AIm:To assess the effectiveness and safety of pre-resection endoscopic third ventriculostomy (ETV) in permanently relieving hydrocephalus in children with posterior fossa tumors. mAterIAl and methOds: 17 pediatric patients with posterior fossa tumors and associated triventricular obstructive hydrocephalus underwent ETV before definitive tumor resection, and ETV was repeated after tumor resection if hydrocephalus with increased intracranial pressure persisted or recurred. The medical records, operative notes and imaging studies were retrospectively reviewed.results: 18 ETV procedures were performed in 17 patients, consisting of 11 males and 6 females, age range (1.5 to 13 years; mean 6±3.86). Follow-up periods ranged from 6 to 23 months (mean follow-up 13.9±5.4 months). ETV was successful in relieving hydrocephalus during the follow-up period in 15 out of 17 patients (88.2%). Prior to surgical excision of the posterior fossa tumors, no failures of ETV were detected and all of the 17 patients showed marked clinical improvement and radiological disappearance of signs of active hydrocephalus.COnClusIOn: Preoperative ETV is a highly effective long-term CSF diversion procedure for treatment of hydrocephalus associated with posterior fossa tumors in children. In experienced hands, ETV has a very low complication rate.KeywOrds: Hydrocephalus, Endoscopic third ventriculostomy, Posterior fossa tumor ÖZ AmAÇ: Posterior fossa tümörlü çocuklarda hidrosefaliyi kalıcı olarak tedavi etmek üzere rezeksiyon öncesi endoskopik üçüncü ventrikülosto-minin (ETV) etkinlik ve güvenliğini değerlendirme. yÖntem ve GereÇler: Posterior fossa tümörlü ve ilişkili triventriküler obstrüktif hidrosefalili 17 pediatrik hastada kesin tümör rezeksiyonu öncesinde ETV yapıldı ve ETV işlemi eğer artmış intrakraniyal basınçlı hidrosefali devam ediyorsa veya tekrarlarsa tümör rezeksiyonu sonrasında tekrarlandı. Tıbbi kayıtlar, ameliyat notları ve görüntüleme çalışmaları retrospektif olarak gözden geçirildi.BulGulAr: Yaş aralığı 1,5-13 yıl (ortalama 6±3,86) olan ve 11 erkek ve 6 kadından oluşan 17 hastada 18 ETV işlemi yapıldı. Takip dönemleri 6 ile 23 ay arasındaydı (ortalama takip 13,9±5,4 ay). ETV, takip döneminde 17 hastanın 15'inde (%88,2) hidrosefaliyi tedavi etmekte başarılıydı. Posterior fossa tümörlerinin cerrahi insizyonu öncesinde herhangi bir ETV başarısızlığı saptanmadı ve 17 hastanın tümünde belirgin klinik iyileşme ve aktif hidrosefali bulgularının radyolojik olarak kaybolması görüldü. sOnuÇ: Preoperatif ETV çocuklarda posterior fossa tümörleriyle ilişkili hidrosefalinin tedavisinde çok etkin, uzun dönemli bir BOS dİversiyonu işlemidir. Deneyimli ellerde, ETV'nin komplikasyon oranı çok düşüktür AnAhtAr sÖZCÜKler: Hidrosefali, Endoskopik üçüncü ventrikülostomi, Posterior fossa tümörü

Background:Colloid cysts are usually located at the rostral part of the third ventricle in proximity to the foramina of Monro. Some third ventricular colloid cysts, however, attain large sizes, reach a very high distance above the roof of the third ventricle, and pose some challenges during endoscopic excision. These features led to the speculation that for such a pattern of growth to take place, the points of origin of these cysts should be at areas away from the foramina of Monro at which some anatomical “windows” exist that are devoid of compact, closely apposed forniceal structures.Methods:A review of the literature on anatomical variations of the structures in the vicinity of the roof of the third ventricle and on reported cases with similar features was conducted.Results:Colloid cysts may grow vertically up past the roof of the third ventricle through anatomical windows devoid of the mechanical restraint of the forniceal structures.Conclusion:Some anatomical variations of the forniceal structures may allow unusually large sizes and superior vector of growth of a retro- or post-foraminal colloid cyst. Careful preoperative planning and knowledge of the pertinent pathoanatomy of these cysts before endoscopic excision is very important to avoid complications.

The surgical technique of endoscopic foraminoplasty plus septum pellucidotomy for adult idiopathic membranous obstruction of the foramen of Monro is described.

John Edwin Scarff (1898-1978) was one of the pioneers of neuroendoscopy and the head of the Department of Neurological Surgery at Columbia University in New York from 1947 to 1949. In this article, we highlight the pioneering and longstanding efforts of John E. Scarff in support of endoscopic choroid plexus coagulation. These efforts represent an important part of the rich history of neuroendoscopy and a legacy to which the current procedure owes a great credit.

Background:We report a case of a neonate with proximal spinal muscular atrophy (SMA) type 1 (also known as Werdnig-Hoffmann disease or severe infantile acute SMA) associated with a Blake's pouch cyst; a malformation that is currently classified within the spectrum of Dandy-Walker complex. The association of the two conditions has not been previously reported in the English literature. A comprehensive review of the pertinent literature is presented.Case Description:A male neonate was noted to have paucity of movement of the four limbs with difficulty of breathing and poor feeding soon after birth. Respiratory distress with tachypnea, necessitated endotracheal intubation and mechanical ventilation. Pregnancy was uneventful except for decreased fetal movements reported by the mother during the third trimester. Neurological examination revealed generalized hypotonia with decreased muscle power of all limbs, nonelicitable deep tendon jerks, and occasional tongue fasciculations. Molecular genetic evaluation revealed a homozygous deletion of both exons 7 and 8 of the survival motor neuron 1 (SMN1) gene, and exon 5 of the neuronal apoptosis inhibitory protein (NAIP) gene on the long arm of chromosome 5 consistent with Werdnig-Hoffmann disease (SMA type 1). At the age of 5 months, a full anterior fontanelle and abnormal increase of the occipito-frontal circumference were noted. Computed tomographic (CT) scan and magnetic resonance imaging (MRI) of the brain revealed a tetraventricular hydrocephalus and features of Blake's pouch cyst of the fourth ventricle.Conclusions:This case represents a previously unreported association of Blake's pouch cyst and SMA type 1.