The outcome of 19 infants with complications of Arnold-Chiari malformation and meningomyelocele was reviewed at the Depts. of Pediatrics, Pathology, and Neurosurgery, University of Pennsylvania School of Medicine and the Children’s Hospital of Philadelphia. Vocal cord paralysis and inspiratory stridor alone occurred in 10 (grade I), apnea was an additional symptom in 4 (grade II), and cyanotic spells and dysphagia were associated in 5 (grade III).
Ventricular shunt was performed in 14 infants, with resolution of symptoms in 7 (in 5 of 8 with grade I, 2 of 4 with grade II, and none of 2 with grade III symptoms). Of 10 with posterior fossa decompressions, symptoms resolved in only 2 (in 1 of 4 with grade I, one of 2 with grade II, and none of 4 with grade III symptoms). Within 6 months after symptoms began, one infant with grade II and 3 with grade III died. No deaths occurred with the grade I group. Infants with grade II or III symptoms have more extensive brain stem damage, such as hemorrhage, infarction and necrosis, and carry a poor prognosis whereas those with grade I symptoms often improve after neurosurgical procedures. 
COMMENT: The grading of cases according to complications is useful in investigation, treatment and prognosis. In a previous study from the University of Toronto , decompression was recommended before rapid neurologic deterioration takes place, even if a functioning shunt is present. Of 45 infants with surgical decompression of the Chiari malformation, 28 survived and showed improved neurologic function and in 24 of these, recovery was complete. About 71% died of those patients who developed cardiorespiratory arrest, vocal cord paralysis, or arm weakness within 2 weeks before decompression, compared with 22% of those with more gradual neurologic deterioration.