Symptomatic Arnold-Chiari malformation: review of experience with 22 cases.

Twenty-two patients with closed myelomeningoceles, shunted hydrocephalus, and symptomatic Arnold-Chiari malformations were studied retrospectively. Seventeen of the 22 patients were aged 6 months or younger; five patients were aged 3 to 23 years. Patients in the younger group presented with stridor, apnea, and/or feeding difficulty; those in the older group presented with hemiparesis, quadriparesis, oscillopsia, nystagmus, or opisthotonos. Fourteen of the 17 younger patients underwent surgical decompression of the Arnold-Chiari malformation: 10 within 18 days following the onset of symptoms and four on Day 19 or later. Of the 10 infants with early treatment, five eventually died secondary to continued symptoms and five survived. Of those surviving, three were asymptomatic and two had continuing symptoms but were improved over their preoperative state. Among the four patients undergoing surgery later, two died, one had lessening of stridor, and one had complete relief of symptoms. Of the three infants not undergoing decompression, two died and one eventually became asymptomatic. All five of the older patients underwent decompression and all had complete resolution of their preoperative symptoms and signs. The authors conclude that while decompression of a symptomatic Arnold-Chiari malformation may be effective in children and adults, this treatment does not always improve the clinical condition of infants. This may be the result of ischemic/hypoxic effects on the infant's brain stem, which may not be organized normally at birth.