Imagining and constraining ferrovolcanic eruptions and landscapes through large-scale experiments

Ferrovolcanism, yet to be directly observed, is the most exotic and poorly understood predicted manifestation of planetary volcanism. Large-scale experiments carried out at the Syracuse Lava Project offer insight into the emplacement dynamics of metallic flows as well as coeval metallic and silicate flows. Here, we find that, under the same environmental conditions, higher-density/lower-viscosity metallic lava moves ten times faster than lower-density/higher-viscosity silicate lava. The overall morphology of the silicate flow is not significantly affected by the co-emplacement of a metallic flow. Rather, the metallic flow is largely decoupled from the silicate flow, occurring mainly in braided channels underneath the silicate flow and as low-relief breakouts from the silicate flow front. Turbulent interactions at the metallic-silicate flow interface result in mingling of the two liquids, preserved as erosional surfaces and sharp contacts. The results have important implications for the interpretation of possible ferrovolcanic landscapes across our solar system.

Ferrovolcanism is a hypothetical form of planetary volcanism in which the erupted lava is metallic in composition. Here we show that ferrovolcanic lava is denser and less viscous than silicate lava, resulting in fast-moving, thin, braided flows.

Prenatal Diagnosis of Congenital Diaphragmatic Hernia: Does Laterality Predict Perinatal Outcomes?

OBJECTIVE

The objective of this study was to examine laterality as a predictor of outcomes among fetuses with prenatally diagnosed congenital diaphragmatic hernia (CDH).

METHODS

This is a retrospective cohort study of pregnancies with CDH evaluated at our center from 2008 to 2016 compared cases with right-sided CDH (RCDH) versus left-sided CDH (LCDH). The primary outcome was survival to discharge. Secondary outcomes included ultrasound predictors of poor prognosis (liver herniation, stomach herniation, lung area-to-head circumference ratio [LHR]), concurrent anomalies, hydrops, stillbirth, preterm birth, mode of delivery, small for gestational age, use of extracorporeal membrane oxygenation, and length of stay. Terminations and stillbirths were excluded from analyses of neonatal outcomes.

RESULTS

In this study, 157 (83%) LCDH and 32 (17%) RCDH cases were identified. Survival to discharge was similar (64 vs. 66.4%, p = 0.49) with regard to laterality. RCDH had higher rates of liver herniation (90.6 vs. 72%, p = 0.03), hydrops fetalis (15.6 vs. 1.3%, p < 0.01), and lower LHR (0.87 vs. 0.99, p = 0.04). LCDH had higher rates of stomach herniation (69.4 vs. 12.5%, p < 0.01). Rates of other outcomes were similar in univariate analyses. Adjusting for microarray abnormalities, the odds for survival to discharge for RCDH compared with LCDH was 0.93 (0.38-2.30, p = 0.88).

CONCLUSION

Compared with LCDH, fetuses with RCDH had higher rates of adverse ultrasound predictors, but equivalent survival.

The Management of Myelomeningocele Study: full cohort 30-month pediatric outcomes

BACKGROUND

Previous reports from the Management of Myelomeningocele Study demonstrated that prenatal repair of myelomeningocele reduces hindbrain herniation and the need for cerebrospinal fluid shunting, and improves motor function in children with myelomeningocele. The trial was stopped for efficacy after 183 patients were randomized, but 30-month outcomes were only available at the time of initial publication in 134 mother-child dyads. Data from the complete cohort for the 30-month outcomes are presented here. Maternal and 12-month neurodevelopmental outcomes for the full cohort were reported previously.

OBJECTIVE

The purpose of this study is to report the 30-month outcomes for the full cohort of patients randomized to either prenatal or postnatal repair of myelomeningocele in the original Management of Myelomeningocele Study.

STUDY DESIGN

Eligible women were randomly assigned to undergo standard postnatal repair or prenatal repair <26 weeks gestation. We evaluated a composite of mental development and motor function outcome at 30 months for all enrolled patients as well as independent ambulation and the Bayley Scales of Infant Development, Second Edition. We assessed whether there was a differential effect of prenatal surgery in subgroups defined by: fetal leg movements, ventricle size, presence of hindbrain herniation, gender, and location of the myelomeningocele lesion. Within the prenatal surgery group only, we evaluated these and other baseline parameters as predictors of 30-month motor and cognitive outcomes. We evaluated whether presence or absence of a shunt at 1 year was associated with 30-month motor outcomes.

RESULTS

The data for the full cohort of 183 patients corroborate the original findings of Management of Myelomeningocele Study, confirming that prenatal repair improves the primary outcome composite score of mental development and motor function (199.4 ± 80.5 vs 166.7 ± 76.7, P = .004). Prenatal surgery also resulted in improvement in the secondary outcomes of independent ambulation (44.8% vs 23.9%, P = .004), WeeFIM self-care score (20.8 vs 19.0, P = .006), functional level at least 2 better than anatomic level (26.4% vs 11.4%, P = .02), and mean Bayley Scales of Infant Development, Second Edition, psychomotor development index (17.3% vs 15.1%, P = .03), but does not affect cognitive development at 30 months. On subgroup analysis, there was a nominally significant interaction between gender and surgery, with boys demonstrating better improvement in functional level and psychomotor development index. For patients receiving prenatal surgery, the presence of in utero ankle, knee, and hip movement, absence of a sac over the lesion and a myelomeningocele lesion of ≤L3 were significantly associated with independent ambulation. Postnatal motor function showed no correlation with either prenatal ventricular size or postnatal shunt placement.

CONCLUSION

The full cohort data of 30-month cognitive development and motor function outcomes validate in utero surgical repair as an effective treatment for fetuses with myelomeningocele. Current data suggest that outcomes related to the need for shunting should be counseled separately from the outcomes related to distal neurologic functioning.

The Management of Myelomeningocele Study: obstetrical outcomes and risk factors for obstetrical complications following prenatal surgery

BACKGROUND

The Management of Myelomeningocele Study was a multicenter randomized trial to compare prenatal and standard postnatal closure of myelomeningocele. The trial was stopped early at recommendation of the data and safety monitoring committee and outcome data for 158 of the 183 randomized women published.

OBJECTIVE

In this report, pregnancy outcomes for the complete trial cohort are presented. We also sought to analyze risk factors for adverse pregnancy outcome among those women who underwent prenatal myelomeningocele repair.

STUDY DESIGN

Pregnancy outcomes were compared between the 2 surgery groups. For women who underwent prenatal surgery, antecedent demographic, surgical, and pregnancy complication risk factors were evaluated for the following outcomes: premature spontaneous membrane rupture ≤34 weeks 0 days (preterm premature rupture of membranes), spontaneous membrane rupture at any gestational age, preterm delivery at ≤34 weeks 0 days, nonintact hysterotomy (minimal uterine wall tissue between fetal membranes and uterine serosa, or partial or complete dehiscence at delivery), and chorioamniotic membrane separation. Risk factors were evaluated using χ² and Wilcoxon tests and multivariable logistic regression.

RESULTS

A total of 183 women were randomized: 91 to prenatal and 92 to postnatal surgery groups. Analysis of the complete cohort confirmed initial findings: that prenatal surgery was associated with an increased risk for membrane separation, oligohydramnios, spontaneous membrane rupture, spontaneous onset of labor, and earlier gestational age at birth. In multivariable logistic regression of the prenatal surgery group adjusting for clinical center, earlier gestational age at surgery and chorioamniotic membrane separation were associated with increased risk of spontaneous membrane rupture (odds ratio, 1.49; 95% confidence interval, 1.01-2.22; and odds ratio, 2.96, 95% confidence interval, 1.05-8.35, respectively). Oligohydramnios was associated with an increased risk of subsequent preterm delivery (odds ratio, 9.21; 95% confidence interval, 2.19-38.78). Nulliparity was a risk factor for nonintact hysterotomy (odds ratio, 3.68; 95% confidence interval, 1.35-10.05).

CONCLUSION

Despite the confirmed benefits of prenatal surgery, considerable maternal and fetal risk exists compared with postnatal repair. Early gestational age at surgery and development of chorioamniotic membrane separation are risk factors for ruptured membranes. Oligohydramnios is a risk factor for preterm delivery and nulliparity is a risk factor for nonintact hysterotomy at delivery.

Impact on family and parental stress of prenatal vs postnatal repair of myelomeningocele

BACKGROUND

The Management of Myelomeningocele Study was a multicenter, randomized controlled trial that compared prenatal repair with standard postnatal repair for fetal myelomeningocele.

OBJECTIVE

We sought to describe the long-term impact on the families of the women who participated and to evaluate how the timing of repair influenced the impact on families and parental stress.

STUDY DESIGN

Randomized women completed the 24-item Impact on Family Scale and the 36-item Parenting Stress Index Short Form at 12 and 30 months after delivery. A revised 15-item Impact on Family Scale describing overall impact was also computed. Higher scores reflected more negative impacts or greater stress. In addition, we examined Family Support Scale and Family Resource Scale scores along with various neonatal outcomes. Repeated measures analysis was conducted for each scale and subscale.

RESULTS

Of 183 women randomized, 171 women completed the Impact on Family Scale and 172 completed the Parenting Stress Index at both 12 and 30 months. The prenatal surgery group had significantly lower revised 15-item Impact on Family Scale scores as well as familial-social impact subscale scores compared to the postnatal surgery group (P = .02 and .004, respectively). There was no difference in total parental stress between the 2 groups (P = .89) or in any of the Parenting Stress Index Short Form subscales. In addition, walking independently at 30 months and family resources at 12 months were associated with both family impact and parental stress.

CONCLUSION

The overall negative family impact of caring for a child with spina bifida, up to 30 months of age, was significantly lower in the prenatal surgery group compared to the postnatal surgery group. Ambulation status and family resources were predictive of impact on family and parental stress.

Bladder Function After Fetal Surgery for Myelomeningocele

BACKGROUND

A substudy of the Management of Myelomeningocele Study evaluating urological outcomes was conducted.

METHODS

Pregnant women diagnosed with fetal myelomeningocele were randomly assigned to either prenatal or standard postnatal surgical repair. The substudy included patients randomly assigned after April 18, 2005. The primary outcome was defined in their children as death or the need for clean intermittent catheterization (CIC) by 30 months of age characterized by prespecified criteria. Secondary outcomes included bladder and kidney abnormalities observed by urodynamics and renal/bladder ultrasound at 12 and 30 months, which were analyzed as repeated measures.

RESULTS

Of the 115 women enrolled in the substudy, the primary outcome occurred in 52% of children in the prenatal surgery group and 66% in the postnatal surgery group (relative risk [RR]: 0.78; 95% confidence interval [CI]: 0.57-1.07). Actual rates of CIC use were 38% and 51% in the prenatal and postnatal surgery groups, respectively (RR: 0.74; 95% CI: 0.48-1.12). Prenatal surgery resulted in less trabeculation (RR: 0.39; 95% CI: 0.19-0.79) and fewer cases of open bladder neck on urodynamics (RR: 0.61; 95% CI: 0.40-0.92) after adjustment by child's gender and lesion level. The difference in trabeculation was confirmed by ultrasound.

CONCLUSIONS

Prenatal surgery did not significantly reduce the need for CIC by 30 months of age but was associated with less bladder trabeculation and open bladder neck. The implications of these findings are unclear now, but support the need for long-term urologic follow-up of patients with myelomeningocele regardless of type of surgical repair.

Favorable outcomes in high-risk congenital pulmonary airway malformations treated with multiple courses of maternal betamethasone

BACKGROUND/PURPOSE

Congenital pulmonary airway malformations (CPAMs) are rare congenital lung lesions often diagnosed by prenatal ultrasound. High-risk cases can result in hydrops and prenatal or postnatal demise. Antenatal betamethasone has resulted in improved survival but it is unclear how to manage patients who do not respond to a single course.

METHODS

We present a bi-institutional retrospective review of patients treated with multiple courses of prenatal steroids for high-risk CPAMs between 2007 and 2013.

RESULTS

Nine patients met inclusion criteria. All but one either had an increased CPAM volume ratio (CVR) or number of fluid-containing compartments involved after a single course of antenatal betamethasone, prompting additional courses. Four patients stabilized, three improved and two progressed after the second course. The two cases with disease progression underwent an in utero resection. There were one in utero fetal demise and two deaths within the delivery room. Both fetuses that underwent a fetal resection died. All but one mother who delivered a viable fetus had complications of pregnancy.

CONCLUSIONS

Multiple courses of antenatal betamethasone for high-risk fetal CPAMs often result in favorable short-term outcomes without the need for open fetal resection. Pregnancy complications are common and women within this cohort should be monitored closely.

Plume mapping via hidden Markov methods

This paper addresses the problem of mapping likely locations of a chemical source using an autonomous vehicle operating in a fluid flow. The paper reviews biological plume-tracing concepts, reviews previous strategies for vehicle-based plume tracing, and presents a new plume mapping approach based on hidden Markov methods (HMM). HMM provide efficient algorithms for predicting the likelihood of odor detection versus position, the likelihood of source location versus position, the most likely path taken by the odor to a given location, and the path between two points most likely to result in odor detection. All four are useful for solving the odor source localization problem using an autonomous vehicle. The vehicle is assumed to be capable of detecting above threshold chemical concentration and sensing the fluid flow velocity at the vehicle location. The fluid flow is assumed to vary with space and time, and to have a high Reynolds number (Re>10).

Open fetal surgery for myelomeningocele

In a recently completed randomized, prospective clinical trial, fetal repair for myelomeningocele was shown to result in reduced rates of hydrocephalus requiring placement of a ventriculoperitoneal shunt, improvement in Chiari malformation Type II, and improvement in neurological function compared with standard postnatal repair. Successful fetal surgery requires the active participation and interaction of several clinical teams. Each group has a specific role, and overlap is often required at different points of the treatment plan. Extensive multispecialty discussions with the patient and family are necessary before informed consent can be obtained. Fetal surgery carries significant risks to the mother and fetus and these must be carefully considered prior to a final treatment decision. This review will summarize the evaluation and treatment of patients undergoing fetal repair for myelomeningocele at one institution.

A randomized trial of prenatal versus postnatal repair of myelomeningocele

BACKGROUND

Prenatal repair of myelomeningocele, the most common form of spina bifida, may result in better neurologic function than repair deferred until after delivery. We compared outcomes of in utero repair with standard postnatal repair.

METHODS

We randomly assigned eligible women to undergo either prenatal surgery before 26 weeks of gestation or standard postnatal repair. One primary outcome was a composite of fetal or neonatal death or the need for placement of a cerebrospinal fluid shunt by the age of 12 months. Another primary outcome at 30 months was a composite of mental development and motor function.

RESULTS

The trial was stopped for efficacy of prenatal surgery after the recruitment of 183 of a planned 200 patients. This report is based on results in 158 patients whose children were evaluated at 12 months. The first primary outcome occurred in 68% of the infants in the prenatal-surgery group and in 98% of those in the postnatal-surgery group (relative risk, 0.70; 97.7% confidence interval [CI], 0.58 to 0.84; P<0.001). Actual rates of shunt placement were 40% in the prenatal-surgery group and 82% in the postnatal-surgery group (relative risk, 0.48; 97.7% CI, 0.36 to 0.64; P<0.001). Prenatal surgery also resulted in improvement in the composite score for mental development and motor function at 30 months (P=0.007) and in improvement in several secondary outcomes, including hindbrain herniation by 12 months and ambulation by 30 months. However, prenatal surgery was associated with an increased risk of preterm delivery and uterine dehiscence at delivery.

CONCLUSIONS

Prenatal surgery for myelomeningocele reduced the need for shunting and improved motor outcomes at 30 months but was associated with maternal and fetal risks. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00060606.).

Fetal treatment center: history, infrastructure, and nursing perspective

It is important to recognize that it is only during our lifetime, the last decades of the 20th century, that the fetus has become a patient, with much of the credit due to the powerful imaging and sampling techniques now available. The secret life of the fetus has been revealed and with it the details of normal fetal growth and development and the opportunity to identify, detect, and treat fetal anomalies surgically. From a nursing perspective, this article provides a historical overview of fetal treatment, including the development and evolution of fetal surgery, a description of some milestones of this multifaceted, complex area, a delineation of the components and dynamics of collaborative team management of fetal therapy patients, and finally an introduction to introduce emerging trends that will affect the future of this rapidly evolving field.

Maternal morbidity after maternal-fetal surgery

OBJECTIVE

There is a paucity of published data on the maternal risks of fetal surgical interventions. We analyzed maternal morbidity and mortality that were associated with different types of fetal intervention (open hysterotomy, various endoscopic procedures and percutaneous techniques) to quantify this risk.

STUDY DESIGN

We performed a retrospective evaluation of a continuous series of 187 cases that had been performed between July 1989 and May 2003 at the Fetal Treatment Center, a highly specialized interdisciplinary center for fetal surgery at the University of California, San Francisco. The primary outcome was the frequency of maternal morbidity for open, endoscopic, and percutaneous procedures to access the fetus.

RESULTS

There were 187 pregnant women with confirmed major fetal malformations who were candidates for intrauterine fetal intervention. Maternal-fetal surgery was performed in 87 cases by open hysterotomy, in 69 cases by endoscopic procedures, and in 31 cases by percutaneous techniques. There were no maternal deaths, but significant short-term morbidity was observed. There were no significant differences in the incidence of premature rupture of membranes, pulmonary edema, placental abruption, postoperative vaginal bleeding, preterm delivery, or interval from maternal-fetal surgery to delivery between endoscopic procedures and open surgery. Complications were significantly less in the percutaneous ultrasound-guided procedures. Endoscopic procedures, even with a laparotomy, showed statistically significantly less morbidity compared with the open hysterotomy group regarding cesarean delivery as delivery mode (94.8% vs 58.8%; P < .001), requirement for intensive care unit stay (1.4% vs 26.4%; P < .001), length of hospital stay (7.9 vs 11.9 days; P = .001), and requirement for blood transfusions (2.9% vs 12.6%; P = .022). Chorion-amnion membrane separation (64.7% vs 20.3%; P < .001) was seen more often in the endoscopy group.

CONCLUSION

Short-term morbidities include increased rates of cesarean birth, treatment in intensive care, prolonged hospitalization, and blood transfusion, all of which were more common with hysterotomy compared with other techniques. Maternal-fetal surgery can be performed without maternal death. Results from this study provide helpful data for counseling prospective patients.

A randomized trial of fetal endoscopic tracheal occlusion for severe fetal congenital diaphragmatic hernia

BACKGROUND

Experimental and clinical data suggest that fetal endoscopic tracheal occlusion to induce lung growth may improve the outcome of severe congenital diaphragmatic hernia. We performed a randomized, controlled trial comparing fetal tracheal occlusion with standard postnatal care.

METHODS

Women carrying fetuses that were between 22 and 27 weeks of gestation and that had severe, left-sided congenital diaphragmatic hernia (liver herniation and a lung-to-head ratio below 1.4), with no other detectable anomalies, were randomly assigned to fetal endoscopic tracheal occlusion or standard care. The primary outcome was survival at the age of 90 days; the secondary outcomes were measures of maternal and neonatal morbidity.

RESULTS

Of 28 women who met the entry criteria, 24 agreed to randomization. Enrollment was stopped after 24 patients had been enrolled because of the unexpectedly high survival rate with standard care and the conclusion of the data safety monitoring board that further recruitment would not result in significant differences between the groups. Eight of 11 fetuses (73 percent) in the tracheal-occlusion group and 10 of 13 (77 percent) in the group that received standard care survived to 90 days of age (P=1.00). The severity of the congenital diaphragmatic hernia at randomization, as measured by the lung-to-head ratio, was inversely related to survival in both groups. Premature rupture of the membranes and preterm delivery were more common in the group receiving the intervention than in the group receiving standard care (mean [+/-SD] gestational age at delivery, 30.8+/-2.0 weeks vs. 37.0+/-1.5 weeks; P<0.001). The rates of neonatal morbidity did not differ between the groups.

CONCLUSIONS

Tracheal occlusion did not improve survival or morbidity rates in this cohort of fetuses with congenital diaphragmatic hernia.

Fetoscopic temporary tracheal occlusion for congenital diaphragmatic hernia: prelude to a randomized, controlled trial

OBJECTIVE

As previously reported, high postnatal mortality seen in fetuses with congenital diaphragmatic hernia (CDH) with liver herniation and low lung-to-head ratio (LHR) appears to be improved in fetuses who undergo fetoscopic temporary tracheal occlusion (TO). To test whether further evolution of this technique produces results that justify a randomized controlled trial comparing prenatal intervention to postnatal care, the authors analyzed 11 additional cases and the cumulative experience with 19 cases.

METHODS

The authors analyzed retrospectively the outcome of 11 new and 8 previously reported cases of fetoscopic temporary tracheal occlusion. Various factors were studied including maternal morbidity, antenatal outcome, physiologic lung response, and neonatal course.

RESULTS

Temporary TO can be accomplished using 3 5-mm radially expanding uterine ports without hysterotomy. Obstetric morbidity included mild pulmonary edema in 6 cases, chorioamniotic separation and premature rupture of membranes in 12 patients, and preterm labor and delivery in all patients. Thirteen of 19 (68%) neonates survived for 90 days after delivery; one died in utero, and 5 died after birth. Late mortality included one death caused by sepsis and 2 by complications associated with tracheostomies. Morbidity from gastroesophageal reflux requiring Nissen fundoplication, tracheal injury requiring repair or tracheostomy, and recurrent hernias after diaphragmatic repair were characteristic in longterm survivors.

CONCLUSIONS

Fetoscopic temporary TO may improve outcome in poor-prognosis fetuses with CDH. However, complications related to tracheal dissection, premature delivery and late morbidity are significant. This experience has led to simpler techniques for fetoscopic tracheal occlusion and to an National Institutes of Health-sponsored randomized controlled trial comparing fetoscopic tracheal occlusion with optimal postnatal care.

Fetoscopic temporary tracheal occlusion by means of detachable balloon for congenital diaphragmatic hernia

Occlusion of the fetal trachea blocks the egress of fetal lung fluid and stimulates the growth of hypoplastic lungs in fetuses with diaphragmatic hernia. Accomplishing temporary and reversible occlusion of the fetal trachea has proven difficult without invasive fetal surgery. Using simultaneous real-time ultrasonography and fetal bronchoscopy through a single uterine port, we placed a detachable balloon in the trachea of 2 fetuses with severe diaphragmatic hernia. In both fetuses the fetal lung subsequently enlarged, allowing survival after birth.

Outcome of prenatally diagnosed solid fetal tumors

BACKGROUND/PURPOSE

In the last 10 years, the ability to diagnose fetal tumors in the prenatal period has improved greatly because of technical advances in imaging. Early diagnosis and determination of tumor may affect prognosis.

METHODS

The authors retrospectively reviewed the records of 1316 fetuses who underwent sonographic evaluation for congenital defects at University of California-San Francisco over a 6-year period. Of these, 16 had fetal tumors and were followed up at our institution. There were solid or predominantely solid with small cystic component masses in one of 3 locations: cervical, mediastinal, or abdominal. Excluded from our study were those fetuses with either sacrococcygeal teratoma, congenital cystic adenomatoid malformation of the lung, or ovarian cyst, because these defects have been extensively reviewed elsewhere. In addition, masses that were primarily cystic also were excluded. Data collected included diagnosis, gestational age at diagnosis and at delivery, mode of delivery, fetal and neonatal survival, and disease confirmation.

RESULTS

Of the 16 fetuses, 4 had mediastinal tumors: 2 with pericardial teratomas (both of whom died in utero) and 2 with cardiac rhabdomyomas (1 died; the other presented tuberous sclerosis and is alive at 2 years of age). Four patients had cervical tumors (3 died; 1 survived and is alive and well), and 8 had abdominal tumors (3 with liver tumors, 4 with a left adrenal mass, and 1 with retroperitoneal teratoma). All eight patients with an abdominal tumor are alive and well.

CONCLUSIONS

Fetal tumors are rare, and the prognosis seems to depend on their location and size. Although easier to detect, cervical and mediastinal tumors have a worse prognosis. Abdominal masses are more difficult to detect but have a better prognosis.

Congenital diaphragmatic hernia associated with a gastroesophageal duplication cyst: a case report

Severe left congenital diaphragmatic hernia was diagnosed in a baby prenatally, and she underwent hernia repair on the sixth postnatal day of life. She was found to have a huge symptomatic gastroesophageal duplication cyst on day 24 of life. A thoracoabdominal dissection allowed successful cyst excision. J Pediatr Surg 36:626-628.

Congenital diaphragmatic hernia without herniation of the liver: does the lung-to-head ratio predict survival?

The purpose of the present study was to determine the ability of lung-to-head ratio to predict survival and need for extracorporeal membrane oxygenation support in fetuses with left congenital diaphragmatic hernia without herniation of the liver into the chest. The perinatal records of 20 fetuses with isolated left congenital diaphragmatic hernia without herniation of the left lobe of the liver into the chest were reviewed. Fetuses were stratified into two groups depending on lung-to-head ratio: those with a ratio of less than 1.4 (historically a poor prognosis group) and those with a ratio of greater than 1.4. The outcome of both groups was compared with chi-square analysis. Eight of 11 fetuses with a lung-to-head ratio greater than 1.4 survived, whereas 8 of 9 fetuses with a ratio of less than 1.4 survived. No differences were noted in the need for extracorporeal membrane oxygenation support or survival between the two groups. Fetuses with a prenatally diagnosed left congenital diaphragmatic hernia without herniation of liver into the chest have a favorable prognosis even in the presence of a low lung-to-head ratio.

Successful fetal sacrococcygeal teratoma resection in a hydropic fetus

BACKGROUND/PURPOSE

The development of hydrops in a fetus with a sacroccocygeal teratoma (SCT) usually is a predictor of fetal demise; in utero resection may offer the only chance of survival. Although the authors had performed this procedure in 3 previous cases, they had no long-term patient survival. The authors report a successful case of in utero resection of a fetal sacrococcygeal teratoma.

METHODS

The authors resected a fetal SCT from a 23-weeks-gestation hydropic fetus, using gradually tightening umbilical tapes at the tumor base, electrocautery, and careful sharp dissection. After a blood transfusion, the fetus suffered cardiac arrest but was resuscitated and returned to the uterus.

RESULTS

Postoperatively, residual SCT growth ceased, and hydrops rapidly resolved. Five weeks after the procedure, the infant was delivered because of preterm labor, and, after resection of residual SCT, was discharged home at 3 months of age. She is now a healthy 3 year old.

CONCLUSION

This case shows that successful fetal SCT resection and long-term patient survival is possible.

Successful resuscitation during fetal surgery

After in utero resection of a sacrococcygeal teratoma coupled with a transfusion of packed red blood cells, a 23-week-gestation fetus had bradycardia. Chest compressions were begun and epinephrine, atropine, and sodium bicarbonate were given, while the fetus remained bathed in warm saline. After 3 rounds of drugs, and just before withdrawing support, the fetal heart resumed beating and normal cardiac function. Based on to this case, the authors developed a resuscitation protocol for fetal surgery.

Twin-twin transfusion syndrome: the 'Select' procedure

OBJECTIVES

Twin-twin transfusion syndrome (TTTS) is associated with a high risk of perinatal morbidity and mortality. The condition results from intertwin vascular connections in the shared placenta. We report here a case of early, severe TTTS that failed to respond to serial amniocenteses and that was successfully treated by means of superselective laser coagulation.

METHODS

A causative arteriovenous anastomosis was identified by means of prenatal obstetrical sonography, using color and spectral Doppler techniques. At fetoscopy, performed at 23 weeks' gestation, laser occlusion of only this connection was achieved.

RESULTS

This therapeutic intervention resulted in rapid resolution of all evidence of TTTS and a successful pregnancy outcome, with subsequent delivery of 2 healthy infants at 33 weeks' gestation.

CONCLUSIONS

The potentially fatal pathophysiology of TTTS was reversed by interruption of a single arteriovenous connection. We have termed this the sonographically evaluated, laser-endoscopic coagulation for twins ('Select') procedure.

In utero repair of rectal atresia after complete resection of a sacrococcygeal teratoma

PURPOSE

A case of a fetus with a prenatally diagnosed sacrococcygeal teratoma that produced high-output cardiac failure, hydrops, rectal atresia, and urinary tract obstruction is presented. The unique prenatal surgical management along with the embryogenesis of tumor-related rectal atresia is discussed.

CASE REPORT

A large fetal sacrococcygeal teratoma with a significant intrapelvic component was detected at routine ultrasound in a 35-year-old gravida 3 para 2. Fetal hydrops developed rapidly due to high-output cardiac failure from the vascular 'steal' by the growing tumor. The urinary tract was obstructed due to the intrapelvic tumors mass. At 27 weeks' gestation, the female fetus underwent hysterotomy, resection of the entire mass and urinary diversion via bilateral flank ureterostomies. The rectum was found to be completely atretic due to apparent encasement by the tumor. Pull-through anorectoplasty was carried out concurrently. At 30 weeks' gestation, the mother developed preterm labor and a 1.8-kg was delivered by cesarean section. The baby did very well for 3 days but had a cardiac arrest and died due to an atrial perforation by a transfemoral venous catheter.

CONCLUSIONS

To our knowledge this is the first report of a complete prenatal resection of a sacrococcygeal teratoma with concomitant pull-through anorectoplasty for rectal atresia.

Cord ultrasonic transection procedure for selective termination of a monochorionic twin

Placental vascular communications can present a life-threatening problem in monochorionic twins when one fetus has a lethal anomaly. Although selective feticide is the best option for salvaging the normal twin, techniques normally employed (i.e. intracardiac potassium, air embolism) are not prudent given the common circulatory system. Furthermore, in monoamniotic, monochorionic twin gestations it is important to transect the umbilical cord completely to prevent entanglement of the dead fetus around the cord of the normal twin. We present two cases of monochorionic twins in which the cords were transected with a harmonic scalpel under ultrasonic guidance via one trocar. The harmonic scalpel is an instrument which can simultaneously coagulate and cut blood vessels or tissues. The cord ultrasonic transection procedure is a novel, minimally invasive technique which offers several advantages over the methods currently used for selective feticide in discordant monochorionic twin gestations.

Maternal fertility is not affected by fetal surgery

The purpose of this report is to assess the impact of fetal surgery on future maternal fertility, subsequent pregnancy outcome, and the incidence of pregnancy complications. Retrospective data were collected on 70 mothers who underwent fetal surgery between April 1981 and June 1996. Indications for open hysterotomy fetal surgery included congenital diaphragmatic hernia (n = 44), congenital cystic adenomatoid malformation of the lung (n = 11), urinary obstruction (n = 9), sacrococcygeal teratoma (n = 4), heart block (n = 1), and acardiac-acephalic twin reduction (n = 1). The following data were obtained: number of pregnancy attempts, number of successful pregnancies, pregnancy outcome including obstetrical and neonatal complications, and infertility after fetal surgery. There were 45 respondents, of whom 35 attempted subsequent pregnancies. Thirty-two were successful, resulting in 31 livebirths. Two women had a strong prefetal surgery history of infertility, 1 has only attempted to conceive for 3 months. We report this experience because the effect of open fetal surgery on futrue fertility is such an important question for our patients and referring physicians. This analysis suggests that hysterotomy and open fetal surgery has a negligible impact on maternal fertility.

Fetal neurenteric cyst causing hydrops: case report and review of the literature

Routine prenatal ultrasound revealed a unilocular cystic mass associated with upper thoracic hemivertebrae that grew to 6 cm at 28 weeks and was associated with hydrops. A thoraco-amniotic shunt decompressed the cyst and resolved the hydrops, but the shunt occluded 17 days later. Preterm labour led to vaginal delivery at 31 2/7 weeks. Postnatally, the cyst was decompressed by thoracentesis due to respiratory distress. It was resected on day four of life. Severe tracheobronchomalacia was present post-operatively, presumably due to prenatal mass effect of the cyst. At one year of age, the child has recovered completely without adverse respiratory or neurological sequelae.

Fetal liver position and perinatal outcome for congenital diaphragmatic hernia

Despite advances in postnatal care, patients born with a congenital diaphragmatic hernia (CDH) suffer substantial morbidity and mortality. The present study was undertaken to determine the prognostic influence of prenatally-diagnosed liver herniation in the hemithorax in fetuses with CDH. The medical records of 48 patients evaluated for a prenatally-diagnosed left CDH were retrospectively reviewed. Patients were analysed according to the position of the liver by prenatal ultrasound; 32 fetuses had a major portion of the liver herniated into the left hemithorax ('liver up') and 16 had an intra-abdominal liver ('liver down'). Liver position was determined using colour-flow Doppler ultrasonography. There were two fetal deaths in the liver-up group and one in the liver-down group. The liver-up group more frequently required extracorporeal membrane oxygenation (ECMO) support (53 per cent) compared with the liver-down group (19 per cent). Postnatal survival was significantly less in the liver-up group (43 per cent) vs. the liver-down group (93 per cent). Fetuses with congenital diaphragmatic hernia and liver herniated into the hemithorax have a much worse prognosis than similarly afflicted fetuses without liver herniation. Prenatal ultrasonographic diagnosis of congenital diaphragmatic hernia allows for preparation for a critically ill newborn and aids in prenatal family counselling.

Neurodevelopmental outcome after open fetal surgery

PURPOSE

This study examined the neurological and age-appropriate developmental outcomes of 11 children who underwent open fetal surgery.

RESULTS

Nine children have normal neurological outcomes, and nine have normal development.

CONCLUSION

Intensive postnatal care, intracranial hemorrhage, and requirement for prolonged respiratory support were associated with a worse neurological and developmental prognosis.

Correction of congenital diaphragmatic hernia in utero IX: fetuses with poor prognosis (liver herniation and low lung-to-head ratio) can be saved by fetoscopic temporary tracheal occlusion

BACKGROUND/PURPOSE

Fetuses with congenital diaphragmatic hernia (CDH) who have a "poor prognosis" with postnatal treatment now can be identified on the basis of liver herniation, early diagnosis (before 25 weeks' gestation) and a low lung-to-head ratio (LHR). Because complete in utero repair proved unsuccessful for this group, the strategy of temporary tracheal occlusion was developed to gradually enlarge the hypoplastic fetal lung. The purpose of this study is to compare the outcome of patients in the poor-prognosis group treated by one of three methods: (1) standard postnatal care, (2) fetal tracheal occlusion via open hysterotomy, and (3) the recently developed video-fetoscopic (Fetendo) technique of tracheal occlusion without hysterotomy.

METHODS

In the past 3 years, 34 of 86 fetuses with an isolated left CDH met criteria for the poor-prognosis group. Thirteen families chose postnatal treatment at an extracorporeal membrane oxygenation (ECMO) center, 13 underwent open fetal tracheal occlusion, and eight underwent fetoscopic tracheal occlusion.

RESULTS

The survival rate was 38% in the group treated by standard postnatal therapy, 15% in the open tracheal occlusion group, and 75% in the Fetendo group. There were less postoperative pulmonary complications noted in mothers who underwent the Fetendo procedure versus the open tracheal occlusion. All but one Fetendo clip patient had a striking physiological response demonstrated by sonographic enlargement of the small left lung that was documented postnatally by plain radiographs and its subjective appearance during repair of the CDH. In contrast, only 5 of the 13 open tracheal occlusion patients demonstrated lung growth.

CONCLUSION

Fetuses with a left CDH who have liver herniation and a low LHR are at high risk of neonatal demise and appear to benefit from temporary tracheal occlusion when performed fetoscopically, but not when performed by open fetal surgery.

Prospective analysis of lung-to-head ratio predicts survival for patients with prenatally diagnosed congenital diaphragmatic hernia

BACKGROUND

Accurate prenatal prediction of outcome for fetuses who have congenital diaphragmatic hernia (CDH) is very difficult. The authors previously reported a retrospective analysis of risk factors for fetal CDH and proposed a new index of severity: the lung-to-head ratio (LHR). The authors now report a prospective study to test whether this new index predicts neonatal outcome.

METHODS

Fifteen patients who had left-sided CDH were sonographically evaluated at the University of California, San Francisco (UCSF) and followed prenatally and postnatally. LHR was measured at 24 to 26 weeks' gestation. Outcome variables included survival and the need for extracorporeal membrane oxygenation (ECMO).

RESULTS

Overall survival was 47%. LHR ranged from 0.62 to 1.86. No patient with an LHR of less than 1.0 (n = 3) survived despite ECMO, whereas all patients with an LHR greater than 1.4 survived (n = 4), one requiring ECMO. LHR values between 1.0 to 1.4 were associated with 38% survival (n = 8), 75% requiring ECMO. Overall, survivors had a mean LHR of 1.4 +/- 0.33 and nonsurvivors, 1.05 +/- 0.3 (P < .05).

CONCLUSION

The LHR is a useful index to help predict neonatal outcome in patients who have left-sided CDH.

Correction of congenital diaphragmatic hernia in utero VII: a prospective trial

BACKGROUND

Congenital diaphragmatic hernia (CDH) remains an unsolved problem. Despite optimal postnatal care, up to 60% of CDH babies die. Experimental evidence and clinical experience have shown that in utero repair of CDH is feasible and can reverse pulmonary hypoplasia, but only in fetuses without liver herniation. For this subgroup, the safety and efficacy of repair before birth has not been compared with standard care after birth.

METHODS

Four fetuses in whom CDH without liver herniation was diagnosed underwent open fetal surgery for repair of the CDH. Seven comparison fetuses were treated conventionally. Neonatal mortality was the principle outcome variable. Secondary outcome variables included death of all causes until 2 years of age, number of days of ventilatory support, length of hospital stay, requirement for extracorporeal membrane oxygenation (ECMO), and total hospital charges.

RESULTS

There was no difference in survival between the fetal surgery group and the postnatally treated comparison group (75% v 86%). Fetal surgery patients were born more prematurely than the comparison group (32 weeks v 38 weeks' gestation). Length of ventilatory support and requirement for ECMO were equivalent in the fetal surgery group and the postnatally treated comparison group. Length of hospital stay and hospital charges did not differ between the groups.

CONCLUSIONS

Open fetal surgery is physiologically sound and technically feasible, but does not improve survival over standard postnatal treatment in the subgroup of CDH fetuses without liver herniation, primarily because overall survival in this subgroup is favorable with or without prenatal intervention. These data suggest that fetuses who have prenatally diagnosed CDH and without evidence of liver herniation should be treated postnatally.

Familial diaphragmatic agenesis: an autosomal-recessive syndrome with a poor prognosis

Diaphragmatic agenesis is a severe form of congenital diaphragmatic hernia for which an autosomal recessive form of inheritance has been proposed. The authors report six families with 13 pregnancies with diaphragmatic agenesis in which inheritance followed an autosomal recessive pattern, including the first reported case of bilateral diaphragmatic agenesis in twins. None of the thirteen affected fetuses survived. Familial diaphragmatic agenesis appears to be a distinct clinical entity with a worse prognosis than posterolateral diaphragmatic hernia.

Correction of congenital diaphragmatic hernia in utero VIII: Response of the hypoplastic lung to tracheal occlusion

Most fetuses with congenital diaphragmatic hernia (CDH) diagnosed before 24 weeks' gestation die despite optimal postnatal care. In fetuses with liver herniation into the chest, prenatal repair has not been successful. In the course of exploring the pathophysiology of CDH and its repair in fetal lambs, the authors found that obstructing the normal egress of fetal lung fluid enlarges developing fetal lungs, reduces the herniated viscera, and accelerates lung growth, resulting in improved pulmonary function after birth. They developed and tested experimentally a variety of methods to temporarily occlude the fetal trachea, allow fetal lung growth, and reverse the obstruction at birth. The authors applied this strategy of temporary tracheal occlusion in eight human fetuses with CDH and liver herniation at 25 to 28 weeks' gestation. With ongoing experimental and clinical experience, the technique of tracheal occlusion evolved from an internal plug (two patients) to an external clip (six patients), and a technique was developed for unplugging the trachea at the time of birth (Ex Utero Intrapartum Tracheoplasty [EXIT]). Two fetuses had a foam plug placed inside the trachea. The first showed dramatic lung growth in utero and survived; the second (who had a smaller plug to avoid tracheomalacia) showed no demonstrable lung growth and died at birth. Two fetuses had external spring-loaded aneurysm clips placed on the trachea; one was aborted due to tocolytic failure, and the other showed no lung growth (presumed leak) and died 3 months after birth. Four fetuses had metal clips placed on the trachea. All showed dramatic lung growth in utero, with reversal of pulmonary hypoplasia documented after birth. However, all died of nonpulmonary causes. Temporary occlusion of the fetal trachea accelerates fetal lung growth and ameliorates the often fatal pulmonary hypoplasia associated with severe CDH. Although the strategy is physiologically sound and technically feasible, complications encountered during the evolution of these techniques have limited the survival rate. Further evolution of this technique is required before it can be recommended as therapy for fetal pulmonary hypoplasia.