Intracranial hypertension after surgery in patients with Chiari I malformation and normal or moderate increase in ventricular size.
OBJECTIVE
To determine ICP changes in patients with Chiari type I malformation after posterior fossa reconstruction (PFR).


METHODS
We continuously monitored ICP before and after PFR in 12 patients with Chiari I malformation and with an Evans' Index below or equal to 0.33. Mean ICP (epidural sensor) and percentage of B waves were calculated 24 hours before surgery and during the first 7 days after surgery.


RESULTS
Mean ICP and percentage of B waves significantly increased after surgery despite a significant increase in the volume of the posterior fossa. The main finding revealed by control CT scans was compression of the quadrigeminal cistern with a reduction in size of the fourth ventricle. In six patients, a small transitory increase in supratentorial ventricular size was found.


CONCLUSIONS
A transitory increase in ICP is common after PFR. This increase could be explained by an initial reperfusion phenomena in the cerebellum that provokes a transitory deterioration in CSF dynamics. The effacement of the quadrigeminal cistern and the reduction in size of the fourth ventricle suggests this hypothesis.
Poca
M A
MA
Department of Neurosurgery, Vall d'Hebron University Hospitals, Barcelona, Spain.
Sahuquillo
J
J
Ibañez
J
J
Amorós
S
S
Arikan
F
F
Rubio
E
E
D000328:Adult; D001139:Arnold-Chiari Malformation / Q000601:surgery*; D003388:Cranial Fossa, Posterior / Q000473:pathology / Q000601:surgery*; D004388:Dura Mater / Q000637:transplantation; D005260:Female; D005500:Follow-Up Studies; D006261:Headache / Q000209:etiology; D006801:Humans; D019586:Intracranial Hypertension / Q000209:etiology*; D007427:Intracranial Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D011183:Postoperative Complications / Q000503:physiopathology*; D013595:Syringomyelia / Q000150:complications; D013997:Time Factors; D014184:Transplantation, Homologous