Novel multidisciplinary approach to monitor and treat fetuses with gastroschisis using the Svetliza Reducibility Index and the EXIT-like procedure / Nova abordagem multidisciplinar para monitorizar e tratar fetos com gastrosquise utilizando o Svetliza Reducibility Index e o procedimento EXIT-like

ABSTRACT Objective: To describe our initial experience with a novel approach to follow-up and treat gastroschisis in "zero minute" using the EXITlike procedure. Methods: Eleven fetuses with prenatal diagnosis of gastroschisis were evaluated. The Svetliza Reductibility Index was used to prospectively evaluate five cases, and six cases were used as historical controls. The Svetliza Reductibility Index consisted in dividing the real abdominal wall defect diameter by the larger intestinal loop to be fitted in such space. The EXIT-like procedure consists in planned cesarean section, fetal analgesia and return of the herniated viscera to the abdominal cavity before the baby can fill the intestines with air. No general anesthesia or uterine relaxation is needed. Exteriorized viscera reduction is performed while umbilical cord circulation is maintained. Results: Four of the five cases were performed with the EXIT-like procedure. Successful complete closure was achieved in three infants. The other cases were planned deliveries at term and treated by construction of a Silo. The average time to return the viscera in EXIT-like Group was 5.0 minutes, and, in all cases, oximetry was maintained within normal ranges. In the perinatal period, there were significant statistical differences in ventilation days required (p = 0.0169), duration of parenteral nutrition (p=0.0104) and duration of enteral feed (p=0.0294). Conclusion: The Svetliza Reductibility Index and EXIT-like procedure could be new options to follow and treat gastroschisis, with significantly improved neonatal outcome in our unit. Further randomized studies are needed to evaluate this novel approach.

RESUMO Objetivo: Descrever a experiência inicial com a nova técnica cirúrgica EXIT-like para acompanhamento e correção de gastrosquise no "minuto zero". Métodos: Foram avaliados onze fetos com diagnóstico pré-natal de gastrosquise. O Svetliza Reducibility Index foi usado prospectivamente para avaliar cinco casos, e seis foram utilizados como controles. O índice foi calculado dividindo-se o diâmetro do defeito da parede abdominal pela maior alça intestinal que coubesse neste espaço. O procedimento EXIT-like compreendeu cesárea programada, analgesia fetal e redução da víscera herniada para a cavidade abdominal, antes da deglutição de ar pelo recém- nascido. Não são necessários anestesia geral e nem relaxamento uterino. A redução da víscera exteriorizada é realizada enquanto se mantém a circulação do cordão umbilical. Resultados: Quatro casos, dos cinco, foram submetidos ao EXIT-like. A correção foi completa em três casos. Os demais casos foram partos a termo planejados, e a correção do defeito foi feita com Silo. O tempo médio de redução da víscera foi de 5,0 minutos no grupo submetido ao procedimento EXITlike, e a oximetria foi mantida dentro dos valores de variação normal em todos os casos. No período perinatal, foram observadas diferenças estatisticamente significativas no tempo de ventilação mecânica (p=0,0169), duração da nutrição parenteral (p = 0,0104) e da nutrição enteral (p=0,0294). Conclusão: O Svetliza Reducibility Index e o procedimento EXIT-like podem ser novas opções para acompanhar e tratar gastroquise, com desfecho neonatal significativamente melhor em nossa unidade. Novos estudos randomizados são necessários para avaliar esta nova abordagem.

Novel multidisciplinary approach to monitor and treat fetuses with gastroschisis using the Svetliza Reducibility Index and the EXIT-like procedure.

OBJECTIVE: To describe our initial experience with a novel approach to follow-up and treat gastroschisis in "zero minute" using the EXITlike procedure. METHODS: Eleven fetuses with prenatal diagnosis of gastroschisis were evaluated. The Svetliza Reductibility Index was used to prospectively evaluate five cases, and six cases were used as historical controls. The Svetliza Reductibility Index consisted in dividing the real abdominal wall defect diameter by the larger intestinal loop to be fitted in such space. The EXIT-like procedure consists in planned cesarean section, fetal analgesia and return of the herniated viscera to the abdominal cavity before the baby can fill the intestines with air. No general anesthesia or uterine relaxation is needed. Exteriorized viscera reduction is performed while umbilical cord circulation is maintained. RESULTS: Four of the five cases were performed with the EXIT-like procedure. Successful complete closure was achieved in three infants. The other cases were planned deliveries at term and treated by construction of a Silo. The average time to return the viscera in EXIT-like Group was 5.0 minutes, and, in all cases, oximetry was maintained within normal ranges. In the perinatal period, there were significant statistical differences in ventilation days required (p = 0.0169), duration of parenteral nutrition (p=0.0104) and duration of enteral feed (p=0.0294). CONCLUSION: The Svetliza Reductibility Index and EXIT-like procedure could be new options to follow and treat gastroschisis, with significantly improved neonatal outcome in our unit. Further randomized studies are needed to evaluate this novel approach.

Advances in fetal surgery.

This paper discusses the main advances in fetal surgical therapy aiming to inform health care professionals about the state-of-the-art techniques and future challenges in this field. We discuss the necessary steps of technical evolution from the initial open fetal surgery approach until the development of minimally invasive techniques of fetal endoscopic surgery (fetoscopy).

Advances in fetal surgery / Avanços em cirurgia fetal

ABSTRACT This paper discusses the main advances in fetal surgical therapy aiming to inform health care professionals about the state-of-the-art techniques and future challenges in this field. We discuss the necessary steps of technical evolution from the initial open fetal surgery approach until the development of minimally invasive techniques of fetal endoscopic surgery (fetoscopy).

RESUMO São discutidos os principais avanços na terapia cirúrgica do feto, tendo como objetivo informar profissionais da área da saúde sobre qual o estado atual da arte e quais seus desafios futuros. São debatidos os passos que foram necessários para a evolução da técnica inicial, quando a cirurgia fetal era realizada a céu aberto, até o desenvolvimento de técnicas minimamente invasivas, de cirurgia endoscópica fetal (fetoscopia).

Fetoscopy for meningomyelocele repair: past, present and future.

Meningomyelocele is a malformation with high prevalence, and one of its main comorbidities is Arnold-Chiari malformation type II. The intrauterine repair of this defect has been studied to reduce the progressive spinal cord damage during gestation. The purpose of the present review was to describe the evolution of fetal surgery for meningomyelocele repair. Searches on PubMed database were conducted including articles published in the last 10 years. Twenty-seven articles were selected, 16 experimental studies and 11 studies in humans. A recent study demonstrated that the fetal correction results in better prognosis of neurological and psychomotor development, but open surgery, which has being used widely, has considerable maternal risks. Studies in animal and human models show that the endoscopic approach is feasible and leads to lower maternal morbidity rates. Two endoscopic techniques are currently under assessment - one in Germany and another in Brazil, and we believe that the endoscopic approach will be the future technique for prenatal repair of this defect.

Fetoscopy for meningomyelocele repair: past, present and future / Cirurgia fetal endoscópica para correção de mielomeningocele: passado, presente e futuro

ABSTRACT Meningomyelocele is a malformation with high prevalence, and one of its main comorbidities is Arnold-Chiari malformation type II. The intrauterine repair of this defect has been studied to reduce the progressive spinal cord damage during gestation. The purpose of the present review was to describe the evolution of fetal surgery for meningomyelocele repair. Searches on PubMed database were conducted including articles published in the last 10 years. Twenty-seven articles were selected, 16 experimental studies and 11 studies in humans. A recent study demonstrated that the fetal correction results in better prognosis of neurological and psychomotor development, but open surgery, which has being used widely, has considerable maternal risks. Studies in animal and human models show that the endoscopic approach is feasible and leads to lower maternal morbidity rates. Two endoscopic techniques are currently under assessment - one in Germany and another in Brazil, and we believe that the endoscopic approach will be the future technique for prenatal repair of this defect.

RESUMO A meningomielocele é uma malformação de alta incidência e, dentre suas principais comorbidades, está a malformação de Arnold-Chiari tipo II. A fim de reduzir os danos progressivos durante a gestação, tanto a nível medular, quanto sobre a fossa posterior, a correção intrauterina desse defeito vem sendo estudada. A presente revisão teve por objetivo descrever a evolução da cirurgia fetal para a correção da meningomielocele. Foi realizada uma pesquisa na base de dados PubMed, incluindo artigos publicados nos últimos 10 anos. Foram selecionados 27 artigos, sendo 16 de estudos experimentais e 11 sobre pesquisa em humanos. Um estudo recente demonstrou que a correção pré-natal resulta em melhor prognóstico neuropsicomotor, porém a abordagem a céu aberto, que vem sendo amplamente utilizada, possui um risco materno considerável. Estudos, tanto em modelo animal, quanto em humanos, mostram que a abordagem endoscópica é factível e apresenta menor morbidade materna. No momento, duas técnicas de abordagem endoscópica estão sendo estudadas, uma na Alemanha, e outra no Brasil, e acreditamos que a via endoscópica será o futuro da correção pré-natal desse defeito.

Prenatal diagnosis of congenital rubella infection in São Paulo / Diagnóstico pré-natal de infecção congênita por rubéola, em São Paulo, Brasil

Objective: rubella during the early stages of pregnancy can lead to severe birth defects known as congenital rubella syndrome (CRS). Samples collected from pregnant women with symptoms and suspected of congenital rubella infection between 1996 and 2008 were analyzed. Methods: a total of 23 amniotic fluid samples, 16 fetal blood samples, 1 product of conception and 1 placenta were analyzed by serology and RT-PCR. Results: all patients presented positive serology for IgG / IgM antibodies to rubella virus. Among neonates, 16 were IgG-positive, 9 were IgM-positive and 4 were negative for both antibodies. Of the 25 samples analyzed in this study, 24 were positive by RT-PCR. Changes in ultrasound were found in 15 (60%) of 25 fetuses infected with rubella virus. Fetal death and miscarriage were reported in 10 (40%) of the 25 cases analyzed. The rubella virus was amplified by PCR in all fetuses with abnormal ultrasound compatible with rubella. Fetal death and abortion were reported in 10 of 25 cases analyzed. Conclusion: this study, based on primary maternal rubella infection definitely confirms the good sensitivity and specificity of RT-PCR using amniotic fluid and ultrasound. The results showed that molecular assays are important tools in the early diagnosis of rubella and congenital rubella syndrome. .

Objetivo: a rubéola, durante os primeiros estágios da gravidez, pode levar a graves defeitos congênitos, conhecidos como síndrome da rubéola congênita (SRC). Amostras de gestantes com sintomas e suspeitas da rubéola congênita foram coletadas entre 1996 e 2008. Métodos: um total de 23 amostras de fluido amniótico, 16 amostras de sangue fetal, um produto da concepção e uma placenta foram analisados por sorologia e PCR. Resultados: todas as gestantes apresentaram sorologia positiva para IgG/IgM para o vírus da rubéola. Entre os recém-nascidos, 14 apresentaram anticorpos IgG positivos e 11 foram os anticorpos IgM positivos. Das 25 amostras analisadas neste estudo, 24 eram positivas por RT-PCR. Alterações na ultrassonografia foram encontradas em 15 (60%) dos 25 fetos infectados com o vírus da rubéola. Morte fetal e aborto espontâneo foram reportados em 10 (40%) dos 25 casos analisados. O vírus da rubéola foi amplificado por PCR em todos os fetos que apresentaram alterações na ultrassonografia, compatíveis com a rubéola. Morte fetal e aborto foram relatados em 10 dos 25 casos analisados. Conclusão: os resultados mostraram que os ensaios moleculares são ferramentas importantes para o diagnóstico precoce da rubéola e da síndrome da rubéola congênita. .

Comparison between two surgical techniques for prenatal correction of meningomyelocele in sheep / Comparação entre duas técnicas cirúrgicas de correção intrauterina da mielomeningocele em fetos de ovelha

OBJECTIVE: To compare the classical neurosurgical technique with a new simplified technique for prenatal repair of a myelomeningocelelike defect in sheep. METHODS: A myelomeningocele-like defect (laminectomy and dural excision) was created in the lumbar region on day 90 of gestation in 9 pregnant sheep. Correction technique was randomized. In Group 1 the defect was corrected using the classic neurosurgical technique of three-layer suture (dura mater, muscle and skin closure) performed by a neurosurgeon. In Group 2, a fetal medicine specialist used a biosynthetic cellulose patch to protect the spinal cord and only the skin was sutured above it. Near term (day 132 of gestation) fetuses were sacrificed for pathological analysis. RESULTS: There were two miscarriages and one maternal death. In total, six cases were available for pathological analysis, three in each group. In Group 1, there were adherence of the spinal cord to the scar (meningo-neural adhesion) and spinal cord architecture loss with posterior funiculus destruction and no visualization of grey matter. In Group 2, we observed in all cases formation of a neo-dura mater, separating the nervous tissue from adjacent muscles, and preserving the posterior funiculus and grey matter. CONCLUSION: The new simplified technique was better than the classic neurosurgical technique. It preserved the nervous tissue and prevented the adherence of the spinal cord to the scar. This suggests the current technique used for the correction of spina bifida in humans may need to be reassessed.

OBJETIVO: Comparar a técnica neurocirúrgica clássica a uma nova técnica simplificada, para correção de mielomeningocele, em fetos de ovelhas. MÉTODOS: Em 9 fetos, foi criado um defeito semelhante à mielomeningocele (laminectomia e excisão de dura-máter) no 90º dia de gestação. O tipo de correção foi randomizado. No Grupo 1, o defeito foi corrigido usando a técnica neurocirúrgica clássica, com a sutura de três camadas (dura-máter, músculo e pele), realizada por um neurocirurgião. No Grupo 2, um especialista em Medicina Fetal utilizou a técnica simplificada, colocando um fragmento de celulose biossintética sobre a medula e suturando apenas da pele sobre a celulose. Próximo ao termo da gestação (132 dias), os fetos foram sacrificados para análise anatomopatológica. RESULTADOS: Ocorreram dois casos de aborto e uma morte materna, restando seis casos para avaliação - três em cada grupo. No Grupo 1, todos os casos mostraram aderência da medula à cicatriz (meningoadesão) e perda da arquitetura medular, com destruição do funículo posterior e perda da visualização da substância cinzenta. No Grupo 2, observou-se, em todos os casos, a formação de uma neodura-máter, separando o tecido nervoso do músculo adjacente, sendo que o funículo posterior e a substância cinzenta estavam preservados. CONCLUSÃO: A técnica simplificada foi superior à neurocirúrgica, com maior preservação da medula e evitando as aderências do tecido nervoso. Os presentes achados sugerem que a técnica utilizada atualmente na correção de mielomeningocele em fetos humanos deva ser reavaliada.

Comparison between two surgical techniques for prenatal correction of meningomyelocele in sheep.

OBJECTIVE: To compare the classical neurosurgical technique with a new simplified technique for prenatal repair of a myelomeningocele-like defect in sheep. METHODS: A myelomeningocele-like defect (laminectomy and dural excision) was created in the lumbar region on day 90 of gestation in 9 pregnant sheep. Correction technique was randomized. In Group 1 the defect was corrected using the classic neurosurgical technique of three-layer suture (dura mater, muscle and skin closure) performed by a neurosurgeon. In Group 2, a fetal medicine specialist used a biosynthetic cellulose patch to protect the spinal cord and only the skin was sutured above it. Near term (day 132 of gestation) fetuses were sacrificed for pathological analysis. RESULTS: There were two miscarriages and one maternal death. In total, six cases were available for pathological analysis, three in each group. In Group 1, there were adherence of the spinal cord to the scar (meningo-neural adhesion) and spinal cord architecture loss with posterior funiculus destruction and no visualization of grey matter. In Group 2, we observed in all cases formation of a neo-dura mater, separating the nervous tissue from adjacent muscles, and preserving the posterior funiculus and grey matter. CONCLUSION: The new simplified technique was better than the classic neurosurgical technique. It preserved the nervous tissue and prevented the adherence of the spinal cord to the scar. This suggests the current technique used for the correction of spina bifida in humans may need to be reassessed.

Neoskin development in the fetus with the use of a three-layer graft: an animal model for in utero closure of large skin defects.

OBJECTIVE: To assess the ability of a three-layer graft in the closuse of large fetal skin defects. METHODS: Ovine fetuses underwent a large (4 × 3 cm) full-thickness skin defect over the lumbar region at 105 days' gestation (term = 140 days). A bilaminar artificial skin was placed over a cellulose interface to cover the defect (3-layer graft). The skin was partially reapproximated with a continuous nylon suture. Pregnancy was allowed to continue and the surgical site was submitted to histopathological analysis at different post-operative intervals. RESULTS: Seven fetuses underwent surgery. One maternal/fetal death occurred, and the remaining 6 fetuses were analyzed. Artificial skin adherence to the wound edges was observed in cases that remained in utero for at least 15 days. Neoskin was present beneath the silicone layer of the bilaminar artificial skin. CONCLUSIONS: Our study shows that neoskin can develop in the fetus using a 3-layer graft, including epidermal growth beneath the silicone layer of the bilaminar skin graft. These findings suggest that the fetus is able to reepithelialise even large skin defects. Further experience is necessary to assess the quality of this repair.

Modification of the gasless fetoscopy technique for the treatment of large myelomeningocele: a study in sheep / Modificação da técnica de fetoscopia de suspensão para tratamento fetal de grandes meningomieloceles: estudo em ovelhas

Objective: To change the gasless fetoscopy technique in order to reduce the diameter of entry orifices in the myometrium. Methods: Seven pregnant ewes were submitted to fetoscopy for repairing a large skin defect measuring 4.0 x 3.0 cm, created in the fetal lumbar region at the gestational age of 100 days. The defect was repaired through continuous suture of the skin with approximation of borders. Gasless fetoscopy was used for performing the suture with three orifices to allow entry of the trocar into the myometrium. A 5.0-mm optical trocar, and 3.5-mm grasping, dissecting and suturing forceps were used. After surgery, pregnancy was maintained until the animals were euthanized on the 133rd day of gestation, and the fetuses were evaluated. Results: Seven pregnant ewes underwent surgery; the first two cases were characterized as the Pilot Group, in which the endoscopic technique was modified and caliber reduction was possible in two out of three entry orifices in the myometrium. In the five remaining cases (Study Group), the repair was successfully carried out in all the fetuses, and the mean duration of fetoscopy was 98 minutes. There was a case of maternal death attributed to intrauterine infection. Mean intrauterine permanence after surgery was 12 days. Conclusions: The technique was successfully modified, allowing reduction of the uterine orifices necessary to perform the repair of a skin defect in the fetal lumbar region through a new fetoscopy technique. The impact of this modification in repair of myelomeningocele in human fetuses should be studied.

Objetivo: Modificar a técnica de fetoscopia de suspensão para redução do calibre dos orifícios de entrada no miométrio. Métodos: Sete ovelhas grávidas foram submetidas à fetoscopia para correção de um grande defeito de pele medindo 4,0 x 3,0 cm, criado na região lombar fetal com 100 dias de gestação. O defeito era corrigido através de sutura contínua da pele, aproximando-se as suas bordas. Para realizar a sutura, foi realizada a fetoscopia de suspensão, utilizando-se três orifícios para entrada de trocarte no miométrio. O trocarte da ótica era de 5,0 mm e das pinças de apreensão, dissecção e sutura eram de 3,5 mm. Após a cirurgia, a gestação era mantida até o sacrifício, realizado no 133º dia de gestação, quando os fetos eram avaliados. Resultados: Sete ovelhas prenhes foram operadas. Os dois primeiros casos constituíram o Grupo Piloto, no qual a técnica endoscópica foi modificada e a redução do calibre foi possível em dois dos três orifícios de entrada no miométrio. Nos cinco demais casos (Grupo de Estudo) a correção foi realizada com sucesso em todos os fetos e o tempo médio de duração da fetoscopia foi de 98 minutos. Houve um caso de morte materna atribuído à infecção intrauterina. A média de permanência intraútero após a cirurgia foi de 12 dias. Conclusões: A técnica foi modificada com sucesso, permitindo a redução do calibre dos orifícios uterinos necessários para realizar a correção de um defeito de pele na região lombar do feto através de uma nova técnica de fetoscopia. O impacto desta modificação na correção da meningomielocele em fetos humanos deve ser estudado.

Modification of the gasless fetoscopy technique for the treatment of large myelomeningocele: a study in sheep.

OBJECTIVE: To change the gasless fetoscopy technique in order to reduce the diameter of entry orifices in the myometrium. METHODS: Seven pregnant ewes were submitted to fetoscopy for repairing a large skin defect measuring 4.0 × 3.0 cm, created in the fetal lumbar region at the gestational age of 100 days. The defect was repaired through continuous suture of the skin with approximation of borders. Gasless fetoscopy was used for performing the suture with three orifices to allow entry of the trocar into the myometrium. A 5.0-mm optical trocar, and 3.5-mm grasping, dissecting and suturing forceps were used. After surgery, pregnancy was maintained until the animals were euthanized on the 133rd day of gestation, and the fetuses were evaluated. RESULTS: Seven pregnant ewes underwent surgery; the first two cases were characterized as the Pilot Group, in which the endoscopic technique was modified and caliber reduction was possible in two out of three entry orifices in the myometrium. In the five remaining cases (Study Group), the repair was successfully carried out in all the fetuses, and the mean duration of fetoscopy was 98 minutes. There was a case of maternal death attributed to intrauterine infection. Mean intrauterine permanence after surgery was 12 days. CONCLUSIONS: The technique was successfully modified, allowing reduction of the uterine orifices necessary to perform the repair of a skin defect in the fetal lumbar region through a new fetoscopy technique. The impact of this modification in repair of myelomeningocele in human fetuses should be studied.

Simplified correction of a meningomyelocele-like defect in the ovine fetus.

PURPOSE: To develop a simplified technique for antenatal correction of a meningomyelocele -like defect in fetal sheep to allow direct skin closure. METHODS: A spinal defect was surgically created at 75 days of gestation in the fetuses of 36 pregnant sheep, 23 survived the surgery. At 102 days gestation, the defect was corrected in 14 cases (9 were left untreated). Skin surrounding the defect was dissected below the dermis to permit its edges to be approximated and sutured, without interposing any material to its edges. An interface material intended to protect the neural tissue from skin adhesion was used and the skin defect was completely closed over it. Pregnancy was allowed to continue up to 138 days gestation, the fetuses were submitted to macroscopic and microscopic analysis. RESULTS: The defect was successfully corrected in 90.9% in the experimental group, and spontaneous closure occurred in 22.3% in the control group (p < 0.05). The survival rate after the creation and correction of the defect was 63.4% and 78% respectively. CONCLUSION: This simplified technique was successful in the correction a meningomyelocele-like defect, in the fetal sheep.

Simplified correction of a meningomyelocele-like defect in the ovine fetus / Correção simplificada de um defeito semelhante à meningomielocele em fetos de ovelha

PURPOSE: To develop a simplified technique for antenatal correction of a meningomyelocele -like defect in fetal sheep to allow direct skin closure. METHODS: A spinal defect was surgically created at 75 days of gestation in the fetuses of 36 pregnant sheep, 23 survived the surgery. At 102 days gestation, the defect was corrected in 14 cases (9 were left untreated). Skin surrounding the defect was dissected below the dermis to permit its edges to be approximated and sutured, without interposing any material to its edges. An interface material intended to protect the neural tissue from skin adhesion was used and the skin defect was completely closed over it. Pregnancy was allowed to continue up to 138 days gestation, the fetuses were submitted to macroscopic and microscopic analysis. RESULTS: The defect was successfully corrected in 90.9 percent in the experimental group, and spontaneous closure occurred in 22.3 percent in the control group (p < 0.05). The survival rate after the creation and correction of the defect was 63.4 percent and 78 percent respectively. CONCLUSION: This simplified technique was successful in the correction a meningomyelocele-like defect, in the fetal sheep.

OBJETIVO: Desenvolver uma técnica simplificada de correção pré-natal de defeito semelhante à mielomeningocele em fetos de ovelha permitindo um fechamento direto da pele. MÉTODOS: Um defeito espinhal foi cirurgicamente criado com 75 dias de gestação, em 36 fetos de ovelha, 23 sobreviveram à cirurgia. Após 102 dias de gestação, o defeito foi corrigido em 14 casos (9 não foram tratados). A pele em volta do defeito foi dissecada abaixo da derme para permitir a aproximação direta das bordas através de sutura, sem a interposição de nenhum material entre a pele. Um material de interface foi colocado entre o tecido neural exposto e a pele, com o objetivo de evitar a adesão da medula à pele, que foi completamente fechada sobre o defeito. A gravidez foi mantida até 138 dias, os fetos foram submetidos a análises macroscópicas e microscópicas. RESULTADOS: O defeito foi corrigido em 90.9 por cento no grupo experimental, e o fechamento espontâneo ocorreu em 22.3 por cento no grupo controle (p < 0.05). A taxa de sobrevivência após a criação do defeito e posteriormente a sua correção foi de 63,4 por cento e 78 por cento, respectivamente. CONCLUSÃO: Esta técnica simplificada teve sucesso na correção do defeito semelhante à mielomeningocele em feto de ovelha.

Biosynthetic cellulose induces the formation of a neoduramater following pre-natal correction of meningomyelocele in fetal sheep.

PURPOSE: The aim of this study was to compare the effectiveness of two dura-mater substitutes, namely human acellular dermal matrix (HADM) and biosynthetic cellulose (BC), in repairing, in utero, surgically-induced meningomyelocele (MMC) in fetal sheep. METHODS: A neural tube defect was created at 74-77 days gestation in 36 fetal sheep. They were divided into 3 groups, the control group that did not receive pre-natal corrective surgery, and the other two groups that received corrective surgery using HADM (Group A) or BC (Group B). Both materials were used as a dura-mater substitutes between the neural tissue and the sutured skin. Correction was performed at gestation day 100 and the fetuses were maintained in utero until term. Sheep were sacrificed on gestation day 140. The fetal spine was submitted to macro and microscopic analysis. At microscopy, adherence of the material to the skin and neural tissue was analyzed. RESULTS: In the initial phase (pilot), experimentally-induced MMC was performed on 11 fetuses and 4 survived (37%). In the second phase (study), 25 fetuses received surgery and 17 survived (68%). In the study group, 6 fetuses did not undergo repair (control group), 11 cases were submitted to corrective surgery (experimental group) and one fetal loss occurred. Of the surviving cases in the experimental group, 4 constituted Group A and 6 in Group B. Macroscopically, skin and underlying tissues where easily displaced from the BC in all cases it was used; in contrast, HADM adhered to these tissues. To compare the adherence, 4 cases from Group A and 4 in Group B were studied. We observed adherence, host cell migration and vessel proliferation into the HADM all sections from Group A and this aspect was not present in any cases in Group B (p < 0.05). In Group B, we also observed that a new fibroblast layer formed around the BC thus protecting the medulla and constituting a "neoduramater". CONCLUSION: The use of BC seems to be more adequate as a dura-mater substitute to cover the damaged neural tissue than HADM. It seems promising for use in the in utero correction of MMC because to does not adhere to neural tissue of superficial and deep layers ("tethered spinal cord"). Thus, BC minimizes the mechanical and chemical intrauterine damage to the spinal medulla.

Validation of the ovine fetus as an experimental model for the human myelomeningocele defect.

PURPOSE: To produce a myelomeningocele-like human defect in the ovine fetus and validate this experimental model in our population. METHODS: A prospective study on 12 pregnant sheep of a crossed Hampshire/Down breed where a spinal defect was surgically created between Day 75 and Day 77 after conception. The technique consisted of a hysterotomy with exposure of fetal hind limbs and tail up to the mid spine. Fetal skin, paravertebral muscles, and 4 posterior spinal arches were excised, exposing the spinal cord. Duramater was opened and the medulla was incised until the medullar canal. Animals were euthanized at 139 days of gestation for fetal evaluation. The central nervous system was submitted to post-mortem magnetic resonance imaging (MRI) and the spine was submitted to pathological examination. RESULTS: The defect was created in 13 fetuses and 5 survived. Mean gestational age at necropsy was 121.6 days (varying from 93 to 145 days). Macroscopically, the defect was present in 4 cases. Microscopy revealed a flattened medulla with disappearance of the medullar canal and disruption of normal medullar architecture with neuronal apoptosis and/or fusion of the piamater and duramater. The MRI showed herniation of the cerebellum into the cervical canal and syringomyelia. CONCLUSIONS: The surgically produced defect mimics the defect found in the human fetus, including the Arnold-Chiari malformation. Post-mortem MRI was used for the first time in our study and proved an excellent alternative for demonstrating the cerebellar herniation. We standardized the technique for creating the defect in our population.

Validation of the ovine fetus as an experimental model for the human myelomeningocele defect

PURPOSE: To produce a myelomeningocele-like human defect in the ovine fetus and validate this experimental model in our population. METHODS: A prospective study on 12 pregnant sheep of a crossed Hampshire/Down breed where a spinal defect was surgically created between Day 75 and Day 77 after conception. The technique consisted of a hysterotomy with exposure of fetal hind limbs and tail up to the mid spine. Fetal skin, paravertebral muscles, and 4 posterior spinal arches were excised, exposing the spinal cord. Duramater was opened and the medulla was incised until the medullar canal. Animals were euthanized at 139 days of gestation for fetal evaluation. The central nervous system was submitted to post-mortem magnetic resonance imaging (MRI) and the spine was submitted to pathological examination. RESULTS: The defect was created in 13 fetuses and 5 survived. Mean gestational age at necropsy was 121.6 days (varying from 93 to 145 days). Macroscopically, the defect was present in 4 cases. Microscopy revealed a flattened medulla with disappearance of the medullar canal and disruption of normal medullar architecture with neuronal apoptosis and/or fusion of the piamater and duramater. The MRI showed herniation of the cerebellum into the cervical canal and syringomyelia. CONCLUSIONS: The surgically produced defect mimics the defect found in the human fetus, including the Arnold-Chiari malformation. Post-mortem MRI was used for the first time in our study and proved an excellent alternative for demonstrating the cerebellar herniation. We standardized the technique for creating the defect in our population.

OBJETIVO: Produzir um defeito semelhante a meningomielocele humana em feto de ovinos, validando este modelo experimental, em nosso meio. MÉTODOS: Estudo prospectivo com 12 ovelhas de cruzamento das raças Hampshire e Down, onde um defeito na coluna foi criado cirurgicamente com 75 a 77 dias de gestação. A técnica consistiu em histerotomia com exposição das patas traseiras e cauda até a metade da coluna fetal. Foram retirados pele, musculatura paravertebral e 4 arcos vertebrais posteriores, expondo a medula. A dura foi aberta e uma incisão até o canal medular foi realizada. O sacrifício foi realizado com 139 dias de gestação para avaliação fetal. O sistema nervoso central foi submetido a ressonância magnética (REMA) post-mortem e a coluna foi submetida a exame anátomo-patológico. RESULTADOS: O defeito foi criado em 13 fetos e 5 sobreviveram. A idade gestacional média da necropsia foi de 121,6 dias (variando de 93 a 145 dias). Macroscopicamente o defeito estava presente em 4 casos. A microscopia revelou achatamento da medula, com desaparecimento do canal medular e desarranjo da citoarquitetura medular com apoptose neuronal e/ou fusão da pia e dura-máter. A REMA demonstrou herniação do cerebelo para o canal cervical e siringomelia. CONCLUSÕES: O defeito produzido foi muito semelhante à meningomielocele em fetos humanos, levando inclusive à mal-formação de Arnold-Chiari. A REMA post-mortem, utilizada de forma inédita neste estudo, demonstrou ser uma excelente alternativa para demonstrar a presença da herniação do cerebelo. A técnica para produzir o defeito foi padronizada em nosso meio.

Biosynthetic cellulose induces the formation of a neoduramater following pre-natal correction of meningomyelocele in fetal sheep

PURPOSE: The aim of this study was to compare the effectiveness of two dura-mater substitutes, namely human acellular dermal matrix (HADM) and biosynthetic cellulose (BC), in repairing, in utero, surgically-induced meningomyelocele (MMC) in fetal sheep. METHODS: A neural tube defect was created at 74-77 days gestation in 36 fetal sheep. They were divided into 3 groups, the control group that did not receive pre-natal corrective surgery, and the other two groups that received corrective surgery using HADM (Group A) or BC (Group B). Both materials were used as a dura-mater substitutes between the neural tissue and the sutured skin. Correction was performed at gestation day 100 and the fetuses were maintained in utero until term. Sheep were sacrificed on gestation day 140. The fetal spine was submitted to macro and microscopic analysis. At microscopy, adherence of the material to the skin and neural tissue was analyzed. RESULTS: In the initial phase (pilot), experimentally-induced MMC was performed on 11 fetuses and 4 survived (37 percent). In the second phase (study), 25 fetuses received surgery and 17 survived (68 percent). In the study group, 6 fetuses did not undergo repair (control group), 11 cases were submitted to corrective surgery (experimental group) and one fetal loss occurred. Of the surviving cases in the experimental group, 4 constituted Group A and 6 in Group B. Macroscopically, skin and underlying tissues where easily displaced from the BC in all cases it was used; in contrast, HADM adhered to these tissues. To compare the adherence, 4 cases from Group A and 4 in Group B were studied. We observed adherence, host cell migration and vessel proliferation into the HADM all sections from Group A and this aspect was not present in any cases in Group B (p < 0.05). In Group B, we also observed that a new fibroblast layer formed around the BC thus protecting the medulla and constituting a "neoduramater". CONCLUSION: The use of BC...

OBJETIVO: Estudar os efeitos do emprego de dois materiais consideravelmente diferentes quanto à origem e custo na correção intra-uterina da meningomielocele criada experimentalmente em feto de ovino. MÉTODOS: Em 36 fetos de ovinos foi criado um defeito aberto de tubo neural, com 75 de dias de gestação. Os casos foram divididos em três grupos: o controle onde o defeito não foi corrigido, grupo corrigido A onde o material utilizado para cobrir a medula exposta foi a matriz dérmica humana acelular (MDHA) e o grupo corrigido B onde o material foi a celulose biossintética (CB). Após a correção realizada com 100 dias, os fetos eram mantidos intra-útero até o termo da gestação. Os sacrifícios foram realizados com 140 dias e a coluna fetal era submetida à análise macro e microscópica onde foi observada a aderência dos materiais à pele, medula ou tecido nervoso remanescente. RESULTADOS: Na fase inicial (piloto), 11 fetos foram operados e 4 sobreviveram (37 por cento). Na segunda fase (estudo) 25 fetos foram operados e 17 sobreviveram (68 por cento). No grupo de estudo, 6 fetos não foram submetidos à correção (grupo controle), 11 casos foram corrigidos e ocorreu 1 perda fetal. Do total de 10 casos, 4 constituíram o grupo A e 6, o grupo B. A macroscopia observou-se deslizamento da pele e tecidos subjacentes sobre a CB em todos os casos onde ela foi empregada e isto não ocorreu em nenhum dos casos onde a MDHA foi utilizada. Para comparar a aderência, foram considerados 4 casos do grupo A e 4 do grupo B. A aderência, caracterizada pela migração de células do hospedeiro e proliferação de vasos para dentro da MDHA, foi observada em 100 por cento dos casos do grupo A e em nenhum caso no grupo B (p < 0,05). No grupo B observou-se formação de uma camada de fibroblastos ao redor do material, protegendo a medula, caracterizando a formação de uma "neoduramater". CONCLUSÃO: A utilização da película de celulose biossintética parece ser mais adequada como substituto...

Validação do feto ovino como modelo experimental para o defeitomeningomielocele humana: estudo piloto / Validation of the ovine fetus as an experimental model for the human myelomeningocele defect: a pilot study

O objetivo deste trabalho foi produzir um defeito semelhante meningomielocele humanaem feto de ovinos, validando este modelo experimental, em nosso meio. Estudo prospectivo com 12 ovelhas de cruzamento das raças Hampshire e Down, onde um defeito na coluna foi criado cirurgicamente com 75 a 77 dias de gestação. A técnica consistiu emhisterotomia com exposição das patas traseiras e cauda até a metadeda coluna fetal. Foram retirados pele, musculatura paravertebral e quatro arcos vertebrais posteriores, expondo a medula. A dura foi aberta e uma incisão até o canal medular foi realizada. O sacrifício foi realizado com 139 dias de gestação para avaliação fetal. O sistemanervoso central foi submetido a ressonância magnética post-morteme a coluna foi submetida a exame anatomopatológico. O defeito foi criado em 13 fetos e 5 sobreviveram. A idade gestacional média da necropsia foi de 121,6 dias (variando de 93 a 145 dias).Macroscopicamente, o defeito estava presente em quatro casos. A microscopia revelou achatamento da medula, com desaparecimentodo canal medular e desarranjo da citoarquitetura medular com apoptose neuronal e/ou fusão da pia e dura-máter. A ressonância magnética demonstrou herniação do cerebelo para o canal cervical e siringomelia. Conclusões: O defeito produzido foi muito semelhante à meningomielocele em fetos humanos, levando inclusive àmalformação de Arnold-Chiari. A ressonância magnética postmortem,utilizada de forma inédita neste estudo, demonstrou ser uma excelente alternativa para demonstrar a presença da herniação do cerebelo. A técnica para produzir o defeito foi padronizada em nosso meio.