Surgical outcome of Chiari I malformation in children: clinico-radiological factors and technical aspects.

PURPOSE: The optimal treatment for Chiari I malformation in children is still under debate. The aim of this study was to evaluate the surgical outcome of the pediatric Chiari I malformation,focusing on clinico-radiological factors and technical aspects. METHODS: Fifty-six patients with Chiari I malformation who received surgery at Seoul National University Children's Hospital were included. The mean age was 7.9 years. The patients were divided into three groups: group I (n =8) with hydrocephalus, group II (n =11) without syrinx, and group III (n =37) with syrinx. Group I received shunting operation initially,and others received foramen magnum decompression (FMD). Group III was further subdivided: group IIIa (n =9), minimal intradural manipulation, and group IIIb (n =27), active intradural manipulation. The outcomes were compared between the groups. The mean follow-up period was 75.9 months. RESULTS: In group I, symptoms were resolved or had improved in most patients, with only one patient received additional FMD. Symptoms resolved or improved in 10 (91 %) and 25 cases (84 %) in groups II and III, respectively. Syrinx was markedly decreased in 31 cases (86 %) in group III. FMD was less effective for scoliosis (improved or stabilized in 57 %).The persistence of syrinx was related with an aggravation of scoliosis. The outcomes between group IIIa and IIIb showed no significant difference. CONCLUSIONS: In most pediatric Chiari I patients with hydrocephalus,a shunting operation was sufficient. FMD showed high efficacy in treating patients without hydrocephalus. The extent of the intradural procedure did not have a significant effect on the clinical outcome.