Bladder and Cloacal Exstrophy
The exstrophy–epispadias complex (EEC) is a spectrum of embryological abnormalities. Diagnoses within the EEC range in severity from those involving only one organ to others that are a part of a larger complex of defects. The spectrum includes:
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Epispadias—the urethra is a partial or completely open “plate” dorsally on the penis or between the clitoral halves in the girl.
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Classic bladder exstrophy (CBE or BE)—the urinary bladder is an open plate on the lower abdomen, always associated with epispadias. The phallic length in males is foreshortened compared to the general population. In females, the vaginal opening is more vertically oriented, and the vagina may be shorter and wider than normal. Children with BE typically have an anteriorly located anus; however, CBE is rarely associated with other organ system malformation.
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Cloacal exstrophy (CE)—in which the bladder and the ileocecal junction of the bowel are an open plate on the lower abdomen and the hindgut is truncated and terminates in the perineum. This condition is also known as the omphalocele/exstrophy/imperforate anus/spinal defect (OEIS) complex.
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Exstrophy variants—in which partial manifestations of the above anomalies are seen; they commonly lack symmetry in the sagittal plane.
Children born with a diagnosis along the EEC spectrum undergo major reconstructive surgery early in life and will require lifelong care and follow-up to ensure kidney and bladder health, as well as to support the psychosocial, sexual, and fertility health as they age into and go through adulthood.
Bladder Exstrophy
Classic BE occurs in approximately one per 50,000 live births, with about equal incidence in males and females. CE is rarer with an incidence of 1 in 300,000. Since the 19th century, various efforts to manage BE have been described. Because the condition is rare, these approaches were empiric and usually unsuccessful. Until the 20th century, there was no effective surgical technique. Even now, optimal management is elusive and surgical reconstruction may require multiple procedures.
Diagnosis
BE can be diagnosed antenatally, although many affected fetuses are not identified until birth. Ultrasound (US) can usually detect BE before the 20th week of gestation by noting absence of the urinary bladder as a fluid-filled structure within the fetal pelvis. Other US findings include :
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A semisolid mass protruding from the abdominal wall
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A lower abdominal protrusion
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An anteriorly displaced scrotum with a small phallus in male fetuses
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Normal kidneys in association with a low-set umbilical cord
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An abnormal iliac crest widening
Findings such as low umbilical cord insertion and the location of the genitalia will only be seen if the fetus is examined in a sagittal plane. The iliac angle will be about 110° rather than the usual 90°. Since the kidneys and urine production are typically normal in these fetuses, amniotic fluid levels are usually normal. , Any abnormalities seen on US should prompt a fetal MRI, which provides better visualization and the ability to characterize the exstrophy or variant and distinguish exstrophy from other abdominal-wall defects.
Prenatal diagnosis helps provide for prenatal counseling, optimal perinatal management, and the chance to be delivered near a pediatric center where skilled newborn care is available to treat these babies. This counseling should include the expertise of a fellowship-trained pediatric urologist experienced in the care of children with exstrophy.
Pathogenesis
Experts disagree on the embryologic explanation for the development of BE. In the prescientific era, the cause of BE was attributed to trauma to the unborn child causing ulceration of the abdominal wall and subsequent bladder herniation. Today, we know that the developing human embryo does not normally pass through a stage that corresponds to exstrophy. This knowledge excludes arrested development and implicates an error in embryogenesis involving the cloacal membrane. The mesodermal membrane folds to form and separate the coelomic cavity from the amniotic space late in the 3rd week of development. The intermediate layer of this mesoderm forms the urogenital system. Disruption in this part of the membrane is thought to lead to EEC. Normally by the 5th week, the mesoderm has formed lateral folds that tubularize into the gut tube and cloaca. However, if the mesenchymal cells do not migrate appropriately during the 4th week of development, the EEC ensues. The actual reason the intermediate mesoderm does not migrate appropriately into place to separate the cavities and form the abdominal wall is not known. Several hypotheses have been tested, including physical obstruction of the mesodermal migration, premature rupture of the cloacal membrane, and cellular dysfunction that limits migration of the mesoderm.
To explore the theory that early disruption of the cloacal membrane results in diagnoses within the EEC, a model of CE in the developing chick embryo was created by using a CO 2 laser to create an early dehiscence in the tail bud caudal to the omphalomesenteric vessels. This model suggested that exstrophy may result from failure of the mesodermal ingrowth between the ectoderm and endoderm of the cloacal membrane, which then later ruptures prematurely. It is hypothesized that such an event could be caused by early hypoxemic infarction in the region of the tail bud with subsequent cellular loss of the mesoderm followed by herniation of the developing bladder or cloaca. This type of ischemic injury has also been implicated as the cause of gastroschisis and could explain the spectrum of the exstrophy-epispadias complex.
Another possible mechanism resulting in a similar pathophysiology could be a defect in a genetic switch, which results in premature senescence of the infraumbilical membrane (analogous to an ischemic injury). This mechanism would imply an epigenetic basis for exstrophy.
Animal models to study BE have been difficult to create. In an exstrophy sheep model, a significant increase in the ratio of collagen-to-smooth muscle was noted in exstrophic versus normal control bladders ( P < .05). These histological changes of the ratio of collagen to smooth muscle content are similar to changes seen in human BE specimens.
Recently a genetic murine model of Bladder Exstrophy and Epispadias Complex (BEEC) was created using a p63 −/− knockout that phenotypically demonstrated the complete spectrum of BEEC, including exstrophy, epispadias, separation of pubic bones, as well as imperforate anus and exomphalos. This model, combined with previously demonstrated mesenchymal-epithelial signaling, is leading to further hypotheses of the pathways involved in the development of BEEC.
While historically BE had been thought to be potentially due to environmental exposure or even an infectious pathogen, to date, the exact underlying cause of exstrophy remains in question. There is clearly a genetic component. Siblings of children with BE have an incidence of BE that ranges from 0.3% to 2.3%, much higher than normal. The incidence in children in whom one parent had exstrophy has been reported to be 1.4%, or 400-fold higher than the general population. However, the numbers that these statistics are based on are small. To date, 37 familial cases of BE have been reported, the most recent of which describes a mother and son with BE. ,
Prenatal counselors estimate the risk of recurrence in a sibling of a patient with exstrophy at about 1% with a 1 in 70 chance of transmission to the progeny of an affected parent. A Florida population-based study found multiple births had a 46% increased risk of birth defects, with BE being the 5th highest adjusted relative risk. These findings support a multifactorial etiology with evidence for genetic predisposition. More recently, an epidemiologic survey of families with BE found no link between exstrophy and parental age, maternal reproductive history, or periconceptional maternal exposure to alcohol, drugs, chemical noxae, radiation, or infections. Periconceptional maternal exposure to smoking was noted to be significantly more common in patients with CE. Specific genes and copy number variants are potentially associated with BE. A recent genome-wide association study has implicated a gene (ISL-1) on chromosome 5q11.1, which may be a susceptibility gene for BE. However, in other studies evaluation of copy number variants (CNVs) showed that single genomic CNV are unlikely to be the cause of BE, though this cannot be ruled out. Whole-exome sequencing and genome-wide association studies are in progress to begin to identify candidate genes that may contribute to the likely multifactorial etiology of BE.
Principles of Reconstruction
The initial goals of bladder exstrophy repair are to close the bladder and urethra and to reconstruct the genitalia to create functional organs for continence, voiding, and sexual function. By achieving a successful primary repair, the bladder can cycle and grow in capacity, and can provide safe storage under low pressure. The goal of closure is also to create a competent bladder neck that can coapt to provide continence and also can relax to allow a sustained detrusor contraction to result in normal voiding with complete emptying. Achieving normal bladder storage and emptying minimizes the risk of upper urinary tract deterioration, prevents urinary tract infections (UTIs) and vesicoureteral reflux (VUR), and decreases the risk of urinary calculi.
Natural History and Early Attempts at Treatment
Children with BE can survive untreated; however, significant morbidity can include skin breakdown secondary to total urinary incontinence, tumor development within the chronically exposed bladder plate, and significant psychosocial morbidity. In contrast, when these patients receive effective surgical and medical treatment, they can lead productive, healthy lives with minimal and manageable morbidity.
Very early efforts of exstrophy management were directed at partial reconstruction of the abdominal wall to allow the application of a urinary receptacle to collect urine. Early attempts at closing the bladder were fraught with complications, which led to surgical urinary diversion through the creation of ureterosigmoidostomies (USOs) with equally poor results. It was only with progressive understanding of urinary tract and bladder physiology, the effect of surgery on urine storage and emptying, and the concept of clean intermittent catheterization (CIC) that the care of these children has evolved to its current manageable, yet imperfect state.
Operative Approaches
A wide range of operations have been developed to repair BE. These can be grouped as (1) urinary diversion or (2) anatomic reconstruction. Anatomic reconstructions include single and multistaged repairs, with progressive degrees of delayed reconstruction. Surgeon preference and experience, patient anatomy, previous operations, availability of tertiary care facilities, and access to medical care and resources all play a role in choosing a specific operative procedure for a particular patient.
Urinary Diversion
Primary urinary diversion is not commonly performed in the United States or in most of Europe. Urinary diversion has largely been abandoned in favor of primary bladder closure. However, continent urinary diversion techniques produce a more consistent degree of dryness with fewer required surgeries and fewer early complications than that achieved with anatomic reconstruction. , Techniques for constructing urinary diversions are listed in Table 56.1 .
Table 56.1
Surgical Options for Urinary Diversion
| External Diversion (Continent Urinary Reservoir) | Internal Diversion (Rectal Sphincter–Based Continence) | Incontinent Diversions |
|---|---|---|
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Continent diversions can be completely internalized and rely on the rectal sphincter complex, or can be partially externalized, requiring catheterization of a continent stoma. Incontinent diversion can also be employed. This avoids the complications associated with continent reconstruction such as a failed continence mechanism resulting in persistent incontinence, urinary retention, and dependence on CIC to empty the bladder and stomal complications.
Diversion can be combined with cosmetic and functional reconstructive procedures for the external genitalia. Because of the difficulties encountered with functional bladder reconstruction, especially in resource poor settings such as developing countries, early urinary diversion advocates argue that diversion achieves the primary goals of dryness with fewer operations and higher success rates than are achieved with bladder closure and urethral reconstruction.
One of the earliest forms of diversion used in BE reconstruction was the ureterosigmoidostomy (USO). This diversion allowed the high pressure of the contractile sigmoid to reflux infected urine or feces resulting in severe infections, and long-term complications include hyperchloremic metabolic acidosis, chronic pyelonephritis, bladder calculi, and a 250- to 300-fold increased risk of adenocarcinoma developing at the anastomosis of ureter(s) and colon. As a result of these complications, USO was replaced by incontinent urinary diversions such as colonic and ileal conduits. A significant disadvantage to these conduits is the associated incontinent abdominal stoma and the need for a receptacle/appliance, as well as a high rate of bowel segment stenosis and obstruction and infection.
The Mainz II pouch (a detubularized sigmoid pouch) provided a significant improvement to the USO. , This detubularized pouch reduced bladder and ureteral pressures and improved nighttime continence. In one study, renal preservation rates in children treated primarily with a urinary rectal reservoir (Mainz II pouch) approach 92%, with continence rates up to 97%.
The Heitz–Boyer–Hovelaque procedure involves isolation of a rectal segment for ureteral implantation followed by posterior sagittal pullthrough of the sigmoid colon through the anal sphincter. A small series using this approach reported continence rates of 95% with an acceptable complication rate. A modern long-term evaluation of patients treated with anal urinary diversion distinguished between a 97% daytime urinary continence rate and a 65% nighttime continence rate with loss of small amounts of urine during sleep or with sexual activity. An alternative rectosigmoid bladder reservoir was evaluated for continence results in the modern era, performed both for primary treatment and salvage repairs. Complete rectal continence was only 52% in this cohort, while the remainder had leakage during passage of flatus or abdominal straining.
Frequent bladder emptying may reduce the risk of metabolic electrolyte imbalances since frequent emptying of the rectal reservoir reduces the contact time between urine and the absorptive rectal mucosa. The standard treatment of metabolic acidosis is with oral bicarbonate replacement. While reconfiguration of the pouch and frequent emptying may reduce risk of infection and wetting, the risk of malignancy remains a concern. Various modifications of the rectal reservoir to prevent admixture of feces and urine may decrease the incidence of adenocarcinoma. A study which shared a 45-year experience found 8 of 82 patients developed neoplasms, most often at the ureterointestinal anastomosis. Four of these patients died shortly after diagnosis, while the remainder were managed with resection and revision of the diversion method.
Anatomic Reconstruction
The first efforts at anatomic reconstruction for BE were unsuccessful but set the stage for the current anatomic approach. In 1881, Trendelenberg described an exstrophy closure emphasizing the importance of pubic reapproximation in front of the reconstructed bladder in order to achieve continence and prevent dehiscence. However, because of discouraging results, anatomic reconstruction was largely replaced by urinary diversion in the early part of the 20th century. In the latter half of the 20th century there were several series of patients who underwent single-stage reconstruction, with most reporting continence rates of 10%–30%. The most concerning complication was the high incidence of renal damage, reported as up to 90% in some series, generally secondary to bladder outlet obstruction.
As a result of devastating upper tract damage and the low rate of urinary continence with single-stage approaches, reconstructive efforts were modified toward staged bladder reconstruction. This approach was pioneered in the 1970s and further refined to what is now known as the modern staged repair of exstrophy (MSRE). , Later advances in single-stage reconstruction, combined with the advent of clean intermittent catheterization, led to a resurgence of this approach and the development of the complete primary repair for exstrophy (CPRE), which has now developed alongside the MRSE.
The primary goal of both approaches is to reconstruct the abdomen and genitalia to achieve anatomic and functional normalcy with minimal operative morbidity. In the next section, the two currently popular surgical techniques, the CPRE, the MSRE, are described in addition to the Kelly radical soft tissue mobilization, which is increasing in popularity as an emerging surgical technique for EEC.
Preoperative Care
After delivery, to reduce trauma to the bladder plate, the umbilical cord should be ligated with silk suture rather than a plastic or metal clamp. A hydrated gel dressing or plastic wrap can be used to protect the exposed bladder from superficial trauma from a diaper. The baby should undergo an US to evaluate the kidneys and to establish a baseline examination for later US studies, as well as an anterior-posterior X-ray of the pelvis to assess the degree of pubic diastasis. Preoperative spinal US examination should be considered if sacral dimpling or other signs of rare spina bifida occulta are noted on physical examination. Although associated spinal abnormality is common with CE, it is rare with BE.
If closure is performed beyond the first 72 hours of birth, the baby may be discharged from the hospital with the mother, thus providing time and proximity for bonding with the parents. Preoperative antibiotic prophylaxis is not required. However, perioperative and postoperative antibiotics are used to decrease the risk for infection following reconstruction.
Operative Considerations
Traditionally, primary BE closure was performed in the immediate newborn period, prior to 72 hours of life. This potentially allowed for anatomic closure without the use of osteotomies and decreased bladder exposure. Some authors posited the importance of immediate postnatal exstrophy closure, reporting that infants closed before 7 days of age required fewer bladder augmentations, while continence rates were the same in the early or delayed closure. Closure of infants less than 72 hours old with diastasis less than 4 cm without osteotomy had the same failure rates as those performed with osteotomy in another study. In the past, proponents of early closure pointed to decreasing bladder exposure, which can lead to histological changes such as acute and chronic inflammation, squamous metaplasia, cystitis glandularis and cystitis cystica, and muscular fibrosis, all of which may adversely impact bladder capacity and compliance. More recently, primary polyps were not found to change outcomes in bladders closed either early or delayed. Other early studies of the anatomy and physiology of the newborn exstrophy bladder showing an “immature” physiology with fewer and smaller nerve fibers and less smooth muscle supported the hypothesis that early closure could help to “mature” the bladder by early restoration with bladder cycling. ,
Delayed Primary Closure
Several recent studies have advocated for delayed primary closure, especially in regard to the CPRE approach, either in primary or failed exstrophy closures. Proponents of delayed repair argue that it is safer for the child, provides a more coordinated surgical effort, and allows an elective operation so that the most expert team of clinicians and personnel are available. Delay in closure can allow time for the baby to become more robust and stable, and allows for parental bonding before the child is placed in traction for 4–6 weeks. Moreover, in an era of the development of high-volume centers, delayed closure allows for consultation and transfer if needed. A report showed no difference in ultimate bladder capacity between newborn closure and closure delayed for 1–9 months. Others have similarly shown it is possible to wait months after birth with good results. The delay may be used to stimulate the penis with testosterone with the goal of reducing the chance for glans injury, and there have been good short-term outcomes reported with this approach in small series. The successful use of a delayed closure approach is predicated on adequate protection of the exposed tissue. However, there can be an increased cost (as much as 50%) with delayed closure. Long-term outcomes will take years to mature.
Considerations during general anesthesia include minimizing abdominal distention, which can increase intraabdominal pressures postoperatively and can lead to a compartment syndrome, which may compromise renal function and increase the risk of wound dehiscence. Awareness of the potential for compartment syndrome is particularly important during the initial repair of a baby with CE, with requisite omphalocele repair. Nitrous oxide should be avoided as it can cause bowel distension. An epidural catheter can decrease the need for narcotics and inhaled anesthetics during the operation and keeps the baby comfortable postoperatively. Tunneling the epidural may reduce the risk of infection if it is to be used for prolonged periods after repair. Postoperatively, maximal urinary drainage with ureteral stents and suprapubic tube are critical to divert urine away from the bladder as it heals. (See Table 56.2 .)
Table 56.2
Perioperative Adjuncts to Successful Bladder Exstrophy Closure
| Intraoperative | Postoperative |
|---|---|
| Avoid abdominal distention– NG tube for continuous decompression, avoid nitrous | Tunneled epidural for pain management |
| Epidural to avoid narcotics | Maximal urinary drainage |
| Careful fluid management | Immobilization with traction or spica cast |
| Antibiotics |
Adjunctive Aspects of Repair
Indirect inguinal hernias are commonly associated with BE in both boys and girls. , They arise as a consequence of enlarged internal and external inguinal rings combined with compromised fascial support and lack of obliquity of the inguinal canal. To assess benefits of preemptive hernia surgery, a single institution reviewed its experience with 43 patients with BE. Of the 25 that did not undergo inguinal hernia repair at the time of original closure, 9 went on to require hernia surgery, while no children who had a hernia repair at the time of surgery suffered any complications from the repair. Thus, they have advocated for inguinal exploration and repair of inguinal hernia at the time of exstrophy closure. Alternatively, in a series of 136 patients with a history of BE, closure with osteotomies decreased the recurrence of inguinal hernias and the development of primary hernias.
Due to the high incidence of VUR after exstrophy closure (up to 75%) in patients with closed bladder exstrophy, there have been some surgeons who perform ureteral reimplantation at the time of initial closure. The cephalotrigonal reimplantation has been described in patients with bladder exstrophy. This approach reimplants the ureter in a safe way, accounting for the native inferior insertion at an almost right angle into the bladder, providing a more gradual course through to the neohiatus and greater distance from the bladder neck to the ureteral orifices. The safety and efficacy of ureteroneocystostomy at the time of initial closure has been shown.
Osteotomies
T echniques
Infants with bladder exstrophy have a wide and flattened pelvis that is laterally displaced, leaving little support for genitourinary organs. There is external rotation of the posterior pelvis, shortening and external rotation of the pubic rami, and a wide pubic diastasis. , Approximation of the externally rotated bony pelvis is critical to decrease tension on the abdominal-wall closure, to help reapproximate pelvic floor musculature and place the bladder and urethra deep within the pelvic diaphragm. Effective reapproximation of the pubic symphysis decreases the rate of abdominal-wall dehiscence and improves rates of continence in children closed outside of the immediate newborn period. Osteotomies are performed to aid in the closure of the pelvis.
Osteotomies offer several advantages when performing the anatomic approach to BE closure including: (1) aiding in pubic symphysis apposition, diminishing tension on the fascial repair; (2) optimizing anatomic placement of the bladder, bladder neck, and urethra in the pelvis; (3) improving the reapproximation of the corporal and clitoral bodies; and (4) decreasing the chance for later uterine prolapse. Traditionally osteotomies have been done for any child over 72 hours old, in newborns with an exceptionally wide diastasis, and in reoperative BE closure/repair. However, there is some data supporting the value of osteotomies even within the first 72 hours. Osteotomies are usually performed at the same setting as bladder repair to help secure the closure, except in cases of extremely wide diastasis in cloacal exstrophy, when the osteotomy may be performed in a staged fashion.
Bilateral iliac osteotomy can be performed through an anterior or posterior approach. Posterior iliac osteotomies are performed prone, after which the patient is then repositioned for the bladder closure. Anterior iliac osteotomies are performed with the patient supine. This avoids repositioning between the osteotomy and the bladder closure. Anterior osteotomy may be done through an anterior diagonal technique or a combination of bilateral and anterior innominate and vertical iliac osteotomies, which have had excellent initial and long-term results compared to anterior iliac osteotomies alone in some series. , There are other less commonly performed approaches including diagonal midiliac osteotomy, division of the superior pubic ramus, and other innovative approaches, but these are not widely used.
Immobilization
After the primary reconstructive procedure for exstrophy, either with or without osteotomy, the patient must be immobilized to decrease stresses on the closure. There are various types of immobilizations used, with no clear optimal method. Options include: (1) modified Bryant’s traction; (2) external fixation; or (3) spica cast. Each of these has its benefits and drawbacks. Modified Bryant’s traction immobilizes the baby within a bed and the hospital for 4–6 weeks, and the binding on the legs can cause skin injuries to the legs and feet. External fixation also immobilizes the patient, but carries a risk of external wound infections along the pin sites and therefore the pin sites require daily cleaning In some centers, external pinned fixation is recommended for older children in whom the bones are mature enough to hold a pin. The spica cast allows for more mobility and earlier discharge from the hospital , and is associated with decreased length of stay and lower cost. Another option for a spica cast is creation of a “window” over the epidural catheter entry site. This facilitates inspection of the site and management of the catheter. We use a hinged spica cast that is easier to remove (only the outer wrap can be cut and then replaced, or the two halves are kept together by Velcro wraps so the skin can be checked daily; Fig. 56.1 ). Modified Buck’s traction has also been used by many groups with success. A posterior lightweight splint can be used in newborns when the child is out of traction to maintain hip adduction. Internal fixation may be necessary in older patients. Femoral nerve palsy is a possible complication with fixation that must be monitored, and the incidence can be reduced by gradually tightening the fixator. Osteotomies are not a component of the classical Kelly technique.
The patient is immobilized after surgery to prevent external hip rotation, to decrease lateral stresses on the closure, and to optimize pubic apposition in the early postoperative period. A number of immobilization techniques are possible. This photograph shows a hinged spica cast from an anterior view (A) with a large section open to be able to see the abdomen, and a posterior view (B) to provide access to the tunneled epidural site and enable diaper changes. In (C), note the suprapubic bladder catheter ( long arrow ) and two ureteral stents ( short arrow ) that act as a urethral catheter.
Complete Primary Repair for Exstrophy
General Principles
Complete primary repair of bladder exstrophy (CPRE) was initially introduced by Grady and Mitchell in 1999. This technique includes the combination of bladder closure, anatomic bladder neck narrowing, urethral elongation, epispadias repair, and umbilicoplasty in a single operation early in infancy (6–12 weeks) but not during the newborn period. The key motivation behind this technique is the early introduction of bladder outlet resistance, thus creating an environment that facilitates bladder growth and development. Bilateral ureteral reimplantation may be performed at time of CPRE to prevent vesicoureteral reflux. Decision for ureteral reimplantation centers around the size and quality of detrusor tissue. At times, bilateral ureteral reimplantations are necessary to perform bladder neck reconstruction, due to the proximity between the bladder neck and ureteral orifices. Pelvic osteotomies are always performed to reduce tension on the anterior abdominal wall and surgical reconstruction.
CPRE Technique in the Boy with Bladder Exstrophy
Preparation and Assessment of the Anatomy
Total body preparation is performed. The anatomy should be surveyed at the outset of the procedure ( Figs. 56.2 and 56.3 ). Tegaderm is placed over the anus. A stay suture is placed transversely in each hemiglans of the penis. Important landmarks, including the most medial aspect of each pubic symphysis, bladder neck (longitudinal fibers between the verumontanum and ureteral orifices), verumontanum, and ureteral orifices facilitate orientation and help plan dissection. The neoumbilicus is marked at level 1–2 fingerbreadths above the most cephalad level of the anterior superior iliac spine. Each ureteral orifice is intubated with a small caliber feeding tube and secured with absorbable suture ( Fig. 56.4 ). Large bladder polyps are excised to eliminate irregularity, as this often facilitates bladder closure. Following polyp excision, the bladder mucosa is approximated with running absorbable simple suture. Incision lines are marked at the perimeter of the bladder, bladder neck, and urethral plate. The umbilical stump or scar is incorporated with the bladder via an inverted “V” incision marked at the cephalad extent of the skin incision caudal to the neoumbilicus. This tissue will eventually be discarded, but functions as a “handle” during dissection, initial incision, and delineation of planes.
Preoperative bladder exstrophy anatomy in the boy. Penis end-on view in the natural state. Note the typical space between the ventral aspect of the penis and the cephalad extent of the scrotum.
The penis is reflected ventrally toexpose important anatomy and landmarks of the urethral plate, verumontanum, and ureteral orifices.
Incisions have been marked for the apex of the dissection, perimeter along the bladder, and the longitudinal lines of incision along the urethral plate.
The incision begins at the cephalad extent (inverted “V” in Fig. 56.4 ) and is carried along the perimeter of the bladder and urethral plate as marked, using fine-needle point electrocautery. The incision is deepened at its cephalad extent and obliterated umbilical vessels are identified, isolated, and ligated. The peritoneum is carefully separated with sharp and blunt dissection from the external surface of the bladder dome and posterior and lateral walls. A traction suture is placed in the umbilical stump/scar to facilitate dissection. In order to identify the often-difficult plane between the bladder wall and the rectus muscle and fascia, first the fatty plane between the skin and the anterior surface of the anterior abdominal wall (rectus) fascia is identified. Dissection is carried along the anterior surface of the fascia, exploiting the “fat is your friend” concept in developing this important plane. In the thin patient with a paucity of abdominal-wall fat, beginning this dissection at the level of the pubic bones, where a fat layer typically exists, and progressing in a cephalad direction, may facilitate this step. Accurately identifying this initial plane and the medial edge of the anterior abdominal-wall (rectus) fascia facilitates accurate identification and dissection of the plane between the medial and posterior aspect of the abdominal-wall/rectus fascia and the bladder edge. Adherent rectus and detrusor muscle fibers may be distinguished by the longitudinal course of the rectus component. Continued dissection along the perimeter of the bladder is facilitated by insertion of the (right-handed) surgeon’s left index finger inside the bladder, inverting the bladder. This allows better appreciation of the correct plane. The primary surgeon performing this dissection, if right-handed, is positioned to the left of the patient.
Intersymphyseal Bands
Dissection, as described above, coursing caudally along the lateral aspects of the bladder wall will eventually lead to the intersymphyseal band attachments that tether and displace the bladder trigone and bladder neck anteriorly. As the dissection progresses and tissue permits, blunt dissection along the lateral bladder wall will exploit the plane by identifying and entering the perivesical fat plane. This facilitates “pushing” of the distal aspect of the bladder medially and creates space underneath the intersymphyseal band on either side of the bladder neck. Using the medial edge of the pubic bone as a reference, the intersymphyseal bands are now divided. This is perhaps the most important part of the dissection to allow appropriate placement of the bladder, bladder neck, and posterior urethra deep in the pelvis. This can be continued in a caudal to cephalad direction following urethral plate dissection.
Urethral Plate Dissection
This step is optimized via an initial ventral approach. Preputial skin adhesions to the glans are released, and the skin incision is marked ventrally parallel to the corona. The penile shaft is degloved of its skin. At the lateral aspects of this dissection, care is taken to avoid injury to the corpora and neurovascular bundle, as these structures are often adherent to the thin skin in this area. The ventral approach continues along the medial aspect of the corpora cavernosa using sharp dissection and bipolar electrocautery to develop this plane, allowing both hemostasis and preservation of the blood supply to the urethra ( Fig. 56.5 ). Visualization and dissection of this plane is facilitated by the right-handed surgeon (on the patient’s right) applying gentle “lifting” pressure with the surgeon’s left index finger underneath the dorsally reflected penis. This technique both turns the corpora cavernosa laterally and elevates the corpus spongiosum/ventral urethral plate. This dissection proceeds proximally to the penoscrotal junction where the corpora separate. Dorsal urethral dissection begins with scissors, at the lateral edge near the longitudinal midpoint of the urethral plate ( Figs. 56.6 and 56.7 ). The sharp dissection is medial and parallel to the neurovascular bundle. Dissection is carried medially alternating from dorsal to ventral until the corpora begin to free from the urethral plate, usually at the midpoint of the dissection. At this point, the surgeon passes a vessel loop between the corporal body and the urethral plate. The urethral plate dissection continues proximally toward the bladder neck and distally toward the glans. The vessel loop gently reflects the urethral plate away from the midline. In a modification of the complete penile disassembly technique, the glans is kept in continuity, which seems to reduce the risk of venous stasis and glanular ischemia in the first few postoperative hours. In the absence of dorsal “bowing” secondary to a short urethral plate, the urethra was kept in continuity with the glans to preserve urethral plate vascular communication and symmetry. A urethral width of approximately 15 mm is maintained throughout the entire length of the urethra all the way to the bladder neck. This maintains symmetry and blood supply, while still permitting anatomically correct posterior/ventral placement of the distal urethra and urethral meatus. If the urethral plate is short and the “bowing” effect is enough to compromise penile length, the distal urethra can be detached from the glans as long as the left and right hemiglans remains intact.
Initial ventral approach to urethral plate dissection with microforceps bipolar electrocautery to dissect corpora cavernosa off corpus spongiosum.
Diagram of dorsal dissection of urethral plate, separating the urethral plate off the corpora cavernosa.
Intraoperative photograph of dorsal dissection of urethral plate. Corpora cavernosa encircled with yellow vessel loop bilaterally. Urethral plate elevated with red vessel loop. Anatomical dissection is complete and fully prepared for approximation of the tissues and completion of the repair.
Deep Dissection
The dissection proceeds proximally, medial to the neurovascular bundle to the level of the prostatic urethra and bladder neck. This allows for maximal extension of the corpora and permits the bladder neck to be rolled in the midline with little or no tension. Eventual approximation of these structures will also be facilitated by iliac osteotomies and subsequent bony pelvic closure and therefore dissection on either side of the bladder neck should be limited to what is necessary to provide a tension-free anastomosis. Hemostasis should be carefully obtained with bipolar electrocautery where needed to prevent current from traveling along the corpora, neurovascular bundle, or both.
Elongation of the Urethra/Bladder Neck Development
To provide near-normal postoperative urethral anatomy, the width of the urethral plate is maintained cranially before widening at or just proximal to the bladder neck. The level of the bladder neck is identified between the verumontanum and the ureteral orifices by the appearance of ridges or folds in the urothelium that run in a longitudinal orientation. We mark the proposed incision sites for the bladder neck reconstruction with pinpoint cautery. The bladder neck width is typically marked out to be 2–3 mm wider than the urethral plate width, which is approximately 14–15 mm. The excess width at the bladder neck is deepithelialized and the excess detrusor is either resected or incorporated into the closure ( Figs. 56.8 and 56.9 ).
Intraoperative incisions marked for elongation of the urethral plat proximal (cephalad) to the level of the bladder neck (dotted purple line) .
(A) Previous dissection beginning at the verumontanum (dotted green line) with increasing width taper to the bladder neck/bladder (dashed green arrows) . (B) Current dissection with the urethra extended proximally (dashed purple lines with arrowheads) to form a more acute angle at the bladder neck (dotted purple line) .
Approximation of Tissues (Tubularization of Neourethra, Bladder Neck Approximation, Bladder Closure)
U rethra
The urethral meatus may be advanced as needed with midline longitudinal incision of the glans followed by transverse approximation (Heineke–Mikulicz procedure) using fine absorbable interrupted sutures (also known as the incorporated glanuloplasty and advancement meatal [IPGAM] technique). The tubularization of the urethral plate begins at the meatus over either the ureteral catheters or urethral stent using imbricating interrupted sutures. Minimal mucosa is incorporated to invert the mucosa and decrease the risk of fistula (needle trajectory incorporating serosa/inverting mucosa). Interrupted sutures are placed and then tied later to provide clear and exact visualization of the urethral plate edge, with 6–0 polydioxanone (PDS) or polyglyconate (Maxon) for the distal urethra, 5-0 PDS or Maxon for the midproximal urethra, and 4-0 PDS or Maxon for the proximal urethra-bladder neck. After placing the first sutures distally to begin the urethroplasty, several sutures are placed at the level of the bladder neck. This serves several purposes, as it takes some tension off the urethral approximating sutures, provides clear delineation of this important anatomical landmark, and aids technically symmetrical urethroplasty ( Fig. 56.10 ).
Completed CPRE in the boy.
B ladder N eck and B ladder
The bladder neck and bladder are approximated with continuation of simple interrupted 4-0 PDS sutures. Placement of one suture at the bladder dome apex facilitates closure. The umbilical stump or scar should be excised, along with any grossly epithelialized bladder mucosa, prior to approximation at the bladder dome. A suprapubic cystostomy tube is passed through the neoumbilical site and into the bladder at a separate site lateral and/or cephalad to the apex of the bladder closure.
P ubic B one A pproximation
The subcutaneous tissue is elevated from the anterior surface of the pubic bones bilaterally to clearly identify these structures and facilitate accurate suture placement. The pubic bone is approximated using horizontal mattress and simple interrupted either #1 or 0 PDS placed through the bone. Manual approximation of the pubic bones is maintained while tying these sutures. Of note, it is important that the interrupted sutures, especially the simple one, is not placed too deep within the pelvis, as this can interfere with, or place tension on, the bladder neck and urethral tubularization.
Corpora Cavernosa A pproximation and Glansplasty
The corpora cavernosa and glans are examined carefully for any evidence of impaired blood flow or frank ischemia. Trimming of the lateral edges of each hemiglans with verification of expected bleeding (viability) is a necessary step for plastic approximation of the glans (glansplasty) over the distal urethra and may aid substantially in assessing blood flow. Alternatively, a 30-gauge needle can be used to puncture the glans to assess for blood flow. If blood flow is compromised, the sutures approximating the pubis are immediately released and replaced with less tension to prevent glans ischemia. At times, glans ischemia may not be immediately apparent. Hence, it is essential that blood flow to the glans is rechecked prior to closure. As long as blood flow continues the penile reconstruction resumes with closure of the urethra and glans. Subcutaneous simple interrupted sutures approximate the glans in the midline. Pending the need to address dorsal penile curvature, several interrupted or horizontal mattress sutures of 4-0 PDS material are placed on the dorsal aspect, approximating the corpora cavernosa. External rotation of the corpora proximally, with gentle internal rotation distally at the level of the glans, may help correct for dorsal curvature and improve corporal length.
Abdominal Wall Closure
Rectus muscle and fascia are approximated in two layers with running simple 2-0 PDS. The typical transverse lower abdominal skin crease is an important landmark to guide symmetrical abdominal-wall subcutaneous tissue and deep dermal approximation. A subcuticular skin closure is then performed.
Penile Shaft Skin Coverage
Penile shaft skin coverage can be challenging, especially in patients with higher external corporal tissue. Several techniques have been described, including Byars skin flaps, buttonhole, or ventral rotational skin flap. A primary dorsal closure is typically not possible. Byars flaps can be used; however, this leaves a dorsal scar. The buttonhole technique does not result in a dorsal scar but results in excess tissue or “dog ears” on the 3 and 9 o’clock positions. The ventral rotational skin flap described by Pippi Salle can be used to rotate the ventral shaft skin 90 degrees on a pedicle and place the seam on the lateral aspect of the penis. In any type of skin coverage, tacking sutures should be placed to prevent penile shaft skin from riding over the corporal bodies and “burying” the penis.
Umbilicoplasty
There are several options for umbilicoplasty. In one, a same-site, full-thickness skin graft may be used for umbilicoplasty. A circle of skin is marked and excised and completely defatted. A “core” of subcutaneous tissue and fat deep to the circular graft is excised down to the level of fascia. The skin is then tacked back down to the fascia. Alternatively, a rhomboid flap can be elevated, curved around itself, and the medial (midline) margin sutured to the fascia to provide a deep umbilicus. Additionally, a Z-shaped or trapezoidal flap can be used to create a deep ring.
Drainage
The suprapubic cystostomy tube (typically 7 or 8.5 Fr) and ureteral stents are secured with nylon suture at the skin level. The suprapubic cystotomy tube may or may not exit at the site of umbilicoplasty, but it is imperative that this is extraperitoneal to prevent bowel obstruction. Ureteral stents may exit via the neourethral lumen if an ureteroneocystostomy is not performed. Alternatively, the ureteral stents may exit via the neoumbilical site or right or left lower quadrant. If ureteral stents are not brought out through the urethra, then a urethral stent should be placed in the neourethra.
Immobilization
A spica cast or bivalved spica cast can be used for postoperative immobilization to optimize pelvic stabilization and healing. Alternative traction techniques have been described for postoperative immobilization.
CPRE Technique in the Girl with Bladder Exstrophy
Preparation and Assessment of the Anatomy
Total body preparation is performed similar to that for CPRE in the boy. Tegaderm is placed over the anus and the anus can be packed to prevent leakage of stool during surgery ( Fig. 56.11 ). Each ureteral orifice should be intubated with a small caliber feeding tube and secured with absorbable suture. The bladder surface is examined for polyps with excision as needed. Pubic bones are marked bilaterally, and incision lines are marked at the perimeter of the bladder, bladder neck, and urethral plate. The future neoumbilicus site is marked in the patient’s midline at the level of the iliac crest. The umbilical stump or scar is incorporated with the bladder via an inverted “V” incision marked at the cephalad extent of the skin incision caudal to the neoumbilicus.
Preoperative bladder exstrophy anatomy in the girl with anatomic details. (A) View of the bladder plate from above, showing bladder polyps and ureteral orifices; (B) View of the perineum from below showing hemiclitori, labia minora, vagina, and anus.
Initial Incision and Delineation of Planes
Incision begins at the cephalad extent of the bladder and is carried along the perimeter of the bladder, using fine-needle point electrocautery, in a similar fashion to that for the boy with bladder exstrophy. In the girl, the caudal extent of the dissection is delineated with initial marking and superficial incisions along the lateral aspect of the urethral plate, just medial to the corpora cavernosa and clitoral tissue ( Fig. 56.12 ). Dissection with great care is critical at this step to safely maximize urethral plate width at this level and the eventual urethral meatus caliber, without injuring the corpora cavernosa or clitoris, a delicate balance. At the caudal extent of the dissection in the girl, a “Y-V” incision is made to advance the posterior vaginal wall more posteriorly into the perineum. This incision incorporates a thin margin of skin to provide strength and approximation of the vagina in the perineum. Following initial demarcation and dissection caudally, dissection is continued and deepened along the perimeter of the bladder in a cephalad to caudad direction, eventually encountering the intersymphyseal bands.
Urethral plate outlined between the clitoral halves and anterior to vagina.
Intersymphyseal Bands
Dissection, as described in the boy, coursing caudally along the lateral aspects of the bladder wall will lead to the intersymphyseal band attachments that tether and displace the bladder trigone, bladder neck, and urethral plate anteriorly. Blunt dissection along the lateral bladder wall allows identification and entrance into the perivesical fat plane. This facilitates development of the potential space beneath the intersymphyseal band on either side of the bladder neck. Using the medial edge of the pubic bone as a reference and a probe/urethral sound within the vagina, the intersymphyseal bands are carefully identified and divided. A sound within the vagina helps delineate the plane between it and the pelvic diaphragm. Dissection is maintained along the medial aspect of the pubic bone to decrease the risk of injuring the neurovascular bundle on the corpus cavernosum of the clitoris. A metal sound placed within the vagina is helpful in identifying the course of the vagina to prevent injury.
U rethral P late D issection
The urethral plate is fused to the anterior vaginal wall and this connection should be maintained intact. Disruption of this plane can lead to urethral stenosis.
Approximation of Tissues (Tubularization of Neourethra, Bladder Neck Approximation, Bladder Closure)
“Y-V” Advancemen t
The vagina is advanced caudally toward the anus along the perineum as a Y-V advancement. As needed, the labia majora are advanced into the perineum alongside the vaginal orifice to provide an appropriate cosmetic appearance. The vaginal mucosa can then be approximated to the skin using interrupted absorbable sutures.
Preplacement of Perineal Sutures
The urethral meatus is marked along the length of the urethra to the bladder neck to ensure sufficient length and width. The urethroplasty is completed using interrupted stitches; 6-0, 5-0, and 4-0 PDS or Maxon as the sutures progress from the urethral meatus to the bladder neck. A deliberate, but gentler attempt than in boys is made to form a bladder to promote continence ( Fig. 56.13 ). Interrupted sutures are used to complete the urethroplasty. A “four-corner” suture is preplaced prior to approximation of the pubic bones for eventual maturing of the urethral meatus ( Fig. 56.13 ). These need to be preplaced, as visualization is limited once the pubic bones are approximated in the midline. The bladder closure is completed now using a single layer using interrupted 4-0 PDS. The medial aspect of each hemiclitoris is deepithelialized in preparation for approximation in the midline. Again, preplacement of perineal and urethral meatus sutures prior to approximating the pubis allows optimal exposure of the tissues for accurate and precise placement.
Surgical modifications in the girl; (left) bladder neck gradually tapered into elongated proximal urethra (dotted lines) , and (right) sutures preplaced in order (prior to approximating the pubis); four-corner urethral meatus, anterior perineal soft tissue and pubis, then tied in reverse order.
Pubic Bones are Marked
Perineal sutures are placed but not tied. Manually approximating the pubic bones allows for a check of the symmetry of perineal and genital tissue. The pubis is then approximated toward the midline by placing and tying the two sutures of zero or #1 PDS in the same way as in the boy. Preplaced perineal sutures placed under direct vision are tied after the pubic closure with confidence in the accuracy of placement and position.
Abdominal-Wall Closure, Umbilicoplasty, Drainage, and Immobilization
During the reconstruction, the umbilicoplasty is performed in a similar fashion as in boys. Similarly, after the pubic bones are closed, the abdominal closure and immobilization are carried out for the girl ( Fig. 56.14 ) in similar manner to that for CPRE in the boy.
