Fetal Endoscopic Third Ventriculostomy Is Technically Feasible in Prenatally Induced Hydrocephalus Ovine Model.

BACKGROUND: Congenital obstructive hydrocephalus generates progressive irreversible fetal brain damage by ventricular enlargement and incremental brain tissue compression that leads to maldevelopment and poor clinical outcomes. Intrauterine treatments such as ventriculo-amniotic shunting have been unsuccessfully tried in the eighties. OBJECTIVE: To assess if prenatal endoscopic third ventriculostomy (ETV) is feasible in a large animal model and optimize this technique for ventricular decompression and potential arrest of fetal brain damage in fetal lambs. METHODS: We generated hydrocephalus in 50 fetal lambs by injecting a polymeric agent into the cisterna magna at midgestation (E85). Subsequently, 3 weeks later (E105), fetal ETV was performed using a small rigid fetoscope. The endoscopy entry point was located anterior to the coronal suture, 7 mm from the midline. RESULTS: We obtained clear visualization of the enlarged lateral ventricles by endoscopy in the hydrocephalic fetal lambs. The floor of the third ventricle was bluntly perforated and passed with the scope for a successful ETV. Total success was achieved in 32/50 cases (64%). Causes of failure were blurred vision or third ventricle obliteration by BioGlue in 10/50 (20%) cases, anatomic misdirection of the endoscope in 5 (10%) cases, 2 cases of very narrow foramen of Monro, and 1 case of choroid plexus bleeding. If we exclude the cases artificially blocked by the polymer, we had a successful performance of prenatal-ETV in 80% (32/40) of hydrocephalic fetuses. CONCLUSION: Despite the inherent difficulties arising from ovine brain anatomy, this study shows that innovative fetal ETV is technically feasible in hydrocephalic fetal lambs.

Intracisternal BioGlue injection in the fetal lamb: a novel model for creation of obstructive congenital hydrocephalus without additional chemically induced neuroinflammation.

OBJECTIVE: The authors hypothesized that new agents such as BioGlue would be as efficacious as kaolin in the induction of hydrocephalus in fetal sheep. METHODS: This study was performed in 34 fetal lambs randomly divided into 2 studies. In the first study, fetuses received kaolin, BioGlue (2.0 mL), or Onyx injected into the cisterna magna, or no injection (control group) between E85 and E90. In the second study, fetuses received 2.0-mL or 2.5-mL injections of BioGlue into the cisterna magna between E85 and E90. Fetuses were monitored using ultrasound to assess lateral ventricle size and progression of hydrocephalus. The fetuses were delivered (E120-E125) and euthanized for histological analysis. Selected brain sections were stained for ionized calcium binding adaptor 1 (Iba1) and glial fibrillary acidic protein (GFAP) to assess the presence and activation of microglia and astroglia, respectively. Statistical comparisons were performed with Student's t-test for 2 determinations and ANOVA 1-way and 2-way repeated measures for multiple determinations. RESULTS: At 30 days after injection, the lateral ventricles were larger in all 3 groups that had undergone injection than in controls (mean diameter in controls 3.76 ± 0.05 mm, n = 5). However, dilatation was greater in the fetuses injected with 2 mL of BioGlue (11.34 ± 4.76 mm, n = 11) than in those injected with kaolin (6.4 ± 0.98 mm, n = 7) or Onyx (5.7 ± 0.31 mm, n = 6) (ANOVA, *p ≤ 0.0001). Fetuses injected with 2.0 mL or 2.5 mL of BioGlue showed the same ventricle dilatation but it appeared earlier (at 10 days postinjection) in those injected with 2.5 mL. The critical threshold of ventricle dilatation was 0.1 for all the groups, and only the BioGlue 2.0 mL and BioGlue 2.5 mL groups exceeded this critical value (at 30 days and 18 days after injection, respectively) (ANOVA, *p ≤ 0.0001). Moderate to severe hydrocephalus with corpus callosum disruption was observed in all experimental groups. All experimental groups showed ventriculomegaly with significant microgliosis and astrogliosis in the subventricular zone around the lateral ventricles. Only kaolin resulted in significant microgliosis in the fourth ventricle area (ANOVA, *p ≤ 0.005). CONCLUSIONS: The results of these studies demonstrate that BioGlue is more effective than Onyx or kaolin for inducing hydrocephalus in the fetal lamb and results in a volume-related response by obstructive space-occupancy without local neuroinflammatory reaction. This novel use of BioGlue generates a model with potential for new insights into hydrocephalus pathology and the development of therapeutics in obstructive hydrocephalus. In addition, this model allows for the study of acute and chronic obstructive hydrocephalus by using different BioGlue volumes for intracisternal injection.

CD200-CD200R imbalance correlates with microglia and pro-inflammatory activation in rat spinal cords exposed to amniotic fluid in retinoic acid-induced spina bifida.

Spina bifida aperta is a congenital malformation characterized by the failure of neural tube closure resulting in an unprotected fetal spinal cord. The spinal cord then undergoes progressive damage, likely due to chemical and mechanical factors related to exposure to the intrauterine environment. Astrogliosis in exposed spinal cords has been described in animal models of spina bifida during embryonic life but its relationship with neuroinflammatory processes are completely unknown. Using a retinoic acid-induced rat model of spina bifida we demonstrated that, when exposed to amniotic fluid, fetal spinal cords showed progressive astrogliosis with neuronal loss at mid-gestation (E15) compared to unexposed spinal cords. The number of microglial cells with a reactive phenotype and activation marker expression increased during gestation and exhibited progressive disruption in the inhibitory immune ligand-receptor system. Specifically we demonstrate down-regulation of CD200 expression and up-regulation of CD200R. Exposed spinal cords demonstrated neuroinflammation with increased tissue water content and cytokine production by the end of gestation (E20), which correlated with active Caspase3 expression in the exposed layers. Our findings provide new evidence that microglia activation, including the disruption of the endogenous inhibitory system (CD200-CD200R), may participate in the pathogenesis of spina bifida through late gestation.

Maldevelopment of the cerebral cortex in the surgically induced model of myelomeningocele: implications for fetal neurosurgery.

PURPOSE: The purpose of this study is to describe the malformations of cortical development detected in a model of cerebrospinal fluid (CSF) leakage and the influence of surgical closure technique on developmental outcome. METHODS: Using a surgically induced model of myelomeningocele (MMC) in sheep, we studied the effects of different repair methods upon the development of hydrocephalus, the presence of the Arnold-Chiari II (AC-II) hindbrain malformation, and cerebral cortex developmental anomalies using gross and histologic (hematoxylin and eosin and Nissl staining) study techniques. RESULTS: A malformed cerebral cortex, including 2 anomalous cortical folding patterns, and lower brain weights were observed in the untreated animals. Hydrocephalus and AC-II malformations were also found in this group. These malformations were mostly prevented with prenatal 2-layer closure. CONCLUSIONS: Cerebral cortical malformations and hydrocephalus, in addition to the AC-II hindbrain malformation, are disorders caused by fetal CSF leakage. These malformations were prevented with the technique of MMC closure currently used in humans. Both observations magnify the importance of the second hit associated with chronic CSF leakage, in addition to the primary defect causing the MMC, in the development of the malformation complex.

Graft-vs-host disease after small bowel transplantation in children.

PURPOSE: Graft-vs-host disease (GVHD) is a rare complication of transplantation of organs rich in immunocompetent cells. The goal of this study was to report the features of GVHD after small bowel transplantation (SBTx) in children. METHODS: The study involved a retrospective review of patients undergoing SBTx between 1999 and 2009 who had GVHD. RESULTS: Of 46 children receiving 52 intestinal grafts (2 liver-intestine and 3 multivisceral), 5 (10%) developed GVHD. Median age at transplant was 42 (19-204) months. Baseline immunosupression consisted of tacrolimus and steroids supplemented with thymoglobulin (n = 2) or basiliximab (n = 3) for induction. Median time between transplantation and GVHD was 47 (16-333) days. All patients had generalized rash, 2 had diarrhea, and 2 had respiratory symptoms. Other symptoms were glomerulonephritis (n = 1) and conjunctivitis (n = 1). Four developed severe hematologic disorders. The diagnosis was confirmed by skin biopsy in 4 patients and supported by chimerism studies in two. Colonoscopy and opthalmoscopic findings were also suggestive in one. Treatment consisted of steroids and decrease of tacrolimus, with partial response in four. Other immunosuppressants were used in refractory or recurrent cases. Three patients died within 4 months after diagnosis. CONCLUSION: Graft-vs-host disease is a devastating complication of SBTx, with high mortality probably associated with severe immunologic dysregulation.

Pediatric surgeons and gastroesophageal reflux.

BACKGROUND/AIMS: Better antacid medications and the introduction of laparoscopy destabilize the indications for fundoplication. This study aims at raising a discussion among pediatric surgeons on these indications, modalities, and the results of this operation. MATERIALS AND METHODS: A total of 252 refluxing children operated between 1992 and 2006 were divided into groups according to predominant symptoms (93 digestive, 47 respiratory, and 68 neurologic) or to comorbidities (27 esophageal atresia, 10 diaphragmatic hernia, 5 abdominal wall defects, and 2 caustic stricture), and the indications, complications, mortality, and long-term results were reviewed. Features of open (n = 135) and laparoscopic (n = 117) approaches were compared, and long-term integrity of the wrap was analyzed using the Kaplan-Meier method. RESULTS: Digestive, respiratory, and neurologic patients had more often laparoscopic plications, whereas all others rather had an open approach. The rate of complications was 22%, and they were more frequent in children operated by laparotomy (P < .05). Median follow up was 51.3 months (range, 6-160). Overall wrap integrity was maintained in 89% of the children, and the proportions for digestive, respiratory, and neurologic groups were 95%, 95%, and 87%, respectively. For esophageal atresia, congenital diaphragmatic hernia, abdominal wall defects, and caustic stricture, they were 72%, 77%, 100%, and 0%, respectively. The functional results were fully satisfactory in 83% of patients. There were 17 deaths (6.7%), but only 3 in the first postoperative month and only 1 related to the operation (0.4%). CONCLUSIONS: Fundoplication is a powerful method of reflux control. It is indicated after failure of medical treatment in gastroesophageal reflux disease and in symptomatic refluxers with some particular comorbidities. Surgery should be offered only after diagnosis has been firmly established, and the indications must remain identical for open and laparoscopic procedures. High technical standards and rigorous report of the results are required for keeping a relevant place of pediatric surgery in the treatment of this disease.

Teratomas of the neck and mediastinum in children.

This retrospective study reviews a series of teratomas of the neck and mediastinum aiming at defining the features of these particular locations. We recorded prenatal diagnosis, perinatal management, clinical and radiologic features, pathology, surgical strategies and results in cervical and mediastinal teratomas treated over the last 10 years. During this period we treated 66 children with teratoma of which 11 (6 male and 5 female) had cervicomediastinal locations. Five babies had cervical teratomas extended into the anterior mediastinum in two cases. Prenatal diagnosis was made in three (two with polyhydramnios). Four babies were born by C-section and only one had a successful EXIT procedure. The diagnosis was confirmed by imaging and increased AFP. Surgical treatment involved total tumor removal and in one case subsequent removal of lymph node metastases. All children survived except one in whom airway could not be cleared at birth. Two children bear mild hypothyroidism. During the same period six patients aged 0-17 years were treated for mediastinal teratoma. Only one was prenatally diagnosed and only two had some dyspnea. Removal was performed either by median sternotomy, thoracotomy, or thoracoscopy. They all survive and are free of disease. Teratomas of the neck may cause fetal disease and unmanageable neonatal airway obstruction. Prenatal diagnosis and planned multidisciplinary management are mandatory at birth. In contrast, only some mediastinal tumors cause respiratory embarrassment. Although benign, these tumors are sometimes immature and may metastasize to regional lymph nodes. Total surgical removal is curative. Thyroid insufficiency may be present at birth in cervical teratomas and may be aggravated by surgery.

The role of GLUT1 immunostaining in the diagnosis and classification of liver vascular tumors in children.

BACKGROUND/AIM: GLUT1 is an erythrocyte-type glucose transporter protein typically expressed in cutaneous proliferating hemangioma. Immunostaining for GLUT1 is becoming valuable for predicting the outcome of vascular skin tumors. Liver vascular tumors (LVTs) are a serious challenge for pediatric surgeons because of their often severe and sometimes unpredictable clinical course. To improve therapeutic strategies, we designed this study in which we tested in pathology specimens of LVT the hypothesis that GLUT1 expression could be useful to understand and classify LVT. MATERIAL AND METHODS: In the last 10 years, we treated 20 children with LVT. Pathology specimens from biopsy, excision, or autopsy were available in 11 of them. The paraffin sections were immunostained for GLUT1 and also for Ki-67 to assess the proportion of proliferating cells. Patients were divided into 2 groups: GLUT1-positive (n = 4) and GLUT1-negative (n = 7) that were compared for age at diagnosis, survival, and proportion of proliferating cells. Nonparametric and chi 2 tests were used for statistical analysis as appropriate. RESULTS: Mean age at diagnosis was higher in GLUT1-positive group, although not statistically significant in comparison with GLUT1-negative (308 +/- 515 vs 70 +/- 51 days, respectively). Three of 4 children in GLUT1-positive group died versus 1 of 7 in the GLUT1-negative group (not significant). All GLUT1-positive tumors were multicentric hemangiomata without central necrosis and only 1 with large vessels. Among GLUT1-negative tumors, 5 were solitary masses and 2 were multicentric (the value of the last 2 specimens was uncertain), 2 had central necrosis, and 2 had large vessels. Proliferation index was 18% +/- 1.42% and 1.42% +/- 0.97%, respectively, in each group ( P < .05). CONCLUSIONS: GLUT1-positive tumors have significantly higher proliferation rates than negative ones. Mortality tended to be higher in children with GLUT1-positive tumors. Positive GLUT1 immunostaining is likely specific for proliferating hemangioma, and it predicts the typical course of proliferation followed by involution.