The making of fetal surgery

Fetal diagnosis prompts the question for fetal therapy in highly selected cases. Some conditions are suitable for in utero surgical intervention. This paper reviews historically important steps in the development of fetal surgery. The first invasive fetal intervention in 1963 was an intra-uterine blood transfusion. It took another 20 years to understand the pathophysiology of other candidate fetal conditions and to develop safe anaesthetic and surgical techniques before the team at the University of California at San Francisco performed its first urinary diversion through hysterotomy. This procedure would be abandoned as renal and pulmonary function could be just as effectively salvaged by ultrasound-guided insertion of a bladder shunt. Fetoscopy is another method for direct access to the feto-placental unit. It was historically used for fetal visualisation to guide biopsies or for vascular access but was also abandoned following the introduction of high-resolution ultrasound. Miniaturisation revived fetoscopy in the 1990 s, since when it has been successfully used to operate on the placenta and umbilical cord. Today, it is also used in fetuses with congenital diaphragmatic hernia (CDH), in whom lung growth is triggered by percutaneous tracheal occlusion. It can also be used to diagnose and treat urinary obstruction. Many fetal interventions remain investigational but for a number of conditions randomised trials have established the role of in utero surgery, making fetal surgery a clinical reality in a number of fetal therapy programmes. The safety of fetal surgery is such that even non-lethal conditions, such as myelomeningocoele repair, are at this moment considered a potential indication. This, as well as fetal intervention for CDH, is currently being investigated in randomised trials.

Perinatal and early surgical outcome for the fetus with hypoplastic left heart syndrome: a 5-year single institutional experience

OBJECTIVES

To review our experience with the prenatal diagnosis of hypoplastic left heart syndrome (HLHS). Our goal was to establish the benchmark for perinatal and early surgical outcome in the current era, from a center with an aggressive surgical approach and a cohort with a high level of intention-to-treat.

METHODS

Outcome was assessed in fetuses with HLHS following stratification into high-risk and standard-risk categories. High risk was defined as the presence of any of the following: extracardiac, genetic or chromosomal anomalies; prematurity of < 34 weeks' gestation; additional cardiac findings such as intact or highly restrictive atrial septum, severe degree of tricuspid regurgitation or severe ventricular dysfunction. Standard risk was defined as absence of these risk factors.

RESULTS

Of 240 fetuses evaluated over 5 years, 162 (67.5%) were in the standard-risk group and 78 (32.5%) were in the high-risk group. Of the 240 sets of parents, 38 (15.8%) chose termination or non-intervention at birth at initial prenatal counseling and 185 of the neonates (77.1%) underwent first-stage Norwood surgery with 155 surviving and 30 deaths, giving an overall Norwood operative survival of 83.8%. Breakdown by risk class reveals a significant Norwood operative survival advantage for the standard-risk group (92.8%) over the high-risk group (56.5%) (P < 0.001).

CONCLUSIONS

Following prenatal diagnosis of HLHS, families should be strongly encouraged to undertake comprehensive prenatal evaluation in order to obtain an accurate prognosis. One-third have additional risk factors that limit survival outcome, however two-thirds do not and have an excellent chance of early survival.

Reproductive outcomes in subsequent pregnancies after a pregnancy complicated by open maternal-fetal surgery (1996-2007)

OBJECTIVE

The reproductive and gynecologic outcomes for women after the pregnancy complicated by open maternal-fetal surgery (OMFS) were evaluated.

STUDY DESIGN

The retrospective review identified 93 women with OMFS from a single institution (1996-2007). Consent and questionnaires were sent to women. Institutional review board approval was obtained from the Committee for Protection of Human Subjects.

RESULTS

The total return rate was 57.3%. Total pregnancies reported were 47, with 36 delivering after 20 weeks' gestation. The uterine dehiscence and rupture rates were 14% and 14%, respectively. Fetal anomalies occurred in 4 subsequent pregnancies. Normal conception occurred in 98% of subsequent pregnancies. Gynecologic issues were reported by 8 women, with infertility, abdominal pain, and ovarian and uterine factors.

CONCLUSION

The reproductive outcomes of uterine dehiscence (14%) and rupture (14%) in a subsequent pregnancy continue to be a major counseling issue for OMFS. Fertility and gynecologic factors do not appear to be increased for women undergoing OMFS.

Predicting the severity of congenital high airway obstruction syndrome

BACKGROUND

Congenital high airway obstruction syndrome (CHAOS) is caused by complete or near-complete obstruction of the fetal airway. Obstruction sets in motion a sequence of events that can ultimately lead to fetal demise. However, on rare occasions in utero airway decompression occurs, reversing syndromic findings and improving the prognosis. In our relatively large series of CHAOS patients, we have observed a spectrum of clinical severity. The aim of this study was to identify the prenatal characteristics of CHAOS predictive of a milder postnatal course.

METHODS

The medical charts of all fetuses observed at our institution with the diagnosis of CHAOS were reviewed for radiologic findings, delivery information, perinatal course, autopsy or discharge report, and long-term follow-up.

RESULTS

Between 1996 and 2008, 12 fetuses with CHAOS were identified. Four fetuses had no evidence of hydrops on initial imaging. Of the 8 fetuses displaying hydrops, 3 were terminated, 2 died in utero, and 1 with multiple anomalies died at birth. Six fetuses were delivered via the ex utero intrapartum therapy procedure for attempted salvage, and 5 of the 6 survived the neonatal period including all 4 fetuses without hydrops. Serial prenatal imaging demonstrated less severe signs of CHAOS in 3 fetuses, and in 2 of them, direct laryngoscopy revealed a tiny opening in the airway. All 3 fetuses that showed improvement on serial imaging survived the neonatal period and were discharged home by 2-10 weeks of age.

CONCLUSIONS

Although the natural history of CHAOS is variable, trends in prenatal ultrasound findings are highly predictive of postnatal outcome and are a valuable guide to prenatal counseling.

Species number and endemism: the galapagos archipelago revisited

Regression analyses to determine plant species number are repeated for the Galápagos Islands with new data. The multiple curvilinear regression gives the best prediction of species number, with island area making the only significant contribution. The proportion of species endemic to the Galápagos is highest in the arid, transition zone and on small islands, and lowest in the littoral and mesic zones. This is explained in terms of zone-specific immigration and extinction rates and the very recent appearance of moist upland climates in the archipelago.

Outcomes in a cohort of patients with Stage I twin-to-twin transfusion syndrome

OBJECTIVE

To determine pregnancy outcomes of patients who present with Stage I twin-to-twin transfusion syndrome (TTTS).

METHODS

This was a retrospective review of all patients with TTTS referred to our institution between January 2005 and December 2006. Quintero criteria were used for staging. Laser ablation was not offered to patients with Stage I disease.

RESULTS

A total of 155 twin pregnancies were evaluated for TTTS during this period. Forty-two met the criteria for Stage I and were included in the analysis. The overall survival to discharge was 82%. The mean gestational age at the time of consultation was 20.9 +/- 0.4 weeks. A total of 23 cases (54.8%) underwent amnioreduction. Progression of TTTS requiring invasive therapy occurred in four cases. The mean gestational age at delivery was 32.5 +/- 0.62 weeks. When divided according to use of amnioreduction, there were no statistically significant differences between the groups for gestational age at delivery or for birth weight. Those Stage I cases with a CHOP cardiovascular score of 5 or higher delivered almost 3 weeks earlier than the remainder of the cohort.

CONCLUSIONS

Progression of TTTS beyond Stage I occurred in only 9.5% of the cohort. Mean gestational age at delivery and survival to discharge did not differ between Stage I patients and those treated with placental laser ablation for more advanced stages of TTTS.

The relationship of seizure activity and chronic epilepsy in early infancy and short-term neurodevelopmental outcome following fetal myelomeningocele closure

We explored the relationship between seizure activity (SA) and/or chronic epilepsy (CE) and short-term neurodevelopmental outcomes following fetal myelomeningocele (fMMC) surgery. Retrospective databases and a parental questionnaire focusing on common complications of hindbrain herniation associated with MMC were used to determine the incidence of seizures following fMMC surgery. The Bayley Scales of Infant Development II was used to evaluate the neurocognitive outcomes. The available 3-year outcome data were used for analysis. 54 children underwent fMMC closure at our institution between 1998 and 2003. 48 (89%) families participated. The shunt rate was 50% (n=24). Seizures developed in 8/48 (17%) children, 2 (8%) non-shunted and 6 (25%) shunted (P=0.07). Of those six, 3 developed CE. Neurodevelopmental scores in the average range were found in both non-shunted and 3 shunted fMMC children. The remaining 3 shunted toddlers had CE and significant neurodevelopmental delays. Of those, 2 had severe intracranial hemorrhage and one developed frequent apneic spells in combination with epilepsy. The incidence of seizures in fMMC children was similar to previously reported data of postnatally repaired MMC patients. SA alone without CE was not associated with a worse neurocognitive outcome. The occurrence of severe acquired intracranial injury and CE, however, appeared to be correlated with adverse neurocognitive outcome following fMMC surgery.

Fronts, jumps and secondary introductions suggested as different invasion patterns in marine species, with an increase in spread rates over time

Not all introduced (invasive) species in a region will spread from a single point of introduction. Long-distance dispersal or further introductions can obscure the pattern of spread, but the regional importance of such processes is difficult to gauge. These difficulties are further compounded when information on the multiple scale process of invasive species range expansion is reduced to one-dimensional estimates of spread (e.g. km yr(-1)). We therefore compared the results of two different metrics of range expansion: maximum linear rate of spread and accumulation of occupied grid squares (50 x 50 km) over time. An analysis of records for 54 species of introduced marine macrophytes in the Mediterranean and northeast Atlantic revealed cases where the invasion process was probably missed (e.g. Atlantic Bonnemaisonia hamifera) and suggested cases of secondary introductions or erratic jump dispersal (Dasysiphonia sp. and Womersleyella setacea). A majority of species analysed showed evidence for an accumulation of invaded sites without a clear invasion front. Estimates of spread rate are increasing for more recent introductions. The increase is greater than can be accounted for by temporally varying search effort and implies a historical increase in vector efficiency and/or a decreased resistance of native communities to invasion.

Prenatal diagnosis and postnatal outcome of fetal spinal defects without Arnold-Chiari II malformation

OBJECTIVE

To determine the prenatal evolution/natural history and postnatal outcome of fetuses diagnosed with a neural tube defect (NTD) lacking the Arnold-Chiari-II malformation (ACM II).

MATERIAL AND METHODS

This retrospective study reviewed 16 fetuses evaluated with ultrasound (US) and MRI at a single referral center from 1/2000 to 8/2007. Follow-up studies and available postnatal outcomes were reviewed.

RESULTS

Postpartum diagnosis was terminal myelocystoceles 7/16 (44%); myelomeningoceles (MMCs) 3/16 (19%); lipomyelomeningoceles 2/16(13%); and thoracic myelocystocele 1/16 (6%). Three patients (19%) were lost to follow-up or termination of pregnancy. Two prenatally diagnosed 'closed' NTD were postnatally found to be MMCs. Three of the myelocystoceles had additional omphalocele, bladder extrophy, imperforate anus and spinal defect (OEIS complex). For the total cohort, impaired lower extremity function was seen in 38%, impaired bladder function in 64%, and ventriculoperitoneal shunting in 8%. Four fetuses with a myelocystocele developed hindbrain herniation in the third trimester of pregnancy. The preterm delivery rate was 38%. Five of eight (63%) neonates with postnatally diagnosed myelocystoceles had mothers with a body mass index over 30.

CONCLUSION

Prenatal differentiation between closed and open NTD is not always possible. Postnatal outcome of isolated myelocystocele and MMC seems to be more favorable than for an NTD with ACM II (shunt requirement). Incontinence is the major childhood morbidity. Maternal obesity may be a risk factor for closed NTDs.

Fetal thoracic and bladder shunts

Congenital obstructive lesions involving the bladder and the lung can lead to serious complications for the newborn. The in-utero placement of a diverting shunt in the fetal bladder or thoracic cavity can decrease the morbidity and mortality associated with these obstructive conditions. This review focuses on the indications for prenatal evaluation, technique, and outcomes for those fetuses with a lower urinary tract obstruction, congenital pleural effusion or macrocystic congenital cystic adenomatoid malformation after placement of a vesicoamniotic or thoracoamniotic shunt.

Haploidentical in utero hematopoietic cell transplantation improves phenotype and can induce tolerance for postnatal same-donor transplants in the canine leukocyte adhesion deficiency model

In the murine model, in utero hematopoietic cell transplantation (IUHCT) has been shown to achieve low levels of allogeneic chimerism and associated donor-specific tolerance permitting minimal conditioning postnatal hematopoietic stem cell transplantation (HSCT). In this pilot study, we investigated IUHCT in the canine leukocyte adhesion deficiency (CLAD) model. Haploidentical IUHCT resulted in stable low-level donor cell chimerism in all dogs that could be analyzed by sensitive detection methodology (4 of 10) through 18 months of follow-up. In the 2 CLAD recipients, low-level chimerism resulted in amelioration and complete reversal of the CLAD phenotype, respectively. Six recipients of IUHCT (5 carriers and 1 CLAD) subsequently received postnatal HSCT from the same haploidentical prenatal donor after minimal conditioning with busulfan 10 mg/kg. Chimerism in 2 of 5 CLAD carriers that underwent HSCT increased from < 1% pre-HSCT to sustained levels of 35% to 45%. Control animals undergoing postnatal haploidentical HSCT without IUHCT had no detectable donor chimerism. These results demonstrate that haploidentical IUHCT in the CLAD model can result in low-level donor chimerism that can prevent the lethal phenotype in CLAD dogs, and can result in donor-specific tolerance that can facilitate postnatal minimal conditioning HSCT.

Like a rolling stone: the mobility of maerl (Corallinaceae) and the neutrality of the associated assemblages

Beds of nonattached coralline algae (maerl or rhodoliths) are widespread and considered relatively species rich. This habitat is generally found in areas where there is chronic physical disturbance such that maerl thalli are frequently moved. Little is known, however, about how natural disturbance regimes affect the species associated with maerl. This study compared the richness, animal abundance, and algal biomass of maerl-associated species over a two-year period in a wave-disturbed bed and a sheltered maerl bed. Changes in associated species over time were assessed for departures from a neutral model in which the dissimilarity between samples reflects random sampling from a common species pool. Algal biomass and species richness at the wave-exposed site and on stabilized maerl at the sheltered site were reduced at times of higher wind speeds. The changes in species richness were not distinguishable from a neutral model, implying that algal species were added at random to the assemblage as the level of disturbance lessened. Results for animal species were more mixed. Although mobile species were less abundant during windy periods at the exposed site, both neutral and non-neutral patterns were evident in the assemblages. Artificial stabilization of maerl had inconsistent effects on the richness of animals but always resulted in more attached algal species. While the results show that the response of a community to disturbance can be neutral, the domain of neutral changes in communities may be relatively small. Alongside non-neutral responses to natural disturbance, artificial stabilization always resulted in an assemblage that was more distinct than would be expected under random sampling from a common pool. Community responses to stabilization treatments did not consistently follow the predictions of the dynamic equilibrium model, the intermediate disturbance model, or a facilitation model. These inconsistencies may reflect site-specific variation in both the disturbance regime and the adjacent habitats that provide source populations for many of the species found associated with maerl.

In utero meconium passage in fetuses and newborns with myelomeningocele

OBJECT

The authors retrospectively investigated whether midgestational fetal myelomeningocele (fMMC) repair alters intrauterine meconium exposure.

METHODS

Prior to the National Institutes of Health Management of Myelomeningocele Study, 54 fetuses underwent fMMC repair at the authors' institution. Forty-six fMMC sacs were available for pathological examination and 53 MMC sacs from postnatally repaired MMCs (pMMCs) were available for comparison. The presence and distribution of meconium were blindly evaluated using a grading system defined as follows: absent (no meconium present), mild (<10 meconium-positive histiocytes [MPHs]/hpf), moderate (10-25 MPHs/hpf), and severe (>25 MPHs/hpf). Hall's bile stain was used to confirm meconium and Prussian blue and Fontana Masson stains to exclude hemosiderin and melanin, respectively.

RESULTS

Compared to pMMCs (79%), meconium histiocytosis was less prevalent in fMMC sacs (57%; p=0.017). Meconium staining was completely absent in 43% of the fMMC sacs. Mild meconium histiocytosis was found in 35% fMMC and 61% pMMC sacs (p=0.035). There was no statistical difference between groups with moderate and severe meconium histiocytosis.

CONCLUSIONS

Meconium passage in MMCs can occur early in fetal life. Fetal MMC repair may reduce the duration of meconium exposure, thereby potentially limiting the toxic injury to the vulnerable neural elements.

Lower extremity neuromotor function and short-term ambulatory potential following in utero myelomeningocele surgery

OBJECTIVE

To evaluate lower extremity neuromotor function (LENF) and short-term ambulatory potential following fetal myelomeningocele (fMMC) closure.

METHODS

Retrospective chart review of 54 children that underwent fMMC closure at our institution prior to the NIHCD-MOMS trial. Neonatal LENF was compared to predicted function based on spinal lesion level assigned by prenatal ultrasound. Ambulatory status was classified as independent walkers (walks without assistive appliances), assisted walker (requires walking aid), and non-ambulatory (wheelchair bound).

RESULTS

Thoracic, lumbar, and sacral level lesions were present in 4, 44 and 6 fMMC infants, respectively. 31/54 of fMMC children (57.4%; median: 2 levels, range: 1-5) had better than predicted, 13/54 (24.1%) same as predicted and 10/54 (18.5%; median: 1 level, range: 1-2) worse than predicted LENF at birth. At a median follow-up age of 66 months (36-113), 37/54 (69%) walk independently, 13/54 (24%) are assisted walkers, and 4/54 (7%) are wheelchair dependent. The strongest factors predicting a lower likelihood to walk independently were higher-level lesion (>L4, p = 0.001) and the development of clubfoot deformity after fetal intervention (p = 0.026). Despite the observed improved ambulatory status, structured evaluation of coordinative skills revealed that the majority of independent ambulators and all children that require assistive devices to walk experience significant deficits in lower extremity coordination.

CONCLUSIONS

We observed that fMMC surgery in this highly selective population results in better than predicted LENF at birth and short-term ambulatory status. However, fMMC toddlers continue to demonstrate deficits in movement coordination that are characteristic for children with spina bifida.

Genetic association of the activin A receptor gene (ACVR2A) and pre-eclampsia

Pre-eclampsia is a common serious disorder of human pregnancy, which is associated with significant maternal and perinatal morbidity and mortality. The suspected aetiology of pre-eclampsia is complex, with susceptibility being attributable to multiple environmental factors and a large genetic component. Recently, we reported significant linkage to chromosome 2q22 in 34 Australian/New Zealand (Aust/NZ) pre-eclampsia/eclampsia families, and activin A receptor type IIA (ACVR2A) was identified as a strong positional candidate gene at this locus. In an attempt to identify the putative risk variants, we have now comprehensively re-sequenced the entire coding region of the ACVR2A gene and the conserved non-coding sequences in a subset of 16 individuals from these families. We identified 45 single nucleotide polymorphisms (SNPs), with 9 being novel. These SNPs were genotyped in our total family sample of 480 individuals from 74 Aust/NZ pre-eclampsia families (including the original 34 genome-scanned families). Our best associations between ACVR2A polymorphisms and pre-eclampsia were for rs10497025 (P = 0.025), rs13430086 (P = 0.010) and three novel SNPs: LF004, LF013 and LF020 (all with P = 0.018). After correction for multiple hypothesis testing, none of these associations reached significance (P > 0.05). Based on these data, it remains unclear what role, if any, ACVR2A polymorphisms play in pre-eclampsia risk, at least in these Australian families. However, it would be premature to rule out this gene as significant associations between ACVR2A SNPs and pre-eclampsia have recently been reported in a large Norwegian (HUNT) population sample.

Reversal of hindbrain herniation after maternal-fetal surgery for myelomeningocele subsequently impacts on brain stem function

The aim of our study was to delineate whether the reversal of hindbrain herniation (HH) following fetal myelomeningocele (fMMC) closure subsequently reduces the incidence and severity of HH-associated brainstem dysfunction (BSD). Prior to the NIH-sponsored Management of Myelomeningocele Study (MOMS) trial, 54 children underwent fMMC closure at our institution. Forty-eight (89%) families participated in a structured survey focusing on HH-associated BSD (e.g., apnea, neurogenic dysphagia [ND], gastro-esophageal reflux disease [GERD], neuro-ophthalmologic disturbances [NOD]). Median age at follow-up was 72 months (range: 46-98). Fifty-percent required shunting. HH-related symptoms were completely absent in 15 (63%) non-shunted and 10 (42%) shunted children (P=0.15). No HH-related death occurred and none developed severe persistent cyanotic apnea. ND was reported in 2 (8%) non-shunted and 9 (38%) shunted infants (P=0.03). Mild GERD (medically managed) developed in 2 (8%) without and 6 (25%) with shunt placement (P=0.24). NOD was found in 6 (25%) and 13 (54%) of non-shunted and shunted children, respectively (P=0.07). The majority of fMMC children developed no or only mild BSD at follow-up. Our data support the hypothesis that neurodevelopmental deficits associated with MMC are at least partially acquired and that reversal of HH following fMMC surgery may help to reduce the incidence and severity of BSD.

Intradural inclusion cysts following in utero closure of myelomeningocele: clinical implications and follow-up findings

OBJECT

The goal in this study was to evaluate the incidence and clinical implications of the development of cutaneously derived intradural inclusion cysts (ICs) following fetal myelomeningocele (fMMC) closure.

METHODS

Retrospective databases and responses to a parental questionnaire were reviewed to determine the incidence, clinical presentation, and outcomes of fMMCs in children in whom ICs developed at follow-up.

RESULTS

Prior to the National Institutes of Health (NIH)-sponsored Management of Myelomeningocele Study (MOMS), 54 patients underwent fMMC closure at the authors' institution. Sixteen (30%) presented with symptomatic tethered cord syndrome (TCS) at a median age of 27 months (range 4-93 months). Ten (63%) of the 16 (19% of the total) developed TCS in association with an intradural IC. In 9 (90%) of 10 patients, the IC was seen on preoperative MR imaging, and in 1 it was found during surgery. Four additional children (7% of the total) with evidence of an IC on surveillance MR imaging are currently asymptomatic at 94, 84, 60, and 60 months of age, respectively. All but 1 (an L-3 level lesion) IC developed in infants with L-4 and L-5 defects. After cyst removal, 6 children are asymptomatic at a median follow-up of 36 months (range 12-63 months). Following IC removal, 4 children lost normal bladder function and now require clean intermittent catheterization, and 1 lost normal leg function and now requires a walking aid for ambulation. Histologically, 8 lesions were dermoid, 1 was an epidermoid, and 1 was a mixed dermoid-epidermoid IC. Three patients developed another IC and required its removal at 24, 39, and 51 months, respectively. One required another tethered cord release within 57 months after IC removal.

CONCLUSIONS

Cutaneously derived intradural ICs can develop following fMMC surgery. Deterioration of bladder function, risk of recurrence, and loss of lower-extremity function appear to be the most important long-term complications of IC in children with fMMCs. The ongoing NIH-sponsored MOMS may help determine whether children with fMMC are at increased risk of IC development compared with children treated with postnatal MMC closure. Parents seeking fMMC closure should be informed about the possibility of IC formation and the potential clinical consequences.