Second-trimester intra-abdominal bowel dilation in fetuses with gastroschisis predicts neonatal bowel atresia.

OBJECTIVE: To determine in fetuses with gastroschisis the association between intra-abdominal bowel dilation in the second trimester and neonatal bowel atresia. METHODS: We reviewed ultrasound and medical records of fetuses with gastroschisis from January 1998 to August 2004. Fetuses with intra-abdominal bowel dilation in the second trimester were identified and followed into the neonatal period. RESULTS: We identified 58 mother-infant pairs showing fetal gastroschisis, with at least one prenatal ultrasound at our hospital and which were delivered there, or were transported there as newborns. Forty-eight of the 58 fetuses had no intra-abdominal bowel dilation and none of these neonates had bowel atresia. Ten of the 58 fetuses had intra-abdominal bowel dilation and all had bowel atresia at birth (P<0.0001). In eight cases in which ultrasound was performed at <25 weeks' gestation, intra-abdominal bowel dilation was already present. CONCLUSION: Intra-abdominal bowel dilation in the second trimester predicts neonatal bowel atresia in fetuses with gastroschisis.

Upper level of the spina bifida defect: how good are we?

OBJECTIVE: To assess the accuracy of obstetric sonography in determining the upper level of myelomeningocele lesions. METHODS: This was a retrospective study of 171 consecutive cases of spina bifida repaired in utero. The upper level of the lesion as determined by obstetric sonography was assigned by community physicians prior to referral in the second trimester and by the authors at Vanderbilt University Medical Center during preoperative evaluation. One hundred and eleven cases had levels established by plane-film X-ray or magnetic resonance imaging after delivery and this was regarded as the gold standard. RESULTS: Of the 171 community examinations, only 29% identified a specific upper level of the lesion; our corresponding examinations specified the lesion level in all cases. Of the 111 cases that had upper levels of the lesion established by post-delivery imaging, corresponding levels were available for comparison from 35 of the community examinations and from 111 of the examinations performed at Vanderbilt. All three assigned levels were available for comparison in 35 cases. In 26% of cases, community-assigned levels agreed exactly with post-delivery levels, while 66% agreed within one level and 80% agreed within two levels. In 38% of cases, levels assigned at Vanderbilt agreed exactly with post-delivery levels, while 78% agreed within one level and 96% agreed within two levels. Upper levels of the lesion assigned at Vanderbilt were significantly more accurate overall compared with those assigned by community physicians (signed rank test [paired comparison], P = 0.048). However, comparison of lesion levels assigned at Vanderbilt in the first 50 vs. the last 61 cases revealed a significant learning effect (Fisher's exact test, P = 0.03). When comparison of lesion levels assigned by community physicians was restricted to the first 50 cases at Vanderbilt, accuracy was similar (n = 13; t-test, P = 0.16; rank sum test, 0.31). CONCLUSIONS: Community physicians were successful in assigning the upper level of the spina bifida lesion only 29% of the time. When successful, the accuracy of these determinations was similar to that of the authors at Vanderbilt. A significant learning effect was demonstrated by improved accuracy over time at Vanderbilt. A concerted continuing medical education effort is indicated to improve the imaging skills of physicians in the accurate diagnosis of the severity of spina bifida in fetuses.

Intrauterine myelomeningocele repair: effect on short-term complications of prematurity.

OBJECTIVE: To determine whether short-term complications of prematurity are affected by intrauterine myelomeningocele repair. METHODS: Medical records of the first 100 infants undergoing intrauterine myelomeningocele repair (IUMR) at the Vanderbilt University Medical Center were reviewed. Infants born at <34 weeks' gestation were identified. Two controls were identified for each IUMR infant. Controls were matched for gestational age, sex, birth weight, antenatal steroids, and mode and month of delivery. Development of respiratory distress syndrome, intraventricular hemorrhage, and chronic lung disease and days on ventilator and length of hospital stay were recorded. The results are expressed as mean values and ranges. Comparison of data between groups was performed using the Mann-Whitney U test. Categorical data were compared using the chi-square test and Fisher's exact test. p

Gestational age at intrauterine myelomeningocele repair does not influence the risk of prematurity.

OBJECTIVE: To determine the effect of gestational age at the time of intrauterine myelomeningocele repair on the duration of pregnancy and the gestational age at the time of delivery. METHODS: This study is a retrospective chart review of the maternal and neonatal medical records of all infants undergoing intrauterine myelomeningocele repair at Vanderbilt University Medical Center. Birth weight, gestational age at the time of surgery and gestational age at the time of delivery were recorded. Infants were divided into 2 groups depending on gestational age at the time of surgery, either > or = 25 weeks' gestation (group 1) or < 25 weeks (group 2). Results were expressed as medians and interquartile ranges. Statistical analysis was done using the unpaired (2-sample) t test; p values < or = 0.05 were considered significant. RESULTS: Ninety-five infants were studied. Fifty-one infants were repaired after 25 weeks' gestation (group 1) at a median gestational age of 26.3 weeks (range 25.6-27.6). Their median gestational age at delivery was 34.4 weeks (range 32.6-35.3). Forty-four infants were repaired before 25 weeks' gestation (group 2). Surgery was done at a median gestational age of 23.6 weeks (range 22.4-24.5). The median gestational age at delivery was 34 weeks (range 31.6-35.3; p = 0.88). CONCLUSION: Early intrauterine myelomeningocele repair before 25 week's gestation does not decrease the gestational age at delivery when compared with repair after 25 weeks.

Percutaneous laser ablation of fetal congenital cystic adenomatoid malformation: too little, too late?

OBJECTIVE: Congenital cystic adenomatoid malformation, type III (CCAM III) lesions are large, bulky tumors which can cause mediastinal shift, prevent normal pulmonary growth, and compress the esophagus, thus leading to complications of nonimmune hydrops, pulmonary hypoplasia and polyhydramnios. Because the mortality rate of untreated fetuses with CCAM and hydrops is high, early delivery or intrauterine resection of the enlarged pulmonary lobe (lobectomy) is indicated; however, open fetal resection of CCAM at less than 30 weeks is associated with perioperative mortality that approaches 40%, as well as the usual maternal and fetal morbidity of open fetal surgery. As an alternative, percutaneous laser ablation of a CCAM III lesion with hydrops was attempted. METHODS: A 30-year-old G3 P1011 with CCAM III in the left fetal hemithorax developed mediastinal shift, hydrops and polyhydramnios at 23 weeks' gestation. After pregnancy termination and open fetal resection were declined, an 18-gauge needle was placed into the fetal tumor percutaneously under real-time ultrasonographic guidance, using sterile technique with light sedation. A cleaved 400-microm Nd:YAG laser fiber was passed through the needle lumen, and using a power setting of 15 W, a total of 2,943 J of laser energy was delivered in pulses of 1.0 s at 0.2-second intervals over two sessions one week apart. RESULTS: Although tumor size decreased, the hydrops worsened and fetal death occurred. CONCLUSIONS: The fetus with CCAM complicated by hydrops is already so compromised by the advanced state of the disease that insufficient time is available for necrotic tissue reabsorption after minimally invasive therapy with laser energy. Until earlier markers for intervention are determined, percutaneous laser debulking of CCAM is unlikely to be successful.

Management of shoulder dystocia.

OBJECTIVE: We sought to determine the management of shoulder dystocia currently practiced by physicians in the Middle Tennessee region and the frequency of use of the all-fours (Gaskin) maneuver in clinical practice. METHODS: A questionnaire was developed and sent to physicians in the Middle Tennessee area, asking how they would manage shoulder dystocia in specific practice scenarios. RESULTS: The methods most commonly used to manage shoulder dystocia are episiotomy, the McRoberts maneuver, and suprapubic pressure. Twenty-four percent of practitioners listed more than four options for the management of shoulder dystocia. Only 8% of those surveyed claimed knowledge of and use of the all-fours maneuver. CONCLUSION: Educational programs should be developed to inform practitioners of additional options for the management of shoulder dystocia.

Umbilical artery Doppler velocimetry in pregnancies complicated by oligohydramnios.

OBJECTIVE: To determine the role of umbilical artery Doppler velocimetry in the management of oligohydramnios. STUDY DESIGN: In a retrospective chart review covering a two-year period, pregnancies with oligohydramnios evaluated by Doppler velocimetry of the umbilical artery were identified. Those patients with ruptured membranes and complex congenital anomalies were excluded from analysis. In the remainder, various measures of perinatal morbidity, including delivery of a small-for-gestational-age infant, preterm delivery, hyperbilirubinemia, requirement for blood transfusion, and other cardiovascular or pulmonary complications, were correlated with recorded values of the systolic/diastolic (S/D) ratio. RESULTS: Seventy-six subjects were identified for study. Forty-six had normal S/D ratios; 17 (37%) were associated with identifiable perinatal morbidity. When prematurity due to delivery for the sole indication of oligohydramnios was excluded, morbidity occurred in five patients (11%). Conversely, of the 30 patients with abnormal Doppler indices, 80% had an adverse outcome. CONCLUSION: Pregnancies with oligohydramnios and normal umbilical artery Doppler velocimetry were significantly (P < .001) less likely to experience an abnormal perinatal outcome as compared to those with abnormal Doppler indices. An elevated S/D ratio identified an increased risk of an adverse perinatal outcome in women with oligohydramnios. Avoiding intervention in pregnancies with oligohydramnios and normal umbilical artery Doppler velocimetry may decrease iatrogenic morbidity due to prematurity by as much as 26%.

Fetal MRI in the evaluation of intrauterine myelomeningocele.

BACKGROUND: Accurate fetal imaging is essential to the practice of maternal-fetal medicine. While ultrasonography has been the traditional mainstay of fetal imaging, its ability to resolve critical features of central nervous system (CNS) anatomy remains limited. As interest in intrauterine therapy for myelomeningocele has increased, so has the need for more accurate, noninvasive imaging of the CNS. Fetal magnetic resonance imaging (MRI) promises to fill the gap left by ultrasound. METHODS: Thirty-seven MRI scans of fetuses previously diagnosed with myelomeningocele were reviewed by 2 neuroradiologists. The ability of fetal MRI to resolve the commonest CNS stigmata of spina bifida, and the incidence and extent of interobserver error, was assessed. In 4 cases, postnatal MRIs were also available. These were compared to the corresponding fetal studies. RESULTS: The imaging quality with the technique used in this study was excellent, even without the use of maternal or fetal sedation. There were no complications, and the imaging times were minimal. Interobserver error was minimal with respect to the evaluation of ventricular dilatation and hindbrain herniation, but moderate in the description and location of the spinal lesion. As had previously been documented with ultrasonography, a reduction was seen in hindbrain herniation when comparing pre- and postnatal MRIs. CONCLUSION: It is concluded that fetal MRI is an effective, noninvasive means of assessing fetal CNS anatomy. Its ability to resolve posterior fossa anatomy is superior to ultrasonography while, with respect to the evaluation of hydrocephalus and the level and nature of the spinal lesion, it may be equivalent to inferior. Inclusion of the fetal MRI into the standard diagnostic armamentarium will probably await the next major advance in speed and resolution. It is conceivable that, with further advances, MRI might supplant ultrasonography as the diagnostic tool of choice for evaluation of fetal anomalies including myelomeningocele.

Use of bipedicular advancement flaps for intrauterine closure of myeloschisis.

Several groups have begun to explore the feasibility and utility of intrauterine closure of myelomeningocele. A subset of these fetuses have defects which fall into the category of myeloschisis, and therefore have inadequate skin to enable primary closure. After considerable discussion, it was decided to utilize bipedicular flaps to close these lesions. The procedure is described, and representative examples are shown. To date, 13 of 56 fetuses have required this approach for closure in utero. While this technique generally provides adequate coverage of the dural sac, the cosmetic results have been less than optimal.

In utero repair of myelomeningocele: a comparison of endoscopy and hysterotomy.

OBJECTIVE: To compare endoscopic coverage of myelomeningocele with a maternal split-thickness skin graft in utero to definitive neurosurgical closure through a hysterotomy. METHODS: Four fetuses with isolated myelomeningocele underwent endoscopic coverage of the defect with a maternal split-thickness skin graft in a CO(2) environment at 22-24 weeks' gestation. Subsequently, 4 fetuses underwent standard neurosurgical closure of their myelomeningoceles at 28-29 weeks' gestation. RESULTS: The mean operating time for the endoscopic procedures was 297 +/- 69 min. Two fetal losses occurred as a result of chorioamnionitis and placental abruption, respectively. A third baby delivered at 28 weeks' gestation after prolonged disruption of the membranes. The 2 survivors required standard closure of the myelomeningocele after delivery. The mean operating time for the hysterotomy procedures was 125 +/- 8 min. No mortality occurred, and all the infants delivered between 33 and 36 weeks with well-healed myelomeningocele scars. At present, the functional levels of all infants approximate the anatomical levels of the lesions. CONCLUSION: With current technology, in utero repair of congenital myelomeningocele through a hysterotomy appears to be technically superior to procedures performed endoscopically.

The Tulipan-Bruner trocar for uterine entry during fetal surgery.

OBJECTIVE: Our goal was to compare the use of a specially designed trocar for initial uterine entry with standard entry by electrocautery in creation of a hysterotomy for fetal surgery. STUDY DESIGN: Ten consecutive patients undergoing hysterotomy for intrauterine repair of myelomeningocele were randomized to initial uterine entry with electrocautery or with the Tulipan-Bruner trocar. Timing of initial uterine entry with electrocautery began with incision into the uterine serosa and ended with incision of the chorioamnionic membranes. Timing of initial uterine entry with the Tulipan-Bruner trocar began with placement of stay sutures and ended with removal of the central introducer from the peel-away sheath. Blood loss was estimated by the primary surgeon. All of the participating surgeons judged the convenience and ease of each technique. The times required for initial uterine entry were compared with an unpaired t test. Statistical significance was set at P <.05. RESULTS: The time required for initial uterine entry with electrocautery was 231 +/- 63 (mean +/- SD) seconds compared with 146 +/- 51 seconds with the trocar (P <.05). The total blood loss for all 10 cases was <50 mL, but the presence of blood in the wound was judged much more inconvenient when electrocautery was used. Finally, electrocautery required 2 surgical assistants in every case, whereas the trocar was readily placed with only a single assistant. CONCLUSION: The Tulipan-Bruner trocar provides quicker, less traumatic uterine entry during creation of a hysterotomy, as compared with electrocautery.

Fetal surgery for myelomeningocele and the incidence of shunt-dependent hydrocephalus.

CONTEXT: Intrauterine closure of exposed spinal cord tissue prevents secondary neurologic injury in animals with a surgically created spinal defect; however, whether in utero repair of myelomeningocele improves neurologic outcome in infants with spina bifida is not known. OBJECTIVE: To determine whether intrauterine repair of myelomeningocele improves patient outcomes compared with standard care. DESIGN: Single-institution, nonrandomized observational study conducted between January 1990 and February 1999. SETTING: Tertiary care medical center. PARTICIPANTS: A sample of 29 study patients with isolated fetal myelomeningocele referred for intrauterine repair that was performed between 24 and 30 gestational weeks and 23 controls matched to cases for diagnosis, level of lesion, practice parameters, and calendar time. All infants were followed up for a minimum of 6 months after delivery. MAIN OUTCOME MEASURES: Requirement for ventriculoperitoneal shunt placement, obstetrical complications, gestational age at delivery, and birth weight for study vs control subjects. RESULTS: The requirement for ventriculoperitoneal shunt placement for decompression of hydrocephalus was significantly decreased among study infants (59% vs 91%; P = .01). The median age at shunt placement was also older among study infants (50 vs 5 days; P = .006). This may be explained by the reduced incidence of hindbrain herniation among study infants (38% vs 95%; P<.001). Following hysterotomy, study patients had an increased risk of oligohydramnios (48% vs 4%; P = .001) and admission to the hospital for preterm uterine contractions (50% vs 9%; P = .002). The estimated gestational age at delivery was earlier for study patients (33.2 vs 37.0 weeks; P<.001), and the birth weight of study neonates was less (2171 vs 3075 g; P<.001). CONCLUSIONS: Our study suggests that intrauterine repair of myelomeningocele decreases the incidence of hindbrain herniation and shunt-dependent hydrocephalus in infants with spina bifida, but increases the incidence of premature delivery.

Sectio parva for fetal preservation.

Selective abdominal delivery, or sectio parva, is cesarean delivery of one of multiple fetuses, but not the other(s). Eleven cases have been reported for the purpose of aborting one twin, and this is the second report of an attempt to improve the outcome of both twins. Perinatal outcomes have ranged from almost immediate delivery of the second twin because of placental abruption, to elective delivery of the survivor at term.

Prenatal diagnosis of Down's syndrome in the presence of isolated Ebstein's anomaly.

Ebstein's anomaly is a rare congenital cardiac defect, characterized by the displacement of the tricuspid valve into the right ventricle, that occurs approximately once in 20,000 live births. The association of Ebstein's anomaly and chromosomal abnormalities, such as Down's syndrome, is extremely unusual. Prenatal diagnosis of trisomy 21 in a fetus with isolated Ebstein's anomaly has not been previously reported.

Equalization of amniotic fluid volumes after decompression amniocentesis for treatment of the twin oligohydramnios-polyhydramnios sequence.

OBJECTIVE: To measure acute and chronic changes in the placenta and amniotic fluid associated with performance of decompression amniocentesis in pregnancies with the twin oligohydramnios-polyhydramnios sequence (TOPS). METHODS: Amniotic fluid pressures, placental thickness, placental perfusion, and amniotic fluid volumes were measured in each sac of a monochorionic diamniotic twin gestation before and after decompression amniocentesis. Indigo carmine was injected into the polyhydramnic sac after decompression, and fluid from the oligohydramnic sac was sampled after equilibration. Spectrophotometric analysis of amniotic fluid specimens was performed for dye detection. Amniotic fluid volume and placental perfusion studies were repeated 1 week later. RESULTS: Three patients with TOPS were enrolled, and decompression amniocentesis was performed in the midtrimester. After decompression, amniotic fluid volume decreased in the polyhydramnic sac, amniotic fluid pressures decreased in both sacs, placental thickness increased, and umbilical artery Doppler velocimetry was unaffected. The amniotic fluid volume increased acutely in only one oligohydramnic sac after decompression, and ultrasonographic examination, amniotic fluid spectrophotometric analysis, and placental pathologic examination all identified interfetal membrane disruption as the etiology. CONCLUSIONS: Decompression amniocentesis as a treatment for TOPS does not result in acute or chronic changes in the amniotic fluid volume of the oligohydramnic sac in the absence of interfetal membrane disruption.

Endoscopic coverage of fetal myelomeningocele in utero.

OBJECTIVE: Our goal was to evaluate the safety and efficacy of minimally invasive surgery for the coverage of myelomeningocele in utero. STUDY DESIGN: Women in the mid-second trimester of a pregnancy complicated by fetal myelomeningocele were offered an experimental procedure designed to prevent ongoing exposure of the spinal cord to the intrauterine environment. The procedure consisted of maternal laparotomy while the patient was under both general and epidural anesthesia, with exposure of the gravid uterus. Endoscopic ports were placed for camera and operating instruments. Amniotic fluid was removed and replaced with carbon dioxide. The fetus was then positioned and a maternal split-thickness skin graft was placed over the exposed spinal cord or neural elements. The skin graft and a covering of Surgicel Absorbable Hemostat were attached with fibrin glue prepared from autologous cryoprecipitate. RESULTS: Four fetuses with open myelomeningocele underwent endoscopic coverage of the spinal lesion between 22 weeks 3 days and 24 weeks 3 days of gestation. One infant, delivered by planned cesarean section at 35 weeks' gestation after demonstration of fetal lung maturity, is almost 3 years old. A second infant was delivered by cesarean section at 28 weeks after preterm labor and is now almost 6 months old. Both survivors manifest only mild motor and somatosensory deficits. One fetus who was delivered 1 week after operation after development of amnionitis died in the delivery room of extreme prematurity. The final fetus died intraoperatively from abruptio placentae. CONCLUSION: Minimally invasive fetal surgery appears to constitute a feasible approach to nonlethal fetal malformations that result in progressive and disabling organ damage.

Effect of intrauterine myelomeningocele repair on central nervous system structure and function.

BACKGROUND: It has been postulated that intrauterine myelomeningocele repair might improve neurologic outcome in patients with myelomeningocele. A total of 59 such procedures have been performed at Vanderbilt University. Preliminary results suggested that the degree of hindbrain herniation is reduced by intrauterine repair. In an attempt to further quantify the possible benefits of this surgery, a subset of these patients was brought back to Vanderbilt for study. METHODS: A group of 26 patients who had undergone intrauterine myelomeningocele repair underwent an extensive evaluation which included manual muscle testing, MR imaging and precise determination of the anatomic level of their lesions as well as multiple other tests. The results of this analysis were compared to those in 2 groups of historical controls. RESULTS: In this group of patients intrauterine myelomeningocele repair substantially reduced the incidence of moderate to severe hindbrain herniation (4 vs. 50%). The incidence of shunt-dependent hydrocephalus was more modestly reduced (58 vs. 92%). The average level of leg function closely matched the average anatomic level of the lesion in both the fetal surgery and control groups. CONCLUSION: The most dramatic effect of intrauterine repair appears to be on hindbrain herniation. A less dramatic, but significant, reduction in shunt-dependent hydrocephalus is also seen. Prospective patients should be cautioned not to expect improvement in leg function as the result of this surgery. The potential benefits of surgery must be carefully weighed against the potential risks of prematurity.

Intrauterine myelomeningocele repair reverses preexisting hindbrain herniation.

BACKGROUND: It has been reported that intrauterine myelomeningocele repair reduces the amount of hindbrain herniation normally seen in association with the Chiari type II malformation. It is not yet known, however, whether hindbrain herniation is prevented, or whether preexisting herniation is reversed. The following study was designed to elucidate this issue. METHODS: A series of 9 patients underwent intraoperative ultrasound examinations immediately prior to intrauterine myelomeningocele repair. These same patients were then evaluated postnatally using ultrasound and/or MRI. The degree of hindbrain herniation before and after repair was compared using a grading system devised by the authors. RESULTS: Eight patients had clear evidence of moderate to severe hindbrain herniation on intraoperative scans while one was mild. In contrast, on postnatal studies 5 of 9 patients had no evidence of hindbrain herniation, while the other 4 had only mild herniation. CONCLUSION: Intra-uterine myelomeningocele repair appears to reverse preexisting hindbrain herniation. It is postulated that continuous flow of cerebrospinal fluid through the neural placode is the force responsible for inducing migration of the cerebellum and brain stem downward through the foramen magnum. By interrupting that flow during gestation, intrauterine myelomeningocele repair enables the cerebellum and brain stem to resume a normal, or nearly normal, configuration.