Chari 1 malformation, a radiologic finding of caudal cerebellar tonsillar displacement, has a clinical course that can range from benign to complications involving life-threatening hydrocephalus. While the pathophysiologic processes underlying this variation in outcome remain a matter of scientific debate, the clinical realities and decision-making conundrums that these patients pose require a coherent approach to this entity. In this review, we seek to highlight the various processes underlying the development of hydrocephalus in patients with Chiari 1 malformations. Hydrocephalus may occur as a cause, consequence, or in parallel with the development of Chiari 1 malformation, and understanding the etiology of such hydrocephalus is critical to the treatment of Chiari 1 malformations with associated hydrocephalus. We further discuss the literature pertaining to the management of these patients and unify the current scientific thinking on Chiari 1 malformations with the extant data on operative management of Chiari 1 to develop a structured and pragmatic approach to the diagnosis and management of patients with Chiari 1-associated hydrocephalus.

UNASSIGNED: Chiari malformation type III (CM III) is the rarest type compared to other types of CMs. CM III usually reported as sporadic case reports which reflect the rarity of this anomaly. We report two cases of operated CM III at our institute with a reasonable outcome and reviewed the literature to illustrate the variability of prognosis and related hydrocephalus.
UNASSIGNED: We operated two cases of CM III in our hospital followed by ventriculoperitoneal shunt (VPS) placement with an accepted neurological outcome at 10 and 6 months follow-up. We reviewed the literature for other cases of CM III with focusing on prognosis to illustrate the real image of reported prognosis and related hydrocephalus.
UNASSIGNED: After follow-up for 10 and 6 months, respectively, both cases had mild developmental delays. In this review, we report 51 cases of CM III over the last 30 years since 1989, there was slight male predilection, hydrocephalus was evident in 27 cases which was almost managed with VPSs and was evident in seven deaths.
UNASSIGNED: CM III is a rare anomaly which usually carries a bad prognosis, but death is not ultimate, and there may be a minority who carry good prognosis. This bad prognosis pushes some parents to refuse surgery otherwise repair should be done. With good pre- and postoperative care, physical therapy, and follow-up, the outcome is reasonable.

Part 1 of this series of two articles describes conventional and advanced MRI techniques that are useful for evaluating brainstem pathologies. In addition, it provides a review of the embryology, normal progression of myelination, and clinically and radiologically salient imaging anatomy of the normal brainstem. Finally, it discusses congenital diseases of the brainstem with a focus on distinctive imaging features that allow for differentiating pathologies. Part 2 of this series of two articles includes discussion of neoplasms; infections; and vascular, demyelinating, toxic and metabolic, and miscellaneous disease processes affecting the brainstem. The ultimate goal of this pair of articles is to empower the radiologist to add clinical value in the care of pediatric patients with brainstem pathologies.