Pediatric Surgery remains the only true General Surgery.

This article states that Pediatric Surgery remains probably the only remaining General Surgery because it is not about organs and systems but rather the whole Surgery from fetal life until completion of growth and maturation. Pediatric surgeons are currently involved in prenatal treatments for fetal diseases, they take in charge the surgery of congenital malformations, acquired neonatal diseases, common conditions like hernias, undescended testes and appendicitis, but also of the more complex gastrointestinal, broncho-pulmonary or genitourinary conditions, tumors, trauma and solid organ transplantation. For this, like other surgical specialists, they use open, endoscopic and minimally invasive techniques. The broad spectrum of diseases, many of them scarcely prevalent, makes training long and hard, but this challenge accounts for the greatness of this specialty. Pediatric surgeons also carry out research work in their field because they are aware that understanding of why the conditions treated by them occur is mandatory. In summary, Pediatric Surgery is a lively, exciting, difficult specialty that offers an attractive alternative to young doctors interested in surgery.

European Paediatric Surgeons' Association Survey on the Management of Hirschsprung Disease.

Aim This study aims to define patterns of Hirschsprung disease (HD) management. Methods An online questionnaire was sent to all European Paediatric Surgeons' Association (EUPSA) members. Results A total of 294 members (61 countries) answered (response rate: 61%). DIAGNOSIS: All respondents perform rectal biopsies (61% rectal suction [RSBs], 39% open full-thickness), 96% contrast enema, and 31% anorectal manometry. At RSB, 17% take the most distal biopsy 1 cm above the dentate line, 34% take 2 cm, 30% take 3 cm, and 19% take > 3 cm. Rectal biopsy staining's are hematoxylin/eosin (77%), acetylcholinesterase (74%), calretinin (31%), S100 (2%), nicotinamide adenine dinucleotide-tetrazolium reductase (2%), succinate dehydrogenase (1%), and neuron-specific enolase (1%). A total of 85% respondents recognize entities including hypoganglionosis (69%), intestinal neuronal dysplasia (55%), and ultrashort segment HD (50%). SURGERY: Pull-through (PT) is performed at diagnosis by 33% or delayed by 67% (4 months or > 5 kg). Awaiting definitive surgery, 77% perform rectal irrigations, 22% rectal dilatation/stimulations, and 33% perform a stoma. The preferred type of PT is the Soave approach (65%), performed with transanal technique by 70% respondents. If symptoms persist after PT, most opt for conservative approach (enemas/laxatives = 76%; botulinum toxin = 27%), 30% would redo the PT. Total colonic aganglionosis: PT is performed in neonates (4%), at 1 to 6 months (29%), 6 to 12 months (37%) or older (30%). If required, a stoma is sited in the ileum (31%), according to intraoperative biopsies (54%), macroscopic impression (13%), and radiology (2%). Duhamel PT is performed by 52%, Soave by 31%, and Swenson by 17%. Overall, 31% would perform a J-pouch. Conclusions Most aspects of HD management lack consensus with wide variations in obtaining a diagnosis. Transanal Soave PT is the most common technique in standard segment HD. Guidelines should be developed to avoid such variability in management and to facilitate research studies.

International Survey on the Management of Congenital Diaphragmatic Hernia.

AIM: This study aims to define patterns in the management of congenital diaphragmatic hernia (CDH). METHODS: A total of 180 delegates (77% senior surgeons) from 44 (26 European) countries completed a survey at the 2014 European Pediatric Surgeons' Association meeting. RESULTS: Overall, 34% of the surgeons work in centers that treat < 5 cases of CDH/y, 38% work in centers that treat 5 to 10 cases/y, and 28% work in centers that treat > 10 cases/y. Overall, 62% of the surgeons work in extra corporeal membrane oxygenation (ECMO) centers and 23% in fetal surgery centers. Prenatal work up and delivery: 47% surgeons request prenatal magnetic resonance imaging, 53% offer karyotyping, 22% perform a fetal intervention, 74% monitor head-to-lung ratio, and 55% administer maternal steroids. Delivery is via cesarean section for 47% surgeons, at 36 to 38 weeks for 71% surgeons, and in a tertiary care center for 94% of the surgeons. POSTNATAL MANAGEMENT: A total of 76% surgeons report elective intubation, 65% start antibiotics preoperatively, and 45% administer surfactant. In case of refractory hypoxia, 66% surgeons consider ECMO with a variable course. Parenteral feeding is started preoperatively by 56% of the surgeons. Only 13% of the surgeons request contrast studies preoperatively to rule out malrotation.

Lung maturity in esophageal atresia: Experimental and clinical study.

INTRODUCTION: Esophageal atresia and tracheoesophageal fistula (EA-TEF) survivors suffer respiratory morbidity of unclear pathogenesis. Defective lung morphogenesis has been described in the rat model. This study examined fetal lung growth and maturity in rats and patients with EA-TEF. METHODS: Pregnant rats received either adriamycin or vehicle. Control and adriamycin-exposed lungs, with and without EA-TEF, were weighed and processed for RT-PCR, DNA quantification, immunofluorescence and immunoblot analysis of TTF1, VEGF, Sp-B, and α-sma. Twenty human lungs were also processed for immunofluorescence and Alcian-blue staining. RESULTS: Lungs from fetuses with EA-TEF (E21) showed decreased total DNA; FGF7 and TTF1 mRNA expressions were upregulated at E15 and E18, respectively. Protein expression and immunofluorescent distribution of maturity markers were similar. Lungs from stillborns with EA-TEF showed decreased epithelial expression of Sp-B and VEGF whereas those from newborns tended to have less Sp-B and more VEGF and mucous glands. DISCUSSION: The lungs of rats with EA-TEF were hypoplastic but achieved near-normal maturity. Stillborns with EA-TEF exhibited an apparently disturbed differentiation of the airway epithelium. Newborns with EA-TEF demonstrated subtle differences in the expression of differentiation markers, and increased number of mucous glands that could influence postnatal respiratory adaptation and explain some respiratory symptoms of EA-TEF survivors.

Defective upper gastrointestinal function after repair of combined esophageal and duodenal atresia.

BACKGROUND: Both esophageal atresia (EA) and duodenal atresia (DA) involve deficient anti-reflux barrier, poor esophageal function and eventually, duodenogastric reflux. This study aims at examining the upper gastrointestinal functional status in a cohort of patients with both EA and DA. METHODS: A retrospective survey of patients treated for EA and DA between 1965 and 2012 was conducted. Clinical charts, office visits, imaging, upper gastrointestinal endoscopy and esophageal pH metry/impedance were used to assess the long-term condition of the esophagus, the presence of gastroesophageal reflux disease (GERD) and/or the need for fundoplication. RESULTS: Twenty out of 581 patients treated for EA had associated DA. Ten/twenty children survived; 1 had primary esophageal replacement. With a median follow-up of 9 years, 8/9 had complicated outcomes and 5 still suffered digestive ailments: 2 GER; 1 eosinophilic esophagitis; 1 nodular gastritis, and 1 wrap herniation. A total of 10 procedures were performed: 8 fundoplications, 1 esophagogastric dissociation and 1 replacement with colon. DISCUSSION: The association of EA with DA involves a poor upper digestive function with high risks of GERD and fundoplication failure. The lifelong synergistic play of esophageal, gastric and duodenal dysfunctions in these patients prompts long-term follow-up, and eventually active treatment.

Chylothorax and chylous ascites: management and pitfalls.

Leakage of lymph from the lymphatic ducts causes chylothorax (CT) or chylous ascitis (CA). This may happen for unknown reasons during fetal life or after birth and may also be caused by trauma after thoracic surgery or by other conditions. Fetal CT and CA may be lethal particularly in cases with fetal hydrops that sometimes benefit of intra-uterine instrumentation. After birth, symptoms are related to the amount of accumulated fluid. Sometimes, severe cardio-respiratory compromise prompts active therapy. Most patients with CT or CA benefit from observation, rest, and supportive measures alone. Drainage of the fluid may be necessary, but then loss of protein, fat, and lymphoid cells introduce new risks and require careful replacement. Low-fat diets with MCT and parenteral nutrition decrease fluid production while allowing adequate nutritional input. If lymph leakage does not stop, secretion inhibitors like somatostatin or octreotide are prescribed, although there is only weak evidence of their benefits. Imaging of the lymphatic system is indicated when the leaks persist, but this is technically demanding in children. Shunting of the lymph from one body space to another by means of valved catheters, embolization of the thoracic duct, and/or ligation of the major lymphatics may occasionally be indicated in cases refractory to all other treatments.

Abnormal Sonic hedgehog signaling in the lung of rats with esophageal atresia induced by adriamycin.

BACKGROUND: Abnormal lung development was recently described in the rat model of esophageal atresia and tracheoesophageal fistula (EA-TEF). Since in this condition the ventral-to-dorsal switch of Shh expression in the foregut is disturbed, the present study tested the hypothesis that this abnormal expression at the emergence of the tracheobronchial bud might be translated into the developing lung. METHODS: Pregnant rats received either 1.75 mg/kg i.p. adriamycin or vehicle from E7 to E9. Three groups were studied: control and adriamycin-exposed with and without EA-TEF. Embryos were recovered and the lungs were harvested and processed for reverse transcription polymerase chain reaction and immunofluorescence analysis of the Shh signaling cascade. RESULTS: Shh signaling was downregulated at the late embryonic stage of lung development (E13) in embryos with EA-TEF. Throughout the subsequent stages of development, the expression of both Shh and its downstream components increased significantly and remained upregulated throughout gestation. Immunofluorescent localization was consistent with these findings. CONCLUSION: Defective Shh signaling environment in the foregut is present beyond the emergence of lung buds and probably impairs lung development. Later in gestation, lungs exhibited a remarkable ability to upregulate the Shh cascade, suggesting a compensatory response. These findings may be relevant to understand pulmonary disease suffered by children with EA-TEF.

The multifactorial origin of respiratory morbidity in patients surviving neonatal repair of esophageal atresia.

Esophageal atresia with or without tracheoesophageal fistula (EA ± TEF) occurs in 1 out of every 3000 births. Current survival approaches 95%, and research is therefore focused on morbidity and health-related quality of life issues. Up to 50% of neonates with EA ± TEF have one or more additional malformations including those of the respiratory tract that occur in a relatively high proportion of them and particularly of those with vertebral, anal, cardiac, tracheoesophageal, renal, and limb association. Additionally, a significant proportion of survivors suffer abnormal pulmonary function and chronic respiratory tract disease. The present review summarizes the current knowledge about the nature of these symptoms in patients treated for EA ± TEF, and explores the hypothesis that disturbed development and maturation of the respiratory tract could contribute to their pathogenesis.

Ganglioneuroma: to operate or not to operate.

INTRODUCTION: Ganglioneuroma (GN) is a benign, differentiated variety of neurogenic tumor. It is often asymptomatic and may be diagnosed by serendipity. Surgical removal is the treatment of choice. However, it has been suggested that postoperative complications and sequelae might outweigh the benefits of this approach. The purpose of the present study was to examine these issues in a large experience of neural tumors. METHODS: Patients treated between 1992 and 2012 were retrospectively reviewed. Modern imaging, measurement of catecholamine metabolite excretion and metaiodobenzylguanidine were used for workup. Surgical treatment aimed at complete resection. Complications and sequelae were recorded. Literature was searched for regrowth or malignant transformation of GN. RESULTS: Of 227 patients with neural tumors, 24 were GN patients (12 abdominal, 11 thoracic and 1 cervical with 8 dumbbell extensions). Six children were symptomatic (three with abdominal pain and mass, one with stridor or dysphonia, and one each with anisocoria and opsomyoclonus). However, 18 (75%) were asymptomatic and the diagnosis was incidental. Several tumors were large and involved more than one body space. There were no neurologic symptoms in eight cases with dumbbell extension. Complete resection was achieved in 20 children (83%) whereas gross residual was left in four. Postoperative complications were: Horner syndrome (3 patients), mild scoliosis (1 patient), adhesive bowel obstruction (1 patient) and acute urinary retention (1 patient). There was no evidence of either regrowth or malignant behavior in residual masses left in place after follow-up of 84 (1-194) months. CONCLUSIONS: There were a limited number of general minor complications in this series that did not include cases of regrowth or malignant transformation. However, these unfavorable events were occasionally reported in the literature. Since diagnosis of GN cannot be ascertained before removal of the mass, this should remain the aim of the treatment, although limiting the chances of complications to a minimum even if incomplete resection is the price to pay. Nonoperative attitudes should not be recommended in all cases, but they are certainly justified in some.

Maternal hyperthyroidism increases the prevalence of foregut atresias in fetal rats exposed to adriamycin.

PURPOSE: Gastrointestinal malformations such as esophageal atresia with tracheoesophageal fistula (EA/TEF) and duodenal atresia (DA) have been reported in infants born to hyperthyroid mothers or with congenital hypothyroidism. The present study aimed to test whether maternal thyroid status during embryonic foregut division has any influence on the prevalence of EA/TEF and DA in an accepted rat model of these malformations. METHODS: Pregnant rats received either vehicle or 1.75 mg/kg i.p. adriamycin on gestational days 7, 8 and 9. Transient maternal hyper or hypothyroidism was induced by oral administration of levothyroxine (LT4, 50 µg/kg/day) or propylthiouracil (PTU, 2 mg/kg/day), respectively, on days 7 to 12 of gestation. Plasma cholesterol, total T3, free T4 and TSH were measured at gestational days 7, 12, and 21. At the end of gestation, the mothers were sacrificed and embryo-fetal mortality was recorded. Fetuses were dissected to determine the prevalence of esophageal and intestinal atresias. RESULTS: At gestational day 12, mothers treated with LT4 or PTU had hyper or hypothyroid status, respectively; plasma cholesterol levels were similar. In the adriamycin-exposed fetuses from hyperthyroid mothers, the embryonal resorption rate and the prevalence of both EA/TEF and DA were significantly higher than in the other groups; maternal hypothyroidism during the same period did not have significant effect on the prevalence of atresias. CONCLUSIONS: Maternal hyperthyroidism during the embryonic window corresponding to foregut cleavage increased the prevalence of both EA/TEF and duodenal atresia in fetal rats exposed to adriamycin. This suggests that maternal thyroid hormone status might be involved in the pathogenesis of foregut atresias and invites further research on this likely clinically relevant issue in humans.

Management of chest trauma in children.

Chest trauma in children is caused by high-energy blows, due in general to traffic accidents, that involve several other body regions. They occur mainly in the first decade of life and can be penetrating but are more often non-penetrating. Rib fractures and lung contusions, sometimes associated with pneumothorax or haemothorax, are the more usual injuries, but tracheobronchial rupture, cardiac, oesophageal or diaphragmatic injuries may also occur. These injuries are treated with supportive respiratory and haemodynamic measures, drainage of air or blood from the pleural space and, at times, surgical repair of the injured organ(s). Ruptures of the airway may be difficult to treat and occasionally require suture, anastomosis or resection. Oesophageal injuries can be treated conservatively with antibiotics, drainage and parenteral nutrition. Diaphragmatic tears should be repaired operatively. Overall mortality ranges from 6 to 20%. Mortality is high but this is mainly due to the associated presence of extra-thoracic trauma, and particularly to head injuries.

Abnormal control of lung branching in experimental esophageal atresia.

PURPOSE: Esophageal atresia and tracheo-esophageal fistula (EA-TEF) result from abnormal division of the foregut into esophagus and trachea thus, it may influence airway branching and lung development. The present study examined lung morphogenesis in fetuses with EA-TEF focusing in the expression of FGF10 and its receptor FGFR2 IIIb. METHODS: Pregnant rats received either 1.75 mg/kg i.p. adriamycin or vehicle on E7, E8 and E9. Embryos were recovered at E15, E18 and E21 and lungs processed for immunohistochemistry and RT-PCR. Three groups were studied: control, adriamycin-exposed with EA-TEF, and adriamycin-exposed without EA-TEF. Comparisons were performed with Mann-Whitney or t tests (significance level, 5 %). RESULTS: Lung weight at E15 and E18 were significantly lower in adriaEA fetuses in which the relative mRNA levels of FGF10 were significantly higher. These differences disappeared near term. The receptor FGFR2 IIIb messenger was only significantly increased in adria noEA fetuses at E15. Immunohistochemical study was consistent with these findings. CONCLUSIONS: Abnormal expression of FGF10 during earlier stages of development, when the lungs are smaller than controls, suggests a compensatory response aimed at "catching up" delayed tracheobronchial branching. Whether similar changes take place in the human condition and influence respiratory physiology remain to be determined.

Osteolysis and lymphatic anomalies: a review of 54 consecutive cases.

BACKGROUND: Progressive osteolysis caused by lympathic malformations is a rare condition that should be known by specialists involved in the study of lymphatic disorders because they are necessarily involved in the treatment. The purpose of the present study is to report on a large series of patients to illustrate the multiple clinical pictures and the wide range of therapeutic measures necessary for arresting bone destruction and lymphatic leak. METHODS AND RESULTS: Inclusion criteria were osteolysis associated with lymphatic malformation that required treatment. Diagnosis was based on history, plain X-rays, MRI, and demonstration of the lymphatic nature of the lesions with D2-40 immunohistochemistry. Treatment was based on resection of the bone lytic lesion or soft tissue lymphatic masses, control of chylothorax or chyloperitoneum, interferon, zoledronic acid, and radiotherapy. The study included 54 patients (25 females and 29 males) with a median age of 9 years (range 2 to 65). Eight patients had focal osteolysis without soft tissue lymphatic anomaly, 15 multifocal osteolysis without soft tissue lymphatic anomaly, 7 focal osteolysis associated with soft tissue lymphatic anomaly, and 24 multifocal osteolysis with soft tissue lymphatic anomaly. Among the wide variety of pharmacological therapies provided, only one protocol showed a consistent positive effect (end of ostelytic progression) in 17 patients who received a course of 6 to 15 months of interferon alpha-2B at 1.5 million units/m(2) body surface area/day in association with zoledronic acid at 0.05 mg/kg/month. Thirty-two patients underwent multiple surgical procedures in order to remove the soft tissue involved, correct orthopedic problems, or improve chylothorax, and three were treated with radiotherapy which was successful in one case. CONCLUSIONS: Osteolysis from lymphatic origin is a devastating surgical condition. Therapeutic options have to be considered separately if the disease is active or inactive and according to the targeted organ (skin, bone, or viscera). Total removal of the lymphatic anomaly is rarely possible, but its subtotal excision together with pharmacological antiangiogenic therapy in selected patients under surveillance of a multidisciplinary group familiarized with the disease, minimize the progression of both, lymphatic invasion, osteolysis, and their serious complications.

Vaginal agenesis or distal vaginal atresia associated with anorectal malformations.

BACKGROUND: Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is defined as Müllerian aplasia with vaginal agenesis and uterine remnants. It is commonly associated with renal and sometimes vertebral anomalies. The MRKH syndrome or distal vaginal atresia is sometimes associated with anorectal malformations. The purpose of this study was to describe 7 girls with vaginal agenesis or distal vaginal atresia and an anorectal malformation and review the literature. METHODS: Seven patients with vaginal agenesis or distal vaginal atresia and anorectal malformation were operated on at 3 pediatric surgical centers in Madrid, Helsinki, and Stockholm. Case records were reviewed, and the previous literature was searched. RESULTS: Six patients had a reconstruction of the anorectum and vagina during the first year of life. In one case, the vagina was replaced at the time of a redo posterior sagittal anorectoplasty at the age of 11 years. The 4 patients with vaginal agenesis had a sigmoid colovaginoplasty. The 3 patients with a distal vaginal atresia had a vaginal pull-through. Four of the patients needed laxatives or enemas for mild constipation at last follow-up. Short-term gynecologic problems were minor in all patients. CONCLUSION: Vaginal reconstruction at the time of anorectoplasty results in good short-term outcome. For vaginal agenesis, a primary colovaginoplasty is suggested to be the preferred technique to replace the vagina.

Lung hypoplasia in rats with esophageal atresia and tracheo-esophageal fistula.

INTRODUCTION: Survivors of esophageal atresia and tracheo-esophageal fistula (EA-TEF) often suffer chronic respiratory tract disease. EA-TEF results from abnormal emergence of the trachea from the foregut. This study in a rat model tests the hypothesis that primary lung maldevelopment might be a downstream consequence of this defect. RESULTS: The lung was hypoplastic in rats with EA-TEF although the histological pattern was normal. Maturation and arteriolar wall thickness were unchanged, but mesenchymal control of airway branching was weakened. This branching was deficient from embryonal day (E13) on in adriamycin-treated explants. DISCUSSION: In conclusion, the lungs were hypoplastic in rats with experimental EA-TEF due to defective embryonal airway branching. However, arteriolar wall and respiratory epithelial patterns remained normal. These findings suggest that similarly defective lung development might contribute to chronic respiratory disease in EA-TEF patients. METHODS: Pregnant rats received either 1.75 mg/kg i.p. adriamycin or vehicle on E7, E8, and E9. Lungs were recovered at E15, E18, and E2. Lung weight/body weight ratio, total DNA and protein, radial alveolar count, arteriolar wall thickness, lung maturity, and mesenchymal control of airway branching were assessed. E13 lungs were cultured for 72 h and explant airway branching was measured daily. For comparisons, nonparametric tests (*P < 0.05) were used.

Congenital diaphragmatic hernia.

Congenital Diaphragmatic Hernia (CDH) is defined by the presence of an orifice in the diaphragm, more often left and posterolateral that permits the herniation of abdominal contents into the thorax. The lungs are hypoplastic and have abnormal vessels that cause respiratory insufficiency and persistent pulmonary hypertension with high mortality. About one third of cases have cardiovascular malformations and lesser proportions have skeletal, neural, genitourinary, gastrointestinal or other defects. CDH can be a component of Pallister-Killian, Fryns, Ghersoni-Baruch, WAGR, Denys-Drash, Brachman-De Lange, Donnai-Barrow or Wolf-Hirschhorn syndromes. Some chromosomal anomalies involve CDH as well. The incidence is < 5 in 10,000 live-births. The etiology is unknown although clinical, genetic and experimental evidence points to disturbances in the retinoid-signaling pathway during organogenesis. Antenatal diagnosis is often made and this allows prenatal management (open correction of the hernia in the past and reversible fetoscopic tracheal obstruction nowadays) that may be indicated in cases with severe lung hypoplasia and grim prognosis. Treatment after birth requires all the refinements of critical care including extracorporeal membrane oxygenation prior to surgical correction. The best hospital series report 80% survival but it remains around 50% in population-based studies. Chronic respiratory tract disease, neurodevelopmental problems, neurosensorial hearing loss and gastroesophageal reflux are common problems in survivors. Much more research on several aspects of this severe condition is warranted.

Retinoic acid rescues deficient airway innervation and peristalsis of hypoplastic rat lung explants.

BACKGROUND: Bronchial peristalsis modulates lung growth and is deficient in hypoplastic nitrofen-exposed rat lung explants. Retinoic acid (RA) rescues lung hypoplasia. This study examines whether decreased bronchial innervation contributes to this developmental deficiency and if RA is able to recover bronchial innervation and motility. MATERIAL AND METHODS: After IRB approval, pregnant rats received either 100 mg nitrofen or vehicle on gestational day 9.5 (E9.5). Embryonic lung primordia harvested on E13 were cultured for 72 h and RA was added daily to the medium when appropriate. Lung growth was assessed by counting the number of terminal buds and measuring explant surface, total DNA and protein in control, control + RA, nitrofen and nitrofen + RA groups. Peristaltic contractions were recorded for 10 min under an inverted microscope. Lung explants stained for anti-protein gene product 9.5 (PGP 9.5) and smooth muscle α-actin were examined under a confocal microscope for depicting the specific relationship between neural and smooth muscle cells. PGP 9.5 and smooth muscle α-actin levels were quantified by Western blot analysis for assessing the neural and muscle cell expressions. Comparisons between groups were made with non-parametric tests. RESULTS: The number of terminal buds, the explants' surface and the DNA and protein contents were significantly decreased in nitrofen-exposed lungs in comparison with controls. In contrast, these measurements were normal in explants exposed to both nitrofen and RA. Bronchial peristalsis (contractions/min) was significantly decreased in nitrofen-exposed lungs in comparison with controls; in contrast, in nitrofen + RA lungs it was similar to controls. In all study groups, the airways were surrounded by smooth muscle and ensheathed in a plexus of nerve fibers containing ganglia. PGP 9.5 protein levels were decreased in nitrofen-exposed lungs, but they normalized when RA was added. No differences were found in α-actin protein levels. Explants exposed only to RA were similar to control. CONCLUSIONS: Lung growth, bronchial innervation and peristalsis are decreased in nitrofen-exposed lung explants and are rescued by RA. If deficient airway innervation contributing to dysmotility and pulmonary hypoplasia can be pharmacologically rescued, new relatively simple prenatal interventions could be envisioned.

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.