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

Denise Araujo Lapa Pedreira,Silvia Rejane Fontoura Herrera,Paulo Hilário Nascimento Saldiva,Élia Garcia Caldini,Paulo Roberto Valente,Ricardo José De Almeida Leme

doi:10.1590/s1679-45082012000400011

Denise Araujo Lapa Pedreira, Silvia Rejane Fontoura Herrera + Show 4 more

Open Access

https://doi.org/10.1590/s1679-45082012000400011

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Abstract

To compare the classical neurosurgical technique with a new simplified technique for prenatal repair of a myelomeningocele-like defect in sheep. 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. 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. 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.

Highlights

INTRODUCTION456 Herrera SR, Leme RJ, Valente PR, Caldini EG, Saldiva PH, Pedreira DA and orthopedic abnormalities[1], as well as central nervous system changes resulting from type II Arnold Chiari malformation, which is present in more than 75% of the affected individuals[2]
Meningomyelocele is a defect of the primary neurulation, which results from failure of fusing the caudal neural tube[1]
Experimental studies suggest that the spinal cord is progressively damaged during intrauterine life due to the exposure of the normal nervous tissue to mechanic and chemical aggressions resulting from the lack of closure of posterior structures[5]

Summary

INTRODUCTION

456 Herrera SR, Leme RJ, Valente PR, Caldini EG, Saldiva PH, Pedreira DA and orthopedic abnormalities[1], as well as central nervous system changes resulting from type II Arnold Chiari malformation, which is present in more than 75% of the affected individuals[2]. Despite the neurological advantages, maternal and fetal complications were observed. The development of less invasive surgical techniques may significantly improve the antenatal treatment of the disease. Our group successfully developed a sonoendoscopic technique using gasless fetoscopy[7] for fetal treatment. In order to allow endoscopic approach, the surgical technique to correct the defect itself was simplified. The success of this new simplified technique was previously demonstrated in rabbits[8] and sheep[9]. The skin is closed at the midline of the defect. The postnatal correction technique was merely transferred for prenatal utilization before being tested in a fetal model

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Correction procedure

DISCUSSION

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