Presentation and management of pediatric Chiari malformations without myelodysplasia.

Chiari malformations without myelodysplasia are rarely diagnosed in the pediatric age group. With current neurodiagnostic techniques, however, they are being seen more frequently. Unfortunately, the prognosis is not clear because publications have included a number of different entities, used a variety of surgical approaches, and lacked long term follow-up. Sixteen patients younger than 20 years were treated for Chiari malformations (without myelodysplasia) between 1975 and 1985. The average age was 11 years, and the average duration of symptoms was 20 months. The common symptoms were isolated motor weakness (56%), pain (37.5%), and sensory loss (25%). Frequently seen signs were motor deficit (81%), sensory loss (50%), scoliosis (50%), and cranial nerve palsy (50%). The surgical procedures used were foramen magnum decompression (3 transoral clivus odontoid resections and 15 posterior fossa decompressions with dural grafting), alteration of cerebrospinal fluid (CSF) pathways at the cervicomedullary junction (plugging the foramen cecum and a 4th ventricle to subarachnoid shunt with posterior fossa decompression), and ventriculoperitoneal shunting (2 cases). In follow-up, 37.5% of the patients are asymptomatic, 50% are improved, and 12.5% are stable after an average follow-up period of 43 months. The asymptomatic group was younger (9.3 years) and had a shorter symptom duration (7.2 months) than both the improved (11.9 years, 16.4 months) and the stable groups (15 years, 20 months). Optimal outcome depends on complete evaluation of the abnormal CSF pathways and bony abnormalities at the craniovertebral junction. Operation is then directed toward correction of these abnormalities as delineated radiographically. Of our patients, 87.5% have at least shown improvement, which has been long term in all cases.