Chiari I malformation with syringomyelia. Evaluation of surgical therapy by magnetic resonance imaging.

Five patients with a Chiari I-syringomyelia complex of adult onset were evaluated by magnetic resonance (MR) imaging. All patients underwent suboccipital craniotomy with upper cervical (C-1 and part of C-2) laminectomy, arachnoid retraction, and duraplasty. Postoperative MR studies of four patients disclosed collapse of the syringomyelic cavity, even when the cavity extended into the thoracic region. This appeared to be a progressive process taking place over several weeks. Operative complications are noted and physiological implications are discussed.