The evolution of cerebellar tonsillar herniation after cranial vault remodeling surgery.
OBJECTIVE
We sought to examine the pre- and postoperative changes of cerebellar tonsillar herniation by MR imaging in asymptomatic pediatric patients with nonsyndromic, single-suture craniosynostosis (N-SSSC), who underwent cranial vault remodeling surgery without suboccipital decompression. We required cerebellar tonsillar herniation through foramen magnum ≥3 mm for Chiari type I malformation (CMI). We hypothesized that the increase of intracranial volume by cranial vault remodeling would correct the asymptomatic CMI.


METHODS
We identified 9 patients among 121 N-SSSC children undergoing craniofacial surgery from January 2004 to October 2010 with CMI. However, two of them were excluded from the study due to missing postoperative MR images. In the final study population, six were males, five were scaphocephalic, while two were diagnosed with coronal synostosis.


RESULTS
In four of the cases, the CMI was decreased in postoperative MR imaging varying from 6 to 12 mm. In three cases, the herniation remained stable. The median change of cerebellar tonsillar herniation was -6.5 mm.


CONCLUSIONS
We conclude that asymptomatic patients with existing CMI may benefit from cranial vault remodeling surgery alone increasing the intracranial volume.
Cleft Lip and Palate and Craniofacial Centre, Department of Plastic Surgery, Helsinki University Hospital, Institute of Clinical Medicine, University of Helsinki, Helsinki, Finland. junnu.leikola@hus.fi
J
J
Leikola
A
A
Hukki
A
A
Karppinen
L
L
Valanne
V
V
Koljonen
D000293:Adolescent; D000328:Adult; D000368:Aged; D001139:Arnold-Chiari Malformation / Q000601:surgery; D002648:Child; D003398:Craniosynostoses / Q000601:surgery; D004677:Encephalocele / Q000209:etiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008588:Meningocele / Q000209:etiology*; D008875:Middle Aged; D011183:Postoperative Complications; D012189:Retrospective Studies