Congenital high airway obstruction syndrome: MR/US findings, effect on management, and outcome

BACKGROUND

Congenital high airway obstruction syndrome (CHAOS) is a rare disorder defined as any fetal abnormality that obstructs the larynx or trachea. Prompt airway intervention at delivery after accurate prenatal diagnosis may allow survival of this otherwise fatal condition.

OBJECTIVE

To identify prenatal MRI findings in CHAOS, to compare these findings with those of fetal US, to determine if imaging alters diagnosis and management decisions, and to correlate prenatal with postnatal imaging findings.

MATERIALS AND METHODS

Records and MRI scans of ten fetuses with CHAOS were reviewed, and the findings correlated with outside and same-day fetal US and postnatal imaging findings. Fetal lung volumes were measured on MRI scans.

RESULTS

Large lung volumes were found in 90% of the fetuses. Increased lung signal intensity, inverted diaphragm, and a dilated, fluid-filled lower airway were identified in all. The obstruction level was identified in 90%. MRI changed screening US diagnosis in 70%, but was concordant with the tertiary care US imaging in 90%. Seven fetuses were terminated or died in utero, and three fetuses survived after ex utero intrapartum tracheostomy placement. Autopsy or bronchoscopy performed in 60% confirmed CHAOS. Postnatal chest radiographs and CT showed hyperinflation, while US and fluoroscopy showed diminished diaphragmatic motion.

CONCLUSION

MRI demonstrates large lung volumes, increased lung signal intensity, inverted diaphragm, and dilated fluid-filled lower airway, and usually identifies the obstruction level. The degree of correlation between MRI and tertiary prenatal US is high, but CHAOS is frequently misdiagnosed on screening US. Correct diagnosis may enable planned airway management. Voluminous lungs and diaphragmatic abnormalities persist on postnatal imaging.

Fetal tracheal occlusion for severe congenital diaphragmatic hernia in humans: a morphometric study of lung parenchyma and muscularization of pulmonary arterioles

OBJECTIVE

The aim of this study is to examine structure of lung parenchyma (Pp) and muscularization of pulmonary arterioles (PAs) in human fetuses that underwent tracheal occlusion (TO) therapy for severe congenital diaphragmatic hernia (CDH).

MATERIAL

Fifteen fetuses underwent TO, with 5 survivors (Am J Obstet Gynecol. 2000:183;1059-1066). Paraffin-embedded lung specimens from 7 of 10 nonsurvivors (CDH-TO) and 6 age-matched fetuses (CDH) were available for morphometric analysis, which included measurements of point fraction of lung Pp and surface density. The PAs were categorized according to external diameter (<70 microm and 70 <or= 140 microm). Percent medial wall thickness (%MWT) was calculated by dividing raw measurements of MWT by external diameter.

RESULTS

Gestational age at TO was 27.6 +/- 0.9 weeks with a mean duration of TO of 32.6 +/- 6.8 days. Gestational age at delivery (CDH-TO 31.9 +/- 0.9 vs CDH 35.4 +/- 1.8 weeks; P = .18) and postnatal survival time (CDH-TO 20.5 +/- 6.0 vs CDH 18.6 +/- 7.8 days; P = .85) were not significantly different between groups. Tracheal occlusion significantly increased the lung-to-body weight ratio (CDH-TO 13.0 +/- 2.2 vs CDH 6.6 +/- 0.9; P = .02). Tracheal occlusion tended to decrease right-lung Pp (CDH-TO 54.6% +/- 2.6% vs CDH 65.7% +/- 5.9%; P = .05), whereas left-lung Pp was not different between groups (CDH-TO 63.0% +/- 3.5% vs CDH 66.7% +/- 4.1%; P = .51). Surface density of airspaces was not different between groups in either left (CDH-TO 171.3 +/- 16.1 cm(-1) vs CDH 151.1 +/- 8.1 cm(-1); P = .34) or right (CDH-TO 172.0 +/- 10.6 cm(-1) vs CDH 160.8 +/- 3.6 cm(-1); P = .33) lungs. The %MWT in small and large PA was similar between groups.

CONCLUSIONS

Open prenatal TO in human fetuses increased lung growth, as evidenced by an increase in lung weight, but did not improve parenchymal structure or muscularization of PAs.

Fetal spina bifida repair--current trends and prospects of intrauterine neurosurgery

Myelomeningocele is a common dysraphic defect leading to severe impairment throughout the patient's lifetime. Although surgical closure of this anomaly is usually performed in the early postnatal period, an estimated 330 cases of intrauterine repair have been performed in a few specialized centers worldwide. It was hoped prenatal intervention would improve the prognosis of affected patients, and preliminary findings suggest a reduced incidence of shunt-dependent hydrocephalus, as well as an improvement in hindbrain herniation. However, the expectations for improved neurological outcome have not been fulfilled and not all patients benefit from fetal surgery in the same way. Therefore, a multicenter randomized controlled trial was initiated in the USA to compare intrauterine with conventional postnatal care, in order to establish the procedure-related benefits and risks. The primary study endpoints include the need for shunt at 1 year of age, and fetal and infant mortality. No data from the trial will be published before the final analysis has been completed in 2008, and until then, the number of centers offering intrauterine MMC repair in the USA is limited to 3 in order to prevent the uncontrolled proliferation of new centers offering this procedure. In future, refined, risk-reduced surgical techniques and new treatment options for preterm labor and preterm rupture of the membranes are likely to reduce associated maternal and fetal risks and improve outcome, but further research will be needed.

Prenatal ultrasonographic gastrointestinal abnormalities in fetuses with gastroschisis do not correlate with postnatal outcomes

PURPOSE

In the setting of gastroschisis, the clinical significance of prenatal ultrasound findings of secondary changes in bowel appearance remains unknown. The purpose of this study was to correlate prenatal identification of additional gastrointestinal sonographic abnormalities with postnatal clinical outcome.

METHODS

A retrospective review was conducted on 64 fetuses with a prenatal diagnosis of gastroschisis treated at the Children's Hospital of Philadelphia from 2000 to 2007. Postnatal outcomes were compared between newborns with additional sonographic gastrointestinal abnormalities and those without secondary changes to the bowel appearance.

RESULTS

Thirty (47%) patients had at least one gastrointestinal abnormality (eg, bowel dilatation, echogenic bowel, thickened bowel, matted bowel, herniation of the stomach through the abdominal wall defect, or segmental loss of bowel peristalsis) on prenatal ultrasound. There were no significant differences between groups with respect to the time to initial and full enteral nutrition, total hospital stay, requirement for ventilator support, central line infection rates, reoperation rates, or mortality.

CONCLUSIONS

In the setting of gastroschisis, isolated findings of gastrointestinal abnormalities on prenatal ultrasound do not correlate with adverse postnatal outcome.

Outcomes after postnatal resection of prenatally diagnosed asymptomatic cystic lung lesions

BACKGROUND

Symptomatic congenital lung lesions require surgical resection, but the management of asymptomatic lung lesions is controversial. Some surgeons advocate observation because of concerns about potential operative morbidity and mortality, as well as a lack of long-term follow-up information. On the other hand, malignant degeneration, pneumonia, and pneumothorax are known consequences of cystic lung lesions. This study aims to assess the safety of resection for asymptomatic lung lesions that were diagnosed before birth.

METHODS

A retrospective review of all patients with prenatally diagnosed lung lesions at Children's Hospital of Philadelphia (Philadelphia, Penn) was performed from 1996 to 2005. The perioperative course of patients who were asymptomatic was analyzed.

RESULTS

One hundred five complete records of children with asymptomatic lesions were reviewed. Overall mortality was 0% and morbidity was 6.7% including 2.9% significant postoperative air leak and 3.8% transfusion requirement. Nine patients had a pathologic diagnosis that differed from preoperative radiological findings, and 9 patients had additional pathologic findings.

CONCLUSION

This series demonstrates that surgery can be performed safely on patients who were asymptomatic with congenital cystic adenomatoid malformation of the lung and other types of lung lesions with no mortality and minimal morbidity. The frequency of disparate pathologic diagnoses and the potential for development of malignancy and other complications support the argument for early resection.

Accuracy of [18F]fluorodopa positron emission tomography for diagnosing and localizing focal congenital hyperinsulinism

OBJECTIVES

Focal lesions in infants with congenital hyperinsulinism (HI) represent areas of adenomatosis that express a paternally derived ATP-sensitive potassium channel mutation due to embryonic loss of heterozygosity for the maternal 11p region. This study evaluated the accuracy of 18F-fluoro-l-dihydroxyphenylalanine ([18F]DOPA) positron emission tomography (PET) scans in diagnosing focal vs. diffuse disease and identifying the location of focal lesions.

DESIGN

A total of 50 infants with HI unresponsive to medical therapy were studied. Patients were injected iv with [18F]DOPA, and PET scans were obtained for 50-60 min. Images were coregistered with abdominal computed tomography scans. PET scan interpretations were compared with histological diagnoses.

RESULTS

The diagnosis of focal or diffuse HI was correct in 44 of the 50 cases (88%). [18F]DOPA PET identified focal areas of high uptake of radiopharmaceutical in 18 of 24 patients with focal disease. The locations of these lesions matched the areas of increased [18F]DOPA uptake on the PET scans in all of the cases. PET scan correctly located five lesions that could not be visualized at surgery. The positive predictive value of [18F]DOPA in diagnosing focal adenomatosis was 100%, and the negative predictive value was 81%.

CONCLUSIONS

[18F]DOPA PET scans correctly diagnosed 75% of focal cases and were 100% accurate in identifying the location of the lesion. These results suggest that [18F]DOPA PET imaging provides a useful guide to surgical resection of focal adenomatosis and should be considered as a guide to surgery in all infants with congenital HI who have medically uncontrollable disease.

Antenatal diagnosis and management of congenital cystic adenomatoid malformation

One of the most enigmatic pulmonary lesions encountered in the prenatal period is the congenital cystic adenomatoid malformation (CCAM). This review presence current thinking on pathogenesis, prenatal assessment, fetal intervention, and management for this pulmonary malformation. Careful delivery planning by utilizing a multidisciplinary approach will optimize neonatal outcomes.

Pregnancy outcomes following bipolar umbilical cord cauterization for selective termination in complicated monochorionic multiple gestations

OBJECTIVE

To review pregnancy and childhood outcomes following selective termination by ultrasound guided bipolar umbilical cord cauterization (UCC) in complicated monochorionic multifetal pregnancies.

STUDY DESIGN

Consenting patients (27 of 49, 55%) had review of pregnancy history and pediatric development in the surviving twin following selective UCC.

RESULTS

UCC was performed at 21.2 +/- 2.8 weeks gestational age, followed by a liveborn delivery (n = 28) at 34.4 +/- 4.7 weeks. Mean birth weight was 2,218 +/- 926 g. Complications included preterm labor (25.0%), premature rupture of membranes (17.8%), placental abruption (10.7%) and chorioamnionitis (7.1%). Perinatal mortality was 10.3% in continuing fetuses. However, 96.2% of pregnancies achieved livebirths with 96% of neonates showing apparently normal development between ages 1.5 and 5 years.

CONCLUSION

Bipolar UCC is a reasonably safe and effective treatment for selective termination in complicated monochorionic pregnancies.

Morphologic analysis of the neuromuscular development of the anorectal unit in fetal rats with retinoic acid induced myelomeningocele

To investigate whether myelomeningocele (MMC) is associated with a global neuromuscular maldevelopment of the lower gastrointestinal (GI) tract and anorectum, the distribution and staining intensity of non-neuronal (alpha-smooth-muscle-actin), neural crest cell (NCC, [Hoxb5]), and neuronal markers (PGP-9.5, synaptophysin, neurotubulin-beta-III) within the distal colon, rectum, and anal sphincters were analyzed by immunohistochemistry and Western blot in rat fetuses with retinoic acid (RA) induced MMC. At term (E22), no gross-morphological differences of the anorectal unit of OIL (n=21) MMC (n=31), and RA-exposed-non MMC (RA, n=19) fetuses were found. Smooth muscle cells were evenly distributed within the muscle layers of the rectum and the internal anal sphincter in OIL, MMC, and RA fetuses. Density and staining intensity of NCC and mature enteric neurons within the myenteric plexus of the distal colon and rectum and innervation pattern within anal sphincters in MMC fetuses were analogous to RA and OIL controls. Normal smooth muscle and myenteric plexus development of the rectum and normal innervation of the anal sphincters and pelvic floor suggests that MMC is not associated with a global neuromuscular maldevelopment of lower GI structures in this short-gestational model.

Liver position and lung-to-head ratio for prediction of extracorporeal membrane oxygenation and survival in isolated left congenital diaphragmatic hernia

OBJECTIVE

The purpose of this study was to determine the ability of liver position and lung-to-head ratio to predict outcome in isolated left congenital diaphragmatic hernia.

STUDY DESIGN

We reviewed prenatal studies and postnatal outcomes of congenital diaphragmatic hernia between January 1996 and January 2006.

RESULTS

Eighty-nine patients received prenatal and postnatal care at 1 institution. In fetuses with liver up, extracorporeal membrane oxygenation was required in 39 of 49 fetuses (80%), compared with 10 of 40 fetuses (25%) for those with liver down (P < .0001). Overall survival rate was 45%, compared with 93% for those with liver down (P < .00005). Low lung-to-head ratio (<1.0) predicted increased incidence of extracorporeal membrane oxygenation (75%; P = .036) and lower survival (35%; P = .0003). However, when measured at <24 weeks of gestation, lung-to-head ratio was not predictive of outcome (extracorporeal membrane oxygenation, P = .108; survival, P = .150); liver position remained highly predictive (extracorporeal membrane oxygenation, P = .006; survival, P = .001).

CONCLUSION

Liver position is the best prenatal predictor of outcome in isolated left congenital diaphragmatic hernia. Lung-to-head ratio alone should not be used to counsel families regarding mid gestational management choices.

Postnatal Chest Wall Deformities after Fetal Thoracoamniotic Shunting for Congenital Cystic Adenomatoid Malformation

OBJECTIVES

Large macrocystic congenital cystic adenomatoid malformations (CCAMs) can be treated with thoracoamniotic (TA) shunting to reduce CCAM volume. Two CCAM fetuses treated with TA shunt had postnatal radiographic rib deformities.

STUDY DESIGN

Retrospective review of prenatal TA shunting for large macrocystic CCAMs evaluated for the presence of rib deformities. Comparison groups not eligible for TA shunting included nonshunted CCAMs resected postnatally (group A) and size-matched nonshunted CCAMs resected postnatally (group B).

RESULTS

Chest wall abnormalities were identified in 77% of newborns ranging from severe concavity and fractures (in two fetuses shunted at 18 and 20 weeks of gestation) to rib thinning compared to comparison groups A and B. The severity of chest wall deformity correlated with earlier gestational age at shunting.

CONCLUSIONS

TA shunting at less than 21 weeks of gestational age may result in postnatal chest wall deformity. This observation should be discussed during counseling for this procedure.

Prenatal diagnosis of partial trisomy 1q and monosomy X in a fetus with a congenital lung lesion and hydrops fetalis

We report on the prenatal diagnosis of partial trisomy 1q and monosomy X in a fetus with a congenital lung lesion and hydrops. The finding of hydrops in a fetus with a small lung lesion, congenital cystic adenomatoid malformation (CCAM) volume to head circumference ratio (CVR) 0.78, prompted cytogenetic analysis of amniotic fluid, revealing an unbalanced translocation between chromosomes X and 1 [46,X,der(X)t(X;1)(p11.2;q25 or q31)]. The incidence of chromosomal abnormalities with CCAM lesions is estimated at 1.6%. This is the first reported case of prenatally diagnosed partial trisomy 1q and monosomy X presenting as a fetal lung lesion and hydrops.

Effect of Maternal Betamethasone Administration on Prenatal Congenital Cystic Adenomatoid Malformation Growth and Fetal Survival

OBJECTIVE

To evaluate the effect of prenatal steroid treatment on the growth of congenital cystic adenomatoid malformations (CCAM) and survival in affected fetuses not amenable to other percutaneous ultrasound-guided prenatal interventions.

METHODS

A retrospective review of patients with a CCAM or hybrid lesion treated with two maternal prenatal betamethasone injections was performed. Patients receiving cyst aspiration or thoracoamniotic shunting at the time of or after steroid administration were excluded. Growth rates and survival data were compared to historical non-steroid treated controls.

RESULTS

Eleven patients were treated with prenatal steroids (10 microcystic and 1 macrocystic). Survival was 100% in fetuses with hydrops (5/5) or a CCAM volume ratio (CVR) >1.6 (7/7) at the time of steroid administration. This compares to a mortality of 100 and 56.2% respectively in historical non-treated controls. Resolution of hydrops was seen in 80% (4/5) of steroid-treated patients. CCAM growth rates were variable after steroid administration. However, when compared to historical data where CVR and CCAM volume have been documented to increase until 28 weeks' gestation, the CVR and CCAM volume growth rates decreased in 72.73% and 50% of patients respectively from the time of steroid administration to 28 weeks' gestation.

CONCLUSIONS

In the fetus with a CCAM, the presence of hydrops fetalis or a CVR >1.6 is indicative of poor fetal outcome without prenatal intervention. The observed effect of antenatal steroid treatment on CCAM growth is variable, but its potential to improve survival in these high-risk groups is encouraging and warrants further controlled evaluations.

Does a Myelomeningocele Sac Compared to No Sac Result in Decreased Postnatal Leg Function following Maternal Fetal Surgery for Spina Bifida Aperta?

OBJECTIVE

A fetus with large sac S1 myelomeningocele (MMC) but bilateral talipes prompted the question, 'Does the presence or size of an MMC sac affect postnatal leg function?'

STUDY DESIGN

An MMC database with prenatal, birth, and a minimum of 1-year follow-up evaluation was reviewed. All fetuses had in-utero MMC repair at 20 + 0 to 25 + 6 weeks at a single institution. Fifty-four fetuses had prenatal evaluation, with 48 children completing a birth and a 1-year evaluation of leg function.

RESULTS

An MMC sac was present in 38/54 (70%) of fetuses evaluated in-utero and had been present in 35/48 (73%) of children evaluated at 1 year of age. Although leg function evaluated at 1 year was better than expected in the 'no sac' group (p = 0.059), this did not reach statistical significance.

CONCLUSION

The presence of an MMC sac may increase postnatal lower limb morbidity.

Gastroschisis: Growth Patterns and a Proposed Prenatal Surveillance Protocol

OBJECTIVE

To assess intrauterine growth for fetuses with gastroschisis using retrospective serial ultrasound assessment from fetuses diagnosed prenatally with gastroschisis. The growth assessment could be available as a prospective tool to direct an antepartum fetal surveillance protocol.

METHODS

This is a retrospective review of all cases of gastroschisis evaluated prenatally at a single institution between February 1996 and March 2002. Charts were reviewed for serial ultrasound assessment, gestational age at delivery, mode of delivery, and birth weight. Growth assessment was determined for abdominal circumference, biparietal diameter, head circumference, femur length, and estimated fetal weight (IRB No. 2002-1-2648).

RESULTS

Forty patients had delivered by March 2002. One hundred and two ultrasound reports were reviewed. Gastroschisis growth curves showed that the 50th percentile was shifted to the right when compared to normal growth curves for abdominal circumference, biparietal diameter, head circumference, and femur length. The average birth weight was 2,359 g. Compared with a standard population, 44% (16/36) were below the 5th percentile, 61% (22/36) were below the 10th percentile, and 95% (34/36) were below the 50th percentile for gestational age. The average gestational age at delivery was 36.3 weeks. Mothers were nulliparous in 78%, with a mean age of 21.3 years.

CONCLUSIONS

(1) Fetuses with gastroschisis show a symmetric intrauterine growth restriction pattern consistent with early development of growth delay; (2) the 50th percentile biometry measurements for the gastroschisis population are shifted to the right on normal fetal growth curves; (3) the birth weight is at or below the 10th percentile in 61% of the newborns with gastroschisis, and (4) an antepartum surveillance protocol is proposed based on growth patterns of fetuses with gastroschisis.

Diagnosis and localization of focal congenital hyperinsulinism by 18F-fluorodopa PET scan

OBJECTIVES

To assess the accuracy of 18F-fluoro-L-dihydroxyphenylalanine ([18F]-DOPA) PET scans to diagnose focal versus diffuse disease and to localize focal lesions in infants with congenital hyperinsulinism.

STUDY DESIGN

Twenty-four infants with hyperinsulinism unresponsive to medical therapy were studied. Patients were injected intravenously with [18F]-DOPA, and PET scans were obtained for 1 hour. Images were coregistered with abdominal CT scans.

RESULTS

The diagnosis of focal or diffuse hyperinsulinism was correct in 23 of the 24 cases (96%) and equivocal in 1 case. [18F]-DOPA PET identified focal areas of high uptake of radiopharmaceutical in 11 patients. Pathology results confirmed that all 11 had focal adenomatosis, and the locations of these lesions matched the areas of increased [18F]-DOPA uptake on the PET scans in all of the cases.

CONCLUSIONS

[18F]-DOPA PET scans were 96% accurate in diagnosing focal or diffuse disease and 100% accurate in localizing the focal lesion. These results suggest that [18F]-DOPA PET imaging should be considered in all infants with congenital hyperinsulinism who need to have pancreatectomy.

Structural and functional characterization of bladder smooth muscle in fetal rats with retinoic acid-induced myelomeningocele

Myelomeningocele (MMC) is the most common cause of neurogenic bladder dysfunction (NBD). We recently developed a novel retinoic acid (RA)-induced MMC model in fetal rats. The objective of this study was to use this model to assess functional and structural characteristics of the detrusor muscle in MMC-associated NBD. Time-dated pregnant Sprague-Dawley rats were gavage fed 60 mg/kg RA dissolved in olive oil or olive oil alone [embryonic day 10 ( E10)]. Bladder specimens from olive oil-exposed fetuses (OIL; n = 71), MMC ( n = 79), and RA-exposed-no MMC (RA, n = 62) were randomly assigned for functional and histopathological evaluation and protein analysis. Contractility responses to field and agonist-mediated stimulation (KCl and bethanecol) were analyzed. The expression patterns of α-smooth muscle actin, myosin, desmin, vimentin, and collagen III and I were analyzed by immunohistochemistry and Western blotting. Spatial and temporal distribution of nerve fibers within the detrusor muscle was monitored by neurotubulin-β-III throughout gestation. Neither OIL, MMC, nor RA detrusor responded to field stimulation. MMC bladder strips showed a significant decrease in contractility after KCl and bethanechol stimulation compared with OIL and RA bladders. Bladder detrusor morphology and expression patterns of smooth muscle markers were similar between groups. Detrusor muscles in OIL and RA fetuses were densely innervated, possessing abundant intramural ganglia and nerve trunks that branch to supply smooth muscle bundles. In MMC bladders, neurotubulin-β-III-positive nerve fibers were markedly decreased with advancing gestational age and were almost completely absent at term ( E22). We conclude that the biomechanical properties of fetal rat MMC bladders are analogous to that seen in humans with MMC-associated NBD. Decreased nerve density indicates loss of peripheral neural innervation throughout gestation. The early observation of decreased innervation and decreased contractility in the absence of morphologic abnormalities in muscle structure or extracellular matrix supports a pathophysiological hypothesis that denervation is the primary insult preceding the observed alterations in bladder muscle structure and function.

Gallstone ileus 20 years after a Kasai procedure using a stapled antireflux valve

We present a case of intestinal obstruction owing to a gallstone ileus in a patient 20 years after a Kasai procedure for biliary atresia in which a stapled antireflux valve was constructed to treat recurrent cholangitis. The etiology of this rare presentation is discussed.

Multiple ectopic lesions of focal islet adenomatosis identified by positron emission tomography scan in an infant with congenital hyperinsulinism

Congenital hyperinsulinism (HI) exists in 2 histologic forms, focal and diffuse, and rarely has been attributed to lesions in ectopic pancreatic tissue. The ability to distinguish focal from diffuse HI and locate focal lesions has been difficult, thus limiting the optimal management of HI. We present a case of HI resulting from focal pancreatic and ectopic pancreatic lesions. After a near-total pancreatectomy failed to improve the patient's condition, a positron emission tomography (PET) scan performed with 18F-fluoro-L-dihydroxyphenylalanine demonstrated a focal lesion remaining in the head of the pancreas as well as 4 hot spots inferior to the remaining pancreas. Surgical exploration found pancreatic rests in the jejunum responsible for the hot spots seen on PET. Resection of the remainder of the pancreas as well as the small intestinal lesions resulted in correction of the patient's HI. Pathology confirmed the presence of focal HI lesions in the pancreatic head and small intestinal specimens. This case supports the ability of ectopic pancreatic tissue to contribute to the pathology of HI. It highlights the ability of PET to successfully identify focal lesions, including ectopic tissue, responsible for hyperinsulinemic hypoglycemia.

Prenatal glucocorticoids improve lung morphology and partially restores surfactant mRNA expression in lambs with diaphragmatic hernia undergoing fetal tracheal occlusion

In fetal sheep with surgically created diaphragmatic hernia (DH), tracheal occlusion (TO) can restore lung growth but does not ameliorate the increase in inter-alveolar wall thickness (T(W)). We determined whether prenatal exposure to glucocorticoids (GC) could reduce T(w) in fetuses with DH undergoing TO. At 65 days of gestation, DH was created in 12 fetal sheep, and TO subsequently performed at 110 days (DH/TO). Six of these fetuses were exposed to betamethasone (DH/TO + GC; 0.5 mg/kg; maternal, IM) 48 hr before delivery; Sham operated fetuses (n = 7) served as controls. At 139 days, we measured alveolar surface density (S(V)), parenchymal tissue fraction, T(W), alveolar type 2 (AE2) cell density and lung surfactant protein (SP) mRNA expression. Prenatal GC decreased T(W) and S(V) by 33% and 27% respectively, and increased fixed lung volume (by 55%), AE2 cell density and partially restored SPmRNA expression. Our data indicate that prenatal exposure to GC can reverse some of the negative effects of prolonged fetal TO. We hypothesize that a GC-induced reduction in lung liquid volume during TO contributes, in part, to the observed increase in AE2 cell density and SPmRNA expression.

Prenatal Diagnosis and Postnatal Management of Diffuse Congenital Hyperinsulinism: A Case Report

We present the first case of the prenatal diagnosis of congenital hyperinsulinism based on the genetic analysis of known family mutations in the SUR1 gene. An amniocentesis was performed at 16 weeks gestation at which time two mutations in the SUR1 gene were identified consistent with the diagnosis of diffuse hyperinsulinism. The mother was transported to our facility and underwent an elective caesarian section at 38 weeks gestation. The diagnosis was confirmed and treatment was initiated within the first minutes of life. After a short course of failed medical management, the patient underwent a 98% pancreatectomy with subsequent good glycemic control. This case highlights the benefits of the timely in utero diagnosis of hyperinsulinism by mutational analysis.

Diagnosis and characterization of fetal sacrococcygeal teratoma with prenatal MRI

OBJECTIVE

The purpose of this study was to determine whether prenatal MRI provides additional information about fetal sacrococcygeal teratoma compared with prenatal sonography.

MATERIALS AND METHODS

Twenty-two pregnant women with fetal sacrococcygeal teratoma underwent prenatal MRI (mean gestational age, 23 weeks). The size, location, mass characteristics, and compressive effects of the tumors were determined and correlated with sonography and postnatal findings.

RESULTS

Based on the MRI findings, the following American Academy of Pediatrics, Surgical Section classifications were assigned: type I in six patients, type II in 12, and type III in four. No type IV tumors were found. The sacrococcygeal teratoma appeared entirely cystic in five fetuses, microcystic in one, mixed cystic and solid in 12, and solid in four. The diagnosis of sacrococcygeal teratoma was accurate in all cases assessed at our center using both MRI and sonography. Two additional patients initially referred with the diagnosis of sacrococcygeal teratoma had a different diagnosis at reevaluation at our institution (healthy, n = 1; myelomeningocele, n = 1). MRI was superior to sonography for detecting displacement of the colon (n = 11), urinary tract dilatation (n = 9), hip dislocation (n = 4), intraspinal extension (n = 2), and vaginal dilation (n = 1). In fetuses with sacrococcygeal teratoma types II and III, MRI better showed the cephalic extent of the tumor compared with sonography. MRI findings were confirmed at surgery or autopsy in all patients. Three fetuses with high output cardiac physiology underwent open fetal resection of the tumor at 21-, 24-, and 26-weeks' gestational age with two surviving.

CONCLUSION

Our results show that ultrafast fetal MRI is a useful adjunct to the prenatal evaluation of fetal sacrococcygeal teratoma. Compared with sonography, MRI more accurately characterized the intrapelvic and abdominal extent of the tumors and provided more information on compression of adjacent organs. The additional anatomic resolution provided by MRI resulted in more accurate prenatal counseling and improved preoperative planning for surgical resection.

Fetal Head Biometry Assessed by Fetal Magnetic Resonance Imaging following in utero Myelomeningocele Repair

OBJECTIVE

To examine the impact of fetal myelomeningocele (MMC) repair on fetal head biometry and cerebrospinal fluid (CSF) spaces assessed by magnetic resonance imaging (MR) studies.

STUDY DESIGN

Axial measurements of intracranial structures were taken at defined anatomical landmarks. Pre- and postnatal head biometry data and CSF spaces obtained from in utero repaired MMC fetuses (n = 22) were compared to the pre- and postnatal measurements of MMC patients that underwent standard neurosurgical MMC repair after birth (n = 16) and a cohort of age-matched control patients (prenatal, n = 52; postnatal, n = 9).

RESULTS

In fetuses with MMC, initial MR scans showed an almost complete absence of supratentorial and posterior fossa CSF spaces. No differences in postnatal CSF spaces were found between controls and prenatally repaired MMC newborns. In fetuses with postnatal MMC repair, CSF spaces remained significantly reduced (p < 0.0001). The mean ventricular diameter (VD) increase in the postnatal repaired MMC group was significantly higher compared to the mean percentage of VD increase in the fetal repaired MMC group (6.4 vs. 4.2 mm; p = 0.02). Pre- and postnatal brain thickness measurements were significantly reduced in both MMC populations compared to age-matched normal values (p < 0.0001). In contrast to postnatally repaired patients, in utero repair fetuses showed significant reversal of hindbrain herniation and normalization of the posterior fossa CSF spaces.

CONCLUSION

Mid-gestational repair of MMC promotes normalization of extra-axial CSF spaces. Due to progressive ventriculomegaly, brain thickness remains decreased in both prenatal repaired and age-matched non-repaired MMC patients when compared to age-matched normal values. Restoration of CSF volume in the posterior fossa after in utero repair is indicative of reversal of hindbrain herniation.

Prenatal glucocorticoids and exogenous surfactant therapy improve respiratory function in lambs with severe diaphragmatic hernia following fetal tracheal occlusion

Fetal tracheal occlusion (TO) accelerates lung growth and can reverse severe lung hypoplasia associated with diaphragmatic hernia (DH), however, lung compliance (Cl) and respiratory gas exchange remain abnormal. We determined the individual and combined effects of prenatal glucocorticoids (GC) and exogenous surfactant therapy (S) on postnatal pulmonary function in lambs with DH that underwent prolonged TO. DH was created in 22 fetal sheep at 65 d of gestation and TO performed at 110 d. Eleven DH/TO animals received prenatal GC (betamethasone, 0.5 mg/kg) 48 h before delivery; six GC-treated and five non-GC lambs were administered surfactant (Infasurf, 3 mg/kg) at birth. Six sham-operated lambs served as controls. Lambs were delivered at 139 d gestation and ventilated for 2 h. GC or surfactant therapy alone significantly improved respiratory gas exchange, Cl, and ventilatory efficiency index. Total lung capacity was normalized only in DH/TO lambs that received both GC and S.

The diagnosis of ectopic focal hyperinsulinism of infancy with [18F]-dopa positron emission tomography

BACKGROUND

Congenital hyperinsulinism (CHI) is a cause of severe hypoglycemia in the neonatal and infancy period. Histologically, there are two subtypes with diffuse and focal disease. The preoperative differentiation of these two forms is very important because the surgical management is radically different. The focal form of the disease can be cured if the focal lesion can be localized accurately and completely resected with surgery.

AIM

We report the case of a child who underwent three pancreatectomies with a choledochoduodenostomy and a cholecystectomy but continued to have severe hyperinsulinemic hypoglycemia.

METHODS/RESULTS

Radiological investigations including imaging with (18)fluoro-L-Dopa positron emission tomography scan showed a clear focus of increased (18)F-fluoro-L-Dopa uptake in the vicinity of the former head of the pancreas. On the magnetic resonance imaging scan, this focal uptake appeared to localize adjacent or next to duodenum (in the wall or cavity of the duodenum).

CONCLUSIONS

This unique case highlights the importance of correctly localizing and completely resecting the focal lesion in patients with CHI. (18)Fluoro-L-Dopa positron emission tomography scan can identify ectopic focal lesions in patients with CHI.

Fetal Pulmonary Malformations: Defining Histopathology

Although classification schemes have sought to categorize congenital cystic lung malformations, studies including the pathology of pulmonary malformations occurring specifically during the fetal period are limited. To better characterize such histopathology, we reviewed a total of 23 fetal lung malformations seen at the Children's Hospital of Philadelphia from 1996 to 2004. Twenty-one of the 23 fetal pulmonary malformations could be categorized into 1 of 3 groups based upon the predominant histologic features present within each lesion. Group 1 (9/21) demonstrated tubular airspaces lined by columnar epithelium. Group 2 (6/21) contained airspaces lined by cuboidal epithelium and surrounded by smooth muscle with abundant interstitial mesenchyme. Group 3 (6/21) showed a mixture of relatively mature-appearing airspaces lined by flattened epithelium and scattered dilated bronchiole-like structures. Cysts were of variable size but in all cases showed a respiratory-type lining. Gestational ages ranged from 21 5/7 to 38 2/7 weeks. Patients in groups 1 and 2 were generally younger than those in group 3; however, morphology did not seem to correlate entirely with normal stages of fetal lung development, and group 2 lesions in particular were the least akin to normal fetal lung. In 4 cases a systemic vascular supply to a lobe of lung was identified, providing evidence that such vasculature is embryonic in origin. The histopathology of fetal lung malformations highlights the variability seen in such lesions at all ages, and it is hoped that continued investigations will provide further insight into these enigmatic lesions.

Cystic adenomatoid malformation of the lung: review of genetics, prenatal diagnosis, and in utero treatment

Prenatal identification of lung abnormalities has increased with prenatal surveillance. Treatment usually requires serial ultrasound observation but in rare situations in utero therapy may be required for fetal survival. We review the genetics, prenatal evaluation, and treatment of lung abnormalities with congenital cystic adenomatoid malformation (CCAM). Other lung lesions, bronchopulmonary sequestration (BPS), hybrid lesions involving both malformations, congenital lobar emphysema (CLE), are briefly included as differential diagnosis options. Outcome of fetuses identified to have CCAM lung abnormalities resulting in fetal hydrops and having in utero therapy (thoracoamniotic shunting, fetal thoracotomy, EXIT delivery) are discussed. In the appropriate situation, this maternal fetal surgery approach for CCAM is life-saving for the affected fetus with acceptable maternal morbidity risks in the present and future pregnancies.

Tracheal occlusion in fetal rats alters expression of mesenchymal nuclear transcription factors without affecting surfactant protein expression

BACKGROUND/PURPOSE

Mesenchymal nuclear transcription factors (MNTF) are involved in lung development and maturation and regulate surfactant protein (SP) expression. Prolonged (>2 weeks) fetal tracheal occlusion (TO) has been shown to accelerate lung growth and inhibit pulmonary surfactant synthesis. The effects of TO on SP expression and MNTF, however, have not been formally assessed. The objectives of this study were to evaluate the effects of short-term (3 days) TO on normal lung growth and protein expression of pulmonary MNTF involved in SP synthesis.

METHODS

At E19 (term, 22 days), 2 fetuses per time-dated Sprague-Dawley rats underwent either TO (n = 23) or a sham (n = 22) operation. Lungs were harvested 72 hours post surgery. Pulmonary SP-A; SP-B; SP-C messenger RNA (mRNA) expression; and SP-A and SP-B, Hoxb5, thyroid transcription factor 1, and retinoic X receptor-alpha protein expression were analyzed.

RESULTS

Lung weight was significantly increased by TO (TO 0.32 +/- 0.02g vs SHAM 0.14 +/- 0.01 g; P < .001), resulting in 123% increase of the lung-to-body-weight ratio. No difference of SP-A-mRNA (177 +/- 4.3 TO vs 169 +/- 4.4 SHAM; P = .25), SP-B-mRNA (87.7 +/- 0.2 TO vs 87.4 +/- 0.02 SHAM; P = .33), and SP-C-mRNA (186.5 +/- 3.2 TO vs 183.2 +/- 2.7 SHAM; P = .45) expression was found. Surfactant protein A (175.6 +/- 25.3 TO vs 192.5 +/- 19.8 SHAM; P = .59) and SP-B (163.4 +/- 5.2 TO vs 166.8 +/- 9.3 SHAM; P = .75) protein expression were similar in both groups; however, Hoxb5 (70.3 +/- 18.9 TO vs 130.6 +/- 5.1 SHAM; P = .02) and thyroid transcription factor 1 (102.6 +/- 19 TO vs 181.1 +/- 6.3 SHAM; P = .007) expression were significantly decreased. Retinoic X receptor-alpha expression tended to be increased by TO (171.9 +/- 6.0 TO vs 155.4 +/- 6.7 SHAM; P = .06).

CONCLUSIONS

Short-term TO late in gestation induces rapid lung growth. Surfactant protein-mRNA and protein expression are not significantly altered. Thyroid transcription factor 1 and Hoxb5 are down-regulated by TO, suggesting that duration and timing of occlusion are important in balancing the effects of TO on lung growth vs lung maturation.

Maternal-fetal surgery for myelomeningocele: neurodevelopmental outcomes at 2 years of age

OBJECTIVE

This study was undertaken to examine short-term neurodevelopmental outcomes in children with myelomeningocele (MMC) who underwent in utero neurosurgical closure.

STUDY DESIGN

Between 1998 and 2002, 51 fetuses underwent in utero MMC closure at our Center. Thirty (63%) of these children have returned for neurodevelopmental testing at 2 years of age using the Bayley Scales of Infant Development and Preschool Language Scales.

RESULTS

Overall shunt rate was 43% in this group. Neurodevelopmental testing found 67% with cognitive language and personal-social skills in the normal range, 20% with mild delays, and 13% with significant delays. Children with shunted hydrocephalus scored lower than those with unshunted ventriculomegaly.

CONCLUSION

Children who have undergone fetal MMC closure have characteristic neurodevelopmental deficits that do not appear worsened by fetal surgery, and developmental outcomes may be improved by decreasing the need for ventriculoperitoneal shunting.

Severe pulmonary hypoplasia associated with giant cervical teratomas

BACKGROUND

The use of the ex utero intrapartum treatment (EXIT) procedure has salvaged many fetuses with giant neck masses. Despite an adequate airway, a subset of these patients die from an inability to achieve adequate gas exchange.

METHODS

We reviewed our experience with the EXIT procedure from 1996 to 2004. The EXIT was used to deliver 23 fetuses with giant neck masses.

RESULTS

Three fetuses with giant cervical teratomas died of severe pulmonary hypoplasia. On postmortem, these patients had severe airway distortion by the mass. The carina was retracted superiorly to the first or second rib resulting in compression of the lungs in the apices of the chest and pulmonary hypoplasia. Hypoplasia was reflected in the lung weights of 24 vs 38 g and 17 vs 34 g for age-matched normal lung.

CONCLUSIONS

Unsuspected obstructive fetal neck masses can be fatal because of an inability to secure an airway. Prenatal ultrasonography can identify fetuses at risk, allowing the fetus to be salvaged using the EXIT procedure. Despite obtaining airway control, a subset of these patients will die because of pulmonary hypoplasia. When counseling patients with large cervical masses it is important to discuss potential pulmonary hypoplasia in these patients.

Molecular and immunohistochemical analyses of the focal form of congenital hyperinsulinism

Congenital hyperinsulinism is a rare pancreatic endocrine cell disorder that has been categorized histologically into diffuse and focal forms. In focal hyperinsulinism, the pancreas contains a focus of endocrine cell adenomatous hyperplasia, and the patients have been reported to possess paternally inherited mutations of the ABCC8 and KCNJ11 genes, which encode subunits of an ATP-sensitive potassium channel (K(ATP)). In addition, the hyperplastic endocrine cells show loss of maternal 11p15, where imprinted genes such as p57(kip2) reside. In order to evaluate whether all cases of focal hyperinsulinism are caused by this mechanism, 56 pancreatectomy specimens with focal hyperinsulinism were tested for the loss of maternal allele by two methods: immunohistochemistry for p57(kip2) (n=56) and microsatellite marker analysis (n=27). Additionally, 49 patients were analyzed for K(ATP) mutations. Out of 56 focal lesions, 48 demonstrated clear loss of p57(kip2) expression by immunohistochemistry. The other eight lesions similarly showed no nuclear labeling, but the available tissue was not ideal for definitive interpretation. Five of these eight patients had paternal K(ATP) mutations, of which four demonstrated loss of maternal 11p15 within the lesion by microsatellite marker analysis. All of the other three without a paternal K(ATP) mutation showed loss of maternal 11p15. K(ATP) mutation analysis identified 32/49 cases with paternal mutations. There were seven patients with nonmaternal mutations whose paternal DNA material was not available, and one patient with a mutation that was not present in either parent's DNA. These eight patients showed either loss of p57(kip2) expression or loss of maternal 11p15 region by microsatellite marker analysis, as did the remaining nine patients with no identifiable K(ATP) coding region mutations. The combined results from the immunohistochemical and molecular methods indicate that maternal 11p15 loss together with paternal K(ATP) mutation is the predominant causative mechanism of focal hyperinsulinism.

Long-term outcomes in children treated by prenatal vesicoamniotic shunting for lower urinary tract obstruction

OBJECTIVE

Limited information is available about long-term outcomes in children treated prenatally for lower urinary tract obstruction. Our aim was to evaluate outcomes in children treated in utero with vesicoamniotic shunts.

METHODS

Clinical outcomes in 20 pregnancies with a singleton male fetus, oligo/anhydramnios, and lower urinary tract obstruction were studied using chart review and phone and written clinical questionnaire for parents, pediatricians, and urologists.

RESULTS

Overall 1-year survival was 91%. Two neonatal deaths occurred from pulmonary hypoplasia. Mean gestational age at delivery was 34.6 weeks, mean days from shunting to delivery were 84.4, and mean birth weight was 2,574 g. Prenatal urinary prognosis was good in 13, borderline in 2, and poor in 3 of the survivors. Mean age at follow-up was 5.83 years. Posterior urethral valves were confirmed in 7 males, urethral atresia in 4, and prune belly syndrome in 7. Eight children had acceptable renal function, 4 had mild insufficiency, and 6 required dialysis and eventual renal transplant. Eleven children had normal bladder function with spontaneous voiding, 6 required catheterization, and 1 child still had a vesicostomy. Height and weight were below the 25th percentile in 9 children. Persistent respiratory problems were present in 8, musculoskeletal problems in 9, and frequent urinary tract infections were reported in 9. Health-related quality of life results in our group with lower urinary tract obstruction were similar to those in a healthy child population.

CONCLUSION

Male children who underwent prenatal bladder shunting were neurodevelopmentally normal. Although one third of the surviving babies required dialysis and transplantation, the majority have acceptable renal and bladder function and report satisfactory quality of life.

LEVEL OF EVIDENCE

III.

Retinoic acid induced myelomeningocele in fetal rats: characterization by histopathological analysis and magnetic resonance imaging

The prevention of human neural tube defects by folic acid administration and the potential for fetal surgical intervention for myelomeningocele (MMC) have renewed interest in the molecular pathways and pathophysiology of spina bifida. Animal models for assessment of the early developmental biology and pathophysiology of this lesion are needed. The goal of this study was to develop and characterize a non-surgical rat model of MMC. Time-dated Sprague-Dawley rats were gavage fed different doses of retinoic acid (RA) dissolved in olive oil at E10 (maternal n = 55, fetal n = 505). Control animals received olive oil alone (maternal n = 20, fetal n = 265) or were untreated (maternal n = 5, fetal n = 63). Fetuses were analyzed by detailed histopathology and MRI. Overall, isolated MMC occurred in 60.7% (307/505) of RA-exposed fetuses and no controls. Histopathology confirmed the entire spectrum of severity observed in human MMC, ranging from exposure of the cord with intact neural elements to complete cord destruction. MRI of the brain of MMC fetuses confirmed structural changes similar to humans with Arnold-Chiari malformation, including downward displacement of the cerebellum to just above the foramen magnum and compression of the developing medulla into a small posterior fossa. In conclusion, the RA-induced rat model of MMC is developmentally and anatomically analogous to human MMC. This relatively efficient and cost-effective model of MMC should facilitate investigation of the developmental biology and pathophysiology of MMC, and may be useful for the evaluation of further strategies for prenatal treatment.

Does the use of fentanyl in epidural solutions for postthoracotomy pain management in neonates affect surgical outcome?

BACKGROUND/PURPOSE

Continuous epidural analgesia is routinely used to manage pain in infants undergoing resection of a congenital cystic adenomatoid malformation (CCAM) of the lung. Our aim was to determine if there is a difference in the length of stay (LOS), supplemental analgesic requirements, pain control, and the incidence of adverse respiratory events in infants receiving the 2 standard epidural solutions commonly used: bupivacaine 0.1% and bupivacaine 0.1% with fentanyl 2 to 5 microg/mL.

METHODS

We retrospectively reviewed the charts of infants who received epidural infusions containing bupivacaine 0.1% (n = 18) and bupivacaine 0.1% with fentanyl 2 to 5 microg/mL (n = 10) after CCAM resection during a 12-month period. LOS, rescue opioid, and nonopioid analgesic use, incidence of respiratory depression, and pain scores were recorded.

RESULTS

The LOS in patients receiving fentanyl in their epidural solution was 1 day longer than those receiving plain bupivacaine (median 4 vs 3 days, respectively). Nonopioid analgesic and rescue opioid use was greater in patients who did not have fentanyl in their epidural solutions. Pain ratings were not significantly different. The incidence of respiratory depression was greater in patients receiving epidural infusions containing fentanyl (50% vs 17%, respectively).

CONCLUSION

The addition of fentanyl to epidural infusions of bupivacaine in infants undergoing thoracotomy for resection of CCAM may prolong recovery and increase the incidence of adverse respiratory events without providing a significant analgesic benefit.

Impact of Continuous Intraoperative Monitoring on Outcomes in Open Fetal Surgery

OBJECTIVES

There are shifts in fetal hemodynamics during open fetal surgery that were not appreciated until the use of intraoperative fetal echocardiography. We have developed an intraoperative monitoring strategy to continuously assess fetal hemodynamics. We hypothesized that this approach would enhance intraoperative management and survival.

METHODS

Medical records of open fetal surgery patients were reviewed since the implementation of this approach. Intraoperative fetal monitoring was accomplished by continuous echocardiography, pulse oximetry, establishment of intravenous access, and arterial blood gas and hemoglobin measurement. Overall survival was compared to fetal surgeries performed prior implementation of this monitoring strategy.

RESULTS

Resections of a congenital cystic adenomatoid malformation or a sacrococcygeal teratoma in nine hydropic fetuses were performed while using this monitoring strategy. Intraoperative echocardiography resulted in a change of management in 7 of 9 fetuses. The main observations on fetal echocardiography resulting in intraoperative intervention were decreased ventricular filling, bradycardia, and decreased ventricular contractility. Therapy included administration of volume expanders and/or inotropic agents. Overall fetal survival was 78% compared to a survival of 42% prior to the implementation of this approach.

CONCLUSION

Continuous intraoperative fetal monitoring provides real time assessment of fetal hemodynamics which results in changes in intraoperative management. The overall outcomes in these critically ill fetuses have been improved.

The ex utero intrapartum therapy procedure for high-risk fetal lung lesions

BACKGROUND

Indications for the ex utero intrapartum therapy (EXIT) procedure have expanded to include any fetal anomaly in which resuscitation of the neonate may be compromised.

METHODS

We reviewed the medical records of 9 patients after resection of lung lesions during the EXIT procedure.

RESULTS

The mean gestational age at EXIT procedure was 35.4 weeks. All lung masses maintained large sizes late into gestation with mean mass volume/head circumference ratio of 2.5 at presentation and 2.2 at EXIT. Seven of 9 fetuses demonstrated hydropic changes (n = 6) and/or polyhydramnios (n = 5), and underwent prenatal intervention including thoracentesis, thoracoamniotic shunt placement, amnioreduction, and/or betamethasone administration. Overall survival after EXIT for lung mass resection was 89%. The average time on placental bypass was 65 minutes. Postnatal complications included reoperation for air leak (n = 1), reoperation for bleeding (n = 1), and death from sepsis and prematurity (n = 1). Venoarterial extracorporeal membrane oxygenation was used in 4 neonates for persistent pulmonary hypertension. Maternal prenatal complications included polyhydramnios (n = 5), preterm labor (n = 4), and chorioamnionitis (n = 1). One mother required perioperative blood transfusion.

CONCLUSION

The EXIT procedure allows for controlled resection of large fetal lung lesions at delivery, avoiding acute respiratory decompensation related to mediastinal shift, air trapping, and compression of normal lung.

Surfactant protein expression is increased in the ipsilateral but not contralateral lungs of fetal sheep with left-sided diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) impairs fetal lung growth and increases the density of alveolar epithelial type 2 (AE2) cells. There is controversy whether surfactant protein (SP) expression is altered in CDH. The primary aim of this study was to assess SP expression (mRNA and protein) in the left and right lungs of fetal sheep with and without a diaphragmatic hernia (DH). Left-sided DH was created in four fetal sheep at 65 days of gestational age (g.a.). Sham-operated animals were used as controls. At 138 days g.a., lungs were harvested and the following parameters were measured: SP-A, -B, and -C mRNA expression (Northern blot), SP-A and -B expression (Western blot), and AE2 cell density (immunohistochemistry). The lung weight-to-body weight ratio was reduced by 42% in DH animals. The left-to-right lung weight ratio was lower in DH animals (0.47 +/- 0.03 vs. 0.69 +/- 0.03), indicative of asymmetric lung growth. SP-A, -B, and -C mRNA expression were increased by 61.7%, 32.9%, and 75.5%, respectively, in the left lungs of DH animals. SP-A and SP-B were also increased in DH. In the right lung, SP expression (mRNA and protein) was not different between groups. AE2 cell density was higher (by 67%) in the left but not right lungs of DH animals. Although DH in fetal sheep results in significant lung hypoplasia, SP expression is not reduced. On the contrary, SP expression was increased in the ipsilateral lung of fetuses with left-sided DH. Furthermore, AE2 cell density is increased in DH, suggesting that the increase in SP mRNA and protein levels is due to increases AE2 cell number. Our data further support the premise that fetal lung hypoplasia favors an AE2 phenotype.

Management of fetal mediastinal teratoma

BACKGROUND/PURPOSE

Mediastinal teratomas are rare congenital germ cell tumors that prenatally can compress mediastinal structures and cause hydrops. Two possible presentations of massive fetal mediastinal teratoma include hydrops leading to fetal demise, or fetal esophageal and airway compression causing late-gestation polyhydramnios and preterm labor. The authors present 2 cases of fetal mediastinal teratoma that illustrate successful strategies for either of these presentations.

METHODS

A 37-year-old woman carrying a fetus with a mediastinal mass and secondary hydrops at 23 weeks of gestation underwent in utero resection of the mass. Delivery was by cesarean delivery at 25 weeks because of preterm labor. A 24-year-old mother carrying a fetus with a mediastinal mass and severe polyhydramnios at 36 weeks of gestation underwent an ex utero intrapartum therapy procedure for establishment of an airway and tumor resection on uteroplacental support.

RESULTS

These strategies resulted in physiologic improvement in the first case and controlled resection and resuscitation in the second. The first patient had significant sequelae of prematurity including bronchopulmonary dysplasia but is currently well at 9 months of age. The second patient is well at 1 year of age.

CONCLUSIONS

Massive fetal mediastinal teratoma can result in fetal or neonatal mortality by a variety of mechanisms. Optimal prenatal and perinatal management is required to salvage fetuses compromised by this lesion.

Prenatal Diagnosis and Management of Mainstem Bronchial Atresia

The prenatal diagnosis, natural history and management of mainstem bronchial atresia have not been described previously. We report two cases of prenatally diagnosed proximal bronchial atresia. The first patient presented at 18 weeks with sonographic and MRI findings consistent with bronchial atresia with fetal hydrops. The mother developed the mirror syndrome and labor was induced. A non-viable fetus was delivered at 25 weeks. The second patient presented at 16 weeks gestation with evidence of an intrathoracic mass that was subsequently prenatally diagnosed as a right mainstem bronchial atresia. The right lung increased rapidly in size and was associated with the onset of fetal hydrops. At 24 weeks, fetal pneumonectomy was performed but the fetus expired intraoperatively due to cardiovascular collapse. Post-mortem findings in both cases confirmed the presence of an atretic mainstem bronchus with massive enlargement of the lung. Bronchial atresia involving the mainstem bronchus is associated with a poor prognosis.

Spina bifida

Spina bifida results from failure of fusion of the caudal neural tube, and is one of the most common malformations of human structure. The causes of this disorder are heterogeneous and include chromosome abnormalities, single gene disorders, and teratogenic exposures. However, the cause is not known in most cases. Up to 70% of spina bifida cases can be prevented by maternal, periconceptional folic acid supplementation. The mechanism underlying this protective effect is unknown, but it is likely to include genes that regulate folate transport and metabolism. Individuals with spina bifida need both surgical and medical management. Although surgical closure of the malformation is generally done in the neonatal period, a randomised clinical trial to assess in utero closure of spina bifida has been initiated in the USA. Medical management is a lifelong necessity for individuals with spina bifida, and should be provided by a multidisciplinary team.

Fetal head biometry following in-utero repair of myelomeningocele

OBJECTIVE

To evaluate the impact of prenatal myelomeningocele repair on fetal head biometry.

METHODS

Fifty fetuses underwent open fetal myelomeningocele repair at our institution between January 1998 and July 2002. All had serial head circumference (HC) and lateral ventricular diameter (VD) measurements taken preoperatively and weekly for 8 weeks after repair. Cortical index (CI) was defined as HC/VD. Measurements were compared with gestational age-matched values from nomograms. One-sample t-test, ANOVA and repeated measures analysis were used to assess HC, VD and CI after fetal repair.

RESULTS

Preoperatively, the HC in fetuses with myelomeningocele was smaller than control values (186.4 vs. 198.8 mm, P = 0.0004). Eight weeks' postoperatively this difference had resolved (293 vs. 301.6 mm, P = 0.76). The mean increase in CI after repair was 20% (P = 0.02) compared with the predicted 51% in normal cases. The average increase in VD was 3.9 mm (38.8%, P < 0.001).

CONCLUSIONS

Mid-gestational repair of myelomeningocele alters fetal head growth. Increased CI suggests HC changes are not due to ventriculomegaly alone.

Prenatally diagnosed giant omphaloceles: short- and long-term outcomes

OBJECTIVES

To review prenatal findings, short- and long-term outcomes of giant omphaloceles (GO) managed at a single institution (1996-2001).

METHODS

Prenatal findings and early postnatal outcomes were retrospectively reviewed. Clinical short- and long-term outcomes were analyzed in eight and five children respectively. Parents and physicians of the children were surveyed by written questionnaires about the children's subsequent health issues. (IRB 2002-2-2683).

RESULTS

Seventeen pregnancies with GO were identified: Eight fetuses were live born, four ended in (terminations), two died in utero and three were lost to follow-up. Live-born fetuses had prenatal ascites, extreme levocardia and were delivered by cesarean section at a mean of 37 weeks' gestation with a mean birth weight of 2903 g. All neonates required intubation. Two infants (2/8) died within one year. Four of the six survivors had respiratory insufficiency with a mean ventilation time of 76 days. Respiratory and feeding problems complicated the early neonatal course. Long-term follow-up was available for five patients (mean age of 33.2 months). Asthma, recurrent pulmonary infections, feeding problems, gastroesophageal reflux and failure to thrive were the major problems.

CONCLUSIONS

Respiratory and feeding problems were the most common neonatal and long-term medical management issues. Parents need to be counseled prenatally about the probability of multiple surgeries and long hospitalization following birth.