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Cloacal exstrophy

Cloacal exstrophy is a rare and severe congenital malformation, constituting the most extreme end of the exstrophy-epispadias spectrum, marked by a prominent infraumbilical defect exposing a cecal plate continuous with the , paired hemibladders separated by an appendiceal remnant, and frequently associated and —collectively termed the OEIS complex when spinal defects are present. This defect stems from early embryologic failure of mesenchymal ingrowth to support the cloacal membrane, resulting in its rupture and disrupted caudal mesodermal migration, which impairs development of the lower urinary, genital, and gastrointestinal tracts as well as the pelvic bones and . Incidence estimates range from 1 in 200,000 to 400,000 live births, with survival rates now approaching 100% due to advances in neonatal care and staged surgical interventions, though affected individuals often contend with lifelong complications including renal anomalies, neurogenic , , inadequate genital development (particularly phallic in genetic males), and orthopedic deformities. Initial management typically involves primary closure within days of birth to protect exposed viscera, followed by multistage reconstructions to separate urinary and intestinal streams, achieve continence via augmentation or diversion, and reconstruct genitalia, demanding coordinated multidisciplinary expertise from pediatric urologists, surgeons, orthopedists, and gastroenterologists. Notable challenges include high rates of surgical revisions—often exceeding a dozen procedures—and debates over gender assignment in cases of severe genital ambiguity, where some genetic males reassigned female at birth exhibit later , underscoring the influence of anatomical adequacy over chromosomal sex alone in .

Definition and Clinical Features

Core Anatomical Defects

Cloacal exstrophy manifests as a severe midline defect characterized by the of urinary and intestinal structures, forming the hallmark of the OEIS complex—, exstrophy of the (involving the and ileocecal plate), and . The infraumbilical defect exposes two hemibladders, which are everted and separated by a central, prolapsed cecal plate representing the exstrophied , often with an appended terminal protruding in an "elephant trunk" configuration due to the unfused ileocecal region. The terminates blindly as a short, atretic colon within the , precluding anal formation. Accompanying the visceral exstrophy is marked pubic diastasis, with separation of the pubic rami typically measuring 4-6 cm at birth, resulting from failed mesenchymal fusion and outward rotation of the innominate bones. Genital malformations are integral to the defect and -dependent. In individuals with a 46,XX , structures include a bifid with separated halves, widely splayed , and often duplicated vaginas associated with Müllerian duplication (such as in approximately 70% of cases). In those with a 46, , anomalies feature , a short and bifid (hemiphallus) with dorsal , and broad scrotal separation, reflecting severe phallic .

Associated Anomalies

Cloacal exstrophy is frequently accompanied by spinal dysraphism, occurring in approximately 83% of cases, which encompasses a spectrum of defects such as lipomyelomeningocele, , and myelomeningocele. These anomalies arise from disrupted caudal and can lead to neurological deficits, including lower extremity weakness, , and bowel/bladder dysfunction, thereby compounding the baseline challenges in mobility and continence. Orthopedic malformations are prevalent, including pelvic asymmetry, in up to 23% of hips evaluated, foot deformities such as , and later-onset or pelvic obliquity due to unbalanced pelvic ring development and spinal involvement. These structural issues impair , stability, and spinal alignment, often necessitating orthopedic monitoring to mitigate progressive deformity and support ambulation. Renal and upper urinary tract anomalies affect around 60% of patients, manifesting as , , ureteral duplication, pelvic kidneys, or , which heighten risks of recurrent infections, scarring, and diminished renal function over time. Cardiac defects and chromosomal abnormalities occur infrequently, with no elevated incidence of the latter beyond sporadic cases like trisomy 13. Reproductive physiology is profoundly disrupted by genital malformations, resulting in impaired ; while rare assisted pregnancies have been documented in select cases of cloacal exstrophy, natural remains unproven due to uterine anomalies in females and phallic deficiencies in males.

Etiology and

Pathogenetic Mechanisms

Cloacal exstrophy originates from disruptions in early embryonic development of the caudal region, particularly involving the , a transient structure composed of and without intervening . During gestational weeks 4 to 6, normal embryogenesis requires lateral body wall folds to migrate ventrally and incorporate around the , enabling its controlled rupture and separation of urogenital and structures. Failure of this mesenchymal ingrowth results in membrane persistence, overdistension, and premature rupture, exposing infraumbilical midline elements and preventing abdominal wall closure. This defect halts the concomitant caudal migration of the urorectal septum, which normally partitions the into and anorectal components, yielding a spectrum of malformations including hemibladders flanking a cecal plate. The condition's is multifactorial, with genetic contributions evident but lacking a singular causative locus; most cases arise sporadically via mutations rather than . Animal models implicate disruptions in signaling pathways, such as (e.g., Gli3 mutants) and transcription factors (e.g., Alx4), which regulate mesenchymal migration and midline fusion, mirroring human phenotypes of incomplete and variability. In humans, rare copy number variants and missense mutations (e.g., in SLC20A1) have been identified in subsets of patients, suggesting heterogeneous molecular pathways, but genome-wide studies confirm no high- alleles predominate. Familial recurrence is exceptional, often tied to gonadal mosaicism for dominant variants rather than autosomal recessive or polygenic risks. Environmental teratogens lack empirical confirmation as causal agents; despite sporadic hypotheses linking maternal or exposure to exstrophy-epispadias spectrum risks, no robust data isolate these for cloacal exstrophy specifically, underscoring developmental instability over exogenous triggers. This aligns with the disorder's isolation from syndromic contexts beyond rare overlaps, prioritizing intrinsic embryological vulnerabilities in causal reasoning.

Incidence, Prevalence, and Risk Factors

Cloacal exstrophy is an exceedingly rare congenital malformation, with a historical estimated at 1 in 200,000 to 400,000 live births. More recent epidemiological analyses have proposed a higher incidence, ranging from 1 in 50,000 to 200,000 live births, potentially reflecting improved detection and reporting. The condition exhibits no substantial geographic or racial disparities, occurring at comparable rates across populations, including and other regions. Affected individuals display a predominance, with a male-to-female ratio of approximately 1.4:1 to 2:1, though earlier studies occasionally reported higher female rates, possibly due to diagnostic or ascertainment biases. The is predominantly sporadic, with familial recurrence exceedingly rare at less than 1%, underscoring limited in most cases. No strong modifiable risk factors have been consistently identified, though shows a weak in broader exstrophy-epispadias spectrum disorders. The incidence of chromosomal anomalies is not elevated beyond general population levels, and routine karyotyping is not diagnostically indicated. Potential contributors such as assisted reproductive technologies remain unproven and correlative at best.

Diagnosis

Prenatal Detection

Prenatal detection of cloacal exstrophy is primarily achieved through fetal ultrasound between 12 and 20 weeks of gestation, with major criteria including nonvisualization of the urinary bladder, a large midline infraumbilical anterior abdominal wall defect, and a protruding omphalocele. Additional sonographic signs encompass splaying of the iliac bones or pubic rami, spinal defects such as myelomeningocele or scoliosis, and a narrowed thorax. Elevated maternal serum alpha-fetoprotein levels during second-trimester screening for neural tube defects can also signal the condition, particularly when associated with omphalocele or ventral wall anomalies. Fetal (MRI) complements for confirmation, offering superior soft-tissue resolution to delineate cloacal malformations, such as the exstrophic plate, exposed intestinal segments, and precise extent of spinal or pelvic involvement. MRI is especially valuable when findings are equivocal, as in distinguishing cloacal from by visualizing everted bowel or non-visualized remnants. Amniocentesis for karyotyping is routinely performed following suspicious imaging to evaluate chromosomal status and fetal sex, given the frequent ambiguity of external genitalia in affected cases; normal karyotypes (e.g., 46, or 46,) are common, informing early discussions on gender assignment. Advancements in routine scans have elevated prenatal detection rates to 78-82% in high-volume referral centers, compared to lower historical figures, enabling timely multidisciplinary counseling on , delivery at specialized facilities, and potential termination options where legally available.

Postnatal Assessment

Upon delivery, the newborn with cloacal exstrophy requires immediate stabilization, including if compromised, , and coverage of exposed viscera—such as the , hemibladders, and prolapsing —with sterile occlusive dressings like or silicone gel to prevent , , and infection. The characteristic physical findings include a midline infraumbilical defect with , two exstrophied halves separated by a central ileal plate resembling a rudimentary , anteriorly displaced and , wide pubic diastasis, and often ambiguous external genitalia with a short broad or bifid . These features confirm the in most cases undiagnosed prenatally, prompting to a multidisciplinary team for associated anomaly screening. Initial imaging prioritizes plain anteroposterior pelvic radiographs to evaluate and spinal alignment, alongside spinal to detect dysraphism, which affects 97-98% of cases and may necessitate MRI for detailed assessment of tethered cord or myelomeningocele. Renal and follows to assess upper urinary tract dilation, , or ectopic kidneys, with voiding cystourethrogram (VCUG) if feasible to identify ; baseline serum electrolytes and creatinine gauge renal function. is indicated for suspected cardiac defects, occurring in up to 40% via VACTERL associations. In instances of genital ambiguity, urgent karyotyping establishes chromosomal sex (typically 46,XX or 46,XY, though mosaicism possible), guiding initial gender assignment and avoiding assumptions based on alone; additional hormonal assays may rule out conditions like . No standardized postnatal grading system universally applies to bladder or bowel plates, though defect severity influences surgical timing, with smaller omphaloceles and viable bladder mucosa favoring earlier closure. Prophylactic antibiotics and nutritional support via total bridge to definitive care.

Management

Initial Neonatal Care

Upon delivery, the exposed viscera—including the , hemibladders, cecal plate, and prolapsed —must be immediately protected to prevent , , and . This is achieved by covering the defects with saline-moistened sterile dressings or occlusive wraps, supplemented by transparent adhesive barriers to separate the halves and cecal plate from fecal contamination, while using porous barriers for the . Fluid resuscitation via intravenous access is initiated promptly to maintain hemodynamic stability and balance, alongside prophylactic broad-spectrum antibiotics to mitigate risks of urinary tract and infections. Patients are kept nil per os () initially, with total provided to support growth, wound healing, and metabolic demands, given the gastrointestinal tract's involvement and anticipated surgical delays. Decompression of the bowel and any hydrocolpos is addressed through temporary measures such as catheters to relieve pressure and prevent complications like or distension, while avoiding hasty attempts at full of defects to reduce risks of inadequate or postoperative dehiscence. These steps typically occur in a (NICU) setting, with stays averaging 2–3 weeks prior to staged interventions. A multidisciplinary team, comprising neonatologists, pediatric urologists, colorectal surgeons, and additional specialists (e.g., orthopedists for pelvic instability), coordinates care from birth to optimize physiological support and plan subsequent procedures, addressing associated anomalies like spinal dysraphism or renal impairment early through and . This approach prioritizes survival and condition stabilization over immediate reconstruction, particularly in cases complicated by prematurity, , or cardiac issues, without evidence of heightened infection rates from deferral.

Multistage Surgical Reconstruction

The multistage surgical reconstruction of cloacal exstrophy prioritizes separation of urinary and gastrointestinal tracts, restoration of integrity, and achievement of continence through phased interventions, typically beginning in the neonatal period. This approach has evolved to optimize outcomes by addressing the exstrophied halves, exposed cecal plate, and associated , with empirical data indicating superior closure rates compared to single-stage attempts. The initial neonatal stage, performed within 48–72 hours of birth, focuses on gastrointestinal separation and stabilization. Procedures include excision or of the , often using a or if immediate primary is not feasible, and separation of the cecal plate from the hemibladders to create an end , tubularizing the to rescue length for potential future use. halves are approximated into a posterior plate, with ureteral catheters placed to protect the upper tracts, though definitive is deferred. This stage aims to prevent infection and while preserving tissue for later reconstruction. Subsequent stages, typically at 6 months to 2 years, involve closure with abdominal wall reconstruction to form a functional . If bladder capacity remains inadequate, augmentation via ileocystoplasty or gastrocystoplasty is performed, often combined with creation of a catheterizable urinary channel (e.g., using the for ) to facilitate clean intermittent catheterization. Colorectal pull-through is considered selectively for reconstruction when sufficient colon length (e.g., ≥64 cm) supports potential fecal continence, restoring bowel continuity after initial . Long-term data show urinary continence in approximately 71% of patients following multiple procedures, though 73% of older patients require ongoing catheterization; survival exceeds 95% with this protocol.

Orthopedic and Neurosurgical Aspects

Orthopedic management in cloacal exstrophy focuses on pelvic osteotomies to narrow the severe pubic diastasis, typically exceeding 6 cm, thereby enabling tension-free and urogenital . Techniques include bilateral anterior innominate osteotomies, posterior iliac cuts, or combined approaches, often integrated into staged reconstructions alongside urologic procedures. Staged osteotomies, performed 2–3 weeks before definitive , facilitate hemipelvic approximation without elevating complication risks compared to single-stage methods. These interventions markedly improve closure success; in primary cases without , complication rates reached 89%, whereas incorporation of reduced this to 17%. Neurosurgical evaluation addresses the near-universal spinal dysraphism, present in 97–98% of patients, encompassing (incidence up to 100%), lipomyelomeningocele, myelocystocele, or myelomeningocele. Routine prenatal or postnatal spinal and MRI screening guides interventions, such as early myelomeningocele repair, symptomatic cord untethering to avert neurological decline, or ventriculoperitoneal shunting for associated with myelodysplasia. Detethering yields functional gains, including urodynamic enhancements in voiding. Adolescent orthopedic corrections target progressive pelvic obliquity, hip instability, or via osteotomies or , emphasizing early multidisciplinary timing to optimize outcomes and mitigate reliance; long-term data show 36.5% independent ambulation without aids, though 34.9% remain wheelchair-dependent. Procedure-related complications, including pin-site infections, hardware migration, and , affect 56.8% of cloacal exstrophy patients—higher than the 38.5% in classic —necessitating vigilant postoperative monitoring integrated with urologic stages.

Gender Assignment Controversies

Historical Reassignment Practices

In the mid-20th century, the management of 46,XY individuals with cloacal exstrophy was heavily influenced by psychologist 's theories, which emphasized environmental and social factors over innate biological determinants in shaping . , working primarily from the 1950s through the 1970s at , advocated for early surgical and rearing interventions in cases of severe phallic inadequacy, arguing that gender could be effectively molded by postnatal socialization within a critical developmental window. This perspective justified reassigning genetic males to female sex through procedures such as , , and , followed by female socialization, on the grounds that an inadequately formed rendered male rearing untenable and that female anatomy could be more readily approximated surgically. This approach became the standard protocol for conditions including cloacal exstrophy, where 46, males typically present with or severe phallic alongside undescended testes and other anomalies. From the until the late , neonatal female sex assignment was routinely performed in the majority of such cases, with one clinical series documenting 14 out of 16 genetic males (approximately 88%) reassigned female shortly after birth, involving gonadectomy within weeks and subsequent feminizing . These practices were embedded in broader management guidelines that presumed gender identity's high plasticity, prioritizing cosmetic and functional outcomes in external genitalia over chromosomal (46,), gonadal (testicular), or prenatal imprinting influences. The paradigm's theoretical foundation rested on the assumption that markers could be overridden by rearing, sidelining evidence of fetal testosterone's role in masculinizing structures and behaviors. Money's reports, such as a 1975 case of successful female reassignment following penile , extrapolated to congenital conditions like cloacal exstrophy, despite the latter involving intact gonadal and hormonal profiles from early gestation. This prioritization of phenotypic appearance and surgical feasibility over underlying reflected a nurture-dominant view that later faced scrutiny for underweighting causal biological realities in sex differentiation. By the early 2000s, surveys of pediatric urologists indicated a nascent shift away from this near-universal assignment, though it persisted in some centers trained under earlier protocols.

Evidence on Outcomes and Gender Identity

A pivotal study by Reiner and Gearhart examined 16 genetic males (46,XY) with cloacal exstrophy, of whom 14 were assigned and reared as females neonatally, involving and surgical feminization. At follow-up ages 5 to 16 years, 8 of these 14 (57%) unequivocally identified as male, with 6 self-reassigning to male and the remaining 2 (originally reared male) also identifying as male; those identifying male exhibited behaviors, including attraction to females. The study concluded that prenatal androgen exposure likely exerts a dominant influence on male , overriding postnatal and rearing as female. A subsequent by Meyer-Bahlburg analyzed outcomes in female-raised 46,XY individuals across cloacal exstrophy, penile agenesis, and penile ablation, finding substantial male identification rates despite early and consistent female rearing; specifically for cloacal exstrophy cases, male persisted in a , supporting the role of prenatal androgens in over environmental factors. These findings indicate that female reassignment does not reliably produce female identity, with reversal or dissatisfaction rates approaching or exceeding 50% in tracked cohorts, contrasting with non-reassigned males who consistently aligned with their genetic sex without reported identity discordance. Reassigned individuals faced additional challenges, including in a (e.g., some persisting as female but expressing discomfort) and functional limitations such as due to absent female reproductive structures and suboptimal sexual outcomes post-vaginoplasty, including inadequate and satisfaction. Non-reassigned males, while contending with phallic inadequacy, demonstrated better psychosexual alignment, with male-typical orientation and no of identity reversal. Long-term data underscore that genetic and hormonal factors predominate in gender identity determination, rendering socialization-based reassignment empirically unsupported for producing stable identity in 46, cases.

Modern Approaches and Debates

Since the early 2000s, management of assignment in cloacal exstrophy has shifted toward retaining the determined by , particularly for 46, individuals, who are now predominantly raised as with plans for in or adulthood using techniques such as the radial forearm free flap to construct functional genitalia. This change reflects empirical evidence from longitudinal studies demonstrating that prenatal imprints a in 46, patients, often overriding postnatal rearing influences, rendering female reassignment ineffective for long-term adjustment. For 46,XX cases, which comprise about one-third of patients and typically present with intact Müllerian structures, assignment and rearing remain standard, with surgical focus on vaginal and uterine preservation where feasible. Debates persist among some clinicians advocating for reassignment in 46,XY cases based on outdated models prioritizing surgical feasibility over biological determinants, despite surveys of pediatric urologists showing over 90% favoring male assignment by 2016, a marked increase from prior decades. These approaches emphasize multidisciplinary for parents, incorporating on androgen imprinting risks and requirements for lifelong endocrine and psychological tracking to monitor identity stability. A review underscores karyotype-driven decisions as evidence-based, critiquing narratives of inherent in this cohort as unsupported by data, where 46,XY individuals exhibit robust male-typical behaviors and identities irrespective of early interventions. This stance aligns with causal mechanisms of , prioritizing empirical outcomes over speculative psychosocial theories, though gaps remain in standardized protocols for timing and preservation in retained males.

Prognosis and Long-term Outcomes

Survival Rates and Quality of Life

Advances in neonatal , nutritional , and multistage surgical have resulted in rates approaching 100% for infants born with cloacal exstrophy since the 1970s. In a of 50 patients treated over 25 years, overall reached 98%, with the single preoperative occurring at another facility. Functional outcomes include variable achievement of urinary continence, often requiring augmentation, continent diversion, and clean intermittent catheterization; success rates typically range from 50% to 70% in specialized centers, though long-term incontinence remains common without ongoing management. Ambulation is attainable for most patients following pelvic osteotomies and orthopedic interventions, enabling independent mobility in the majority, albeit sometimes with assistive devices due to inherent pelvic instability. Bowel continence is frequently managed via programs or stomas, with acceptable control in a substantial subset. Quality of life assessments indicate that is feasible for many adults, with tracked cohorts demonstrating and occupational engagement comparable to peers in some studies. is evident, as 76% of adult women in one survey reported satisfaction with social lives and minimal professional disruption from their condition. However, lifelong dependencies such as stomas, urinary appliances, and —particularly in males with genital reconstruction—persist, alongside variable ; is generally absent without assisted reproduction, though sexual activity occurs in varying degrees among survivors. Overall, while challenges limit full normalcy, multidisciplinary care supports substantive life achievements and reported .

Persistent Challenges and Complications

Patients with cloacal exstrophy face persistent urinary challenges, including incomplete continence despite reconstructive efforts, with long-term incontinence rates reported as high in adolescent and cohorts, often necessitating lifelong intermittent catheterization or diversion in over 90% of cases.00023-1/abstract) Recurrent urinary tract infections (UTIs) remain common due to anatomical irregularities and augmentation procedures, elevating the risk of renal deterioration, including progression to end-stage renal disease in some patients. Sexual and reproductive dysfunction constitutes a near-universal complication, with prevalent owing to malformed genitalia and associated anomalies; fewer than 10% of affected females achieve , while males exhibit consistent sterility linked to underdeveloped structures. and further impair function, stemming directly from pelvic and urogenital defects rather than secondary factors. Mobility limitations arise from orthopedic sequelae, such as pelvic instability and spinal anomalies, with approximately 35% of patients remaining wheelchair-dependent into adulthood due to unresolved diastasis or neurological deficits.00550-X/abstract) These issues, compounded by risk factors for from immobility and potential metabolic effects of urinary diversions, necessitate ongoing monitoring. Psychosocial burdens, including elevated rates of anxiety and in over 50% of patients, correlate with chronic physical demands like frequent medical interventions and (affecting 27%), rather than isolated identity concerns; family caregivers experience substantial strain from sustained care responsibilities.00550-X/abstract) Comprehensive, multidisciplinary follow-up is essential lifelong to mitigate these anatomical-driven complications and support functional adaptation.

Historical Development

Early Case Reports

Cloacal exstrophy was first described in by French surgeon Alexis Littre, who documented a newborn with exposed and intestinal mucosa protruding through a midline defect, terming it a form of ectopia. Early accounts emphasized the grotesque anatomical exposure, including hemibladders flanking a cecal plate and , but lacked insight into underlying embryologic failure of cloacal membrane incorporation. Nineteenth-century reports remained anecdotal and postmortem, noting associated and spinal anomalies in isolated cases, with no interventions achieving viability beyond days due to rampant , , and fluid loss from exposed viscera. These observations highlighted the condition's incompatibility with life outside controlled environments, as neonates invariably perished from or overwhelming bacterial invasion absent modern antibiotics or supportive care. Prior to the , cloacal exstrophy was deemed uniformly fatal, with rudimentary attempts at wound coverage failing against the multifocal defects compromising gut integrity and renal function. The first reported long-term survival emerged in via staged operative management, marking a pivot from fatalistic descriptions to potential causal dissection of ventral wall dysmorphogenesis. By the 1970s, accumulating survivals enabled pattern recognition across cases, culminating in Carey et al.'s 1978 delineation of the OEIS complex—encompassing , exstrophy, , and spinal defects—as a cohesive spectrum rather than disparate anomalies. This reframing spurred etiologic focus on early embryonic cloacal partitioning errors, diverging from prior rote anatomical catalogs.

Evolution of Surgical Techniques

The initial surgical closures for cloacal exstrophy were attempted in the , marking the transition from uniformly fatal outcomes to feasible , with the first reported long-term survival following a three-stage intervention in 1960. Pioneers such as Robert D. Jeffs at developed foundational staged approaches for exstrophy repairs, extending these to cloacal cases by emphasizing closure, bladder plate approximation, and intestinal separation to mitigate and risks that previously drove mortality rates above 50%. Concurrent efforts by J.C. Molenaar in focused on primary neonatal closures, incorporating hindgut tubularization and to address the exposed cecal plate and hemibladders, though early techniques faced high dehiscence rates due to inadequate pelvic fixation. By the 1980s, standardized multi-stage protocols emerged, incorporating pelvic osteotomies to achieve approximation and reduce tension on closures, a technique refined by Paul D. Sponseller, Robert Jeffs, and John P. that improved primary closure success from under 50% to over 80% in select centers. These advancements, including bilateral anterior innominate osteotomies combined with , addressed the severe pelvic diastasis characteristic of cloacal exstrophy, lowering to below 10% through better hemodynamic stability and wound healing.00446-8/abstract) The focus shifted toward functional urinary and bowel reconstruction, with initial stages prioritizing repair, formation, and bladder preservation over immediate cosmetic genital alignment. In the 1990s and 2000s, continent urinary diversions such as appendicovesicostomy () became integral to later stages, enabling catheterizable channels for neck reconstruction and achieving dryness in up to 70% of cases when combined with prior closures, though requiring multiple revisions for . Overall mortality plummeted to under 5% by the early 2000s, driven by these empirical refinements in staging—separating cecal plate from halves, rescuing for potential fecal continence via enemas, and augmenting small-capacity s—prioritizing renal protection and function over idealized aesthetics. Contemporary techniques in the incorporate robotic assistance for precise and urethral reconstructions in secondary stages, reducing operative times and complications in experienced hands, while experimental regenerative approaches using acellular matrices for augmentation aim to enhance without synthetic grafts. These evolutions underscore a trajectory of iterative, data-driven modifications yielding near-100% survival and improved long-term continence rates of 50-60% with augmentation, though persistent challenges like outlet resistance necessitate lifelong catheterization in most patients. 29053-8/abstract)