Skeletal Defects

Formerly, classic bladder exstrophy was thought only to show the characteristic widening of the pubic symphysis caused by malrotation of the innominate bones in relation to the sagittal plane of the body along both sacroiliac joints. In addition, there was an outward rotation or eversion of the pubic rami at their junction with the iliac bones. More recently, Sponseller and colleagues (1995), using computed tomography (CT) of the pelvis with three-dimensional (3D) reconstruction, have further characterized the bone defect associated with both classic bladder exstrophy and cloacal exstrophy. In reviewing a large group of patients with exstrophy of the bladder, using pelvic CT scans and age-matched controls, Sponseller and colleagues (1995) found that patients with classic bladder exstrophy have a mean external rotation of the posterior aspect of the pelvis of 12 degrees on each side, retroversion of the acetabulum, and a mean 18 degrees of external rotation of the anterior pelvis, along with 30% shortening of the pubic rami, in addition to the previously described diastasis of the symphysis pubis (Fig. 124–3). In long-term follow-up there was a foot progression angle of 20 to 30 degrees of external rotation beyond the normal limits seen in early childhood, but this rotation improved with age. Likewise, patients with cloacal exstrophy not only had pelvic deformities to a greater degree but also had asymmetry of the preceding parameters between the right and left sides of the pelvis, malformation of the sacroiliac joints, and occasional dislocations of the hip (Sponseller et al, 1995).

Figure 124–3 Pelvic bone abnormalities noted in classic bladder exstrophy. The posterior bone segment is externally rotated (12 degrees mean on each side), but the length is unchanged. The anterior segment is externally rotated (18 degrees mean on each side) and shortened by 30%. The distance between the triradiate cartilage is increased by 31%.

Data from Stec and colleagues (2001a) using 3D models from CT scans have provided further insight into the bone defect of children born with classic bladder exstrophy. Using age-matched controls, they found that the sacroiliac joint angle (before closure) was 10 degrees larger in the exstrophy pelvis, being 10 degrees more toward the coronal plane than the sagittal (Fig. 124–4). Also, the bony pelvis in exstrophy has 14.7 degrees more inferior rotation than in healthy patients. Lastly, the sacrum in exstrophy patients has a 42.6% larger volume and 23.5% more surface area than in controls. These new findings will help with planning better osteotomies and better reduction of both the pubic diastasis and pubic long-term undergrowth in these patients.

Figure 124–4 A to C, Sacroiliac joint angles before closure in children with classic exstrophy 10 degrees larger than normal controls. The bony pelvic has 14.7 degrees inferior rotation compared with normal controls.

(From Stec AA, Pannu HK, Tadros YE, et al. Evaluation of the bony pelvis in classic bladder exstrophy using 3D CT—further insights. Urology 2001;58:1030.)

These rotational deformities of the pelvic skeletal structures contribute to the short, pendular penis seen in bladder exstrophy. Outward rotation and lateral displacement of the innominate bones also account for the increased distance among the hips, waddling gait, and outward rotation of the lower limbs in these children, which in itself causes little disability and usually corrects to some degree over time. Data from Sponseller and colleagues (2001) show an increased incidence of premature osteoarthritis of the hip in adult patients who were closed without an osteotomy. Although these findings do not affect function, periodic radiologic evaluation of the pelvis and lumbosacrum should be performed in adult life. The 30% shortage of bone in exstrophy pelvis has largely gone unexplained. Data by Stec and colleagues (2003) using sections from the bony pelvis in fetal exstrophy and normal aborted fetuses found that the ultrastructure, bone development, microscopic growth patterns, and endochondrial ossification were absolutely the same. Thus restoration of the physiologic shape of the pelvis would likely lead to more normal gross bone growth, decreases in shortage of bone, and a more appropriate distribution of the mechanical and development forces on a more closed normally functioning pelvic ring.

Spinal abnormalities have frequently been noted in children with cloacal exstrophy, but incidence in bladder exstrophy has not been studied. A study of 299 children with bladder exstrophy indicated spinal variations without clinical significance (spina bifida occulta, lumbarization or sacralization of vertebrae) in 11%, uncomplicated scoliosis in 2.7%, and spinal dysraphism in 4% including myelomeningocele, lipomeningocele, scimitar sacrum, and hemivertebrae, but only one patient demonstrated any evidence of neurologic dysfunction (Cadeddu et al, 1997). Thus although present in classic bladder exstrophy, symptomatic spinal anomalies appear rare.

Pelvic Floor Defects

Stec and colleagues (2001b), using 3D models created from CT scans of children with classic bladder exstrophy and normal age-matched controls, found that the puborectal slings were supporting two times more body cavity area than normal. The levator ani group is positioned more posteriorly in exstrophy patients, with 68% located posterior to the rectum and 32% anterior (vs. 52% posterior and 48% anterior in healthy controls) (Fig. 124–5). The levators are also rotated outward 15.5 degrees, and in the coronal aspect the levators are 31.7 degrees more flattened than normal. This deviation from normal makes the exstrophy puborectal sling more flattened than its normal conical shape. There was no significant difference in the length or thickness of these muscles between patients with exstrophy and normal controls.

Figure 124–5 Pelvic floor changes in the patient with exstrophy; levator ani group is positioned more posteriorly (68% located posterior to the rectum) compared with normal controls.

These new insights further elucidate the entire exstrophy defect, especially in regard to pelvic reconstruction. Interest in development of continence after primary closure in some patients has led to further investigation of the pelvic floor anatomy. Differences in orientation and anatomy of the pelvic floor musculature may directly affect development of continence following closure alone. The successful application of 3D magnetic resonance imaging (MRI) in anorectal anomalies has led to its use for the anatomic definition of the pelvic floor musculature in exstrophy. A comparison of 3D MRI in children with exstrophy before closure and in normal controls indicated that the levator ani group was less dome shaped and more irregular in those with exstrophy (Williams et al, 2004). Also, there was no relationship between the amount of pubic diastasis and the extent of disproportionate curvature of the levator ani group. In addition, Halachmi and colleagues (2003) reported on the postoperative appearance of the pelvic floor with 3D MRI. In two patients who had some degree of continence, the intrasymphyseal distance was noted to be shortest, the angle of the levator ani divergence sharpest, and the bladder neck most deeply positioned in the pelvis. Gargollo and colleagues (2005), reporting on a series of patients who had MRI before and after exstrophy closure, noted that the puborectalis angle in those with dry intervals was decreased compared with that before closure. These two studies correlate well with earlier findings of Gearhart and colleagues (1993c) showing that in the adult patients who were dry, the puborectalis angle was less than 65 degrees. These data reinforce the necessity for aggressive dissection and posterior placement of the posterior urethra and bladder and the role for osteotomy and pelvic fixation.

Abdominal Wall Defects

The triangular defect caused by the premature rupture of the abnormal cloacal membrane is occupied by the exstrophy bladder and posterior urethra. The fascial defect is limited inferiorly by the intrasymphyseal band, which represents the divergent urogenital diaphragm. This band connects the bladder neck and posterior urethra to the pubic ramus on anatomic study. The anterior sheath of the rectus muscle has a fanlike extension behind the urethra and bladder neck that inserts into the intrasymphyseal band. Investigations into the relationship of the rectus muscle and fascia to the urogenital diaphragm (Wakim and Barbet, 2002) have found no gross or histologic evidence of the presence of the striated sphincter. However, clear evidence of bladder musculature extending laterally to the pubis was found where it interdigitates with fibers from the rectus fascia forming the fibrous urogenital diaphragm (Wakim and Barbet, 2002). Gearhart and colleagues (1991) have shown the importance of radical incision of these fibers lateral to the urethral plate down to the level of the inferior pubic ramus and levator hiatus for the bladder and posterior urethra to be placed in a deep pelvic position. Data from failed exstrophy closures show these fibers to be intact in many patients at the time of reclosure.

At the upper end of the triangular fascial defect is the umbilicus. In bladder exstrophy, the distance between the umbilicus and the anus is always foreshortened. Because the umbilicus is situated well below the horizontal line of the iliac crest, there is an unusual expanse of uninterrupted abdominal skin. Although an umbilical hernia is usually present, it is usually of insignificant size. The umbilical hernia is repaired at the time of the initial exstrophy closure. Omphaloceles, although rarely seen in conjunction with bladder exstrophy, are frequently associated with cloacal exstrophy. Omphaloceles associated with classic bladder exstrophy-epispadias complex are usually small and can be closed at the time of bladder closure.

The frequent occurrence of indirect inguinal hernias is attributed to a persistent processus vaginalis, large internal and external inguinal rings, and lack of obliquity of the inguinal canal. Connolly and colleagues (1995), in a review of 181 children with bladder exstrophy, reported inguinal hernias in 81.8% of boys and 10.5% of girls. At the time of closure of the bladder exstrophy, these hernias should be repaired by excision of the hernial sac and repair of the transversalis fascia and muscle defect to prevent recurrence or a direct inguinal hernia. The contralateral side should also be explored because the incidence of synchronous or asynchronous bilaterality is high.

Anorectal Defects

The perineum is short and broad, and the anus is situated directly behind the urogenital diaphragm; it is displaced anteriorly and corresponds to the posterior limit of the triangular fascial defect. The anal sphincter mechanism is also anteriorly displaced and should be preserved intact in case internal urinary diversion is required in future management.

The divergent levator ani and puborectalis muscles and the distorted anatomy of the external sphincter contribute to varying degrees of anal incontinence and rectal prolapse. Anal continence is usually imperfect at an early age. In rare patients, the rectal sphincter mechanism may never be adequate to control the liquid content of the bowel. Rectal prolapse frequently occurs in untreated exstrophy patients with a widely separated symphysis. It is usually transient and easily reduced. Prolapse virtually disappears after bladder closure or cystectomy and urinary diversion. The appearance of prolapse in an infant is an indication to proceed with definitive management of the exstrophied bladder. If rectal prolapse occurs at any time after exstrophy closure, posterior urethral/bladder outlet obstruction should be suspected and immediate evaluation of the outlet tract by cystoscopy should be performed (Baker and Gearhart, 1998).

Male Genital Defect

The male genital defect is severe and is probably the most troublesome aspect of the surgical reconstruction, independent of the decision whether to treat with modern staged closure, combined closure, or a form of urinary diversion (Fig. 124–6). Formerly, it was thought that the individual corpora cavernosa were of normal caliber but appeared shorter because of the wide separation of the crural attachments, the prominent dorsal chordee, and the shortened urethral groove. However, Silver and colleagues (1997b) described the genital defect for the first time in bladder exstrophy in greater detail. MRI was used in adult men with bladder exstrophy and compared with results for age- and race-matched controls. They found that the anterior corporal length of male patients with bladder exstrophy was almost 50% shorter than that of normal controls (Fig. 124–7). However, although the posterior length of the corporal body was the same as in age-matched controls, the diameter of the posterior corporal segment was greater than in normal controls. It was also found on MRI that the diastasis of the symphysis pubis increased the intrasymphyseal and intercorporal distances, but the angle between the corpora cavernosa was unchanged because the corporal bodies were separated in a parallel fashion. Therefore the penis appears short not only because of the diastasis of the pubic symphysis, as thought in the past, but also because of marked congenital deficiency of anterior corporal tissue (Silver et al, 1997b). In a recent surgical anatomic study by Perovic and Djinovic (2007), precise description of the penile defect included (1) corporal bodies separated and triangular in shape; (2) a long convex ventral surface and a short wedge-shaped dorsal surface; and (3) neurovascular bundle length determined by its lie on the individual corporal bodies.

Figure 124–6 Newborn male with classic bladder exstrophy. Note the dorsal chordee, short urethral plate, and flattening of the scrotum.

Figure 124–7 Separation of the pubic bones in men with classic exstrophy combined with the congenital deficiency of the anterior corporal tissue leads to the shorter appearance of the penis. aCC, corpora cavernosa sustended angle; ACL, anterior corporal length; Cdiam, corpus cavernosum diameter; ICD, intercorporal distance; ISD, intersymphyseal distance; PCL, posterior corporal length; TCL, total corporal length.

A functional and cosmetically pleasing penis can be achieved when the dorsal chordee is released, the urethral groove lengthened, and the penis somewhat lengthened by mobilizing the crura in the midline.

In a study by Gearhart and colleagues (1993c), 13 adult men born with bladder exstrophy were evaluated with MRI of the pelvis to evaluate the size and configuration of the prostate and sex accessory organs. The volume, weight, and maximum cross-sectional area of the prostate appeared normal compared with published control values (Fig. 124–8). However, in none of the patients did the prostate extend circumferentially around the urethra, and the urethra was anterior to the prostate in all patients. Except for studies to document the presence of the prostate gland or its size, data do not exist concerning the function of the prostate gland in the patient with exstrophy. Silver and colleagues (1997a) reported free and total prostate-specific antigen levels for a group of adult men with bladder exstrophy. Although they were measurable, they were below the upper limits of established age-specific reference ranges for normal men. The vas deferens and ejaculatory ducts are normal in the exstrophy patient, provided they are not injured iatrogenically. Also, the mean seminal vesicle length in men with exstrophy was normal compared with published controls. Additional evaluation of the puborectalis muscle group was undertaken, and these muscles were found to be widely separated and provided lateral support of the prostate with a narrower puborectalis angle in those who were continent and had undergone prior iliac osteotomy.

Figure 124–8 A, Axial T2-weighted image of the midprostate in a 20-year-old continent patient with bladder exstrophy. Small arrowhead, lumen of the urethra; medium arrowhead, transitional zone; large arrowhead, peripheral zone. Curved arrow, fibrous band of the intersymphyseal bar. B, Sagittal T2-weighted image through the midprostate gland shows anterior urethra (double arrows) and posterior prostate gland. Intersymphyseal fibrous band (curved arrow) extends along the entire length of the prostate.

Autonomic innervation of the corpus cavernosum is provided by the cavernous nerves. These autonomic nerves are displaced laterally in patients with exstrophy (Schlegel and Gearhart, 1989). These nerves are preserved in almost all exstrophy patients because potency is preserved after surgery. However, retrograde ejaculation may occur after bladder closure and later bladder neck reconstruction.

Testis function has not been studied in a large group of postpubertal exstrophy patients, but it is generally believed that fertility is not impaired by testicular dysfunction. The testes frequently appear undescended in their course from the widened separated pubic tubercles to the flat, wide scrotum. Most testes are retractile and have an adequate length of spermatic cord to reach the scrotum without the need for orchiopexy.

Female Genital Defects

Reconstruction of the female genitalia presents a less complex problem than in the male (Fig. 124–9). The vagina is shorter than normal, hardly greater than 6 cm in depth, but of normal caliber. The vaginal orifice is frequently stenotic and displaced anteriorly, the clitoris is bifid, and the labia, mons pubis, and clitoris are divergent. The uterus enters the vagina superiorly so that the cervix is in the anterior vaginal wall. The fallopian tubes and ovaries are normal. The clitoral halves should be joined, and the two ends of the labia minora joined to make a fourchette at the time of primary closure. Vaginal dilatation or episiotomy may be required to allow satisfactory intercourse in the mature female. The defective pelvic floor may predispose mature females to the development of uterine prolapse, making uterine suspension necessary. This usually occurs after childbirth but can occur even in the nulliparous patient. When studied in a large adult female population, 10 of 56 women developed uterine prolapse at a mean age of 16 years. Six patients had been managed with reconstruction that included a posterior iliac osteotomy (Mathews et al, 2003). Mean age at the time of osteotomy was 2.1 years. The use of the modern combined anterior innominate and vertical iliac osteotomy early in life may lead to reduction in the incidence of later prolapse.

Figure 124–9 Newborn girl with classic bladder exstrophy. Notice the open urethral plate, bifid clitoral halves, and anterior displacement of the vaginal orifice.

Urinary Defects

At birth, the bladder mucosa may appear normal; however, ectopic bowel mucosa, an isolated bowel loop, or more commonly a hamartomatous polyp may be present on the bladder surface. If the bladder mucosa is not frequently irrigated with saline and protected from surface trauma by the interposition of some form of protective membrane before closure, cystic or metaplastic changes in the mucosal surface of the bladder may occur.

The size, distensibility, and neuromuscular function of the exstrophied bladder, as well as the size of the triangular fascial defect to which the bladder muscles attach, affect the decision to attempt repair. In the past several years, multiple basic science studies that further delineate the exact nature of the exstrophied bladder in the newborn have been published. One of the first papers to characterize the neuromuscular function of the bladder was published by Shapiro and colleagues (1985). In their work, muscarinic cholinergic receptor density and binding affinity were measured in control subjects and in patients with classic bladder exstrophy. The density of the muscarinic cholinergic receptors in both the control and exstrophy groups was similar, as was the binding affinity of the muscarinic receptor. Therefore it was thought by the authors that the neurophysiologic composition of the exstrophied bladder is not grossly altered during its anomalous development. Studies have investigated both the neural innervation of the newborn exstrophy bladder and its muscle and collagen content. Lee and colleagues (1996) looked at bladder biopsies obtained from 12 newborns with bladder exstrophy, compared with age-matched controls, and found an increase in the ratio of collagen to smooth muscle in the newborns with bladder exstrophy. In addition, using anticollagen antibodies, they evaluated various types of collagen in these bladders. Compared with normal control bladders, there was no statistical difference in the amount of type I collagen in the bladders of newborns with exstrophy at initial closure, but there was a threefold increase in type III collagen. Peppas and colleagues (1999) studied patients who gained adequate bladder capacities and were awaiting bladder neck reconstruction and found that the ratio of collagen to smooth muscle decreased markedly after a successful closure and infection-free follow-up. Lais and colleagues (1996) reported similar findings, but they measured the ratio of smooth muscle to collagen and found it increased after a successful closure.

In an extension of the studies just cited, Mathews and colleagues (1999b) looked at the number of myelinated nerves per field in the newborn bladders of normal subjects and those with exstrophy. The average number of myelinated nerves per field was reduced in the exstrophy bladders compared with controls, and the difference was statistically significant. This reduction in nerve fibers appears to be the result of a lack of small fibers with preservation of larger nerve fibers. In light of the findings already mentioned, it is believed that bladder exstrophy in a newborn probably represents an earlier stage in bladder development.

In a large study by Rosch and colleagues (1997) from Germany, multiple immunocytochemical and histochemical markers were examined in patients with epispadias or classic bladder exstrophy. These studies involved indirect immunocytochemistry for vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), substance P (SP), calcitonin gene–related product (CGRP), protein gene product (PGP) 9.5, and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd). No evidence of bladder muscle dysinnervation was found morphologically in any cases of classic bladder exstrophy. Cases of bladder exstrophy after failed reconstruction had muscle innervation deficiencies that increased subepithelial and intraepithelial innervation. Therefore although a newborn with bladder exstrophy may have a maturational delay in bladder development, these bladders have the potential for normal development after a successful initial closure.

When the bladder is small, fibrosed, inelastic, and covered with polyps, functional repair may be impossible (Fig. 124–10). Novak and colleagues (2005) investigated the pathology and malignant potential of the polyps found in these small bladders. Two types of polyps were observed, with some overlap in findings: fibrotic and edematous. Both were associated with overlying squamous metaplasia in approximately 50% of cases. Varying degrees of von Brunn nests, cystitis cystica, and cystitis glandularis were noted. Cystitis glandularis was noted in a higher percentage of secondary closures. Because of the potential risk of adenocarcinoma associated with cystitis glandularis, future surveillance of these patients with urine cytology and cystoscopy as they enter adulthood is recommended. The more normal bladder may be invaginated, or it may bulge through a small fascial defect, indicating the potential for satisfactory capacity after successful initial closure. Also, not until examination under anesthesia can the true defect be adequately evaluated because bladders that appear small in the nursery may have a good bit of bladder sequestered below the fascial defect. The depth of this extension often cannot be appreciated unless the infant is totally relaxed under anesthesia.

Figure 124–10 Small inelastic bladder template covered with polyps, unsuitable for primary closure.

Bladder function was assessed in a group of continent exstrophy patients with normal reflexive bladders. Normal cystometrograms were obtained in 70% to 90% of cases (Toguri et al, 1987). Diamond and colleagues (1999), looking at 30 patients with bladder exstrophy at various stages of reconstruction, found that 80% of patients had compliant and stable bladders before bladder neck reconstruction. After bladder neck reconstruction, approximately half of the patients maintained normal bladder compliance and a lesser number maintained normal stability. The authors believed that compliance and stability were impaired after bladder neck reconstruction and that 25% of patients with exstrophy may maintain normal detrusor function after reconstruction. In an earlier paper by Hollowell and colleagues (1993), 13 of 21 children revealed involuntary contractions and only 4 revealed stable bladders before bladder neck reconstruction. Also, 7 of 21 had increased pressures (>10 cm H₂O), suggesting decreased compliance. The difference in findings between these two urodynamic studies is difficult to explain from an experimental perspective. However, standardized methods of bladder neck repair do not exist, and these differences may be reflected in the different urodynamic findings after bladder neck repair in these two groups of patients.

Several interesting aspects of the microstructure of the bladder in children with bladder exstrophy were noted by Mathews and colleagues (2004) using specimens obtained from children with bladder exstrophy at various stages of reconstruction (newborn bladder closure, bladder neck reconstruction, augmentation cystoplasty). At the cellular level, important differences were noted. Caveoli, which are important intracellular structures involved in cell-cell signaling, were found to be normal in the patients with a successful closure and improvement in bladder capacity and significantly lacking in the patients who required eventual augmentation cystoplasty (Fig. 124–11). In addition, the ultrastructure of cells in the patients in whom closure failed was noted to be abnormal.

Figure 124–11 Ultrastructural changes noted in the exstrophic bladder. A, Normal muscle and nerve profiles in the newborn bladder. B, Following failure of prior closure, significant deterioration is noted with increased intercellular collagen and degenerating muscle and few nerve profiles.

(From Matthews RI, Wills M, Perlman E, et al. Neural innervation of the newborn exstrophy bladder: an immunohistological study. J Urol 1999;162:506.)

The urinary tract is usually normal, but anomalous development does occur. Horseshoe kidney, pelvic kidney, hypoplastic kidney, solitary kidney, and dysplasia with megaureter are all encountered in these patients. The ureters have an abnormal course in their termination. The peritoneal pouch of Douglas between the bladder and the rectum is enlarged and unusually deep, forcing the ureter down laterally in its course across the true pelvis. The distal segment of the ureter approaches the bladder from a point inferior and lateral to the orifice, and it enters the bladder with little or no obliquity. Therefore reflux in the closed exstrophy bladder occurs in 100% of cases, and subsequent surgery is usually required at the time of bladder neck reconstruction. If excessive outlet resistance is gained at the time of either initial closure or combined epispadias and bladder exstrophy closure and recurrent infections are a problem even with suppressive antibiotics, ureteral reimplantation or Deflux injection is required before bladder neck reconstruction.

Exstrophy Complex and Variants

Exstrophy complex includes a spectrum of anomalies ranging from epispadias to cloacal exstrophy. Many variations in anatomy and types of defects have been noted. Because there is probably a common embryologic origin for all of these defects, they all share many or some of the defects noted in the three major components of the complex—skeletal, urinary, and genital. The presence of a characteristic musculoskeletal defect of the exstrophy anomaly with no major defect in the urinary tract has been named “pseudoexstrophy” (Marshall and Muecke, 1968). Predominant characteristics include an elongated, low-set umbilicus and divergent rectus muscles that attach to the separated pubic bones (Fig. 124–12). In this variant, the mesodermal migration has been interrupted in its superior aspect only, thus wedging apart the musculoskeletal elements of the lower abdominal wall without obstructing the formation of the genital tubercle.

Figure 124–12 A and B, Pseudoexstrophy in an adult male patient. Musculoskeletal deformity characteristic of the exstrophy complex is present, but the urinary tract is intact.

In the superior vesical fissure variant of the exstrophy complex, the musculature and skeletal defects are exactly the same as those in classic exstrophy; however, the persistent cloacal membrane ruptures only at the uppermost portion, and a superior vesical fistula that actually resembles a vesicostomy results. Bladder extrusion is minimal and is present only over the normal umbilicus (see Fig. 124–1B).

In a large review of an exstrophy database of more than 815 patients, Lowentritt and colleagues (2005) reported 25 exstrophy complex variants, 6 of which were cloacal exstrophy variants. Continence rates after bladder neck repair were compatible with classic exstrophy (Fig. 124–13). Three cases were reported by Arap and Giron (1986) in which the patients had classic musculoskeletal defects, and two of the three were continent. Of the two male patients, one had an associated complete epispadias and the other had a completely normal penis. Therefore the external genital manifestations in duplicate exstrophy can be quite variable.

Figure 124–13 A to C, Duplicate exstrophy in a boy with an intact lower urinary tract.

In addition to pseudoexstrophy, superior vesical fissure, and duplicated exstrophy, isolated occurrences of a fourth entity, “covered exstrophy,” have been reported (Cerniglia et al, 1989). This has also been referred to as split symphysis variant. A common factor in these patients is the presence of musculoskeletal defect associated with classic exstrophy but no significant defect of the urinary tract. Chandra and colleagues (1999) reported a covered exstrophy with incomplete duplication of the bladder. However, in most cases of covered exstrophy (Narasimharao et al, 1985; Cerniglia et al, 1989), there has been an isolated ectopic bowel segment present on the inferior abdominal wall near the genital area, which can be either colon or ileum with no connection with the underlying gastrointestinal tract and only epispadias in the male. A patient seen at our institution had the standard appearance of most split symphysis variants, and one could actually see the bladder through a thin membrane of lower abdominal skin. Although all of the classic musculoskeletal defects of exstrophy were present, there was no isolated ectopic bowel segment present on the lower abdominal wall (Fig. 124–14). These patients should all undergo formal exstrophy closure at birth.

Figure 124–14 Skin-covered exstrophy in a female patient. Note urethral sound in the bladder and the subcutaneous position below the skin of the abdominal wall. No bowel is sequestered on the abdominal wall, as has been reported in some patients with this variant.

There are two different forms of duplication, anteroposterior duplication and side-by-side duplication. The first form is considered a duplicate exstrophy with a patch of everted bladder mucosa on the anterior abdominal wall with a second bladder lying in the pelvis. The ureters attach to the closed bladder, rendering the superficial mucosa dry (see Fig. 124–13). The mainstay of treatment has been resection of the ectopic mucosa and closure of the abdominal wall defect. The other form of duplication involves patients who have two separately formed bladder halves in a left-right orientation with a midline septum between the bladders containing muscle. Each bladder has its own ureter and an intact sphincter. Oftentimes there is diastasis of the pubis and rectus muscle.

Selection of Patients for Immediate Closure

Successful treatment of exstrophy with functional closure demands that the potential for success in each child be carefully considered at birth. The size and functional capacity of the detrusor muscle are important considerations for the eventual success of functional closure. Correlation between apparent bladder size and the potential bladder capacity must not be confused. In minor grades of exstrophy that approach the condition of complete epispadias with incontinence, the bladder may be small yet may demonstrate acceptable capacity, either by bulging when the baby cries or by indenting easily when touched by a sterile gloved finger in the operating room with the child under anesthesia. Sometimes a good bit of previously unappreciated bladder can be discovered behind the fascia under examination with anesthesia (Gearhart and Jeffs, 1998). Once the bladder is relieved of surface irritation and repeated trauma, the small bladder can enlarge and increase in capacity with the absence of sphincter activity and with minimal outlet resistance. The exstrophied bladder that is estimated at the time of birth to have a capacity of 5 mL or more and demonstrates elasticity and contractility can be expected to develop useful size and capacity after successful bladder, posterior urethral, and abdominal wall closure with early epispadias repair (Gearhart and Jeffs, 1998).

Small Exstrophy Bladder Unsuitable for Newborn Closure

A small, fibrotic bladder patch that is stretched between the edges of the small triangular fascial defect without elasticity or contractility cannot be selected for the usual closure procedure (Gearhart and Jeffs, 1998) (see Fig. 124–10). Examination with the patient under anesthesia may at times be required to assess the bladder adequately, particularly if considerable edema, excoriation, and polyp formation have developed between birth and the time of assessment. Decisions regarding the suitability of bladder closure or the need for waiting should be made only by surgeons with a great deal of experience in the exstrophy condition (Gearhart and Jeffs, 1998). Neonatal closure, even when the bladder is small, can allow assessment of bladder potential, provides an initial step in genital reconstruction, and is helpful in reassuring the family. Some conditions preclude primary closure, including penoscrotal duplication, ectopic bowel within the extruded bladder (a relative contraindication), a hypoplastic bladder, and significant bilateral hydronephrosis.

In a recent review by Lakshmanan and colleagues (2008) of cases at our institution, it was found on initial judgment that the bladder was too small for closure in 34 patients evaluated at birth. There were 27 males and 6 females who underwent delayed closure at a mean age of 13.2 months. Osteotomy was performed on 29 (85%). All had a successful delayed primary closure. Eleven (41%) of the boys had a simultaneous epispadias repair. Sixty one percent developed sufficient capacity for bladder neck reconstruction and 39% are continent. Compared with newer data by Novak and colleagues (2010), these rates are over double the continence rates seen in bladder neck repair after failed primary closure and successful secondary closure.

Thus waiting for the bladder template to grow for 6 to 12 months in the child with a small bladder is not as risky as submitting a small bladder template to closure in an inappropriate setting, resulting in dehiscence and allowing the fate of the bladder to be sealed at that point. If the bladder does not grow to sufficient size after 6 to 12 months, other options include excision of the bladder and a nonrefluxing colon conduit or ureterosigmoidostomy. Another alternative involves urinary diversion with a colon conduit and placing the small bladder inside to be used later for the posterior urethra in an Arap-type procedure. Lastly, if the bladder is small and the presentation is for late primary closure, bladder augmentation, ureteral reimplantation, and an outlet procedure, in addition to a continent urinary stoma, can be considered.