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Updated: Dec 8, 2025
Neuronavigation and Laparoscopy Guided Ventriculoperitoneal Shunt Insertion for the Treatment of Hydrocephalus
Published on: October 14, 2022
"Growing cerebellum" requiring operative decompression following perinatal ventriculoperitoneal shunting
Astrid C Hengartner1, Matthew Putty2, Michael Young2
1Department of Pediatric Neurosurgery, Children's Hospital Colorado, University of Colorado School of Medicine, 13123 E 16th Ave, Aurora, CO, 80045, USA.
Insights
Acquired Chiari I malformation after ventriculoperitoneal shunting is rare. This case highlights disproportionate cerebellar growth as a cause, successfully treated with posterior fossa decompression.
Area of Science:
- Pediatric Neurosurgery
- Neurology
- Developmental Biology
Background:
- Ventriculoperitoneal shunting is used for posthemorrhagic hydrocephalus in premature neonates.
- Acquired Chiari I malformation can occur post-shunting, but disproportionate cerebellar growth is exceptionally rare.
- Previous cases often involve underdevelopment of cranial fossae volume.
Purpose of the Study:
- To report a rare case of acquired Chiari I malformation due to disproportionate cerebellar growth in a neonate.
- To discuss the potential variant mechanism of craniocerebral disproportion following shunting.
- To highlight the importance of distinguishing between different patterns of craniocerebral disproportion.
Main Methods:
- Case presentation of a premature neonate with posthemorrhagic hydrocephalus treated with ventriculoperitoneal shunt.
- Volumetric measurements to assess cerebellar growth and cranial vault dimensions.
- Literature review on Chiari I malformation and craniocerebral disproportion post-shunting.
Main Results:
- The neonate developed symptomatic Chiari I malformation with disproportionate cerebellar growth.
- The patient did not show cranial thickening.
- Successful management with extradural posterior fossa decompression was achieved.
Conclusions:
- Disproportionate cerebellar growth represents a rare variant mechanism for acquired Chiari I malformation post-shunting.
- Distinguishing between cerebellar overgrowth and cranial vault underdevelopment is crucial for treatment selection.
- Further research is needed to elucidate the mechanisms in these uncommon cases.
Introduction:
While cases of acquired Chiari I malformation following ventriculoperitoneal shunting for posthemorrhagic hydrocephalus have been reported, true disproportionate cerebellar growth is rare, with no previous cases requiring posterior fossa decompression reported.
Clinical Presentation:
We present a premature neonate who underwent ventriculoperitoneal shunt placement for suspected posthemorrhagic hydrocephalus. He subsequently developed a symptomatic Chiari I malformation with volumetric measurements demonstrating disproportionate growth of the cerebellum. He did not demonstrate thickening of the supratentorial or posterior fossa cranium. The patient underwent an extradural posterior fossa decompression, with resolution of symptoms.
Outcome And Conclusions:
We review the extant literature regarding the development of Chiari malformation type I as a manifestation of craniocerebral disproportion (CCD) following shunt placement for posthemorrhagic hydrocephalus of prematurity. Most previous reports reflect a mechanism that includes underdevelopment of the intracranial posterior fossa (or supratentorial) volume. The case presented in this report, as well as one additional case, indicates that there may exist a variant mechanism, characterized by rapid growth of the cerebellum itself, in the absence of one of the rare syndromes associated with primary macrocerebellum. While this case was effectively managed with extradural posterior fossa decompression, previous reports indicate that supratentorial cranial expansion procedures are preferable in some cases. As such, pediatric neurosurgeons should be able to distinguish the patterns of craniocerebral disproportion when considering treatment options for these patients. Further investigation regarding these uncommon patients may better describe the underlying mechanisms.
