Occipital Encephalocele: Cause, Incidence, Neuroimaging and Surgical Management.

AIMS: To review and present the current knowledge of incidence, signs and symptoms, diagnosis and treatment of the occipital encephalocele. BACKGROUND: Encephalocele (E) is a defect of the neural tube that refers to congenital malformations featured by skull defect and dura with extracranial spread of intracranial structures. Occipital encephalocele (OE) are the most common form of this congenital disorder and are manifested as a swelling of different sizes over the occipital bone in the midline. Proper diagnosis and treatment is highly important in the management of this congenital malformation of brain. OBJECTIVE: To review and present the current knowledge of incidence, signs and symptoms, diagnosis and treatment of the occipital encephalocele. METHODS: We conducted a search of case reports or case-series of patients by the use of electronic databases: Pub Med, Medline, Index Medicus, Scorpus. The key words were: encephalocele, occipital encephalocele, neural tube defect, congenital malformation. The search was updated to December 31, 2018. Papers published in English were the only source of information. RESULTS: Occipital encephalocelle are more frequent in females than in males. The incidence is between 1 in 3000 to 1 in 10,000 live births; approximately 90% of them involve the midline. Magnetic resonance imaging is the method of choice in diagnosis and surgery is the best option for the treatment of OE. Overall morbidity and mortality is still high in spite of advenced surgical management, but have been significantly improved in recent years thanks to sophisticated highresolution imaging, adequate and proper surgical treatment and decent post-operative care. CONCLUSION: Occipital encephalocele is the most common form of encephalocele. The diagnosis is mostly based by the use of neuroimaging techniques. Operation is the best option for treatment. Overall morbidity and mortality is still high, but have been significantly improved in recent years thanks to sophisticated high-resolution imaging, adequate and proper surgical treatment and decent post-operative care.

Cerebellar herniation demonstrated by the occipitum-dens line: Ultrasonography assessment of normal fetuses, fetuses with myelomeningocele, and fetuses that underwent antenatal myelomeningocele surgery.

OBJECTIVE: To establish a method to quantify the position of the cerebellum by ultrasonography in normal fetuses, fetuses with myelomeningocele (MMC), and fetuses that underwent in utero MMC repair. METHODS: Reference points identifiable on ultrasound were established. The basilar portion of the occipital bone and upper portion of the odontoid process were considered as the external and internal limits, respectively, of the level zero of a line that was designated the occipitum-dens line (ODL). Eighty-three normal fetuses were assessed 1 occasion (cross-sectional study) in addition to 25 fetuses with MMC and 25 fetuses that underwent in utero MMC repair. The groups were compared using analysis of variance or the Kruskal-Wallis test. The intraclass correlation coefficient (ICC) was used to determine intra- and interobserver reproducibility. RESULTS: The analysis of ODL indicated that all normal fetuses had the cerebellar tonsil above level zero at a mean distance of 2.8 ± 1.1 mm (P = 0.125). The fetuses with MMC had the cerebellar tonsil below level zero, except in 2 cases of myelocystocele. All the fetuses that underwent in utero MMC repair exhibited regression of the cerebellar herniation (0.5 mm per week, P < 0.005). Herniation increased gradually (1.0 mm per week, P < 0.005) in fetuses that did not undergo MMC repair. ICC indicated good intra- and interobserver reproducibility (0.996 and 0.983, respectively). CONCLUSION: The reference points for ODL may be used to assess cerebellar height. ODL allowed the demonstration of the regression of cerebellar herniation in fetuses that underwent in utero MMC repair.