PurposeTo analyze the pathways to brainstem tumors in childhood, as well as safe entry zones.MethodWe conducted a retrospective study of 207 patients less than 18 years old who underwent brainstem tumor resection by the first author (Cavalheiro, S.) at the Neurosurgical Service and Pediatric Oncology Institute of the São Paulo Federal University from 1991 to 2011.ResultsBrainstem tumors corresponded to 9.1 % of all pediatric tumors operated in that same period. Eleven previously described “safe entry zones” were used. We describe a new safe zone located in the superior ventral pons, which we named supratrigeminal approach. The operative mortality seen in the first 2 months after surgery was 1.9 % (four patients), and the morbidity rate was 21.2 %.ConclusionsAnatomic knowledge of intrinsic and extrinsic brainstem structures, in association with a refined neurosurgical technique assisted by intraoperative monitoring, and surgical planning based on magnetic resonance imaging (MRI) and tractography have allowed for wide resection of brainstem lesions with low mortality and acceptable morbidity rates.

OBJECTIVEIn this study, the authors retrospectively reviewed two cohorts of patients with occipital encephalocele (OE) and demonstrate the technical aspects of an innovative and unprecedented method for fetal OE correction.METHODSThis was a cross-sectional retrospective study of 22 patients who underwent surgery from July 2012 to July 2018. The inclusion criteria for participants were a gestational age between 19 weeks and 27 weeks, a maternal age ≥ 18 years, a normal fetal karyotype, the presence of microcephaly, and a cystic hernial sac with the cystic component accounting for more than 80% of the total volume, which was larger than 10 ml. The fetuses with OE and microcephaly underwent intrauterine repair. The exclusion criteria were the presence of a fetal anomaly not associated with OE, chromosomopathy, presence of the brainstem inside the hernial sac or venous sinuses inside the herniated content, the risk of premature birth, placenta previa, and maternal conditions that would constitute an additional risk for fetal and maternal health, as well as refusal for fetal surgery. The authors reviewed the potential for microcephaly reversal and the long-term neurocognitive development.RESULTSThe authors report the cases of 9 fetuses with OE and microcephaly who underwent intrauterine OE repair at gestational ages of less than 27 weeks (fetal group). One case selected for fetal surgery also presented with placental abruption. All patients who underwent the fetal operation had microcephaly reversal, and 3 patients required ventriculoperitoneal shunting in the 1st year of life. The authors reviewed the cases of 12 patients who underwent postnatal repair. In 10 cases, fetal surgery was refused (postnatal group), and in 2 cases, the inclusion criteria for fetal surgery were not met. The authors evaluated the neurocognitive development of the patients with the Bayley Scales of Infant Development II. The median score for the fetal group was 98.7, and that for the postnatal group was 27.8.CONCLUSIONSThe intrauterine repair of OE may stop the progression of encephalocele sac herniation and result in microcephaly reversal. The fetal group had a better cognitive outcome than the postnatal group. The technique required to correct this defect is feasible for those with previous experience in the correction of fetal myelomeningocele. However, more studies are needed to ensure the efficacy of this procedure.

The advance in the imaging tools during the pregnancy (ultrasound and magnetic resonance) allowed the early diagnose of many fetal diseases, including the neurological conditions. This progress brought the neurosurgeons the possibility to propose treatments even before birth. Myelomeningocele is the most recognized disease that can be treated during pregnancy with a high rate of success. Additionally, this field can be extended to other conditions such as hydrocephalus and encephaloceles. However, each one of these diseases has nuances in the diagnostic evaluation that should fit the requirements to perform the fetal procedure and overbalance the benefits to the patients. In this article, the authors aim to review the neurosurgical aspects of the antenatal management of neurosurgical conditions based on the experience of a pediatric neurosurgery center.

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