Course objectives: After completing this course, the participant should be able to:
1. Recognize ultrasound findings for various abdominal wall defects.
2. Understand the outcomes of pregnancies affected by abdominal wall defect.
3. Use proper scanning techniques to diagnose the anomaly.
Target audience: Physicians, sonographers and others who perform and/or interpret OB ultrasound.
Exstrophy of the urinary bladder is a very rare congenital deformity in which the anterior bladder wall is absent and the posterior wall of the bladder is exposed externally into the amniotic cavity. This is caused by the incomplete closure of the anterior lower abdominal wall .
There usually other congenital anomalies present such as partial agenesis of the pubic bones, pubic bones diastasis, epispadia, absence of the urethra, clitoris, deformities of the vagina or uterus [1,2,3,4].
Incidence is 0.25-0.5 to 10,000 births, more common in males in the ratio of 2:1.
Both genetic and environmental factors are involved in the etiology. Cloacal membrane covering future bladder fails to retract and persists. This prevents ingrowth of mesenchymal cells which normally form a lower anterior abdominal wall. When cloacal membrane ruptures, the bladder mucosa is not protected by anterior abdominal wall and is exposed directly to the amniotic fluid .
Tong et al. first described the umbilical cord cyst as a clue to prenatal diagnosis of bladder exstrophy . There are have been described cases of bladder exstrophy which present as a cyst in front of the abdomen resembling omphalomesenteric cyst . Cyst eventually disappers and follow-up the ultrasound findings are typical for bladder exstrophy with no visible bladder and a mass protruding from the lower abdomen. Taking into the account the evolution of these cases, it is possible to formulate hypothesis that the natural history of bladder exstrophy begins with a failure of the closure of the lower abdominal wall. The cyst is formed by the cloacal membrane which may be intact until 22 weeks of gestation. Cyst emerges through the abdominal wall and after it ruptures, it's walls evert and the posterior bladder wall forms the soft tissue mass on lower abdominal wall .
In case, the urinary bladder can not be visualized and there is an absence of oligohydramnios or other renal abnormalities, bladder exstrophy should always be considered as a possible diagnosis.
Color Doppler is also a very useful tool in diagnostic of bladder exstrophy. Umbilical arteries normally run along the bladder wall and can be visualized on the transverse scan of the lower abdomen. In case of the bladder exstrophy, umbilical arteries run along the lower anterior abdominal wall mass representing posterior bladder wall.
Absence of bladder
Lower abdominal wall defect with protruding abdominal mass
No sign of oligohydramnios or other gross renal abnormalities
Color Doppler shows umbilical arteries alongside the abdominal wall mass
Lower insertion of the umbilical cord
External genitalia malformation
Umbilical cord cyst in case of intact cloacal membrane
In order not to mistake absent urinary bladder for an empty bladder, we should rescan the lower abdomen after 15 minutes interval. This allows us to see if the bladder was just empty and filled up in a mean time or is still absent. Any case of anuria can cause impaired visualization of the bladder. That’s why is so important to use also color Doppler to identify the course of umbilical arteries and cord insertion. Sagittal views of abdominal wall are the best to demonstrate the lower abdominal wall mass.
We have to differentiate the bladder exstrophy from other anterior abdominal wall defects, such as gastroschisis, omphalocele and cloacal exstrophy.
Gastroschisis has normal bladder and herniated free-floating bowel and normal umbilical cord insertion.
Omphalocele has normal bladder and presents with a midline mass which is more cranial than in bladder exstrophy, umbilical cord inserts onto the omphalocele.
Cloacal exstrophy presents with bowel herniation and is often accompanied by spinal defects and omphalocele (OEIS complex).
“Absent” bladder is a case of non-visualized bladder due to anuria. Bladder is present but is completely empty due to renal anomalies or severe placental insufficiency.
Prenatal counseling with pediatric urologist and delivery in the tertiary center is recommended. Management is primarily surgical, with the aim of the anterior abdominal wall closure within the first 3 days after delivery.
Prognosis is quite favorable. Bladder exstrophy is not associated with an increased risk of pregnancy complication. There can be some late complications resulting form the pelvic floor defects such as urinary incontinence or uterine prolapsed, infertility and increased risk of bladder adenocarcinoma in case the surgical repair was not performed early after delivery .
We report a case of a 28 year old G1P0 who was referred to our hospital for the suspicion of the omphalocele diagnosed during the second trimester ultrasound scan. We scanned the patient at 24 weeks and diagnosed a bladder exstrophy. Apart of the lower abdomen mass, we also saw a anomaly of the genitalia. Patient opted for the pregnancy termination based on the ultrasound examination. Findings of the fetus confirmed our diagnosis.
Images 1,2: Images show a transverse section of the lower abdomen. Note missing lower anterior abdominal wall and urinary bladder; anterior wall mass is indicated by arrow.
Images 3,4: Arrow on the image 3 indicates an abnormal looking genitalia. Image 4 shows the insertion of the umbilical cord.
Images 5,6: Color Doppler on image 5 shows umbilical cord and umbilical arteries which run along the andominal wall mass. 3D image of the both lower extremities and lower abdominal wall.
Video 1: Video shows a lower abdominal mass and umbilical cord insertion located just above the mass.
Images 7,8: Images of the fetus. Note the anterior wall defect, umbilical arteries running along the anterior wall mass as seen on the Color Doppler. Genital anomaly is also present.
Case of a 34-year-old G2 P1 with was referred to our hospital at 18 weeks of gestation due to a cystic tumor located in front of the fetal abdomen. The referral diagnosis was omphalomesenteric cyst. We decided to perform an amniocentesis which resulted in a normal male karyotype. On the follow-up ultrasound exams the tumor disappeared and was replaced by a solid mass consistent with a bladder exstrophy. Intraabdominal cyst diagnosed later on revealed a concomitant intestinal atresia. Patient delivered at 39 weeks of gestation via cesarean section. A newborn male of 3100 grams and Apgar scores 8/10 in 5th/10th minute was transferred to the intermediate care unit. Physical examination confirmed the antenatal diagnosis of bladder exstrophy and anorectal atresia. Neonate underwent surgical closure of bladder exstrophy and colostomy.
Images 1,2: 16 weeks, image 1 shows a sagittal view, note a large cyst in front of the fetal abdomen. Image 2 shows a transverse view of the fetal abdomen and a large anechoic cystic structure.
Images 3,4: Doppler imaging of the umbilical cord. Image 2 shows both umbilical arteries running along the cyst which is a typical finding for a bladder exstrophy.
Images 5,6: 20 weeks, bladder exstrophy has a different appearance, umbilical arteries on image 6 run along the side of an exstrophic bladder.
Images 7,8: Image 7 shows a sagittal view of the abdomen with a bladder exstrophy. Image 8, 24 weeks, transverse view of the bladder exstrophy.
Images 9,10: 24 weeks, Image 9 shows an echogenic structure between the legs. Image 10 shows the umbilical arteries defining the bladder exstrophy.
Images 11,12: Image 11 shows a penis and scrotum. Image 12, 37 weeks, bladder exstrophy.
Images 13,14: 37 weeks, dilated intestine consistent with anorectal atresia.
Images 15,16: Neonate after delivery, note the bladder exstrophy. Image 16 shows perineum with anorectal atresia.
Images 17,18: Neonate after surgical repair of anorectal atresia with colostomy. Image 18 shows a baby at 2 months after a surgical repair of bladder exstrophy.
Image 19: Image of the left shows the fetus with a megacystis (see images 1-4). Image on the right shows the fetus after the bladder rupture (see images 5-6).
This is a case of a 30-year-old G1 P0 with hypothyroidism and severe hyperemesis gravidarum. The transvaginal ultrasound examination at 15 weeks of gestation showed the following findings: absence of the urinary bladder, normal amount of the amniotic fluid and abnormal looking male genitalia. Doppler examination showed a jet of urination from the anterior abdominal wall, next to the penis. Our diagnosis based on the ultrasound examination was a bladder exstrophy with epispadia.
Patient decided for the pregnancy termination just 2 days after our examination. The pathologist confirmed our diagnosis.
Complex anomaly of the urogenital tract and intestinal tract resulting in exstrophy of both bowel and bladder; the most severe form of anomalies in the exstrophy–epispadias complex.
Cloacal exstrophy is a rare congenital anomaly occurring in 0.25-0.5:10,000 births [8,9]. Of the exstrophy-epispadia complex group, bladder exstrophy is the most common form occurring in 0.3:10,0001 births followed by epispadias 0.08-0.25:10,000.
This anomaly results from the failure of two concomitant mesodermal migrations. First, the urorectal septum fails to develop and divide the urogenital sinus from the rectum; second, the mesodermal proliferation forming the infraumbilical abdominal wall and genital tubercle fails to develop. The failure of these two events results in exstrophy of both bladder and intestine.
Review of the embryology of the urinary bladder, genitalia, and rectum is important in understanding the pathogenesis of cloacal exstrophy. The cloacal membrane forms the ventral portion of the cloacal pouch. Two concomitant mesodermal migrations take place near the 5th or 6th week of gestation. Just beneath the umbilicus a mesodermal proliferation extends inferiorly to form the infraumbilical abdominal wall and genital tubercle . This migration repositions the cloacal membrane so that it becomes caudal in location.
A second mesodermal proliferation, the urorectal septum, divides the cloaca into the urogenital sinus anteriorly and the rectum posteriorly. The urorectal septum eventually fuses with the cloacal membrane, dividing it into the urogenital membrane anteriorly and the anal membrane posteriorly.
If the infraumbilical mesoderm fails to develop properly and the cloacal membrane remains ventral in location, bladder exstrophy results as the cloacal membrane resolves. If this occurs before the urorectal septum has divided the urogenital sinus from the rectum, the resultant malformation is cloacal exstrophy. Marshall and Muecke propose that the cloacal membrane acts as a wedge preventing the fusion of the lateral mesoderm [11,12].
In classical cloacal exstrophy there is anomalous exposure of bowel separating two hemibladders. Hindgut and midgut malformations are common. Typically the descending colon ends in a blind pouch and the anus and rectum do not develop. The midgut abnormalities include non-rotation, deficiency of distal ileum, and exposure of bowel through the hemibladders.
It is important to realize that in the exstrophy, the protruding mass does not contain any large cystic areas as it does not contain the urine that is excreted directly from the ureters into the amniotic fluid. The amount of amniotic fluid and upper urinary tracts are normal as there is no obstruction to flow. If a normal bladder cannot be visualized and an anterior mass is found, it is important to examine the cord insertion as this will help in the differential diagnosis between the exstrophies and gastroschisis and omphalocele. Ambiguous genitalia are important findings and visualization of normal external genitalia will probably exclude the diagnosis of bladder or cloacal exstrophy. Color Doppler imaging to correctly identify both umbilical arteries is an important diagnostic tool for localization of the bladder in the lower fetal abdomen [12,13].
Cloacal exstrophy is commonly associated with other anomalies, much more so than bladder exstrophy:
Approximately 70-90% of patients with cloacal exstrophy have an omphalocele. The association of an omphalocele, exstrophy of the cloaca, imperforated anus and spinal abnormalities (meningocele) is referred to as the OEIS complex. Other commonly associated anomalies include cardiovascular, central nervous system, single umbilical artery, vertebral anomalies (46%), upper urinary tract (42%) malrotation (30%), double appendix (30%), absent appendix (21%), short small bowel (19%), small bowel atresia (5%), abdominal musculature deficiency (1%)3. Upper urinary tract anomalies include pelvic kidney, horseshoe kidney, hypoplastic kidney and solitary kidney2. Vertebral malformations include sacralization of L5, congenital scoliosis, sacral agenesis, and interpedicular widening .
The differential diagnosis for cloacal exstrophy includes bladder exstrophy, omphalocele, gastroschisis and occasionally, sacrococcygeal teratoma. Non-visualization of the bladder should help differentiate the exstrophy–epispadias complex from isolated omphalocele or gastroschisis.
The prognosis depends on the presence of associated anomalies. Prior to 1960 cloacal exstrophy was considered to be uniformly fatal. Since then, the mortality has decreased to less than 50%2. A recent reports indicates that 3-4 hours of urinary continence has been achieved in nearly half of one group of patients with repaired cloacal exstrophy. Reproduction in a patient with cloacal exstrophy has not been reported.
Because of the elevated maternal serum alpha-fetoprotein, a large number of these fetuses will be detected by alpha-FP screening. Karyotyping, to exclude aneuploidies, can be offered, although aneuploidies are not typically associated with cloacal exstrophy.
Early sonographic detection and correct diagnosis of the anomaly is important for differential diagnosis and planning of prompt surgical intervention to prevent damage to the exposed organs. When the condition is detected before viability, the condition and its prognosis should be discussed with a team of perinatologist, pediatric surgeons, and genetic counselors. The option of termination can be offered.
Usually, a staged surgical approach is used in management of patients with cloacal exstrophy . Repair of the omphalocele and construction of an ileostomy or colostomy is performed immediately after birth. If ileum and colon are separate, anastomosis of these bowel segments is performed. Sexual assignment is dependent on the adequacy of the phallus, and this decision is typically made early.
In most cases, after a period of observation and nutritional support primary bladder repair or urinary diversion is performed at approximately nine to twelve months. If primary bladder repair is not feasible, urinary diversion to a ileal or colon conduit can be used. There is, however, some encouraging recent experience with early primary closure/reconstruction in the first few days of life.
Reconstruction of genitalia is, otherwise, usually carried out between the ages of 1 to 5 years. In females, duplicated vagina may require excision of the septum. In males the phallus is lengthened using the proximal portion of the corpora. However, most genetic males with cloacal exstrophy do best if the undergo orchiectomy very early in life and are reconstructed as females .
The cloaca, constitutes a functional definitive organ in the pre-mammals like batrachians, reptiles and birds. In humans, it represents a temporary embryonic structure where the genital, urinary and digestive systems join caudally. Its correct development gives origin to the lower abdominal wall, bladder, intestine, anus, genitals and also part of the pelvis bones and lumbosacral spine. Deviation of the normal development of the cloaca causes a series of phenotypes the most severe expression of which is the OEIS complex (Omphalocele-Exstrophy of bladder-Imperforate anus-Spinal deformities) .
This is a rare condition with an incidence of 0.025-0.04:10.000 births.
This condition is believed to result from an arrest of the urorectal septum development in the 7th-8th week of gestation with inhibition of the later differentiation of the cloaca . A single defect in development of infraumbilical mesoderm result in:
1) default of the cloacal partition with common cloacal persistence and imperforate anus
2) rupture of the cloacal membrane with cloacal exstrophy
3) lack of fusion of the genital tubercles and the pubic ramus of the pelvis bones often associated with an omphalocele
4) incomplete development of the lumbosacral vertebras, spina bifida, lipomyelomeningocele or dilated central canal of the spine cord (hydromyelia).
Early prenatal diagnosis is based on the following ultrasound findings :
Associated anomalies include :
- Genital anomalies: ambiguous genitalia, penile agenesis, bifid uterus, clitoris, vaginal duplication
- Fistulas - rectovaginal, rectovesical
- Renal anomalies – horseshoe kidney, renal agenesis
- Limb hypoplasia, aplasia, club feet
- Craniofacial anomalies
- Single umbilical artery
It is very important to differentiate isolated bladder exstrophy from OEIS.
Body stalk anomaly
Amniotic band syndrome
Neural tube defects
Prognosis depends on the structural defects and varies with a severity of this condition. Affected pregnancy is associated with a higher chance of preterm delivery, low birth weight or intrauterine death. Prenatal counseling with multidisciplinary team is recommended. Termination of the pregnancy should be offered as an option. Delivery should be scheduled at a tertiary center.
Multidisciplinary surgical treatment immediately follows the delivery. It usually consists of series of surgeries depending on the severity of the condition.
These are some images and video showing a severe fetal anomaly. The final diagnosis was OEIS (Omphalocele-Exstrophy-Imperforate anus-Spinal defect).
Images 1 and 2: Sagittal and coronal scans showing low abdominal wall defect with a large cystic structure containing debris inside representing dilated bowel.
Image 3: Coronal scan showing large dilated bowel protruding outside the abdominal cavity with debris inside.
Images 4 and 5: Pathological images.
This is a case of a healthy 27-year-old G1 P0 who was presented to our department at 23 weeks of gestation. She had non-contributive family or personal history. She was referred from another center for a suspicion of spina bifida.
Our ultrasound examination revealed the following findings:
Our differential diagnosis included Omphalocele-Exstrophy-Imperforate anus-Spinal defects, OEIS complex. Patient decided for the pregnancy termination. Autopsy examination confirmed our ultrasound findings and described anal atresia as well.
Images 1,2: Image 1 shows an axial view, note the "banana" sign and abnormal appearance of the posterior fossa. Image 2 shows a mass protruding form the abdominal wall, located between the legs of the fetus.
Images 3,4: Image 3 shows insertion of the umbilical cord to the mass, which indicates omphalocele. Image 4 shows the mass between the legs, note the absence of the urinary bladder on all the images.
Images 5,6: Images of the abdominal mass, urinary bladder can not be seen. There is a normal amount of the amniotic fluid.
Images 7: Doppler of the umbilical artery.
Images 8,9: Fetus after pregnancy termination, note the myelomeningocele.
Images 10,11: Omphalocele, bladder exstrophy and anal atresia.
This fetus had an abnormal alpha-fetoprotein. We detected four major findings during our ultrasound exam: omphalocele, neural tube defect, bladder/cloacal exstrophy and clubfeet. Our diagnosis based on the above findings was OEIS complex. The postnatal findings confirmed our diagnosis.
Images 1,2: Image 1 shows omphalocele. Image 2 shows a neural tube defect.
Images 3,4: Image 3 shows a perineal mass, bladder/cloacal exstrophy. Image 4 shows clubfoot.
Images 5: Image 5 shows omphalocele and cloacal exstrophy, prominent, fixed left knee and left club foot.
: Image 6 shows a skin covered neural tube defect.
Pentalogy of Cantrell
Pentalogy of Cantrell is a disorder characterized by :
0.5:10.000 to 0.1:10,000 births .
This defect was reported among the monozygotic twins .
The constellation of defects observed in Pentalogy of Cantrell is thought to result from abnormalities in the differentiation of the intraembryonic mesoderm at approximately 14 to 18 days after conception. The diaphragmatic and pericardial defects result from abnormal development of the septum transversum whereas the sternum and abdominal wall defects are probably related to impaired migration of mesodermal structures .
The association of ectopia cordis and an abdominal wall defect are the most obvious ultrasonographic findings. The diagnosis of the Pentalogy of Cantrell is certain when all five defects are present; is probable when four of them are present (including intracardiac and ventral abdominal abnormalities); and is incomplete when various combination of defects are present, as long as a sternal abnormality is observed [19,22].
- Supraumbilical abdominal wall defects:
Omphalocele or abdominal wall schisis; may contain stomach, liver, bowel or total abdominal contents, evisceration
- Variable displacement of heart and mediastinum due to diaphragmatic and sternal defects
Heart can be completely external or just part of the heart bulging out
- Pleural, pericardial effusion
Ectopia cordis - only protruding heart through the sterna defect, no other associated anomaly
Cleft sternum - heart is bulging but no chest wall defect
Omphalocele – no cardiac or diaphragmatic malformations
Body stalk anomaly – short or absent umbilical cord, severely distorted fetus adhering to the placenta
Amniotic band syndrome – Amniotic bands, limb, head and neck defects
Cardiac anomalies, such as septal defects and Tetralogy of Fallot; craniofacial and vertebral anomalies; chromosomal anomalies, Turner syndrome, trisomy 13,18.
Prognosis is usually fatal. Survival is uncommon and depends on the size of the abdominal wall defect, extent of the cardiac defect, and presence of associated anomalies.
In case neonate survives, series of surgical repairs are the treatment of choice.
These are several images of a fetus with a Pentalogy of Cantrell.
A 26-year-old patient (G1P0) presented at 24th week of pregnancy for routine ultrasound investigation. We found a large ventral wall defect, ectopia cordis, extruded abdominal content through the wall defect, clubfeet, short two-vessel umbilical cord. The findings were consistent with the pentalogy of Cantrell. Here are a few images that we obtained.
Images 1,2: 2D oblique sagittal plane showing ventral thoraco-abdominal wall defect with herniated abdominal organs through the defect and displacement of the heart to the defect (left); and transverse 2D scan showing displaced heart to the thoraco-abdominal defect and herniated abdominal organs (right).
Images 3,4: Color Doppler (left) and power Doppler (right) transverse images showing heart and course of umbilical vein in hernial sac.
Images 5,6: Power Doppler (left) and color Doppler (right) transverse images showing displaced heart to the ventral wall defect.
Images 7,8: Color Doppler images showing short two-vessel umbilical cord.
Images 9,10: 2D images showing clubfoot (left); and deformed spine (right).
A 17-year-old cocaine addicted woman (G1P0) presented at 14th week of pregnancy for a routine ultrasound investigation. A large ventral wall defect with ectopia cordis and eventrated abdominal content was found. The findings were consistent with the pentalogy of Cantrell. Micrognathia and nuchal edema were also present.
Images 1,2: 14th week of pregnancy. Sagittal scans of the fetus with a large abdominal wall defect and ectopia cordis.
Images 3,4: 14th week of pregnancy. Color Doppler transverse images through the fetal abdomen and thorax showing ectopic heart of the fetus and eventrated abdominal content.
Images 5,6: 14th week of pregnancy. Color Doppler image showing ectopic heart of the fetus.
Images 7,8: 14th week of pregnancy. Transverse scan of the fetal head and nuchal region with thickened nuchal translucency.
Images 9,10: 14th week of pregnancy. 3D images of the fetus with ectopic heart.
The following images and video show a case of the pentalogy of Cantrell. The patient was seen for the first time at 29 weeks of her pregnancy. Her previous exams were done abroad and were reported to be normal. Our scan revealed a few anomalies of the fetus including large omphalocele, allantoid cyst of the umbilical cord, polyhydramnios, mild hydrocephalus, and meningomyelocele. The pregnancy was terminated by a cesarean section at 35 weeks of pregnancy because of marked polyhydramnios. The newborn died shortly after delivery and the postnatal examination additionally discovered defect of the lower sternum, anterior diaphragm and diaphragmatic pericardium. The diagnosis of the pentalogy of Cantrell was postulated.
Images 1, 2: The images show the omphalocele of the fetus and polyhydramnios.
Images 3,4: The image 3 shows mild hydrocephalus of the fetus. The image 4 show the allantoid cyst of the umbilical cord.
: The video shows the large omphalocele the fetus which turned out to be a part of the pentalogy of Cantrell.
A 28-year-old patient (G3P1) presented at 33 weeks of gestation for the first ultrasound scan during this current pregnancy. We have seen ectopia cordis, large omphalocele with herniated liver. The diagnosis based on the the ultrasound findings was Pentalogy of Cantrell. Patient delivered via cesarean section at 35 weeks of gestation. The baby died after delivery.
Images 1,2: Image1 shows a coronal view of the fetus, there is an ectopic heart (note arrow) and herniated liver below it. Image 2 shows the ectopic heart and herniated liver.
Images 3,4: Images show a herniated liver and heart.
Images 5,6: Image 5 shows a transverse view of the abdomen at the leval of stomach, note the anterior wall defect indicated by arrow. Image 6 shows omphalocele.
Images 7,8: Images show fetal heart located outside of the thoracic cavity.
Images 9,10: 3D-images with the anterior wall defect.
Video 1,2,3: Videos showing anterior wall defect with ectopic heart and omphalocele.
Image 11: Image of the neonate after delivery.
Video 4: Neonate after delivery.
This is a case of monochorionic diamniotic twin pregnancy in a primigravida who was scanned at our department at 13 weeks of gestation.
We did not detect any abnormality at first twin, except of the reverse flow in ductus venosus.
The second twin was affected, the ultrasound examination revealed following findings:
a) Large omphalocele with herniating bowel and stomach, covered by membrane.
b) Ectopia cordis, bradycardia
c) Diaphragmatic hernia
d) Defect of the inferior sternum
- Alobar holoprosencephaly with orbital hypotelorism and proboscis
- Cystic hygroma
Images 1,2: Image 1 shows the sagittal view of the "normal" twin, NT=1.0 mm. Image 2 shows Doppler flow of the ductus venosus, note the reverse flow of the ductus venosus.
Images 3,4: Affected twin, image 3 shows frontal view of the fetal face, note hypotelorism, arrows point at the eyes. You can see omphalocele and ectopic heart (*). Image 4 shows transverse view of the thorax with abdominal wall defect and omphalocele.
Images 5,6: Axial view of the fetal head with monoventricle, fused thalami, proboscis and cystic hygroma.
Images 7,8: Image 7 shows bradycardia of the affected twin. Image 8 shows 3-D image of the twins, affected twin is on the right, you can see abdominal wall with large omphalocele.
Videos 1,2: Video 1 shows the omphalocele and ectopic heart with bradycardia. Video 2 shows 3-D images of both twins.
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