Chiari I anatomy after ventriculoperitoneal shunting: Posterior fossa volumetric evaluation with MRI
Department of Anatomy, University of Ibadan, Ibadan, Nigeria; Division of Neurosurgery, UCLA School of Medicine, Box 957039, Los Angeles, CA 90095-7039, United States; Department of Radiology, UCLA School of Medicine, Box 957039, Los Angeles, CA 90095-703
Introduction: Cephalocranial disproportion was said to be responsible for Chiari I malformation after ventriculoperitoneal shunt. We aimed to evaluate if the volumetric characteristics of Chiari I after a ventriculoperitoneal shunt was due to a general volumetric reduction and if it is restricted to the posterior fossa. Results: Our results show that the posterior fossa volume, cisternal, clival length, and posterior cranial fossa volume ratio were reduced in the shunted group compared to the controls (p<0.05). Cerebellar and supratentorial volumes were similar between both groups. Craniocaudal extent, inferior, and superior tonsillar herniations were greater in the shunted group than control (p<0.05). The frontal occipital horn ratio in both groups was within normal range. Discussion: Chiari I anatomy after a ventriculoperitoneal shunt could develop in children and we propose a "posterior cranial fossa disproportion" rather than a "cephalocranial disproportion." © Springer-Verlag 2006.
adolescent; Arnold Chiari malformation; article; brain decompression; brain ventricle peritoneum shunt; child; clinical article; clivus; cohort analysis; computer assisted tomography; controlled study; female; human; hydrocephalus; male; nuclear magnetic resonance imaging; posterior fossa; priority journal; statistical significance; volumetry; Arnold-Chiari Malformation; Child, Preschool; Cranial Fossa, Posterior; Female; Humans; Magnetic Resonance Imaging; Male; Ventriculoperitoneal Shunt