Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5514_Библиотеки_им_академика_М_И_Перельмана.pdf
7 The Modern Staged Repair ofClassic Bladder Exstrophy
105
cord insertion on both fUS and fMRI was prudent to differentiate between CBE and
CE given the abdominal wall defects.
The importance of a correct and early prenatal diagnosis cannot be overstated. In
the largest single institution series on prenatal diagnosis of CE to date assessing fUS
trends, Morrill and colleagues found a 78.6% rate of prenatal diagnosis (n=44),
while 21.4% (n=12) were diagnosed postnatally [6]. Importantly, patients diagnosed prenatally were more likely to undergo closure at exstrophy centers of excellence (72.1% vs. 33.3%, p=0.020), and primary closures that occurred at these
specialized centers were signicantly more likely to be successful compared to outside hospitals without the designation (90.9% vs. 50.0%, p=0.002). Similar ndings parallel this data in unpublished but presented data for CBE as well [2].
Anatomic Anomalies
Bony Pelvis andPelvic Floor Considerations
Anomalies of the bony pelvis and the requisite pubic diastasis are the hallmark of
EEC.Utilizing three-dimensional (3D) computed tomography (CT) of the bony pelvis in exstrophy patients and elucidating abnormalities, Sponseller etal. modernized our understanding of the characteristic widening of the pubic symphysis. Most
notably, two broad categories of abnormalities were identied—rotational and
dimensional anomalies (Table7.1) [7]. Compared to age-matched controls, in CBE,
the posterior pelvis is externally rotated an average of 12 degrees on each side,
while the anterior pelvis is externally rotated an average of 18 degrees. Added to this
rotational difference, the pubic rami are 30% shorter, which, combined with a retroverted acetabulum, leads to an average diastasis of 4.8 centimeters (cm) in
CBE.These defects are even more exaggerated in CE patients, with an overall 43%
decrease in bony length in the entire pelvis, with an average pubic diastasis greater
than 6cm and an increased likelihood of asymmetry between the right and left sides
of the pelvis [7]. For clarity, mild diastasis is less than 4cm, moderate diastasis is
between 4 and 6cm, and extreme diastasis is anything >6cm.
Table 7.1 Anomalies of the exstrophy pelvis
Rotational Dimensional
External rotation of the posterior pelvis/iliac
wings
External rotation of the anterior pelvic segment Shortened anterior pubic segment (30%)
Coronal rotation of the sacroiliac joint Increased intertriradiate cartilage distance
Acetabular retroversion
Convergence of iliac wings
Femoral retroversion
Increased pubic diastasis
106
C. B. Crigger and J. P. Gearhart
The rotational and dimensional anomalies of the aforementioned bony pelvis
directly impact the maldevelopment of the pelvic oor. Pelvic oor 3D-CT imaging
of children with exstrophy revealed that the levator ani muscles are positioned more
posteriorly (68% posteriorly/32% anteriorly) compared to age-matched controls
(52% posteriorly/48% anteriorly) [8]. In addition to being more posteriorly oriented, the levator ani is also less concave. Another consequence of the bony pelvis
deformities manifested in the pelvic oor is the more attened puborectalis compared to its usual conical shape. The paucity of anterior pelvic oor musculature and
the lack of a conical shape drive the surgical technique in reconstructing the bony
pelvis and pelvic oor, which positions the posterior urethrovesical unit deep within
the pelvis. This technique is discussed separately below.
It is critical to have a clear understanding of all anatomic anomalies prior to closure, particularly with CE, given the multitude of major multisystem defects.
Specic commentary on each system impacted is beyond the scope of this chapter;
however, all pressing gastrointestinal, neurological, and genitourinary concerns
should be addressed prior to denitive surgical intervention.
Initial Evaluation andManagement
Typically, the pediatric urology team is at least aware of the child’s arrival, particularly if a prenatal diagnosis was made. However, the diagnosis of EEC alone does
not necessarily require delivery at an exstrophy center of excellence. In the delivery
room, the umbilical cord should be tied with 2–0 silk as close to the abdominal wall
as possible rather than occluding it using the usual umbilical stump clamps. It is
important to remember that the exposed bladder mucosa is usually pink and smooth
but friable. Minimizing trauma—using silk suture to occlude the umbilical stump,
for instance—will help protect the delicate mucosa from undue trauma or excoriations and the development of bladder polyps. Keeping the bladder moist with sterile
saline irrigation and covering the bladder mucosa using non-adhesive lm such as
Saran Wrap can prevent abrasions from the diaper and the mucosa from drying out.
Such care can be performed at each diaper change.
Determining Suitability forImmediate Closure
Successful closure relies on careful assessment of the size and potential functional
capacity of the detrusor muscle. Often, examination under anesthesia allows full
assessment of the bladder template, free of Valsalva manipulation from the newborn crying or moving. If the child is robust, without any more pressing medical
concerns (rarely the case for CE), then immediate closure within 72h may be
considered in CBE.An ideal bladder template is one that is at least 3×3cm and
free of polyps [9]. Additionally, some conditions may force closure in a delayed
manner, including penoscrotal duplication, ectopic bowel, and signicant bilateral
hydronephrosis.
7 The Modern Staged Repair ofClassic Bladder Exstrophy
107
Regarding pelvic osteotomy—typically, the greater the bladder template, the
wider the resultant diastasis, and the greater the need for osteotomy. Generally, if
closure is attempted within 72h of birth, osteotomy is not required unless diastasis
is over 4cm or the pelvis demonstrates poor malleability [10]. Anatomically, the
inherent laxity of the sacroiliac ligaments in the rst 72h of life allows closure of
the defect without undue tension. If conditions are not perfect or resources cannot
be mobilized quickly enough, then closure should be delayed several weeks to
months to allow optimization of bladder mucosa and surgical teams.
Immediate vs Delayed Closure
Historically, CBE closure occurred as soon as it was safe for the child to undergo
anesthesia, as success rates were deemed better, and due to concerns for poor eventual bladder growth in delayed closure. Recent publications challenge this notion
and reect a greater shift in closure practices.
Baranadan etal. were among the rst to assess the impact of delayed primary
repair of CBE on bladder capacities. The authors evaluated 33 patients who underwent delayed exstrophy closure due to small bladder templates (n=18) or due to
late referral (n=15) and compared outcomes to 82 patients who underwent closure
at a median of 2days of life. The authors found that delayed closures did have
smaller bladder capacities (36 cc smaller in the poor template group and 29cc
smaller in the late referral group), but the rate of bladder growth did not differ [11].
In short, children with smaller templates will have smaller capacities, but the rate of
growth in capacity is not affected. Additionally, children with smaller templates are
less likely to undergo bladder neck reconstruction (BNR) and more likely to need
bladder neck transection (BNT).
With the safety of delaying primary closure to allow a demure bladder template
to grow, without jeopardizing the growth rate, Wu and colleagues sought to determine if a threshold exists beyond which it is too late to delay. The authors assessed
bladder capacities in successful neonatal (e.g., ≤28 days old) or delayed (e.g.,
>28days old) closures. Additionally, time points for closure and bladder capacity
measurements were stratied by quartiles, with the second and fourth quartiles representing 4–6months and beyond 9months, respectively [12]. Based on this, the
authors found that the appropriate time to close an exstrophy patient is as early as
possible (rst quartile) or delayed between 6 and 9months (third quartile), but that
the most signicant declines in capacity occurred at 4–6 months and beyond
9months [12].
Though primary closure can safely be delayed, within reason, the decision to do
so should be approached delicately. With recent trends in exstrophy closure shifting to a more delayed approach with success, associated complication rates
remained unanswered. Ahn etal. (2018) assessed 62 patients who underwent primary exstrophy closure, of which 44 (71%) were delayed. Mean anesthesia and
operative times were greater in the delayed closure group (4–120days of life),
which also had more concurrent procedures (e.g., inguinal hernia repair,
108
osteotomies) compared to early closure (dened as surgery at 0–3days of life).
When comparing 30-day complications, the delayed closure group had a higher
30-day complication rate, mostly due to a greater need for blood transfusion (57%
vs. 11%); however, wound dehiscence also occurred more in the delayed group as
well (6/44, 14% vs. 0/18, 0%). A review of the national data available during the
study period ranging from 1999 to 2010 conrmed a rapid trend toward delayed
closure in this cohort (71% vs. 27%) [13].
C. B. Crigger and J. P. Gearhart
Surgical Reconstruction
Soft Tissue Closure: Bladder, Posterior Urethra,
andAbdominal Wall
Soft tissue reconstruction begins with careful consideration of the bladder and urethral template coupled with the perceived laxity of the abdominal wall. Of note,
preoperative testosterone supplementation is utilized as an adjunct for males to
enhance penile and urethral closure.
Beginning at the level of the anterior superior iliac spine in the midline at the
level of the expected umbilicus, a “V”-shaped incision is made with a midline
extension caudally to the cephalad aspect of the bladder template. The incision is
then carried circumferentially, paralleling the border of the bladder mucosa, taking
great care to not violate or harm delicate mucosa. This is extended caudally along
the inferior aspect of the bladder template until a strip of mucosa 2cm wide is created at the extent of the distal trigone. This strip is continued distally below the
verumontanum to the midshaft of the penis in males, depending on available skin,
or to the level of the vaginal orice in females. In males, the urethral groove and
posterior urethral length may be inadequate, necessitating elevation of paraexstrophy skin aps and transection of the urethral plate for urethral lengthening according to the manner described by Duckett [14–16].
With the template outlined and sharply dissected, a plane is established between
the rectus fascia and the bladder. Gentle blunt dissection, often with a moistened
Kittner, peels the peritoneum off the bladder. This, along with doubly ligating and
dividing the umbilical vessels, allows the bladder to be placed deep within the pelvis without any undue tethering. The created plane is continued caudally, following
the rectus fascia as a guide, until the urogenital diaphragm bers and pubis are
encountered bilaterally. One trick the authors employ is to utilize a double-pronged
wide skin hook and insert it into the bone to apply lateral traction. Doing so accentuates the urogenital diaphragm bers. These bers must be radically dissected, typi-
cally with electrocautery, down to the levator hiatus in the pelvic oor in their
entirety. Failure to fully dissect these bers may result in: (1) a posterior vesicoure-
thral unit that is brought anteriorly into an unsatisfactory position for later CantwellRansley epispadias repair and (2) an increased likelihood of failed primary
closure [14].
7 The Modern Staged Repair ofClassic Bladder Exstrophy
Fig. 7.1 Radical
dissection of urogenital
diaphragm bers.
Complete release of these
pelvic oor bers is
necessary to appropriately
place the posterior
urethrovesical unit and
bladder deep within the
pelvis. Failure to dissect
these bers completely was
shown to increase the
failed closure rate [17]
Urogenital
fibers
dissected
109
The importance of radical dissection of all urogenital diaphragm bers was eloquently demonstrated by Davis etal. in identifying 93 failed primary CBE closures
referred to the authors’ institution (Fig.7.1) [17]. In review of operative notes of the
primary closure, compared to intraoperative ndings during re-closure, urogenital
bers were completely intact bilaterally at the time of repeat closure in 74 patients
(79.6%). Interestingly, no patients had urogenital diaphragm bers intact unilaterally. Similarly, others have utilized the advantages of 3D-MRI imaging preoperatively to assess pelvic oor anatomy, overlayed intraoperatively with BrainLab
(Munich, Germany) to guide intraoperative dissection and ensure complete dissection of urogenital diaphragm bers (Fig.7.2) [18, 19].
With the bladder template dissected freely from all possible tethering tissues, the
mucosa and muscle of the bladder, bladder neck, and urethra are closed, and the
entire unit is easily placed deep within the pelvis. Prior to closure of the bladder,
each ureteral orice is cannulated with a 5 Fr feeding tube that is externalized via a
small window in the dome of the bladder through which the feeding tubes (acting as
urethral stents) and a nonlatex suprapubic Malecot catheter are brought. These tubes
will allow the bladder to heal while continuously draining the bladder of urine.
These various tubes will remain in place until ultrasonography coupled with clamping trials of the suprapubic Malecot demonstrate that they may be safely removed.
This is discussed under postoperative management.
110
Fig. 7.2 MRI-guided anatomic dissection utilizing BrainLab. MRI reconstruction of the pelvic
oor anatomy has shown great promise in guiding anatomic dissection and aiding in successful closure
C. B. Crigger and J. P. Gearhart
Pressure is then applied to the greater trochanters bilaterally, bringing the pubic
bones into midline apposition. A horizontal mattress suture, typically a No. 2 nylon,
is placed at the junction where the rectus fascia inserts onto the dorsal pubic bone,
securing the pubic closure into position (Fig.7.3). The fascia is then closed, and
skin aps are elevated to aid in cosmesis. At the cephalad aspect of the midline incision, prior to closing the fascia entirely, all drainage tubes are brought to the skin
surface. Utilizing the “V”-shaped ap created at the initial midline incision beginning the case, this ap is xed to the abdominal fascia, and formal umbilicoplasty is
performed in the manner described by Hanna [20]. The key steps of soft tissue closure are detailed in Fig.7.4a–h [14].
Soft tissue reconstruction of CE parallels that of CBE.Approximation of the
hemibladders posteriorly converts the defect from CE to CBE.This is achieved by
dissection of the lateral aspects of the bladder halves from the abdominal wall and
closure in the midline [21]. Orthotopic reconstruction via placement of the bladder
and posterior urethra deep into the pelvis remains a crucial factor in successful surgical reconstruction. Approximation of the widened pelvis aids in this goal, permitting abdominal wall and urinary tract reconstruction; however, this usually requires
pelvic osteotomies and xation in a staged fashion, as will be described later in this
chapter.
Unlike in CBE, the large abdominal wall defect found in CE presents a signicant challenge in tension-free abdominal wall reconstruction. Failure to consider
tension at the time of closure may impact rates of successful closure and stula
formation. Bioprosthetic materials such as Alloderm (Allergan, Branchburg, NJ)
have shown great promise in bridging the gap in lack of abdominal wall tissue while
providing a tension-free closure [22]. Additionally, Alloderm has been used as an
innominat
ng
7 The Modern Staged Repair ofClassic Bladder Exstrophy
Fig. 7.3 Pelvic
reconstruction. The
combined posterior vertical
iliac osteotomy and
anterior innominate
osteotomy recongure the
pelvis and aid in soft tissue
closure. At the authors’
institution, it is seen as a
critical adjunct in
successful closures when
utilized
Preclosure
Closure with
osteotomy
Vertical-iliac
osteotomy
Rectum
Bladder
111
Closure
Urethra
Closure without
osteotomy
(a) Approximation of levators
and puborectalis sling
(b) Inclusion of bladder neck
and urethra within pelvic ri
Anterior
osteotomy
adjunct to decrease penopubic stulization through coverage of the interpubic stitch
at the time of urinary tract reconstruction [23].
e
Suture in upper
third of public
bones
The Role ofOsteotomy
As aforementioned, the open pelvic ring is a hallmark of the EEC, and as such,
osteotomy has emerged as a critical factor in successful closure in most children
with CBE and is indicated in all children with CE at the time of bladder closure [14,
24]. Osteotomy corrects the wide pubic diastasis and allows for orthotopic position-
ing of the bladder and posterior urethra as deep as possible within the pelvis while
112
ab
cd
Incision to
midshaft of
penis
C. B. Crigger and J. P. Gearhart
Incision
down to
vaginal os
Incision follows
bladder template
and incorporates
umbilicus
Later aspect
of bladder
dissected
Fig. 7.4
(a–h) Soft tissue reconstruction in MSRE. Complete mobilization of the bladder so that
the bladder may be closed without undue tension
Urachal
remnant
used for
retraction
7 The Modern Staged Repair ofClassic Bladder Exstrophy
113
ef
Ant. rectus
sheath
Symphysis
pubis
Crura is dissected
and visualized
completely
Divided
suspensory
ligament
Malecot
catheter
Ureteral
stents
UG diaphragm
incised to level
of levator hiatus
gh
Catheter and stents
exit via neoumbilicus
Rectus fascia
is reapproximated
Symphysis
sutured using
No. 2 nylon
Bladder neck
and posterior
urethral opening
tapered over
12-Fr sound
Fig. 7.4 (continued)
Bladder wall
is closed
114
C. B. Crigger and J. P. Gearhart
also facilitating bladder and abdominal wall reconstruction with minimal tension.
Reducing undue tension correlates with improved outcomes, mainly decreased rates
of dehiscence and postoperative ventral hernias. Additionally, osteotomy in the CE
patient has been found to reduce the likelihood of signicant complications from
89% in patients closed without osteotomy to 17% in children closed with osteotomy
[25]. This was conrmed in a large series of 80CE patients that reported 91% successful exstrophy repairs with osteotomy performed at the time of closure [26].
Finally, osteotomy allows repositioning of the pelvic oor musculature more anteriorly to support the bladder neck and potentially aid in eventual urinary control in
epispadias and CBE patients.
The timing of osteotomy is critical. In CBE patients younger than 72h old, if
examination under anesthesia demonstrates malleable pubic bones that are easily
brought to the midline, the patient may undergo closure without osteotomy, but with
appropriate postoperative immobilization. Beyond this age, combined osteotomies
(as described below) are recommended. Osteotomies are also recommended for
pubic diastasis greater than 4cm, even if closure is planned before 72h of life, and
should be mandated in all CE closures [14].
Though several types of pelvic osteotomies exist, the combined bilateral anterior
innominate and posterior vertical iliac osteotomies are the preferred method at the
authors’ institution and are coordinated with bladder closure at the time of CBE
closure, or in an approach coined the Dual-Staged Pathway (DSP) for CE [27, 28].
A benet of the combined osteotomy in the supine position is the added benet of
not needing to reposition the patient prior to bladder and abdominal wall closure.
Avoiding a posterior approach reduces the risk of damaging any spinal or neurovascular structures. Additionally, in CE, pelvic osteotomies allow gradual pelvic reduction with external xation 2–3weeks prior to bladder and abdominal wall closure
(DSP). This is often utilized in instances of extremely wide pubic diastasis (>10cm)
and was even successfully used in one patient with a pubic diastasis of 16cm [27].
At the authors’ institution, external xation and modied Buck’s traction are maintained for 4weeks in CBE closures and 6weeks in CE closures to ensure adequate
healing. In our experience, this immobilization technique provides exceptional
results with a 3.8% failure rate in primary closures, compared to 65.7% for immobilization with a spica cast [29].
Trends in osteotomy use for CE closures have drastically changed in the
post-1990, or “modern,” era of exstrophy. Haney etal. found that the combined
osteotomy approach has increased in prevalence over time, with the posterior
approach signicantly decreasing [30]. Additionally, lower limb immobilization has
increased overall, with Buck’s traction becoming the most common. Finally, multistaged procedures have increased over time while single-staged approaches have
signicantly decreased (Table7.2).