How should an acute cerebellar infarct be managed in the immediate postoperative period after posterior fossa decompression for Chiari I malformation?

Management of Acute Cerebellar Infarct After Chiari Decompression

Immediate suboccipital decompressive craniectomy with dural expansion should be performed if the patient develops neurological deterioration from cerebellar infarction with mass effect, as 85% of patients progressing to coma die without intervention, while half of those treated surgically achieve good outcomes. 1

Immediate Assessment and Monitoring

• Obtain urgent neuroimaging (CT or MRI) to confirm cerebellar infarction and assess for mass effect, hydrocephalus, or brainstem compression 1
• Monitor closely in a neurological intensive care unit for at least 24 hours, as mass effect can peak on the third day post-infarct but may occur throughout the first week 1
• Approximately 25% of patients with cerebellar stroke develop mass effect causing rapid clinical deterioration 1
• Watch specifically for declining level of consciousness, as this is the key trigger indicating need for surgical intervention 1

Medical Management (Temporizing Only)

Conservative measures provide only transient benefit and should not delay definitive surgical treatment when indicated 1:

• Elevate head of bed 1
• Administer osmotic diuretics (mannitol or hypertonic saline) 1
• Consider hyperventilation 1
• Maintain isotonic saline for fluid management; avoid hypo-osmolar fluids 1
• Maintain blood glucose between 140-180 mg/dL 1

Surgical Decision Algorithm

If Obstructive Hydrocephalus is Present:

Emergency ventriculostomy is a reasonable first-line intervention 1:

• Ventriculostomy alone may relieve symptoms in some patients 1
• Use conservative cerebrospinal fluid drainage to minimize risk of upward herniation 1
• If ventriculostomy fails to improve neurological function, proceed immediately to decompressive suboccipital craniectomy 1

If Mass Effect Without Hydrocephalus or Failed Ventriculostomy:

Proceed directly to decompressive suboccipital craniectomy with dural expansion 1:

• This is a Class I, Level B-NR recommendation from the American Heart Association/American Stroke Association 1
• Surgery should be performed before clinical signs of brainstem compression develop 1
• The bony window should be ≥12 cm in diameter 1
• Accomplish dural relaxation with a large dural augmentation graft, as this is critical for ICP reduction 1
• When deemed safe and indicated, treat obstructive hydrocephalus concurrently with ventriculostomy 1

Critical Pitfalls to Avoid

• Do NOT rely solely on medical management when neurological deterioration occurs—conservative measures are inadequate for space-occupying cerebellar infarction 1
• Do NOT place external ventricular drain alone without planning for decompressive craniectomy, as EVD alone carries risk of upward herniation and continued brainstem mass effect 1
• Do NOT delay surgery waiting for further deterioration—early intervention before brainstem compression yields better outcomes 1
• This complication may be delayed up to 24 hours postoperatively, so maintain high index of suspicion 2

Postoperative Considerations

• Continue neurological intensive care monitoring with arterial blood pressure monitoring 1
• Maintain normotensive and euvolemic conditions 1
• Early extubation after posterior fossa surgery can be problematic due to abnormal oropharyngeal function, lack of strong cough, and copious secretions 1
• Perform postoperative imaging to confirm adequate decompression 1
• Approximately 50% of patients treated with suboccipital decompression for cerebellar infarction with coma achieve good outcomes 1