer of DF posterior to the NVB, meaning
that their basic scheme is not different from the one
described Villers and Myers. Villers and Myers have
simply tried to simplify without worrying about fascial
stranding within the NVB.
According to Costello and colleagues (16),
the boundaries of the triangular area are not as clear
as previously mentioned. At the junction of the PF, DF
and pararectal fasciae, there are numerous leaves of
fibrous tissue. The posterior and lateral aspects of the
NVB run through these leaves. (compartmentalization)
Denonvilliers’ and pararectal fasciae are separated
from the anterior and lateral surfaces of the rectum
by variable amounts of perirectal adipose tissue
(16).
Most authors seem to agree that there are
anatomical variations regarding the number and
thickness of collagen layers composing the PF and DF
at the posterolateral aspect of the prostate. Similarly,
exact location of NVB can vary, with larger prostate
glands tending to displace the bulk of the NVB more
posteriorly (24, 25). Needless to say, recovery of
erectile function postoperatively will not solely depend
on “anatomical” cavernous nerve preservation, but
also on their functional status (avoidance of traction,
etc.), as well as on other anatomic factors, like
preservation of accessory pudendal arteries (54-58),
age, preoperative erectile function (59) and social
aspects.
The sometimes quoted posterior layer of the
DF in the colorectal literature is in reality the fascia
propria of the rectum (serosa) (60). The mesorectum
represents the fatty layer located between the fascia
propria of the rectum and DF, and this is the plane of
dissection that should be followed during RP in order
to minimize the risk of having a positive surgical
margin at the posterior aspect of the prostate (45,
61, 62). This plane is also commonly followed by
259
colorectal surgeons during rectocolonic resections
(47, 60, 63).
Similarly, the often cited anterior layer of DF
interposed between the posterior bladder neck and
the anterior aspect of the SV and vasa deferentia
corresponds in fact to Gil Vernet’s posterior longitudinal
fibers of the detrusor running in between and behind
the ureteral orifices (called vesicoprostatic muscle by
Dorschner and colleagues, m. vesicoprostaticus,TA)
(64-68). This posterior longitudinal fascia of the
prostate is covered by the bladder adventitia on
the outside (65, 68, 69). Vesical remnants of these
posterior longitudinal fibers of the detrusor are what
Rocco and colleagues seem to use to fixate DF during
their posterior reconstruction of the rhabdosphincter
right before performing the urethrovesical anastomosis
(70, 71). There is controversy in the literature
regarding the justification and effectiveness of this
technique (72, 73) (see below)
Prostate Pseudocapsule:
As often taught to us by pathologists, the
prostate has no real capsule. The outermost part of
the prostate is often composed of variable layers
of condensed fibro muscular fascicles inseparable
from the prostatic stroma. This pseudocapsule (46) is
almost absent at the anterior aspect of the prostate,
where the anterior fibromuscular stroma is identified.
(Figure 1) In addition, the pseudocapsule is absent
at the apex of the gland and at the prostate base,
where the gland fuses with the urinary sphincter and
the bladder neck, respectively (48). With respect to
the lateral surfaces of the prostate, there are prostates
with capsule but no PF, and prostates with PF and no
capsule with a range of intermediate forms. (Myers,
in press.)
It would be difficult to recommend defined
areas in which a surgeon should predominantly focus
on nerve preservation. Based on the aforementioned
anatomic landmarks, some surgeons have proposed
a high release of the fascia on the lateral surface of
the prostate in highly selected patients resulting in
improved erectile function recovery postoperatively
(24, 74-78). The objective is to preserve as many
nerve fibers as possible (25, 26, 79). Postoperative
potency might improve with the increas-ing number of
preserved nerve fibers; nonetheless, this is a surgical
option that can compromise the cancer operation as
it may cause a positive surgical margin (74).
Special care should be applied to the apical
region, where injuries to the NVB are not infrequent.
In this area, the NVB is located only millimeters away
from the posterolateral aspect of the membranous
urethra and prostate apex bilaterally (25) (Figure 3).
260
F. P. Secin y F. J. Bianco.
That is the reason why early release of the NVB can
help minimize risk of traction injury (74-76).
Urinary sphincter
The external (as opposed to the bladder
neck internal sphincter) urinary sphincter is another
structure, which might be damaged during RP with
potential deleterious consequences to postoperative
recovery of urinary continence and quality of life.
Therefore, detailed knowledge of its anatomy and
function becomes essential to obtain acceptable
postoperative continence results.
Koraitim recently made a thorough review
of the anatomy and physiology of the male urethral
sphincter (80) The urethral sphincter is composed of
2 morphologically related but, possibly, functionally
unrelated components that extend in the form of a
cylinder around the urethra from the bladder neck to
the distal end of the membranous urethra: (1, 32, 64,
81-84) (Table and Figures 2 & 3)
1- Intrinsic smooth muscle sphincter or lissosphincter:
It is composed of an inner layer of smooth
involuntary muscle that has its main part at the
bladder neck and is thinner in its further course in
the urethra. It forms a complete cylinder of circular
muscle fibers around the urethra, and lies between
the urethral mucosa and the striated external urethral
muscle, making up with the connective and elastic
tissue the bulk of the urethral wall (Figure 3). It
consists of a distinct layer of longitudinal smooth
muscle surrounded by a wider layer of circular smooth
muscle. The lissosphincter maintains continence at rest
by contraction of its circular muscle fibers, resulting in
FIGURE 2. Relation of the pelvic structures in a prostate
sagittal section. f. fascia. m. muscle.
closure of the vesical orifice and concentric narrowing
of the posterior urethra. Maximum closure may be
assumed to be at the level of the vesical orifice, where
the lissosphincter is thickest (85), and in the membranous
urethra, where the urethra is most narrow. Contraction
of the longitudinal fibers widens the urethra during
the evacuation of urine. Complete preservation is not
necessary for continence, as passive continence may
be accomplished by preserving a minimal length of
smooth muscle sphincter postoperatively. This could
be the rationale for better continence results after RP
described in patients with longer membranous urethra
(86).
2-External
striated
urethral
sphincter
or
rhabdosphincter:
It is composed of the outer layer of probably
involuntary, predominantly slow-twitch, fine-fibered
striated muscle (as opposed to coarse-fibered, fasttwitch, voluntary skeletal muscle), which is most
marked and thickest around the membranous
urethra, and becomes gradually less distinct toward
the bladder (Figures 2 & 3). From the perineal
body to the prostatic apex the striated muscle fibers
unite behind the urethra in a central fibrous raphe
(81), while more proximal they form a cap on the
anterolateral side of the prostate. (Figure 3) While
anatomically indivisible, the rhabdosphincter consists
of two functionally distinct components:
a- Ventral fibers extending cephalad over the prostatic
urethra.
b- Caudal fibers extending over the membranous
urethra.
FIGURE 3. Axial section of the sphincteric urethra. f.
fascia. m. muscle.
SURGICAL ANATOMY OF RADICAL PROSTATECTOMY: PERIPROSTATIC FASCIAL ANATOMY...
a- This muscle has to relax to allow semen to
enter the bulbous portion of the urethra so that the
bulbospongiosus muscle (once called the ejaculator
urethrae) can ejaculate the semen.
b- While controversial, the more caudal muscle fibers
of the rhabdosphincter, composed of mixed slow
and maybe fast twitch striated fibers (87, 88), may
be responsible for active urinary continence as they
contract against a fixed posterior median raphe,
resulting in collapse of the anterior urethral wall
against the posterior wall. In addition, it is speculated
that both Denonvilliers’ fascia and the rectourethralis
muscle might form a rigid posterior plate against
which compression of the anterior urethral wall
might increase the surface area of coaptation; thus,
creating a higher urethral resistance (89). This could
explain, in part, the improvements in shortening
time to continence found in patients undergoing the
so-called “Rocco stitch” (70-72, 90). Nonetheless,
other authors did not find this technical modification
useful, although it can be argued that they possibly
did not reproduce exactly the posterior urethral plate
reconstruction described originally (73).
Rocco and colleagues believe, “Denonvilliers’
fascia, and the dorsal aspect of the prostate, acts as a
suspensory system for the prostatomembranous urethra
and that its division during radical prostatectomy
results in the loss of the posterior cranial insertion of the
sphincter, the caudal displacement of the sphincteric
complex, and a prolapse of the perineum” during this
posterior reconstruction (71).
From the embryological point of view, DF
is a remnant barrier between the urinary tract and
the terminal portion of the digestive system (50, 91).
The so called “prolapse of the perineum” may be
more of a visual artifact and a function of increased
intraperitoneal pressure than a real function of DF
sectioning. Pulling on the prostate while sectioning
the urethra and distal attachments of DF, makes the
surgeon believe that the extraprostatic section of the
membranous urethra is longer (or more intrapelvic)
than it actually is (92). Actually, it can be hypothesized
that excessive pulling from the prostate can tear some
sphincteric muscle fibers impacting negatively on
adequate postoperative function. It can be clearly
observed during laparoscopic or robotic RP that
the urethra retracts on its own after being sectioned
despite the distal attachment of DF remaining uncut.
Sectioning this last attachment has no impact on
urethral retraction or on its elastic length.
The urethra is supported anteriorly and
laterally, but there is no anatomic evidence that it
is supported cranially by any structure other than,
possibly, the prostate (1). Burnett and Mostwin
(81) described the male urethral sphincter complex
as consisting of the prostatomembranous urethra,
periurethral musculature (rhabdosphincter), extrinsic
paraurethral musculature and connective tissue
structures of the pelvis. There is a ligamentous
framework supporting the rhabdosphincter mostly
composed of the pubourethral ligaments anteriorly
(most distal part of the pubovesical ligament or
vesical apron), the ischioprostatic ligaments (Mueller’s
TABLE I. COMPARISON BETWEEN LISSOSPHINCTER AND RHABDOSPHINCTER CHARACTERISTICS
OF THE MALE URETHRA.
Lissosphincter
Rhabdosphincter
Control
Involuntary
Voluntary? (Controversial)
Location
Inner
Outer
Distribution
Thicker at the bladder orifice
Thicker at the membranous urethra
Components
Smooth muscle, inner longitudinal layer
Striated muscle, single unit composed of
covered by an outer circular layer
urethral and prostatic fibers
Function
Passive continence
Active continence ? (Controversial)
Modifications with
Does not change
Atrophy of prostatic and membranous
urethral components
age
Changes with BPH
None
261
Yes
262
F. P. Secin y F. J. Bianco.
ligaments) (1) and the medial fascia of the levator
ani, laterally. The dorsal fixation of the membranous
urethra is subject of controversy. We believe the midline
fibrous raphe inserts into the perineal body (81), and
not into the rectourethralis muscle as described by
others. Porzionato and colleagues (93) corroborated
prior observations (94) that muscle fibers along the
anterior aspect of the rectourethralis muscle did not
reach the posterior wall of the membranous urethra.
The mean distance between the rectourethralis muscle
and the membranous urethra was 5.3 mm in adults,
and 1.0 mm in infants (27, 95, 96). Therefore,
DF seems unlikely to exert cephalic support of the
urethra. In the same way, Soga and colleagues (27)
warn against the risks of nerve injury during posterior
reconstruction of the retrourethral plate described by
Rocco (70, 71).
The urethral sphincter is innervated by
branches of the pudendal nerve and by autonomic
branches of the pelvic plexus, which partly run with
the NVB (25, 97-100). Takenaka recently estimated a
3–13 mm distance from the prostatic apex to the point
where the nearest pudendal neural branch enters the
sphincter (17, 84). Con-servation of these branches
may improve postoperative urinary continence, (82),
thus, it seems important to limit the distal dissection
of the mem-branous urethra. Nerve fibers of the NVB
enter the urethra at the 3 and 9 o’clock position
(101). There is controversy in the literature in relation
to the role of NVB preservation in recovery of urinary
continence. (36, 39, 102). Although it is unclear
whether preservation of the neurovascular bundles
themselves or the meticulous dissection required
to dissect the nerves from the apex of the prostate
is responsible for the improvement in continence
after `nerve-sparing’ surgery, every effort should
be made to preserve those nerve fibers as long as
oncologic safety is not compromised. Careful control
of the DVC is key to obtaining a bloodless field and
achieving adequate visualization of the prostato- urethral junction and the posterolateral NVB structures.
Injuries to the NVB might be caused by direct trauma,
NVB traction or by accidentally including the NVB in
sutures during the ligation of the DVC or during the
urethral anastomosis (4, 103).
CONCLUSION
Anatomy of the prostate is complex and can
show individual variations, which adds to the technical
difficulties of radical prostatectomy. Understanding of
the periprostatic fascial anatomy is key to achieving
optimal resection of the prostate gland and seminal
vesicles with negative surgical margins in order to
maximize the chances of cancer control. Pre-cise
preservation of the urethral sphincter and its autonomic
innervation will result in good postoperative urinary
continence results. Early recovery of erectile function
postoperatively will depend both on the anatomical and
functional preservation of the neurovascular structures
and accessory pudendal arteries surrounding the
prostate in properly selected patients. Intraoperative
recognition of the periprostatic vasculature will help
decrease blood loss and reduce the chances of having
perioperative complications.
ACKNOWLEDGEMENTS
The author would like to thank Dr. Luis A.
Aponte Tinao for his help and support. This manuscript
has been supported in part by Coloplast of Argentina
SA and Gobbi Novag SA. The first author would like
to thank Prof. Dr. Robert P. Myers for his invaluable
teaching and support.
REFERENCES AND RECOMENDED READINGS
(*of special interest, **of outstanding interest)
**1. Myers R P. Male urethral sphincteric anatomy and
radical prostatectomy. Urol Clin North Am, 1991;
18: 211.
**2. Bill-Axelson A, Holmberg L, Ruutu M. et al. Radical prostatectomy versus watchful waiting in
early prostate cancer. N Engl J Med, 2005; 352:
1977.
**3. Ohori M, Scardino P T. Localized prostate cancer.
Curr Probl Surg, 2002; 39: 833.
**4. Catalona W J, Carvalhal G F, Mager D E, et al.
Potency, continence and complication rates in
1,870 consecutive radical retropubic prostatectomies. J Urol, 1999; 162: 433.
**5. Hull G W, Rabbani F, Abbas F. et al. Cancer control with radical prostatectomy alone in 1,000
consecutive patients. J Urol, 2002; 167: 528.
**6. Michl U H, Friedrich M G, Graefen M, et al.
Prediction of postoperative sexual function after
nerve sparing radical retropubic prostatectomy. J
Urol, 2006; 176: 227.
**7. Roehl K A, Han M, Ramos C G, et al. Cancer progression and survival rates following anatomical
radical retropubic prostatectomy in 3,478 consecutive patients: long-term results. J Urol, 2004;
172: 910.
8. Touijer K, Romero Otero J, Secin F P et al. 750
Radical prostatectomy: a non-randomized comparative analysis of outcomes between the open
and laparoscopic approach. European Urology
Supplements, 2007; 6: 210.
263
9. Rassweiler J, Seemann O, Schulze M, et al. Laparoscopic Versus Open Radical Prostatectomy:
A Comparative Study at a Single Institution. The
Journal of Urology, 2003; 169: 1689.
10. Rassweiler J, Stolzenburg J, Sulser T, et al. Laparoscopic Radical Prostatectomy - the Experience
of the German Laparoscopic Working Group. European Urology, 2006; 49: 113.
11. Menon M, Tewari A, Peabody J O, et al. Vattikuti
Institute prostatectomy, a technique of robotic
radical prostatectomy for management of localized carcinoma of the prostate: experience of over
1100 cases. Urologic Clinics of North America,
200431: 701.
12. Palmer K J, Shah K, Thaly R. et al. MP-18.04:
Robotic-assisted laparoscopic radical prostatectomy: perioperative outcomes of 1500 consecutive cases. Urology, 2007; 70: 136.
13. Smith J J A. Robotically assisted laparoscopic
prostatectomy: An assessment of its contemporary role in the surgical management of localized
prostate cancer. The American Journal of Surgery,
2004; 188: 63.
14. Ficarra V, Novara G, Artibani W, et al. Retropubic, Laparoscopic, and Robot-Assisted Radical
Prostatectomy: A Systematic Review and Cumulative Analysis of Comparative Studies. Eur Urol,
2009.
**15. Myers R P. Practical surgical anatomy for radical prostatectomy. Urol Clin North Am, 2001; 28:
473.
**16. Costello A J, Brooks M, Cole O J. Anatomical studies of the neurovascular bundle and cavernosal
nerves. BJU Int, 2004; 94: 1071,
**17. Takenaka A, Hara R, Soga H, et al. A novel technique for approaching the endopelvic fascia
in retropubic radical prostatectomy, based on an
anatomical study of fixed and fresh cadavers. BJU
Int, 2005; 95: 766.
**18. Walz J, Graefen M, Huland H. Basic principles of
anatomy for optimal surgical treatment of prostate
cancer. World J Urol, 2007; 25: 31.
19. Eckhardt C. Untersuchungen uber die Erektion
des Penis beim Hunde. Beitr.Anat. Physiol, 1863;
3: 123.
**20. Walsh P C, Lepor H, Eggleston J C. Radical prostatectomy with preservation of sexual function:
anatomical and pathological considerations. Prostate, 1983; 4: 473.
21. Mauroy B, Demondion X, Drizenko A, et al. The
inferior hypogastric plexus (pelvic plexus): its importance in neural preservation techniques. Surg
Radiol Anat, 2003; 25: 6.
**22. Lepor H, Gregerman M, Crosby R, et al. Precise localization of the autonomic nerves from the
pelvic plexus to the corpora cavernosa: a detailed
anatomical study of the adult male pelvis. J Urol,
1985; 133: 207.
**23. Walsh P P C, Donker P P J. Impotence following
radical prostatectomy: insight into etiology and
prevention. The Journal of urology, 1982; 128:
492.
24. Lunacek A, Schwentner C, Fritsch H, et al. Anatomical radical retropubic prostatectomy: ‘curtain
dissection’ of the neurovascular bundle. BJU Int,
2005 95: 1226.
25. Takenaka A, Murakami G, Matsubara A, et
al.Variation in course of cavernous nerve with
special reference to details of topographic relationships near prostatic apex: histologic study using
male cadavers. Urol, 2005; 65: 136.
26. Takenaka A, Murakami G, Soga H, et al. Anatomical analysis of the neurovascular bundle supplying penile cavernous tissue to ensure a reliable nerve graft after radical prostatectomy. J Urol,
2004; 172: 1032.
27. Soga H, Takenaka A, Murakami G, et al. Topographical relationship between urethral rhabdosphincter and rectourethralis muscle: a better
understanding of the apical dissection and the
posterior stitches in radical prostatectomy. Int J
Urol, 2008; 15: 729.
28. Costello A J. Editorial Comment. The Journal of
Urol, 2007; 177: 1770.
**29. Walsh P C. Anatomical studies of the neurovascular bundle and cavernosal nerves. J Urol, 174:
566, 2005
30. Zlotta A R, Roumeguere T, Ravery V, et al. Is seminal vesicle ablation mandatory for all patients
undergoing radical prostatectomy? A multivariate analysis on 1283 patients. Eur Urol, 2004; 46:
42.
31. Eichelberg C, Erbersdobler A, Michl U, et al. Nerve distribution along the prostatic capsule. Eur
Urol, 2007; 51: 105.
32. Ganzer R, Blana A, Gaumann A, et al. Topographical anatomy of periprostatic and capsular nerves: quantification and computerised planimetry.
Eur Urol, 2008; 54: 353.
33. Sievert K D, Hennenlotter J, Laible I, et al. The
periprostatic autonomic nerves--bundle or layer?
Eur Urol, 2008; 54: 1109.
34. Raychaudhuri B, Cahill D. Pelvic fasciae in urology. Ann R Coll Surg Engl, 2008; 90: 633.
35. Kaiho Y, Nakagawa H, Saito H, et al. Nerves at
the Ventral Prostatic Capsule Contribute to Erectile Function: Initial Electrophysiological Assessment in Humans. Eur Urol, 2008.
36. Eastham J A. Does neurovascular bundle preservation at the time of radical prostatectomy improve urinary continence? Nat Clin Pract Urol, 2007;
4: 138.
37. Stolzenburg J U, Liatsikos E N, Rabenalt R, et
al. Nerve Sparing Endoscopic Extraperitoneal
264
38.
39.
40.
41.
42.
43.
**44.
**45.
**46.
47.
48.
49.
**50.
**51.
Radical Prostatectomy- Effect of Puboprostatic
Ligament Preservation on Early Continence and
Positive Margins. Europ Urol, 2006; 49: 103.
Eastham J A, Kattan M W, Rogers E, et al. Risk
factors for urinary incontinence after radical prostatectomy. J Urol, 1996; 156: 1707.
Marien T P, Lepor H. Does a nerve-sparing technique or potency affect continence after open
radical retropubic prostatectomy? BJU Int, 2008;
102: 1581.
Burkhard F, Kessler T, Fleischmann A, et al.
Nerve sparing open radical prostatectomy-does
it have an impact on urinary continence? J Urol,
2006; 176: 189.
Secin F P, Serio A, Bianco J F J, et al. Preoperative
and Intraoperative Risk Factors for Side-Specific
Positive Surgical Margins in Laparoscopic Radical Prostatectomy for Prostate Cancer. European
Urol, 2007; 51: 764.
Secin F P, Touijer K, Karanikolas N T, et al. Laparoscopic Radical Prostatectomy: Lessons Learned in Surgical Technique. Eur Urol Sup, 2006;
5: 942.
Stolzenburg J U, Schwalenberg T, Horn L C, et al.
Anatomical landmarks of radical prostatecomy.
Eur Urol, 2007; 51: 629.
Myers RP, Villers A. Prostate cancer: principles
and practice. London: Taylor & Francis, 2006; pp.
701 -713.
Villers A, Piechaud T. Surgical Anatomy of the
Prostate for Radical Prostatectomy: Springer Berlin Heidelberg, 2008; pp. 11-18.
Myers R P. Detrusor apron, associated vascular
plexus, and avascular plane: relevance to radical
retropubic prostatectomy--anatomic and surgical
commentary. Urol, 2002; 59: 472.
Ayala A G, Ro J Y, Babaian R, et al. The prostatic
capsule: does it exist? Its importance in the staging and treatment of prostatic carcinoma. Am J
Surg Pathol, 1989; 13: 21.
Kinugasa Y, Murakami G, Uchimoto K, et al.
Operating behind Denonvilliers’ fascia for reliable preservation of urogenital autonomic nerves
in total mesorectal excision: a histologic study
using cadaveric specimens, including a surgical
experiment using fresh cadaveric models. Dis Colon Rectum, 2006; 49: 1024.
Kiyoshima K, Yokomizo A, Yoshida T, et al. Anatomical features of periprostatic tissue and its surroundings: a histological analysis of 79 radical
retropubic prostatectomy specimens. Jpn J Clin
Oncol, 2004; 34: 463.
Kourambas J, Angus D G, Hosking P, et al. A histological study of Denonvilliers’ fascia and its relationship to the neurovascular bundle. Br J Urol,
1998; 82: 408.
van Ophoven A, Roth S. The anatomy and embr-
**52.
53.
54.
55.
56.
57.
58.
59.
**60.
**61.
**62.
63.
64.
65.
66.
67.
yological origins of the fascia of Denonvilliers: a
medico-historical debate. J Urol, 1997; 157: 3.
Denonvilliers C. Propositions et observation
d’anatomie, de physiologie at de pathologie. These de l’Ecole de Medicine, 1837; 285: 23.
Fritsch H, Lienemann A, Brenner E, et al. Clinical
anatomy of the pelvic floor. Adv Anat Embryol
Cell Biol, 2004; 175: III.
Silver P H. The role of the peritoneum in the formation of the septum recto-vesicale. J Anat, 1956;
90: 538.
Matin S F. Recognition and preservation of accessory pudendal arteries during laparoscopic radical
prostatectomy. Urol, 2006; 67: 1012.
Secin F P, Touijer K, Mulhall J, et al. Anatomy
and Preservation of Accessory Pudendal Arteries
in Laparoscopic Radical Prostatectomy. European
Urol, 2007; 51: 1229.
Nehra A, Kumar R, Ramakumar S, et al. Pharmacoangiographic evidence of the presence and
anatomical dominance of accessory pudendal
artery(s). J Urol, 2008; 179: 2317.
Polascik T J, Walsh P C. Radical retropubic prostatectomy: the influence of accessory pudendal
arteries on the recovery of sexual function. J Urol,
1995; 154: 150.
Mulhall J P, Secin F P, Guillonneau B. Artery
sparing radical prostatectomy--myth or reality? J
Urol, 2008; 179: 827.
Rabbani F, Stapleton A M, Kattan M W, et al. Factors predicting recovery of erections after radical
prostatectomy. J Urol, 2000; 164: 1929.
Lindsey I, Guy R J, Warren B F, et al. Anatomy of
Denonvilliers’ fascia and pelvic nerves, impotence, and implications for the colorectal surgeon. Br
J Surg, 2000; 87: 1288.
Villers A, McNeal J E, Freiha F S, et al. Invasion
of Denonvilliers’ fascia in radical prostatectomy
specimens. J Urol, 1993; 149: 793.
Dumonceau O, Delmas V, Toublanc M, et al. [Innervation of Denonvilliers’ recto-vesical fascia.
Anatomical study]. Prog Urol, 2000; 10: 53.
Aigner F, Zbar A P, Ludwikowski B, et al. The
rectogenital septum: morphology, function, and
clinical relevance. Dis Colon Rectum, 2004; 47:
131.
Dorschner W, Stolzenburg J U. A new theory
of micturition and urinary continence based on
histomorphological studies. 3. The two parts of
the musculus sphincter urethrae: physiological
importance for continence in rest and stress. Urol
Int, 1994; 52: 185.
Secin F P, Karanikolas N, Gopalan A, et al. The
anterior layer of Denonvilliers’ fascia: a common
misconception in the laparoscopic prostatectomy
literature. J Urol, 2007; 177: 521.
Dorschner W, Stolzenburg J U, Dieterich F. A new
265
68.
**69.
70.
**71.
72.
73.
74.
75.
**76.
77.
78.
79.
80.
theory of micturition and urinary continence based
on histomorphological studies. 2. The musculus
sphincter vesicae: continence or sexual function?
Urol Int, 1994; 52: 154.
Cupedo R N. The ureterovesical junction and
the musculature of the dorsal wall of the urinary
bladder. Acta Anat (Basel), 1974; 89: 516.
Gil Vernet S. Morphology and Function of Vesico-Prostato-Urethral Musculature. Treviso, 1968;
p. 334.
Hutch J A, Ayres R D, Loquvam G S. The bladder
musculature with special reference to the ureterovesical junction. J Urol, 1961; 85: 531.
Rocco B, Gregori A, Stener S, et al. Posterior Reconstruction of the Rhabdosphincter Allows a Rapid Recovery of Continence after Transperitoneal
Videolaparoscopic Radical Prostatectomy. Eur
Urol, 2007; 51: 996.
Rocco F, Carmignani L, Acquati P, et al. Early
continence recovery after open radical prostatectomy with restoration of the posterior aspect of
the rhabdosphincter. Eur Urol, 2007; 52: 376.
Nguyen M M, Kamoi K, Stein R J, et al. Early
continence outcomes of posterior musculofascial
plate reconstruction during robotic and laparoscopic prostatectomy. BJU Int, 2008; 101: 1135.
Menon M, Muhletaler F, Campos M, et al. Assessment of early continence after reconstruction
of the periprostatic tissues in patients undergoing
computer assisted (robotic) prostatectomy: results
of a 2 group parallel randomized controlled trial. J
Urol, 2008; 180: 1018.
Eastham J A. Surgery Insight: optimizing open
nerve-sparing radical prostatectomy techniques
for improved outcomes. Nat Clin Pract Urol,
2007; 4: 561.
Klein E A, Kupelian P A, Tuason L, et al. Initial
Dissection of the Lateral Fascia Reduces the Positive Margin Rate in Radical Prostatectomy. Urol,
1998; 51: 766.
Masterson T A, Serio A M, Mulhall J P, et al. Modified technique for neurovascular bundle preservation during radical prostatectomy: association
between technique and recovery of erectile function. BJU Int, 2008; 101: 1217.
Nielsen M E, Schaeffer E M, Marschke P, et al.
High anterior release of the levator fascia improves sexual function following open radical retropubic prostatectomy. J Urol, 2008; 180: 2557.
Menon M, Kaul S, Bhandari A, et al. Potency following robotic radical prostatectomy: a questionnaire based analysis of outcomes after conventional nerve sparing and prostatic fascia sparing
techniques. J Urol, 2005; 174: 2291.
Eichelberg C, Erbersdobler A, Haese A, et al.
Frozen Section for the Management of Intraoperatively Detected Palpable Tumor Lesions During
**81.
**82.
83.
84.
85.
86.
87.
88.
89.
90.
91.
92.
93.
94.
**95.
Nerve-Sparing Scheduled Radical Prostatectomy.
Eur Urol, 2006 49: 1011.
Koraitim M M. The male urethral sphincter complex revisited: an anatomical concept and its physiological correlate. J Urol, 2008; 179: 1683.
Burnett A L, Mostwin J L. In situ anatomical study of the male urethral sphincteric complex: relevance to continence preservation following major
pelvic surgery. J Urol, 1998; 160: 1301.
Karam I, Droupy S, Abd-Alsamad I, et al. The
precise location and nature of the nerves to the
male human urethra: histological and immunohistochemical studies with three-dimensional reconstruction. Eur Urol, 2005; 48: 858.
Koyanagi T. Studies on the sphincteric system located distally in the urethra: the external urethral
sphincter revisited. J Urol, 1980; 124: 400.
Narayan P, Konety B, Aslam K, et al. Neuroanatomy of the external urethral sphincter: implications for urinary continence preservation during
radical prostate surgery. J Urol, 1995; 153: 337.
Nyo M M. The musculature of the human urinary bladder and its sphincters. J Anat, 1969; 105:
191.
Paparel P, Akin O, Sandhu J S, et al. Recovery of
Urinary Continence after Radical Prostatectomy:
Association with Urethral Length and Urethral
Fibrosis Measured by Preoperative and Postoperative Endorectal Magnetic Resonance Imaging.
Eur Urol, 2008.
Elbadawi A, Mathews R, Light J K, et al. Immunohistochemical and ultrastructural study of rhabdosphincter component of the prostatic capsule. J
Urol, 1997; 158: 1819.
Tokunaka S, Murakami U, Fujii H, et al. Coexistence of fast and slow myosin isozymes in human
external urethral sphincter. A preliminary report. J
Urol, 1987; 138: 659.
Lowe B A. Preservation of the anterior urethral
ligamentous attachments in maintaining postprostatectomy urinary continence: a comparative
study. J Urol, 1997; 158: 2137.
Coughlin G, Dangle P P, Patil N N et al. Surgery
Illustrated--focus on details. Modified posterior
reconstruction of the rhabdosphincter: application
to robotic-assisted laparoscopic prostatectomy.
BJU Int, 2008; 102: 1482.
Godlewski G, Prudhomme M. Embryology and
anatomy of the anorectum. Basis of surgery. Surg
Clin North Am, 2000; 80: 319.
Shafik A, Sibai O E, Shafik A A, et al. A novel
concept for the surgical anatomy of the perineal
body. Dis Colon Rectum, 2007; 50: 2120.
Porzionato A, Macchi V, Gardi M, et al. Histotopographic study of the rectourethralis muscle.
Clin Anat, 2005; 18: 510.
Myers R P, Cahill D R, Devine R M, et al. Ana-
266
96.
97.
98.
99.
tomy of radical prostatectomy as defined by
magnetic resonance imaging. J Urol, 1998; 159:
2148.
Sebe P, Oswald J, Fritsch H, et al. An embryological study of fetal development of the rectourethralis muscle--does it really exist? J Urol, 2005;
173: 583.
Uchimoto K, Murakami G, Kinugasa Y, et
al.Rectourethralis muscle and pitfalls of anterior
perineal dissection in abdominoperineal resection
and intersphincteric resection for rectal cancer.
Anat Sci Int, 2007; 82: 8.
Steiner M S. Continence-preserving anatomic radical retropubic prostatectomy. Urol, 2000; 55:
427.
Strasser H, Bartsch G. Anatomy and innervation
of the rhabdosphincter of the male urethra. Semin
Urol Oncol, 2000; 18: 2.
100. Tanagho E A, Schmidt R A, de Araujo C G. Urinary striated sphincter: what is its nerve supply?
Urol, 1982; 20: 415.
101. Hollabaugh R S, Jr, Dmochowski R R, Steiner M
S. Neuroanatomy of the male rhabdosphincter.
Urol, 1997; 49: 426.
102. Baader B, Herrmann M. Topography of the pelvic autonomic nervous system and its potential
impact on surgical intervention in the pelvis. Clin
Anat, 2003; 16: 119.
103. KaihoY, Nakagawa H, Ikeda Y, et al. Intraoperative electrophysiological confirmation of urinary
continence after radical prostatectomy. J Urol,
2005;173: 1139.
104. Graefen M, Michl U H G, Heinzer H, et al. Indication, Technique and Outcome of Retropubic Nerve-Sparing Radical Prostatectomy. EAU Update
Series, 2005; 3: 77.