Experience with Arnold-Chiari malformation, 1960 to 1970.

A retrospective study of 60 adult patients with Arnold-Chiari malformation revealed that certain presenting clinical syndromes, although not pathognomonic, seemed to have definite prognostic significance. Surgical management by suboccipital decompression led to remarkable and enduring improvement in 65% of patients followed for as long as 14 years. In some patients, however, the initial postoperative benefit tended to fade into an insidious progression of neurological deficit. Despite operation, 18.6% of patients eventually experienced progressive neurological deterioration. Patients who presented with paroxysmal intracranial hypertension or cerebellar dysfunction had the best prognosis. Evidence of central cord involvement was the single most detrimental factor to neurological recovery.